Bug Summary

File:src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/ProfileData/InstrProf.cpp
Warning:line 498, column 24
Dereference of null pointer (loaded from variable 'P')

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 InstrProf.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 static -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" -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 -stack-protector 2 -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/ProfileData/InstrProf.cpp

/usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/ProfileData/InstrProf.cpp

→
1//===- InstrProf.cpp - Instrumented profiling format support --------------===//
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 contains support for clang's instrumentation based PGO and
10// coverage.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/ProfileData/InstrProf.h"
15#include "llvm/ADT/ArrayRef.h"
16#include "llvm/ADT/SmallString.h"
17#include "llvm/ADT/SmallVector.h"
18#include "llvm/ADT/StringExtras.h"
19#include "llvm/ADT/StringRef.h"
20#include "llvm/ADT/Triple.h"
21#include "llvm/Config/config.h"
22#include "llvm/IR/Constant.h"
23#include "llvm/IR/Constants.h"
24#include "llvm/IR/Function.h"
25#include "llvm/IR/GlobalValue.h"
26#include "llvm/IR/GlobalVariable.h"
27#include "llvm/IR/Instruction.h"
28#include "llvm/IR/LLVMContext.h"
29#include "llvm/IR/MDBuilder.h"
30#include "llvm/IR/Metadata.h"
31#include "llvm/IR/Module.h"
32#include "llvm/IR/Type.h"
33#include "llvm/ProfileData/InstrProfReader.h"
34#include "llvm/Support/Casting.h"
35#include "llvm/Support/CommandLine.h"
36#include "llvm/Support/Compiler.h"
37#include "llvm/Support/Compression.h"
38#include "llvm/Support/Endian.h"
39#include "llvm/Support/Error.h"
40#include "llvm/Support/ErrorHandling.h"
41#include "llvm/Support/LEB128.h"
42#include "llvm/Support/ManagedStatic.h"
43#include "llvm/Support/MathExtras.h"
44#include "llvm/Support/Path.h"
45#include "llvm/Support/SwapByteOrder.h"
46#include <algorithm>
47#include <cassert>
48#include <cstddef>
49#include <cstdint>
50#include <cstring>
51#include <memory>
52#include <string>
53#include <system_error>
54#include <utility>
55#include <vector>
56
57using namespace llvm;
58
59static cl::opt<bool> StaticFuncFullModulePrefix(
60 "static-func-full-module-prefix", cl::init(true), cl::Hidden,
61 cl::desc("Use full module build paths in the profile counter names for "
62 "static functions."));
63
64// This option is tailored to users that have different top-level directory in
65// profile-gen and profile-use compilation. Users need to specific the number
66// of levels to strip. A value larger than the number of directories in the
67// source file will strip all the directory names and only leave the basename.
68//
69// Note current ThinLTO module importing for the indirect-calls assumes
70// the source directory name not being stripped. A non-zero option value here
71// can potentially prevent some inter-module indirect-call-promotions.
72static cl::opt<unsigned> StaticFuncStripDirNamePrefix(
73 "static-func-strip-dirname-prefix", cl::init(0), cl::Hidden,
74 cl::desc("Strip specified level of directory name from source path in "
75 "the profile counter name for static functions."));
76
77static std::string getInstrProfErrString(instrprof_error Err) {
78 switch (Err) {
79 case instrprof_error::success:
80 return "success";
81 case instrprof_error::eof:
82 return "end of File";
83 case instrprof_error::unrecognized_format:
84 return "unrecognized instrumentation profile encoding format";
85 case instrprof_error::bad_magic:
86 return "invalid instrumentation profile data (bad magic)";
87 case instrprof_error::bad_header:
88 return "invalid instrumentation profile data (file header is corrupt)";
89 case instrprof_error::unsupported_version:
90 return "unsupported instrumentation profile format version";
91 case instrprof_error::unsupported_hash_type:
92 return "unsupported instrumentation profile hash type";
93 case instrprof_error::too_large:
94 return "too much profile data";
95 case instrprof_error::truncated:
96 return "truncated profile data";
97 case instrprof_error::malformed:
98 return "malformed instrumentation profile data";
99 case instrprof_error::invalid_prof:
100 return "invalid profile created. Please file a bug "
101 "at: " BUG_REPORT_URL"https://bugs.llvm.org/"
102 " and include the profraw files that caused this error.";
103 case instrprof_error::unknown_function:
104 return "no profile data available for function";
105 case instrprof_error::hash_mismatch:
106 return "function control flow change detected (hash mismatch)";
107 case instrprof_error::count_mismatch:
108 return "function basic block count change detected (counter mismatch)";
109 case instrprof_error::counter_overflow:
110 return "counter overflow";
111 case instrprof_error::value_site_count_mismatch:
112 return "function value site count change detected (counter mismatch)";
113 case instrprof_error::compress_failed:
114 return "failed to compress data (zlib)";
115 case instrprof_error::uncompress_failed:
116 return "failed to uncompress data (zlib)";
117 case instrprof_error::empty_raw_profile:
118 return "empty raw profile file";
119 case instrprof_error::zlib_unavailable:
120 return "profile uses zlib compression but the profile reader was built "
121 "without zlib support";
122 }
123 llvm_unreachable("A value of instrprof_error has no message.")__builtin_unreachable();
124}
125
126namespace {
127
128// FIXME: This class is only here to support the transition to llvm::Error. It
129// will be removed once this transition is complete. Clients should prefer to
130// deal with the Error value directly, rather than converting to error_code.
131class InstrProfErrorCategoryType : public std::error_category {
132 const char *name() const noexcept override { return "llvm.instrprof"; }
133
134 std::string message(int IE) const override {
135 return getInstrProfErrString(static_cast<instrprof_error>(IE));
136 }
137};
138
139} // end anonymous namespace
140
141static ManagedStatic<InstrProfErrorCategoryType> ErrorCategory;
142
143const std::error_category &llvm::instrprof_category() {
144 return *ErrorCategory;
145}
146
147namespace {
148
149const char *InstrProfSectNameCommon[] = {
150#define INSTR_PROF_SECT_ENTRY(Kind, SectNameCommon, SectNameCoff, Prefix) \
151 SectNameCommon,
152#include "llvm/ProfileData/InstrProfData.inc"
153};
154
155const char *InstrProfSectNameCoff[] = {
156#define INSTR_PROF_SECT_ENTRY(Kind, SectNameCommon, SectNameCoff, Prefix) \
157 SectNameCoff,
158#include "llvm/ProfileData/InstrProfData.inc"
159};
160
161const char *InstrProfSectNamePrefix[] = {
162#define INSTR_PROF_SECT_ENTRY(Kind, SectNameCommon, SectNameCoff, Prefix) \
163 Prefix,
164#include "llvm/ProfileData/InstrProfData.inc"
165};
166
167} // namespace
168
169namespace llvm {
170
171cl::opt<bool> DoInstrProfNameCompression(
172 "enable-name-compression",
173 cl::desc("Enable name/filename string compression"), cl::init(true));
174
175std::string getInstrProfSectionName(InstrProfSectKind IPSK,
176 Triple::ObjectFormatType OF,
177 bool AddSegmentInfo) {
178 std::string SectName;
179
180 if (OF == Triple::MachO && AddSegmentInfo)
181 SectName = InstrProfSectNamePrefix[IPSK];
182
183 if (OF == Triple::COFF)
184 SectName += InstrProfSectNameCoff[IPSK];
185 else
186 SectName += InstrProfSectNameCommon[IPSK];
187
188 if (OF == Triple::MachO && IPSK == IPSK_data && AddSegmentInfo)
189 SectName += ",regular,live_support";
190
191 return SectName;
192}
193
194void SoftInstrProfErrors::addError(instrprof_error IE) {
195 if (IE == instrprof_error::success)
196 return;
197
198 if (FirstError == instrprof_error::success)
199 FirstError = IE;
200
201 switch (IE) {
202 case instrprof_error::hash_mismatch:
203 ++NumHashMismatches;
204 break;
205 case instrprof_error::count_mismatch:
206 ++NumCountMismatches;
207 break;
208 case instrprof_error::counter_overflow:
209 ++NumCounterOverflows;
210 break;
211 case instrprof_error::value_site_count_mismatch:
212 ++NumValueSiteCountMismatches;
213 break;
214 default:
215 llvm_unreachable("Not a soft error")__builtin_unreachable();
216 }
217}
218
219std::string InstrProfError::message() const {
220 return getInstrProfErrString(Err);
221}
222
223char InstrProfError::ID = 0;
224
225std::string getPGOFuncName(StringRef RawFuncName,
226 GlobalValue::LinkageTypes Linkage,
227 StringRef FileName,
228 uint64_t Version LLVM_ATTRIBUTE_UNUSED__attribute__((__unused__))) {
229 return GlobalValue::getGlobalIdentifier(RawFuncName, Linkage, FileName);
230}
231
232// Strip NumPrefix level of directory name from PathNameStr. If the number of
233// directory separators is less than NumPrefix, strip all the directories and
234// leave base file name only.
235static StringRef stripDirPrefix(StringRef PathNameStr, uint32_t NumPrefix) {
236 uint32_t Count = NumPrefix;
237 uint32_t Pos = 0, LastPos = 0;
238 for (auto & CI : PathNameStr) {
239 ++Pos;
240 if (llvm::sys::path::is_separator(CI)) {
241 LastPos = Pos;
242 --Count;
243 }
244 if (Count == 0)
245 break;
246 }
247 return PathNameStr.substr(LastPos);
248}
249
250// Return the PGOFuncName. This function has some special handling when called
251// in LTO optimization. The following only applies when calling in LTO passes
252// (when \c InLTO is true): LTO's internalization privatizes many global linkage
253// symbols. This happens after value profile annotation, but those internal
254// linkage functions should not have a source prefix.
255// Additionally, for ThinLTO mode, exported internal functions are promoted
256// and renamed. We need to ensure that the original internal PGO name is
257// used when computing the GUID that is compared against the profiled GUIDs.
258// To differentiate compiler generated internal symbols from original ones,
259// PGOFuncName meta data are created and attached to the original internal
260// symbols in the value profile annotation step
261// (PGOUseFunc::annotateIndirectCallSites). If a symbol does not have the meta
262// data, its original linkage must be non-internal.
263std::string getPGOFuncName(const Function &F, bool InLTO, uint64_t Version) {
264 if (!InLTO) {
265 StringRef FileName(F.getParent()->getSourceFileName());
266 uint32_t StripLevel = StaticFuncFullModulePrefix ? 0 : (uint32_t)-1;
267 if (StripLevel < StaticFuncStripDirNamePrefix)
268 StripLevel = StaticFuncStripDirNamePrefix;
269 if (StripLevel)
270 FileName = stripDirPrefix(FileName, StripLevel);
271 return getPGOFuncName(F.getName(), F.getLinkage(), FileName, Version);
272 }
273
274 // In LTO mode (when InLTO is true), first check if there is a meta data.
275 if (MDNode *MD = getPGOFuncNameMetadata(F)) {
276 StringRef S = cast<MDString>(MD->getOperand(0))->getString();
277 return S.str();
278 }
279
280 // If there is no meta data, the function must be a global before the value
281 // profile annotation pass. Its current linkage may be internal if it is
282 // internalized in LTO mode.
283 return getPGOFuncName(F.getName(), GlobalValue::ExternalLinkage, "");
284}
285
286StringRef getFuncNameWithoutPrefix(StringRef PGOFuncName, StringRef FileName) {
287 if (FileName.empty())
288 return PGOFuncName;
289 // Drop the file name including ':'. See also getPGOFuncName.
290 if (PGOFuncName.startswith(FileName))
291 PGOFuncName = PGOFuncName.drop_front(FileName.size() + 1);
292 return PGOFuncName;
293}
294
295// \p FuncName is the string used as profile lookup key for the function. A
296// symbol is created to hold the name. Return the legalized symbol name.
297std::string getPGOFuncNameVarName(StringRef FuncName,
298 GlobalValue::LinkageTypes Linkage) {
299 std::string VarName = std::string(getInstrProfNameVarPrefix());
300 VarName += FuncName;
301
302 if (!GlobalValue::isLocalLinkage(Linkage))
303 return VarName;
304
305 // Now fix up illegal chars in local VarName that may upset the assembler.
306 const char *InvalidChars = "-:<>/\"'";
307 size_t found = VarName.find_first_of(InvalidChars);
308 while (found != std::string::npos) {
309 VarName[found] = '_';
310 found = VarName.find_first_of(InvalidChars, found + 1);
311 }
312 return VarName;
313}
314
315GlobalVariable *createPGOFuncNameVar(Module &M,
316 GlobalValue::LinkageTypes Linkage,
317 StringRef PGOFuncName) {
318 // We generally want to match the function's linkage, but available_externally
319 // and extern_weak both have the wrong semantics, and anything that doesn't
320 // need to link across compilation units doesn't need to be visible at all.
321 if (Linkage == GlobalValue::ExternalWeakLinkage)
322 Linkage = GlobalValue::LinkOnceAnyLinkage;
323 else if (Linkage == GlobalValue::AvailableExternallyLinkage)
324 Linkage = GlobalValue::LinkOnceODRLinkage;
325 else if (Linkage == GlobalValue::InternalLinkage ||
326 Linkage == GlobalValue::ExternalLinkage)
327 Linkage = GlobalValue::PrivateLinkage;
328
329 auto *Value =
330 ConstantDataArray::getString(M.getContext(), PGOFuncName, false);
331 auto FuncNameVar =
332 new GlobalVariable(M, Value->getType(), true, Linkage, Value,
333 getPGOFuncNameVarName(PGOFuncName, Linkage));
334
335 // Hide the symbol so that we correctly get a copy for each executable.
336 if (!GlobalValue::isLocalLinkage(FuncNameVar->getLinkage()))
337 FuncNameVar->setVisibility(GlobalValue::HiddenVisibility);
338
339 return FuncNameVar;
340}
341
342GlobalVariable *createPGOFuncNameVar(Function &F, StringRef PGOFuncName) {
343 return createPGOFuncNameVar(*F.getParent(), F.getLinkage(), PGOFuncName);
344}
345
346Error InstrProfSymtab::create(Module &M, bool InLTO) {
347 for (Function &F : M) {
348 // Function may not have a name: like using asm("") to overwrite the name.
349 // Ignore in this case.
350 if (!F.hasName())
351 continue;
352 const std::string &PGOFuncName = getPGOFuncName(F, InLTO);
353 if (Error E = addFuncName(PGOFuncName))
354 return E;
355 MD5FuncMap.emplace_back(Function::getGUID(PGOFuncName), &F);
356 // In ThinLTO, local function may have been promoted to global and have
357 // suffix ".llvm." added to the function name. We need to add the
358 // stripped function name to the symbol table so that we can find a match
359 // from profile.
360 //
361 // We may have other suffixes similar as ".llvm." which are needed to
362 // be stripped before the matching, but ".__uniq." suffix which is used
363 // to differentiate internal linkage functions in different modules
364 // should be kept. Now this is the only suffix with the pattern ".xxx"
365 // which is kept before matching.
366 const std::string UniqSuffix = ".__uniq.";
367 auto pos = PGOFuncName.find(UniqSuffix);
368 // Search '.' after ".__uniq." if ".__uniq." exists, otherwise
369 // search '.' from the beginning.
370 if (pos != std::string::npos)
371 pos += UniqSuffix.length();
372 else
373 pos = 0;
374 pos = PGOFuncName.find('.', pos);
375 if (pos != std::string::npos && pos != 0) {
376 const std::string &OtherFuncName = PGOFuncName.substr(0, pos);
377 if (Error E = addFuncName(OtherFuncName))
378 return E;
379 MD5FuncMap.emplace_back(Function::getGUID(OtherFuncName), &F);
380 }
381 }
382 Sorted = false;
383 finalizeSymtab();
384 return Error::success();
385}
386
387uint64_t InstrProfSymtab::getFunctionHashFromAddress(uint64_t Address) {
388 finalizeSymtab();
389 auto It = partition_point(AddrToMD5Map, [=](std::pair<uint64_t, uint64_t> A) {
390 return A.first < Address;
391 });
392 // Raw function pointer collected by value profiler may be from
393 // external functions that are not instrumented. They won't have
394 // mapping data to be used by the deserializer. Force the value to
395 // be 0 in this case.
396 if (It != AddrToMD5Map.end() && It->first == Address)
397 return (uint64_t)It->second;
398 return 0;
399}
400
401Error collectPGOFuncNameStrings(ArrayRef<std::string> NameStrs,
402 bool doCompression, std::string &Result) {
403 assert(!NameStrs.empty() && "No name data to emit")((void)0);
404
405 uint8_t Header[16], *P = Header;
406 std::string UncompressedNameStrings =
407 join(NameStrs.begin(), NameStrs.end(), getInstrProfNameSeparator());
408
409 assert(StringRef(UncompressedNameStrings)((void)0)
410 .count(getInstrProfNameSeparator()) == (NameStrs.size() - 1) &&((void)0)
411 "PGO name is invalid (contains separator token)")((void)0);
412
413 unsigned EncLen = encodeULEB128(UncompressedNameStrings.length(), P);
414 P += EncLen;
415
416 auto WriteStringToResult = [&](size_t CompressedLen, StringRef InputStr) {
417 EncLen = encodeULEB128(CompressedLen, P);
418 P += EncLen;
419 char *HeaderStr = reinterpret_cast<char *>(&Header[0]);
420 unsigned HeaderLen = P - &Header[0];
421 Result.append(HeaderStr, HeaderLen);
422 Result += InputStr;
423 return Error::success();
424 };
425
426 if (!doCompression) {
427 return WriteStringToResult(0, UncompressedNameStrings);
428 }
429
430 SmallString<128> CompressedNameStrings;
431 Error E = zlib::compress(StringRef(UncompressedNameStrings),
432 CompressedNameStrings, zlib::BestSizeCompression);
433 if (E) {
434 consumeError(std::move(E));
435 return make_error<InstrProfError>(instrprof_error::compress_failed);
436 }
437
438 return WriteStringToResult(CompressedNameStrings.size(),
439 CompressedNameStrings);
440}
441
442StringRef getPGOFuncNameVarInitializer(GlobalVariable *NameVar) {
443 auto *Arr = cast<ConstantDataArray>(NameVar->getInitializer());
444 StringRef NameStr =
445 Arr->isCString() ? Arr->getAsCString() : Arr->getAsString();
446 return NameStr;
447}
448
449Error collectPGOFuncNameStrings(ArrayRef<GlobalVariable *> NameVars,
450 std::string &Result, bool doCompression) {
451 std::vector<std::string> NameStrs;
452 for (auto *NameVar : NameVars) {
453 NameStrs.push_back(std::string(getPGOFuncNameVarInitializer(NameVar)));
454 }
455 return collectPGOFuncNameStrings(
456 NameStrs, zlib::isAvailable() && doCompression, Result);
457}
458
459Error readPGOFuncNameStrings(StringRef NameStrings, InstrProfSymtab &Symtab) {
460 const uint8_t *P = NameStrings.bytes_begin();
461 const uint8_t *EndP = NameStrings.bytes_end();
462 while (P < EndP) {
1
Assuming 'P' is < 'EndP'
→
2
←
Loop condition is true. Entering loop body
→
463 uint32_t N;
464 uint64_t UncompressedSize = decodeULEB128(P, &N);
3
←
Calling 'decodeULEB128'
→
10
←
Returning from 'decodeULEB128'
→
11
←
'UncompressedSize' initialized to 0
→
465 P += N;
466 uint64_t CompressedSize = decodeULEB128(P, &N);
467 P += N;
468 bool isCompressed = (CompressedSize != 0);
469 SmallString<128> UncompressedNameStrings;
470 StringRef NameStrings;
471 if (isCompressed
11.1
'isCompressed' is false
11.1
'isCompressed' is false
) {
12
←
Taking false branch
→
472 if (!llvm::zlib::isAvailable())
473 return make_error<InstrProfError>(instrprof_error::zlib_unavailable);
474
475 StringRef CompressedNameStrings(reinterpret_cast<const char *>(P),
476 CompressedSize);
477 if (Error E =
478 zlib::uncompress(CompressedNameStrings, UncompressedNameStrings,
479 UncompressedSize)) {
480 consumeError(std::move(E));
481 return make_error<InstrProfError>(instrprof_error::uncompress_failed);
482 }
483 P += CompressedSize;
484 NameStrings = StringRef(UncompressedNameStrings.data(),
485 UncompressedNameStrings.size());
486 } else {
487 NameStrings =
488 StringRef(reinterpret_cast<const char *>(P), UncompressedSize);
489 P += UncompressedSize;
13
←
Null pointer value stored to 'P'
→
490 }
491 // Now parse the name strings.
492 SmallVector<StringRef, 0> Names;
493 NameStrings.split(Names, getInstrProfNameSeparator());
494 for (StringRef &Name : Names)
14
←
Assuming '__begin2' is equal to '__end2'
→
495 if (Error E = Symtab.addFuncName(Name))
496 return E;
497
498 while (P
14.1
'P' is < 'EndP'
14.1
'P' is < 'EndP'
 < EndP && *P == 0)
15
←
Dereference of null pointer (loaded from variable 'P')
499 P++;
500 }
501 return Error::success();
502}
503
504void InstrProfRecord::accumulateCounts(CountSumOrPercent &Sum) const {
505 uint64_t FuncSum = 0;
506 Sum.NumEntries += Counts.size();
507 for (size_t F = 0, E = Counts.size(); F < E; ++F)
508 FuncSum += Counts[F];
509 Sum.CountSum += FuncSum;
510
511 for (uint32_t VK = IPVK_First; VK <= IPVK_Last; ++VK) {
512 uint64_t KindSum = 0;
513 uint32_t NumValueSites = getNumValueSites(VK);
514 for (size_t I = 0; I < NumValueSites; ++I) {
515 uint32_t NV = getNumValueDataForSite(VK, I);
516 std::unique_ptr<InstrProfValueData[]> VD = getValueForSite(VK, I);
517 for (uint32_t V = 0; V < NV; V++)
518 KindSum += VD[V].Count;
519 }
520 Sum.ValueCounts[VK] += KindSum;
521 }
522}
523
524void InstrProfValueSiteRecord::overlap(InstrProfValueSiteRecord &Input,
525 uint32_t ValueKind,
526 OverlapStats &Overlap,
527 OverlapStats &FuncLevelOverlap) {
528 this->sortByTargetValues();
529 Input.sortByTargetValues();
530 double Score = 0.0f, FuncLevelScore = 0.0f;
531 auto I = ValueData.begin();
532 auto IE = ValueData.end();
533 auto J = Input.ValueData.begin();
534 auto JE = Input.ValueData.end();
535 while (I != IE && J != JE) {
536 if (I->Value == J->Value) {
537 Score += OverlapStats::score(I->Count, J->Count,
538 Overlap.Base.ValueCounts[ValueKind],
539 Overlap.Test.ValueCounts[ValueKind]);
540 FuncLevelScore += OverlapStats::score(
541 I->Count, J->Count, FuncLevelOverlap.Base.ValueCounts[ValueKind],
542 FuncLevelOverlap.Test.ValueCounts[ValueKind]);
543 ++I;
544 } else if (I->Value < J->Value) {
545 ++I;
546 continue;
547 }
548 ++J;
549 }
550 Overlap.Overlap.ValueCounts[ValueKind] += Score;
551 FuncLevelOverlap.Overlap.ValueCounts[ValueKind] += FuncLevelScore;
552}
553
554// Return false on mismatch.
555void InstrProfRecord::overlapValueProfData(uint32_t ValueKind,
556 InstrProfRecord &Other,
557 OverlapStats &Overlap,
558 OverlapStats &FuncLevelOverlap) {
559 uint32_t ThisNumValueSites = getNumValueSites(ValueKind);
560 assert(ThisNumValueSites == Other.getNumValueSites(ValueKind))((void)0);
561 if (!ThisNumValueSites)
562 return;
563
564 std::vector<InstrProfValueSiteRecord> &ThisSiteRecords =
565 getOrCreateValueSitesForKind(ValueKind);
566 MutableArrayRef<InstrProfValueSiteRecord> OtherSiteRecords =
567 Other.getValueSitesForKind(ValueKind);
568 for (uint32_t I = 0; I < ThisNumValueSites; I++)
569 ThisSiteRecords[I].overlap(OtherSiteRecords[I], ValueKind, Overlap,
570 FuncLevelOverlap);
571}
572
573void InstrProfRecord::overlap(InstrProfRecord &Other, OverlapStats &Overlap,
574 OverlapStats &FuncLevelOverlap,
575 uint64_t ValueCutoff) {
576 // FuncLevel CountSum for other should already computed and nonzero.
577 assert(FuncLevelOverlap.Test.CountSum >= 1.0f)((void)0);
578 accumulateCounts(FuncLevelOverlap.Base);
579 bool Mismatch = (Counts.size() != Other.Counts.size());
580
581 // Check if the value profiles mismatch.
582 if (!Mismatch) {
583 for (uint32_t Kind = IPVK_First; Kind <= IPVK_Last; ++Kind) {
584 uint32_t ThisNumValueSites = getNumValueSites(Kind);
585 uint32_t OtherNumValueSites = Other.getNumValueSites(Kind);
586 if (ThisNumValueSites != OtherNumValueSites) {
587 Mismatch = true;
588 break;
589 }
590 }
591 }
592 if (Mismatch) {
593 Overlap.addOneMismatch(FuncLevelOverlap.Test);
594 return;
595 }
596
597 // Compute overlap for value counts.
598 for (uint32_t Kind = IPVK_First; Kind <= IPVK_Last; ++Kind)
599 overlapValueProfData(Kind, Other, Overlap, FuncLevelOverlap);
600
601 double Score = 0.0;
602 uint64_t MaxCount = 0;
603 // Compute overlap for edge counts.
604 for (size_t I = 0, E = Other.Counts.size(); I < E; ++I) {
605 Score += OverlapStats::score(Counts[I], Other.Counts[I],
606 Overlap.Base.CountSum, Overlap.Test.CountSum);
607 MaxCount = std::max(Other.Counts[I], MaxCount);
608 }
609 Overlap.Overlap.CountSum += Score;
610 Overlap.Overlap.NumEntries += 1;
611
612 if (MaxCount >= ValueCutoff) {
613 double FuncScore = 0.0;
614 for (size_t I = 0, E = Other.Counts.size(); I < E; ++I)
615 FuncScore += OverlapStats::score(Counts[I], Other.Counts[I],
616 FuncLevelOverlap.Base.CountSum,
617 FuncLevelOverlap.Test.CountSum);
618 FuncLevelOverlap.Overlap.CountSum = FuncScore;
619 FuncLevelOverlap.Overlap.NumEntries = Other.Counts.size();
620 FuncLevelOverlap.Valid = true;
621 }
622}
623
624void InstrProfValueSiteRecord::merge(InstrProfValueSiteRecord &Input,
625 uint64_t Weight,
626 function_ref<void(instrprof_error)> Warn) {
627 this->sortByTargetValues();
628 Input.sortByTargetValues();
629 auto I = ValueData.begin();
630 auto IE = ValueData.end();
631 for (auto J = Input.ValueData.begin(), JE = Input.ValueData.end(); J != JE;
632 ++J) {
633 while (I != IE && I->Value < J->Value)
634 ++I;
635 if (I != IE && I->Value == J->Value) {
636 bool Overflowed;
637 I->Count = SaturatingMultiplyAdd(J->Count, Weight, I->Count, &Overflowed);
638 if (Overflowed)
639 Warn(instrprof_error::counter_overflow);
640 ++I;
641 continue;
642 }
643 ValueData.insert(I, *J);
644 }
645}
646
647void InstrProfValueSiteRecord::scale(uint64_t N, uint64_t D,
648 function_ref<void(instrprof_error)> Warn) {
649 for (auto I = ValueData.begin(), IE = ValueData.end(); I != IE; ++I) {
650 bool Overflowed;
651 I->Count = SaturatingMultiply(I->Count, N, &Overflowed) / D;
652 if (Overflowed)
653 Warn(instrprof_error::counter_overflow);
654 }
655}
656
657// Merge Value Profile data from Src record to this record for ValueKind.
658// Scale merged value counts by \p Weight.
659void InstrProfRecord::mergeValueProfData(
660 uint32_t ValueKind, InstrProfRecord &Src, uint64_t Weight,
661 function_ref<void(instrprof_error)> Warn) {
662 uint32_t ThisNumValueSites = getNumValueSites(ValueKind);
663 uint32_t OtherNumValueSites = Src.getNumValueSites(ValueKind);
664 if (ThisNumValueSites != OtherNumValueSites) {
665 Warn(instrprof_error::value_site_count_mismatch);
666 return;
667 }
668 if (!ThisNumValueSites)
669 return;
670 std::vector<InstrProfValueSiteRecord> &ThisSiteRecords =
671 getOrCreateValueSitesForKind(ValueKind);
672 MutableArrayRef<InstrProfValueSiteRecord> OtherSiteRecords =
673 Src.getValueSitesForKind(ValueKind);
674 for (uint32_t I = 0; I < ThisNumValueSites; I++)
675 ThisSiteRecords[I].merge(OtherSiteRecords[I], Weight, Warn);
676}
677
678void InstrProfRecord::merge(InstrProfRecord &Other, uint64_t Weight,
679 function_ref<void(instrprof_error)> Warn) {
680 // If the number of counters doesn't match we either have bad data
681 // or a hash collision.
682 if (Counts.size() != Other.Counts.size()) {
683 Warn(instrprof_error::count_mismatch);
684 return;
685 }
686
687 for (size_t I = 0, E = Other.Counts.size(); I < E; ++I) {
688 bool Overflowed;
689 Counts[I] =
690 SaturatingMultiplyAdd(Other.Counts[I], Weight, Counts[I], &Overflowed);
691 if (Overflowed)
692 Warn(instrprof_error::counter_overflow);
693 }
694
695 for (uint32_t Kind = IPVK_First; Kind <= IPVK_Last; ++Kind)
696 mergeValueProfData(Kind, Other, Weight, Warn);
697}
698
699void InstrProfRecord::scaleValueProfData(
700 uint32_t ValueKind, uint64_t N, uint64_t D,
701 function_ref<void(instrprof_error)> Warn) {
702 for (auto &R : getValueSitesForKind(ValueKind))
703 R.scale(N, D, Warn);
704}
705
706void InstrProfRecord::scale(uint64_t N, uint64_t D,
707 function_ref<void(instrprof_error)> Warn) {
708 assert(D != 0 && "D cannot be 0")((void)0);
709 for (auto &Count : this->Counts) {
710 bool Overflowed;
711 Count = SaturatingMultiply(Count, N, &Overflowed) / D;
712 if (Overflowed)
713 Warn(instrprof_error::counter_overflow);
714 }
715 for (uint32_t Kind = IPVK_First; Kind <= IPVK_Last; ++Kind)
716 scaleValueProfData(Kind, N, D, Warn);
717}
718
719// Map indirect call target name hash to name string.
720uint64_t InstrProfRecord::remapValue(uint64_t Value, uint32_t ValueKind,
721 InstrProfSymtab *SymTab) {
722 if (!SymTab)
723 return Value;
724
725 if (ValueKind == IPVK_IndirectCallTarget)
726 return SymTab->getFunctionHashFromAddress(Value);
727
728 return Value;
729}
730
731void InstrProfRecord::addValueData(uint32_t ValueKind, uint32_t Site,
732 InstrProfValueData *VData, uint32_t N,
733 InstrProfSymtab *ValueMap) {
734 for (uint32_t I = 0; I < N; I++) {
735 VData[I].Value = remapValue(VData[I].Value, ValueKind, ValueMap);
736 }
737 std::vector<InstrProfValueSiteRecord> &ValueSites =
738 getOrCreateValueSitesForKind(ValueKind);
739 if (N == 0)
740 ValueSites.emplace_back();
741 else
742 ValueSites.emplace_back(VData, VData + N);
743}
744
745#define INSTR_PROF_COMMON_API_IMPL
746#include "llvm/ProfileData/InstrProfData.inc"
747
748/*!
749 * ValueProfRecordClosure Interface implementation for InstrProfRecord
750 * class. These C wrappers are used as adaptors so that C++ code can be
751 * invoked as callbacks.
752 */
753uint32_t getNumValueKindsInstrProf(const void *Record) {
754 return reinterpret_cast<const InstrProfRecord *>(Record)->getNumValueKinds();
755}
756
757uint32_t getNumValueSitesInstrProf(const void *Record, uint32_t VKind) {
758 return reinterpret_cast<const InstrProfRecord *>(Record)
759 ->getNumValueSites(VKind);
760}
761
762uint32_t getNumValueDataInstrProf(const void *Record, uint32_t VKind) {
763 return reinterpret_cast<const InstrProfRecord *>(Record)
764 ->getNumValueData(VKind);
765}
766
767uint32_t getNumValueDataForSiteInstrProf(const void *R, uint32_t VK,
768 uint32_t S) {
769 return reinterpret_cast<const InstrProfRecord *>(R)
770 ->getNumValueDataForSite(VK, S);
771}
772
773void getValueForSiteInstrProf(const void *R, InstrProfValueData *Dst,
774 uint32_t K, uint32_t S) {
775 reinterpret_cast<const InstrProfRecord *>(R)->getValueForSite(Dst, K, S);
776}
777
778ValueProfData *allocValueProfDataInstrProf(size_t TotalSizeInBytes) {
779 ValueProfData *VD =
780 (ValueProfData *)(new (::operator new(TotalSizeInBytes)) ValueProfData());
781 memset(VD, 0, TotalSizeInBytes);
782 return VD;
783}
784
785static ValueProfRecordClosure InstrProfRecordClosure = {
786 nullptr,
787 getNumValueKindsInstrProf,
788 getNumValueSitesInstrProf,
789 getNumValueDataInstrProf,
790 getNumValueDataForSiteInstrProf,
791 nullptr,
792 getValueForSiteInstrProf,
793 allocValueProfDataInstrProf};
794
795// Wrapper implementation using the closure mechanism.
796uint32_t ValueProfData::getSize(const InstrProfRecord &Record) {
797 auto Closure = InstrProfRecordClosure;
798 Closure.Record = &Record;
799 return getValueProfDataSize(&Closure);
800}
801
802// Wrapper implementation using the closure mechanism.
803std::unique_ptr<ValueProfData>
804ValueProfData::serializeFrom(const InstrProfRecord &Record) {
805 InstrProfRecordClosure.Record = &Record;
806
807 std::unique_ptr<ValueProfData> VPD(
808 serializeValueProfDataFrom(&InstrProfRecordClosure, nullptr));
809 return VPD;
810}
811
812void ValueProfRecord::deserializeTo(InstrProfRecord &Record,
813 InstrProfSymtab *SymTab) {
814 Record.reserveSites(Kind, NumValueSites);
815
816 InstrProfValueData *ValueData = getValueProfRecordValueData(this);
817 for (uint64_t VSite = 0; VSite < NumValueSites; ++VSite) {
818 uint8_t ValueDataCount = this->SiteCountArray[VSite];
819 Record.addValueData(Kind, VSite, ValueData, ValueDataCount, SymTab);
820 ValueData += ValueDataCount;
821 }
822}
823
824// For writing/serializing, Old is the host endianness, and New is
825// byte order intended on disk. For Reading/deserialization, Old
826// is the on-disk source endianness, and New is the host endianness.
827void ValueProfRecord::swapBytes(support::endianness Old,
828 support::endianness New) {
829 using namespace support;
830
831 if (Old == New)
832 return;
833
834 if (getHostEndianness() != Old) {
835 sys::swapByteOrder<uint32_t>(NumValueSites);
836 sys::swapByteOrder<uint32_t>(Kind);
837 }
838 uint32_t ND = getValueProfRecordNumValueData(this);
839 InstrProfValueData *VD = getValueProfRecordValueData(this);
840
841 // No need to swap byte array: SiteCountArrray.
842 for (uint32_t I = 0; I < ND; I++) {
843 sys::swapByteOrder<uint64_t>(VD[I].Value);
844 sys::swapByteOrder<uint64_t>(VD[I].Count);
845 }
846 if (getHostEndianness() == Old) {
847 sys::swapByteOrder<uint32_t>(NumValueSites);
848 sys::swapByteOrder<uint32_t>(Kind);
849 }
850}
851
852void ValueProfData::deserializeTo(InstrProfRecord &Record,
853 InstrProfSymtab *SymTab) {
854 if (NumValueKinds == 0)
855 return;
856
857 ValueProfRecord *VR = getFirstValueProfRecord(this);
858 for (uint32_t K = 0; K < NumValueKinds; K++) {
859 VR->deserializeTo(Record, SymTab);
860 VR = getValueProfRecordNext(VR);
861 }
862}
863
864template <class T>
865static T swapToHostOrder(const unsigned char *&D, support::endianness Orig) {
866 using namespace support;
867
868 if (Orig == little)
869 return endian::readNext<T, little, unaligned>(D);
870 else
871 return endian::readNext<T, big, unaligned>(D);
872}
873
874static std::unique_ptr<ValueProfData> allocValueProfData(uint32_t TotalSize) {
875 return std::unique_ptr<ValueProfData>(new (::operator new(TotalSize))
876 ValueProfData());
877}
878
879Error ValueProfData::checkIntegrity() {
880 if (NumValueKinds > IPVK_Last + 1)
881 return make_error<InstrProfError>(instrprof_error::malformed);
882 // Total size needs to be mulltiple of quadword size.
883 if (TotalSize % sizeof(uint64_t))
884 return make_error<InstrProfError>(instrprof_error::malformed);
885
886 ValueProfRecord *VR = getFirstValueProfRecord(this);
887 for (uint32_t K = 0; K < this->NumValueKinds; K++) {
888 if (VR->Kind > IPVK_Last)
889 return make_error<InstrProfError>(instrprof_error::malformed);
890 VR = getValueProfRecordNext(VR);
891 if ((char *)VR - (char *)this > (ptrdiff_t)TotalSize)
892 return make_error<InstrProfError>(instrprof_error::malformed);
893 }
894 return Error::success();
895}
896
897Expected<std::unique_ptr<ValueProfData>>
898ValueProfData::getValueProfData(const unsigned char *D,
899 const unsigned char *const BufferEnd,
900 support::endianness Endianness) {
901 using namespace support;
902
903 if (D + sizeof(ValueProfData) > BufferEnd)
904 return make_error<InstrProfError>(instrprof_error::truncated);
905
906 const unsigned char *Header = D;
907 uint32_t TotalSize = swapToHostOrder<uint32_t>(Header, Endianness);
908 if (D + TotalSize > BufferEnd)
909 return make_error<InstrProfError>(instrprof_error::too_large);
910
911 std::unique_ptr<ValueProfData> VPD = allocValueProfData(TotalSize);
912 memcpy(VPD.get(), D, TotalSize);
913 // Byte swap.
914 VPD->swapBytesToHost(Endianness);
915
916 Error E = VPD->checkIntegrity();
917 if (E)
918 return std::move(E);
919
920 return std::move(VPD);
921}
922
923void ValueProfData::swapBytesToHost(support::endianness Endianness) {
924 using namespace support;
925
926 if (Endianness == getHostEndianness())
927 return;
928
929 sys::swapByteOrder<uint32_t>(TotalSize);
930 sys::swapByteOrder<uint32_t>(NumValueKinds);
931
932 ValueProfRecord *VR = getFirstValueProfRecord(this);
933 for (uint32_t K = 0; K < NumValueKinds; K++) {
934 VR->swapBytes(Endianness, getHostEndianness());
935 VR = getValueProfRecordNext(VR);
936 }
937}
938
939void ValueProfData::swapBytesFromHost(support::endianness Endianness) {
940 using namespace support;
941
942 if (Endianness == getHostEndianness())
943 return;
944
945 ValueProfRecord *VR = getFirstValueProfRecord(this);
946 for (uint32_t K = 0; K < NumValueKinds; K++) {
947 ValueProfRecord *NVR = getValueProfRecordNext(VR);
948 VR->swapBytes(getHostEndianness(), Endianness);
949 VR = NVR;
950 }
951 sys::swapByteOrder<uint32_t>(TotalSize);
952 sys::swapByteOrder<uint32_t>(NumValueKinds);
953}
954
955void annotateValueSite(Module &M, Instruction &Inst,
956 const InstrProfRecord &InstrProfR,
957 InstrProfValueKind ValueKind, uint32_t SiteIdx,
958 uint32_t MaxMDCount) {
959 uint32_t NV = InstrProfR.getNumValueDataForSite(ValueKind, SiteIdx);
960 if (!NV)
961 return;
962
963 uint64_t Sum = 0;
964 std::unique_ptr<InstrProfValueData[]> VD =
965 InstrProfR.getValueForSite(ValueKind, SiteIdx, &Sum);
966
967 ArrayRef<InstrProfValueData> VDs(VD.get(), NV);
968 annotateValueSite(M, Inst, VDs, Sum, ValueKind, MaxMDCount);
969}
970
971void annotateValueSite(Module &M, Instruction &Inst,
972 ArrayRef<InstrProfValueData> VDs,
973 uint64_t Sum, InstrProfValueKind ValueKind,
974 uint32_t MaxMDCount) {
975 LLVMContext &Ctx = M.getContext();
976 MDBuilder MDHelper(Ctx);
977 SmallVector<Metadata *, 3> Vals;
978 // Tag
979 Vals.push_back(MDHelper.createString("VP"));
980 // Value Kind
981 Vals.push_back(MDHelper.createConstant(
982 ConstantInt::get(Type::getInt32Ty(Ctx), ValueKind)));
983 // Total Count
984 Vals.push_back(
985 MDHelper.createConstant(ConstantInt::get(Type::getInt64Ty(Ctx), Sum)));
986
987 // Value Profile Data
988 uint32_t MDCount = MaxMDCount;
989 for (auto &VD : VDs) {
990 Vals.push_back(MDHelper.createConstant(
991 ConstantInt::get(Type::getInt64Ty(Ctx), VD.Value)));
992 Vals.push_back(MDHelper.createConstant(
993 ConstantInt::get(Type::getInt64Ty(Ctx), VD.Count)));
994 if (--MDCount == 0)
995 break;
996 }
997 Inst.setMetadata(LLVMContext::MD_prof, MDNode::get(Ctx, Vals));
998}
999
1000bool getValueProfDataFromInst(const Instruction &Inst,
1001 InstrProfValueKind ValueKind,
1002 uint32_t MaxNumValueData,
1003 InstrProfValueData ValueData[],
1004 uint32_t &ActualNumValueData, uint64_t &TotalC,
1005 bool GetNoICPValue) {
1006 MDNode *MD = Inst.getMetadata(LLVMContext::MD_prof);
1007 if (!MD)
1008 return false;
1009
1010 unsigned NOps = MD->getNumOperands();
1011
1012 if (NOps < 5)
1013 return false;
1014
1015 // Operand 0 is a string tag "VP":
1016 MDString *Tag = cast<MDString>(MD->getOperand(0));
1017 if (!Tag)
1018 return false;
1019
1020 if (!Tag->getString().equals("VP"))
1021 return false;
1022
1023 // Now check kind:
1024 ConstantInt *KindInt = mdconst::dyn_extract<ConstantInt>(MD->getOperand(1));
1025 if (!KindInt)
1026 return false;
1027 if (KindInt->getZExtValue() != ValueKind)
1028 return false;
1029
1030 // Get total count
1031 ConstantInt *TotalCInt = mdconst::dyn_extract<ConstantInt>(MD->getOperand(2));
1032 if (!TotalCInt)
1033 return false;
1034 TotalC = TotalCInt->getZExtValue();
1035
1036 ActualNumValueData = 0;
1037
1038 for (unsigned I = 3; I < NOps; I += 2) {
1039 if (ActualNumValueData >= MaxNumValueData)
1040 break;
1041 ConstantInt *Value = mdconst::dyn_extract<ConstantInt>(MD->getOperand(I));
1042 ConstantInt *Count =
1043 mdconst::dyn_extract<ConstantInt>(MD->getOperand(I + 1));
1044 if (!Value || !Count)
1045 return false;
1046 uint64_t CntValue = Count->getZExtValue();
1047 if (!GetNoICPValue && (CntValue == NOMORE_ICP_MAGICNUM))
1048 continue;
1049 ValueData[ActualNumValueData].Value = Value->getZExtValue();
1050 ValueData[ActualNumValueData].Count = CntValue;
1051 ActualNumValueData++;
1052 }
1053 return true;
1054}
1055
1056MDNode *getPGOFuncNameMetadata(const Function &F) {
1057 return F.getMetadata(getPGOFuncNameMetadataName());
1058}
1059
1060void createPGOFuncNameMetadata(Function &F, StringRef PGOFuncName) {
1061 // Only for internal linkage functions.
1062 if (PGOFuncName == F.getName())
1063 return;
1064 // Don't create duplicated meta-data.
1065 if (getPGOFuncNameMetadata(F))
1066 return;
1067 LLVMContext &C = F.getContext();
1068 MDNode *N = MDNode::get(C, MDString::get(C, PGOFuncName));
1069 F.setMetadata(getPGOFuncNameMetadataName(), N);
1070}
1071
1072bool needsComdatForCounter(const Function &F, const Module &M) {
1073 if (F.hasComdat())
1074 return true;
1075
1076 if (!Triple(M.getTargetTriple()).supportsCOMDAT())
1077 return false;
1078
1079 // See createPGOFuncNameVar for more details. To avoid link errors, profile
1080 // counters for function with available_externally linkage needs to be changed
1081 // to linkonce linkage. On ELF based systems, this leads to weak symbols to be
1082 // created. Without using comdat, duplicate entries won't be removed by the
1083 // linker leading to increased data segement size and raw profile size. Even
1084 // worse, since the referenced counter from profile per-function data object
1085 // will be resolved to the common strong definition, the profile counts for
1086 // available_externally functions will end up being duplicated in raw profile
1087 // data. This can result in distorted profile as the counts of those dups
1088 // will be accumulated by the profile merger.
1089 GlobalValue::LinkageTypes Linkage = F.getLinkage();
1090 if (Linkage != GlobalValue::ExternalWeakLinkage &&
1091 Linkage != GlobalValue::AvailableExternallyLinkage)
1092 return false;
1093
1094 return true;
1095}
1096
1097// Check if INSTR_PROF_RAW_VERSION_VAR is defined.
1098bool isIRPGOFlagSet(const Module *M) {
1099 auto IRInstrVar =
1100 M->getNamedGlobal(INSTR_PROF_QUOTE(INSTR_PROF_RAW_VERSION_VAR)"__llvm_profile_raw_version");
1101 if (!IRInstrVar || IRInstrVar->isDeclaration() ||
1102 IRInstrVar->hasLocalLinkage())
1103 return false;
1104
1105 // Check if the flag is set.
1106 if (!IRInstrVar->hasInitializer())
1107 return false;
1108
1109 auto *InitVal = dyn_cast_or_null<ConstantInt>(IRInstrVar->getInitializer());
1110 if (!InitVal)
1111 return false;
1112 return (InitVal->getZExtValue() & VARIANT_MASK_IR_PROF(0x1ULL << 56)) != 0;
1113}
1114
1115// Check if we can safely rename this Comdat function.
1116bool canRenameComdatFunc(const Function &F, bool CheckAddressTaken) {
1117 if (F.getName().empty())
1118 return false;
1119 if (!needsComdatForCounter(F, *(F.getParent())))
1120 return false;
1121 // Unsafe to rename the address-taken function (which can be used in
1122 // function comparison).
1123 if (CheckAddressTaken && F.hasAddressTaken())
1124 return false;
1125 // Only safe to do if this function may be discarded if it is not used
1126 // in the compilation unit.
1127 if (!GlobalValue::isDiscardableIfUnused(F.getLinkage()))
1128 return false;
1129
1130 // For AvailableExternallyLinkage functions.
1131 if (!F.hasComdat()) {
1132 assert(F.getLinkage() == GlobalValue::AvailableExternallyLinkage)((void)0);
1133 return true;
1134 }
1135 return true;
1136}
1137
1138// Create a COMDAT variable INSTR_PROF_RAW_VERSION_VAR to make the runtime
1139// aware this is an ir_level profile so it can set the version flag.
1140void createIRLevelProfileFlagVar(Module &M, bool IsCS,
1141 bool InstrEntryBBEnabled) {
1142 const StringRef VarName(INSTR_PROF_QUOTE(INSTR_PROF_RAW_VERSION_VAR)"__llvm_profile_raw_version");
1143 Type *IntTy64 = Type::getInt64Ty(M.getContext());
1144 uint64_t ProfileVersion = (INSTR_PROF_RAW_VERSION7 | VARIANT_MASK_IR_PROF(0x1ULL << 56));
1145 if (IsCS)
1146 ProfileVersion |= VARIANT_MASK_CSIR_PROF(0x1ULL << 57);
1147 if (InstrEntryBBEnabled)
1148 ProfileVersion |= VARIANT_MASK_INSTR_ENTRY(0x1ULL << 58);
1149 auto IRLevelVersionVariable = new GlobalVariable(
1150 M, IntTy64, true, GlobalValue::WeakAnyLinkage,
1151 Constant::getIntegerValue(IntTy64, APInt(64, ProfileVersion)), VarName);
1152 IRLevelVersionVariable->setVisibility(GlobalValue::DefaultVisibility);
1153 Triple TT(M.getTargetTriple());
1154 if (TT.supportsCOMDAT()) {
1155 IRLevelVersionVariable->setLinkage(GlobalValue::ExternalLinkage);
1156 IRLevelVersionVariable->setComdat(M.getOrInsertComdat(VarName));
1157 }
1158}
1159
1160// Create the variable for the profile file name.
1161void createProfileFileNameVar(Module &M, StringRef InstrProfileOutput) {
1162 if (InstrProfileOutput.empty())
1163 return;
1164 Constant *ProfileNameConst =
1165 ConstantDataArray::getString(M.getContext(), InstrProfileOutput, true);
1166 GlobalVariable *ProfileNameVar = new GlobalVariable(
1167 M, ProfileNameConst->getType(), true, GlobalValue::WeakAnyLinkage,
1168 ProfileNameConst, INSTR_PROF_QUOTE(INSTR_PROF_PROFILE_NAME_VAR)"__llvm_profile_filename");
1169 Triple TT(M.getTargetTriple());
1170 if (TT.supportsCOMDAT()) {
1171 ProfileNameVar->setLinkage(GlobalValue::ExternalLinkage);
1172 ProfileNameVar->setComdat(M.getOrInsertComdat(
1173 StringRef(INSTR_PROF_QUOTE(INSTR_PROF_PROFILE_NAME_VAR)"__llvm_profile_filename")));
1174 }
1175}
1176
1177Error OverlapStats::accumulateCounts(const std::string &BaseFilename,
1178 const std::string &TestFilename,
1179 bool IsCS) {
1180 auto getProfileSum = [IsCS](const std::string &Filename,
1181 CountSumOrPercent &Sum) -> Error {
1182 auto ReaderOrErr = InstrProfReader::create(Filename);
1183 if (Error E = ReaderOrErr.takeError()) {
1184 return E;
1185 }
1186 auto Reader = std::move(ReaderOrErr.get());
1187 Reader->accumulateCounts(Sum, IsCS);
1188 return Error::success();
1189 };
1190 auto Ret = getProfileSum(BaseFilename, Base);
1191 if (Ret)
1192 return Ret;
1193 Ret = getProfileSum(TestFilename, Test);
1194 if (Ret)
1195 return Ret;
1196 this->BaseFilename = &BaseFilename;
1197 this->TestFilename = &TestFilename;
1198 Valid = true;
1199 return Error::success();
1200}
1201
1202void OverlapStats::addOneMismatch(const CountSumOrPercent &MismatchFunc) {
1203 Mismatch.NumEntries += 1;
1204 Mismatch.CountSum += MismatchFunc.CountSum / Test.CountSum;
1205 for (unsigned I = 0; I < IPVK_Last - IPVK_First + 1; I++) {
1206 if (Test.ValueCounts[I] >= 1.0f)
1207 Mismatch.ValueCounts[I] +=
1208 MismatchFunc.ValueCounts[I] / Test.ValueCounts[I];
1209 }
1210}
1211
1212void OverlapStats::addOneUnique(const CountSumOrPercent &UniqueFunc) {
1213 Unique.NumEntries += 1;
1214 Unique.CountSum += UniqueFunc.CountSum / Test.CountSum;
1215 for (unsigned I = 0; I < IPVK_Last - IPVK_First + 1; I++) {
1216 if (Test.ValueCounts[I] >= 1.0f)
1217 Unique.ValueCounts[I] += UniqueFunc.ValueCounts[I] / Test.ValueCounts[I];
1218 }
1219}
1220
1221void OverlapStats::dump(raw_fd_ostream &OS) const {
1222 if (!Valid)
1223 return;
1224
1225 const char *EntryName =
1226 (Level == ProgramLevel ? "functions" : "edge counters");
1227 if (Level == ProgramLevel) {
1228 OS << "Profile overlap infomation for base_profile: " << *BaseFilename
1229 << " and test_profile: " << *TestFilename << "\nProgram level:\n";
1230 } else {
1231 OS << "Function level:\n"
1232 << " Function: " << FuncName << " (Hash=" << FuncHash << ")\n";
1233 }
1234
1235 OS << " # of " << EntryName << " overlap: " << Overlap.NumEntries << "\n";
1236 if (Mismatch.NumEntries)
1237 OS << " # of " << EntryName << " mismatch: " << Mismatch.NumEntries
1238 << "\n";
1239 if (Unique.NumEntries)
1240 OS << " # of " << EntryName
1241 << " only in test_profile: " << Unique.NumEntries << "\n";
1242
1243 OS << " Edge profile overlap: " << format("%.3f%%", Overlap.CountSum * 100)
1244 << "\n";
1245 if (Mismatch.NumEntries)
1246 OS << " Mismatched count percentage (Edge): "
1247 << format("%.3f%%", Mismatch.CountSum * 100) << "\n";
1248 if (Unique.NumEntries)
1249 OS << " Percentage of Edge profile only in test_profile: "
1250 << format("%.3f%%", Unique.CountSum * 100) << "\n";
1251 OS << " Edge profile base count sum: " << format("%.0f", Base.CountSum)
1252 << "\n"
1253 << " Edge profile test count sum: " << format("%.0f", Test.CountSum)
1254 << "\n";
1255
1256 for (unsigned I = 0; I < IPVK_Last - IPVK_First + 1; I++) {
1257 if (Base.ValueCounts[I] < 1.0f && Test.ValueCounts[I] < 1.0f)
1258 continue;
1259 char ProfileKindName[20];
1260 switch (I) {
1261 case IPVK_IndirectCallTarget:
1262 strncpy(ProfileKindName, "IndirectCall", 19);
1263 break;
1264 case IPVK_MemOPSize:
1265 strncpy(ProfileKindName, "MemOP", 19);
1266 break;
1267 default:
1268 snprintf(ProfileKindName, 19, "VP[%d]", I);
1269 break;
1270 }
1271 OS << " " << ProfileKindName
1272 << " profile overlap: " << format("%.3f%%", Overlap.ValueCounts[I] * 100)
1273 << "\n";
1274 if (Mismatch.NumEntries)
1275 OS << " Mismatched count percentage (" << ProfileKindName
1276 << "): " << format("%.3f%%", Mismatch.ValueCounts[I] * 100) << "\n";
1277 if (Unique.NumEntries)
1278 OS << " Percentage of " << ProfileKindName
1279 << " profile only in test_profile: "
1280 << format("%.3f%%", Unique.ValueCounts[I] * 100) << "\n";
1281 OS << " " << ProfileKindName
1282 << " profile base count sum: " << format("%.0f", Base.ValueCounts[I])
1283 << "\n"
1284 << " " << ProfileKindName
1285 << " profile test count sum: " << format("%.0f", Test.ValueCounts[I])
1286 << "\n";
1287 }
1288}
1289
1290} // end namespace llvm
←

/usr/src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/include/llvm/Support/LEB128.h

1//===- llvm/Support/LEB128.h - [SU]LEB128 utility functions -----*- 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 declares some utility functions for encoding SLEB128 and
10// ULEB128 values.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_SUPPORT_LEB128_H
15#define LLVM_SUPPORT_LEB128_H
16
17#include "llvm/Support/raw_ostream.h"
18
19namespace llvm {
20
21/// Utility function to encode a SLEB128 value to an output stream. Returns
22/// the length in bytes of the encoded value.
23inline unsigned encodeSLEB128(int64_t Value, raw_ostream &OS,
24 unsigned PadTo = 0) {
25 bool More;
26 unsigned Count = 0;
27 do {
28 uint8_t Byte = Value & 0x7f;
29 // NOTE: this assumes that this signed shift is an arithmetic right shift.
30 Value >>= 7;
31 More = !((((Value == 0 ) && ((Byte & 0x40) == 0)) ||
32 ((Value == -1) && ((Byte & 0x40) != 0))));
33 Count++;
34 if (More || Count < PadTo)
35 Byte |= 0x80; // Mark this byte to show that more bytes will follow.
36 OS << char(Byte);
37 } while (More);
38
39 // Pad with 0x80 and emit a terminating byte at the end.
40 if (Count < PadTo) {
41 uint8_t PadValue = Value < 0 ? 0x7f : 0x00;
42 for (; Count < PadTo - 1; ++Count)
43 OS << char(PadValue | 0x80);
44 OS << char(PadValue);
45 Count++;
46 }
47 return Count;
48}
49
50/// Utility function to encode a SLEB128 value to a buffer. Returns
51/// the length in bytes of the encoded value.
52inline unsigned encodeSLEB128(int64_t Value, uint8_t *p, unsigned PadTo = 0) {
53 uint8_t *orig_p = p;
54 unsigned Count = 0;
55 bool More;
56 do {
57 uint8_t Byte = Value & 0x7f;
58 // NOTE: this assumes that this signed shift is an arithmetic right shift.
59 Value >>= 7;
60 More = !((((Value == 0 ) && ((Byte & 0x40) == 0)) ||
61 ((Value == -1) && ((Byte & 0x40) != 0))));
62 Count++;
63 if (More || Count < PadTo)
64 Byte |= 0x80; // Mark this byte to show that more bytes will follow.
65 *p++ = Byte;
66 } while (More);
67
68 // Pad with 0x80 and emit a terminating byte at the end.
69 if (Count < PadTo) {
70 uint8_t PadValue = Value < 0 ? 0x7f : 0x00;
71 for (; Count < PadTo - 1; ++Count)
72 *p++ = (PadValue | 0x80);
73 *p++ = PadValue;
74 }
75 return (unsigned)(p - orig_p);
76}
77
78/// Utility function to encode a ULEB128 value to an output stream. Returns
79/// the length in bytes of the encoded value.
80inline unsigned encodeULEB128(uint64_t Value, raw_ostream &OS,
81 unsigned PadTo = 0) {
82 unsigned Count = 0;
83 do {
84 uint8_t Byte = Value & 0x7f;
85 Value >>= 7;
86 Count++;
87 if (Value != 0 || Count < PadTo)
88 Byte |= 0x80; // Mark this byte to show that more bytes will follow.
89 OS << char(Byte);
90 } while (Value != 0);
91
92 // Pad with 0x80 and emit a null byte at the end.
93 if (Count < PadTo) {
94 for (; Count < PadTo - 1; ++Count)
95 OS << '\x80';
96 OS << '\x00';
97 Count++;
98 }
99 return Count;
100}
101
102/// Utility function to encode a ULEB128 value to a buffer. Returns
103/// the length in bytes of the encoded value.
104inline unsigned encodeULEB128(uint64_t Value, uint8_t *p,
105 unsigned PadTo = 0) {
106 uint8_t *orig_p = p;
107 unsigned Count = 0;
108 do {
109 uint8_t Byte = Value & 0x7f;
110 Value >>= 7;
111 Count++;
112 if (Value != 0 || Count < PadTo)
113 Byte |= 0x80; // Mark this byte to show that more bytes will follow.
114 *p++ = Byte;
115 } while (Value != 0);
116
117 // Pad with 0x80 and emit a null byte at the end.
118 if (Count < PadTo) {
119 for (; Count < PadTo - 1; ++Count)
120 *p++ = '\x80';
121 *p++ = '\x00';
122 }
123
124 return (unsigned)(p - orig_p);
125}
126
127/// Utility function to decode a ULEB128 value.
128inline uint64_t decodeULEB128(const uint8_t *p, unsigned *n = nullptr,
129 const uint8_t *end = nullptr,
130 const char **error = nullptr) {
131 const uint8_t *orig_p = p;
132 uint64_t Value = 0;
133 unsigned Shift = 0;
134 if (error
3.1
'error' is null
3.1
'error' is null
)
4
←
Taking false branch
→
135 *error = nullptr;
136 do {
137 if (p == end) {
5
←
Assuming 'p' is equal to 'end'
→
6
←
Taking true branch
→
138 if (error
6.1
'error' is null
6.1
'error' is null
)
7
←
Taking false branch
→
139 *error = "malformed uleb128, extends past end";
140 if (n
7.1
'n' is non-null
7.1
'n' is non-null
)
8
←
Taking true branch
→
141 *n = (unsigned)(p - orig_p);
142 return 0;
9
←
Returning zero
→
143 }
144 uint64_t Slice = *p & 0x7f;
145 if ((Shift >= 64 && Slice != 0) || Slice << Shift >> Shift != Slice) {
146 if (error)
147 *error = "uleb128 too big for uint64";
148 if (n)
149 *n = (unsigned)(p - orig_p);
150 return 0;
151 }
152 Value += Slice << Shift;
153 Shift += 7;
154 } while (*p++ >= 128);
155 if (n)
156 *n = (unsigned)(p - orig_p);
157 return Value;
158}
159
160/// Utility function to decode a SLEB128 value.
161inline int64_t decodeSLEB128(const uint8_t *p, unsigned *n = nullptr,
162 const uint8_t *end = nullptr,
163 const char **error = nullptr) {
164 const uint8_t *orig_p = p;
165 int64_t Value = 0;
166 unsigned Shift = 0;
167 uint8_t Byte;
168 if (error)
169 *error = nullptr;
170 do {
171 if (p == end) {
172 if (error)
173 *error = "malformed sleb128, extends past end";
174 if (n)
175 *n = (unsigned)(p - orig_p);
176 return 0;
177 }
178 Byte = *p;
179 uint64_t Slice = Byte & 0x7f;
180 if ((Shift >= 64 && Slice != (Value < 0 ? 0x7f : 0x00)) ||
181 (Shift == 63 && Slice != 0 && Slice != 0x7f)) {
182 if (error)
183 *error = "sleb128 too big for int64";
184 if (n)
185 *n = (unsigned)(p - orig_p);
186 return 0;
187 }
188 Value |= Slice << Shift;
189 Shift += 7;
190 ++p;
191 } while (Byte >= 128);
192 // Sign extend negative numbers if needed.
193 if (Shift < 64 && (Byte & 0x40))
194 Value |= (-1ULL) << Shift;
195 if (n)
196 *n = (unsigned)(p - orig_p);
197 return Value;
198}
199
200/// Utility function to get the size of the ULEB128-encoded value.
201extern unsigned getULEB128Size(uint64_t Value);
202
203/// Utility function to get the size of the SLEB128-encoded value.
204extern unsigned getSLEB128Size(int64_t Value);
205
206} // namespace llvm
207
208#endif // LLVM_SUPPORT_LEB128_H