1 //===- ModuleSummaryAnalysis.cpp - Module summary index builder -----------===// 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 pass builds a ModuleSummaryIndex object for the module, to be written 11 // to bitcode or LLVM assembly. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "llvm/Analysis/ModuleSummaryAnalysis.h" 16 #include "llvm/ADT/ArrayRef.h" 17 #include "llvm/ADT/DenseSet.h" 18 #include "llvm/ADT/MapVector.h" 19 #include "llvm/ADT/STLExtras.h" 20 #include "llvm/ADT/SetVector.h" 21 #include "llvm/ADT/SmallPtrSet.h" 22 #include "llvm/ADT/SmallVector.h" 23 #include "llvm/ADT/StringRef.h" 24 #include "llvm/Analysis/BlockFrequencyInfo.h" 25 #include "llvm/Analysis/BranchProbabilityInfo.h" 26 #include "llvm/Analysis/IndirectCallPromotionAnalysis.h" 27 #include "llvm/Analysis/LoopInfo.h" 28 #include "llvm/Analysis/ProfileSummaryInfo.h" 29 #include "llvm/Analysis/TypeMetadataUtils.h" 30 #include "llvm/IR/Attributes.h" 31 #include "llvm/IR/BasicBlock.h" 32 #include "llvm/IR/CallSite.h" 33 #include "llvm/IR/Constant.h" 34 #include "llvm/IR/Constants.h" 35 #include "llvm/IR/Dominators.h" 36 #include "llvm/IR/Function.h" 37 #include "llvm/IR/GlobalAlias.h" 38 #include "llvm/IR/GlobalValue.h" 39 #include "llvm/IR/GlobalVariable.h" 40 #include "llvm/IR/Instructions.h" 41 #include "llvm/IR/IntrinsicInst.h" 42 #include "llvm/IR/Intrinsics.h" 43 #include "llvm/IR/Metadata.h" 44 #include "llvm/IR/Module.h" 45 #include "llvm/IR/ModuleSummaryIndex.h" 46 #include "llvm/IR/Use.h" 47 #include "llvm/IR/User.h" 48 #include "llvm/Object/ModuleSymbolTable.h" 49 #include "llvm/Object/SymbolicFile.h" 50 #include "llvm/Pass.h" 51 #include "llvm/Support/Casting.h" 52 #include "llvm/Support/CommandLine.h" 53 #include <algorithm> 54 #include <cassert> 55 #include <cstdint> 56 #include <vector> 57 58 using namespace llvm; 59 60 #define DEBUG_TYPE "module-summary-analysis" 61 62 // Option to force edges cold which will block importing when the 63 // -import-cold-multiplier is set to 0. Useful for debugging. 64 FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold = 65 FunctionSummary::FSHT_None; 66 cl::opt<FunctionSummary::ForceSummaryHotnessType, true> FSEC( 67 "force-summary-edges-cold", cl::Hidden, cl::location(ForceSummaryEdgesCold), 68 cl::desc("Force all edges in the function summary to cold"), 69 cl::values(clEnumValN(FunctionSummary::FSHT_None, "none", "None."), 70 clEnumValN(FunctionSummary::FSHT_AllNonCritical, 71 "all-non-critical", "All non-critical edges."), 72 clEnumValN(FunctionSummary::FSHT_All, "all", "All edges."))); 73 74 // Walk through the operands of a given User via worklist iteration and populate 75 // the set of GlobalValue references encountered. Invoked either on an 76 // Instruction or a GlobalVariable (which walks its initializer). 77 // Return true if any of the operands contains blockaddress. This is important 78 // to know when computing summary for global var, because if global variable 79 // references basic block address we can't import it separately from function 80 // containing that basic block. For simplicity we currently don't import such 81 // global vars at all. When importing function we aren't interested if any 82 // instruction in it takes an address of any basic block, because instruction 83 // can only take an address of basic block located in the same function. 84 static bool findRefEdges(ModuleSummaryIndex &Index, const User *CurUser, 85 SetVector<ValueInfo> &RefEdges, 86 SmallPtrSet<const User *, 8> &Visited) { 87 bool HasBlockAddress = false; 88 SmallVector<const User *, 32> Worklist; 89 Worklist.push_back(CurUser); 90 91 while (!Worklist.empty()) { 92 const User *U = Worklist.pop_back_val(); 93 94 if (!Visited.insert(U).second) 95 continue; 96 97 ImmutableCallSite CS(U); 98 99 for (const auto &OI : U->operands()) { 100 const User *Operand = dyn_cast<User>(OI); 101 if (!Operand) 102 continue; 103 if (isa<BlockAddress>(Operand)) { 104 HasBlockAddress = true; 105 continue; 106 } 107 if (auto *GV = dyn_cast<GlobalValue>(Operand)) { 108 // We have a reference to a global value. This should be added to 109 // the reference set unless it is a callee. Callees are handled 110 // specially by WriteFunction and are added to a separate list. 111 if (!(CS && CS.isCallee(&OI))) 112 RefEdges.insert(Index.getOrInsertValueInfo(GV)); 113 continue; 114 } 115 Worklist.push_back(Operand); 116 } 117 } 118 return HasBlockAddress; 119 } 120 121 static CalleeInfo::HotnessType getHotness(uint64_t ProfileCount, 122 ProfileSummaryInfo *PSI) { 123 if (!PSI) 124 return CalleeInfo::HotnessType::Unknown; 125 if (PSI->isHotCount(ProfileCount)) 126 return CalleeInfo::HotnessType::Hot; 127 if (PSI->isColdCount(ProfileCount)) 128 return CalleeInfo::HotnessType::Cold; 129 return CalleeInfo::HotnessType::None; 130 } 131 132 static bool isNonRenamableLocal(const GlobalValue &GV) { 133 return GV.hasSection() && GV.hasLocalLinkage(); 134 } 135 136 /// Determine whether this call has all constant integer arguments (excluding 137 /// "this") and summarize it to VCalls or ConstVCalls as appropriate. 138 static void addVCallToSet(DevirtCallSite Call, GlobalValue::GUID Guid, 139 SetVector<FunctionSummary::VFuncId> &VCalls, 140 SetVector<FunctionSummary::ConstVCall> &ConstVCalls) { 141 std::vector<uint64_t> Args; 142 // Start from the second argument to skip the "this" pointer. 143 for (auto &Arg : make_range(Call.CS.arg_begin() + 1, Call.CS.arg_end())) { 144 auto *CI = dyn_cast<ConstantInt>(Arg); 145 if (!CI || CI->getBitWidth() > 64) { 146 VCalls.insert({Guid, Call.Offset}); 147 return; 148 } 149 Args.push_back(CI->getZExtValue()); 150 } 151 ConstVCalls.insert({{Guid, Call.Offset}, std::move(Args)}); 152 } 153 154 /// If this intrinsic call requires that we add information to the function 155 /// summary, do so via the non-constant reference arguments. 156 static void addIntrinsicToSummary( 157 const CallInst *CI, SetVector<GlobalValue::GUID> &TypeTests, 158 SetVector<FunctionSummary::VFuncId> &TypeTestAssumeVCalls, 159 SetVector<FunctionSummary::VFuncId> &TypeCheckedLoadVCalls, 160 SetVector<FunctionSummary::ConstVCall> &TypeTestAssumeConstVCalls, 161 SetVector<FunctionSummary::ConstVCall> &TypeCheckedLoadConstVCalls, 162 DominatorTree &DT) { 163 switch (CI->getCalledFunction()->getIntrinsicID()) { 164 case Intrinsic::type_test: { 165 auto *TypeMDVal = cast<MetadataAsValue>(CI->getArgOperand(1)); 166 auto *TypeId = dyn_cast<MDString>(TypeMDVal->getMetadata()); 167 if (!TypeId) 168 break; 169 GlobalValue::GUID Guid = GlobalValue::getGUID(TypeId->getString()); 170 171 // Produce a summary from type.test intrinsics. We only summarize type.test 172 // intrinsics that are used other than by an llvm.assume intrinsic. 173 // Intrinsics that are assumed are relevant only to the devirtualization 174 // pass, not the type test lowering pass. 175 bool HasNonAssumeUses = llvm::any_of(CI->uses(), [](const Use &CIU) { 176 auto *AssumeCI = dyn_cast<CallInst>(CIU.getUser()); 177 if (!AssumeCI) 178 return true; 179 Function *F = AssumeCI->getCalledFunction(); 180 return !F || F->getIntrinsicID() != Intrinsic::assume; 181 }); 182 if (HasNonAssumeUses) 183 TypeTests.insert(Guid); 184 185 SmallVector<DevirtCallSite, 4> DevirtCalls; 186 SmallVector<CallInst *, 4> Assumes; 187 findDevirtualizableCallsForTypeTest(DevirtCalls, Assumes, CI, DT); 188 for (auto &Call : DevirtCalls) 189 addVCallToSet(Call, Guid, TypeTestAssumeVCalls, 190 TypeTestAssumeConstVCalls); 191 192 break; 193 } 194 195 case Intrinsic::type_checked_load: { 196 auto *TypeMDVal = cast<MetadataAsValue>(CI->getArgOperand(2)); 197 auto *TypeId = dyn_cast<MDString>(TypeMDVal->getMetadata()); 198 if (!TypeId) 199 break; 200 GlobalValue::GUID Guid = GlobalValue::getGUID(TypeId->getString()); 201 202 SmallVector<DevirtCallSite, 4> DevirtCalls; 203 SmallVector<Instruction *, 4> LoadedPtrs; 204 SmallVector<Instruction *, 4> Preds; 205 bool HasNonCallUses = false; 206 findDevirtualizableCallsForTypeCheckedLoad(DevirtCalls, LoadedPtrs, Preds, 207 HasNonCallUses, CI, DT); 208 // Any non-call uses of the result of llvm.type.checked.load will 209 // prevent us from optimizing away the llvm.type.test. 210 if (HasNonCallUses) 211 TypeTests.insert(Guid); 212 for (auto &Call : DevirtCalls) 213 addVCallToSet(Call, Guid, TypeCheckedLoadVCalls, 214 TypeCheckedLoadConstVCalls); 215 216 break; 217 } 218 default: 219 break; 220 } 221 } 222 223 static void computeFunctionSummary( 224 ModuleSummaryIndex &Index, const Module &M, const Function &F, 225 BlockFrequencyInfo *BFI, ProfileSummaryInfo *PSI, DominatorTree &DT, 226 bool HasLocalsInUsedOrAsm, DenseSet<GlobalValue::GUID> &CantBePromoted) { 227 // Summary not currently supported for anonymous functions, they should 228 // have been named. 229 assert(F.hasName()); 230 231 unsigned NumInsts = 0; 232 // Map from callee ValueId to profile count. Used to accumulate profile 233 // counts for all static calls to a given callee. 234 MapVector<ValueInfo, CalleeInfo> CallGraphEdges; 235 SetVector<ValueInfo> RefEdges; 236 SetVector<GlobalValue::GUID> TypeTests; 237 SetVector<FunctionSummary::VFuncId> TypeTestAssumeVCalls, 238 TypeCheckedLoadVCalls; 239 SetVector<FunctionSummary::ConstVCall> TypeTestAssumeConstVCalls, 240 TypeCheckedLoadConstVCalls; 241 ICallPromotionAnalysis ICallAnalysis; 242 SmallPtrSet<const User *, 8> Visited; 243 244 // Add personality function, prefix data and prologue data to function's ref 245 // list. 246 findRefEdges(Index, &F, RefEdges, Visited); 247 248 bool HasInlineAsmMaybeReferencingInternal = false; 249 for (const BasicBlock &BB : F) 250 for (const Instruction &I : BB) { 251 if (isa<DbgInfoIntrinsic>(I)) 252 continue; 253 ++NumInsts; 254 findRefEdges(Index, &I, RefEdges, Visited); 255 auto CS = ImmutableCallSite(&I); 256 if (!CS) 257 continue; 258 259 const auto *CI = dyn_cast<CallInst>(&I); 260 // Since we don't know exactly which local values are referenced in inline 261 // assembly, conservatively mark the function as possibly referencing 262 // a local value from inline assembly to ensure we don't export a 263 // reference (which would require renaming and promotion of the 264 // referenced value). 265 if (HasLocalsInUsedOrAsm && CI && CI->isInlineAsm()) 266 HasInlineAsmMaybeReferencingInternal = true; 267 268 auto *CalledValue = CS.getCalledValue(); 269 auto *CalledFunction = CS.getCalledFunction(); 270 if (CalledValue && !CalledFunction) { 271 CalledValue = CalledValue->stripPointerCastsNoFollowAliases(); 272 // Stripping pointer casts can reveal a called function. 273 CalledFunction = dyn_cast<Function>(CalledValue); 274 } 275 // Check if this is an alias to a function. If so, get the 276 // called aliasee for the checks below. 277 if (auto *GA = dyn_cast<GlobalAlias>(CalledValue)) { 278 assert(!CalledFunction && "Expected null called function in callsite for alias"); 279 CalledFunction = dyn_cast<Function>(GA->getBaseObject()); 280 } 281 // Check if this is a direct call to a known function or a known 282 // intrinsic, or an indirect call with profile data. 283 if (CalledFunction) { 284 if (CI && CalledFunction->isIntrinsic()) { 285 addIntrinsicToSummary( 286 CI, TypeTests, TypeTestAssumeVCalls, TypeCheckedLoadVCalls, 287 TypeTestAssumeConstVCalls, TypeCheckedLoadConstVCalls, DT); 288 continue; 289 } 290 // We should have named any anonymous globals 291 assert(CalledFunction->hasName()); 292 auto ScaledCount = PSI->getProfileCount(&I, BFI); 293 auto Hotness = ScaledCount ? getHotness(ScaledCount.getValue(), PSI) 294 : CalleeInfo::HotnessType::Unknown; 295 if (ForceSummaryEdgesCold != FunctionSummary::FSHT_None) 296 Hotness = CalleeInfo::HotnessType::Cold; 297 298 // Use the original CalledValue, in case it was an alias. We want 299 // to record the call edge to the alias in that case. Eventually 300 // an alias summary will be created to associate the alias and 301 // aliasee. 302 auto &ValueInfo = CallGraphEdges[Index.getOrInsertValueInfo( 303 cast<GlobalValue>(CalledValue))]; 304 ValueInfo.updateHotness(Hotness); 305 // Add the relative block frequency to CalleeInfo if there is no profile 306 // information. 307 if (BFI != nullptr && Hotness == CalleeInfo::HotnessType::Unknown) { 308 uint64_t BBFreq = BFI->getBlockFreq(&BB).getFrequency(); 309 uint64_t EntryFreq = BFI->getEntryFreq(); 310 ValueInfo.updateRelBlockFreq(BBFreq, EntryFreq); 311 } 312 } else { 313 // Skip inline assembly calls. 314 if (CI && CI->isInlineAsm()) 315 continue; 316 // Skip direct calls. 317 if (!CalledValue || isa<Constant>(CalledValue)) 318 continue; 319 320 // Check if the instruction has a callees metadata. If so, add callees 321 // to CallGraphEdges to reflect the references from the metadata, and 322 // to enable importing for subsequent indirect call promotion and 323 // inlining. 324 if (auto *MD = I.getMetadata(LLVMContext::MD_callees)) { 325 for (auto &Op : MD->operands()) { 326 Function *Callee = mdconst::extract_or_null<Function>(Op); 327 if (Callee) 328 CallGraphEdges[Index.getOrInsertValueInfo(Callee)]; 329 } 330 } 331 332 uint32_t NumVals, NumCandidates; 333 uint64_t TotalCount; 334 auto CandidateProfileData = 335 ICallAnalysis.getPromotionCandidatesForInstruction( 336 &I, NumVals, TotalCount, NumCandidates); 337 for (auto &Candidate : CandidateProfileData) 338 CallGraphEdges[Index.getOrInsertValueInfo(Candidate.Value)] 339 .updateHotness(getHotness(Candidate.Count, PSI)); 340 } 341 } 342 343 // Explicit add hot edges to enforce importing for designated GUIDs for 344 // sample PGO, to enable the same inlines as the profiled optimized binary. 345 for (auto &I : F.getImportGUIDs()) 346 CallGraphEdges[Index.getOrInsertValueInfo(I)].updateHotness( 347 ForceSummaryEdgesCold == FunctionSummary::FSHT_All 348 ? CalleeInfo::HotnessType::Cold 349 : CalleeInfo::HotnessType::Critical); 350 351 bool NonRenamableLocal = isNonRenamableLocal(F); 352 bool NotEligibleForImport = 353 NonRenamableLocal || HasInlineAsmMaybeReferencingInternal || 354 // Inliner doesn't handle variadic functions. 355 // FIXME: refactor this to use the same code that inliner is using. 356 F.isVarArg() || 357 // Don't try to import functions with noinline attribute. 358 F.getAttributes().hasFnAttribute(Attribute::NoInline); 359 GlobalValueSummary::GVFlags Flags(F.getLinkage(), NotEligibleForImport, 360 /* Live = */ false, F.isDSOLocal()); 361 FunctionSummary::FFlags FunFlags{ 362 F.hasFnAttribute(Attribute::ReadNone), 363 F.hasFnAttribute(Attribute::ReadOnly), 364 F.hasFnAttribute(Attribute::NoRecurse), 365 F.returnDoesNotAlias(), 366 }; 367 auto FuncSummary = llvm::make_unique<FunctionSummary>( 368 Flags, NumInsts, FunFlags, RefEdges.takeVector(), 369 CallGraphEdges.takeVector(), TypeTests.takeVector(), 370 TypeTestAssumeVCalls.takeVector(), TypeCheckedLoadVCalls.takeVector(), 371 TypeTestAssumeConstVCalls.takeVector(), 372 TypeCheckedLoadConstVCalls.takeVector()); 373 if (NonRenamableLocal) 374 CantBePromoted.insert(F.getGUID()); 375 Index.addGlobalValueSummary(F, std::move(FuncSummary)); 376 } 377 378 static void 379 computeVariableSummary(ModuleSummaryIndex &Index, const GlobalVariable &V, 380 DenseSet<GlobalValue::GUID> &CantBePromoted) { 381 SetVector<ValueInfo> RefEdges; 382 SmallPtrSet<const User *, 8> Visited; 383 bool HasBlockAddress = findRefEdges(Index, &V, RefEdges, Visited); 384 bool NonRenamableLocal = isNonRenamableLocal(V); 385 GlobalValueSummary::GVFlags Flags(V.getLinkage(), NonRenamableLocal, 386 /* Live = */ false, V.isDSOLocal()); 387 auto GVarSummary = 388 llvm::make_unique<GlobalVarSummary>(Flags, RefEdges.takeVector()); 389 if (NonRenamableLocal) 390 CantBePromoted.insert(V.getGUID()); 391 if (HasBlockAddress) 392 GVarSummary->setNotEligibleToImport(); 393 Index.addGlobalValueSummary(V, std::move(GVarSummary)); 394 } 395 396 static void 397 computeAliasSummary(ModuleSummaryIndex &Index, const GlobalAlias &A, 398 DenseSet<GlobalValue::GUID> &CantBePromoted) { 399 bool NonRenamableLocal = isNonRenamableLocal(A); 400 GlobalValueSummary::GVFlags Flags(A.getLinkage(), NonRenamableLocal, 401 /* Live = */ false, A.isDSOLocal()); 402 auto AS = llvm::make_unique<AliasSummary>(Flags); 403 auto *Aliasee = A.getBaseObject(); 404 auto *AliaseeSummary = Index.getGlobalValueSummary(*Aliasee); 405 assert(AliaseeSummary && "Alias expects aliasee summary to be parsed"); 406 AS->setAliasee(AliaseeSummary); 407 if (NonRenamableLocal) 408 CantBePromoted.insert(A.getGUID()); 409 Index.addGlobalValueSummary(A, std::move(AS)); 410 } 411 412 // Set LiveRoot flag on entries matching the given value name. 413 static void setLiveRoot(ModuleSummaryIndex &Index, StringRef Name) { 414 if (ValueInfo VI = Index.getValueInfo(GlobalValue::getGUID(Name))) 415 for (auto &Summary : VI.getSummaryList()) 416 Summary->setLive(true); 417 } 418 419 ModuleSummaryIndex llvm::buildModuleSummaryIndex( 420 const Module &M, 421 std::function<BlockFrequencyInfo *(const Function &F)> GetBFICallback, 422 ProfileSummaryInfo *PSI) { 423 assert(PSI); 424 ModuleSummaryIndex Index(/*HaveGVs=*/true); 425 426 // Identify the local values in the llvm.used and llvm.compiler.used sets, 427 // which should not be exported as they would then require renaming and 428 // promotion, but we may have opaque uses e.g. in inline asm. We collect them 429 // here because we use this information to mark functions containing inline 430 // assembly calls as not importable. 431 SmallPtrSet<GlobalValue *, 8> LocalsUsed; 432 SmallPtrSet<GlobalValue *, 8> Used; 433 // First collect those in the llvm.used set. 434 collectUsedGlobalVariables(M, Used, /*CompilerUsed*/ false); 435 // Next collect those in the llvm.compiler.used set. 436 collectUsedGlobalVariables(M, Used, /*CompilerUsed*/ true); 437 DenseSet<GlobalValue::GUID> CantBePromoted; 438 for (auto *V : Used) { 439 if (V->hasLocalLinkage()) { 440 LocalsUsed.insert(V); 441 CantBePromoted.insert(V->getGUID()); 442 } 443 } 444 445 bool HasLocalInlineAsmSymbol = false; 446 if (!M.getModuleInlineAsm().empty()) { 447 // Collect the local values defined by module level asm, and set up 448 // summaries for these symbols so that they can be marked as NoRename, 449 // to prevent export of any use of them in regular IR that would require 450 // renaming within the module level asm. Note we don't need to create a 451 // summary for weak or global defs, as they don't need to be flagged as 452 // NoRename, and defs in module level asm can't be imported anyway. 453 // Also, any values used but not defined within module level asm should 454 // be listed on the llvm.used or llvm.compiler.used global and marked as 455 // referenced from there. 456 ModuleSymbolTable::CollectAsmSymbols( 457 M, [&](StringRef Name, object::BasicSymbolRef::Flags Flags) { 458 // Symbols not marked as Weak or Global are local definitions. 459 if (Flags & (object::BasicSymbolRef::SF_Weak | 460 object::BasicSymbolRef::SF_Global)) 461 return; 462 HasLocalInlineAsmSymbol = true; 463 GlobalValue *GV = M.getNamedValue(Name); 464 if (!GV) 465 return; 466 assert(GV->isDeclaration() && "Def in module asm already has definition"); 467 GlobalValueSummary::GVFlags GVFlags(GlobalValue::InternalLinkage, 468 /* NotEligibleToImport = */ true, 469 /* Live = */ true, 470 /* Local */ GV->isDSOLocal()); 471 CantBePromoted.insert(GV->getGUID()); 472 // Create the appropriate summary type. 473 if (Function *F = dyn_cast<Function>(GV)) { 474 std::unique_ptr<FunctionSummary> Summary = 475 llvm::make_unique<FunctionSummary>( 476 GVFlags, 0, 477 FunctionSummary::FFlags{ 478 F->hasFnAttribute(Attribute::ReadNone), 479 F->hasFnAttribute(Attribute::ReadOnly), 480 F->hasFnAttribute(Attribute::NoRecurse), 481 F->returnDoesNotAlias()}, 482 ArrayRef<ValueInfo>{}, ArrayRef<FunctionSummary::EdgeTy>{}, 483 ArrayRef<GlobalValue::GUID>{}, 484 ArrayRef<FunctionSummary::VFuncId>{}, 485 ArrayRef<FunctionSummary::VFuncId>{}, 486 ArrayRef<FunctionSummary::ConstVCall>{}, 487 ArrayRef<FunctionSummary::ConstVCall>{}); 488 Index.addGlobalValueSummary(*GV, std::move(Summary)); 489 } else { 490 std::unique_ptr<GlobalVarSummary> Summary = 491 llvm::make_unique<GlobalVarSummary>(GVFlags, 492 ArrayRef<ValueInfo>{}); 493 Index.addGlobalValueSummary(*GV, std::move(Summary)); 494 } 495 }); 496 } 497 498 // Compute summaries for all functions defined in module, and save in the 499 // index. 500 for (auto &F : M) { 501 if (F.isDeclaration()) 502 continue; 503 504 DominatorTree DT(const_cast<Function &>(F)); 505 BlockFrequencyInfo *BFI = nullptr; 506 std::unique_ptr<BlockFrequencyInfo> BFIPtr; 507 if (GetBFICallback) 508 BFI = GetBFICallback(F); 509 else if (F.hasProfileData()) { 510 LoopInfo LI{DT}; 511 BranchProbabilityInfo BPI{F, LI}; 512 BFIPtr = llvm::make_unique<BlockFrequencyInfo>(F, BPI, LI); 513 BFI = BFIPtr.get(); 514 } 515 516 computeFunctionSummary(Index, M, F, BFI, PSI, DT, 517 !LocalsUsed.empty() || HasLocalInlineAsmSymbol, 518 CantBePromoted); 519 } 520 521 // Compute summaries for all variables defined in module, and save in the 522 // index. 523 for (const GlobalVariable &G : M.globals()) { 524 if (G.isDeclaration()) 525 continue; 526 computeVariableSummary(Index, G, CantBePromoted); 527 } 528 529 // Compute summaries for all aliases defined in module, and save in the 530 // index. 531 for (const GlobalAlias &A : M.aliases()) 532 computeAliasSummary(Index, A, CantBePromoted); 533 534 for (auto *V : LocalsUsed) { 535 auto *Summary = Index.getGlobalValueSummary(*V); 536 assert(Summary && "Missing summary for global value"); 537 Summary->setNotEligibleToImport(); 538 } 539 540 // The linker doesn't know about these LLVM produced values, so we need 541 // to flag them as live in the index to ensure index-based dead value 542 // analysis treats them as live roots of the analysis. 543 setLiveRoot(Index, "llvm.used"); 544 setLiveRoot(Index, "llvm.compiler.used"); 545 setLiveRoot(Index, "llvm.global_ctors"); 546 setLiveRoot(Index, "llvm.global_dtors"); 547 setLiveRoot(Index, "llvm.global.annotations"); 548 549 bool IsThinLTO = true; 550 if (auto *MD = 551 mdconst::extract_or_null<ConstantInt>(M.getModuleFlag("ThinLTO"))) 552 IsThinLTO = MD->getZExtValue(); 553 554 for (auto &GlobalList : Index) { 555 // Ignore entries for references that are undefined in the current module. 556 if (GlobalList.second.SummaryList.empty()) 557 continue; 558 559 assert(GlobalList.second.SummaryList.size() == 1 && 560 "Expected module's index to have one summary per GUID"); 561 auto &Summary = GlobalList.second.SummaryList[0]; 562 if (!IsThinLTO) { 563 Summary->setNotEligibleToImport(); 564 continue; 565 } 566 567 bool AllRefsCanBeExternallyReferenced = 568 llvm::all_of(Summary->refs(), [&](const ValueInfo &VI) { 569 return !CantBePromoted.count(VI.getGUID()); 570 }); 571 if (!AllRefsCanBeExternallyReferenced) { 572 Summary->setNotEligibleToImport(); 573 continue; 574 } 575 576 if (auto *FuncSummary = dyn_cast<FunctionSummary>(Summary.get())) { 577 bool AllCallsCanBeExternallyReferenced = llvm::all_of( 578 FuncSummary->calls(), [&](const FunctionSummary::EdgeTy &Edge) { 579 return !CantBePromoted.count(Edge.first.getGUID()); 580 }); 581 if (!AllCallsCanBeExternallyReferenced) 582 Summary->setNotEligibleToImport(); 583 } 584 } 585 586 return Index; 587 } 588 589 AnalysisKey ModuleSummaryIndexAnalysis::Key; 590 591 ModuleSummaryIndex 592 ModuleSummaryIndexAnalysis::run(Module &M, ModuleAnalysisManager &AM) { 593 ProfileSummaryInfo &PSI = AM.getResult<ProfileSummaryAnalysis>(M); 594 auto &FAM = AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager(); 595 return buildModuleSummaryIndex( 596 M, 597 [&FAM](const Function &F) { 598 return &FAM.getResult<BlockFrequencyAnalysis>( 599 *const_cast<Function *>(&F)); 600 }, 601 &PSI); 602 } 603 604 char ModuleSummaryIndexWrapperPass::ID = 0; 605 606 INITIALIZE_PASS_BEGIN(ModuleSummaryIndexWrapperPass, "module-summary-analysis", 607 "Module Summary Analysis", false, true) 608 INITIALIZE_PASS_DEPENDENCY(BlockFrequencyInfoWrapperPass) 609 INITIALIZE_PASS_DEPENDENCY(ProfileSummaryInfoWrapperPass) 610 INITIALIZE_PASS_END(ModuleSummaryIndexWrapperPass, "module-summary-analysis", 611 "Module Summary Analysis", false, true) 612 613 ModulePass *llvm::createModuleSummaryIndexWrapperPass() { 614 return new ModuleSummaryIndexWrapperPass(); 615 } 616 617 ModuleSummaryIndexWrapperPass::ModuleSummaryIndexWrapperPass() 618 : ModulePass(ID) { 619 initializeModuleSummaryIndexWrapperPassPass(*PassRegistry::getPassRegistry()); 620 } 621 622 bool ModuleSummaryIndexWrapperPass::runOnModule(Module &M) { 623 auto &PSI = *getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI(); 624 Index.emplace(buildModuleSummaryIndex( 625 M, 626 [this](const Function &F) { 627 return &(this->getAnalysis<BlockFrequencyInfoWrapperPass>( 628 *const_cast<Function *>(&F)) 629 .getBFI()); 630 }, 631 &PSI)); 632 return false; 633 } 634 635 bool ModuleSummaryIndexWrapperPass::doFinalization(Module &M) { 636 Index.reset(); 637 return false; 638 } 639 640 void ModuleSummaryIndexWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const { 641 AU.setPreservesAll(); 642 AU.addRequired<BlockFrequencyInfoWrapperPass>(); 643 AU.addRequired<ProfileSummaryInfoWrapperPass>(); 644 } 645