Bug Summary

File:src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/CodeGen/InlineSpiller.cpp
Warning:line 1348, column 14
Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name InlineSpiller.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 1 -fhalf-no-semantic-interposition -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/gnu/usr.bin/clang/libLLVM/obj -resource-dir /usr/local/lib/clang/13.0.0 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/AMDGPU -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Analysis -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ASMParser -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/BinaryFormat -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Bitcode -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Bitcode -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Bitstream -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /include/llvm/CodeGen -I /include/llvm/CodeGen/PBQP -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/IR -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/IR -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/Coroutines -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ProfileData/Coverage -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo/CodeView -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo/DWARF -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo/MSF -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo/PDB -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Demangle -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ExecutionEngine -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ExecutionEngine/JITLink -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ExecutionEngine/Orc -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Frontend -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Frontend/OpenACC -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Frontend -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Frontend/OpenMP -I /include/llvm/CodeGen/GlobalISel -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/IRReader -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/InstCombine -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/Transforms/InstCombine -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/LTO -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Linker -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/MC -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/MC/MCParser -I /include/llvm/CodeGen/MIRParser -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Object -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Option -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Passes -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ProfileData -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/Scalar -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ADT -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Support -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/DebugInfo/Symbolize -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Target -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/Utils -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/Vectorize -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include/llvm/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/Target/X86 -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Transforms/IPO -I /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include -I /usr/src/gnu/usr.bin/clang/libLLVM/../include -I /usr/src/gnu/usr.bin/clang/libLLVM/obj -I /usr/src/gnu/usr.bin/clang/libLLVM/obj/../include -D NDEBUG -D __STDC_LIMIT_MACROS -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D LLVM_PREFIX="/usr" -D PIC -internal-isystem /usr/include/c++/v1 -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir=/usr/src/gnu/usr.bin/clang/libLLVM/obj -ferror-limit 19 -fvisibility-inlines-hidden -fwrapv -D_RET_PROTECTOR -ret-protector -fno-rtti -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c++ /usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/CodeGen/InlineSpiller.cpp

/usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/CodeGen/InlineSpiller.cpp

1//===- InlineSpiller.cpp - Insert spills and restores inline --------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// The inline spiller modifies the machine function directly instead of
10// inserting spills and restores in VirtRegMap.
11//
12//===----------------------------------------------------------------------===//
13
14#include "SplitKit.h"
15#include "llvm/ADT/ArrayRef.h"
16#include "llvm/ADT/DenseMap.h"
17#include "llvm/ADT/MapVector.h"
18#include "llvm/ADT/None.h"
19#include "llvm/ADT/STLExtras.h"
20#include "llvm/ADT/SetVector.h"
21#include "llvm/ADT/SmallPtrSet.h"
22#include "llvm/ADT/SmallVector.h"
23#include "llvm/ADT/Statistic.h"
24#include "llvm/Analysis/AliasAnalysis.h"
25#include "llvm/CodeGen/LiveInterval.h"
26#include "llvm/CodeGen/LiveIntervalCalc.h"
27#include "llvm/CodeGen/LiveIntervals.h"
28#include "llvm/CodeGen/LiveRangeEdit.h"
29#include "llvm/CodeGen/LiveStacks.h"
30#include "llvm/CodeGen/MachineBasicBlock.h"
31#include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
32#include "llvm/CodeGen/MachineDominators.h"
33#include "llvm/CodeGen/MachineFunction.h"
34#include "llvm/CodeGen/MachineFunctionPass.h"
35#include "llvm/CodeGen/MachineInstr.h"
36#include "llvm/CodeGen/MachineInstrBuilder.h"
37#include "llvm/CodeGen/MachineInstrBundle.h"
38#include "llvm/CodeGen/MachineLoopInfo.h"
39#include "llvm/CodeGen/MachineOperand.h"
40#include "llvm/CodeGen/MachineRegisterInfo.h"
41#include "llvm/CodeGen/SlotIndexes.h"
42#include "llvm/CodeGen/Spiller.h"
43#include "llvm/CodeGen/StackMaps.h"
44#include "llvm/CodeGen/TargetInstrInfo.h"
45#include "llvm/CodeGen/TargetOpcodes.h"
46#include "llvm/CodeGen/TargetRegisterInfo.h"
47#include "llvm/CodeGen/TargetSubtargetInfo.h"
48#include "llvm/CodeGen/VirtRegMap.h"
49#include "llvm/Config/llvm-config.h"
50#include "llvm/Support/BlockFrequency.h"
51#include "llvm/Support/BranchProbability.h"
52#include "llvm/Support/CommandLine.h"
53#include "llvm/Support/Compiler.h"
54#include "llvm/Support/Debug.h"
55#include "llvm/Support/ErrorHandling.h"
56#include "llvm/Support/raw_ostream.h"
57#include <cassert>
58#include <iterator>
59#include <tuple>
60#include <utility>
61#include <vector>
62
63using namespace llvm;
64
65#define DEBUG_TYPE"regalloc" "regalloc"
66
67STATISTIC(NumSpilledRanges, "Number of spilled live ranges")static llvm::Statistic NumSpilledRanges = {"regalloc", "NumSpilledRanges"
, "Number of spilled live ranges"}
;
68STATISTIC(NumSnippets, "Number of spilled snippets")static llvm::Statistic NumSnippets = {"regalloc", "NumSnippets"
, "Number of spilled snippets"}
;
69STATISTIC(NumSpills, "Number of spills inserted")static llvm::Statistic NumSpills = {"regalloc", "NumSpills", "Number of spills inserted"
}
;
70STATISTIC(NumSpillsRemoved, "Number of spills removed")static llvm::Statistic NumSpillsRemoved = {"regalloc", "NumSpillsRemoved"
, "Number of spills removed"}
;
71STATISTIC(NumReloads, "Number of reloads inserted")static llvm::Statistic NumReloads = {"regalloc", "NumReloads"
, "Number of reloads inserted"}
;
72STATISTIC(NumReloadsRemoved, "Number of reloads removed")static llvm::Statistic NumReloadsRemoved = {"regalloc", "NumReloadsRemoved"
, "Number of reloads removed"}
;
73STATISTIC(NumFolded, "Number of folded stack accesses")static llvm::Statistic NumFolded = {"regalloc", "NumFolded", "Number of folded stack accesses"
}
;
74STATISTIC(NumFoldedLoads, "Number of folded loads")static llvm::Statistic NumFoldedLoads = {"regalloc", "NumFoldedLoads"
, "Number of folded loads"}
;
75STATISTIC(NumRemats, "Number of rematerialized defs for spilling")static llvm::Statistic NumRemats = {"regalloc", "NumRemats", "Number of rematerialized defs for spilling"
}
;
76
77static cl::opt<bool> DisableHoisting("disable-spill-hoist", cl::Hidden,
78 cl::desc("Disable inline spill hoisting"));
79static cl::opt<bool>
80RestrictStatepointRemat("restrict-statepoint-remat",
81 cl::init(false), cl::Hidden,
82 cl::desc("Restrict remat for statepoint operands"));
83
84namespace {
85
86class HoistSpillHelper : private LiveRangeEdit::Delegate {
87 MachineFunction &MF;
88 LiveIntervals &LIS;
89 LiveStacks &LSS;
90 AliasAnalysis *AA;
91 MachineDominatorTree &MDT;
92 MachineLoopInfo &Loops;
93 VirtRegMap &VRM;
94 MachineRegisterInfo &MRI;
95 const TargetInstrInfo &TII;
96 const TargetRegisterInfo &TRI;
97 const MachineBlockFrequencyInfo &MBFI;
98
99 InsertPointAnalysis IPA;
100
101 // Map from StackSlot to the LiveInterval of the original register.
102 // Note the LiveInterval of the original register may have been deleted
103 // after it is spilled. We keep a copy here to track the range where
104 // spills can be moved.
105 DenseMap<int, std::unique_ptr<LiveInterval>> StackSlotToOrigLI;
106
107 // Map from pair of (StackSlot and Original VNI) to a set of spills which
108 // have the same stackslot and have equal values defined by Original VNI.
109 // These spills are mergeable and are hoist candiates.
110 using MergeableSpillsMap =
111 MapVector<std::pair<int, VNInfo *>, SmallPtrSet<MachineInstr *, 16>>;
112 MergeableSpillsMap MergeableSpills;
113
114 /// This is the map from original register to a set containing all its
115 /// siblings. To hoist a spill to another BB, we need to find out a live
116 /// sibling there and use it as the source of the new spill.
117 DenseMap<Register, SmallSetVector<Register, 16>> Virt2SiblingsMap;
118
119 bool isSpillCandBB(LiveInterval &OrigLI, VNInfo &OrigVNI,
120 MachineBasicBlock &BB, Register &LiveReg);
121
122 void rmRedundantSpills(
123 SmallPtrSet<MachineInstr *, 16> &Spills,
124 SmallVectorImpl<MachineInstr *> &SpillsToRm,
125 DenseMap<MachineDomTreeNode *, MachineInstr *> &SpillBBToSpill);
126
127 void getVisitOrders(
128 MachineBasicBlock *Root, SmallPtrSet<MachineInstr *, 16> &Spills,
129 SmallVectorImpl<MachineDomTreeNode *> &Orders,
130 SmallVectorImpl<MachineInstr *> &SpillsToRm,
131 DenseMap<MachineDomTreeNode *, unsigned> &SpillsToKeep,
132 DenseMap<MachineDomTreeNode *, MachineInstr *> &SpillBBToSpill);
133
134 void runHoistSpills(LiveInterval &OrigLI, VNInfo &OrigVNI,
135 SmallPtrSet<MachineInstr *, 16> &Spills,
136 SmallVectorImpl<MachineInstr *> &SpillsToRm,
137 DenseMap<MachineBasicBlock *, unsigned> &SpillsToIns);
138
139public:
140 HoistSpillHelper(MachineFunctionPass &pass, MachineFunction &mf,
141 VirtRegMap &vrm)
142 : MF(mf), LIS(pass.getAnalysis<LiveIntervals>()),
143 LSS(pass.getAnalysis<LiveStacks>()),
144 AA(&pass.getAnalysis<AAResultsWrapperPass>().getAAResults()),
145 MDT(pass.getAnalysis<MachineDominatorTree>()),
146 Loops(pass.getAnalysis<MachineLoopInfo>()), VRM(vrm),
147 MRI(mf.getRegInfo()), TII(*mf.getSubtarget().getInstrInfo()),
148 TRI(*mf.getSubtarget().getRegisterInfo()),
149 MBFI(pass.getAnalysis<MachineBlockFrequencyInfo>()),
150 IPA(LIS, mf.getNumBlockIDs()) {}
151
152 void addToMergeableSpills(MachineInstr &Spill, int StackSlot,
153 unsigned Original);
154 bool rmFromMergeableSpills(MachineInstr &Spill, int StackSlot);
155 void hoistAllSpills();
156 void LRE_DidCloneVirtReg(Register, Register) override;
157};
158
159class InlineSpiller : public Spiller {
160 MachineFunction &MF;
161 LiveIntervals &LIS;
162 LiveStacks &LSS;
163 AliasAnalysis *AA;
164 MachineDominatorTree &MDT;
165 MachineLoopInfo &Loops;
166 VirtRegMap &VRM;
167 MachineRegisterInfo &MRI;
168 const TargetInstrInfo &TII;
169 const TargetRegisterInfo &TRI;
170 const MachineBlockFrequencyInfo &MBFI;
171
172 // Variables that are valid during spill(), but used by multiple methods.
173 LiveRangeEdit *Edit;
174 LiveInterval *StackInt;
175 int StackSlot;
176 Register Original;
177
178 // All registers to spill to StackSlot, including the main register.
179 SmallVector<Register, 8> RegsToSpill;
180
181 // All COPY instructions to/from snippets.
182 // They are ignored since both operands refer to the same stack slot.
183 SmallPtrSet<MachineInstr*, 8> SnippetCopies;
184
185 // Values that failed to remat at some point.
186 SmallPtrSet<VNInfo*, 8> UsedValues;
187
188 // Dead defs generated during spilling.
189 SmallVector<MachineInstr*, 8> DeadDefs;
190
191 // Object records spills information and does the hoisting.
192 HoistSpillHelper HSpiller;
193
194 // Live range weight calculator.
195 VirtRegAuxInfo &VRAI;
196
197 ~InlineSpiller() override = default;
198
199public:
200 InlineSpiller(MachineFunctionPass &Pass, MachineFunction &MF, VirtRegMap &VRM,
201 VirtRegAuxInfo &VRAI)
202 : MF(MF), LIS(Pass.getAnalysis<LiveIntervals>()),
203 LSS(Pass.getAnalysis<LiveStacks>()),
204 AA(&Pass.getAnalysis<AAResultsWrapperPass>().getAAResults()),
205 MDT(Pass.getAnalysis<MachineDominatorTree>()),
206 Loops(Pass.getAnalysis<MachineLoopInfo>()), VRM(VRM),
207 MRI(MF.getRegInfo()), TII(*MF.getSubtarget().getInstrInfo()),
208 TRI(*MF.getSubtarget().getRegisterInfo()),
209 MBFI(Pass.getAnalysis<MachineBlockFrequencyInfo>()),
210 HSpiller(Pass, MF, VRM), VRAI(VRAI) {}
211
212 void spill(LiveRangeEdit &) override;
213 void postOptimization() override;
214
215private:
216 bool isSnippet(const LiveInterval &SnipLI);
217 void collectRegsToSpill();
218
219 bool isRegToSpill(Register Reg) { return is_contained(RegsToSpill, Reg); }
220
221 bool isSibling(Register Reg);
222 bool hoistSpillInsideBB(LiveInterval &SpillLI, MachineInstr &CopyMI);
223 void eliminateRedundantSpills(LiveInterval &LI, VNInfo *VNI);
224
225 void markValueUsed(LiveInterval*, VNInfo*);
226 bool canGuaranteeAssignmentAfterRemat(Register VReg, MachineInstr &MI);
227 bool reMaterializeFor(LiveInterval &, MachineInstr &MI);
228 void reMaterializeAll();
229
230 bool coalesceStackAccess(MachineInstr *MI, Register Reg);
231 bool foldMemoryOperand(ArrayRef<std::pair<MachineInstr *, unsigned>>,
232 MachineInstr *LoadMI = nullptr);
233 void insertReload(Register VReg, SlotIndex, MachineBasicBlock::iterator MI);
234 void insertSpill(Register VReg, bool isKill, MachineBasicBlock::iterator MI);
235
236 void spillAroundUses(Register Reg);
237 void spillAll();
238};
239
240} // end anonymous namespace
241
242Spiller::~Spiller() = default;
243
244void Spiller::anchor() {}
245
246Spiller *llvm::createInlineSpiller(MachineFunctionPass &Pass,
247 MachineFunction &MF, VirtRegMap &VRM,
248 VirtRegAuxInfo &VRAI) {
249 return new InlineSpiller(Pass, MF, VRM, VRAI);
250}
251
252//===----------------------------------------------------------------------===//
253// Snippets
254//===----------------------------------------------------------------------===//
255
256// When spilling a virtual register, we also spill any snippets it is connected
257// to. The snippets are small live ranges that only have a single real use,
258// leftovers from live range splitting. Spilling them enables memory operand
259// folding or tightens the live range around the single use.
260//
261// This minimizes register pressure and maximizes the store-to-load distance for
262// spill slots which can be important in tight loops.
263
264/// isFullCopyOf - If MI is a COPY to or from Reg, return the other register,
265/// otherwise return 0.
266static Register isFullCopyOf(const MachineInstr &MI, Register Reg) {
267 if (!MI.isFullCopy())
268 return Register();
269 if (MI.getOperand(0).getReg() == Reg)
270 return MI.getOperand(1).getReg();
271 if (MI.getOperand(1).getReg() == Reg)
272 return MI.getOperand(0).getReg();
273 return Register();
274}
275
276static void getVDefInterval(const MachineInstr &MI, LiveIntervals &LIS) {
277 for (unsigned I = 0, E = MI.getNumOperands(); I != E; ++I) {
278 const MachineOperand &MO = MI.getOperand(I);
279 if (MO.isReg() && MO.isDef() && Register::isVirtualRegister(MO.getReg()))
280 LIS.getInterval(MO.getReg());
281 }
282}
283
284/// isSnippet - Identify if a live interval is a snippet that should be spilled.
285/// It is assumed that SnipLI is a virtual register with the same original as
286/// Edit->getReg().
287bool InlineSpiller::isSnippet(const LiveInterval &SnipLI) {
288 Register Reg = Edit->getReg();
289
290 // A snippet is a tiny live range with only a single instruction using it
291 // besides copies to/from Reg or spills/fills. We accept:
292 //
293 // %snip = COPY %Reg / FILL fi#
294 // %snip = USE %snip
295 // %Reg = COPY %snip / SPILL %snip, fi#
296 //
297 if (SnipLI.getNumValNums() > 2 || !LIS.intervalIsInOneMBB(SnipLI))
298 return false;
299
300 MachineInstr *UseMI = nullptr;
301
302 // Check that all uses satisfy our criteria.
303 for (MachineRegisterInfo::reg_instr_nodbg_iterator
304 RI = MRI.reg_instr_nodbg_begin(SnipLI.reg()),
305 E = MRI.reg_instr_nodbg_end();
306 RI != E;) {
307 MachineInstr &MI = *RI++;
308
309 // Allow copies to/from Reg.
310 if (isFullCopyOf(MI, Reg))
311 continue;
312
313 // Allow stack slot loads.
314 int FI;
315 if (SnipLI.reg() == TII.isLoadFromStackSlot(MI, FI) && FI == StackSlot)
316 continue;
317
318 // Allow stack slot stores.
319 if (SnipLI.reg() == TII.isStoreToStackSlot(MI, FI) && FI == StackSlot)
320 continue;
321
322 // Allow a single additional instruction.
323 if (UseMI && &MI != UseMI)
324 return false;
325 UseMI = &MI;
326 }
327 return true;
328}
329
330/// collectRegsToSpill - Collect live range snippets that only have a single
331/// real use.
332void InlineSpiller::collectRegsToSpill() {
333 Register Reg = Edit->getReg();
334
335 // Main register always spills.
336 RegsToSpill.assign(1, Reg);
337 SnippetCopies.clear();
338
339 // Snippets all have the same original, so there can't be any for an original
340 // register.
341 if (Original == Reg)
342 return;
343
344 for (MachineRegisterInfo::reg_instr_iterator
345 RI = MRI.reg_instr_begin(Reg), E = MRI.reg_instr_end(); RI != E; ) {
346 MachineInstr &MI = *RI++;
347 Register SnipReg = isFullCopyOf(MI, Reg);
348 if (!isSibling(SnipReg))
349 continue;
350 LiveInterval &SnipLI = LIS.getInterval(SnipReg);
351 if (!isSnippet(SnipLI))
352 continue;
353 SnippetCopies.insert(&MI);
354 if (isRegToSpill(SnipReg))
355 continue;
356 RegsToSpill.push_back(SnipReg);
357 LLVM_DEBUG(dbgs() << "\talso spill snippet " << SnipLI << '\n')do { } while (false);
358 ++NumSnippets;
359 }
360}
361
362bool InlineSpiller::isSibling(Register Reg) {
363 return Reg.isVirtual() && VRM.getOriginal(Reg) == Original;
364}
365
366/// It is beneficial to spill to earlier place in the same BB in case
367/// as follows:
368/// There is an alternative def earlier in the same MBB.
369/// Hoist the spill as far as possible in SpillMBB. This can ease
370/// register pressure:
371///
372/// x = def
373/// y = use x
374/// s = copy x
375///
376/// Hoisting the spill of s to immediately after the def removes the
377/// interference between x and y:
378///
379/// x = def
380/// spill x
381/// y = use killed x
382///
383/// This hoist only helps when the copy kills its source.
384///
385bool InlineSpiller::hoistSpillInsideBB(LiveInterval &SpillLI,
386 MachineInstr &CopyMI) {
387 SlotIndex Idx = LIS.getInstructionIndex(CopyMI);
388#ifndef NDEBUG1
389 VNInfo *VNI = SpillLI.getVNInfoAt(Idx.getRegSlot());
390 assert(VNI && VNI->def == Idx.getRegSlot() && "Not defined by copy")((void)0);
391#endif
392
393 Register SrcReg = CopyMI.getOperand(1).getReg();
394 LiveInterval &SrcLI = LIS.getInterval(SrcReg);
395 VNInfo *SrcVNI = SrcLI.getVNInfoAt(Idx);
396 LiveQueryResult SrcQ = SrcLI.Query(Idx);
397 MachineBasicBlock *DefMBB = LIS.getMBBFromIndex(SrcVNI->def);
398 if (DefMBB != CopyMI.getParent() || !SrcQ.isKill())
399 return false;
400
401 // Conservatively extend the stack slot range to the range of the original
402 // value. We may be able to do better with stack slot coloring by being more
403 // careful here.
404 assert(StackInt && "No stack slot assigned yet.")((void)0);
405 LiveInterval &OrigLI = LIS.getInterval(Original);
406 VNInfo *OrigVNI = OrigLI.getVNInfoAt(Idx);
407 StackInt->MergeValueInAsValue(OrigLI, OrigVNI, StackInt->getValNumInfo(0));
408 LLVM_DEBUG(dbgs() << "\tmerged orig valno " << OrigVNI->id << ": "do { } while (false)
409 << *StackInt << '\n')do { } while (false);
410
411 // We are going to spill SrcVNI immediately after its def, so clear out
412 // any later spills of the same value.
413 eliminateRedundantSpills(SrcLI, SrcVNI);
414
415 MachineBasicBlock *MBB = LIS.getMBBFromIndex(SrcVNI->def);
416 MachineBasicBlock::iterator MII;
417 if (SrcVNI->isPHIDef())
418 MII = MBB->SkipPHIsLabelsAndDebug(MBB->begin());
419 else {
420 MachineInstr *DefMI = LIS.getInstructionFromIndex(SrcVNI->def);
421 assert(DefMI && "Defining instruction disappeared")((void)0);
422 MII = DefMI;
423 ++MII;
424 }
425 MachineInstrSpan MIS(MII, MBB);
426 // Insert spill without kill flag immediately after def.
427 TII.storeRegToStackSlot(*MBB, MII, SrcReg, false, StackSlot,
428 MRI.getRegClass(SrcReg), &TRI);
429 LIS.InsertMachineInstrRangeInMaps(MIS.begin(), MII);
430 for (const MachineInstr &MI : make_range(MIS.begin(), MII))
431 getVDefInterval(MI, LIS);
432 --MII; // Point to store instruction.
433 LLVM_DEBUG(dbgs() << "\thoisted: " << SrcVNI->def << '\t' << *MII)do { } while (false);
434
435 // If there is only 1 store instruction is required for spill, add it
436 // to mergeable list. In X86 AMX, 2 intructions are required to store.
437 // We disable the merge for this case.
438 if (MIS.begin() == MII)
439 HSpiller.addToMergeableSpills(*MII, StackSlot, Original);
440 ++NumSpills;
441 return true;
442}
443
444/// eliminateRedundantSpills - SLI:VNI is known to be on the stack. Remove any
445/// redundant spills of this value in SLI.reg and sibling copies.
446void InlineSpiller::eliminateRedundantSpills(LiveInterval &SLI, VNInfo *VNI) {
447 assert(VNI && "Missing value")((void)0);
448 SmallVector<std::pair<LiveInterval*, VNInfo*>, 8> WorkList;
449 WorkList.push_back(std::make_pair(&SLI, VNI));
450 assert(StackInt && "No stack slot assigned yet.")((void)0);
451
452 do {
453 LiveInterval *LI;
454 std::tie(LI, VNI) = WorkList.pop_back_val();
455 Register Reg = LI->reg();
456 LLVM_DEBUG(dbgs() << "Checking redundant spills for " << VNI->id << '@'do { } while (false)
457 << VNI->def << " in " << *LI << '\n')do { } while (false);
458
459 // Regs to spill are taken care of.
460 if (isRegToSpill(Reg))
461 continue;
462
463 // Add all of VNI's live range to StackInt.
464 StackInt->MergeValueInAsValue(*LI, VNI, StackInt->getValNumInfo(0));
465 LLVM_DEBUG(dbgs() << "Merged to stack int: " << *StackInt << '\n')do { } while (false);
466
467 // Find all spills and copies of VNI.
468 for (MachineRegisterInfo::use_instr_nodbg_iterator
469 UI = MRI.use_instr_nodbg_begin(Reg), E = MRI.use_instr_nodbg_end();
470 UI != E; ) {
471 MachineInstr &MI = *UI++;
472 if (!MI.isCopy() && !MI.mayStore())
473 continue;
474 SlotIndex Idx = LIS.getInstructionIndex(MI);
475 if (LI->getVNInfoAt(Idx) != VNI)
476 continue;
477
478 // Follow sibling copies down the dominator tree.
479 if (Register DstReg = isFullCopyOf(MI, Reg)) {
480 if (isSibling(DstReg)) {
481 LiveInterval &DstLI = LIS.getInterval(DstReg);
482 VNInfo *DstVNI = DstLI.getVNInfoAt(Idx.getRegSlot());
483 assert(DstVNI && "Missing defined value")((void)0);
484 assert(DstVNI->def == Idx.getRegSlot() && "Wrong copy def slot")((void)0);
485 WorkList.push_back(std::make_pair(&DstLI, DstVNI));
486 }
487 continue;
488 }
489
490 // Erase spills.
491 int FI;
492 if (Reg == TII.isStoreToStackSlot(MI, FI) && FI == StackSlot) {
493 LLVM_DEBUG(dbgs() << "Redundant spill " << Idx << '\t' << MI)do { } while (false);
494 // eliminateDeadDefs won't normally remove stores, so switch opcode.
495 MI.setDesc(TII.get(TargetOpcode::KILL));
496 DeadDefs.push_back(&MI);
497 ++NumSpillsRemoved;
498 if (HSpiller.rmFromMergeableSpills(MI, StackSlot))
499 --NumSpills;
500 }
501 }
502 } while (!WorkList.empty());
503}
504
505//===----------------------------------------------------------------------===//
506// Rematerialization
507//===----------------------------------------------------------------------===//
508
509/// markValueUsed - Remember that VNI failed to rematerialize, so its defining
510/// instruction cannot be eliminated. See through snippet copies
511void InlineSpiller::markValueUsed(LiveInterval *LI, VNInfo *VNI) {
512 SmallVector<std::pair<LiveInterval*, VNInfo*>, 8> WorkList;
513 WorkList.push_back(std::make_pair(LI, VNI));
514 do {
515 std::tie(LI, VNI) = WorkList.pop_back_val();
516 if (!UsedValues.insert(VNI).second)
517 continue;
518
519 if (VNI->isPHIDef()) {
520 MachineBasicBlock *MBB = LIS.getMBBFromIndex(VNI->def);
521 for (MachineBasicBlock *P : MBB->predecessors()) {
522 VNInfo *PVNI = LI->getVNInfoBefore(LIS.getMBBEndIdx(P));
523 if (PVNI)
524 WorkList.push_back(std::make_pair(LI, PVNI));
525 }
526 continue;
527 }
528
529 // Follow snippet copies.
530 MachineInstr *MI = LIS.getInstructionFromIndex(VNI->def);
531 if (!SnippetCopies.count(MI))
532 continue;
533 LiveInterval &SnipLI = LIS.getInterval(MI->getOperand(1).getReg());
534 assert(isRegToSpill(SnipLI.reg()) && "Unexpected register in copy")((void)0);
535 VNInfo *SnipVNI = SnipLI.getVNInfoAt(VNI->def.getRegSlot(true));
536 assert(SnipVNI && "Snippet undefined before copy")((void)0);
537 WorkList.push_back(std::make_pair(&SnipLI, SnipVNI));
538 } while (!WorkList.empty());
539}
540
541bool InlineSpiller::canGuaranteeAssignmentAfterRemat(Register VReg,
542 MachineInstr &MI) {
543 if (!RestrictStatepointRemat)
544 return true;
545 // Here's a quick explanation of the problem we're trying to handle here:
546 // * There are some pseudo instructions with more vreg uses than there are
547 // physical registers on the machine.
548 // * This is normally handled by spilling the vreg, and folding the reload
549 // into the user instruction. (Thus decreasing the number of used vregs
550 // until the remainder can be assigned to physregs.)
551 // * However, since we may try to spill vregs in any order, we can end up
552 // trying to spill each operand to the instruction, and then rematting it
553 // instead. When that happens, the new live intervals (for the remats) are
554 // expected to be trivially assignable (i.e. RS_Done). However, since we
555 // may have more remats than physregs, we're guaranteed to fail to assign
556 // one.
557 // At the moment, we only handle this for STATEPOINTs since they're the only
558 // pseudo op where we've seen this. If we start seeing other instructions
559 // with the same problem, we need to revisit this.
560 if (MI.getOpcode() != TargetOpcode::STATEPOINT)
561 return true;
562 // For STATEPOINTs we allow re-materialization for fixed arguments only hoping
563 // that number of physical registers is enough to cover all fixed arguments.
564 // If it is not true we need to revisit it.
565 for (unsigned Idx = StatepointOpers(&MI).getVarIdx(),
566 EndIdx = MI.getNumOperands();
567 Idx < EndIdx; ++Idx) {
568 MachineOperand &MO = MI.getOperand(Idx);
569 if (MO.isReg() && MO.getReg() == VReg)
570 return false;
571 }
572 return true;
573}
574
575/// reMaterializeFor - Attempt to rematerialize before MI instead of reloading.
576bool InlineSpiller::reMaterializeFor(LiveInterval &VirtReg, MachineInstr &MI) {
577 // Analyze instruction
578 SmallVector<std::pair<MachineInstr *, unsigned>, 8> Ops;
579 VirtRegInfo RI = AnalyzeVirtRegInBundle(MI, VirtReg.reg(), &Ops);
580
581 if (!RI.Reads)
582 return false;
583
584 SlotIndex UseIdx = LIS.getInstructionIndex(MI).getRegSlot(true);
585 VNInfo *ParentVNI = VirtReg.getVNInfoAt(UseIdx.getBaseIndex());
586
587 if (!ParentVNI) {
588 LLVM_DEBUG(dbgs() << "\tadding <undef> flags: ")do { } while (false);
589 for (unsigned i = 0, e = MI.getNumOperands(); i != e; ++i) {
590 MachineOperand &MO = MI.getOperand(i);
591 if (MO.isReg() && MO.isUse() && MO.getReg() == VirtReg.reg())
592 MO.setIsUndef();
593 }
594 LLVM_DEBUG(dbgs() << UseIdx << '\t' << MI)do { } while (false);
595 return true;
596 }
597
598 if (SnippetCopies.count(&MI))
599 return false;
600
601 LiveInterval &OrigLI = LIS.getInterval(Original);
602 VNInfo *OrigVNI = OrigLI.getVNInfoAt(UseIdx);
603 LiveRangeEdit::Remat RM(ParentVNI);
604 RM.OrigMI = LIS.getInstructionFromIndex(OrigVNI->def);
605
606 if (!Edit->canRematerializeAt(RM, OrigVNI, UseIdx, false)) {
607 markValueUsed(&VirtReg, ParentVNI);
608 LLVM_DEBUG(dbgs() << "\tcannot remat for " << UseIdx << '\t' << MI)do { } while (false);
609 return false;
610 }
611
612 // If the instruction also writes VirtReg.reg, it had better not require the
613 // same register for uses and defs.
614 if (RI.Tied) {
615 markValueUsed(&VirtReg, ParentVNI);
616 LLVM_DEBUG(dbgs() << "\tcannot remat tied reg: " << UseIdx << '\t' << MI)do { } while (false);
617 return false;
618 }
619
620 // Before rematerializing into a register for a single instruction, try to
621 // fold a load into the instruction. That avoids allocating a new register.
622 if (RM.OrigMI->canFoldAsLoad() &&
623 foldMemoryOperand(Ops, RM.OrigMI)) {
624 Edit->markRematerialized(RM.ParentVNI);
625 ++NumFoldedLoads;
626 return true;
627 }
628
629 // If we can't guarantee that we'll be able to actually assign the new vreg,
630 // we can't remat.
631 if (!canGuaranteeAssignmentAfterRemat(VirtReg.reg(), MI)) {
632 markValueUsed(&VirtReg, ParentVNI);
633 LLVM_DEBUG(dbgs() << "\tcannot remat for " << UseIdx << '\t' << MI)do { } while (false);
634 return false;
635 }
636
637 // Allocate a new register for the remat.
638 Register NewVReg = Edit->createFrom(Original);
639
640 // Finally we can rematerialize OrigMI before MI.
641 SlotIndex DefIdx =
642 Edit->rematerializeAt(*MI.getParent(), MI, NewVReg, RM, TRI);
643
644 // We take the DebugLoc from MI, since OrigMI may be attributed to a
645 // different source location.
646 auto *NewMI = LIS.getInstructionFromIndex(DefIdx);
647 NewMI->setDebugLoc(MI.getDebugLoc());
648
649 (void)DefIdx;
650 LLVM_DEBUG(dbgs() << "\tremat: " << DefIdx << '\t'do { } while (false)
651 << *LIS.getInstructionFromIndex(DefIdx))do { } while (false);
652
653 // Replace operands
654 for (const auto &OpPair : Ops) {
655 MachineOperand &MO = OpPair.first->getOperand(OpPair.second);
656 if (MO.isReg() && MO.isUse() && MO.getReg() == VirtReg.reg()) {
657 MO.setReg(NewVReg);
658 MO.setIsKill();
659 }
660 }
661 LLVM_DEBUG(dbgs() << "\t " << UseIdx << '\t' << MI << '\n')do { } while (false);
662
663 ++NumRemats;
664 return true;
665}
666
667/// reMaterializeAll - Try to rematerialize as many uses as possible,
668/// and trim the live ranges after.
669void InlineSpiller::reMaterializeAll() {
670 if (!Edit->anyRematerializable(AA))
671 return;
672
673 UsedValues.clear();
674
675 // Try to remat before all uses of snippets.
676 bool anyRemat = false;
677 for (Register Reg : RegsToSpill) {
678 LiveInterval &LI = LIS.getInterval(Reg);
679 for (MachineRegisterInfo::reg_bundle_iterator
680 RegI = MRI.reg_bundle_begin(Reg), E = MRI.reg_bundle_end();
681 RegI != E; ) {
682 MachineInstr &MI = *RegI++;
683
684 // Debug values are not allowed to affect codegen.
685 if (MI.isDebugValue())
686 continue;
687
688 assert(!MI.isDebugInstr() && "Did not expect to find a use in debug "((void)0)
689 "instruction that isn't a DBG_VALUE")((void)0);
690
691 anyRemat |= reMaterializeFor(LI, MI);
692 }
693 }
694 if (!anyRemat)
695 return;
696
697 // Remove any values that were completely rematted.
698 for (Register Reg : RegsToSpill) {
699 LiveInterval &LI = LIS.getInterval(Reg);
700 for (LiveInterval::vni_iterator I = LI.vni_begin(), E = LI.vni_end();
701 I != E; ++I) {
702 VNInfo *VNI = *I;
703 if (VNI->isUnused() || VNI->isPHIDef() || UsedValues.count(VNI))
704 continue;
705 MachineInstr *MI = LIS.getInstructionFromIndex(VNI->def);
706 MI->addRegisterDead(Reg, &TRI);
707 if (!MI->allDefsAreDead())
708 continue;
709 LLVM_DEBUG(dbgs() << "All defs dead: " << *MI)do { } while (false);
710 DeadDefs.push_back(MI);
711 }
712 }
713
714 // Eliminate dead code after remat. Note that some snippet copies may be
715 // deleted here.
716 if (DeadDefs.empty())
717 return;
718 LLVM_DEBUG(dbgs() << "Remat created " << DeadDefs.size() << " dead defs.\n")do { } while (false);
719 Edit->eliminateDeadDefs(DeadDefs, RegsToSpill, AA);
720
721 // LiveRangeEdit::eliminateDeadDef is used to remove dead define instructions
722 // after rematerialization. To remove a VNI for a vreg from its LiveInterval,
723 // LiveIntervals::removeVRegDefAt is used. However, after non-PHI VNIs are all
724 // removed, PHI VNI are still left in the LiveInterval.
725 // So to get rid of unused reg, we need to check whether it has non-dbg
726 // reference instead of whether it has non-empty interval.
727 unsigned ResultPos = 0;
728 for (Register Reg : RegsToSpill) {
729 if (MRI.reg_nodbg_empty(Reg)) {
730 Edit->eraseVirtReg(Reg);
731 continue;
732 }
733
734 assert(LIS.hasInterval(Reg) &&((void)0)
735 (!LIS.getInterval(Reg).empty() || !MRI.reg_nodbg_empty(Reg)) &&((void)0)
736 "Empty and not used live-range?!")((void)0);
737
738 RegsToSpill[ResultPos++] = Reg;
739 }
740 RegsToSpill.erase(RegsToSpill.begin() + ResultPos, RegsToSpill.end());
741 LLVM_DEBUG(dbgs() << RegsToSpill.size()do { } while (false)
742 << " registers to spill after remat.\n")do { } while (false);
743}
744
745//===----------------------------------------------------------------------===//
746// Spilling
747//===----------------------------------------------------------------------===//
748
749/// If MI is a load or store of StackSlot, it can be removed.
750bool InlineSpiller::coalesceStackAccess(MachineInstr *MI, Register Reg) {
751 int FI = 0;
752 Register InstrReg = TII.isLoadFromStackSlot(*MI, FI);
753 bool IsLoad = InstrReg;
754 if (!IsLoad)
755 InstrReg = TII.isStoreToStackSlot(*MI, FI);
756
757 // We have a stack access. Is it the right register and slot?
758 if (InstrReg != Reg || FI != StackSlot)
759 return false;
760
761 if (!IsLoad)
762 HSpiller.rmFromMergeableSpills(*MI, StackSlot);
763
764 LLVM_DEBUG(dbgs() << "Coalescing stack access: " << *MI)do { } while (false);
765 LIS.RemoveMachineInstrFromMaps(*MI);
766 MI->eraseFromParent();
767
768 if (IsLoad) {
769 ++NumReloadsRemoved;
770 --NumReloads;
771 } else {
772 ++NumSpillsRemoved;
773 --NumSpills;
774 }
775
776 return true;
777}
778
779#if !defined(NDEBUG1) || defined(LLVM_ENABLE_DUMP)
780LLVM_DUMP_METHOD__attribute__((noinline))
781// Dump the range of instructions from B to E with their slot indexes.
782static void dumpMachineInstrRangeWithSlotIndex(MachineBasicBlock::iterator B,
783 MachineBasicBlock::iterator E,
784 LiveIntervals const &LIS,
785 const char *const header,
786 Register VReg = Register()) {
787 char NextLine = '\n';
788 char SlotIndent = '\t';
789
790 if (std::next(B) == E) {
791 NextLine = ' ';
792 SlotIndent = ' ';
793 }
794
795 dbgs() << '\t' << header << ": " << NextLine;
796
797 for (MachineBasicBlock::iterator I = B; I != E; ++I) {
798 SlotIndex Idx = LIS.getInstructionIndex(*I).getRegSlot();
799
800 // If a register was passed in and this instruction has it as a
801 // destination that is marked as an early clobber, print the
802 // early-clobber slot index.
803 if (VReg) {
804 MachineOperand *MO = I->findRegisterDefOperand(VReg);
805 if (MO && MO->isEarlyClobber())
806 Idx = Idx.getRegSlot(true);
807 }
808
809 dbgs() << SlotIndent << Idx << '\t' << *I;
810 }
811}
812#endif
813
814/// foldMemoryOperand - Try folding stack slot references in Ops into their
815/// instructions.
816///
817/// @param Ops Operand indices from AnalyzeVirtRegInBundle().
818/// @param LoadMI Load instruction to use instead of stack slot when non-null.
819/// @return True on success.
820bool InlineSpiller::
821foldMemoryOperand(ArrayRef<std::pair<MachineInstr *, unsigned>> Ops,
822 MachineInstr *LoadMI) {
823 if (Ops.empty())
824 return false;
825 // Don't attempt folding in bundles.
826 MachineInstr *MI = Ops.front().first;
827 if (Ops.back().first != MI || MI->isBundled())
828 return false;
829
830 bool WasCopy = MI->isCopy();
831 Register ImpReg;
832
833 // TII::foldMemoryOperand will do what we need here for statepoint
834 // (fold load into use and remove corresponding def). We will replace
835 // uses of removed def with loads (spillAroundUses).
836 // For that to work we need to untie def and use to pass it through
837 // foldMemoryOperand and signal foldPatchpoint that it is allowed to
838 // fold them.
839 bool UntieRegs = MI->getOpcode() == TargetOpcode::STATEPOINT;
840
841 // Spill subregs if the target allows it.
842 // We always want to spill subregs for stackmap/patchpoint pseudos.
843 bool SpillSubRegs = TII.isSubregFoldable() ||
844 MI->getOpcode() == TargetOpcode::STATEPOINT ||
845 MI->getOpcode() == TargetOpcode::PATCHPOINT ||
846 MI->getOpcode() == TargetOpcode::STACKMAP;
847
848 // TargetInstrInfo::foldMemoryOperand only expects explicit, non-tied
849 // operands.
850 SmallVector<unsigned, 8> FoldOps;
851 for (const auto &OpPair : Ops) {
852 unsigned Idx = OpPair.second;
853 assert(MI == OpPair.first && "Instruction conflict during operand folding")((void)0);
854 MachineOperand &MO = MI->getOperand(Idx);
855 if (MO.isImplicit()) {
856 ImpReg = MO.getReg();
857 continue;
858 }
859
860 if (!SpillSubRegs && MO.getSubReg())
861 return false;
862 // We cannot fold a load instruction into a def.
863 if (LoadMI && MO.isDef())
864 return false;
865 // Tied use operands should not be passed to foldMemoryOperand.
866 if (UntieRegs || !MI->isRegTiedToDefOperand(Idx))
867 FoldOps.push_back(Idx);
868 }
869
870 // If we only have implicit uses, we won't be able to fold that.
871 // Moreover, TargetInstrInfo::foldMemoryOperand will assert if we try!
872 if (FoldOps.empty())
873 return false;
874
875 MachineInstrSpan MIS(MI, MI->getParent());
876
877 SmallVector<std::pair<unsigned, unsigned> > TiedOps;
878 if (UntieRegs)
879 for (unsigned Idx : FoldOps) {
880 MachineOperand &MO = MI->getOperand(Idx);
881 if (!MO.isTied())
882 continue;
883 unsigned Tied = MI->findTiedOperandIdx(Idx);
884 if (MO.isUse())
885 TiedOps.emplace_back(Tied, Idx);
886 else {
887 assert(MO.isDef() && "Tied to not use and def?")((void)0);
888 TiedOps.emplace_back(Idx, Tied);
889 }
890 MI->untieRegOperand(Idx);
891 }
892
893 MachineInstr *FoldMI =
894 LoadMI ? TII.foldMemoryOperand(*MI, FoldOps, *LoadMI, &LIS)
895 : TII.foldMemoryOperand(*MI, FoldOps, StackSlot, &LIS, &VRM);
896 if (!FoldMI) {
897 // Re-tie operands.
898 for (auto Tied : TiedOps)
899 MI->tieOperands(Tied.first, Tied.second);
900 return false;
901 }
902
903 // Remove LIS for any dead defs in the original MI not in FoldMI.
904 for (MIBundleOperands MO(*MI); MO.isValid(); ++MO) {
905 if (!MO->isReg())
906 continue;
907 Register Reg = MO->getReg();
908 if (!Reg || Register::isVirtualRegister(Reg) || MRI.isReserved(Reg)) {
909 continue;
910 }
911 // Skip non-Defs, including undef uses and internal reads.
912 if (MO->isUse())
913 continue;
914 PhysRegInfo RI = AnalyzePhysRegInBundle(*FoldMI, Reg, &TRI);
915 if (RI.FullyDefined)
916 continue;
917 // FoldMI does not define this physreg. Remove the LI segment.
918 assert(MO->isDead() && "Cannot fold physreg def")((void)0);
919 SlotIndex Idx = LIS.getInstructionIndex(*MI).getRegSlot();
920 LIS.removePhysRegDefAt(Reg.asMCReg(), Idx);
921 }
922
923 int FI;
924 if (TII.isStoreToStackSlot(*MI, FI) &&
925 HSpiller.rmFromMergeableSpills(*MI, FI))
926 --NumSpills;
927 LIS.ReplaceMachineInstrInMaps(*MI, *FoldMI);
928 // Update the call site info.
929 if (MI->isCandidateForCallSiteEntry())
930 MI->getMF()->moveCallSiteInfo(MI, FoldMI);
931 MI->eraseFromParent();
932
933 // Insert any new instructions other than FoldMI into the LIS maps.
934 assert(!MIS.empty() && "Unexpected empty span of instructions!")((void)0);
935 for (MachineInstr &MI : MIS)
936 if (&MI != FoldMI)
937 LIS.InsertMachineInstrInMaps(MI);
938
939 // TII.foldMemoryOperand may have left some implicit operands on the
940 // instruction. Strip them.
941 if (ImpReg)
942 for (unsigned i = FoldMI->getNumOperands(); i; --i) {
943 MachineOperand &MO = FoldMI->getOperand(i - 1);
944 if (!MO.isReg() || !MO.isImplicit())
945 break;
946 if (MO.getReg() == ImpReg)
947 FoldMI->RemoveOperand(i - 1);
948 }
949
950 LLVM_DEBUG(dumpMachineInstrRangeWithSlotIndex(MIS.begin(), MIS.end(), LIS,do { } while (false)
951 "folded"))do { } while (false);
952
953 if (!WasCopy)
954 ++NumFolded;
955 else if (Ops.front().second == 0) {
956 ++NumSpills;
957 // If there is only 1 store instruction is required for spill, add it
958 // to mergeable list. In X86 AMX, 2 intructions are required to store.
959 // We disable the merge for this case.
960 if (std::distance(MIS.begin(), MIS.end()) <= 1)
961 HSpiller.addToMergeableSpills(*FoldMI, StackSlot, Original);
962 } else
963 ++NumReloads;
964 return true;
965}
966
967void InlineSpiller::insertReload(Register NewVReg,
968 SlotIndex Idx,
969 MachineBasicBlock::iterator MI) {
970 MachineBasicBlock &MBB = *MI->getParent();
971
972 MachineInstrSpan MIS(MI, &MBB);
973 TII.loadRegFromStackSlot(MBB, MI, NewVReg, StackSlot,
974 MRI.getRegClass(NewVReg), &TRI);
975
976 LIS.InsertMachineInstrRangeInMaps(MIS.begin(), MI);
977
978 LLVM_DEBUG(dumpMachineInstrRangeWithSlotIndex(MIS.begin(), MI, LIS, "reload",do { } while (false)
979 NewVReg))do { } while (false);
980 ++NumReloads;
981}
982
983/// Check if \p Def fully defines a VReg with an undefined value.
984/// If that's the case, that means the value of VReg is actually
985/// not relevant.
986static bool isRealSpill(const MachineInstr &Def) {
987 if (!Def.isImplicitDef())
988 return true;
989 assert(Def.getNumOperands() == 1 &&((void)0)
990 "Implicit def with more than one definition")((void)0);
991 // We can say that the VReg defined by Def is undef, only if it is
992 // fully defined by Def. Otherwise, some of the lanes may not be
993 // undef and the value of the VReg matters.
994 return Def.getOperand(0).getSubReg();
995}
996
997/// insertSpill - Insert a spill of NewVReg after MI.
998void InlineSpiller::insertSpill(Register NewVReg, bool isKill,
999 MachineBasicBlock::iterator MI) {
1000 // Spill are not terminators, so inserting spills after terminators will
1001 // violate invariants in MachineVerifier.
1002 assert(!MI->isTerminator() && "Inserting a spill after a terminator")((void)0);
1003 MachineBasicBlock &MBB = *MI->getParent();
1004
1005 MachineInstrSpan MIS(MI, &MBB);
1006 MachineBasicBlock::iterator SpillBefore = std::next(MI);
1007 bool IsRealSpill = isRealSpill(*MI);
1008
1009 if (IsRealSpill)
1010 TII.storeRegToStackSlot(MBB, SpillBefore, NewVReg, isKill, StackSlot,
1011 MRI.getRegClass(NewVReg), &TRI);
1012 else
1013 // Don't spill undef value.
1014 // Anything works for undef, in particular keeping the memory
1015 // uninitialized is a viable option and it saves code size and
1016 // run time.
1017 BuildMI(MBB, SpillBefore, MI->getDebugLoc(), TII.get(TargetOpcode::KILL))
1018 .addReg(NewVReg, getKillRegState(isKill));
1019
1020 MachineBasicBlock::iterator Spill = std::next(MI);
1021 LIS.InsertMachineInstrRangeInMaps(Spill, MIS.end());
1022 for (const MachineInstr &MI : make_range(Spill, MIS.end()))
1023 getVDefInterval(MI, LIS);
1024
1025 LLVM_DEBUG(do { } while (false)
1026 dumpMachineInstrRangeWithSlotIndex(Spill, MIS.end(), LIS, "spill"))do { } while (false);
1027 ++NumSpills;
1028 // If there is only 1 store instruction is required for spill, add it
1029 // to mergeable list. In X86 AMX, 2 intructions are required to store.
1030 // We disable the merge for this case.
1031 if (IsRealSpill && std::distance(Spill, MIS.end()) <= 1)
1032 HSpiller.addToMergeableSpills(*Spill, StackSlot, Original);
1033}
1034
1035/// spillAroundUses - insert spill code around each use of Reg.
1036void InlineSpiller::spillAroundUses(Register Reg) {
1037 LLVM_DEBUG(dbgs() << "spillAroundUses " << printReg(Reg) << '\n')do { } while (false);
1038 LiveInterval &OldLI = LIS.getInterval(Reg);
1039
1040 // Iterate over instructions using Reg.
1041 for (MachineRegisterInfo::reg_bundle_iterator
1042 RegI = MRI.reg_bundle_begin(Reg), E = MRI.reg_bundle_end();
1043 RegI != E; ) {
1044 MachineInstr *MI = &*(RegI++);
1045
1046 // Debug values are not allowed to affect codegen.
1047 if (MI->isDebugValue()) {
1048 // Modify DBG_VALUE now that the value is in a spill slot.
1049 MachineBasicBlock *MBB = MI->getParent();
1050 LLVM_DEBUG(dbgs() << "Modifying debug info due to spill:\t" << *MI)do { } while (false);
1051 buildDbgValueForSpill(*MBB, MI, *MI, StackSlot, Reg);
1052 MBB->erase(MI);
1053 continue;
1054 }
1055
1056 assert(!MI->isDebugInstr() && "Did not expect to find a use in debug "((void)0)
1057 "instruction that isn't a DBG_VALUE")((void)0);
1058
1059 // Ignore copies to/from snippets. We'll delete them.
1060 if (SnippetCopies.count(MI))
1061 continue;
1062
1063 // Stack slot accesses may coalesce away.
1064 if (coalesceStackAccess(MI, Reg))
1065 continue;
1066
1067 // Analyze instruction.
1068 SmallVector<std::pair<MachineInstr*, unsigned>, 8> Ops;
1069 VirtRegInfo RI = AnalyzeVirtRegInBundle(*MI, Reg, &Ops);
1070
1071 // Find the slot index where this instruction reads and writes OldLI.
1072 // This is usually the def slot, except for tied early clobbers.
1073 SlotIndex Idx = LIS.getInstructionIndex(*MI).getRegSlot();
1074 if (VNInfo *VNI = OldLI.getVNInfoAt(Idx.getRegSlot(true)))
1075 if (SlotIndex::isSameInstr(Idx, VNI->def))
1076 Idx = VNI->def;
1077
1078 // Check for a sibling copy.
1079 Register SibReg = isFullCopyOf(*MI, Reg);
1080 if (SibReg && isSibling(SibReg)) {
1081 // This may actually be a copy between snippets.
1082 if (isRegToSpill(SibReg)) {
1083 LLVM_DEBUG(dbgs() << "Found new snippet copy: " << *MI)do { } while (false);
1084 SnippetCopies.insert(MI);
1085 continue;
1086 }
1087 if (RI.Writes) {
1088 if (hoistSpillInsideBB(OldLI, *MI)) {
1089 // This COPY is now dead, the value is already in the stack slot.
1090 MI->getOperand(0).setIsDead();
1091 DeadDefs.push_back(MI);
1092 continue;
1093 }
1094 } else {
1095 // This is a reload for a sib-reg copy. Drop spills downstream.
1096 LiveInterval &SibLI = LIS.getInterval(SibReg);
1097 eliminateRedundantSpills(SibLI, SibLI.getVNInfoAt(Idx));
1098 // The COPY will fold to a reload below.
1099 }
1100 }
1101
1102 // Attempt to fold memory ops.
1103 if (foldMemoryOperand(Ops))
1104 continue;
1105
1106 // Create a new virtual register for spill/fill.
1107 // FIXME: Infer regclass from instruction alone.
1108 Register NewVReg = Edit->createFrom(Reg);
1109
1110 if (RI.Reads)
1111 insertReload(NewVReg, Idx, MI);
1112
1113 // Rewrite instruction operands.
1114 bool hasLiveDef = false;
1115 for (const auto &OpPair : Ops) {
1116 MachineOperand &MO = OpPair.first->getOperand(OpPair.second);
1117 MO.setReg(NewVReg);
1118 if (MO.isUse()) {
1119 if (!OpPair.first->isRegTiedToDefOperand(OpPair.second))
1120 MO.setIsKill();
1121 } else {
1122 if (!MO.isDead())
1123 hasLiveDef = true;
1124 }
1125 }
1126 LLVM_DEBUG(dbgs() << "\trewrite: " << Idx << '\t' << *MI << '\n')do { } while (false);
1127
1128 // FIXME: Use a second vreg if instruction has no tied ops.
1129 if (RI.Writes)
1130 if (hasLiveDef)
1131 insertSpill(NewVReg, true, MI);
1132 }
1133}
1134
1135/// spillAll - Spill all registers remaining after rematerialization.
1136void InlineSpiller::spillAll() {
1137 // Update LiveStacks now that we are committed to spilling.
1138 if (StackSlot == VirtRegMap::NO_STACK_SLOT) {
1139 StackSlot = VRM.assignVirt2StackSlot(Original);
1140 StackInt = &LSS.getOrCreateInterval(StackSlot, MRI.getRegClass(Original));
1141 StackInt->getNextValue(SlotIndex(), LSS.getVNInfoAllocator());
1142 } else
1143 StackInt = &LSS.getInterval(StackSlot);
1144
1145 if (Original != Edit->getReg())
1146 VRM.assignVirt2StackSlot(Edit->getReg(), StackSlot);
1147
1148 assert(StackInt->getNumValNums() == 1 && "Bad stack interval values")((void)0);
1149 for (Register Reg : RegsToSpill)
1150 StackInt->MergeSegmentsInAsValue(LIS.getInterval(Reg),
1151 StackInt->getValNumInfo(0));
1152 LLVM_DEBUG(dbgs() << "Merged spilled regs: " << *StackInt << '\n')do { } while (false);
1153
1154 // Spill around uses of all RegsToSpill.
1155 for (Register Reg : RegsToSpill)
1156 spillAroundUses(Reg);
1157
1158 // Hoisted spills may cause dead code.
1159 if (!DeadDefs.empty()) {
1160 LLVM_DEBUG(dbgs() << "Eliminating " << DeadDefs.size() << " dead defs\n")do { } while (false);
1161 Edit->eliminateDeadDefs(DeadDefs, RegsToSpill, AA);
1162 }
1163
1164 // Finally delete the SnippetCopies.
1165 for (Register Reg : RegsToSpill) {
1166 for (MachineRegisterInfo::reg_instr_iterator
1167 RI = MRI.reg_instr_begin(Reg), E = MRI.reg_instr_end();
1168 RI != E; ) {
1169 MachineInstr &MI = *(RI++);
1170 assert(SnippetCopies.count(&MI) && "Remaining use wasn't a snippet copy")((void)0);
1171 // FIXME: Do this with a LiveRangeEdit callback.
1172 LIS.RemoveMachineInstrFromMaps(MI);
1173 MI.eraseFromParent();
1174 }
1175 }
1176
1177 // Delete all spilled registers.
1178 for (Register Reg : RegsToSpill)
1179 Edit->eraseVirtReg(Reg);
1180}
1181
1182void InlineSpiller::spill(LiveRangeEdit &edit) {
1183 ++NumSpilledRanges;
1184 Edit = &edit;
1185 assert(!Register::isStackSlot(edit.getReg()) &&((void)0)
1186 "Trying to spill a stack slot.")((void)0);
1187 // Share a stack slot among all descendants of Original.
1188 Original = VRM.getOriginal(edit.getReg());
1189 StackSlot = VRM.getStackSlot(Original);
1190 StackInt = nullptr;
1191
1192 LLVM_DEBUG(dbgs() << "Inline spilling "do { } while (false)
1193 << TRI.getRegClassName(MRI.getRegClass(edit.getReg()))do { } while (false)
1194 << ':' << edit.getParent() << "\nFrom original "do { } while (false)
1195 << printReg(Original) << '\n')do { } while (false);
1196 assert(edit.getParent().isSpillable() &&((void)0)
1197 "Attempting to spill already spilled value.")((void)0);
1198 assert(DeadDefs.empty() && "Previous spill didn't remove dead defs")((void)0);
1199
1200 collectRegsToSpill();
1201 reMaterializeAll();
1202
1203 // Remat may handle everything.
1204 if (!RegsToSpill.empty())
1205 spillAll();
1206
1207 Edit->calculateRegClassAndHint(MF, VRAI);
1208}
1209
1210/// Optimizations after all the reg selections and spills are done.
1211void InlineSpiller::postOptimization() { HSpiller.hoistAllSpills(); }
1
Calling 'HoistSpillHelper::hoistAllSpills'
1212
1213/// When a spill is inserted, add the spill to MergeableSpills map.
1214void HoistSpillHelper::addToMergeableSpills(MachineInstr &Spill, int StackSlot,
1215 unsigned Original) {
1216 BumpPtrAllocator &Allocator = LIS.getVNInfoAllocator();
1217 LiveInterval &OrigLI = LIS.getInterval(Original);
1218 // save a copy of LiveInterval in StackSlotToOrigLI because the original
1219 // LiveInterval may be cleared after all its references are spilled.
1220 if (StackSlotToOrigLI.find(StackSlot) == StackSlotToOrigLI.end()) {
1221 auto LI = std::make_unique<LiveInterval>(OrigLI.reg(), OrigLI.weight());
1222 LI->assign(OrigLI, Allocator);
1223 StackSlotToOrigLI[StackSlot] = std::move(LI);
1224 }
1225 SlotIndex Idx = LIS.getInstructionIndex(Spill);
1226 VNInfo *OrigVNI = StackSlotToOrigLI[StackSlot]->getVNInfoAt(Idx.getRegSlot());
1227 std::pair<int, VNInfo *> MIdx = std::make_pair(StackSlot, OrigVNI);
1228 MergeableSpills[MIdx].insert(&Spill);
1229}
1230
1231/// When a spill is removed, remove the spill from MergeableSpills map.
1232/// Return true if the spill is removed successfully.
1233bool HoistSpillHelper::rmFromMergeableSpills(MachineInstr &Spill,
1234 int StackSlot) {
1235 auto It = StackSlotToOrigLI.find(StackSlot);
1236 if (It == StackSlotToOrigLI.end())
1237 return false;
1238 SlotIndex Idx = LIS.getInstructionIndex(Spill);
1239 VNInfo *OrigVNI = It->second->getVNInfoAt(Idx.getRegSlot());
1240 std::pair<int, VNInfo *> MIdx = std::make_pair(StackSlot, OrigVNI);
1241 return MergeableSpills[MIdx].erase(&Spill);
1242}
1243
1244/// Check BB to see if it is a possible target BB to place a hoisted spill,
1245/// i.e., there should be a living sibling of OrigReg at the insert point.
1246bool HoistSpillHelper::isSpillCandBB(LiveInterval &OrigLI, VNInfo &OrigVNI,
1247 MachineBasicBlock &BB, Register &LiveReg) {
1248 SlotIndex Idx = IPA.getLastInsertPoint(OrigLI, BB);
1249 // The original def could be after the last insert point in the root block,
1250 // we can't hoist to here.
1251 if (Idx < OrigVNI.def) {
1252 // TODO: We could be better here. If LI is not alive in landing pad
1253 // we could hoist spill after LIP.
1254 LLVM_DEBUG(dbgs() << "can't spill in root block - def after LIP\n")do { } while (false);
1255 return false;
1256 }
1257 Register OrigReg = OrigLI.reg();
1258 SmallSetVector<Register, 16> &Siblings = Virt2SiblingsMap[OrigReg];
1259 assert(OrigLI.getVNInfoAt(Idx) == &OrigVNI && "Unexpected VNI")((void)0);
1260
1261 for (const Register &SibReg : Siblings) {
1262 LiveInterval &LI = LIS.getInterval(SibReg);
1263 VNInfo *VNI = LI.getVNInfoAt(Idx);
1264 if (VNI) {
1265 LiveReg = SibReg;
1266 return true;
1267 }
1268 }
1269 return false;
1270}
1271
1272/// Remove redundant spills in the same BB. Save those redundant spills in
1273/// SpillsToRm, and save the spill to keep and its BB in SpillBBToSpill map.
1274void HoistSpillHelper::rmRedundantSpills(
1275 SmallPtrSet<MachineInstr *, 16> &Spills,
1276 SmallVectorImpl<MachineInstr *> &SpillsToRm,
1277 DenseMap<MachineDomTreeNode *, MachineInstr *> &SpillBBToSpill) {
1278 // For each spill saw, check SpillBBToSpill[] and see if its BB already has
1279 // another spill inside. If a BB contains more than one spill, only keep the
1280 // earlier spill with smaller SlotIndex.
1281 for (const auto CurrentSpill : Spills) {
1282 MachineBasicBlock *Block = CurrentSpill->getParent();
1283 MachineDomTreeNode *Node = MDT.getBase().getNode(Block);
1284 MachineInstr *PrevSpill = SpillBBToSpill[Node];
1285 if (PrevSpill) {
1286 SlotIndex PIdx = LIS.getInstructionIndex(*PrevSpill);
1287 SlotIndex CIdx = LIS.getInstructionIndex(*CurrentSpill);
1288 MachineInstr *SpillToRm = (CIdx > PIdx) ? CurrentSpill : PrevSpill;
1289 MachineInstr *SpillToKeep = (CIdx > PIdx) ? PrevSpill : CurrentSpill;
1290 SpillsToRm.push_back(SpillToRm);
1291 SpillBBToSpill[MDT.getBase().getNode(Block)] = SpillToKeep;
1292 } else {
1293 SpillBBToSpill[MDT.getBase().getNode(Block)] = CurrentSpill;
1294 }
1295 }
1296 for (const auto SpillToRm : SpillsToRm)
1297 Spills.erase(SpillToRm);
1298}
1299
1300/// Starting from \p Root find a top-down traversal order of the dominator
1301/// tree to visit all basic blocks containing the elements of \p Spills.
1302/// Redundant spills will be found and put into \p SpillsToRm at the same
1303/// time. \p SpillBBToSpill will be populated as part of the process and
1304/// maps a basic block to the first store occurring in the basic block.
1305/// \post SpillsToRm.union(Spills\@post) == Spills\@pre
1306void HoistSpillHelper::getVisitOrders(
1307 MachineBasicBlock *Root, SmallPtrSet<MachineInstr *, 16> &Spills,
1308 SmallVectorImpl<MachineDomTreeNode *> &Orders,
1309 SmallVectorImpl<MachineInstr *> &SpillsToRm,
1310 DenseMap<MachineDomTreeNode *, unsigned> &SpillsToKeep,
1311 DenseMap<MachineDomTreeNode *, MachineInstr *> &SpillBBToSpill) {
1312 // The set contains all the possible BB nodes to which we may hoist
1313 // original spills.
1314 SmallPtrSet<MachineDomTreeNode *, 8> WorkSet;
1315 // Save the BB nodes on the path from the first BB node containing
1316 // non-redundant spill to the Root node.
1317 SmallPtrSet<MachineDomTreeNode *, 8> NodesOnPath;
1318 // All the spills to be hoisted must originate from a single def instruction
1319 // to the OrigReg. It means the def instruction should dominate all the spills
1320 // to be hoisted. We choose the BB where the def instruction is located as
1321 // the Root.
1322 MachineDomTreeNode *RootIDomNode = MDT[Root]->getIDom();
1323 // For every node on the dominator tree with spill, walk up on the dominator
1324 // tree towards the Root node until it is reached. If there is other node
1325 // containing spill in the middle of the path, the previous spill saw will
1326 // be redundant and the node containing it will be removed. All the nodes on
1327 // the path starting from the first node with non-redundant spill to the Root
1328 // node will be added to the WorkSet, which will contain all the possible
1329 // locations where spills may be hoisted to after the loop below is done.
1330 for (const auto Spill : Spills) {
1331 MachineBasicBlock *Block = Spill->getParent();
1332 MachineDomTreeNode *Node = MDT[Block];
8
Calling 'MachineDominatorTree::operator[]'
21
Returning from 'MachineDominatorTree::operator[]'
22
'Node' initialized here
1333 MachineInstr *SpillToRm = nullptr;
1334 while (Node != RootIDomNode) {
23
Assuming 'Node' is not equal to 'RootIDomNode'
24
Loop condition is true. Entering loop body
1335 // If Node dominates Block, and it already contains a spill, the spill in
1336 // Block will be redundant.
1337 if (Node != MDT[Block] && SpillBBToSpill[Node]) {
25
Assuming the condition is false
26
Assuming pointer value is null
1338 SpillToRm = SpillBBToSpill[MDT[Block]];
1339 break;
1340 /// If we see the Node already in WorkSet, the path from the Node to
1341 /// the Root node must already be traversed by another spill.
1342 /// Then no need to repeat.
1343 } else if (WorkSet.count(Node)) {
27
Assuming the condition is false
28
Taking false branch
1344 break;
1345 } else {
1346 NodesOnPath.insert(Node);
1347 }
1348 Node = Node->getIDom();
29
Called C++ object pointer is null
1349 }
1350 if (SpillToRm) {
1351 SpillsToRm.push_back(SpillToRm);
1352 } else {
1353 // Add a BB containing the original spills to SpillsToKeep -- i.e.,
1354 // set the initial status before hoisting start. The value of BBs
1355 // containing original spills is set to 0, in order to descriminate
1356 // with BBs containing hoisted spills which will be inserted to
1357 // SpillsToKeep later during hoisting.
1358 SpillsToKeep[MDT[Block]] = 0;
1359 WorkSet.insert(NodesOnPath.begin(), NodesOnPath.end());
1360 }
1361 NodesOnPath.clear();
1362 }
1363
1364 // Sort the nodes in WorkSet in top-down order and save the nodes
1365 // in Orders. Orders will be used for hoisting in runHoistSpills.
1366 unsigned idx = 0;
1367 Orders.push_back(MDT.getBase().getNode(Root));
1368 do {
1369 MachineDomTreeNode *Node = Orders[idx++];
1370 for (MachineDomTreeNode *Child : Node->children()) {
1371 if (WorkSet.count(Child))
1372 Orders.push_back(Child);
1373 }
1374 } while (idx != Orders.size());
1375 assert(Orders.size() == WorkSet.size() &&((void)0)
1376 "Orders have different size with WorkSet")((void)0);
1377
1378#ifndef NDEBUG1
1379 LLVM_DEBUG(dbgs() << "Orders size is " << Orders.size() << "\n")do { } while (false);
1380 SmallVector<MachineDomTreeNode *, 32>::reverse_iterator RIt = Orders.rbegin();
1381 for (; RIt != Orders.rend(); RIt++)
1382 LLVM_DEBUG(dbgs() << "BB" << (*RIt)->getBlock()->getNumber() << ",")do { } while (false);
1383 LLVM_DEBUG(dbgs() << "\n")do { } while (false);
1384#endif
1385}
1386
1387/// Try to hoist spills according to BB hotness. The spills to removed will
1388/// be saved in \p SpillsToRm. The spills to be inserted will be saved in
1389/// \p SpillsToIns.
1390void HoistSpillHelper::runHoistSpills(
1391 LiveInterval &OrigLI, VNInfo &OrigVNI,
1392 SmallPtrSet<MachineInstr *, 16> &Spills,
1393 SmallVectorImpl<MachineInstr *> &SpillsToRm,
1394 DenseMap<MachineBasicBlock *, unsigned> &SpillsToIns) {
1395 // Visit order of dominator tree nodes.
1396 SmallVector<MachineDomTreeNode *, 32> Orders;
1397 // SpillsToKeep contains all the nodes where spills are to be inserted
1398 // during hoisting. If the spill to be inserted is an original spill
1399 // (not a hoisted one), the value of the map entry is 0. If the spill
1400 // is a hoisted spill, the value of the map entry is the VReg to be used
1401 // as the source of the spill.
1402 DenseMap<MachineDomTreeNode *, unsigned> SpillsToKeep;
1403 // Map from BB to the first spill inside of it.
1404 DenseMap<MachineDomTreeNode *, MachineInstr *> SpillBBToSpill;
1405
1406 rmRedundantSpills(Spills, SpillsToRm, SpillBBToSpill);
1407
1408 MachineBasicBlock *Root = LIS.getMBBFromIndex(OrigVNI.def);
1409 getVisitOrders(Root, Spills, Orders, SpillsToRm, SpillsToKeep,
7
Calling 'HoistSpillHelper::getVisitOrders'
1410 SpillBBToSpill);
1411
1412 // SpillsInSubTreeMap keeps the map from a dom tree node to a pair of
1413 // nodes set and the cost of all the spills inside those nodes.
1414 // The nodes set are the locations where spills are to be inserted
1415 // in the subtree of current node.
1416 using NodesCostPair =
1417 std::pair<SmallPtrSet<MachineDomTreeNode *, 16>, BlockFrequency>;
1418 DenseMap<MachineDomTreeNode *, NodesCostPair> SpillsInSubTreeMap;
1419
1420 // Iterate Orders set in reverse order, which will be a bottom-up order
1421 // in the dominator tree. Once we visit a dom tree node, we know its
1422 // children have already been visited and the spill locations in the
1423 // subtrees of all the children have been determined.
1424 SmallVector<MachineDomTreeNode *, 32>::reverse_iterator RIt = Orders.rbegin();
1425 for (; RIt != Orders.rend(); RIt++) {
1426 MachineBasicBlock *Block = (*RIt)->getBlock();
1427
1428 // If Block contains an original spill, simply continue.
1429 if (SpillsToKeep.find(*RIt) != SpillsToKeep.end() && !SpillsToKeep[*RIt]) {
1430 SpillsInSubTreeMap[*RIt].first.insert(*RIt);
1431 // SpillsInSubTreeMap[*RIt].second contains the cost of spill.
1432 SpillsInSubTreeMap[*RIt].second = MBFI.getBlockFreq(Block);
1433 continue;
1434 }
1435
1436 // Collect spills in subtree of current node (*RIt) to
1437 // SpillsInSubTreeMap[*RIt].first.
1438 for (MachineDomTreeNode *Child : (*RIt)->children()) {
1439 if (SpillsInSubTreeMap.find(Child) == SpillsInSubTreeMap.end())
1440 continue;
1441 // The stmt "SpillsInSubTree = SpillsInSubTreeMap[*RIt].first" below
1442 // should be placed before getting the begin and end iterators of
1443 // SpillsInSubTreeMap[Child].first, or else the iterators may be
1444 // invalidated when SpillsInSubTreeMap[*RIt] is seen the first time
1445 // and the map grows and then the original buckets in the map are moved.
1446 SmallPtrSet<MachineDomTreeNode *, 16> &SpillsInSubTree =
1447 SpillsInSubTreeMap[*RIt].first;
1448 BlockFrequency &SubTreeCost = SpillsInSubTreeMap[*RIt].second;
1449 SubTreeCost += SpillsInSubTreeMap[Child].second;
1450 auto BI = SpillsInSubTreeMap[Child].first.begin();
1451 auto EI = SpillsInSubTreeMap[Child].first.end();
1452 SpillsInSubTree.insert(BI, EI);
1453 SpillsInSubTreeMap.erase(Child);
1454 }
1455
1456 SmallPtrSet<MachineDomTreeNode *, 16> &SpillsInSubTree =
1457 SpillsInSubTreeMap[*RIt].first;
1458 BlockFrequency &SubTreeCost = SpillsInSubTreeMap[*RIt].second;
1459 // No spills in subtree, simply continue.
1460 if (SpillsInSubTree.empty())
1461 continue;
1462
1463 // Check whether Block is a possible candidate to insert spill.
1464 Register LiveReg;
1465 if (!isSpillCandBB(OrigLI, OrigVNI, *Block, LiveReg))
1466 continue;
1467
1468 // If there are multiple spills that could be merged, bias a little
1469 // to hoist the spill.
1470 BranchProbability MarginProb = (SpillsInSubTree.size() > 1)
1471 ? BranchProbability(9, 10)
1472 : BranchProbability(1, 1);
1473 if (SubTreeCost > MBFI.getBlockFreq(Block) * MarginProb) {
1474 // Hoist: Move spills to current Block.
1475 for (const auto SpillBB : SpillsInSubTree) {
1476 // When SpillBB is a BB contains original spill, insert the spill
1477 // to SpillsToRm.
1478 if (SpillsToKeep.find(SpillBB) != SpillsToKeep.end() &&
1479 !SpillsToKeep[SpillBB]) {
1480 MachineInstr *SpillToRm = SpillBBToSpill[SpillBB];
1481 SpillsToRm.push_back(SpillToRm);
1482 }
1483 // SpillBB will not contain spill anymore, remove it from SpillsToKeep.
1484 SpillsToKeep.erase(SpillBB);
1485 }
1486 // Current Block is the BB containing the new hoisted spill. Add it to
1487 // SpillsToKeep. LiveReg is the source of the new spill.
1488 SpillsToKeep[*RIt] = LiveReg;
1489 LLVM_DEBUG({do { } while (false)
1490 dbgs() << "spills in BB: ";do { } while (false)
1491 for (const auto Rspill : SpillsInSubTree)do { } while (false)
1492 dbgs() << Rspill->getBlock()->getNumber() << " ";do { } while (false)
1493 dbgs() << "were promoted to BB" << (*RIt)->getBlock()->getNumber()do { } while (false)
1494 << "\n";do { } while (false)
1495 })do { } while (false);
1496 SpillsInSubTree.clear();
1497 SpillsInSubTree.insert(*RIt);
1498 SubTreeCost = MBFI.getBlockFreq(Block);
1499 }
1500 }
1501 // For spills in SpillsToKeep with LiveReg set (i.e., not original spill),
1502 // save them to SpillsToIns.
1503 for (const auto &Ent : SpillsToKeep) {
1504 if (Ent.second)
1505 SpillsToIns[Ent.first->getBlock()] = Ent.second;
1506 }
1507}
1508
1509/// For spills with equal values, remove redundant spills and hoist those left
1510/// to less hot spots.
1511///
1512/// Spills with equal values will be collected into the same set in
1513/// MergeableSpills when spill is inserted. These equal spills are originated
1514/// from the same defining instruction and are dominated by the instruction.
1515/// Before hoisting all the equal spills, redundant spills inside in the same
1516/// BB are first marked to be deleted. Then starting from the spills left, walk
1517/// up on the dominator tree towards the Root node where the define instruction
1518/// is located, mark the dominated spills to be deleted along the way and
1519/// collect the BB nodes on the path from non-dominated spills to the define
1520/// instruction into a WorkSet. The nodes in WorkSet are the candidate places
1521/// where we are considering to hoist the spills. We iterate the WorkSet in
1522/// bottom-up order, and for each node, we will decide whether to hoist spills
1523/// inside its subtree to that node. In this way, we can get benefit locally
1524/// even if hoisting all the equal spills to one cold place is impossible.
1525void HoistSpillHelper::hoistAllSpills() {
1526 SmallVector<Register, 4> NewVRegs;
1527 LiveRangeEdit Edit(nullptr, NewVRegs, MF, LIS, &VRM, this);
1528
1529 for (unsigned i = 0, e = MRI.getNumVirtRegs(); i != e; ++i) {
2
Assuming 'i' is equal to 'e'
3
Loop condition is false. Execution continues on line 1537
1530 Register Reg = Register::index2VirtReg(i);
1531 Register Original = VRM.getPreSplitReg(Reg);
1532 if (!MRI.def_empty(Reg))
1533 Virt2SiblingsMap[Original].insert(Reg);
1534 }
1535
1536 // Each entry in MergeableSpills contains a spill set with equal values.
1537 for (auto &Ent : MergeableSpills) {
1538 int Slot = Ent.first.first;
1539 LiveInterval &OrigLI = *StackSlotToOrigLI[Slot];
1540 VNInfo *OrigVNI = Ent.first.second;
1541 SmallPtrSet<MachineInstr *, 16> &EqValSpills = Ent.second;
1542 if (Ent.second.empty())
4
Taking false branch
1543 continue;
1544
1545 LLVM_DEBUG({do { } while (false)
5
Loop condition is false. Exiting loop
1546 dbgs() << "\nFor Slot" << Slot << " and VN" << OrigVNI->id << ":\n"do { } while (false)
1547 << "Equal spills in BB: ";do { } while (false)
1548 for (const auto spill : EqValSpills)do { } while (false)
1549 dbgs() << spill->getParent()->getNumber() << " ";do { } while (false)
1550 dbgs() << "\n";do { } while (false)
1551 })do { } while (false);
1552
1553 // SpillsToRm is the spill set to be removed from EqValSpills.
1554 SmallVector<MachineInstr *, 16> SpillsToRm;
1555 // SpillsToIns is the spill set to be newly inserted after hoisting.
1556 DenseMap<MachineBasicBlock *, unsigned> SpillsToIns;
1557
1558 runHoistSpills(OrigLI, *OrigVNI, EqValSpills, SpillsToRm, SpillsToIns);
6
Calling 'HoistSpillHelper::runHoistSpills'
1559
1560 LLVM_DEBUG({do { } while (false)
1561 dbgs() << "Finally inserted spills in BB: ";do { } while (false)
1562 for (const auto &Ispill : SpillsToIns)do { } while (false)
1563 dbgs() << Ispill.first->getNumber() << " ";do { } while (false)
1564 dbgs() << "\nFinally removed spills in BB: ";do { } while (false)
1565 for (const auto Rspill : SpillsToRm)do { } while (false)
1566 dbgs() << Rspill->getParent()->getNumber() << " ";do { } while (false)
1567 dbgs() << "\n";do { } while (false)
1568 })do { } while (false);
1569
1570 // Stack live range update.
1571 LiveInterval &StackIntvl = LSS.getInterval(Slot);
1572 if (!SpillsToIns.empty() || !SpillsToRm.empty())
1573 StackIntvl.MergeValueInAsValue(OrigLI, OrigVNI,
1574 StackIntvl.getValNumInfo(0));
1575
1576 // Insert hoisted spills.
1577 for (auto const &Insert : SpillsToIns) {
1578 MachineBasicBlock *BB = Insert.first;
1579 Register LiveReg = Insert.second;
1580 MachineBasicBlock::iterator MII = IPA.getLastInsertPointIter(OrigLI, *BB);
1581 MachineInstrSpan MIS(MII, BB);
1582 TII.storeRegToStackSlot(*BB, MII, LiveReg, false, Slot,
1583 MRI.getRegClass(LiveReg), &TRI);
1584 LIS.InsertMachineInstrRangeInMaps(MIS.begin(), MII);
1585 for (const MachineInstr &MI : make_range(MIS.begin(), MII))
1586 getVDefInterval(MI, LIS);
1587 ++NumSpills;
1588 }
1589
1590 // Remove redundant spills or change them to dead instructions.
1591 NumSpills -= SpillsToRm.size();
1592 for (auto const RMEnt : SpillsToRm) {
1593 RMEnt->setDesc(TII.get(TargetOpcode::KILL));
1594 for (unsigned i = RMEnt->getNumOperands(); i; --i) {
1595 MachineOperand &MO = RMEnt->getOperand(i - 1);
1596 if (MO.isReg() && MO.isImplicit() && MO.isDef() && !MO.isDead())
1597 RMEnt->RemoveOperand(i - 1);
1598 }
1599 }
1600 Edit.eliminateDeadDefs(SpillsToRm, None, AA);
1601 }
1602}
1603
1604/// For VirtReg clone, the \p New register should have the same physreg or
1605/// stackslot as the \p old register.
1606void HoistSpillHelper::LRE_DidCloneVirtReg(Register New, Register Old) {
1607 if (VRM.hasPhys(Old))
1608 VRM.assignVirt2Phys(New, VRM.getPhys(Old));
1609 else if (VRM.getStackSlot(Old) != VirtRegMap::NO_STACK_SLOT)
1610 VRM.assignVirt2StackSlot(New, VRM.getStackSlot(Old));
1611 else
1612 llvm_unreachable("VReg should be assigned either physreg or stackslot")__builtin_unreachable();
1613 if (VRM.hasShape(Old))
1614 VRM.assignVirt2Shape(New, VRM.getShape(Old));
1615}

/usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/CodeGen/MachineDominators.h

1//==- llvm/CodeGen/MachineDominators.h - Machine Dom Calculation -*- C++ -*-==//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file defines classes mirroring those in llvm/Analysis/Dominators.h,
10// but for target-specific code rather than target-independent IR.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CODEGEN_MACHINEDOMINATORS_H
15#define LLVM_CODEGEN_MACHINEDOMINATORS_H
16
17#include "llvm/ADT/SmallSet.h"
18#include "llvm/ADT/SmallVector.h"
19#include "llvm/CodeGen/MachineBasicBlock.h"
20#include "llvm/CodeGen/MachineFunctionPass.h"
21#include "llvm/CodeGen/MachineInstr.h"
22#include "llvm/Support/GenericDomTree.h"
23#include "llvm/Support/GenericDomTreeConstruction.h"
24#include <cassert>
25#include <memory>
26
27namespace llvm {
28
29template <>
30inline void DominatorTreeBase<MachineBasicBlock, false>::addRoot(
31 MachineBasicBlock *MBB) {
32 this->Roots.push_back(MBB);
33}
34
35extern template class DomTreeNodeBase<MachineBasicBlock>;
36extern template class DominatorTreeBase<MachineBasicBlock, false>; // DomTree
37extern template class DominatorTreeBase<MachineBasicBlock, true>; // PostDomTree
38
39using MachineDomTreeNode = DomTreeNodeBase<MachineBasicBlock>;
40
41//===-------------------------------------
42/// DominatorTree Class - Concrete subclass of DominatorTreeBase that is used to
43/// compute a normal dominator tree.
44///
45class MachineDominatorTree : public MachineFunctionPass {
46 using DomTreeT = DomTreeBase<MachineBasicBlock>;
47
48 /// Helper structure used to hold all the basic blocks
49 /// involved in the split of a critical edge.
50 struct CriticalEdge {
51 MachineBasicBlock *FromBB;
52 MachineBasicBlock *ToBB;
53 MachineBasicBlock *NewBB;
54 };
55
56 /// Pile up all the critical edges to be split.
57 /// The splitting of a critical edge is local and thus, it is possible
58 /// to apply several of those changes at the same time.
59 mutable SmallVector<CriticalEdge, 32> CriticalEdgesToSplit;
60
61 /// Remember all the basic blocks that are inserted during
62 /// edge splitting.
63 /// Invariant: NewBBs == all the basic blocks contained in the NewBB
64 /// field of all the elements of CriticalEdgesToSplit.
65 /// I.e., forall elt in CriticalEdgesToSplit, it exists BB in NewBBs
66 /// such as BB == elt.NewBB.
67 mutable SmallSet<MachineBasicBlock *, 32> NewBBs;
68
69 /// The DominatorTreeBase that is used to compute a normal dominator tree.
70 std::unique_ptr<DomTreeT> DT;
71
72 /// Apply all the recorded critical edges to the DT.
73 /// This updates the underlying DT information in a way that uses
74 /// the fast query path of DT as much as possible.
75 ///
76 /// \post CriticalEdgesToSplit.empty().
77 void applySplitCriticalEdges() const;
78
79public:
80 static char ID; // Pass ID, replacement for typeid
81
82 MachineDominatorTree();
83 explicit MachineDominatorTree(MachineFunction &MF) : MachineFunctionPass(ID) {
84 calculate(MF);
85 }
86
87 DomTreeT &getBase() {
88 if (!DT) DT.reset(new DomTreeT());
89 applySplitCriticalEdges();
90 return *DT;
91 }
92
93 void getAnalysisUsage(AnalysisUsage &AU) const override;
94
95 MachineBasicBlock *getRoot() const {
96 applySplitCriticalEdges();
97 return DT->getRoot();
98 }
99
100 MachineDomTreeNode *getRootNode() const {
101 applySplitCriticalEdges();
102 return DT->getRootNode();
103 }
104
105 bool runOnMachineFunction(MachineFunction &F) override;
106
107 void calculate(MachineFunction &F);
108
109 bool dominates(const MachineDomTreeNode *A,
110 const MachineDomTreeNode *B) const {
111 applySplitCriticalEdges();
112 return DT->dominates(A, B);
113 }
114
115 bool dominates(const MachineBasicBlock *A, const MachineBasicBlock *B) const {
116 applySplitCriticalEdges();
117 return DT->dominates(A, B);
118 }
119
120 // dominates - Return true if A dominates B. This performs the
121 // special checks necessary if A and B are in the same basic block.
122 bool dominates(const MachineInstr *A, const MachineInstr *B) const {
123 applySplitCriticalEdges();
124 const MachineBasicBlock *BBA = A->getParent(), *BBB = B->getParent();
125 if (BBA != BBB) return DT->dominates(BBA, BBB);
126
127 // Loop through the basic block until we find A or B.
128 MachineBasicBlock::const_iterator I = BBA->begin();
129 for (; &*I != A && &*I != B; ++I)
130 /*empty*/ ;
131
132 return &*I == A;
133 }
134
135 bool properlyDominates(const MachineDomTreeNode *A,
136 const MachineDomTreeNode *B) const {
137 applySplitCriticalEdges();
138 return DT->properlyDominates(A, B);
139 }
140
141 bool properlyDominates(const MachineBasicBlock *A,
142 const MachineBasicBlock *B) const {
143 applySplitCriticalEdges();
144 return DT->properlyDominates(A, B);
145 }
146
147 /// findNearestCommonDominator - Find nearest common dominator basic block
148 /// for basic block A and B. If there is no such block then return NULL.
149 MachineBasicBlock *findNearestCommonDominator(MachineBasicBlock *A,
150 MachineBasicBlock *B) {
151 applySplitCriticalEdges();
152 return DT->findNearestCommonDominator(A, B);
153 }
154
155 MachineDomTreeNode *operator[](MachineBasicBlock *BB) const {
156 applySplitCriticalEdges();
157 return DT->getNode(BB);
9
Calling 'DominatorTreeBase::getNode'
19
Returning from 'DominatorTreeBase::getNode'
20
Returning pointer
158 }
159
160 /// getNode - return the (Post)DominatorTree node for the specified basic
161 /// block. This is the same as using operator[] on this class.
162 ///
163 MachineDomTreeNode *getNode(MachineBasicBlock *BB) const {
164 applySplitCriticalEdges();
165 return DT->getNode(BB);
166 }
167
168 /// addNewBlock - Add a new node to the dominator tree information. This
169 /// creates a new node as a child of DomBB dominator node,linking it into
170 /// the children list of the immediate dominator.
171 MachineDomTreeNode *addNewBlock(MachineBasicBlock *BB,
172 MachineBasicBlock *DomBB) {
173 applySplitCriticalEdges();
174 return DT->addNewBlock(BB, DomBB);
175 }
176
177 /// changeImmediateDominator - This method is used to update the dominator
178 /// tree information when a node's immediate dominator changes.
179 ///
180 void changeImmediateDominator(MachineBasicBlock *N,
181 MachineBasicBlock *NewIDom) {
182 applySplitCriticalEdges();
183 DT->changeImmediateDominator(N, NewIDom);
184 }
185
186 void changeImmediateDominator(MachineDomTreeNode *N,
187 MachineDomTreeNode *NewIDom) {
188 applySplitCriticalEdges();
189 DT->changeImmediateDominator(N, NewIDom);
190 }
191
192 /// eraseNode - Removes a node from the dominator tree. Block must not
193 /// dominate any other blocks. Removes node from its immediate dominator's
194 /// children list. Deletes dominator node associated with basic block BB.
195 void eraseNode(MachineBasicBlock *BB) {
196 applySplitCriticalEdges();
197 DT->eraseNode(BB);
198 }
199
200 /// splitBlock - BB is split and now it has one successor. Update dominator
201 /// tree to reflect this change.
202 void splitBlock(MachineBasicBlock* NewBB) {
203 applySplitCriticalEdges();
204 DT->splitBlock(NewBB);
205 }
206
207 /// isReachableFromEntry - Return true if A is dominated by the entry
208 /// block of the function containing it.
209 bool isReachableFromEntry(const MachineBasicBlock *A) {
210 applySplitCriticalEdges();
211 return DT->isReachableFromEntry(A);
212 }
213
214 void releaseMemory() override;
215
216 void verifyAnalysis() const override;
217
218 void print(raw_ostream &OS, const Module*) const override;
219
220 /// Record that the critical edge (FromBB, ToBB) has been
221 /// split with NewBB.
222 /// This is best to use this method instead of directly update the
223 /// underlying information, because this helps mitigating the
224 /// number of time the DT information is invalidated.
225 ///
226 /// \note Do not use this method with regular edges.
227 ///
228 /// \note To benefit from the compile time improvement incurred by this
229 /// method, the users of this method have to limit the queries to the DT
230 /// interface between two edges splitting. In other words, they have to
231 /// pack the splitting of critical edges as much as possible.
232 void recordSplitCriticalEdge(MachineBasicBlock *FromBB,
233 MachineBasicBlock *ToBB,
234 MachineBasicBlock *NewBB) {
235 bool Inserted = NewBBs.insert(NewBB).second;
236 (void)Inserted;
237 assert(Inserted &&((void)0)
238 "A basic block inserted via edge splitting cannot appear twice")((void)0);
239 CriticalEdgesToSplit.push_back({FromBB, ToBB, NewBB});
240 }
241};
242
243//===-------------------------------------
244/// DominatorTree GraphTraits specialization so the DominatorTree can be
245/// iterable by generic graph iterators.
246///
247
248template <class Node, class ChildIterator>
249struct MachineDomTreeGraphTraitsBase {
250 using NodeRef = Node *;
251 using ChildIteratorType = ChildIterator;
252
253 static NodeRef getEntryNode(NodeRef N) { return N; }
254 static ChildIteratorType child_begin(NodeRef N) { return N->begin(); }
255 static ChildIteratorType child_end(NodeRef N) { return N->end(); }
256};
257
258template <class T> struct GraphTraits;
259
260template <>
261struct GraphTraits<MachineDomTreeNode *>
262 : public MachineDomTreeGraphTraitsBase<MachineDomTreeNode,
263 MachineDomTreeNode::const_iterator> {
264};
265
266template <>
267struct GraphTraits<const MachineDomTreeNode *>
268 : public MachineDomTreeGraphTraitsBase<const MachineDomTreeNode,
269 MachineDomTreeNode::const_iterator> {
270};
271
272template <> struct GraphTraits<MachineDominatorTree*>
273 : public GraphTraits<MachineDomTreeNode *> {
274 static NodeRef getEntryNode(MachineDominatorTree *DT) {
275 return DT->getRootNode();
276 }
277};
278
279} // end namespace llvm
280
281#endif // LLVM_CODEGEN_MACHINEDOMINATORS_H

/usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Support/GenericDomTree.h

1//===- GenericDomTree.h - Generic dominator trees for graphs ----*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8/// \file
9///
10/// This file defines a set of templates that efficiently compute a dominator
11/// tree over a generic graph. This is used typically in LLVM for fast
12/// dominance queries on the CFG, but is fully generic w.r.t. the underlying
13/// graph types.
14///
15/// Unlike ADT/* graph algorithms, generic dominator tree has more requirements
16/// on the graph's NodeRef. The NodeRef should be a pointer and,
17/// NodeRef->getParent() must return the parent node that is also a pointer.
18///
19/// FIXME: Maybe GenericDomTree needs a TreeTraits, instead of GraphTraits.
20///
21//===----------------------------------------------------------------------===//
22
23#ifndef LLVM_SUPPORT_GENERICDOMTREE_H
24#define LLVM_SUPPORT_GENERICDOMTREE_H
25
26#include "llvm/ADT/DenseMap.h"
27#include "llvm/ADT/GraphTraits.h"
28#include "llvm/ADT/STLExtras.h"
29#include "llvm/ADT/SmallPtrSet.h"
30#include "llvm/ADT/SmallVector.h"
31#include "llvm/Support/CFGDiff.h"
32#include "llvm/Support/CFGUpdate.h"
33#include "llvm/Support/raw_ostream.h"
34#include <algorithm>
35#include <cassert>
36#include <cstddef>
37#include <iterator>
38#include <memory>
39#include <type_traits>
40#include <utility>
41
42namespace llvm {
43
44template <typename NodeT, bool IsPostDom>
45class DominatorTreeBase;
46
47namespace DomTreeBuilder {
48template <typename DomTreeT>
49struct SemiNCAInfo;
50} // namespace DomTreeBuilder
51
52/// Base class for the actual dominator tree node.
53template <class NodeT> class DomTreeNodeBase {
54 friend class PostDominatorTree;
55 friend class DominatorTreeBase<NodeT, false>;
56 friend class DominatorTreeBase<NodeT, true>;
57 friend struct DomTreeBuilder::SemiNCAInfo<DominatorTreeBase<NodeT, false>>;
58 friend struct DomTreeBuilder::SemiNCAInfo<DominatorTreeBase<NodeT, true>>;
59
60 NodeT *TheBB;
61 DomTreeNodeBase *IDom;
62 unsigned Level;
63 SmallVector<DomTreeNodeBase *, 4> Children;
64 mutable unsigned DFSNumIn = ~0;
65 mutable unsigned DFSNumOut = ~0;
66
67 public:
68 DomTreeNodeBase(NodeT *BB, DomTreeNodeBase *iDom)
69 : TheBB(BB), IDom(iDom), Level(IDom ? IDom->Level + 1 : 0) {}
70
71 using iterator = typename SmallVector<DomTreeNodeBase *, 4>::iterator;
72 using const_iterator =
73 typename SmallVector<DomTreeNodeBase *, 4>::const_iterator;
74
75 iterator begin() { return Children.begin(); }
76 iterator end() { return Children.end(); }
77 const_iterator begin() const { return Children.begin(); }
78 const_iterator end() const { return Children.end(); }
79
80 DomTreeNodeBase *const &back() const { return Children.back(); }
81 DomTreeNodeBase *&back() { return Children.back(); }
82
83 iterator_range<iterator> children() { return make_range(begin(), end()); }
84 iterator_range<const_iterator> children() const {
85 return make_range(begin(), end());
86 }
87
88 NodeT *getBlock() const { return TheBB; }
89 DomTreeNodeBase *getIDom() const { return IDom; }
90 unsigned getLevel() const { return Level; }
91
92 std::unique_ptr<DomTreeNodeBase> addChild(
93 std::unique_ptr<DomTreeNodeBase> C) {
94 Children.push_back(C.get());
95 return C;
96 }
97
98 bool isLeaf() const { return Children.empty(); }
99 size_t getNumChildren() const { return Children.size(); }
100
101 void clearAllChildren() { Children.clear(); }
102
103 bool compare(const DomTreeNodeBase *Other) const {
104 if (getNumChildren() != Other->getNumChildren())
105 return true;
106
107 if (Level != Other->Level) return true;
108
109 SmallPtrSet<const NodeT *, 4> OtherChildren;
110 for (const DomTreeNodeBase *I : *Other) {
111 const NodeT *Nd = I->getBlock();
112 OtherChildren.insert(Nd);
113 }
114
115 for (const DomTreeNodeBase *I : *this) {
116 const NodeT *N = I->getBlock();
117 if (OtherChildren.count(N) == 0)
118 return true;
119 }
120 return false;
121 }
122
123 void setIDom(DomTreeNodeBase *NewIDom) {
124 assert(IDom && "No immediate dominator?")((void)0);
125 if (IDom == NewIDom) return;
126
127 auto I = find(IDom->Children, this);
128 assert(I != IDom->Children.end() &&((void)0)
129 "Not in immediate dominator children set!")((void)0);
130 // I am no longer your child...
131 IDom->Children.erase(I);
132
133 // Switch to new dominator
134 IDom = NewIDom;
135 IDom->Children.push_back(this);
136
137 UpdateLevel();
138 }
139
140 /// getDFSNumIn/getDFSNumOut - These return the DFS visitation order for nodes
141 /// in the dominator tree. They are only guaranteed valid if
142 /// updateDFSNumbers() has been called.
143 unsigned getDFSNumIn() const { return DFSNumIn; }
144 unsigned getDFSNumOut() const { return DFSNumOut; }
145
146private:
147 // Return true if this node is dominated by other. Use this only if DFS info
148 // is valid.
149 bool DominatedBy(const DomTreeNodeBase *other) const {
150 return this->DFSNumIn >= other->DFSNumIn &&
151 this->DFSNumOut <= other->DFSNumOut;
152 }
153
154 void UpdateLevel() {
155 assert(IDom)((void)0);
156 if (Level == IDom->Level + 1) return;
157
158 SmallVector<DomTreeNodeBase *, 64> WorkStack = {this};
159
160 while (!WorkStack.empty()) {
161 DomTreeNodeBase *Current = WorkStack.pop_back_val();
162 Current->Level = Current->IDom->Level + 1;
163
164 for (DomTreeNodeBase *C : *Current) {
165 assert(C->IDom)((void)0);
166 if (C->Level != C->IDom->Level + 1) WorkStack.push_back(C);
167 }
168 }
169 }
170};
171
172template <class NodeT>
173raw_ostream &operator<<(raw_ostream &O, const DomTreeNodeBase<NodeT> *Node) {
174 if (Node->getBlock())
175 Node->getBlock()->printAsOperand(O, false);
176 else
177 O << " <<exit node>>";
178
179 O << " {" << Node->getDFSNumIn() << "," << Node->getDFSNumOut() << "} ["
180 << Node->getLevel() << "]\n";
181
182 return O;
183}
184
185template <class NodeT>
186void PrintDomTree(const DomTreeNodeBase<NodeT> *N, raw_ostream &O,
187 unsigned Lev) {
188 O.indent(2 * Lev) << "[" << Lev << "] " << N;
189 for (typename DomTreeNodeBase<NodeT>::const_iterator I = N->begin(),
190 E = N->end();
191 I != E; ++I)
192 PrintDomTree<NodeT>(*I, O, Lev + 1);
193}
194
195namespace DomTreeBuilder {
196// The routines below are provided in a separate header but referenced here.
197template <typename DomTreeT>
198void Calculate(DomTreeT &DT);
199
200template <typename DomTreeT>
201void CalculateWithUpdates(DomTreeT &DT,
202 ArrayRef<typename DomTreeT::UpdateType> Updates);
203
204template <typename DomTreeT>
205void InsertEdge(DomTreeT &DT, typename DomTreeT::NodePtr From,
206 typename DomTreeT::NodePtr To);
207
208template <typename DomTreeT>
209void DeleteEdge(DomTreeT &DT, typename DomTreeT::NodePtr From,
210 typename DomTreeT::NodePtr To);
211
212template <typename DomTreeT>
213void ApplyUpdates(DomTreeT &DT,
214 GraphDiff<typename DomTreeT::NodePtr,
215 DomTreeT::IsPostDominator> &PreViewCFG,
216 GraphDiff<typename DomTreeT::NodePtr,
217 DomTreeT::IsPostDominator> *PostViewCFG);
218
219template <typename DomTreeT>
220bool Verify(const DomTreeT &DT, typename DomTreeT::VerificationLevel VL);
221} // namespace DomTreeBuilder
222
223/// Core dominator tree base class.
224///
225/// This class is a generic template over graph nodes. It is instantiated for
226/// various graphs in the LLVM IR or in the code generator.
227template <typename NodeT, bool IsPostDom>
228class DominatorTreeBase {
229 public:
230 static_assert(std::is_pointer<typename GraphTraits<NodeT *>::NodeRef>::value,
231 "Currently DominatorTreeBase supports only pointer nodes");
232 using NodeType = NodeT;
233 using NodePtr = NodeT *;
234 using ParentPtr = decltype(std::declval<NodeT *>()->getParent());
235 static_assert(std::is_pointer<ParentPtr>::value,
236 "Currently NodeT's parent must be a pointer type");
237 using ParentType = std::remove_pointer_t<ParentPtr>;
238 static constexpr bool IsPostDominator = IsPostDom;
239
240 using UpdateType = cfg::Update<NodePtr>;
241 using UpdateKind = cfg::UpdateKind;
242 static constexpr UpdateKind Insert = UpdateKind::Insert;
243 static constexpr UpdateKind Delete = UpdateKind::Delete;
244
245 enum class VerificationLevel { Fast, Basic, Full };
246
247protected:
248 // Dominators always have a single root, postdominators can have more.
249 SmallVector<NodeT *, IsPostDom ? 4 : 1> Roots;
250
251 using DomTreeNodeMapType =
252 DenseMap<NodeT *, std::unique_ptr<DomTreeNodeBase<NodeT>>>;
253 DomTreeNodeMapType DomTreeNodes;
254 DomTreeNodeBase<NodeT> *RootNode = nullptr;
255 ParentPtr Parent = nullptr;
256
257 mutable bool DFSInfoValid = false;
258 mutable unsigned int SlowQueries = 0;
259
260 friend struct DomTreeBuilder::SemiNCAInfo<DominatorTreeBase>;
261
262 public:
263 DominatorTreeBase() {}
264
265 DominatorTreeBase(DominatorTreeBase &&Arg)
266 : Roots(std::move(Arg.Roots)),
267 DomTreeNodes(std::move(Arg.DomTreeNodes)),
268 RootNode(Arg.RootNode),
269 Parent(Arg.Parent),
270 DFSInfoValid(Arg.DFSInfoValid),
271 SlowQueries(Arg.SlowQueries) {
272 Arg.wipe();
273 }
274
275 DominatorTreeBase &operator=(DominatorTreeBase &&RHS) {
276 Roots = std::move(RHS.Roots);
277 DomTreeNodes = std::move(RHS.DomTreeNodes);
278 RootNode = RHS.RootNode;
279 Parent = RHS.Parent;
280 DFSInfoValid = RHS.DFSInfoValid;
281 SlowQueries = RHS.SlowQueries;
282 RHS.wipe();
283 return *this;
284 }
285
286 DominatorTreeBase(const DominatorTreeBase &) = delete;
287 DominatorTreeBase &operator=(const DominatorTreeBase &) = delete;
288
289 /// Iteration over roots.
290 ///
291 /// This may include multiple blocks if we are computing post dominators.
292 /// For forward dominators, this will always be a single block (the entry
293 /// block).
294 using root_iterator = typename SmallVectorImpl<NodeT *>::iterator;
295 using const_root_iterator = typename SmallVectorImpl<NodeT *>::const_iterator;
296
297 root_iterator root_begin() { return Roots.begin(); }
298 const_root_iterator root_begin() const { return Roots.begin(); }
299 root_iterator root_end() { return Roots.end(); }
300 const_root_iterator root_end() const { return Roots.end(); }
301
302 size_t root_size() const { return Roots.size(); }
303
304 iterator_range<root_iterator> roots() {
305 return make_range(root_begin(), root_end());
306 }
307 iterator_range<const_root_iterator> roots() const {
308 return make_range(root_begin(), root_end());
309 }
310
311 /// isPostDominator - Returns true if analysis based of postdoms
312 ///
313 bool isPostDominator() const { return IsPostDominator; }
314
315 /// compare - Return false if the other dominator tree base matches this
316 /// dominator tree base. Otherwise return true.
317 bool compare(const DominatorTreeBase &Other) const {
318 if (Parent != Other.Parent) return true;
319
320 if (Roots.size() != Other.Roots.size())
321 return true;
322
323 if (!std::is_permutation(Roots.begin(), Roots.end(), Other.Roots.begin()))
324 return true;
325
326 const DomTreeNodeMapType &OtherDomTreeNodes = Other.DomTreeNodes;
327 if (DomTreeNodes.size() != OtherDomTreeNodes.size())
328 return true;
329
330 for (const auto &DomTreeNode : DomTreeNodes) {
331 NodeT *BB = DomTreeNode.first;
332 typename DomTreeNodeMapType::const_iterator OI =
333 OtherDomTreeNodes.find(BB);
334 if (OI == OtherDomTreeNodes.end())
335 return true;
336
337 DomTreeNodeBase<NodeT> &MyNd = *DomTreeNode.second;
338 DomTreeNodeBase<NodeT> &OtherNd = *OI->second;
339
340 if (MyNd.compare(&OtherNd))
341 return true;
342 }
343
344 return false;
345 }
346
347 /// getNode - return the (Post)DominatorTree node for the specified basic
348 /// block. This is the same as using operator[] on this class. The result
349 /// may (but is not required to) be null for a forward (backwards)
350 /// statically unreachable block.
351 DomTreeNodeBase<NodeT> *getNode(const NodeT *BB) const {
352 auto I = DomTreeNodes.find(BB);
353 if (I != DomTreeNodes.end())
10
Calling 'operator!='
16
Returning from 'operator!='
17
Taking true branch
354 return I->second.get();
18
Returning pointer
355 return nullptr;
356 }
357
358 /// See getNode.
359 DomTreeNodeBase<NodeT> *operator[](const NodeT *BB) const {
360 return getNode(BB);
361 }
362
363 /// getRootNode - This returns the entry node for the CFG of the function. If
364 /// this tree represents the post-dominance relations for a function, however,
365 /// this root may be a node with the block == NULL. This is the case when
366 /// there are multiple exit nodes from a particular function. Consumers of
367 /// post-dominance information must be capable of dealing with this
368 /// possibility.
369 ///
370 DomTreeNodeBase<NodeT> *getRootNode() { return RootNode; }
371 const DomTreeNodeBase<NodeT> *getRootNode() const { return RootNode; }
372
373 /// Get all nodes dominated by R, including R itself.
374 void getDescendants(NodeT *R, SmallVectorImpl<NodeT *> &Result) const {
375 Result.clear();
376 const DomTreeNodeBase<NodeT> *RN = getNode(R);
377 if (!RN)
378 return; // If R is unreachable, it will not be present in the DOM tree.
379 SmallVector<const DomTreeNodeBase<NodeT> *, 8> WL;
380 WL.push_back(RN);
381
382 while (!WL.empty()) {
383 const DomTreeNodeBase<NodeT> *N = WL.pop_back_val();
384 Result.push_back(N->getBlock());
385 WL.append(N->begin(), N->end());
386 }
387 }
388
389 /// properlyDominates - Returns true iff A dominates B and A != B.
390 /// Note that this is not a constant time operation!
391 ///
392 bool properlyDominates(const DomTreeNodeBase<NodeT> *A,
393 const DomTreeNodeBase<NodeT> *B) const {
394 if (!A || !B)
395 return false;
396 if (A == B)
397 return false;
398 return dominates(A, B);
399 }
400
401 bool properlyDominates(const NodeT *A, const NodeT *B) const;
402
403 /// isReachableFromEntry - Return true if A is dominated by the entry
404 /// block of the function containing it.
405 bool isReachableFromEntry(const NodeT *A) const {
406 assert(!this->isPostDominator() &&((void)0)
407 "This is not implemented for post dominators")((void)0);
408 return isReachableFromEntry(getNode(const_cast<NodeT *>(A)));
409 }
410
411 bool isReachableFromEntry(const DomTreeNodeBase<NodeT> *A) const { return A; }
412
413 /// dominates - Returns true iff A dominates B. Note that this is not a
414 /// constant time operation!
415 ///
416 bool dominates(const DomTreeNodeBase<NodeT> *A,
417 const DomTreeNodeBase<NodeT> *B) const {
418 // A node trivially dominates itself.
419 if (B == A)
420 return true;
421
422 // An unreachable node is dominated by anything.
423 if (!isReachableFromEntry(B))
424 return true;
425
426 // And dominates nothing.
427 if (!isReachableFromEntry(A))
428 return false;
429
430 if (B->getIDom() == A) return true;
431
432 if (A->getIDom() == B) return false;
433
434 // A can only dominate B if it is higher in the tree.
435 if (A->getLevel() >= B->getLevel()) return false;
436
437 // Compare the result of the tree walk and the dfs numbers, if expensive
438 // checks are enabled.
439#ifdef EXPENSIVE_CHECKS
440 assert((!DFSInfoValid ||((void)0)
441 (dominatedBySlowTreeWalk(A, B) == B->DominatedBy(A))) &&((void)0)
442 "Tree walk disagrees with dfs numbers!")((void)0);
443#endif
444
445 if (DFSInfoValid)
446 return B->DominatedBy(A);
447
448 // If we end up with too many slow queries, just update the
449 // DFS numbers on the theory that we are going to keep querying.
450 SlowQueries++;
451 if (SlowQueries > 32) {
452 updateDFSNumbers();
453 return B->DominatedBy(A);
454 }
455
456 return dominatedBySlowTreeWalk(A, B);
457 }
458
459 bool dominates(const NodeT *A, const NodeT *B) const;
460
461 NodeT *getRoot() const {
462 assert(this->Roots.size() == 1 && "Should always have entry node!")((void)0);
463 return this->Roots[0];
464 }
465
466 /// Find nearest common dominator basic block for basic block A and B. A and B
467 /// must have tree nodes.
468 NodeT *findNearestCommonDominator(NodeT *A, NodeT *B) const {
469 assert(A && B && "Pointers are not valid")((void)0);
470 assert(A->getParent() == B->getParent() &&((void)0)
471 "Two blocks are not in same function")((void)0);
472
473 // If either A or B is a entry block then it is nearest common dominator
474 // (for forward-dominators).
475 if (!isPostDominator()) {
476 NodeT &Entry = A->getParent()->front();
477 if (A == &Entry || B == &Entry)
478 return &Entry;
479 }
480
481 DomTreeNodeBase<NodeT> *NodeA = getNode(A);
482 DomTreeNodeBase<NodeT> *NodeB = getNode(B);
483 assert(NodeA && "A must be in the tree")((void)0);
484 assert(NodeB && "B must be in the tree")((void)0);
485
486 // Use level information to go up the tree until the levels match. Then
487 // continue going up til we arrive at the same node.
488 while (NodeA != NodeB) {
489 if (NodeA->getLevel() < NodeB->getLevel()) std::swap(NodeA, NodeB);
490
491 NodeA = NodeA->IDom;
492 }
493
494 return NodeA->getBlock();
495 }
496
497 const NodeT *findNearestCommonDominator(const NodeT *A,
498 const NodeT *B) const {
499 // Cast away the const qualifiers here. This is ok since
500 // const is re-introduced on the return type.
501 return findNearestCommonDominator(const_cast<NodeT *>(A),
502 const_cast<NodeT *>(B));
503 }
504
505 bool isVirtualRoot(const DomTreeNodeBase<NodeT> *A) const {
506 return isPostDominator() && !A->getBlock();
507 }
508
509 //===--------------------------------------------------------------------===//
510 // API to update (Post)DominatorTree information based on modifications to
511 // the CFG...
512
513 /// Inform the dominator tree about a sequence of CFG edge insertions and
514 /// deletions and perform a batch update on the tree.
515 ///
516 /// This function should be used when there were multiple CFG updates after
517 /// the last dominator tree update. It takes care of performing the updates
518 /// in sync with the CFG and optimizes away the redundant operations that
519 /// cancel each other.
520 /// The functions expects the sequence of updates to be balanced. Eg.:
521 /// - {{Insert, A, B}, {Delete, A, B}, {Insert, A, B}} is fine, because
522 /// logically it results in a single insertions.
523 /// - {{Insert, A, B}, {Insert, A, B}} is invalid, because it doesn't make
524 /// sense to insert the same edge twice.
525 ///
526 /// What's more, the functions assumes that it's safe to ask every node in the
527 /// CFG about its children and inverse children. This implies that deletions
528 /// of CFG edges must not delete the CFG nodes before calling this function.
529 ///
530 /// The applyUpdates function can reorder the updates and remove redundant
531 /// ones internally. The batch updater is also able to detect sequences of
532 /// zero and exactly one update -- it's optimized to do less work in these
533 /// cases.
534 ///
535 /// Note that for postdominators it automatically takes care of applying
536 /// updates on reverse edges internally (so there's no need to swap the
537 /// From and To pointers when constructing DominatorTree::UpdateType).
538 /// The type of updates is the same for DomTreeBase<T> and PostDomTreeBase<T>
539 /// with the same template parameter T.
540 ///
541 /// \param Updates An unordered sequence of updates to perform. The current
542 /// CFG and the reverse of these updates provides the pre-view of the CFG.
543 ///
544 void applyUpdates(ArrayRef<UpdateType> Updates) {
545 GraphDiff<NodePtr, IsPostDominator> PreViewCFG(
546 Updates, /*ReverseApplyUpdates=*/true);
547 DomTreeBuilder::ApplyUpdates(*this, PreViewCFG, nullptr);
548 }
549
550 /// \param Updates An unordered sequence of updates to perform. The current
551 /// CFG and the reverse of these updates provides the pre-view of the CFG.
552 /// \param PostViewUpdates An unordered sequence of update to perform in order
553 /// to obtain a post-view of the CFG. The DT will be updated assuming the
554 /// obtained PostViewCFG is the desired end state.
555 void applyUpdates(ArrayRef<UpdateType> Updates,
556 ArrayRef<UpdateType> PostViewUpdates) {
557 if (Updates.empty()) {
558 GraphDiff<NodePtr, IsPostDom> PostViewCFG(PostViewUpdates);
559 DomTreeBuilder::ApplyUpdates(*this, PostViewCFG, &PostViewCFG);
560 } else {
561 // PreViewCFG needs to merge Updates and PostViewCFG. The updates in
562 // Updates need to be reversed, and match the direction in PostViewCFG.
563 // The PostViewCFG is created with updates reversed (equivalent to changes
564 // made to the CFG), so the PreViewCFG needs all the updates reverse
565 // applied.
566 SmallVector<UpdateType> AllUpdates(Updates.begin(), Updates.end());
567 append_range(AllUpdates, PostViewUpdates);
568 GraphDiff<NodePtr, IsPostDom> PreViewCFG(AllUpdates,
569 /*ReverseApplyUpdates=*/true);
570 GraphDiff<NodePtr, IsPostDom> PostViewCFG(PostViewUpdates);
571 DomTreeBuilder::ApplyUpdates(*this, PreViewCFG, &PostViewCFG);
572 }
573 }
574
575 /// Inform the dominator tree about a CFG edge insertion and update the tree.
576 ///
577 /// This function has to be called just before or just after making the update
578 /// on the actual CFG. There cannot be any other updates that the dominator
579 /// tree doesn't know about.
580 ///
581 /// Note that for postdominators it automatically takes care of inserting
582 /// a reverse edge internally (so there's no need to swap the parameters).
583 ///
584 void insertEdge(NodeT *From, NodeT *To) {
585 assert(From)((void)0);
586 assert(To)((void)0);
587 assert(From->getParent() == Parent)((void)0);
588 assert(To->getParent() == Parent)((void)0);
589 DomTreeBuilder::InsertEdge(*this, From, To);
590 }
591
592 /// Inform the dominator tree about a CFG edge deletion and update the tree.
593 ///
594 /// This function has to be called just after making the update on the actual
595 /// CFG. An internal functions checks if the edge doesn't exist in the CFG in
596 /// DEBUG mode. There cannot be any other updates that the
597 /// dominator tree doesn't know about.
598 ///
599 /// Note that for postdominators it automatically takes care of deleting
600 /// a reverse edge internally (so there's no need to swap the parameters).
601 ///
602 void deleteEdge(NodeT *From, NodeT *To) {
603 assert(From)((void)0);
604 assert(To)((void)0);
605 assert(From->getParent() == Parent)((void)0);
606 assert(To->getParent() == Parent)((void)0);
607 DomTreeBuilder::DeleteEdge(*this, From, To);
608 }
609
610 /// Add a new node to the dominator tree information.
611 ///
612 /// This creates a new node as a child of DomBB dominator node, linking it
613 /// into the children list of the immediate dominator.
614 ///
615 /// \param BB New node in CFG.
616 /// \param DomBB CFG node that is dominator for BB.
617 /// \returns New dominator tree node that represents new CFG node.
618 ///
619 DomTreeNodeBase<NodeT> *addNewBlock(NodeT *BB, NodeT *DomBB) {
620 assert(getNode(BB) == nullptr && "Block already in dominator tree!")((void)0);
621 DomTreeNodeBase<NodeT> *IDomNode = getNode(DomBB);
622 assert(IDomNode && "Not immediate dominator specified for block!")((void)0);
623 DFSInfoValid = false;
624 return createChild(BB, IDomNode);
625 }
626
627 /// Add a new node to the forward dominator tree and make it a new root.
628 ///
629 /// \param BB New node in CFG.
630 /// \returns New dominator tree node that represents new CFG node.
631 ///
632 DomTreeNodeBase<NodeT> *setNewRoot(NodeT *BB) {
633 assert(getNode(BB) == nullptr && "Block already in dominator tree!")((void)0);
634 assert(!this->isPostDominator() &&((void)0)
635 "Cannot change root of post-dominator tree")((void)0);
636 DFSInfoValid = false;
637 DomTreeNodeBase<NodeT> *NewNode = createNode(BB);
638 if (Roots.empty()) {
639 addRoot(BB);
640 } else {
641 assert(Roots.size() == 1)((void)0);
642 NodeT *OldRoot = Roots.front();
643 auto &OldNode = DomTreeNodes[OldRoot];
644 OldNode = NewNode->addChild(std::move(DomTreeNodes[OldRoot]));
645 OldNode->IDom = NewNode;
646 OldNode->UpdateLevel();
647 Roots[0] = BB;
648 }
649 return RootNode = NewNode;
650 }
651
652 /// changeImmediateDominator - This method is used to update the dominator
653 /// tree information when a node's immediate dominator changes.
654 ///
655 void changeImmediateDominator(DomTreeNodeBase<NodeT> *N,
656 DomTreeNodeBase<NodeT> *NewIDom) {
657 assert(N && NewIDom && "Cannot change null node pointers!")((void)0);
658 DFSInfoValid = false;
659 N->setIDom(NewIDom);
660 }
661
662 void changeImmediateDominator(NodeT *BB, NodeT *NewBB) {
663 changeImmediateDominator(getNode(BB), getNode(NewBB));
664 }
665
666 /// eraseNode - Removes a node from the dominator tree. Block must not
667 /// dominate any other blocks. Removes node from its immediate dominator's
668 /// children list. Deletes dominator node associated with basic block BB.
669 void eraseNode(NodeT *BB) {
670 DomTreeNodeBase<NodeT> *Node = getNode(BB);
671 assert(Node && "Removing node that isn't in dominator tree.")((void)0);
672 assert(Node->isLeaf() && "Node is not a leaf node.")((void)0);
673
674 DFSInfoValid = false;
675
676 // Remove node from immediate dominator's children list.
677 DomTreeNodeBase<NodeT> *IDom = Node->getIDom();
678 if (IDom) {
679 const auto I = find(IDom->Children, Node);
680 assert(I != IDom->Children.end() &&((void)0)
681 "Not in immediate dominator children set!")((void)0);
682 // I am no longer your child...
683 IDom->Children.erase(I);
684 }
685
686 DomTreeNodes.erase(BB);
687
688 if (!IsPostDom) return;
689
690 // Remember to update PostDominatorTree roots.
691 auto RIt = llvm::find(Roots, BB);
692 if (RIt != Roots.end()) {
693 std::swap(*RIt, Roots.back());
694 Roots.pop_back();
695 }
696 }
697
698 /// splitBlock - BB is split and now it has one successor. Update dominator
699 /// tree to reflect this change.
700 void splitBlock(NodeT *NewBB) {
701 if (IsPostDominator)
702 Split<Inverse<NodeT *>>(NewBB);
703 else
704 Split<NodeT *>(NewBB);
705 }
706
707 /// print - Convert to human readable form
708 ///
709 void print(raw_ostream &O) const {
710 O << "=============================--------------------------------\n";
711 if (IsPostDominator)
712 O << "Inorder PostDominator Tree: ";
713 else
714 O << "Inorder Dominator Tree: ";
715 if (!DFSInfoValid)
716 O << "DFSNumbers invalid: " << SlowQueries << " slow queries.";
717 O << "\n";
718
719 // The postdom tree can have a null root if there are no returns.
720 if (getRootNode()) PrintDomTree<NodeT>(getRootNode(), O, 1);
721 O << "Roots: ";
722 for (const NodePtr Block : Roots) {
723 Block->printAsOperand(O, false);
724 O << " ";
725 }
726 O << "\n";
727 }
728
729public:
730 /// updateDFSNumbers - Assign In and Out numbers to the nodes while walking
731 /// dominator tree in dfs order.
732 void updateDFSNumbers() const {
733 if (DFSInfoValid) {
734 SlowQueries = 0;
735 return;
736 }
737
738 SmallVector<std::pair<const DomTreeNodeBase<NodeT> *,
739 typename DomTreeNodeBase<NodeT>::const_iterator>,
740 32> WorkStack;
741
742 const DomTreeNodeBase<NodeT> *ThisRoot = getRootNode();
743 assert((!Parent || ThisRoot) && "Empty constructed DomTree")((void)0);
744 if (!ThisRoot)
745 return;
746
747 // Both dominators and postdominators have a single root node. In the case
748 // case of PostDominatorTree, this node is a virtual root.
749 WorkStack.push_back({ThisRoot, ThisRoot->begin()});
750
751 unsigned DFSNum = 0;
752 ThisRoot->DFSNumIn = DFSNum++;
753
754 while (!WorkStack.empty()) {
755 const DomTreeNodeBase<NodeT> *Node = WorkStack.back().first;
756 const auto ChildIt = WorkStack.back().second;
757
758 // If we visited all of the children of this node, "recurse" back up the
759 // stack setting the DFOutNum.
760 if (ChildIt == Node->end()) {
761 Node->DFSNumOut = DFSNum++;
762 WorkStack.pop_back();
763 } else {
764 // Otherwise, recursively visit this child.
765 const DomTreeNodeBase<NodeT> *Child = *ChildIt;
766 ++WorkStack.back().second;
767
768 WorkStack.push_back({Child, Child->begin()});
769 Child->DFSNumIn = DFSNum++;
770 }
771 }
772
773 SlowQueries = 0;
774 DFSInfoValid = true;
775 }
776
777 /// recalculate - compute a dominator tree for the given function
778 void recalculate(ParentType &Func) {
779 Parent = &Func;
780 DomTreeBuilder::Calculate(*this);
781 }
782
783 void recalculate(ParentType &Func, ArrayRef<UpdateType> Updates) {
784 Parent = &Func;
785 DomTreeBuilder::CalculateWithUpdates(*this, Updates);
786 }
787
788 /// verify - checks if the tree is correct. There are 3 level of verification:
789 /// - Full -- verifies if the tree is correct by making sure all the
790 /// properties (including the parent and the sibling property)
791 /// hold.
792 /// Takes O(N^3) time.
793 ///
794 /// - Basic -- checks if the tree is correct, but compares it to a freshly
795 /// constructed tree instead of checking the sibling property.
796 /// Takes O(N^2) time.
797 ///
798 /// - Fast -- checks basic tree structure and compares it with a freshly
799 /// constructed tree.
800 /// Takes O(N^2) time worst case, but is faster in practise (same
801 /// as tree construction).
802 bool verify(VerificationLevel VL = VerificationLevel::Full) const {
803 return DomTreeBuilder::Verify(*this, VL);
804 }
805
806 void reset() {
807 DomTreeNodes.clear();
808 Roots.clear();
809 RootNode = nullptr;
810 Parent = nullptr;
811 DFSInfoValid = false;
812 SlowQueries = 0;
813 }
814
815protected:
816 void addRoot(NodeT *BB) { this->Roots.push_back(BB); }
817
818 DomTreeNodeBase<NodeT> *createChild(NodeT *BB, DomTreeNodeBase<NodeT> *IDom) {
819 return (DomTreeNodes[BB] = IDom->addChild(
820 std::make_unique<DomTreeNodeBase<NodeT>>(BB, IDom)))
821 .get();
822 }
823
824 DomTreeNodeBase<NodeT> *createNode(NodeT *BB) {
825 return (DomTreeNodes[BB] =
826 std::make_unique<DomTreeNodeBase<NodeT>>(BB, nullptr))
827 .get();
828 }
829
830 // NewBB is split and now it has one successor. Update dominator tree to
831 // reflect this change.
832 template <class N>
833 void Split(typename GraphTraits<N>::NodeRef NewBB) {
834 using GraphT = GraphTraits<N>;
835 using NodeRef = typename GraphT::NodeRef;
836 assert(std::distance(GraphT::child_begin(NewBB),((void)0)
837 GraphT::child_end(NewBB)) == 1 &&((void)0)
838 "NewBB should have a single successor!")((void)0);
839 NodeRef NewBBSucc = *GraphT::child_begin(NewBB);
840
841 SmallVector<NodeRef, 4> PredBlocks(children<Inverse<N>>(NewBB));
842
843 assert(!PredBlocks.empty() && "No predblocks?")((void)0);
844
845 bool NewBBDominatesNewBBSucc = true;
846 for (auto Pred : children<Inverse<N>>(NewBBSucc)) {
847 if (Pred != NewBB && !dominates(NewBBSucc, Pred) &&
848 isReachableFromEntry(Pred)) {
849 NewBBDominatesNewBBSucc = false;
850 break;
851 }
852 }
853
854 // Find NewBB's immediate dominator and create new dominator tree node for
855 // NewBB.
856 NodeT *NewBBIDom = nullptr;
857 unsigned i = 0;
858 for (i = 0; i < PredBlocks.size(); ++i)
859 if (isReachableFromEntry(PredBlocks[i])) {
860 NewBBIDom = PredBlocks[i];
861 break;
862 }
863
864 // It's possible that none of the predecessors of NewBB are reachable;
865 // in that case, NewBB itself is unreachable, so nothing needs to be
866 // changed.
867 if (!NewBBIDom) return;
868
869 for (i = i + 1; i < PredBlocks.size(); ++i) {
870 if (isReachableFromEntry(PredBlocks[i]))
871 NewBBIDom = findNearestCommonDominator(NewBBIDom, PredBlocks[i]);
872 }
873
874 // Create the new dominator tree node... and set the idom of NewBB.
875 DomTreeNodeBase<NodeT> *NewBBNode = addNewBlock(NewBB, NewBBIDom);
876
877 // If NewBB strictly dominates other blocks, then it is now the immediate
878 // dominator of NewBBSucc. Update the dominator tree as appropriate.
879 if (NewBBDominatesNewBBSucc) {
880 DomTreeNodeBase<NodeT> *NewBBSuccNode = getNode(NewBBSucc);
881 changeImmediateDominator(NewBBSuccNode, NewBBNode);
882 }
883 }
884
885 private:
886 bool dominatedBySlowTreeWalk(const DomTreeNodeBase<NodeT> *A,
887 const DomTreeNodeBase<NodeT> *B) const {
888 assert(A != B)((void)0);
889 assert(isReachableFromEntry(B))((void)0);
890 assert(isReachableFromEntry(A))((void)0);
891
892 const unsigned ALevel = A->getLevel();
893 const DomTreeNodeBase<NodeT> *IDom;
894
895 // Don't walk nodes above A's subtree. When we reach A's level, we must
896 // either find A or be in some other subtree not dominated by A.
897 while ((IDom = B->getIDom()) != nullptr && IDom->getLevel() >= ALevel)
898 B = IDom; // Walk up the tree
899
900 return B == A;
901 }
902
903 /// Wipe this tree's state without releasing any resources.
904 ///
905 /// This is essentially a post-move helper only. It leaves the object in an
906 /// assignable and destroyable state, but otherwise invalid.
907 void wipe() {
908 DomTreeNodes.clear();
909 RootNode = nullptr;
910 Parent = nullptr;
911 }
912};
913
914template <typename T>
915using DomTreeBase = DominatorTreeBase<T, false>;
916
917template <typename T>
918using PostDomTreeBase = DominatorTreeBase<T, true>;
919
920// These two functions are declared out of line as a workaround for building
921// with old (< r147295) versions of clang because of pr11642.
922template <typename NodeT, bool IsPostDom>
923bool DominatorTreeBase<NodeT, IsPostDom>::dominates(const NodeT *A,
924 const NodeT *B) const {
925 if (A == B)
926 return true;
927
928 // Cast away the const qualifiers here. This is ok since
929 // this function doesn't actually return the values returned
930 // from getNode.
931 return dominates(getNode(const_cast<NodeT *>(A)),
932 getNode(const_cast<NodeT *>(B)));
933}
934template <typename NodeT, bool IsPostDom>
935bool DominatorTreeBase<NodeT, IsPostDom>::properlyDominates(
936 const NodeT *A, const NodeT *B) const {
937 if (A == B)
938 return false;
939
940 // Cast away the const qualifiers here. This is ok since
941 // this function doesn't actually return the values returned
942 // from getNode.
943 return dominates(getNode(const_cast<NodeT *>(A)),
944 getNode(const_cast<NodeT *>(B)));
945}
946
947} // end namespace llvm
948
949#endif // LLVM_SUPPORT_GENERICDOMTREE_H

/usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/ADT/DenseMap.h

1//===- llvm/ADT/DenseMap.h - Dense probed hash table ------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file defines the DenseMap class.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_ADT_DENSEMAP_H
14#define LLVM_ADT_DENSEMAP_H
15
16#include "llvm/ADT/DenseMapInfo.h"
17#include "llvm/ADT/EpochTracker.h"
18#include "llvm/Support/AlignOf.h"
19#include "llvm/Support/Compiler.h"
20#include "llvm/Support/MathExtras.h"
21#include "llvm/Support/MemAlloc.h"
22#include "llvm/Support/ReverseIteration.h"
23#include "llvm/Support/type_traits.h"
24#include <algorithm>
25#include <cassert>
26#include <cstddef>
27#include <cstring>
28#include <initializer_list>
29#include <iterator>
30#include <new>
31#include <type_traits>
32#include <utility>
33
34namespace llvm {
35
36namespace detail {
37
38// We extend a pair to allow users to override the bucket type with their own
39// implementation without requiring two members.
40template <typename KeyT, typename ValueT>
41struct DenseMapPair : public std::pair<KeyT, ValueT> {
42 using std::pair<KeyT, ValueT>::pair;
43
44 KeyT &getFirst() { return std::pair<KeyT, ValueT>::first; }
45 const KeyT &getFirst() const { return std::pair<KeyT, ValueT>::first; }
46 ValueT &getSecond() { return std::pair<KeyT, ValueT>::second; }
47 const ValueT &getSecond() const { return std::pair<KeyT, ValueT>::second; }
48};
49
50} // end namespace detail
51
52template <typename KeyT, typename ValueT,
53 typename KeyInfoT = DenseMapInfo<KeyT>,
54 typename Bucket = llvm::detail::DenseMapPair<KeyT, ValueT>,
55 bool IsConst = false>
56class DenseMapIterator;
57
58template <typename DerivedT, typename KeyT, typename ValueT, typename KeyInfoT,
59 typename BucketT>
60class DenseMapBase : public DebugEpochBase {
61 template <typename T>
62 using const_arg_type_t = typename const_pointer_or_const_ref<T>::type;
63
64public:
65 using size_type = unsigned;
66 using key_type = KeyT;
67 using mapped_type = ValueT;
68 using value_type = BucketT;
69
70 using iterator = DenseMapIterator<KeyT, ValueT, KeyInfoT, BucketT>;
71 using const_iterator =
72 DenseMapIterator<KeyT, ValueT, KeyInfoT, BucketT, true>;
73
74 inline iterator begin() {
75 // When the map is empty, avoid the overhead of advancing/retreating past
76 // empty buckets.
77 if (empty())
78 return end();
79 if (shouldReverseIterate<KeyT>())
80 return makeIterator(getBucketsEnd() - 1, getBuckets(), *this);
81 return makeIterator(getBuckets(), getBucketsEnd(), *this);
82 }
83 inline iterator end() {
84 return makeIterator(getBucketsEnd(), getBucketsEnd(), *this, true);
85 }
86 inline const_iterator begin() const {
87 if (empty())
88 return end();
89 if (shouldReverseIterate<KeyT>())
90 return makeConstIterator(getBucketsEnd() - 1, getBuckets(), *this);
91 return makeConstIterator(getBuckets(), getBucketsEnd(), *this);
92 }
93 inline const_iterator end() const {
94 return makeConstIterator(getBucketsEnd(), getBucketsEnd(), *this, true);
95 }
96
97 LLVM_NODISCARD[[clang::warn_unused_result]] bool empty() const {
98 return getNumEntries() == 0;
99 }
100 unsigned size() const { return getNumEntries(); }
101
102 /// Grow the densemap so that it can contain at least \p NumEntries items
103 /// before resizing again.
104 void reserve(size_type NumEntries) {
105 auto NumBuckets = getMinBucketToReserveForEntries(NumEntries);
106 incrementEpoch();
107 if (NumBuckets > getNumBuckets())
108 grow(NumBuckets);
109 }
110
111 void clear() {
112 incrementEpoch();
113 if (getNumEntries() == 0 && getNumTombstones() == 0) return;
114
115 // If the capacity of the array is huge, and the # elements used is small,
116 // shrink the array.
117 if (getNumEntries() * 4 < getNumBuckets() && getNumBuckets() > 64) {
118 shrink_and_clear();
119 return;
120 }
121
122 const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
123 if (std::is_trivially_destructible<ValueT>::value) {
124 // Use a simpler loop when values don't need destruction.
125 for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P)
126 P->getFirst() = EmptyKey;
127 } else {
128 unsigned NumEntries = getNumEntries();
129 for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) {
130 if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey)) {
131 if (!KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) {
132 P->getSecond().~ValueT();
133 --NumEntries;
134 }
135 P->getFirst() = EmptyKey;
136 }
137 }
138 assert(NumEntries == 0 && "Node count imbalance!")((void)0);
139 }
140 setNumEntries(0);
141 setNumTombstones(0);
142 }
143
144 /// Return 1 if the specified key is in the map, 0 otherwise.
145 size_type count(const_arg_type_t<KeyT> Val) const {
146 const BucketT *TheBucket;
147 return LookupBucketFor(Val, TheBucket) ? 1 : 0;
148 }
149
150 iterator find(const_arg_type_t<KeyT> Val) {
151 BucketT *TheBucket;
152 if (LookupBucketFor(Val, TheBucket))
153 return makeIterator(TheBucket,
154 shouldReverseIterate<KeyT>() ? getBuckets()
155 : getBucketsEnd(),
156 *this, true);
157 return end();
158 }
159 const_iterator find(const_arg_type_t<KeyT> Val) const {
160 const BucketT *TheBucket;
161 if (LookupBucketFor(Val, TheBucket))
162 return makeConstIterator(TheBucket,
163 shouldReverseIterate<KeyT>() ? getBuckets()
164 : getBucketsEnd(),
165 *this, true);
166 return end();
167 }
168
169 /// Alternate version of find() which allows a different, and possibly
170 /// less expensive, key type.
171 /// The DenseMapInfo is responsible for supplying methods
172 /// getHashValue(LookupKeyT) and isEqual(LookupKeyT, KeyT) for each key
173 /// type used.
174 template<class LookupKeyT>
175 iterator find_as(const LookupKeyT &Val) {
176 BucketT *TheBucket;
177 if (LookupBucketFor(Val, TheBucket))
178 return makeIterator(TheBucket,
179 shouldReverseIterate<KeyT>() ? getBuckets()
180 : getBucketsEnd(),
181 *this, true);
182 return end();
183 }
184 template<class LookupKeyT>
185 const_iterator find_as(const LookupKeyT &Val) const {
186 const BucketT *TheBucket;
187 if (LookupBucketFor(Val, TheBucket))
188 return makeConstIterator(TheBucket,
189 shouldReverseIterate<KeyT>() ? getBuckets()
190 : getBucketsEnd(),
191 *this, true);
192 return end();
193 }
194
195 /// lookup - Return the entry for the specified key, or a default
196 /// constructed value if no such entry exists.
197 ValueT lookup(const_arg_type_t<KeyT> Val) const {
198 const BucketT *TheBucket;
199 if (LookupBucketFor(Val, TheBucket))
200 return TheBucket->getSecond();
201 return ValueT();
202 }
203
204 // Inserts key,value pair into the map if the key isn't already in the map.
205 // If the key is already in the map, it returns false and doesn't update the
206 // value.
207 std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &KV) {
208 return try_emplace(KV.first, KV.second);
209 }
210
211 // Inserts key,value pair into the map if the key isn't already in the map.
212 // If the key is already in the map, it returns false and doesn't update the
213 // value.
214 std::pair<iterator, bool> insert(std::pair<KeyT, ValueT> &&KV) {
215 return try_emplace(std::move(KV.first), std::move(KV.second));
216 }
217
218 // Inserts key,value pair into the map if the key isn't already in the map.
219 // The value is constructed in-place if the key is not in the map, otherwise
220 // it is not moved.
221 template <typename... Ts>
222 std::pair<iterator, bool> try_emplace(KeyT &&Key, Ts &&... Args) {
223 BucketT *TheBucket;
224 if (LookupBucketFor(Key, TheBucket))
225 return std::make_pair(makeIterator(TheBucket,
226 shouldReverseIterate<KeyT>()
227 ? getBuckets()
228 : getBucketsEnd(),
229 *this, true),
230 false); // Already in map.
231
232 // Otherwise, insert the new element.
233 TheBucket =
234 InsertIntoBucket(TheBucket, std::move(Key), std::forward<Ts>(Args)...);
235 return std::make_pair(makeIterator(TheBucket,
236 shouldReverseIterate<KeyT>()
237 ? getBuckets()
238 : getBucketsEnd(),
239 *this, true),
240 true);
241 }
242
243 // Inserts key,value pair into the map if the key isn't already in the map.
244 // The value is constructed in-place if the key is not in the map, otherwise
245 // it is not moved.
246 template <typename... Ts>
247 std::pair<iterator, bool> try_emplace(const KeyT &Key, Ts &&... Args) {
248 BucketT *TheBucket;
249 if (LookupBucketFor(Key, TheBucket))
250 return std::make_pair(makeIterator(TheBucket,
251 shouldReverseIterate<KeyT>()
252 ? getBuckets()
253 : getBucketsEnd(),
254 *this, true),
255 false); // Already in map.
256
257 // Otherwise, insert the new element.
258 TheBucket = InsertIntoBucket(TheBucket, Key, std::forward<Ts>(Args)...);
259 return std::make_pair(makeIterator(TheBucket,
260 shouldReverseIterate<KeyT>()
261 ? getBuckets()
262 : getBucketsEnd(),
263 *this, true),
264 true);
265 }
266
267 /// Alternate version of insert() which allows a different, and possibly
268 /// less expensive, key type.
269 /// The DenseMapInfo is responsible for supplying methods
270 /// getHashValue(LookupKeyT) and isEqual(LookupKeyT, KeyT) for each key
271 /// type used.
272 template <typename LookupKeyT>
273 std::pair<iterator, bool> insert_as(std::pair<KeyT, ValueT> &&KV,
274 const LookupKeyT &Val) {
275 BucketT *TheBucket;
276 if (LookupBucketFor(Val, TheBucket))
277 return std::make_pair(makeIterator(TheBucket,
278 shouldReverseIterate<KeyT>()
279 ? getBuckets()
280 : getBucketsEnd(),
281 *this, true),
282 false); // Already in map.
283
284 // Otherwise, insert the new element.
285 TheBucket = InsertIntoBucketWithLookup(TheBucket, std::move(KV.first),
286 std::move(KV.second), Val);
287 return std::make_pair(makeIterator(TheBucket,
288 shouldReverseIterate<KeyT>()
289 ? getBuckets()
290 : getBucketsEnd(),
291 *this, true),
292 true);
293 }
294
295 /// insert - Range insertion of pairs.
296 template<typename InputIt>
297 void insert(InputIt I, InputIt E) {
298 for (; I != E; ++I)
299 insert(*I);
300 }
301
302 bool erase(const KeyT &Val) {
303 BucketT *TheBucket;
304 if (!LookupBucketFor(Val, TheBucket))
305 return false; // not in map.
306
307 TheBucket->getSecond().~ValueT();
308 TheBucket->getFirst() = getTombstoneKey();
309 decrementNumEntries();
310 incrementNumTombstones();
311 return true;
312 }
313 void erase(iterator I) {
314 BucketT *TheBucket = &*I;
315 TheBucket->getSecond().~ValueT();
316 TheBucket->getFirst() = getTombstoneKey();
317 decrementNumEntries();
318 incrementNumTombstones();
319 }
320
321 value_type& FindAndConstruct(const KeyT &Key) {
322 BucketT *TheBucket;
323 if (LookupBucketFor(Key, TheBucket))
324 return *TheBucket;
325
326 return *InsertIntoBucket(TheBucket, Key);
327 }
328
329 ValueT &operator[](const KeyT &Key) {
330 return FindAndConstruct(Key).second;
331 }
332
333 value_type& FindAndConstruct(KeyT &&Key) {
334 BucketT *TheBucket;
335 if (LookupBucketFor(Key, TheBucket))
336 return *TheBucket;
337
338 return *InsertIntoBucket(TheBucket, std::move(Key));
339 }
340
341 ValueT &operator[](KeyT &&Key) {
342 return FindAndConstruct(std::move(Key)).second;
343 }
344
345 /// isPointerIntoBucketsArray - Return true if the specified pointer points
346 /// somewhere into the DenseMap's array of buckets (i.e. either to a key or
347 /// value in the DenseMap).
348 bool isPointerIntoBucketsArray(const void *Ptr) const {
349 return Ptr >= getBuckets() && Ptr < getBucketsEnd();
350 }
351
352 /// getPointerIntoBucketsArray() - Return an opaque pointer into the buckets
353 /// array. In conjunction with the previous method, this can be used to
354 /// determine whether an insertion caused the DenseMap to reallocate.
355 const void *getPointerIntoBucketsArray() const { return getBuckets(); }
356
357protected:
358 DenseMapBase() = default;
359
360 void destroyAll() {
361 if (getNumBuckets() == 0) // Nothing to do.
362 return;
363
364 const KeyT EmptyKey = getEmptyKey(), TombstoneKey = getTombstoneKey();
365 for (BucketT *P = getBuckets(), *E = getBucketsEnd(); P != E; ++P) {
366 if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey) &&
367 !KeyInfoT::isEqual(P->getFirst(), TombstoneKey))
368 P->getSecond().~ValueT();
369 P->getFirst().~KeyT();
370 }
371 }
372
373 void initEmpty() {
374 setNumEntries(0);
375 setNumTombstones(0);
376
377 assert((getNumBuckets() & (getNumBuckets()-1)) == 0 &&((void)0)
378 "# initial buckets must be a power of two!")((void)0);
379 const KeyT EmptyKey = getEmptyKey();
380 for (BucketT *B = getBuckets(), *E = getBucketsEnd(); B != E; ++B)
381 ::new (&B->getFirst()) KeyT(EmptyKey);
382 }
383
384 /// Returns the number of buckets to allocate to ensure that the DenseMap can
385 /// accommodate \p NumEntries without need to grow().
386 unsigned getMinBucketToReserveForEntries(unsigned NumEntries) {
387 // Ensure that "NumEntries * 4 < NumBuckets * 3"
388 if (NumEntries == 0)
389 return 0;
390 // +1 is required because of the strict equality.
391 // For example if NumEntries is 48, we need to return 401.
392 return NextPowerOf2(NumEntries * 4 / 3 + 1);
393 }
394
395 void moveFromOldBuckets(BucketT *OldBucketsBegin, BucketT *OldBucketsEnd) {
396 initEmpty();
397
398 // Insert all the old elements.
399 const KeyT EmptyKey = getEmptyKey();
400 const KeyT TombstoneKey = getTombstoneKey();
401 for (BucketT *B = OldBucketsBegin, *E = OldBucketsEnd; B != E; ++B) {
402 if (!KeyInfoT::isEqual(B->getFirst(), EmptyKey) &&
403 !KeyInfoT::isEqual(B->getFirst(), TombstoneKey)) {
404 // Insert the key/value into the new table.
405 BucketT *DestBucket;
406 bool FoundVal = LookupBucketFor(B->getFirst(), DestBucket);
407 (void)FoundVal; // silence warning.
408 assert(!FoundVal && "Key already in new map?")((void)0);
409 DestBucket->getFirst() = std::move(B->getFirst());
410 ::new (&DestBucket->getSecond()) ValueT(std::move(B->getSecond()));
411 incrementNumEntries();
412
413 // Free the value.
414 B->getSecond().~ValueT();
415 }
416 B->getFirst().~KeyT();
417 }
418 }
419
420 template <typename OtherBaseT>
421 void copyFrom(
422 const DenseMapBase<OtherBaseT, KeyT, ValueT, KeyInfoT, BucketT> &other) {
423 assert(&other != this)((void)0);
424 assert(getNumBuckets() == other.getNumBuckets())((void)0);
425
426 setNumEntries(other.getNumEntries());
427 setNumTombstones(other.getNumTombstones());
428
429 if (std::is_trivially_copyable<KeyT>::value &&
430 std::is_trivially_copyable<ValueT>::value)
431 memcpy(reinterpret_cast<void *>(getBuckets()), other.getBuckets(),
432 getNumBuckets() * sizeof(BucketT));
433 else
434 for (size_t i = 0; i < getNumBuckets(); ++i) {
435 ::new (&getBuckets()[i].getFirst())
436 KeyT(other.getBuckets()[i].getFirst());
437 if (!KeyInfoT::isEqual(getBuckets()[i].getFirst(), getEmptyKey()) &&
438 !KeyInfoT::isEqual(getBuckets()[i].getFirst(), getTombstoneKey()))
439 ::new (&getBuckets()[i].getSecond())
440 ValueT(other.getBuckets()[i].getSecond());
441 }
442 }
443
444 static unsigned getHashValue(const KeyT &Val) {
445 return KeyInfoT::getHashValue(Val);
446 }
447
448 template<typename LookupKeyT>
449 static unsigned getHashValue(const LookupKeyT &Val) {
450 return KeyInfoT::getHashValue(Val);
451 }
452
453 static const KeyT getEmptyKey() {
454 static_assert(std::is_base_of<DenseMapBase, DerivedT>::value,
455 "Must pass the derived type to this template!");
456 return KeyInfoT::getEmptyKey();
457 }
458
459 static const KeyT getTombstoneKey() {
460 return KeyInfoT::getTombstoneKey();
461 }
462
463private:
464 iterator makeIterator(BucketT *P, BucketT *E,
465 DebugEpochBase &Epoch,
466 bool NoAdvance=false) {
467 if (shouldReverseIterate<KeyT>()) {
468 BucketT *B = P == getBucketsEnd() ? getBuckets() : P + 1;
469 return iterator(B, E, Epoch, NoAdvance);
470 }
471 return iterator(P, E, Epoch, NoAdvance);
472 }
473
474 const_iterator makeConstIterator(const BucketT *P, const BucketT *E,
475 const DebugEpochBase &Epoch,
476 const bool NoAdvance=false) const {
477 if (shouldReverseIterate<KeyT>()) {
478 const BucketT *B = P == getBucketsEnd() ? getBuckets() : P + 1;
479 return const_iterator(B, E, Epoch, NoAdvance);
480 }
481 return const_iterator(P, E, Epoch, NoAdvance);
482 }
483
484 unsigned getNumEntries() const {
485 return static_cast<const DerivedT *>(this)->getNumEntries();
486 }
487
488 void setNumEntries(unsigned Num) {
489 static_cast<DerivedT *>(this)->setNumEntries(Num);
490 }
491
492 void incrementNumEntries() {
493 setNumEntries(getNumEntries() + 1);
494 }
495
496 void decrementNumEntries() {
497 setNumEntries(getNumEntries() - 1);
498 }
499
500 unsigned getNumTombstones() const {
501 return static_cast<const DerivedT *>(this)->getNumTombstones();
502 }
503
504 void setNumTombstones(unsigned Num) {
505 static_cast<DerivedT *>(this)->setNumTombstones(Num);
506 }
507
508 void incrementNumTombstones() {
509 setNumTombstones(getNumTombstones() + 1);
510 }
511
512 void decrementNumTombstones() {
513 setNumTombstones(getNumTombstones() - 1);
514 }
515
516 const BucketT *getBuckets() const {
517 return static_cast<const DerivedT *>(this)->getBuckets();
518 }
519
520 BucketT *getBuckets() {
521 return static_cast<DerivedT *>(this)->getBuckets();
522 }
523
524 unsigned getNumBuckets() const {
525 return static_cast<const DerivedT *>(this)->getNumBuckets();
526 }
527
528 BucketT *getBucketsEnd() {
529 return getBuckets() + getNumBuckets();
530 }
531
532 const BucketT *getBucketsEnd() const {
533 return getBuckets() + getNumBuckets();
534 }
535
536 void grow(unsigned AtLeast) {
537 static_cast<DerivedT *>(this)->grow(AtLeast);
538 }
539
540 void shrink_and_clear() {
541 static_cast<DerivedT *>(this)->shrink_and_clear();
542 }
543
544 template <typename KeyArg, typename... ValueArgs>
545 BucketT *InsertIntoBucket(BucketT *TheBucket, KeyArg &&Key,
546 ValueArgs &&... Values) {
547 TheBucket = InsertIntoBucketImpl(Key, Key, TheBucket);
548
549 TheBucket->getFirst() = std::forward<KeyArg>(Key);
550 ::new (&TheBucket->getSecond()) ValueT(std::forward<ValueArgs>(Values)...);
551 return TheBucket;
552 }
553
554 template <typename LookupKeyT>
555 BucketT *InsertIntoBucketWithLookup(BucketT *TheBucket, KeyT &&Key,
556 ValueT &&Value, LookupKeyT &Lookup) {
557 TheBucket = InsertIntoBucketImpl(Key, Lookup, TheBucket);
558
559 TheBucket->getFirst() = std::move(Key);
560 ::new (&TheBucket->getSecond()) ValueT(std::move(Value));
561 return TheBucket;
562 }
563
564 template <typename LookupKeyT>
565 BucketT *InsertIntoBucketImpl(const KeyT &Key, const LookupKeyT &Lookup,
566 BucketT *TheBucket) {
567 incrementEpoch();
568
569 // If the load of the hash table is more than 3/4, or if fewer than 1/8 of
570 // the buckets are empty (meaning that many are filled with tombstones),
571 // grow the table.
572 //
573 // The later case is tricky. For example, if we had one empty bucket with
574 // tons of tombstones, failing lookups (e.g. for insertion) would have to
575 // probe almost the entire table until it found the empty bucket. If the
576 // table completely filled with tombstones, no lookup would ever succeed,
577 // causing infinite loops in lookup.
578 unsigned NewNumEntries = getNumEntries() + 1;
579 unsigned NumBuckets = getNumBuckets();
580 if (LLVM_UNLIKELY(NewNumEntries * 4 >= NumBuckets * 3)__builtin_expect((bool)(NewNumEntries * 4 >= NumBuckets * 3
), false)
) {
581 this->grow(NumBuckets * 2);
582 LookupBucketFor(Lookup, TheBucket);
583 NumBuckets = getNumBuckets();
584 } else if (LLVM_UNLIKELY(NumBuckets-(NewNumEntries+getNumTombstones()) <=__builtin_expect((bool)(NumBuckets-(NewNumEntries+getNumTombstones
()) <= NumBuckets/8), false)
585 NumBuckets/8)__builtin_expect((bool)(NumBuckets-(NewNumEntries+getNumTombstones
()) <= NumBuckets/8), false)
) {
586 this->grow(NumBuckets);
587 LookupBucketFor(Lookup, TheBucket);
588 }
589 assert(TheBucket)((void)0);
590
591 // Only update the state after we've grown our bucket space appropriately
592 // so that when growing buckets we have self-consistent entry count.
593 incrementNumEntries();
594
595 // If we are writing over a tombstone, remember this.
596 const KeyT EmptyKey = getEmptyKey();
597 if (!KeyInfoT::isEqual(TheBucket->getFirst(), EmptyKey))
598 decrementNumTombstones();
599
600 return TheBucket;
601 }
602
603 /// LookupBucketFor - Lookup the appropriate bucket for Val, returning it in
604 /// FoundBucket. If the bucket contains the key and a value, this returns
605 /// true, otherwise it returns a bucket with an empty marker or tombstone and
606 /// returns false.
607 template<typename LookupKeyT>
608 bool LookupBucketFor(const LookupKeyT &Val,
609 const BucketT *&FoundBucket) const {
610 const BucketT *BucketsPtr = getBuckets();
611 const unsigned NumBuckets = getNumBuckets();
612
613 if (NumBuckets == 0) {
614 FoundBucket = nullptr;
615 return false;
616 }
617
618 // FoundTombstone - Keep track of whether we find a tombstone while probing.
619 const BucketT *FoundTombstone = nullptr;
620 const KeyT EmptyKey = getEmptyKey();
621 const KeyT TombstoneKey = getTombstoneKey();
622 assert(!KeyInfoT::isEqual(Val, EmptyKey) &&((void)0)
623 !KeyInfoT::isEqual(Val, TombstoneKey) &&((void)0)
624 "Empty/Tombstone value shouldn't be inserted into map!")((void)0);
625
626 unsigned BucketNo = getHashValue(Val) & (NumBuckets-1);
627 unsigned ProbeAmt = 1;
628 while (true) {
629 const BucketT *ThisBucket = BucketsPtr + BucketNo;
630 // Found Val's bucket? If so, return it.
631 if (LLVM_LIKELY(KeyInfoT::isEqual(Val, ThisBucket->getFirst()))__builtin_expect((bool)(KeyInfoT::isEqual(Val, ThisBucket->
getFirst())), true)
) {
632 FoundBucket = ThisBucket;
633 return true;
634 }
635
636 // If we found an empty bucket, the key doesn't exist in the set.
637 // Insert it and return the default value.
638 if (LLVM_LIKELY(KeyInfoT::isEqual(ThisBucket->getFirst(), EmptyKey))__builtin_expect((bool)(KeyInfoT::isEqual(ThisBucket->getFirst
(), EmptyKey)), true)
) {
639 // If we've already seen a tombstone while probing, fill it in instead
640 // of the empty bucket we eventually probed to.
641 FoundBucket = FoundTombstone ? FoundTombstone : ThisBucket;
642 return false;
643 }
644
645 // If this is a tombstone, remember it. If Val ends up not in the map, we
646 // prefer to return it than something that would require more probing.
647 if (KeyInfoT::isEqual(ThisBucket->getFirst(), TombstoneKey) &&
648 !FoundTombstone)
649 FoundTombstone = ThisBucket; // Remember the first tombstone found.
650
651 // Otherwise, it's a hash collision or a tombstone, continue quadratic
652 // probing.
653 BucketNo += ProbeAmt++;
654 BucketNo &= (NumBuckets-1);
655 }
656 }
657
658 template <typename LookupKeyT>
659 bool LookupBucketFor(const LookupKeyT &Val, BucketT *&FoundBucket) {
660 const BucketT *ConstFoundBucket;
661 bool Result = const_cast<const DenseMapBase *>(this)
662 ->LookupBucketFor(Val, ConstFoundBucket);
663 FoundBucket = const_cast<BucketT *>(ConstFoundBucket);
664 return Result;
665 }
666
667public:
668 /// Return the approximate size (in bytes) of the actual map.
669 /// This is just the raw memory used by DenseMap.
670 /// If entries are pointers to objects, the size of the referenced objects
671 /// are not included.
672 size_t getMemorySize() const {
673 return getNumBuckets() * sizeof(BucketT);
674 }
675};
676
677/// Equality comparison for DenseMap.
678///
679/// Iterates over elements of LHS confirming that each (key, value) pair in LHS
680/// is also in RHS, and that no additional pairs are in RHS.
681/// Equivalent to N calls to RHS.find and N value comparisons. Amortized
682/// complexity is linear, worst case is O(N^2) (if every hash collides).
683template <typename DerivedT, typename KeyT, typename ValueT, typename KeyInfoT,
684 typename BucketT>
685bool operator==(
686 const DenseMapBase<DerivedT, KeyT, ValueT, KeyInfoT, BucketT> &LHS,
687 const DenseMapBase<DerivedT, KeyT, ValueT, KeyInfoT, BucketT> &RHS) {
688 if (LHS.size() != RHS.size())
689 return false;
690
691 for (auto &KV : LHS) {
692 auto I = RHS.find(KV.first);
693 if (I == RHS.end() || I->second != KV.second)
694 return false;
695 }
696
697 return true;
698}
699
700/// Inequality comparison for DenseMap.
701///
702/// Equivalent to !(LHS == RHS). See operator== for performance notes.
703template <typename DerivedT, typename KeyT, typename ValueT, typename KeyInfoT,
704 typename BucketT>
705bool operator!=(
706 const DenseMapBase<DerivedT, KeyT, ValueT, KeyInfoT, BucketT> &LHS,
707 const DenseMapBase<DerivedT, KeyT, ValueT, KeyInfoT, BucketT> &RHS) {
708 return !(LHS == RHS);
709}
710
711template <typename KeyT, typename ValueT,
712 typename KeyInfoT = DenseMapInfo<KeyT>,
713 typename BucketT = llvm::detail::DenseMapPair<KeyT, ValueT>>
714class DenseMap : public DenseMapBase<DenseMap<KeyT, ValueT, KeyInfoT, BucketT>,
715 KeyT, ValueT, KeyInfoT, BucketT> {
716 friend class DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
717
718 // Lift some types from the dependent base class into this class for
719 // simplicity of referring to them.
720 using BaseT = DenseMapBase<DenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
721
722 BucketT *Buckets;
723 unsigned NumEntries;
724 unsigned NumTombstones;
725 unsigned NumBuckets;
726
727public:
728 /// Create a DenseMap with an optional \p InitialReserve that guarantee that
729 /// this number of elements can be inserted in the map without grow()
730 explicit DenseMap(unsigned InitialReserve = 0) { init(InitialReserve); }
731
732 DenseMap(const DenseMap &other) : BaseT() {
733 init(0);
734 copyFrom(other);
735 }
736
737 DenseMap(DenseMap &&other) : BaseT() {
738 init(0);
739 swap(other);
740 }
741
742 template<typename InputIt>
743 DenseMap(const InputIt &I, const InputIt &E) {
744 init(std::distance(I, E));
745 this->insert(I, E);
746 }
747
748 DenseMap(std::initializer_list<typename BaseT::value_type> Vals) {
749 init(Vals.size());
750 this->insert(Vals.begin(), Vals.end());
751 }
752
753 ~DenseMap() {
754 this->destroyAll();
755 deallocate_buffer(Buckets, sizeof(BucketT) * NumBuckets, alignof(BucketT));
756 }
757
758 void swap(DenseMap& RHS) {
759 this->incrementEpoch();
760 RHS.incrementEpoch();
761 std::swap(Buckets, RHS.Buckets);
762 std::swap(NumEntries, RHS.NumEntries);
763 std::swap(NumTombstones, RHS.NumTombstones);
764 std::swap(NumBuckets, RHS.NumBuckets);
765 }
766
767 DenseMap& operator=(const DenseMap& other) {
768 if (&other != this)
769 copyFrom(other);
770 return *this;
771 }
772
773 DenseMap& operator=(DenseMap &&other) {
774 this->destroyAll();
775 deallocate_buffer(Buckets, sizeof(BucketT) * NumBuckets, alignof(BucketT));
776 init(0);
777 swap(other);
778 return *this;
779 }
780
781 void copyFrom(const DenseMap& other) {
782 this->destroyAll();
783 deallocate_buffer(Buckets, sizeof(BucketT) * NumBuckets, alignof(BucketT));
784 if (allocateBuckets(other.NumBuckets)) {
785 this->BaseT::copyFrom(other);
786 } else {
787 NumEntries = 0;
788 NumTombstones = 0;
789 }
790 }
791
792 void init(unsigned InitNumEntries) {
793 auto InitBuckets = BaseT::getMinBucketToReserveForEntries(InitNumEntries);
794 if (allocateBuckets(InitBuckets)) {
795 this->BaseT::initEmpty();
796 } else {
797 NumEntries = 0;
798 NumTombstones = 0;
799 }
800 }
801
802 void grow(unsigned AtLeast) {
803 unsigned OldNumBuckets = NumBuckets;
804 BucketT *OldBuckets = Buckets;
805
806 allocateBuckets(std::max<unsigned>(64, static_cast<unsigned>(NextPowerOf2(AtLeast-1))));
807 assert(Buckets)((void)0);
808 if (!OldBuckets) {
809 this->BaseT::initEmpty();
810 return;
811 }
812
813 this->moveFromOldBuckets(OldBuckets, OldBuckets+OldNumBuckets);
814
815 // Free the old table.
816 deallocate_buffer(OldBuckets, sizeof(BucketT) * OldNumBuckets,
817 alignof(BucketT));
818 }
819
820 void shrink_and_clear() {
821 unsigned OldNumBuckets = NumBuckets;
822 unsigned OldNumEntries = NumEntries;
823 this->destroyAll();
824
825 // Reduce the number of buckets.
826 unsigned NewNumBuckets = 0;
827 if (OldNumEntries)
828 NewNumBuckets = std::max(64, 1 << (Log2_32_Ceil(OldNumEntries) + 1));
829 if (NewNumBuckets == NumBuckets) {
830 this->BaseT::initEmpty();
831 return;
832 }
833
834 deallocate_buffer(Buckets, sizeof(BucketT) * OldNumBuckets,
835 alignof(BucketT));
836 init(NewNumBuckets);
837 }
838
839private:
840 unsigned getNumEntries() const {
841 return NumEntries;
842 }
843
844 void setNumEntries(unsigned Num) {
845 NumEntries = Num;
846 }
847
848 unsigned getNumTombstones() const {
849 return NumTombstones;
850 }
851
852 void setNumTombstones(unsigned Num) {
853 NumTombstones = Num;
854 }
855
856 BucketT *getBuckets() const {
857 return Buckets;
858 }
859
860 unsigned getNumBuckets() const {
861 return NumBuckets;
862 }
863
864 bool allocateBuckets(unsigned Num) {
865 NumBuckets = Num;
866 if (NumBuckets == 0) {
867 Buckets = nullptr;
868 return false;
869 }
870
871 Buckets = static_cast<BucketT *>(
872 allocate_buffer(sizeof(BucketT) * NumBuckets, alignof(BucketT)));
873 return true;
874 }
875};
876
877template <typename KeyT, typename ValueT, unsigned InlineBuckets = 4,
878 typename KeyInfoT = DenseMapInfo<KeyT>,
879 typename BucketT = llvm::detail::DenseMapPair<KeyT, ValueT>>
880class SmallDenseMap
881 : public DenseMapBase<
882 SmallDenseMap<KeyT, ValueT, InlineBuckets, KeyInfoT, BucketT>, KeyT,
883 ValueT, KeyInfoT, BucketT> {
884 friend class DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
885
886 // Lift some types from the dependent base class into this class for
887 // simplicity of referring to them.
888 using BaseT = DenseMapBase<SmallDenseMap, KeyT, ValueT, KeyInfoT, BucketT>;
889
890 static_assert(isPowerOf2_64(InlineBuckets),
891 "InlineBuckets must be a power of 2.");
892
893 unsigned Small : 1;
894 unsigned NumEntries : 31;
895 unsigned NumTombstones;
896
897 struct LargeRep {
898 BucketT *Buckets;
899 unsigned NumBuckets;
900 };
901
902 /// A "union" of an inline bucket array and the struct representing
903 /// a large bucket. This union will be discriminated by the 'Small' bit.
904 AlignedCharArrayUnion<BucketT[InlineBuckets], LargeRep> storage;
905
906public:
907 explicit SmallDenseMap(unsigned NumInitBuckets = 0) {
908 init(NumInitBuckets);
909 }
910
911 SmallDenseMap(const SmallDenseMap &other) : BaseT() {
912 init(0);
913 copyFrom(other);
914 }
915
916 SmallDenseMap(SmallDenseMap &&other) : BaseT() {
917 init(0);
918 swap(other);
919 }
920
921 template<typename InputIt>
922 SmallDenseMap(const InputIt &I, const InputIt &E) {
923 init(NextPowerOf2(std::distance(I, E)));
924 this->insert(I, E);
925 }
926
927 SmallDenseMap(std::initializer_list<typename BaseT::value_type> Vals)
928 : SmallDenseMap(Vals.begin(), Vals.end()) {}
929
930 ~SmallDenseMap() {
931 this->destroyAll();
932 deallocateBuckets();
933 }
934
935 void swap(SmallDenseMap& RHS) {
936 unsigned TmpNumEntries = RHS.NumEntries;
937 RHS.NumEntries = NumEntries;
938 NumEntries = TmpNumEntries;
939 std::swap(NumTombstones, RHS.NumTombstones);
940
941 const KeyT EmptyKey = this->getEmptyKey();
942 const KeyT TombstoneKey = this->getTombstoneKey();
943 if (Small && RHS.Small) {
944 // If we're swapping inline bucket arrays, we have to cope with some of
945 // the tricky bits of DenseMap's storage system: the buckets are not
946 // fully initialized. Thus we swap every key, but we may have
947 // a one-directional move of the value.
948 for (unsigned i = 0, e = InlineBuckets; i != e; ++i) {
949 BucketT *LHSB = &getInlineBuckets()[i],
950 *RHSB = &RHS.getInlineBuckets()[i];
951 bool hasLHSValue = (!KeyInfoT::isEqual(LHSB->getFirst(), EmptyKey) &&
952 !KeyInfoT::isEqual(LHSB->getFirst(), TombstoneKey));
953 bool hasRHSValue = (!KeyInfoT::isEqual(RHSB->getFirst(), EmptyKey) &&
954 !KeyInfoT::isEqual(RHSB->getFirst(), TombstoneKey));
955 if (hasLHSValue && hasRHSValue) {
956 // Swap together if we can...
957 std::swap(*LHSB, *RHSB);
958 continue;
959 }
960 // Swap separately and handle any asymmetry.
961 std::swap(LHSB->getFirst(), RHSB->getFirst());
962 if (hasLHSValue) {
963 ::new (&RHSB->getSecond()) ValueT(std::move(LHSB->getSecond()));
964 LHSB->getSecond().~ValueT();
965 } else if (hasRHSValue) {
966 ::new (&LHSB->getSecond()) ValueT(std::move(RHSB->getSecond()));
967 RHSB->getSecond().~ValueT();
968 }
969 }
970 return;
971 }
972 if (!Small && !RHS.Small) {
973 std::swap(getLargeRep()->Buckets, RHS.getLargeRep()->Buckets);
974 std::swap(getLargeRep()->NumBuckets, RHS.getLargeRep()->NumBuckets);
975 return;
976 }
977
978 SmallDenseMap &SmallSide = Small ? *this : RHS;
979 SmallDenseMap &LargeSide = Small ? RHS : *this;
980
981 // First stash the large side's rep and move the small side across.
982 LargeRep TmpRep = std::move(*LargeSide.getLargeRep());
983 LargeSide.getLargeRep()->~LargeRep();
984 LargeSide.Small = true;
985 // This is similar to the standard move-from-old-buckets, but the bucket
986 // count hasn't actually rotated in this case. So we have to carefully
987 // move construct the keys and values into their new locations, but there
988 // is no need to re-hash things.
989 for (unsigned i = 0, e = InlineBuckets; i != e; ++i) {
990 BucketT *NewB = &LargeSide.getInlineBuckets()[i],
991 *OldB = &SmallSide.getInlineBuckets()[i];
992 ::new (&NewB->getFirst()) KeyT(std::move(OldB->getFirst()));
993 OldB->getFirst().~KeyT();
994 if (!KeyInfoT::isEqual(NewB->getFirst(), EmptyKey) &&
995 !KeyInfoT::isEqual(NewB->getFirst(), TombstoneKey)) {
996 ::new (&NewB->getSecond()) ValueT(std::move(OldB->getSecond()));
997 OldB->getSecond().~ValueT();
998 }
999 }
1000
1001 // The hard part of moving the small buckets across is done, just move
1002 // the TmpRep into its new home.
1003 SmallSide.Small = false;
1004 new (SmallSide.getLargeRep()) LargeRep(std::move(TmpRep));
1005 }
1006
1007 SmallDenseMap& operator=(const SmallDenseMap& other) {
1008 if (&other != this)
1009 copyFrom(other);
1010 return *this;
1011 }
1012
1013 SmallDenseMap& operator=(SmallDenseMap &&other) {
1014 this->destroyAll();
1015 deallocateBuckets();
1016 init(0);
1017 swap(other);
1018 return *this;
1019 }
1020
1021 void copyFrom(const SmallDenseMap& other) {
1022 this->destroyAll();
1023 deallocateBuckets();
1024 Small = true;
1025 if (other.getNumBuckets() > InlineBuckets) {
1026 Small = false;
1027 new (getLargeRep()) LargeRep(allocateBuckets(other.getNumBuckets()));
1028 }
1029 this->BaseT::copyFrom(other);
1030 }
1031
1032 void init(unsigned InitBuckets) {
1033 Small = true;
1034 if (InitBuckets > InlineBuckets) {
1035 Small = false;
1036 new (getLargeRep()) LargeRep(allocateBuckets(InitBuckets));
1037 }
1038 this->BaseT::initEmpty();
1039 }
1040
1041 void grow(unsigned AtLeast) {
1042 if (AtLeast > InlineBuckets)
1043 AtLeast = std::max<unsigned>(64, NextPowerOf2(AtLeast-1));
1044
1045 if (Small) {
1046 // First move the inline buckets into a temporary storage.
1047 AlignedCharArrayUnion<BucketT[InlineBuckets]> TmpStorage;
1048 BucketT *TmpBegin = reinterpret_cast<BucketT *>(&TmpStorage);
1049 BucketT *TmpEnd = TmpBegin;
1050
1051 // Loop over the buckets, moving non-empty, non-tombstones into the
1052 // temporary storage. Have the loop move the TmpEnd forward as it goes.
1053 const KeyT EmptyKey = this->getEmptyKey();
1054 const KeyT TombstoneKey = this->getTombstoneKey();
1055 for (BucketT *P = getBuckets(), *E = P + InlineBuckets; P != E; ++P) {
1056 if (!KeyInfoT::isEqual(P->getFirst(), EmptyKey) &&
1057 !KeyInfoT::isEqual(P->getFirst(), TombstoneKey)) {
1058 assert(size_t(TmpEnd - TmpBegin) < InlineBuckets &&((void)0)
1059 "Too many inline buckets!")((void)0);
1060 ::new (&TmpEnd->getFirst()) KeyT(std::move(P->getFirst()));
1061 ::new (&TmpEnd->getSecond()) ValueT(std::move(P->getSecond()));
1062 ++TmpEnd;
1063 P->getSecond().~ValueT();
1064 }
1065 P->getFirst().~KeyT();
1066 }
1067
1068 // AtLeast == InlineBuckets can happen if there are many tombstones,
1069 // and grow() is used to remove them. Usually we always switch to the
1070 // large rep here.
1071 if (AtLeast > InlineBuckets) {
1072 Small = false;
1073 new (getLargeRep()) LargeRep(allocateBuckets(AtLeast));
1074 }
1075 this->moveFromOldBuckets(TmpBegin, TmpEnd);
1076 return;
1077 }
1078
1079 LargeRep OldRep = std::move(*getLargeRep());
1080 getLargeRep()->~LargeRep();
1081 if (AtLeast <= InlineBuckets) {
1082 Small = true;
1083 } else {
1084 new (getLargeRep()) LargeRep(allocateBuckets(AtLeast));
1085 }
1086
1087 this->moveFromOldBuckets(OldRep.Buckets, OldRep.Buckets+OldRep.NumBuckets);
1088
1089 // Free the old table.
1090 deallocate_buffer(OldRep.Buckets, sizeof(BucketT) * OldRep.NumBuckets,
1091 alignof(BucketT));
1092 }
1093
1094 void shrink_and_clear() {
1095 unsigned OldSize = this->size();
1096 this->destroyAll();
1097
1098 // Reduce the number of buckets.
1099 unsigned NewNumBuckets = 0;
1100 if (OldSize) {
1101 NewNumBuckets = 1 << (Log2_32_Ceil(OldSize) + 1);
1102 if (NewNumBuckets > InlineBuckets && NewNumBuckets < 64u)
1103 NewNumBuckets = 64;
1104 }
1105 if ((Small && NewNumBuckets <= InlineBuckets) ||
1106 (!Small && NewNumBuckets == getLargeRep()->NumBuckets)) {
1107 this->BaseT::initEmpty();
1108 return;
1109 }
1110
1111 deallocateBuckets();
1112 init(NewNumBuckets);
1113 }
1114
1115private:
1116 unsigned getNumEntries() const {
1117 return NumEntries;
1118 }
1119
1120 void setNumEntries(unsigned Num) {
1121 // NumEntries is hardcoded to be 31 bits wide.
1122 assert(Num < (1U << 31) && "Cannot support more than 1<<31 entries")((void)0);
1123 NumEntries = Num;
1124 }
1125
1126 unsigned getNumTombstones() const {
1127 return NumTombstones;
1128 }
1129
1130 void setNumTombstones(unsigned Num) {
1131 NumTombstones = Num;
1132 }
1133
1134 const BucketT *getInlineBuckets() const {
1135 assert(Small)((void)0);
1136 // Note that this cast does not violate aliasing rules as we assert that
1137 // the memory's dynamic type is the small, inline bucket buffer, and the
1138 // 'storage' is a POD containing a char buffer.
1139 return reinterpret_cast<const BucketT *>(&storage);
1140 }
1141
1142 BucketT *getInlineBuckets() {
1143 return const_cast<BucketT *>(
1144 const_cast<const SmallDenseMap *>(this)->getInlineBuckets());
1145 }
1146
1147 const LargeRep *getLargeRep() const {
1148 assert(!Small)((void)0);
1149 // Note, same rule about aliasing as with getInlineBuckets.
1150 return reinterpret_cast<const LargeRep *>(&storage);
1151 }
1152
1153 LargeRep *getLargeRep() {
1154 return const_cast<LargeRep *>(
1155 const_cast<const SmallDenseMap *>(this)->getLargeRep());
1156 }
1157
1158 const BucketT *getBuckets() const {
1159 return Small ? getInlineBuckets() : getLargeRep()->Buckets;
1160 }
1161
1162 BucketT *getBuckets() {
1163 return const_cast<BucketT *>(
1164 const_cast<const SmallDenseMap *>(this)->getBuckets());
1165 }
1166
1167 unsigned getNumBuckets() const {
1168 return Small ? InlineBuckets : getLargeRep()->NumBuckets;
1169 }
1170
1171 void deallocateBuckets() {
1172 if (Small)
1173 return;
1174
1175 deallocate_buffer(getLargeRep()->Buckets,
1176 sizeof(BucketT) * getLargeRep()->NumBuckets,
1177 alignof(BucketT));
1178 getLargeRep()->~LargeRep();
1179 }
1180
1181 LargeRep allocateBuckets(unsigned Num) {
1182 assert(Num > InlineBuckets && "Must allocate more buckets than are inline")((void)0);
1183 LargeRep Rep = {static_cast<BucketT *>(allocate_buffer(
1184 sizeof(BucketT) * Num, alignof(BucketT))),
1185 Num};
1186 return Rep;
1187 }
1188};
1189
1190template <typename KeyT, typename ValueT, typename KeyInfoT, typename Bucket,
1191 bool IsConst>
1192class DenseMapIterator : DebugEpochBase::HandleBase {
1193 friend class DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, true>;
1194 friend class DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, false>;
1195
1196public:
1197 using difference_type = ptrdiff_t;
1198 using value_type =
1199 typename std::conditional<IsConst, const Bucket, Bucket>::type;
1200 using pointer = value_type *;
1201 using reference = value_type &;
1202 using iterator_category = std::forward_iterator_tag;
1203
1204private:
1205 pointer Ptr = nullptr;
1206 pointer End = nullptr;
1207
1208public:
1209 DenseMapIterator() = default;
1210
1211 DenseMapIterator(pointer Pos, pointer E, const DebugEpochBase &Epoch,
1212 bool NoAdvance = false)
1213 : DebugEpochBase::HandleBase(&Epoch), Ptr(Pos), End(E) {
1214 assert(isHandleInSync() && "invalid construction!")((void)0);
1215
1216 if (NoAdvance) return;
1217 if (shouldReverseIterate<KeyT>()) {
1218 RetreatPastEmptyBuckets();
1219 return;
1220 }
1221 AdvancePastEmptyBuckets();
1222 }
1223
1224 // Converting ctor from non-const iterators to const iterators. SFINAE'd out
1225 // for const iterator destinations so it doesn't end up as a user defined copy
1226 // constructor.
1227 template <bool IsConstSrc,
1228 typename = std::enable_if_t<!IsConstSrc && IsConst>>
1229 DenseMapIterator(
1230 const DenseMapIterator<KeyT, ValueT, KeyInfoT, Bucket, IsConstSrc> &I)
1231 : DebugEpochBase::HandleBase(I), Ptr(I.Ptr), End(I.End) {}
1232
1233 reference operator*() const {
1234 assert(isHandleInSync() && "invalid iterator access!")((void)0);
1235 assert(Ptr != End && "dereferencing end() iterator")((void)0);
1236 if (shouldReverseIterate<KeyT>())
1237 return Ptr[-1];
1238 return *Ptr;
1239 }
1240 pointer operator->() const {
1241 assert(isHandleInSync() && "invalid iterator access!")((void)0);
1242 assert(Ptr != End && "dereferencing end() iterator")((void)0);
1243 if (shouldReverseIterate<KeyT>())
1244 return &(Ptr[-1]);
1245 return Ptr;
1246 }
1247
1248 friend bool operator==(const DenseMapIterator &LHS,
1249 const DenseMapIterator &RHS) {
1250 assert((!LHS.Ptr || LHS.isHandleInSync()) && "handle not in sync!")((void)0);
1251 assert((!RHS.Ptr || RHS.isHandleInSync()) && "handle not in sync!")((void)0);
1252 assert(LHS.getEpochAddress() == RHS.getEpochAddress() &&((void)0)
1253 "comparing incomparable iterators!")((void)0);
1254 return LHS.Ptr == RHS.Ptr;
12
Assuming 'LHS.Ptr' is not equal to 'RHS.Ptr'
13
Returning zero, which participates in a condition later
1255 }
1256
1257 friend bool operator!=(const DenseMapIterator &LHS,
1258 const DenseMapIterator &RHS) {
1259 return !(LHS == RHS);
11
Calling 'operator=='
14
Returning from 'operator=='
15
Returning the value 1, which participates in a condition later
1260 }
1261
1262 inline DenseMapIterator& operator++() { // Preincrement
1263 assert(isHandleInSync() && "invalid iterator access!")((void)0);
1264 assert(Ptr != End && "incrementing end() iterator")((void)0);
1265 if (shouldReverseIterate<KeyT>()) {
1266 --Ptr;
1267 RetreatPastEmptyBuckets();
1268 return *this;
1269 }
1270 ++Ptr;
1271 AdvancePastEmptyBuckets();
1272 return *this;
1273 }
1274 DenseMapIterator operator++(int) { // Postincrement
1275 assert(isHandleInSync() && "invalid iterator access!")((void)0);
1276 DenseMapIterator tmp = *this; ++*this; return tmp;
1277 }
1278
1279private:
1280 void AdvancePastEmptyBuckets() {
1281 assert(Ptr <= End)((void)0);
1282 const KeyT Empty = KeyInfoT::getEmptyKey();
1283 const KeyT Tombstone = KeyInfoT::getTombstoneKey();
1284
1285 while (Ptr != End && (KeyInfoT::isEqual(Ptr->getFirst(), Empty) ||
1286 KeyInfoT::isEqual(Ptr->getFirst(), Tombstone)))
1287 ++Ptr;
1288 }
1289
1290 void RetreatPastEmptyBuckets() {
1291 assert(Ptr >= End)((void)0);
1292 const KeyT Empty = KeyInfoT::getEmptyKey();
1293 const KeyT Tombstone = KeyInfoT::getTombstoneKey();
1294
1295 while (Ptr != End && (KeyInfoT::isEqual(Ptr[-1].getFirst(), Empty) ||
1296 KeyInfoT::isEqual(Ptr[-1].getFirst(), Tombstone)))
1297 --Ptr;
1298 }
1299};
1300
1301template <typename KeyT, typename ValueT, typename KeyInfoT>
1302inline size_t capacity_in_bytes(const DenseMap<KeyT, ValueT, KeyInfoT> &X) {
1303 return X.getMemorySize();
1304}
1305
1306} // end namespace llvm
1307
1308#endif // LLVM_ADT_DENSEMAP_H