Bug Summary

File:src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/CodeGen/RDFGraph.cpp
Warning:line 567, 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 RDFGraph.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/RDFGraph.cpp
1//===- RDFGraph.cpp -------------------------------------------------------===//
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// Target-independent, SSA-based data flow graph for register data flow (RDF).
10//
11#include "llvm/ADT/BitVector.h"
12#include "llvm/ADT/STLExtras.h"
13#include "llvm/ADT/SetVector.h"
14#include "llvm/CodeGen/MachineBasicBlock.h"
15#include "llvm/CodeGen/MachineDominanceFrontier.h"
16#include "llvm/CodeGen/MachineDominators.h"
17#include "llvm/CodeGen/MachineFunction.h"
18#include "llvm/CodeGen/MachineInstr.h"
19#include "llvm/CodeGen/MachineOperand.h"
20#include "llvm/CodeGen/MachineRegisterInfo.h"
21#include "llvm/CodeGen/RDFGraph.h"
22#include "llvm/CodeGen/RDFRegisters.h"
23#include "llvm/CodeGen/TargetInstrInfo.h"
24#include "llvm/CodeGen/TargetLowering.h"
25#include "llvm/CodeGen/TargetRegisterInfo.h"
26#include "llvm/CodeGen/TargetSubtargetInfo.h"
27#include "llvm/IR/Function.h"
28#include "llvm/MC/LaneBitmask.h"
29#include "llvm/MC/MCInstrDesc.h"
30#include "llvm/MC/MCRegisterInfo.h"
31#include "llvm/Support/Debug.h"
32#include "llvm/Support/ErrorHandling.h"
33#include "llvm/Support/raw_ostream.h"
34#include <algorithm>
35#include <cassert>
36#include <cstdint>
37#include <cstring>
38#include <iterator>
39#include <set>
40#include <utility>
41#include <vector>
42
43using namespace llvm;
44using namespace rdf;
45
46// Printing functions. Have them here first, so that the rest of the code
47// can use them.
48namespace llvm {
49namespace rdf {
50
51raw_ostream &operator<< (raw_ostream &OS, const PrintLaneMaskOpt &P) {
52 if (!P.Mask.all())
53 OS << ':' << PrintLaneMask(P.Mask);
54 return OS;
55}
56
57raw_ostream &operator<< (raw_ostream &OS, const Print<RegisterRef> &P) {
58 auto &TRI = P.G.getTRI();
59 if (P.Obj.Reg > 0 && P.Obj.Reg < TRI.getNumRegs())
60 OS << TRI.getName(P.Obj.Reg);
61 else
62 OS << '#' << P.Obj.Reg;
63 OS << PrintLaneMaskOpt(P.Obj.Mask);
64 return OS;
65}
66
67raw_ostream &operator<< (raw_ostream &OS, const Print<NodeId> &P) {
68 auto NA = P.G.addr<NodeBase*>(P.Obj);
69 uint16_t Attrs = NA.Addr->getAttrs();
70 uint16_t Kind = NodeAttrs::kind(Attrs);
71 uint16_t Flags = NodeAttrs::flags(Attrs);
72 switch (NodeAttrs::type(Attrs)) {
73 case NodeAttrs::Code:
74 switch (Kind) {
75 case NodeAttrs::Func: OS << 'f'; break;
76 case NodeAttrs::Block: OS << 'b'; break;
77 case NodeAttrs::Stmt: OS << 's'; break;
78 case NodeAttrs::Phi: OS << 'p'; break;
79 default: OS << "c?"; break;
80 }
81 break;
82 case NodeAttrs::Ref:
83 if (Flags & NodeAttrs::Undef)
84 OS << '/';
85 if (Flags & NodeAttrs::Dead)
86 OS << '\\';
87 if (Flags & NodeAttrs::Preserving)
88 OS << '+';
89 if (Flags & NodeAttrs::Clobbering)
90 OS << '~';
91 switch (Kind) {
92 case NodeAttrs::Use: OS << 'u'; break;
93 case NodeAttrs::Def: OS << 'd'; break;
94 case NodeAttrs::Block: OS << 'b'; break;
95 default: OS << "r?"; break;
96 }
97 break;
98 default:
99 OS << '?';
100 break;
101 }
102 OS << P.Obj;
103 if (Flags & NodeAttrs::Shadow)
104 OS << '"';
105 return OS;
106}
107
108static void printRefHeader(raw_ostream &OS, const NodeAddr<RefNode*> RA,
109 const DataFlowGraph &G) {
110 OS << Print<NodeId>(RA.Id, G) << '<'
111 << Print<RegisterRef>(RA.Addr->getRegRef(G), G) << '>';
112 if (RA.Addr->getFlags() & NodeAttrs::Fixed)
113 OS << '!';
114}
115
116raw_ostream &operator<< (raw_ostream &OS, const Print<NodeAddr<DefNode*>> &P) {
117 printRefHeader(OS, P.Obj, P.G);
118 OS << '(';
119 if (NodeId N = P.Obj.Addr->getReachingDef())
120 OS << Print<NodeId>(N, P.G);
121 OS << ',';
122 if (NodeId N = P.Obj.Addr->getReachedDef())
123 OS << Print<NodeId>(N, P.G);
124 OS << ',';
125 if (NodeId N = P.Obj.Addr->getReachedUse())
126 OS << Print<NodeId>(N, P.G);
127 OS << "):";
128 if (NodeId N = P.Obj.Addr->getSibling())
129 OS << Print<NodeId>(N, P.G);
130 return OS;
131}
132
133raw_ostream &operator<< (raw_ostream &OS, const Print<NodeAddr<UseNode*>> &P) {
134 printRefHeader(OS, P.Obj, P.G);
135 OS << '(';
136 if (NodeId N = P.Obj.Addr->getReachingDef())
137 OS << Print<NodeId>(N, P.G);
138 OS << "):";
139 if (NodeId N = P.Obj.Addr->getSibling())
140 OS << Print<NodeId>(N, P.G);
141 return OS;
142}
143
144raw_ostream &operator<< (raw_ostream &OS,
145 const Print<NodeAddr<PhiUseNode*>> &P) {
146 printRefHeader(OS, P.Obj, P.G);
147 OS << '(';
148 if (NodeId N = P.Obj.Addr->getReachingDef())
149 OS << Print<NodeId>(N, P.G);
150 OS << ',';
151 if (NodeId N = P.Obj.Addr->getPredecessor())
152 OS << Print<NodeId>(N, P.G);
153 OS << "):";
154 if (NodeId N = P.Obj.Addr->getSibling())
155 OS << Print<NodeId>(N, P.G);
156 return OS;
157}
158
159raw_ostream &operator<< (raw_ostream &OS, const Print<NodeAddr<RefNode*>> &P) {
160 switch (P.Obj.Addr->getKind()) {
161 case NodeAttrs::Def:
162 OS << PrintNode<DefNode*>(P.Obj, P.G);
163 break;
164 case NodeAttrs::Use:
165 if (P.Obj.Addr->getFlags() & NodeAttrs::PhiRef)
166 OS << PrintNode<PhiUseNode*>(P.Obj, P.G);
167 else
168 OS << PrintNode<UseNode*>(P.Obj, P.G);
169 break;
170 }
171 return OS;
172}
173
174raw_ostream &operator<< (raw_ostream &OS, const Print<NodeList> &P) {
175 unsigned N = P.Obj.size();
176 for (auto I : P.Obj) {
177 OS << Print<NodeId>(I.Id, P.G);
178 if (--N)
179 OS << ' ';
180 }
181 return OS;
182}
183
184raw_ostream &operator<< (raw_ostream &OS, const Print<NodeSet> &P) {
185 unsigned N = P.Obj.size();
186 for (auto I : P.Obj) {
187 OS << Print<NodeId>(I, P.G);
188 if (--N)
189 OS << ' ';
190 }
191 return OS;
192}
193
194namespace {
195
196 template <typename T>
197 struct PrintListV {
198 PrintListV(const NodeList &L, const DataFlowGraph &G) : List(L), G(G) {}
199
200 using Type = T;
201 const NodeList &List;
202 const DataFlowGraph &G;
203 };
204
205 template <typename T>
206 raw_ostream &operator<< (raw_ostream &OS, const PrintListV<T> &P) {
207 unsigned N = P.List.size();
208 for (NodeAddr<T> A : P.List) {
209 OS << PrintNode<T>(A, P.G);
210 if (--N)
211 OS << ", ";
212 }
213 return OS;
214 }
215
216} // end anonymous namespace
217
218raw_ostream &operator<< (raw_ostream &OS, const Print<NodeAddr<PhiNode*>> &P) {
219 OS << Print<NodeId>(P.Obj.Id, P.G) << ": phi ["
220 << PrintListV<RefNode*>(P.Obj.Addr->members(P.G), P.G) << ']';
221 return OS;
222}
223
224raw_ostream &operator<<(raw_ostream &OS, const Print<NodeAddr<StmtNode *>> &P) {
225 const MachineInstr &MI = *P.Obj.Addr->getCode();
226 unsigned Opc = MI.getOpcode();
227 OS << Print<NodeId>(P.Obj.Id, P.G) << ": " << P.G.getTII().getName(Opc);
228 // Print the target for calls and branches (for readability).
229 if (MI.isCall() || MI.isBranch()) {
230 MachineInstr::const_mop_iterator T =
231 llvm::find_if(MI.operands(),
232 [] (const MachineOperand &Op) -> bool {
233 return Op.isMBB() || Op.isGlobal() || Op.isSymbol();
234 });
235 if (T != MI.operands_end()) {
236 OS << ' ';
237 if (T->isMBB())
238 OS << printMBBReference(*T->getMBB());
239 else if (T->isGlobal())
240 OS << T->getGlobal()->getName();
241 else if (T->isSymbol())
242 OS << T->getSymbolName();
243 }
244 }
245 OS << " [" << PrintListV<RefNode*>(P.Obj.Addr->members(P.G), P.G) << ']';
246 return OS;
247}
248
249raw_ostream &operator<< (raw_ostream &OS,
250 const Print<NodeAddr<InstrNode*>> &P) {
251 switch (P.Obj.Addr->getKind()) {
252 case NodeAttrs::Phi:
253 OS << PrintNode<PhiNode*>(P.Obj, P.G);
254 break;
255 case NodeAttrs::Stmt:
256 OS << PrintNode<StmtNode*>(P.Obj, P.G);
257 break;
258 default:
259 OS << "instr? " << Print<NodeId>(P.Obj.Id, P.G);
260 break;
261 }
262 return OS;
263}
264
265raw_ostream &operator<< (raw_ostream &OS,
266 const Print<NodeAddr<BlockNode*>> &P) {
267 MachineBasicBlock *BB = P.Obj.Addr->getCode();
268 unsigned NP = BB->pred_size();
269 std::vector<int> Ns;
270 auto PrintBBs = [&OS] (std::vector<int> Ns) -> void {
271 unsigned N = Ns.size();
272 for (int I : Ns) {
273 OS << "%bb." << I;
274 if (--N)
275 OS << ", ";
276 }
277 };
278
279 OS << Print<NodeId>(P.Obj.Id, P.G) << ": --- " << printMBBReference(*BB)
280 << " --- preds(" << NP << "): ";
281 for (MachineBasicBlock *B : BB->predecessors())
282 Ns.push_back(B->getNumber());
283 PrintBBs(Ns);
284
285 unsigned NS = BB->succ_size();
286 OS << " succs(" << NS << "): ";
287 Ns.clear();
288 for (MachineBasicBlock *B : BB->successors())
289 Ns.push_back(B->getNumber());
290 PrintBBs(Ns);
291 OS << '\n';
292
293 for (auto I : P.Obj.Addr->members(P.G))
294 OS << PrintNode<InstrNode*>(I, P.G) << '\n';
295 return OS;
296}
297
298raw_ostream &operator<<(raw_ostream &OS, const Print<NodeAddr<FuncNode *>> &P) {
299 OS << "DFG dump:[\n" << Print<NodeId>(P.Obj.Id, P.G) << ": Function: "
300 << P.Obj.Addr->getCode()->getName() << '\n';
301 for (auto I : P.Obj.Addr->members(P.G))
302 OS << PrintNode<BlockNode*>(I, P.G) << '\n';
303 OS << "]\n";
304 return OS;
305}
306
307raw_ostream &operator<< (raw_ostream &OS, const Print<RegisterSet> &P) {
308 OS << '{';
309 for (auto I : P.Obj)
310 OS << ' ' << Print<RegisterRef>(I, P.G);
311 OS << " }";
312 return OS;
313}
314
315raw_ostream &operator<< (raw_ostream &OS, const Print<RegisterAggr> &P) {
316 P.Obj.print(OS);
317 return OS;
318}
319
320raw_ostream &operator<< (raw_ostream &OS,
321 const Print<DataFlowGraph::DefStack> &P) {
322 for (auto I = P.Obj.top(), E = P.Obj.bottom(); I != E; ) {
323 OS << Print<NodeId>(I->Id, P.G)
324 << '<' << Print<RegisterRef>(I->Addr->getRegRef(P.G), P.G) << '>';
325 I.down();
326 if (I != E)
327 OS << ' ';
328 }
329 return OS;
330}
331
332} // end namespace rdf
333} // end namespace llvm
334
335// Node allocation functions.
336//
337// Node allocator is like a slab memory allocator: it allocates blocks of
338// memory in sizes that are multiples of the size of a node. Each block has
339// the same size. Nodes are allocated from the currently active block, and
340// when it becomes full, a new one is created.
341// There is a mapping scheme between node id and its location in a block,
342// and within that block is described in the header file.
343//
344void NodeAllocator::startNewBlock() {
345 void *T = MemPool.Allocate(NodesPerBlock*NodeMemSize, NodeMemSize);
346 char *P = static_cast<char*>(T);
347 Blocks.push_back(P);
348 // Check if the block index is still within the allowed range, i.e. less
349 // than 2^N, where N is the number of bits in NodeId for the block index.
350 // BitsPerIndex is the number of bits per node index.
351 assert((Blocks.size() < ((size_t)1 << (8*sizeof(NodeId)-BitsPerIndex))) &&((void)0)
352 "Out of bits for block index")((void)0);
353 ActiveEnd = P;
354}
355
356bool NodeAllocator::needNewBlock() {
357 if (Blocks.empty())
358 return true;
359
360 char *ActiveBegin = Blocks.back();
361 uint32_t Index = (ActiveEnd-ActiveBegin)/NodeMemSize;
362 return Index >= NodesPerBlock;
363}
364
365NodeAddr<NodeBase*> NodeAllocator::New() {
366 if (needNewBlock())
367 startNewBlock();
368
369 uint32_t ActiveB = Blocks.size()-1;
370 uint32_t Index = (ActiveEnd - Blocks[ActiveB])/NodeMemSize;
371 NodeAddr<NodeBase*> NA = { reinterpret_cast<NodeBase*>(ActiveEnd),
372 makeId(ActiveB, Index) };
373 ActiveEnd += NodeMemSize;
374 return NA;
375}
376
377NodeId NodeAllocator::id(const NodeBase *P) const {
378 uintptr_t A = reinterpret_cast<uintptr_t>(P);
379 for (unsigned i = 0, n = Blocks.size(); i != n; ++i) {
380 uintptr_t B = reinterpret_cast<uintptr_t>(Blocks[i]);
381 if (A < B || A >= B + NodesPerBlock*NodeMemSize)
382 continue;
383 uint32_t Idx = (A-B)/NodeMemSize;
384 return makeId(i, Idx);
385 }
386 llvm_unreachable("Invalid node address")__builtin_unreachable();
387}
388
389void NodeAllocator::clear() {
390 MemPool.Reset();
391 Blocks.clear();
392 ActiveEnd = nullptr;
393}
394
395// Insert node NA after "this" in the circular chain.
396void NodeBase::append(NodeAddr<NodeBase*> NA) {
397 NodeId Nx = Next;
398 // If NA is already "next", do nothing.
399 if (Next != NA.Id) {
400 Next = NA.Id;
401 NA.Addr->Next = Nx;
402 }
403}
404
405// Fundamental node manipulator functions.
406
407// Obtain the register reference from a reference node.
408RegisterRef RefNode::getRegRef(const DataFlowGraph &G) const {
409 assert(NodeAttrs::type(Attrs) == NodeAttrs::Ref)((void)0);
410 if (NodeAttrs::flags(Attrs) & NodeAttrs::PhiRef)
411 return G.unpack(Ref.PR);
412 assert(Ref.Op != nullptr)((void)0);
413 return G.makeRegRef(*Ref.Op);
414}
415
416// Set the register reference in the reference node directly (for references
417// in phi nodes).
418void RefNode::setRegRef(RegisterRef RR, DataFlowGraph &G) {
419 assert(NodeAttrs::type(Attrs) == NodeAttrs::Ref)((void)0);
420 assert(NodeAttrs::flags(Attrs) & NodeAttrs::PhiRef)((void)0);
421 Ref.PR = G.pack(RR);
422}
423
424// Set the register reference in the reference node based on a machine
425// operand (for references in statement nodes).
426void RefNode::setRegRef(MachineOperand *Op, DataFlowGraph &G) {
427 assert(NodeAttrs::type(Attrs) == NodeAttrs::Ref)((void)0);
428 assert(!(NodeAttrs::flags(Attrs) & NodeAttrs::PhiRef))((void)0);
429 (void)G;
430 Ref.Op = Op;
431}
432
433// Get the owner of a given reference node.
434NodeAddr<NodeBase*> RefNode::getOwner(const DataFlowGraph &G) {
435 NodeAddr<NodeBase*> NA = G.addr<NodeBase*>(getNext());
436
437 while (NA.Addr != this) {
438 if (NA.Addr->getType() == NodeAttrs::Code)
439 return NA;
440 NA = G.addr<NodeBase*>(NA.Addr->getNext());
441 }
442 llvm_unreachable("No owner in circular list")__builtin_unreachable();
443}
444
445// Connect the def node to the reaching def node.
446void DefNode::linkToDef(NodeId Self, NodeAddr<DefNode*> DA) {
447 Ref.RD = DA.Id;
448 Ref.Sib = DA.Addr->getReachedDef();
449 DA.Addr->setReachedDef(Self);
450}
451
452// Connect the use node to the reaching def node.
453void UseNode::linkToDef(NodeId Self, NodeAddr<DefNode*> DA) {
454 Ref.RD = DA.Id;
455 Ref.Sib = DA.Addr->getReachedUse();
456 DA.Addr->setReachedUse(Self);
457}
458
459// Get the first member of the code node.
460NodeAddr<NodeBase*> CodeNode::getFirstMember(const DataFlowGraph &G) const {
461 if (Code.FirstM == 0)
462 return NodeAddr<NodeBase*>();
463 return G.addr<NodeBase*>(Code.FirstM);
464}
465
466// Get the last member of the code node.
467NodeAddr<NodeBase*> CodeNode::getLastMember(const DataFlowGraph &G) const {
468 if (Code.LastM == 0)
469 return NodeAddr<NodeBase*>();
470 return G.addr<NodeBase*>(Code.LastM);
471}
472
473// Add node NA at the end of the member list of the given code node.
474void CodeNode::addMember(NodeAddr<NodeBase*> NA, const DataFlowGraph &G) {
475 NodeAddr<NodeBase*> ML = getLastMember(G);
476 if (ML.Id != 0) {
477 ML.Addr->append(NA);
478 } else {
479 Code.FirstM = NA.Id;
480 NodeId Self = G.id(this);
481 NA.Addr->setNext(Self);
482 }
483 Code.LastM = NA.Id;
484}
485
486// Add node NA after member node MA in the given code node.
487void CodeNode::addMemberAfter(NodeAddr<NodeBase*> MA, NodeAddr<NodeBase*> NA,
488 const DataFlowGraph &G) {
489 MA.Addr->append(NA);
490 if (Code.LastM == MA.Id)
491 Code.LastM = NA.Id;
492}
493
494// Remove member node NA from the given code node.
495void CodeNode::removeMember(NodeAddr<NodeBase*> NA, const DataFlowGraph &G) {
496 NodeAddr<NodeBase*> MA = getFirstMember(G);
497 assert(MA.Id != 0)((void)0);
498
499 // Special handling if the member to remove is the first member.
500 if (MA.Id == NA.Id) {
501 if (Code.LastM == MA.Id) {
502 // If it is the only member, set both first and last to 0.
503 Code.FirstM = Code.LastM = 0;
504 } else {
505 // Otherwise, advance the first member.
506 Code.FirstM = MA.Addr->getNext();
507 }
508 return;
509 }
510
511 while (MA.Addr != this) {
512 NodeId MX = MA.Addr->getNext();
513 if (MX == NA.Id) {
514 MA.Addr->setNext(NA.Addr->getNext());
515 // If the member to remove happens to be the last one, update the
516 // LastM indicator.
517 if (Code.LastM == NA.Id)
518 Code.LastM = MA.Id;
519 return;
520 }
521 MA = G.addr<NodeBase*>(MX);
522 }
523 llvm_unreachable("No such member")__builtin_unreachable();
524}
525
526// Return the list of all members of the code node.
527NodeList CodeNode::members(const DataFlowGraph &G) const {
528 static auto True = [] (NodeAddr<NodeBase*>) -> bool { return true; };
529 return members_if(True, G);
530}
531
532// Return the owner of the given instr node.
533NodeAddr<NodeBase*> InstrNode::getOwner(const DataFlowGraph &G) {
534 NodeAddr<NodeBase*> NA = G.addr<NodeBase*>(getNext());
535
536 while (NA.Addr != this) {
537 assert(NA.Addr->getType() == NodeAttrs::Code)((void)0);
538 if (NA.Addr->getKind() == NodeAttrs::Block)
539 return NA;
540 NA = G.addr<NodeBase*>(NA.Addr->getNext());
541 }
542 llvm_unreachable("No owner in circular list")__builtin_unreachable();
543}
544
545// Add the phi node PA to the given block node.
546void BlockNode::addPhi(NodeAddr<PhiNode*> PA, const DataFlowGraph &G) {
547 NodeAddr<NodeBase*> M = getFirstMember(G);
548 if (M.Id
13.1
Field 'Id' is not equal to 0
 == 0) {
14
←
Taking false branch
→
549 addMember(PA, G);
550 return;
551 }
552
553 assert(M.Addr->getType() == NodeAttrs::Code)((void)0);
554 if (M.Addr->getKind() == NodeAttrs::Stmt) {
15
←
Assuming the condition is false
→
16
←
Taking false branch
→
555 // If the first member of the block is a statement, insert the phi as
556 // the first member.
557 Code.FirstM = PA.Id;
558 PA.Addr->setNext(M.Id);
559 } else {
560 // If the first member is a phi, find the last phi, and append PA to it.
561 assert(M.Addr->getKind() == NodeAttrs::Phi)((void)0);
562 NodeAddr<NodeBase*> MN = M;
563 do {
564 M = MN;
565 MN = G.addr<NodeBase*>(M.Addr->getNext());
17
←
Null pointer value stored to 'MN.Addr'
→
566 assert(MN.Addr->getType() == NodeAttrs::Code)((void)0);
567 } while (MN.Addr->getKind() == NodeAttrs::Phi);
18
←
Called C++ object pointer is null
568
569 // M is the last phi.
570 addMemberAfter(M, PA, G);
571 }
572}
573
574// Find the block node corresponding to the machine basic block BB in the
575// given func node.
576NodeAddr<BlockNode*> FuncNode::findBlock(const MachineBasicBlock *BB,
577 const DataFlowGraph &G) const {
578 auto EqBB = [BB] (NodeAddr<NodeBase*> NA) -> bool {
579 return NodeAddr<BlockNode*>(NA).Addr->getCode() == BB;
580 };
581 NodeList Ms = members_if(EqBB, G);
582 if (!Ms.empty())
583 return Ms[0];
584 return NodeAddr<BlockNode*>();
585}
586
587// Get the block node for the entry block in the given function.
588NodeAddr<BlockNode*> FuncNode::getEntryBlock(const DataFlowGraph &G) {
589 MachineBasicBlock *EntryB = &getCode()->front();
590 return findBlock(EntryB, G);
591}
592
593// Target operand information.
594//
595
596// For a given instruction, check if there are any bits of RR that can remain
597// unchanged across this def.
598bool TargetOperandInfo::isPreserving(const MachineInstr &In, unsigned OpNum)
599 const {
600 return TII.isPredicated(In);
601}
602
603// Check if the definition of RR produces an unspecified value.
604bool TargetOperandInfo::isClobbering(const MachineInstr &In, unsigned OpNum)
605 const {
606 const MachineOperand &Op = In.getOperand(OpNum);
607 if (Op.isRegMask())
608 return true;
609 assert(Op.isReg())((void)0);
610 if (In.isCall())
611 if (Op.isDef() && Op.isDead())
612 return true;
613 return false;
614}
615
616// Check if the given instruction specifically requires
617bool TargetOperandInfo::isFixedReg(const MachineInstr &In, unsigned OpNum)
618 const {
619 if (In.isCall() || In.isReturn() || In.isInlineAsm())
620 return true;
621 // Check for a tail call.
622 if (In.isBranch())
623 for (const MachineOperand &O : In.operands())
624 if (O.isGlobal() || O.isSymbol())
625 return true;
626
627 const MCInstrDesc &D = In.getDesc();
628 if (!D.getImplicitDefs() && !D.getImplicitUses())
629 return false;
630 const MachineOperand &Op = In.getOperand(OpNum);
631 // If there is a sub-register, treat the operand as non-fixed. Currently,
632 // fixed registers are those that are listed in the descriptor as implicit
633 // uses or defs, and those lists do not allow sub-registers.
634 if (Op.getSubReg() != 0)
635 return false;
636 Register Reg = Op.getReg();
637 const MCPhysReg *ImpR = Op.isDef() ? D.getImplicitDefs()
638 : D.getImplicitUses();
639 if (!ImpR)
640 return false;
641 while (*ImpR)
642 if (*ImpR++ == Reg)
643 return true;
644 return false;
645}
646
647//
648// The data flow graph construction.
649//
650
651DataFlowGraph::DataFlowGraph(MachineFunction &mf, const TargetInstrInfo &tii,
652 const TargetRegisterInfo &tri, const MachineDominatorTree &mdt,
653 const MachineDominanceFrontier &mdf, const TargetOperandInfo &toi)
654 : MF(mf), TII(tii), TRI(tri), PRI(tri, mf), MDT(mdt), MDF(mdf), TOI(toi),
655 LiveIns(PRI) {
656}
657
658// The implementation of the definition stack.
659// Each register reference has its own definition stack. In particular,
660// for a register references "Reg" and "Reg:subreg" will each have their
661// own definition stacks.
662
663// Construct a stack iterator.
664DataFlowGraph::DefStack::Iterator::Iterator(const DataFlowGraph::DefStack &S,
665 bool Top) : DS(S) {
666 if (!Top) {
667 // Initialize to bottom.
668 Pos = 0;
669 return;
670 }
671 // Initialize to the top, i.e. top-most non-delimiter (or 0, if empty).
672 Pos = DS.Stack.size();
673 while (Pos > 0 && DS.isDelimiter(DS.Stack[Pos-1]))
674 Pos--;
675}
676
677// Return the size of the stack, including block delimiters.
678unsigned DataFlowGraph::DefStack::size() const {
679 unsigned S = 0;
680 for (auto I = top(), E = bottom(); I != E; I.down())
681 S++;
682 return S;
683}
684
685// Remove the top entry from the stack. Remove all intervening delimiters
686// so that after this, the stack is either empty, or the top of the stack
687// is a non-delimiter.
688void DataFlowGraph::DefStack::pop() {
689 assert(!empty())((void)0);
690 unsigned P = nextDown(Stack.size());
691 Stack.resize(P);
692}
693
694// Push a delimiter for block node N on the stack.
695void DataFlowGraph::DefStack::start_block(NodeId N) {
696 assert(N != 0)((void)0);
697 Stack.push_back(NodeAddr<DefNode*>(nullptr, N));
698}
699
700// Remove all nodes from the top of the stack, until the delimited for
701// block node N is encountered. Remove the delimiter as well. In effect,
702// this will remove from the stack all definitions from block N.
703void DataFlowGraph::DefStack::clear_block(NodeId N) {
704 assert(N != 0)((void)0);
705 unsigned P = Stack.size();
706 while (P > 0) {
707 bool Found = isDelimiter(Stack[P-1], N);
708 P--;
709 if (Found)
710 break;
711 }
712 // This will also remove the delimiter, if found.
713 Stack.resize(P);
714}
715
716// Move the stack iterator up by one.
717unsigned DataFlowGraph::DefStack::nextUp(unsigned P) const {
718 // Get the next valid position after P (skipping all delimiters).
719 // The input position P does not have to point to a non-delimiter.
720 unsigned SS = Stack.size();
721 bool IsDelim;
722 assert(P < SS)((void)0);
723 do {
724 P++;
725 IsDelim = isDelimiter(Stack[P-1]);
726 } while (P < SS && IsDelim);
727 assert(!IsDelim)((void)0);
728 return P;
729}
730
731// Move the stack iterator down by one.
732unsigned DataFlowGraph::DefStack::nextDown(unsigned P) const {
733 // Get the preceding valid position before P (skipping all delimiters).
734 // The input position P does not have to point to a non-delimiter.
735 assert(P > 0 && P <= Stack.size())((void)0);
736 bool IsDelim = isDelimiter(Stack[P-1]);
737 do {
738 if (--P == 0)
739 break;
740 IsDelim = isDelimiter(Stack[P-1]);
741 } while (P > 0 && IsDelim);
742 assert(!IsDelim)((void)0);
743 return P;
744}
745
746// Register information.
747
748RegisterSet DataFlowGraph::getLandingPadLiveIns() const {
749 RegisterSet LR;
750 const Function &F = MF.getFunction();
751 const Constant *PF = F.hasPersonalityFn() ? F.getPersonalityFn()
752 : nullptr;
753 const TargetLowering &TLI = *MF.getSubtarget().getTargetLowering();
754 if (RegisterId R = TLI.getExceptionPointerRegister(PF))
755 LR.insert(RegisterRef(R));
756 if (!isFuncletEHPersonality(classifyEHPersonality(PF))) {
757 if (RegisterId R = TLI.getExceptionSelectorRegister(PF))
758 LR.insert(RegisterRef(R));
759 }
760 return LR;
761}
762
763// Node management functions.
764
765// Get the pointer to the node with the id N.
766NodeBase *DataFlowGraph::ptr(NodeId N) const {
767 if (N == 0)
768 return nullptr;
769 return Memory.ptr(N);
770}
771
772// Get the id of the node at the address P.
773NodeId DataFlowGraph::id(const NodeBase *P) const {
774 if (P == nullptr)
775 return 0;
776 return Memory.id(P);
777}
778
779// Allocate a new node and set the attributes to Attrs.
780NodeAddr<NodeBase*> DataFlowGraph::newNode(uint16_t Attrs) {
781 NodeAddr<NodeBase*> P = Memory.New();
782 P.Addr->init();
783 P.Addr->setAttrs(Attrs);
784 return P;
785}
786
787// Make a copy of the given node B, except for the data-flow links, which
788// are set to 0.
789NodeAddr<NodeBase*> DataFlowGraph::cloneNode(const NodeAddr<NodeBase*> B) {
790 NodeAddr<NodeBase*> NA = newNode(0);
791 memcpy(NA.Addr, B.Addr, sizeof(NodeBase));
792 // Ref nodes need to have the data-flow links reset.
793 if (NA.Addr->getType() == NodeAttrs::Ref) {
794 NodeAddr<RefNode*> RA = NA;
795 RA.Addr->setReachingDef(0);
796 RA.Addr->setSibling(0);
797 if (NA.Addr->getKind() == NodeAttrs::Def) {
798 NodeAddr<DefNode*> DA = NA;
799 DA.Addr->setReachedDef(0);
800 DA.Addr->setReachedUse(0);
801 }
802 }
803 return NA;
804}
805
806// Allocation routines for specific node types/kinds.
807
808NodeAddr<UseNode*> DataFlowGraph::newUse(NodeAddr<InstrNode*> Owner,
809 MachineOperand &Op, uint16_t Flags) {
810 NodeAddr<UseNode*> UA = newNode(NodeAttrs::Ref | NodeAttrs::Use | Flags);
811 UA.Addr->setRegRef(&Op, *this);
812 return UA;
813}
814
815NodeAddr<PhiUseNode*> DataFlowGraph::newPhiUse(NodeAddr<PhiNode*> Owner,
816 RegisterRef RR, NodeAddr<BlockNode*> PredB, uint16_t Flags) {
817 NodeAddr<PhiUseNode*> PUA = newNode(NodeAttrs::Ref | NodeAttrs::Use | Flags);
818 assert(Flags & NodeAttrs::PhiRef)((void)0);
819 PUA.Addr->setRegRef(RR, *this);
820 PUA.Addr->setPredecessor(PredB.Id);
821 return PUA;
822}
823
824NodeAddr<DefNode*> DataFlowGraph::newDef(NodeAddr<InstrNode*> Owner,
825 MachineOperand &Op, uint16_t Flags) {
826 NodeAddr<DefNode*> DA = newNode(NodeAttrs::Ref | NodeAttrs::Def | Flags);
827 DA.Addr->setRegRef(&Op, *this);
828 return DA;
829}
830
831NodeAddr<DefNode*> DataFlowGraph::newDef(NodeAddr<InstrNode*> Owner,
832 RegisterRef RR, uint16_t Flags) {
833 NodeAddr<DefNode*> DA = newNode(NodeAttrs::Ref | NodeAttrs::Def | Flags);
834 assert(Flags & NodeAttrs::PhiRef)((void)0);
835 DA.Addr->setRegRef(RR, *this);
836 return DA;
837}
838
839NodeAddr<PhiNode*> DataFlowGraph::newPhi(NodeAddr<BlockNode*> Owner) {
840 NodeAddr<PhiNode*> PA = newNode(NodeAttrs::Code | NodeAttrs::Phi);
841 Owner.Addr->addPhi(PA, *this);
13
←
Calling 'BlockNode::addPhi'
→
842 return PA;
843}
844
845NodeAddr<StmtNode*> DataFlowGraph::newStmt(NodeAddr<BlockNode*> Owner,
846 MachineInstr *MI) {
847 NodeAddr<StmtNode*> SA = newNode(NodeAttrs::Code | NodeAttrs::Stmt);
848 SA.Addr->setCode(MI);
849 Owner.Addr->addMember(SA, *this);
850 return SA;
851}
852
853NodeAddr<BlockNode*> DataFlowGraph::newBlock(NodeAddr<FuncNode*> Owner,
854 MachineBasicBlock *BB) {
855 NodeAddr<BlockNode*> BA = newNode(NodeAttrs::Code | NodeAttrs::Block);
856 BA.Addr->setCode(BB);
857 Owner.Addr->addMember(BA, *this);
858 return BA;
859}
860
861NodeAddr<FuncNode*> DataFlowGraph::newFunc(MachineFunction *MF) {
862 NodeAddr<FuncNode*> FA = newNode(NodeAttrs::Code | NodeAttrs::Func);
863 FA.Addr->setCode(MF);
864 return FA;
865}
866
867// Build the data flow graph.
868void DataFlowGraph::build(unsigned Options) {
869 reset();
870 Func = newFunc(&MF);
871
872 if (MF.empty())
1
Assuming the condition is false
→
2
←
Taking false branch
→
873 return;
874
875 for (MachineBasicBlock &B : MF) {
876 NodeAddr<BlockNode*> BA = newBlock(Func, &B);
877 BlockNodes.insert(std::make_pair(&B, BA));
878 for (MachineInstr &I : B) {
879 if (I.isDebugInstr())
880 continue;
881 buildStmt(BA, I);
882 }
883 }
884
885 NodeAddr<BlockNode*> EA = Func.Addr->getEntryBlock(*this);
886 NodeList Blocks = Func.Addr->members(*this);
887
888 // Collect information about block references.
889 RegisterSet AllRefs;
890 for (NodeAddr<BlockNode*> BA : Blocks)
3
←
Assuming '__begin1' is equal to '__end1'
→
891 for (NodeAddr<InstrNode*> IA : BA.Addr->members(*this))
892 for (NodeAddr<RefNode*> RA : IA.Addr->members(*this))
893 AllRefs.insert(RA.Addr->getRegRef(*this));
894
895 // Collect function live-ins and entry block live-ins.
896 MachineRegisterInfo &MRI = MF.getRegInfo();
897 MachineBasicBlock &EntryB = *EA.Addr->getCode();
898 assert(EntryB.pred_empty() && "Function entry block has predecessors")((void)0);
899 for (std::pair<unsigned,unsigned> P : MRI.liveins())
4
←
Assuming '__begin1' is equal to '__end1'
→
900 LiveIns.insert(RegisterRef(P.first));
901 if (MRI.tracksLiveness()) {
5
←
Taking false branch
→
902 for (auto I : EntryB.liveins())
903 LiveIns.insert(RegisterRef(I.PhysReg, I.LaneMask));
904 }
905
906 // Add function-entry phi nodes for the live-in registers.
907 //for (std::pair<RegisterId,LaneBitmask> P : LiveIns) {
908 for (auto I = LiveIns.rr_begin(), E = LiveIns.rr_end(); I != E; ++I) {
6
←
Loop condition is false. Execution continues on line 921
→
909 RegisterRef RR = *I;
910 NodeAddr<PhiNode*> PA = newPhi(EA);
911 uint16_t PhiFlags = NodeAttrs::PhiRef | NodeAttrs::Preserving;
912 NodeAddr<DefNode*> DA = newDef(PA, RR, PhiFlags);
913 PA.Addr->addMember(DA, *this);
914 }
915
916 // Add phis for landing pads.
917 // Landing pads, unlike usual backs blocks, are not entered through
918 // branches in the program, or fall-throughs from other blocks. They
919 // are entered from the exception handling runtime and target's ABI
920 // may define certain registers as defined on entry to such a block.
921 RegisterSet EHRegs = getLandingPadLiveIns();
922 if (!EHRegs.empty()) {
7
←
Assuming the condition is true
→
8
←
Taking true branch
→
923 for (NodeAddr<BlockNode*> BA : Blocks) {
9
←
Assuming '__begin2' is not equal to '__end2'
→
924 const MachineBasicBlock &B = *BA.Addr->getCode();
925 if (!B.isEHPad())
10
←
Assuming the condition is false
→
11
←
Taking false branch
→
926 continue;
927
928 // Prepare a list of NodeIds of the block's predecessors.
929 NodeList Preds;
930 for (MachineBasicBlock *PB : B.predecessors())
931 Preds.push_back(findBlock(PB));
932
933 // Build phi nodes for each live-in.
934 for (RegisterRef RR : EHRegs) {
935 NodeAddr<PhiNode*> PA = newPhi(BA);
12
←
Calling 'DataFlowGraph::newPhi'
→
936 uint16_t PhiFlags = NodeAttrs::PhiRef | NodeAttrs::Preserving;
937 // Add def:
938 NodeAddr<DefNode*> DA = newDef(PA, RR, PhiFlags);
939 PA.Addr->addMember(DA, *this);
940 // Add uses (no reaching defs for phi uses):
941 for (NodeAddr<BlockNode*> PBA : Preds) {
942 NodeAddr<PhiUseNode*> PUA = newPhiUse(PA, RR, PBA);
943 PA.Addr->addMember(PUA, *this);
944 }
945 }
946 }
947 }
948
949 // Build a map "PhiM" which will contain, for each block, the set
950 // of references that will require phi definitions in that block.
951 BlockRefsMap PhiM;
952 for (NodeAddr<BlockNode*> BA : Blocks)
953 recordDefsForDF(PhiM, BA);
954 for (NodeAddr<BlockNode*> BA : Blocks)
955 buildPhis(PhiM, AllRefs, BA);
956
957 // Link all the refs. This will recursively traverse the dominator tree.
958 DefStackMap DM;
959 linkBlockRefs(DM, EA);
960
961 // Finally, remove all unused phi nodes.
962 if (!(Options & BuildOptions::KeepDeadPhis))
963 removeUnusedPhis();
964}
965
966RegisterRef DataFlowGraph::makeRegRef(unsigned Reg, unsigned Sub) const {
967 assert(PhysicalRegisterInfo::isRegMaskId(Reg) ||((void)0)
968 Register::isPhysicalRegister(Reg))((void)0);
969 assert(Reg != 0)((void)0);
970 if (Sub != 0)
971 Reg = TRI.getSubReg(Reg, Sub);
972 return RegisterRef(Reg);
973}
974
975RegisterRef DataFlowGraph::makeRegRef(const MachineOperand &Op) const {
976 assert(Op.isReg() || Op.isRegMask())((void)0);
977 if (Op.isReg())
978 return makeRegRef(Op.getReg(), Op.getSubReg());
979 return RegisterRef(PRI.getRegMaskId(Op.getRegMask()), LaneBitmask::getAll());
980}
981
982RegisterRef DataFlowGraph::restrictRef(RegisterRef AR, RegisterRef BR) const {
983 if (AR.Reg == BR.Reg) {
984 LaneBitmask M = AR.Mask & BR.Mask;
985 return M.any() ? RegisterRef(AR.Reg, M) : RegisterRef();
986 }
987 // This isn't strictly correct, because the overlap may happen in the
988 // part masked out.
989 if (PRI.alias(AR, BR))
990 return AR;
991 return RegisterRef();
992}
993
994// For each stack in the map DefM, push the delimiter for block B on it.
995void DataFlowGraph::markBlock(NodeId B, DefStackMap &DefM) {
996 // Push block delimiters.
997 for (auto &P : DefM)
998 P.second.start_block(B);
999}
1000
1001// Remove all definitions coming from block B from each stack in DefM.
1002void DataFlowGraph::releaseBlock(NodeId B, DefStackMap &DefM) {
1003 // Pop all defs from this block from the definition stack. Defs that were
1004 // added to the map during the traversal of instructions will not have a
1005 // delimiter, but for those, the whole stack will be emptied.
1006 for (auto &P : DefM)
1007 P.second.clear_block(B);
1008
1009 // Finally, remove empty stacks from the map.
1010 for (auto I = DefM.begin(), E = DefM.end(), NextI = I; I != E; I = NextI) {
1011 NextI = std::next(I);
1012 // This preserves the validity of iterators other than I.
1013 if (I->second.empty())
1014 DefM.erase(I);
1015 }
1016}
1017
1018// Push all definitions from the instruction node IA to an appropriate
1019// stack in DefM.
1020void DataFlowGraph::pushAllDefs(NodeAddr<InstrNode*> IA, DefStackMap &DefM) {
1021 pushClobbers(IA, DefM);
1022 pushDefs(IA, DefM);
1023}
1024
1025// Push all definitions from the instruction node IA to an appropriate
1026// stack in DefM.
1027void DataFlowGraph::pushClobbers(NodeAddr<InstrNode*> IA, DefStackMap &DefM) {
1028 NodeSet Visited;
1029 std::set<RegisterId> Defined;
1030
1031 // The important objectives of this function are:
1032 // - to be able to handle instructions both while the graph is being
1033 // constructed, and after the graph has been constructed, and
1034 // - maintain proper ordering of definitions on the stack for each
1035 // register reference:
1036 // - if there are two or more related defs in IA (i.e. coming from
1037 // the same machine operand), then only push one def on the stack,
1038 // - if there are multiple unrelated defs of non-overlapping
1039 // subregisters of S, then the stack for S will have both (in an
1040 // unspecified order), but the order does not matter from the data-
1041 // -flow perspective.
1042
1043 for (NodeAddr<DefNode*> DA : IA.Addr->members_if(IsDef, *this)) {
1044 if (Visited.count(DA.Id))
1045 continue;
1046 if (!(DA.Addr->getFlags() & NodeAttrs::Clobbering))
1047 continue;
1048
1049 NodeList Rel = getRelatedRefs(IA, DA);
1050 NodeAddr<DefNode*> PDA = Rel.front();
1051 RegisterRef RR = PDA.Addr->getRegRef(*this);
1052
1053 // Push the definition on the stack for the register and all aliases.
1054 // The def stack traversal in linkNodeUp will check the exact aliasing.
1055 DefM[RR.Reg].push(DA);
1056 Defined.insert(RR.Reg);
1057 for (RegisterId A : PRI.getAliasSet(RR.Reg)) {
1058 // Check that we don't push the same def twice.
1059 assert(A != RR.Reg)((void)0);
1060 if (!Defined.count(A))
1061 DefM[A].push(DA);
1062 }
1063 // Mark all the related defs as visited.
1064 for (NodeAddr<NodeBase*> T : Rel)
1065 Visited.insert(T.Id);
1066 }
1067}
1068
1069// Push all definitions from the instruction node IA to an appropriate
1070// stack in DefM.
1071void DataFlowGraph::pushDefs(NodeAddr<InstrNode*> IA, DefStackMap &DefM) {
1072 NodeSet Visited;
1073#ifndef NDEBUG1
1074 std::set<RegisterId> Defined;
1075#endif
1076
1077 // The important objectives of this function are:
1078 // - to be able to handle instructions both while the graph is being
1079 // constructed, and after the graph has been constructed, and
1080 // - maintain proper ordering of definitions on the stack for each
1081 // register reference:
1082 // - if there are two or more related defs in IA (i.e. coming from
1083 // the same machine operand), then only push one def on the stack,
1084 // - if there are multiple unrelated defs of non-overlapping
1085 // subregisters of S, then the stack for S will have both (in an
1086 // unspecified order), but the order does not matter from the data-
1087 // -flow perspective.
1088
1089 for (NodeAddr<DefNode*> DA : IA.Addr->members_if(IsDef, *this)) {
1090 if (Visited.count(DA.Id))
1091 continue;
1092 if (DA.Addr->getFlags() & NodeAttrs::Clobbering)
1093 continue;
1094
1095 NodeList Rel = getRelatedRefs(IA, DA);
1096 NodeAddr<DefNode*> PDA = Rel.front();
1097 RegisterRef RR = PDA.Addr->getRegRef(*this);
1098#ifndef NDEBUG1
1099 // Assert if the register is defined in two or more unrelated defs.
1100 // This could happen if there are two or more def operands defining it.
1101 if (!Defined.insert(RR.Reg).second) {
1102 MachineInstr *MI = NodeAddr<StmtNode*>(IA).Addr->getCode();
1103 dbgs() << "Multiple definitions of register: "
1104 << Print<RegisterRef>(RR, *this) << " in\n " << *MI << "in "
1105 << printMBBReference(*MI->getParent()) << '\n';
1106 llvm_unreachable(nullptr)__builtin_unreachable();
1107 }
1108#endif
1109 // Push the definition on the stack for the register and all aliases.
1110 // The def stack traversal in linkNodeUp will check the exact aliasing.
1111 DefM[RR.Reg].push(DA);
1112 for (RegisterId A : PRI.getAliasSet(RR.Reg)) {
1113 // Check that we don't push the same def twice.
1114 assert(A != RR.Reg)((void)0);
1115 DefM[A].push(DA);
1116 }
1117 // Mark all the related defs as visited.
1118 for (NodeAddr<NodeBase*> T : Rel)
1119 Visited.insert(T.Id);
1120 }
1121}
1122
1123// Return the list of all reference nodes related to RA, including RA itself.
1124// See "getNextRelated" for the meaning of a "related reference".
1125NodeList DataFlowGraph::getRelatedRefs(NodeAddr<InstrNode*> IA,
1126 NodeAddr<RefNode*> RA) const {
1127 assert(IA.Id != 0 && RA.Id != 0)((void)0);
1128
1129 NodeList Refs;
1130 NodeId Start = RA.Id;
1131 do {
1132 Refs.push_back(RA);
1133 RA = getNextRelated(IA, RA);
1134 } while (RA.Id != 0 && RA.Id != Start);
1135 return Refs;
1136}
1137
1138// Clear all information in the graph.
1139void DataFlowGraph::reset() {
1140 Memory.clear();
1141 BlockNodes.clear();
1142 Func = NodeAddr<FuncNode*>();
1143}
1144
1145// Return the next reference node in the instruction node IA that is related
1146// to RA. Conceptually, two reference nodes are related if they refer to the
1147// same instance of a register access, but differ in flags or other minor
1148// characteristics. Specific examples of related nodes are shadow reference
1149// nodes.
1150// Return the equivalent of nullptr if there are no more related references.
1151NodeAddr<RefNode*> DataFlowGraph::getNextRelated(NodeAddr<InstrNode*> IA,
1152 NodeAddr<RefNode*> RA) const {
1153 assert(IA.Id != 0 && RA.Id != 0)((void)0);
1154
1155 auto Related = [this,RA](NodeAddr<RefNode*> TA) -> bool {
1156 if (TA.Addr->getKind() != RA.Addr->getKind())
1157 return false;
1158 if (TA.Addr->getRegRef(*this) != RA.Addr->getRegRef(*this))
1159 return false;
1160 return true;
1161 };
1162 auto RelatedStmt = [&Related,RA](NodeAddr<RefNode*> TA) -> bool {
1163 return Related(TA) &&
1164 &RA.Addr->getOp() == &TA.Addr->getOp();
1165 };
1166 auto RelatedPhi = [&Related,RA](NodeAddr<RefNode*> TA) -> bool {
1167 if (!Related(TA))
1168 return false;
1169 if (TA.Addr->getKind() != NodeAttrs::Use)
1170 return true;
1171 // For phi uses, compare predecessor blocks.
1172 const NodeAddr<const PhiUseNode*> TUA = TA;
1173 const NodeAddr<const PhiUseNode*> RUA = RA;
1174 return TUA.Addr->getPredecessor() == RUA.Addr->getPredecessor();
1175 };
1176
1177 RegisterRef RR = RA.Addr->getRegRef(*this);
1178 if (IA.Addr->getKind() == NodeAttrs::Stmt)
1179 return RA.Addr->getNextRef(RR, RelatedStmt, true, *this);
1180 return RA.Addr->getNextRef(RR, RelatedPhi, true, *this);
1181}
1182
1183// Find the next node related to RA in IA that satisfies condition P.
1184// If such a node was found, return a pair where the second element is the
1185// located node. If such a node does not exist, return a pair where the
1186// first element is the element after which such a node should be inserted,
1187// and the second element is a null-address.
1188template <typename Predicate>
1189std::pair<NodeAddr<RefNode*>,NodeAddr<RefNode*>>
1190DataFlowGraph::locateNextRef(NodeAddr<InstrNode*> IA, NodeAddr<RefNode*> RA,
1191 Predicate P) const {
1192 assert(IA.Id != 0 && RA.Id != 0)((void)0);
1193
1194 NodeAddr<RefNode*> NA;
1195 NodeId Start = RA.Id;
1196 while (true) {
1197 NA = getNextRelated(IA, RA);
1198 if (NA.Id == 0 || NA.Id == Start)
1199 break;
1200 if (P(NA))
1201 break;
1202 RA = NA;
1203 }
1204
1205 if (NA.Id != 0 && NA.Id != Start)
1206 return std::make_pair(RA, NA);
1207 return std::make_pair(RA, NodeAddr<RefNode*>());
1208}
1209
1210// Get the next shadow node in IA corresponding to RA, and optionally create
1211// such a node if it does not exist.
1212NodeAddr<RefNode*> DataFlowGraph::getNextShadow(NodeAddr<InstrNode*> IA,
1213 NodeAddr<RefNode*> RA, bool Create) {
1214 assert(IA.Id != 0 && RA.Id != 0)((void)0);
1215
1216 uint16_t Flags = RA.Addr->getFlags() | NodeAttrs::Shadow;
1217 auto IsShadow = [Flags] (NodeAddr<RefNode*> TA) -> bool {
1218 return TA.Addr->getFlags() == Flags;
1219 };
1220 auto Loc = locateNextRef(IA, RA, IsShadow);
1221 if (Loc.second.Id != 0 || !Create)
1222 return Loc.second;
1223
1224 // Create a copy of RA and mark is as shadow.
1225 NodeAddr<RefNode*> NA = cloneNode(RA);
1226 NA.Addr->setFlags(Flags | NodeAttrs::Shadow);
1227 IA.Addr->addMemberAfter(Loc.first, NA, *this);
1228 return NA;
1229}
1230
1231// Get the next shadow node in IA corresponding to RA. Return null-address
1232// if such a node does not exist.
1233NodeAddr<RefNode*> DataFlowGraph::getNextShadow(NodeAddr<InstrNode*> IA,
1234 NodeAddr<RefNode*> RA) const {
1235 assert(IA.Id != 0 && RA.Id != 0)((void)0);
1236 uint16_t Flags = RA.Addr->getFlags() | NodeAttrs::Shadow;
1237 auto IsShadow = [Flags] (NodeAddr<RefNode*> TA) -> bool {
1238 return TA.Addr->getFlags() == Flags;
1239 };
1240 return locateNextRef(IA, RA, IsShadow).second;
1241}
1242
1243// Create a new statement node in the block node BA that corresponds to
1244// the machine instruction MI.
1245void DataFlowGraph::buildStmt(NodeAddr<BlockNode*> BA, MachineInstr &In) {
1246 NodeAddr<StmtNode*> SA = newStmt(BA, &In);
1247
1248 auto isCall = [] (const MachineInstr &In) -> bool {
1249 if (In.isCall())
1250 return true;
1251 // Is tail call?
1252 if (In.isBranch()) {
1253 for (const MachineOperand &Op : In.operands())
1254 if (Op.isGlobal() || Op.isSymbol())
1255 return true;
1256 // Assume indirect branches are calls. This is for the purpose of
1257 // keeping implicit operands, and so it won't hurt on intra-function
1258 // indirect branches.
1259 if (In.isIndirectBranch())
1260 return true;
1261 }
1262 return false;
1263 };
1264
1265 auto isDefUndef = [this] (const MachineInstr &In, RegisterRef DR) -> bool {
1266 // This instruction defines DR. Check if there is a use operand that
1267 // would make DR live on entry to the instruction.
1268 for (const MachineOperand &Op : In.operands()) {
1269 if (!Op.isReg() || Op.getReg() == 0 || !Op.isUse() || Op.isUndef())
1270 continue;
1271 RegisterRef UR = makeRegRef(Op);
1272 if (PRI.alias(DR, UR))
1273 return false;
1274 }
1275 return true;
1276 };
1277
1278 bool IsCall = isCall(In);
1279 unsigned NumOps = In.getNumOperands();
1280
1281 // Avoid duplicate implicit defs. This will not detect cases of implicit
1282 // defs that define registers that overlap, but it is not clear how to
1283 // interpret that in the absence of explicit defs. Overlapping explicit
1284 // defs are likely illegal already.
1285 BitVector DoneDefs(TRI.getNumRegs());
1286 // Process explicit defs first.
1287 for (unsigned OpN = 0; OpN < NumOps; ++OpN) {
1288 MachineOperand &Op = In.getOperand(OpN);
1289 if (!Op.isReg() || !Op.isDef() || Op.isImplicit())
1290 continue;
1291 Register R = Op.getReg();
1292 if (!R || !Register::isPhysicalRegister(R))
1293 continue;
1294 uint16_t Flags = NodeAttrs::None;
1295 if (TOI.isPreserving(In, OpN)) {
1296 Flags |= NodeAttrs::Preserving;
1297 // If the def is preserving, check if it is also undefined.
1298 if (isDefUndef(In, makeRegRef(Op)))
1299 Flags |= NodeAttrs::Undef;
1300 }
1301 if (TOI.isClobbering(In, OpN))
1302 Flags |= NodeAttrs::Clobbering;
1303 if (TOI.isFixedReg(In, OpN))
1304 Flags |= NodeAttrs::Fixed;
1305 if (IsCall && Op.isDead())
1306 Flags |= NodeAttrs::Dead;
1307 NodeAddr<DefNode*> DA = newDef(SA, Op, Flags);
1308 SA.Addr->addMember(DA, *this);
1309 assert(!DoneDefs.test(R))((void)0);
1310 DoneDefs.set(R);
1311 }
1312
1313 // Process reg-masks (as clobbers).
1314 BitVector DoneClobbers(TRI.getNumRegs());
1315 for (unsigned OpN = 0; OpN < NumOps; ++OpN) {
1316 MachineOperand &Op = In.getOperand(OpN);
1317 if (!Op.isRegMask())
1318 continue;
1319 uint16_t Flags = NodeAttrs::Clobbering | NodeAttrs::Fixed |
1320 NodeAttrs::Dead;
1321 NodeAddr<DefNode*> DA = newDef(SA, Op, Flags);
1322 SA.Addr->addMember(DA, *this);
1323 // Record all clobbered registers in DoneDefs.
1324 const uint32_t *RM = Op.getRegMask();
1325 for (unsigned i = 1, e = TRI.getNumRegs(); i != e; ++i)
1326 if (!(RM[i/32] & (1u << (i%32))))
1327 DoneClobbers.set(i);
1328 }
1329
1330 // Process implicit defs, skipping those that have already been added
1331 // as explicit.
1332 for (unsigned OpN = 0; OpN < NumOps; ++OpN) {
1333 MachineOperand &Op = In.getOperand(OpN);
1334 if (!Op.isReg() || !Op.isDef() || !Op.isImplicit())
1335 continue;
1336 Register R = Op.getReg();
1337 if (!R || !Register::isPhysicalRegister(R) || DoneDefs.test(R))
1338 continue;
1339 RegisterRef RR = makeRegRef(Op);
1340 uint16_t Flags = NodeAttrs::None;
1341 if (TOI.isPreserving(In, OpN)) {
1342 Flags |= NodeAttrs::Preserving;
1343 // If the def is preserving, check if it is also undefined.
1344 if (isDefUndef(In, RR))
1345 Flags |= NodeAttrs::Undef;
1346 }
1347 if (TOI.isClobbering(In, OpN))
1348 Flags |= NodeAttrs::Clobbering;
1349 if (TOI.isFixedReg(In, OpN))
1350 Flags |= NodeAttrs::Fixed;
1351 if (IsCall && Op.isDead()) {
1352 if (DoneClobbers.test(R))
1353 continue;
1354 Flags |= NodeAttrs::Dead;
1355 }
1356 NodeAddr<DefNode*> DA = newDef(SA, Op, Flags);
1357 SA.Addr->addMember(DA, *this);
1358 DoneDefs.set(R);
1359 }
1360
1361 for (unsigned OpN = 0; OpN < NumOps; ++OpN) {
1362 MachineOperand &Op = In.getOperand(OpN);
1363 if (!Op.isReg() || !Op.isUse())
1364 continue;
1365 Register R = Op.getReg();
1366 if (!R || !Register::isPhysicalRegister(R))
1367 continue;
1368 uint16_t Flags = NodeAttrs::None;
1369 if (Op.isUndef())
1370 Flags |= NodeAttrs::Undef;
1371 if (TOI.isFixedReg(In, OpN))
1372 Flags |= NodeAttrs::Fixed;
1373 NodeAddr<UseNode*> UA = newUse(SA, Op, Flags);
1374 SA.Addr->addMember(UA, *this);
1375 }
1376}
1377
1378// Scan all defs in the block node BA and record in PhiM the locations of
1379// phi nodes corresponding to these defs.
1380void DataFlowGraph::recordDefsForDF(BlockRefsMap &PhiM,
1381 NodeAddr<BlockNode*> BA) {
1382 // Check all defs from block BA and record them in each block in BA's
1383 // iterated dominance frontier. This information will later be used to
1384 // create phi nodes.
1385 MachineBasicBlock *BB = BA.Addr->getCode();
1386 assert(BB)((void)0);
1387 auto DFLoc = MDF.find(BB);
1388 if (DFLoc == MDF.end() || DFLoc->second.empty())
1389 return;
1390
1391 // Traverse all instructions in the block and collect the set of all
1392 // defined references. For each reference there will be a phi created
1393 // in the block's iterated dominance frontier.
1394 // This is done to make sure that each defined reference gets only one
1395 // phi node, even if it is defined multiple times.
1396 RegisterSet Defs;
1397 for (NodeAddr<InstrNode*> IA : BA.Addr->members(*this))
1398 for (NodeAddr<RefNode*> RA : IA.Addr->members_if(IsDef, *this))
1399 Defs.insert(RA.Addr->getRegRef(*this));
1400
1401 // Calculate the iterated dominance frontier of BB.
1402 const MachineDominanceFrontier::DomSetType &DF = DFLoc->second;
1403 SetVector<MachineBasicBlock*> IDF(DF.begin(), DF.end());
1404 for (unsigned i = 0; i < IDF.size(); ++i) {
1405 auto F = MDF.find(IDF[i]);
1406 if (F != MDF.end())
1407 IDF.insert(F->second.begin(), F->second.end());
1408 }
1409
1410 // Finally, add the set of defs to each block in the iterated dominance
1411 // frontier.
1412 for (auto DB : IDF) {
1413 NodeAddr<BlockNode*> DBA = findBlock(DB);
1414 PhiM[DBA.Id].insert(Defs.begin(), Defs.end());
1415 }
1416}
1417
1418// Given the locations of phi nodes in the map PhiM, create the phi nodes
1419// that are located in the block node BA.
1420void DataFlowGraph::buildPhis(BlockRefsMap &PhiM, RegisterSet &AllRefs,
1421 NodeAddr<BlockNode*> BA) {
1422 // Check if this blocks has any DF defs, i.e. if there are any defs
1423 // that this block is in the iterated dominance frontier of.
1424 auto HasDF = PhiM.find(BA.Id);
1425 if (HasDF == PhiM.end() || HasDF->second.empty())
1426 return;
1427
1428 // First, remove all R in Refs in such that there exists T in Refs
1429 // such that T covers R. In other words, only leave those refs that
1430 // are not covered by another ref (i.e. maximal with respect to covering).
1431
1432 auto MaxCoverIn = [this] (RegisterRef RR, RegisterSet &RRs) -> RegisterRef {
1433 for (RegisterRef I : RRs)
1434 if (I != RR && RegisterAggr::isCoverOf(I, RR, PRI))
1435 RR = I;
1436 return RR;
1437 };
1438
1439 RegisterSet MaxDF;
1440 for (RegisterRef I : HasDF->second)
1441 MaxDF.insert(MaxCoverIn(I, HasDF->second));
1442
1443 std::vector<RegisterRef> MaxRefs;
1444 for (RegisterRef I : MaxDF)
1445 MaxRefs.push_back(MaxCoverIn(I, AllRefs));
1446
1447 // Now, for each R in MaxRefs, get the alias closure of R. If the closure
1448 // only has R in it, create a phi a def for R. Otherwise, create a phi,
1449 // and add a def for each S in the closure.
1450
1451 // Sort the refs so that the phis will be created in a deterministic order.
1452 llvm::sort(MaxRefs);
1453 // Remove duplicates.
1454 auto NewEnd = std::unique(MaxRefs.begin(), MaxRefs.end());
1455 MaxRefs.erase(NewEnd, MaxRefs.end());
1456
1457 auto Aliased = [this,&MaxRefs](RegisterRef RR,
1458 std::vector<unsigned> &Closure) -> bool {
1459 for (unsigned I : Closure)
1460 if (PRI.alias(RR, MaxRefs[I]))
1461 return true;
1462 return false;
1463 };
1464
1465 // Prepare a list of NodeIds of the block's predecessors.
1466 NodeList Preds;
1467 const MachineBasicBlock *MBB = BA.Addr->getCode();
1468 for (MachineBasicBlock *PB : MBB->predecessors())
1469 Preds.push_back(findBlock(PB));
1470
1471 while (!MaxRefs.empty()) {
1472 // Put the first element in the closure, and then add all subsequent
1473 // elements from MaxRefs to it, if they alias at least one element
1474 // already in the closure.
1475 // ClosureIdx: vector of indices in MaxRefs of members of the closure.
1476 std::vector<unsigned> ClosureIdx = { 0 };
1477 for (unsigned i = 1; i != MaxRefs.size(); ++i)
1478 if (Aliased(MaxRefs[i], ClosureIdx))
1479 ClosureIdx.push_back(i);
1480
1481 // Build a phi for the closure.
1482 unsigned CS = ClosureIdx.size();
1483 NodeAddr<PhiNode*> PA = newPhi(BA);
1484
1485 // Add defs.
1486 for (unsigned X = 0; X != CS; ++X) {
1487 RegisterRef RR = MaxRefs[ClosureIdx[X]];
1488 uint16_t PhiFlags = NodeAttrs::PhiRef | NodeAttrs::Preserving;
1489 NodeAddr<DefNode*> DA = newDef(PA, RR, PhiFlags);
1490 PA.Addr->addMember(DA, *this);
1491 }
1492 // Add phi uses.
1493 for (NodeAddr<BlockNode*> PBA : Preds) {
1494 for (unsigned X = 0; X != CS; ++X) {
1495 RegisterRef RR = MaxRefs[ClosureIdx[X]];
1496 NodeAddr<PhiUseNode*> PUA = newPhiUse(PA, RR, PBA);
1497 PA.Addr->addMember(PUA, *this);
1498 }
1499 }
1500
1501 // Erase from MaxRefs all elements in the closure.
1502 auto Begin = MaxRefs.begin();
1503 for (unsigned i = ClosureIdx.size(); i != 0; --i)
1504 MaxRefs.erase(Begin + ClosureIdx[i-1]);
1505 }
1506}
1507
1508// Remove any unneeded phi nodes that were created during the build process.
1509void DataFlowGraph::removeUnusedPhis() {
1510 // This will remove unused phis, i.e. phis where each def does not reach
1511 // any uses or other defs. This will not detect or remove circular phi
1512 // chains that are otherwise dead. Unused/dead phis are created during
1513 // the build process and this function is intended to remove these cases
1514 // that are easily determinable to be unnecessary.
1515
1516 SetVector<NodeId> PhiQ;
1517 for (NodeAddr<BlockNode*> BA : Func.Addr->members(*this)) {
1518 for (auto P : BA.Addr->members_if(IsPhi, *this))
1519 PhiQ.insert(P.Id);
1520 }
1521
1522 static auto HasUsedDef = [](NodeList &Ms) -> bool {
1523 for (NodeAddr<NodeBase*> M : Ms) {
1524 if (M.Addr->getKind() != NodeAttrs::Def)
1525 continue;
1526 NodeAddr<DefNode*> DA = M;
1527 if (DA.Addr->getReachedDef() != 0 || DA.Addr->getReachedUse() != 0)
1528 return true;
1529 }
1530 return false;
1531 };
1532
1533 // Any phi, if it is removed, may affect other phis (make them dead).
1534 // For each removed phi, collect the potentially affected phis and add
1535 // them back to the queue.
1536 while (!PhiQ.empty()) {
1537 auto PA = addr<PhiNode*>(PhiQ[0]);
1538 PhiQ.remove(PA.Id);
1539 NodeList Refs = PA.Addr->members(*this);
1540 if (HasUsedDef(Refs))
1541 continue;
1542 for (NodeAddr<RefNode*> RA : Refs) {
1543 if (NodeId RD = RA.Addr->getReachingDef()) {
1544 auto RDA = addr<DefNode*>(RD);
1545 NodeAddr<InstrNode*> OA = RDA.Addr->getOwner(*this);
1546 if (IsPhi(OA))
1547 PhiQ.insert(OA.Id);
1548 }
1549 if (RA.Addr->isDef())
1550 unlinkDef(RA, true);
1551 else
1552 unlinkUse(RA, true);
1553 }
1554 NodeAddr<BlockNode*> BA = PA.Addr->getOwner(*this);
1555 BA.Addr->removeMember(PA, *this);
1556 }
1557}
1558
1559// For a given reference node TA in an instruction node IA, connect the
1560// reaching def of TA to the appropriate def node. Create any shadow nodes
1561// as appropriate.
1562template <typename T>
1563void DataFlowGraph::linkRefUp(NodeAddr<InstrNode*> IA, NodeAddr<T> TA,
1564 DefStack &DS) {
1565 if (DS.empty())
1566 return;
1567 RegisterRef RR = TA.Addr->getRegRef(*this);
1568 NodeAddr<T> TAP;
1569
1570 // References from the def stack that have been examined so far.
1571 RegisterAggr Defs(PRI);
1572
1573 for (auto I = DS.top(), E = DS.bottom(); I != E; I.down()) {
1574 RegisterRef QR = I->Addr->getRegRef(*this);
1575
1576 // Skip all defs that are aliased to any of the defs that we have already
1577 // seen. If this completes a cover of RR, stop the stack traversal.
1578 bool Alias = Defs.hasAliasOf(QR);
1579 bool Cover = Defs.insert(QR).hasCoverOf(RR);
1580 if (Alias) {
1581 if (Cover)
1582 break;
1583 continue;
1584 }
1585
1586 // The reaching def.
1587 NodeAddr<DefNode*> RDA = *I;
1588
1589 // Pick the reached node.
1590 if (TAP.Id == 0) {
1591 TAP = TA;
1592 } else {
1593 // Mark the existing ref as "shadow" and create a new shadow.
1594 TAP.Addr->setFlags(TAP.Addr->getFlags() | NodeAttrs::Shadow);
1595 TAP = getNextShadow(IA, TAP, true);
1596 }
1597
1598 // Create the link.
1599 TAP.Addr->linkToDef(TAP.Id, RDA);
1600
1601 if (Cover)
1602 break;
1603 }
1604}
1605
1606// Create data-flow links for all reference nodes in the statement node SA.
1607template <typename Predicate>
1608void DataFlowGraph::linkStmtRefs(DefStackMap &DefM, NodeAddr<StmtNode*> SA,
1609 Predicate P) {
1610#ifndef NDEBUG1
1611 RegisterSet Defs;
1612#endif
1613
1614 // Link all nodes (upwards in the data-flow) with their reaching defs.
1615 for (NodeAddr<RefNode*> RA : SA.Addr->members_if(P, *this)) {
1616 uint16_t Kind = RA.Addr->getKind();
1617 assert(Kind == NodeAttrs::Def || Kind == NodeAttrs::Use)((void)0);
1618 RegisterRef RR = RA.Addr->getRegRef(*this);
1619#ifndef NDEBUG1
1620 // Do not expect multiple defs of the same reference.
1621 assert(Kind != NodeAttrs::Def || !Defs.count(RR))((void)0);
1622 Defs.insert(RR);
1623#endif
1624
1625 auto F = DefM.find(RR.Reg);
1626 if (F == DefM.end())
1627 continue;
1628 DefStack &DS = F->second;
1629 if (Kind == NodeAttrs::Use)
1630 linkRefUp<UseNode*>(SA, RA, DS);
1631 else if (Kind == NodeAttrs::Def)
1632 linkRefUp<DefNode*>(SA, RA, DS);
1633 else
1634 llvm_unreachable("Unexpected node in instruction")__builtin_unreachable();
1635 }
1636}
1637
1638// Create data-flow links for all instructions in the block node BA. This
1639// will include updating any phi nodes in BA.
1640void DataFlowGraph::linkBlockRefs(DefStackMap &DefM, NodeAddr<BlockNode*> BA) {
1641 // Push block delimiters.
1642 markBlock(BA.Id, DefM);
1643
1644 auto IsClobber = [] (NodeAddr<RefNode*> RA) -> bool {
1645 return IsDef(RA) && (RA.Addr->getFlags() & NodeAttrs::Clobbering);
1646 };
1647 auto IsNoClobber = [] (NodeAddr<RefNode*> RA) -> bool {
1648 return IsDef(RA) && !(RA.Addr->getFlags() & NodeAttrs::Clobbering);
1649 };
1650
1651 assert(BA.Addr && "block node address is needed to create a data-flow link")((void)0);
1652 // For each non-phi instruction in the block, link all the defs and uses
1653 // to their reaching defs. For any member of the block (including phis),
1654 // push the defs on the corresponding stacks.
1655 for (NodeAddr<InstrNode*> IA : BA.Addr->members(*this)) {
1656 // Ignore phi nodes here. They will be linked part by part from the
1657 // predecessors.
1658 if (IA.Addr->getKind() == NodeAttrs::Stmt) {
1659 linkStmtRefs(DefM, IA, IsUse);
1660 linkStmtRefs(DefM, IA, IsClobber);
1661 }
1662
1663 // Push the definitions on the stack.
1664 pushClobbers(IA, DefM);
1665
1666 if (IA.Addr->getKind() == NodeAttrs::Stmt)
1667 linkStmtRefs(DefM, IA, IsNoClobber);
1668
1669 pushDefs(IA, DefM);
1670 }
1671
1672 // Recursively process all children in the dominator tree.
1673 MachineDomTreeNode *N = MDT.getNode(BA.Addr->getCode());
1674 for (auto I : *N) {
1675 MachineBasicBlock *SB = I->getBlock();
1676 NodeAddr<BlockNode*> SBA = findBlock(SB);
1677 linkBlockRefs(DefM, SBA);
1678 }
1679
1680 // Link the phi uses from the successor blocks.
1681 auto IsUseForBA = [BA](NodeAddr<NodeBase*> NA) -> bool {
1682 if (NA.Addr->getKind() != NodeAttrs::Use)
1683 return false;
1684 assert(NA.Addr->getFlags() & NodeAttrs::PhiRef)((void)0);
1685 NodeAddr<PhiUseNode*> PUA = NA;
1686 return PUA.Addr->getPredecessor() == BA.Id;
1687 };
1688
1689 RegisterSet EHLiveIns = getLandingPadLiveIns();
1690 MachineBasicBlock *MBB = BA.Addr->getCode();
1691
1692 for (MachineBasicBlock *SB : MBB->successors()) {
1693 bool IsEHPad = SB->isEHPad();
1694 NodeAddr<BlockNode*> SBA = findBlock(SB);
1695 for (NodeAddr<InstrNode*> IA : SBA.Addr->members_if(IsPhi, *this)) {
1696 // Do not link phi uses for landing pad live-ins.
1697 if (IsEHPad) {
1698 // Find what register this phi is for.
1699 NodeAddr<RefNode*> RA = IA.Addr->getFirstMember(*this);
1700 assert(RA.Id != 0)((void)0);
1701 if (EHLiveIns.count(RA.Addr->getRegRef(*this)))
1702 continue;
1703 }
1704 // Go over each phi use associated with MBB, and link it.
1705 for (auto U : IA.Addr->members_if(IsUseForBA, *this)) {
1706 NodeAddr<PhiUseNode*> PUA = U;
1707 RegisterRef RR = PUA.Addr->getRegRef(*this);
1708 linkRefUp<UseNode*>(IA, PUA, DefM[RR.Reg]);
1709 }
1710 }
1711 }
1712
1713 // Pop all defs from this block from the definition stacks.
1714 releaseBlock(BA.Id, DefM);
1715}
1716
1717// Remove the use node UA from any data-flow and structural links.
1718void DataFlowGraph::unlinkUseDF(NodeAddr<UseNode*> UA) {
1719 NodeId RD = UA.Addr->getReachingDef();
1720 NodeId Sib = UA.Addr->getSibling();
1721
1722 if (RD == 0) {
1723 assert(Sib == 0)((void)0);
1724 return;
1725 }
1726
1727 auto RDA = addr<DefNode*>(RD);
1728 auto TA = addr<UseNode*>(RDA.Addr->getReachedUse());
1729 if (TA.Id == UA.Id) {
1730 RDA.Addr->setReachedUse(Sib);
1731 return;
1732 }
1733
1734 while (TA.Id != 0) {
1735 NodeId S = TA.Addr->getSibling();
1736 if (S == UA.Id) {
1737 TA.Addr->setSibling(UA.Addr->getSibling());
1738 return;
1739 }
1740 TA = addr<UseNode*>(S);
1741 }
1742}
1743
1744// Remove the def node DA from any data-flow and structural links.
1745void DataFlowGraph::unlinkDefDF(NodeAddr<DefNode*> DA) {
1746 //
1747 // RD
1748 // | reached
1749 // | def
1750 // :
1751 // .
1752 // +----+
1753 // ... -- | DA | -- ... -- 0 : sibling chain of DA
1754 // +----+
1755 // | | reached
1756 // | : def
1757 // | .
1758 // | ... : Siblings (defs)
1759 // |
1760 // : reached
1761 // . use
1762 // ... : sibling chain of reached uses
1763
1764 NodeId RD = DA.Addr->getReachingDef();
1765
1766 // Visit all siblings of the reached def and reset their reaching defs.
1767 // Also, defs reached by DA are now "promoted" to being reached by RD,
1768 // so all of them will need to be spliced into the sibling chain where
1769 // DA belongs.
1770 auto getAllNodes = [this] (NodeId N) -> NodeList {
1771 NodeList Res;
1772 while (N) {
1773 auto RA = addr<RefNode*>(N);
1774 // Keep the nodes in the exact sibling order.
1775 Res.push_back(RA);
1776 N = RA.Addr->getSibling();
1777 }
1778 return Res;
1779 };
1780 NodeList ReachedDefs = getAllNodes(DA.Addr->getReachedDef());
1781 NodeList ReachedUses = getAllNodes(DA.Addr->getReachedUse());
1782
1783 if (RD == 0) {
1784 for (NodeAddr<RefNode*> I : ReachedDefs)
1785 I.Addr->setSibling(0);
1786 for (NodeAddr<RefNode*> I : ReachedUses)
1787 I.Addr->setSibling(0);
1788 }
1789 for (NodeAddr<DefNode*> I : ReachedDefs)
1790 I.Addr->setReachingDef(RD);
1791 for (NodeAddr<UseNode*> I : ReachedUses)
1792 I.Addr->setReachingDef(RD);
1793
1794 NodeId Sib = DA.Addr->getSibling();
1795 if (RD == 0) {
1796 assert(Sib == 0)((void)0);
1797 return;
1798 }
1799
1800 // Update the reaching def node and remove DA from the sibling list.
1801 auto RDA = addr<DefNode*>(RD);
1802 auto TA = addr<DefNode*>(RDA.Addr->getReachedDef());
1803 if (TA.Id == DA.Id) {
1804 // If DA is the first reached def, just update the RD's reached def
1805 // to the DA's sibling.
1806 RDA.Addr->setReachedDef(Sib);
1807 } else {
1808 // Otherwise, traverse the sibling list of the reached defs and remove
1809 // DA from it.
1810 while (TA.Id != 0) {
1811 NodeId S = TA.Addr->getSibling();
1812 if (S == DA.Id) {
1813 TA.Addr->setSibling(Sib);
1814 break;
1815 }
1816 TA = addr<DefNode*>(S);
1817 }
1818 }
1819
1820 // Splice the DA's reached defs into the RDA's reached def chain.
1821 if (!ReachedDefs.empty()) {
1822 auto Last = NodeAddr<DefNode*>(ReachedDefs.back());
1823 Last.Addr->setSibling(RDA.Addr->getReachedDef());
1824 RDA.Addr->setReachedDef(ReachedDefs.front().Id);
1825 }
1826 // Splice the DA's reached uses into the RDA's reached use chain.
1827 if (!ReachedUses.empty()) {
1828 auto Last = NodeAddr<UseNode*>(ReachedUses.back());
1829 Last.Addr->setSibling(RDA.Addr->getReachedUse());
1830 RDA.Addr->setReachedUse(ReachedUses.front().Id);
1831 }
1832}