lib/ProfileData/InstrProf.cpp

   1 //===- InstrProf.cpp - Instrumented profiling format support --------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file contains support for clang's instrumentation based PGO and
  11 // coverage.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/ProfileData/InstrProf.h"
  16 #include "llvm/ADT/ArrayRef.h"
  17 #include "llvm/ADT/SmallString.h"
  18 #include "llvm/ADT/SmallVector.h"
  19 #include "llvm/ADT/StringExtras.h"
  20 #include "llvm/ADT/StringRef.h"
  21 #include "llvm/ADT/Triple.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/Support/Casting.h"
  34 #include "llvm/Support/CommandLine.h"
  35 #include "llvm/Support/Compiler.h"
  36 #include "llvm/Support/Compression.h"
  37 #include "llvm/Support/Endian.h"
  38 #include "llvm/Support/Error.h"
  39 #include "llvm/Support/ErrorHandling.h"
  40 #include "llvm/Support/LEB128.h"
  41 #include "llvm/Support/ManagedStatic.h"
  42 #include "llvm/Support/MathExtras.h"
  43 #include "llvm/Support/Path.h"
  44 #include "llvm/Support/SwapByteOrder.h"
  45 #include <algorithm>
  46 #include <cassert>
  47 #include <cstddef>
  48 #include <cstdint>
  49 #include <cstring>
  50 #include <memory>
  51 #include <string>
  52 #include <system_error>
  53 #include <utility>
  54 #include <vector>
  55
  56 using namespace llvm;
  57
  58 static cl::opt<bool> StaticFuncFullModulePrefix(
  59     "static-func-full-module-prefix", cl::init(true), cl::Hidden,
  60     cl::desc("Use full module build paths in the profile counter names for "
  61              "static functions."));
  62
  63 // This option is tailored to users that have different top-level directory in
  64 // profile-gen and profile-use compilation. Users need to specific the number
  65 // of levels to strip. A value larger than the number of directories in the
  66 // source file will strip all the directory names and only leave the basename.
  67 //
  68 // Note current ThinLTO module importing for the indirect-calls assumes
  69 // the source directory name not being stripped. A non-zero option value here
  70 // can potentially prevent some inter-module indirect-call-promotions.
  71 static cl::opt<unsigned> StaticFuncStripDirNamePrefix(
  72     "static-func-strip-dirname-prefix", cl::init(0), cl::Hidden,
  73     cl::desc("Strip specified level of directory name from source path in "
  74              "the profile counter name for static functions."));
  75
  76 static std::string getInstrProfErrString(instrprof_error Err) {
  77   switch (Err) {
  78   case instrprof_error::success:
  79     return "Success";
  80   case instrprof_error::eof:
  81     return "End of File";
  82   case instrprof_error::unrecognized_format:
  83     return "Unrecognized instrumentation profile encoding format";
  84   case instrprof_error::bad_magic:
  85     return "Invalid instrumentation profile data (bad magic)";
  86   case instrprof_error::bad_header:
  87     return "Invalid instrumentation profile data (file header is corrupt)";
  88   case instrprof_error::unsupported_version:
  89     return "Unsupported instrumentation profile format version";
  90   case instrprof_error::unsupported_hash_type:
  91     return "Unsupported instrumentation profile hash type";
  92   case instrprof_error::too_large:
  93     return "Too much profile data";
  94   case instrprof_error::truncated:
  95     return "Truncated profile data";
  96   case instrprof_error::malformed:
  97     return "Malformed instrumentation profile data";
  98   case instrprof_error::unknown_function:
  99     return "No profile data available for function";
 100   case instrprof_error::hash_mismatch:
 101     return "Function control flow change detected (hash mismatch)";
 102   case instrprof_error::count_mismatch:
 103     return "Function basic block count change detected (counter mismatch)";
 104   case instrprof_error::counter_overflow:
 105     return "Counter overflow";
 106   case instrprof_error::value_site_count_mismatch:
 107     return "Function value site count change detected (counter mismatch)";
 108   case instrprof_error::compress_failed:
 109     return "Failed to compress data (zlib)";
 110   case instrprof_error::uncompress_failed:
 111     return "Failed to uncompress data (zlib)";
 112   case instrprof_error::empty_raw_profile:
 113     return "Empty raw profile file";
 114   case instrprof_error::zlib_unavailable:
 115     return "Profile uses zlib compression but the profile reader was built without zlib support";
 116   }
 117   llvm_unreachable("A value of instrprof_error has no message.");
 118 }
 119
 120 namespace {
 121
 122 // FIXME: This class is only here to support the transition to llvm::Error. It
 123 // will be removed once this transition is complete. Clients should prefer to
 124 // deal with the Error value directly, rather than converting to error_code.
 125 class InstrProfErrorCategoryType : public std::error_category {
 126   const char *name() const noexcept override { return "llvm.instrprof"; }
 127
 128   std::string message(int IE) const override {
 129     return getInstrProfErrString(static_cast<instrprof_error>(IE));
 130   }
 131 };
 132
 133 } // end anonymous namespace
 134
 135 static ManagedStatic<InstrProfErrorCategoryType> ErrorCategory;
 136
 137 const std::error_category &llvm::instrprof_category() {
 138   return *ErrorCategory;
 139 }
 140
 141 namespace {
 142
 143 const char *InstrProfSectNameCommon[] = {
 144 #define INSTR_PROF_SECT_ENTRY(Kind, SectNameCommon, SectNameCoff, Prefix)      \
 145   SectNameCommon,
 146 #include "llvm/ProfileData/InstrProfData.inc"
 147 };
 148
 149 const char *InstrProfSectNameCoff[] = {
 150 #define INSTR_PROF_SECT_ENTRY(Kind, SectNameCommon, SectNameCoff, Prefix)      \
 151   SectNameCoff,
 152 #include "llvm/ProfileData/InstrProfData.inc"
 153 };
 154
 155 const char *InstrProfSectNamePrefix[] = {
 156 #define INSTR_PROF_SECT_ENTRY(Kind, SectNameCommon, SectNameCoff, Prefix)      \
 157   Prefix,
 158 #include "llvm/ProfileData/InstrProfData.inc"
 159 };
 160
 161 } // namespace
 162
 163 namespace llvm {
 164
 165 std::string getInstrProfSectionName(InstrProfSectKind IPSK,
 166                                     Triple::ObjectFormatType OF,
 167                                     bool AddSegmentInfo) {
 168   std::string SectName;
 169
 170   if (OF == Triple::MachO && AddSegmentInfo)
 171     SectName = InstrProfSectNamePrefix[IPSK];
 172
 173   if (OF == Triple::COFF)
 174     SectName += InstrProfSectNameCoff[IPSK];
 175   else
 176     SectName += InstrProfSectNameCommon[IPSK];
 177
 178   if (OF == Triple::MachO && IPSK == IPSK_data && AddSegmentInfo)
 179     SectName += ",regular,live_support";
 180
 181   return SectName;
 182 }
 183
 184 void SoftInstrProfErrors::addError(instrprof_error IE) {
 185   if (IE == instrprof_error::success)
 186     return;
 187
 188   if (FirstError == instrprof_error::success)
 189     FirstError = IE;
 190
 191   switch (IE) {
 192   case instrprof_error::hash_mismatch:
 193     ++NumHashMismatches;
 194     break;
 195   case instrprof_error::count_mismatch:
 196     ++NumCountMismatches;
 197     break;
 198   case instrprof_error::counter_overflow:
 199     ++NumCounterOverflows;
 200     break;
 201   case instrprof_error::value_site_count_mismatch:
 202     ++NumValueSiteCountMismatches;
 203     break;
 204   default:
 205     llvm_unreachable("Not a soft error");
 206   }
 207 }
 208
 209 std::string InstrProfError::message() const {
 210   return getInstrProfErrString(Err);
 211 }
 212
 213 char InstrProfError::ID = 0;
 214
 215 std::string getPGOFuncName(StringRef RawFuncName,
 216                            GlobalValue::LinkageTypes Linkage,
 217                            StringRef FileName,
 218                            uint64_t Version LLVM_ATTRIBUTE_UNUSED) {
 219   return GlobalValue::getGlobalIdentifier(RawFuncName, Linkage, FileName);
 220 }
 221
 222 // Strip NumPrefix level of directory name from PathNameStr. If the number of
 223 // directory separators is less than NumPrefix, strip all the directories and
 224 // leave base file name only.
 225 static StringRef stripDirPrefix(StringRef PathNameStr, uint32_t NumPrefix) {
 226   uint32_t Count = NumPrefix;
 227   uint32_t Pos = 0, LastPos = 0;
 228   for (auto & CI : PathNameStr) {
 229     ++Pos;
 230     if (llvm::sys::path::is_separator(CI)) {
 231       LastPos = Pos;
 232       --Count;
 233     }
 234     if (Count == 0)
 235       break;
 236   }
 237   return PathNameStr.substr(LastPos);
 238 }
 239
 240 // Return the PGOFuncName. This function has some special handling when called
 241 // in LTO optimization. The following only applies when calling in LTO passes
 242 // (when \c InLTO is true): LTO's internalization privatizes many global linkage
 243 // symbols. This happens after value profile annotation, but those internal
 244 // linkage functions should not have a source prefix.
 245 // Additionally, for ThinLTO mode, exported internal functions are promoted
 246 // and renamed. We need to ensure that the original internal PGO name is
 247 // used when computing the GUID that is compared against the profiled GUIDs.
 248 // To differentiate compiler generated internal symbols from original ones,
 249 // PGOFuncName meta data are created and attached to the original internal
 250 // symbols in the value profile annotation step
 251 // (PGOUseFunc::annotateIndirectCallSites). If a symbol does not have the meta
 252 // data, its original linkage must be non-internal.
 253 std::string getPGOFuncName(const Function &F, bool InLTO, uint64_t Version) {
 254   if (!InLTO) {
 255     StringRef FileName = (StaticFuncFullModulePrefix
 256                               ? F.getParent()->getName()
 257                               : sys::path::filename(F.getParent()->getName()));
 258     if (StaticFuncFullModulePrefix && StaticFuncStripDirNamePrefix != 0)
 259       FileName = stripDirPrefix(FileName, StaticFuncStripDirNamePrefix);
 260     return getPGOFuncName(F.getName(), F.getLinkage(), FileName, Version);
 261   }
 262
 263   // In LTO mode (when InLTO is true), first check if there is a meta data.
 264   if (MDNode *MD = getPGOFuncNameMetadata(F)) {
 265     StringRef S = cast<MDString>(MD->getOperand(0))->getString();
 266     return S.str();
 267   }
 268
 269   // If there is no meta data, the function must be a global before the value
 270   // profile annotation pass. Its current linkage may be internal if it is
 271   // internalized in LTO mode.
 272   return getPGOFuncName(F.getName(), GlobalValue::ExternalLinkage, "");
 273 }
 274
 275 StringRef getFuncNameWithoutPrefix(StringRef PGOFuncName, StringRef FileName) {
 276   if (FileName.empty())
 277     return PGOFuncName;
 278   // Drop the file name including ':'. See also getPGOFuncName.
 279   if (PGOFuncName.startswith(FileName))
 280     PGOFuncName = PGOFuncName.drop_front(FileName.size() + 1);
 281   return PGOFuncName;
 282 }
 283
 284 // \p FuncName is the string used as profile lookup key for the function. A
 285 // symbol is created to hold the name. Return the legalized symbol name.
 286 std::string getPGOFuncNameVarName(StringRef FuncName,
 287                                   GlobalValue::LinkageTypes Linkage) {
 288   std::string VarName = getInstrProfNameVarPrefix();
 289   VarName += FuncName;
 290
 291   if (!GlobalValue::isLocalLinkage(Linkage))
 292     return VarName;
 293
 294   // Now fix up illegal chars in local VarName that may upset the assembler.
 295   const char *InvalidChars = "-:<>/\"'";
 296   size_t found = VarName.find_first_of(InvalidChars);
 297   while (found != std::string::npos) {
 298     VarName[found] = '_';
 299     found = VarName.find_first_of(InvalidChars, found + 1);
 300   }
 301   return VarName;
 302 }
 303
 304 GlobalVariable *createPGOFuncNameVar(Module &M,
 305                                      GlobalValue::LinkageTypes Linkage,
 306                                      StringRef PGOFuncName) {
 307   // We generally want to match the function's linkage, but available_externally
 308   // and extern_weak both have the wrong semantics, and anything that doesn't
 309   // need to link across compilation units doesn't need to be visible at all.
 310   if (Linkage == GlobalValue::ExternalWeakLinkage)
 311     Linkage = GlobalValue::LinkOnceAnyLinkage;
 312   else if (Linkage == GlobalValue::AvailableExternallyLinkage)
 313     Linkage = GlobalValue::LinkOnceODRLinkage;
 314   else if (Linkage == GlobalValue::InternalLinkage ||
 315            Linkage == GlobalValue::ExternalLinkage)
 316     Linkage = GlobalValue::PrivateLinkage;
 317
 318   auto *Value =
 319       ConstantDataArray::getString(M.getContext(), PGOFuncName, false);
 320   auto FuncNameVar =
 321       new GlobalVariable(M, Value->getType(), true, Linkage, Value,
 322                          getPGOFuncNameVarName(PGOFuncName, Linkage));
 323
 324   // Hide the symbol so that we correctly get a copy for each executable.
 325   if (!GlobalValue::isLocalLinkage(FuncNameVar->getLinkage()))
 326     FuncNameVar->setVisibility(GlobalValue::HiddenVisibility);
 327
 328   return FuncNameVar;
 329 }
 330
 331 GlobalVariable *createPGOFuncNameVar(Function &F, StringRef PGOFuncName) {
 332   return createPGOFuncNameVar(*F.getParent(), F.getLinkage(), PGOFuncName);
 333 }
 334
 335 Error InstrProfSymtab::create(Module &M, bool InLTO) {
 336   for (Function &F : M) {
 337     // Function may not have a name: like using asm("") to overwrite the name.
 338     // Ignore in this case.
 339     if (!F.hasName())
 340       continue;
 341     const std::string &PGOFuncName = getPGOFuncName(F, InLTO);
 342     if (Error E = addFuncName(PGOFuncName))
 343       return E;
 344     MD5FuncMap.emplace_back(Function::getGUID(PGOFuncName), &F);
 345     // In ThinLTO, local function may have been promoted to global and have
 346     // suffix added to the function name. We need to add the stripped function
 347     // name to the symbol table so that we can find a match from profile.
 348     if (InLTO) {
 349       auto pos = PGOFuncName.find('.');
 350       if (pos != std::string::npos) {
 351         const std::string &OtherFuncName = PGOFuncName.substr(0, pos);
 352         if (Error E = addFuncName(OtherFuncName))
 353           return E;
 354         MD5FuncMap.emplace_back(Function::getGUID(OtherFuncName), &F);
 355       }
 356     }
 357   }
 358   Sorted = false;
 359   finalizeSymtab();
 360   return Error::success();
 361 }
 362
 363 uint64_t InstrProfSymtab::getFunctionHashFromAddress(uint64_t Address) {
 364   finalizeSymtab();
 365   auto Result =
 366       std::lower_bound(AddrToMD5Map.begin(), AddrToMD5Map.end(), Address,
 367                        [](const std::pair<uint64_t, uint64_t> &LHS,
 368                           uint64_t RHS) { return LHS.first < RHS; });
 369   // Raw function pointer collected by value profiler may be from
 370   // external functions that are not instrumented. They won't have
 371   // mapping data to be used by the deserializer. Force the value to
 372   // be 0 in this case.
 373   if (Result != AddrToMD5Map.end() && Result->first == Address)
 374     return (uint64_t)Result->second;
 375   return 0;
 376 }
 377
 378 Error collectPGOFuncNameStrings(ArrayRef<std::string> NameStrs,
 379                                 bool doCompression, std::string &Result) {
 380   assert(!NameStrs.empty() && "No name data to emit");
 381
 382   uint8_t Header[16], *P = Header;
 383   std::string UncompressedNameStrings =
 384       join(NameStrs.begin(), NameStrs.end(), getInstrProfNameSeparator());
 385
 386   assert(StringRef(UncompressedNameStrings)
 387                  .count(getInstrProfNameSeparator()) == (NameStrs.size() - 1) &&
 388          "PGO name is invalid (contains separator token)");
 389
 390   unsigned EncLen = encodeULEB128(UncompressedNameStrings.length(), P);
 391   P += EncLen;
 392
 393   auto WriteStringToResult = [&](size_t CompressedLen, StringRef InputStr) {
 394     EncLen = encodeULEB128(CompressedLen, P);
 395     P += EncLen;
 396     char *HeaderStr = reinterpret_cast<char *>(&Header[0]);
 397     unsigned HeaderLen = P - &Header[0];
 398     Result.append(HeaderStr, HeaderLen);
 399     Result += InputStr;
 400     return Error::success();
 401   };
 402
 403   if (!doCompression) {
 404     return WriteStringToResult(0, UncompressedNameStrings);
 405   }
 406
 407   SmallString<128> CompressedNameStrings;
 408   Error E = zlib::compress(StringRef(UncompressedNameStrings),
 409                            CompressedNameStrings, zlib::BestSizeCompression);
 410   if (E) {
 411     consumeError(std::move(E));
 412     return make_error<InstrProfError>(instrprof_error::compress_failed);
 413   }
 414
 415   return WriteStringToResult(CompressedNameStrings.size(),
 416                              CompressedNameStrings);
 417 }
 418
 419 StringRef getPGOFuncNameVarInitializer(GlobalVariable *NameVar) {
 420   auto *Arr = cast<ConstantDataArray>(NameVar->getInitializer());
 421   StringRef NameStr =
 422       Arr->isCString() ? Arr->getAsCString() : Arr->getAsString();
 423   return NameStr;
 424 }
 425
 426 Error collectPGOFuncNameStrings(ArrayRef<GlobalVariable *> NameVars,
 427                                 std::string &Result, bool doCompression) {
 428   std::vector<std::string> NameStrs;
 429   for (auto *NameVar : NameVars) {
 430     NameStrs.push_back(getPGOFuncNameVarInitializer(NameVar));
 431   }
 432   return collectPGOFuncNameStrings(
 433       NameStrs, zlib::isAvailable() && doCompression, Result);
 434 }
 435
 436 Error readPGOFuncNameStrings(StringRef NameStrings, InstrProfSymtab &Symtab) {
 437   const uint8_t *P = reinterpret_cast<const uint8_t *>(NameStrings.data());
 438   const uint8_t *EndP = reinterpret_cast<const uint8_t *>(NameStrings.data() +
 439                                                           NameStrings.size());
 440   while (P < EndP) {
 441     uint32_t N;
 442     uint64_t UncompressedSize = decodeULEB128(P, &N);
 443     P += N;
 444     uint64_t CompressedSize = decodeULEB128(P, &N);
 445     P += N;
 446     bool isCompressed = (CompressedSize != 0);
 447     SmallString<128> UncompressedNameStrings;
 448     StringRef NameStrings;
 449     if (isCompressed) {
 450       if (!llvm::zlib::isAvailable())
 451         return make_error<InstrProfError>(instrprof_error::zlib_unavailable);
 452
 453       StringRef CompressedNameStrings(reinterpret_cast<const char *>(P),
 454                                       CompressedSize);
 455       if (Error E =
 456               zlib::uncompress(CompressedNameStrings, UncompressedNameStrings,
 457                                UncompressedSize)) {
 458         consumeError(std::move(E));
 459         return make_error<InstrProfError>(instrprof_error::uncompress_failed);
 460       }
 461       P += CompressedSize;
 462       NameStrings = StringRef(UncompressedNameStrings.data(),
 463                               UncompressedNameStrings.size());
 464     } else {
 465       NameStrings =
 466           StringRef(reinterpret_cast<const char *>(P), UncompressedSize);
 467       P += UncompressedSize;
 468     }
 469     // Now parse the name strings.
 470     SmallVector<StringRef, 0> Names;
 471     NameStrings.split(Names, getInstrProfNameSeparator());
 472     for (StringRef &Name : Names)
 473       if (Error E = Symtab.addFuncName(Name))
 474         return E;
 475
 476     while (P < EndP && *P == 0)
 477       P++;
 478   }
 479   return Error::success();
 480 }
 481
 482 void InstrProfValueSiteRecord::merge(InstrProfValueSiteRecord &Input,
 483                                      uint64_t Weight,
 484                                      function_ref<void(instrprof_error)> Warn) {
 485   this->sortByTargetValues();
 486   Input.sortByTargetValues();
 487   auto I = ValueData.begin();
 488   auto IE = ValueData.end();
 489   for (auto J = Input.ValueData.begin(), JE = Input.ValueData.end(); J != JE;
 490        ++J) {
 491     while (I != IE && I->Value < J->Value)
 492       ++I;
 493     if (I != IE && I->Value == J->Value) {
 494       bool Overflowed;
 495       I->Count = SaturatingMultiplyAdd(J->Count, Weight, I->Count, &Overflowed);
 496       if (Overflowed)
 497         Warn(instrprof_error::counter_overflow);
 498       ++I;
 499       continue;
 500     }
 501     ValueData.insert(I, *J);
 502   }
 503 }
 504
 505 void InstrProfValueSiteRecord::scale(uint64_t Weight,
 506                                      function_ref<void(instrprof_error)> Warn) {
 507   for (auto I = ValueData.begin(), IE = ValueData.end(); I != IE; ++I) {
 508     bool Overflowed;
 509     I->Count = SaturatingMultiply(I->Count, Weight, &Overflowed);
 510     if (Overflowed)
 511       Warn(instrprof_error::counter_overflow);
 512   }
 513 }
 514
 515 // Merge Value Profile data from Src record to this record for ValueKind.
 516 // Scale merged value counts by \p Weight.
 517 void InstrProfRecord::mergeValueProfData(
 518     uint32_t ValueKind, InstrProfRecord &Src, uint64_t Weight,
 519     function_ref<void(instrprof_error)> Warn) {
 520   uint32_t ThisNumValueSites = getNumValueSites(ValueKind);
 521   uint32_t OtherNumValueSites = Src.getNumValueSites(ValueKind);
 522   if (ThisNumValueSites != OtherNumValueSites) {
 523     Warn(instrprof_error::value_site_count_mismatch);
 524     return;
 525   }
 526   if (!ThisNumValueSites)
 527     return;
 528   std::vector<InstrProfValueSiteRecord> &ThisSiteRecords =
 529       getOrCreateValueSitesForKind(ValueKind);
 530   MutableArrayRef<InstrProfValueSiteRecord> OtherSiteRecords =
 531       Src.getValueSitesForKind(ValueKind);
 532   for (uint32_t I = 0; I < ThisNumValueSites; I++)
 533     ThisSiteRecords[I].merge(OtherSiteRecords[I], Weight, Warn);
 534 }
 535
 536 void InstrProfRecord::merge(InstrProfRecord &Other, uint64_t Weight,
 537                             function_ref<void(instrprof_error)> Warn) {
 538   // If the number of counters doesn't match we either have bad data
 539   // or a hash collision.
 540   if (Counts.size() != Other.Counts.size()) {
 541     Warn(instrprof_error::count_mismatch);
 542     return;
 543   }
 544
 545   for (size_t I = 0, E = Other.Counts.size(); I < E; ++I) {
 546     bool Overflowed;
 547     Counts[I] =
 548         SaturatingMultiplyAdd(Other.Counts[I], Weight, Counts[I], &Overflowed);
 549     if (Overflowed)
 550       Warn(instrprof_error::counter_overflow);
 551   }
 552
 553   for (uint32_t Kind = IPVK_First; Kind <= IPVK_Last; ++Kind)
 554     mergeValueProfData(Kind, Other, Weight, Warn);
 555 }
 556
 557 void InstrProfRecord::scaleValueProfData(
 558     uint32_t ValueKind, uint64_t Weight,
 559     function_ref<void(instrprof_error)> Warn) {
 560   for (auto &R : getValueSitesForKind(ValueKind))
 561     R.scale(Weight, Warn);
 562 }
 563
 564 void InstrProfRecord::scale(uint64_t Weight,
 565                             function_ref<void(instrprof_error)> Warn) {
 566   for (auto &Count : this->Counts) {
 567     bool Overflowed;
 568     Count = SaturatingMultiply(Count, Weight, &Overflowed);
 569     if (Overflowed)
 570       Warn(instrprof_error::counter_overflow);
 571   }
 572   for (uint32_t Kind = IPVK_First; Kind <= IPVK_Last; ++Kind)
 573     scaleValueProfData(Kind, Weight, Warn);
 574 }
 575
 576 // Map indirect call target name hash to name string.
 577 uint64_t InstrProfRecord::remapValue(uint64_t Value, uint32_t ValueKind,
 578                                      InstrProfSymtab *SymTab) {
 579   if (!SymTab)
 580     return Value;
 581
 582   if (ValueKind == IPVK_IndirectCallTarget)
 583     return SymTab->getFunctionHashFromAddress(Value);
 584
 585   return Value;
 586 }
 587
 588 void InstrProfRecord::addValueData(uint32_t ValueKind, uint32_t Site,
 589                                    InstrProfValueData *VData, uint32_t N,
 590                                    InstrProfSymtab *ValueMap) {
 591   for (uint32_t I = 0; I < N; I++) {
 592     VData[I].Value = remapValue(VData[I].Value, ValueKind, ValueMap);
 593   }
 594   std::vector<InstrProfValueSiteRecord> &ValueSites =
 595       getOrCreateValueSitesForKind(ValueKind);
 596   if (N == 0)
 597     ValueSites.emplace_back();
 598   else
 599     ValueSites.emplace_back(VData, VData + N);
 600 }
 601
 602 #define INSTR_PROF_COMMON_API_IMPL
 603 #include "llvm/ProfileData/InstrProfData.inc"
 604
 605 /*!
 606  * ValueProfRecordClosure Interface implementation for  InstrProfRecord
 607  *  class. These C wrappers are used as adaptors so that C++ code can be
 608  *  invoked as callbacks.
 609  */
 610 uint32_t getNumValueKindsInstrProf(const void *Record) {
 611   return reinterpret_cast<const InstrProfRecord *>(Record)->getNumValueKinds();
 612 }
 613
 614 uint32_t getNumValueSitesInstrProf(const void *Record, uint32_t VKind) {
 615   return reinterpret_cast<const InstrProfRecord *>(Record)
 616       ->getNumValueSites(VKind);
 617 }
 618
 619 uint32_t getNumValueDataInstrProf(const void *Record, uint32_t VKind) {
 620   return reinterpret_cast<const InstrProfRecord *>(Record)
 621       ->getNumValueData(VKind);
 622 }
 623
 624 uint32_t getNumValueDataForSiteInstrProf(const void *R, uint32_t VK,
 625                                          uint32_t S) {
 626   return reinterpret_cast<const InstrProfRecord *>(R)
 627       ->getNumValueDataForSite(VK, S);
 628 }
 629
 630 void getValueForSiteInstrProf(const void *R, InstrProfValueData *Dst,
 631                               uint32_t K, uint32_t S) {
 632   reinterpret_cast<const InstrProfRecord *>(R)->getValueForSite(Dst, K, S);
 633 }
 634
 635 ValueProfData *allocValueProfDataInstrProf(size_t TotalSizeInBytes) {
 636   ValueProfData *VD =
 637       (ValueProfData *)(new (::operator new(TotalSizeInBytes)) ValueProfData());
 638   memset(VD, 0, TotalSizeInBytes);
 639   return VD;
 640 }
 641
 642 static ValueProfRecordClosure InstrProfRecordClosure = {
 643     nullptr,
 644     getNumValueKindsInstrProf,
 645     getNumValueSitesInstrProf,
 646     getNumValueDataInstrProf,
 647     getNumValueDataForSiteInstrProf,
 648     nullptr,
 649     getValueForSiteInstrProf,
 650     allocValueProfDataInstrProf};
 651
 652 // Wrapper implementation using the closure mechanism.
 653 uint32_t ValueProfData::getSize(const InstrProfRecord &Record) {
 654   auto Closure = InstrProfRecordClosure;
 655   Closure.Record = &Record;
 656   return getValueProfDataSize(&Closure);
 657 }
 658
 659 // Wrapper implementation using the closure mechanism.
 660 std::unique_ptr<ValueProfData>
 661 ValueProfData::serializeFrom(const InstrProfRecord &Record) {
 662   InstrProfRecordClosure.Record = &Record;
 663
 664   std::unique_ptr<ValueProfData> VPD(
 665       serializeValueProfDataFrom(&InstrProfRecordClosure, nullptr));
 666   return VPD;
 667 }
 668
 669 void ValueProfRecord::deserializeTo(InstrProfRecord &Record,
 670                                     InstrProfSymtab *SymTab) {
 671   Record.reserveSites(Kind, NumValueSites);
 672
 673   InstrProfValueData *ValueData = getValueProfRecordValueData(this);
 674   for (uint64_t VSite = 0; VSite < NumValueSites; ++VSite) {
 675     uint8_t ValueDataCount = this->SiteCountArray[VSite];
 676     Record.addValueData(Kind, VSite, ValueData, ValueDataCount, SymTab);
 677     ValueData += ValueDataCount;
 678   }
 679 }
 680
 681 // For writing/serializing,  Old is the host endianness, and  New is
 682 // byte order intended on disk. For Reading/deserialization, Old
 683 // is the on-disk source endianness, and New is the host endianness.
 684 void ValueProfRecord::swapBytes(support::endianness Old,
 685                                 support::endianness New) {
 686   using namespace support;
 687
 688   if (Old == New)
 689     return;
 690
 691   if (getHostEndianness() != Old) {
 692     sys::swapByteOrder<uint32_t>(NumValueSites);
 693     sys::swapByteOrder<uint32_t>(Kind);
 694   }
 695   uint32_t ND = getValueProfRecordNumValueData(this);
 696   InstrProfValueData *VD = getValueProfRecordValueData(this);
 697
 698   // No need to swap byte array: SiteCountArrray.
 699   for (uint32_t I = 0; I < ND; I++) {
 700     sys::swapByteOrder<uint64_t>(VD[I].Value);
 701     sys::swapByteOrder<uint64_t>(VD[I].Count);
 702   }
 703   if (getHostEndianness() == Old) {
 704     sys::swapByteOrder<uint32_t>(NumValueSites);
 705     sys::swapByteOrder<uint32_t>(Kind);
 706   }
 707 }
 708
 709 void ValueProfData::deserializeTo(InstrProfRecord &Record,
 710                                   InstrProfSymtab *SymTab) {
 711   if (NumValueKinds == 0)
 712     return;
 713
 714   ValueProfRecord *VR = getFirstValueProfRecord(this);
 715   for (uint32_t K = 0; K < NumValueKinds; K++) {
 716     VR->deserializeTo(Record, SymTab);
 717     VR = getValueProfRecordNext(VR);
 718   }
 719 }
 720
 721 template <class T>
 722 static T swapToHostOrder(const unsigned char *&D, support::endianness Orig) {
 723   using namespace support;
 724
 725   if (Orig == little)
 726     return endian::readNext<T, little, unaligned>(D);
 727   else
 728     return endian::readNext<T, big, unaligned>(D);
 729 }
 730
 731 static std::unique_ptr<ValueProfData> allocValueProfData(uint32_t TotalSize) {
 732   return std::unique_ptr<ValueProfData>(new (::operator new(TotalSize))
 733                                             ValueProfData());
 734 }
 735
 736 Error ValueProfData::checkIntegrity() {
 737   if (NumValueKinds > IPVK_Last + 1)
 738     return make_error<InstrProfError>(instrprof_error::malformed);
 739   // Total size needs to be mulltiple of quadword size.
 740   if (TotalSize % sizeof(uint64_t))
 741     return make_error<InstrProfError>(instrprof_error::malformed);
 742
 743   ValueProfRecord *VR = getFirstValueProfRecord(this);
 744   for (uint32_t K = 0; K < this->NumValueKinds; K++) {
 745     if (VR->Kind > IPVK_Last)
 746       return make_error<InstrProfError>(instrprof_error::malformed);
 747     VR = getValueProfRecordNext(VR);
 748     if ((char *)VR - (char *)this > (ptrdiff_t)TotalSize)
 749       return make_error<InstrProfError>(instrprof_error::malformed);
 750   }
 751   return Error::success();
 752 }
 753
 754 Expected<std::unique_ptr<ValueProfData>>
 755 ValueProfData::getValueProfData(const unsigned char *D,
 756                                 const unsigned char *const BufferEnd,
 757                                 support::endianness Endianness) {
 758   using namespace support;
 759
 760   if (D + sizeof(ValueProfData) > BufferEnd)
 761     return make_error<InstrProfError>(instrprof_error::truncated);
 762
 763   const unsigned char *Header = D;
 764   uint32_t TotalSize = swapToHostOrder<uint32_t>(Header, Endianness);
 765   if (D + TotalSize > BufferEnd)
 766     return make_error<InstrProfError>(instrprof_error::too_large);
 767
 768   std::unique_ptr<ValueProfData> VPD = allocValueProfData(TotalSize);
 769   memcpy(VPD.get(), D, TotalSize);
 770   // Byte swap.
 771   VPD->swapBytesToHost(Endianness);
 772
 773   Error E = VPD->checkIntegrity();
 774   if (E)
 775     return std::move(E);
 776
 777   return std::move(VPD);
 778 }
 779
 780 void ValueProfData::swapBytesToHost(support::endianness Endianness) {
 781   using namespace support;
 782
 783   if (Endianness == getHostEndianness())
 784     return;
 785
 786   sys::swapByteOrder<uint32_t>(TotalSize);
 787   sys::swapByteOrder<uint32_t>(NumValueKinds);
 788
 789   ValueProfRecord *VR = getFirstValueProfRecord(this);
 790   for (uint32_t K = 0; K < NumValueKinds; K++) {
 791     VR->swapBytes(Endianness, getHostEndianness());
 792     VR = getValueProfRecordNext(VR);
 793   }
 794 }
 795
 796 void ValueProfData::swapBytesFromHost(support::endianness Endianness) {
 797   using namespace support;
 798
 799   if (Endianness == getHostEndianness())
 800     return;
 801
 802   ValueProfRecord *VR = getFirstValueProfRecord(this);
 803   for (uint32_t K = 0; K < NumValueKinds; K++) {
 804     ValueProfRecord *NVR = getValueProfRecordNext(VR);
 805     VR->swapBytes(getHostEndianness(), Endianness);
 806     VR = NVR;
 807   }
 808   sys::swapByteOrder<uint32_t>(TotalSize);
 809   sys::swapByteOrder<uint32_t>(NumValueKinds);
 810 }
 811
 812 void annotateValueSite(Module &M, Instruction &Inst,
 813                        const InstrProfRecord &InstrProfR,
 814                        InstrProfValueKind ValueKind, uint32_t SiteIdx,
 815                        uint32_t MaxMDCount) {
 816   uint32_t NV = InstrProfR.getNumValueDataForSite(ValueKind, SiteIdx);
 817   if (!NV)
 818     return;
 819
 820   uint64_t Sum = 0;
 821   std::unique_ptr<InstrProfValueData[]> VD =
 822       InstrProfR.getValueForSite(ValueKind, SiteIdx, &Sum);
 823
 824   ArrayRef<InstrProfValueData> VDs(VD.get(), NV);
 825   annotateValueSite(M, Inst, VDs, Sum, ValueKind, MaxMDCount);
 826 }
 827
 828 void annotateValueSite(Module &M, Instruction &Inst,
 829                        ArrayRef<InstrProfValueData> VDs,
 830                        uint64_t Sum, InstrProfValueKind ValueKind,
 831                        uint32_t MaxMDCount) {
 832   LLVMContext &Ctx = M.getContext();
 833   MDBuilder MDHelper(Ctx);
 834   SmallVector<Metadata *, 3> Vals;
 835   // Tag
 836   Vals.push_back(MDHelper.createString("VP"));
 837   // Value Kind
 838   Vals.push_back(MDHelper.createConstant(
 839       ConstantInt::get(Type::getInt32Ty(Ctx), ValueKind)));
 840   // Total Count
 841   Vals.push_back(
 842       MDHelper.createConstant(ConstantInt::get(Type::getInt64Ty(Ctx), Sum)));
 843
 844   // Value Profile Data
 845   uint32_t MDCount = MaxMDCount;
 846   for (auto &VD : VDs) {
 847     Vals.push_back(MDHelper.createConstant(
 848         ConstantInt::get(Type::getInt64Ty(Ctx), VD.Value)));
 849     Vals.push_back(MDHelper.createConstant(
 850         ConstantInt::get(Type::getInt64Ty(Ctx), VD.Count)));
 851     if (--MDCount == 0)
 852       break;
 853   }
 854   Inst.setMetadata(LLVMContext::MD_prof, MDNode::get(Ctx, Vals));
 855 }
 856
 857 bool getValueProfDataFromInst(const Instruction &Inst,
 858                               InstrProfValueKind ValueKind,
 859                               uint32_t MaxNumValueData,
 860                               InstrProfValueData ValueData[],
 861                               uint32_t &ActualNumValueData, uint64_t &TotalC) {
 862   MDNode *MD = Inst.getMetadata(LLVMContext::MD_prof);
 863   if (!MD)
 864     return false;
 865
 866   unsigned NOps = MD->getNumOperands();
 867
 868   if (NOps < 5)
 869     return false;
 870
 871   // Operand 0 is a string tag "VP":
 872   MDString *Tag = cast<MDString>(MD->getOperand(0));
 873   if (!Tag)
 874     return false;
 875
 876   if (!Tag->getString().equals("VP"))
 877     return false;
 878
 879   // Now check kind:
 880   ConstantInt *KindInt = mdconst::dyn_extract<ConstantInt>(MD->getOperand(1));
 881   if (!KindInt)
 882     return false;
 883   if (KindInt->getZExtValue() != ValueKind)
 884     return false;
 885
 886   // Get total count
 887   ConstantInt *TotalCInt = mdconst::dyn_extract<ConstantInt>(MD->getOperand(2));
 888   if (!TotalCInt)
 889     return false;
 890   TotalC = TotalCInt->getZExtValue();
 891
 892   ActualNumValueData = 0;
 893
 894   for (unsigned I = 3; I < NOps; I += 2) {
 895     if (ActualNumValueData >= MaxNumValueData)
 896       break;
 897     ConstantInt *Value = mdconst::dyn_extract<ConstantInt>(MD->getOperand(I));
 898     ConstantInt *Count =
 899         mdconst::dyn_extract<ConstantInt>(MD->getOperand(I + 1));
 900     if (!Value || !Count)
 901       return false;
 902     ValueData[ActualNumValueData].Value = Value->getZExtValue();
 903     ValueData[ActualNumValueData].Count = Count->getZExtValue();
 904     ActualNumValueData++;
 905   }
 906   return true;
 907 }
 908
 909 MDNode *getPGOFuncNameMetadata(const Function &F) {
 910   return F.getMetadata(getPGOFuncNameMetadataName());
 911 }
 912
 913 void createPGOFuncNameMetadata(Function &F, StringRef PGOFuncName) {
 914   // Only for internal linkage functions.
 915   if (PGOFuncName == F.getName())
 916       return;
 917   // Don't create duplicated meta-data.
 918   if (getPGOFuncNameMetadata(F))
 919     return;
 920   LLVMContext &C = F.getContext();
 921   MDNode *N = MDNode::get(C, MDString::get(C, PGOFuncName));
 922   F.setMetadata(getPGOFuncNameMetadataName(), N);
 923 }
 924
 925 bool needsComdatForCounter(const Function &F, const Module &M) {
 926   if (F.hasComdat())
 927     return true;
 928
 929   if (!Triple(M.getTargetTriple()).supportsCOMDAT())
 930     return false;
 931
 932   // See createPGOFuncNameVar for more details. To avoid link errors, profile
 933   // counters for function with available_externally linkage needs to be changed
 934   // to linkonce linkage. On ELF based systems, this leads to weak symbols to be
 935   // created. Without using comdat, duplicate entries won't be removed by the
 936   // linker leading to increased data segement size and raw profile size. Even
 937   // worse, since the referenced counter from profile per-function data object
 938   // will be resolved to the common strong definition, the profile counts for
 939   // available_externally functions will end up being duplicated in raw profile
 940   // data. This can result in distorted profile as the counts of those dups
 941   // will be accumulated by the profile merger.
 942   GlobalValue::LinkageTypes Linkage = F.getLinkage();
 943   if (Linkage != GlobalValue::ExternalWeakLinkage &&
 944       Linkage != GlobalValue::AvailableExternallyLinkage)
 945     return false;
 946
 947   return true;
 948 }
 949
 950 // Check if INSTR_PROF_RAW_VERSION_VAR is defined.
 951 bool isIRPGOFlagSet(const Module *M) {
 952   auto IRInstrVar =
 953       M->getNamedGlobal(INSTR_PROF_QUOTE(INSTR_PROF_RAW_VERSION_VAR));
 954   if (!IRInstrVar || IRInstrVar->isDeclaration() ||
 955       IRInstrVar->hasLocalLinkage())
 956     return false;
 957
 958   // Check if the flag is set.
 959   if (!IRInstrVar->hasInitializer())
 960     return false;
 961
 962   const Constant *InitVal = IRInstrVar->getInitializer();
 963   if (!InitVal)
 964     return false;
 965
 966   return (dyn_cast<ConstantInt>(InitVal)->getZExtValue() &
 967           VARIANT_MASK_IR_PROF) != 0;
 968 }
 969
 970 // Check if we can safely rename this Comdat function.
 971 bool canRenameComdatFunc(const Function &F, bool CheckAddressTaken) {
 972   if (F.getName().empty())
 973     return false;
 974   if (!needsComdatForCounter(F, *(F.getParent())))
 975     return false;
 976   // Unsafe to rename the address-taken function (which can be used in
 977   // function comparison).
 978   if (CheckAddressTaken && F.hasAddressTaken())
 979     return false;
 980   // Only safe to do if this function may be discarded if it is not used
 981   // in the compilation unit.
 982   if (!GlobalValue::isDiscardableIfUnused(F.getLinkage()))
 983     return false;
 984
 985   // For AvailableExternallyLinkage functions.
 986   if (!F.hasComdat()) {
 987     assert(F.getLinkage() == GlobalValue::AvailableExternallyLinkage);
 988     return true;
 989   }
 990   return true;
 991 }
 992
 993 // Parse the value profile options.
 994 void getMemOPSizeRangeFromOption(StringRef MemOPSizeRange, int64_t &RangeStart,
 995                                  int64_t &RangeLast) {
 996   static const int64_t DefaultMemOPSizeRangeStart = 0;
 997   static const int64_t DefaultMemOPSizeRangeLast = 8;
 998   RangeStart = DefaultMemOPSizeRangeStart;
 999   RangeLast = DefaultMemOPSizeRangeLast;
1000
1001   if (!MemOPSizeRange.empty()) {
1002     auto Pos = MemOPSizeRange.find(':');
1003     if (Pos != std::string::npos) {
1004       if (Pos > 0)
1005         MemOPSizeRange.substr(0, Pos).getAsInteger(10, RangeStart);
1006       if (Pos < MemOPSizeRange.size() - 1)
1007         MemOPSizeRange.substr(Pos + 1).getAsInteger(10, RangeLast);
1008     } else
1009       MemOPSizeRange.getAsInteger(10, RangeLast);
1010   }
1011   assert(RangeLast >= RangeStart);
1012 }
1013
1014 } // end namespace llvm