diff options
| -rw-r--r-- | llvm/include/llvm/Analysis/ModuleSummaryAnalysis.h | 5 | ||||
| -rw-r--r-- | llvm/include/llvm/IR/ModuleSummaryIndex.h | 4 | ||||
| -rw-r--r-- | llvm/lib/Analysis/ModuleSummaryAnalysis.cpp | 76 | ||||
| -rw-r--r-- | llvm/lib/Transforms/Utils/FunctionImportUtils.cpp | 8 |
4 files changed, 34 insertions, 59 deletions
diff --git a/llvm/include/llvm/Analysis/ModuleSummaryAnalysis.h b/llvm/include/llvm/Analysis/ModuleSummaryAnalysis.h index c8adc3bf81a..617c3d8f17a 100644 --- a/llvm/include/llvm/Analysis/ModuleSummaryAnalysis.h +++ b/llvm/include/llvm/Analysis/ModuleSummaryAnalysis.h @@ -70,11 +70,6 @@ public: // object for the module, to be written to bitcode or LLVM assembly. // ModulePass *createModuleSummaryIndexWrapperPass(); - -/// Returns true if \p M is eligible for ThinLTO promotion. -/// -/// Currently we check if it has any any InlineASM that uses an internal symbol. -bool moduleCanBeRenamedForThinLTO(const Module &M); } #endif diff --git a/llvm/include/llvm/IR/ModuleSummaryIndex.h b/llvm/include/llvm/IR/ModuleSummaryIndex.h index 1ceb9eb32cb..b3775904e75 100644 --- a/llvm/include/llvm/IR/ModuleSummaryIndex.h +++ b/llvm/include/llvm/IR/ModuleSummaryIndex.h @@ -194,6 +194,10 @@ public: /// possibly referenced from inline assembly, etc). bool noRename() const { return Flags.NoRename; } + /// Flag that this global value cannot be renamed (in a specific section, + /// possibly referenced from inline assembly, etc). + void setNoRename() { Flags.NoRename = true; } + /// Record a reference from this global value to the global value identified /// by \p RefGUID. void addRefEdge(GlobalValue::GUID RefGUID) { RefEdgeList.push_back(RefGUID); } diff --git a/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp b/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp index f13ae844442..09d18eb3da1 100644 --- a/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp +++ b/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp @@ -77,7 +77,8 @@ static CalleeInfo::HotnessType getHotness(uint64_t ProfileCount, static void computeFunctionSummary(ModuleSummaryIndex &Index, const Module &M, const Function &F, BlockFrequencyInfo *BFI, - ProfileSummaryInfo *PSI) { + ProfileSummaryInfo *PSI, + SmallPtrSetImpl<GlobalValue *> &LocalsUsed) { // Summary not currently supported for anonymous functions, they should // have been named. assert(F.hasName()); @@ -89,6 +90,7 @@ static void computeFunctionSummary(ModuleSummaryIndex &Index, const Module &M, DenseMap<GlobalValue::GUID, CalleeInfo> IndirectCallEdges; DenseSet<const Value *> RefEdges; ICallPromotionAnalysis ICallAnalysis; + bool HasLocalsInUsed = !LocalsUsed.empty(); SmallPtrSet<const User *, 8> Visited; for (const BasicBlock &BB : F) @@ -100,6 +102,15 @@ static void computeFunctionSummary(ModuleSummaryIndex &Index, const Module &M, auto CS = ImmutableCallSite(&I); if (!CS) continue; + + const auto *CI = dyn_cast<CallInst>(&I); + // Since we don't know exactly which local values are referenced in inline + // assembly, conservatively reference all of them from this function, to + // ensure we don't export a reference (which would require renaming and + // promotion). + if (HasLocalsInUsed && CI && CI->isInlineAsm()) + RefEdges.insert(LocalsUsed.begin(), LocalsUsed.end()); + auto *CalledValue = CS.getCalledValue(); auto *CalledFunction = CS.getCalledFunction(); // Check if this is an alias to a function. If so, get the @@ -127,7 +138,6 @@ static void computeFunctionSummary(ModuleSummaryIndex &Index, const Module &M, : CalleeInfo::HotnessType::Unknown; CallGraphEdges[CalleeId].updateHotness(Hotness); } else { - const auto *CI = dyn_cast<CallInst>(&I); // Skip inline assembly calls. if (CI && CI->isInlineAsm()) continue; @@ -183,11 +193,17 @@ ModuleSummaryIndex llvm::buildModuleSummaryIndex( std::function<BlockFrequencyInfo *(const Function &F)> GetBFICallback, ProfileSummaryInfo *PSI) { ModuleSummaryIndex Index; - // Check if the module can be promoted, otherwise just disable importing from - // it by not emitting any summary. - // FIXME: we could still import *into* it most of the time. - if (!moduleCanBeRenamedForThinLTO(M)) - return Index; + + // Identify the local values in the llvm.used set, which should not be + // exported as they would then require renaming and promotion, but we + // may have opaque uses e.g. in inline asm. + SmallPtrSet<GlobalValue *, 8> Used; + collectUsedGlobalVariables(M, Used, /*CompilerUsed*/ false); + SmallPtrSet<GlobalValue *, 8> LocalsUsed; + for (auto *V : Used) { + if (V->hasLocalLinkage()) + LocalsUsed.insert(V); + } // Compute summaries for all functions defined in module, and save in the // index. @@ -206,7 +222,7 @@ ModuleSummaryIndex llvm::buildModuleSummaryIndex( BFI = BFIPtr.get(); } - computeFunctionSummary(Index, M, F, BFI, PSI); + computeFunctionSummary(Index, M, F, BFI, PSI, LocalsUsed); } // Compute summaries for all variables defined in module, and save in the @@ -222,6 +238,12 @@ ModuleSummaryIndex llvm::buildModuleSummaryIndex( for (const GlobalAlias &A : M.aliases()) computeAliasSummary(Index, A); + for (auto *V : LocalsUsed) { + auto *Summary = Index.getGlobalValueSummary(*V); + assert(Summary && "Missing summary for global value"); + Summary->setNoRename(); + } + return Index; } @@ -279,41 +301,3 @@ void ModuleSummaryIndexWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const { AU.addRequired<BlockFrequencyInfoWrapperPass>(); AU.addRequired<ProfileSummaryInfoWrapperPass>(); } - -bool llvm::moduleCanBeRenamedForThinLTO(const Module &M) { - // We cannot currently promote or rename anything used in inline assembly, - // which are not visible to the compiler. Detect a possible case by looking - // for a llvm.used local value, in conjunction with an inline assembly call - // in the module. Prevent importing of any modules containing these uses by - // suppressing generation of the index. This also prevents importing - // into this module, which is also necessary to avoid needing to rename - // in case of a name clash between a local in this module and an imported - // global. - // FIXME: If we find we need a finer-grained approach of preventing promotion - // and renaming of just the functions using inline assembly we will need to: - // - Add flag in the function summaries to identify those with inline asm. - // - Prevent importing of any functions with flag set. - // - Prevent importing of any global function with the same name as a - // function in current module that has the flag set. - // - For any llvm.used value that is exported and promoted, add a private - // alias to the original name in the current module (even if we don't - // export the function using those values in inline asm, another function - // with a reference could be exported). - SmallPtrSet<GlobalValue *, 8> Used; - collectUsedGlobalVariables(M, Used, /*CompilerUsed*/ false); - bool LocalIsUsed = - any_of(Used, [](GlobalValue *V) { return V->hasLocalLinkage(); }); - if (!LocalIsUsed) - return true; - - // Walk all the instructions in the module and find if one is inline ASM - auto HasInlineAsm = any_of(M, [](const Function &F) { - return any_of(instructions(F), [](const Instruction &I) { - const CallInst *CallI = dyn_cast<CallInst>(&I); - if (!CallI) - return false; - return CallI->isInlineAsm(); - }); - }); - return !HasInlineAsm; -} diff --git a/llvm/lib/Transforms/Utils/FunctionImportUtils.cpp b/llvm/lib/Transforms/Utils/FunctionImportUtils.cpp index d14920575a4..b9b3606ecfb 100644 --- a/llvm/lib/Transforms/Utils/FunctionImportUtils.cpp +++ b/llvm/lib/Transforms/Utils/FunctionImportUtils.cpp @@ -220,14 +220,6 @@ void FunctionImportGlobalProcessing::processGlobalForThinLTO(GlobalValue &GV) { } void FunctionImportGlobalProcessing::processGlobalsForThinLTO() { - if (!moduleCanBeRenamedForThinLTO(M)) { - // We would have blocked importing from this module by suppressing index - // generation. We still may be able to import into this module though. - assert(!isPerformingImport() && - "Should have blocked importing from module with local used in ASM"); - return; - } - for (GlobalVariable &GV : M.globals()) processGlobalForThinLTO(GV); for (Function &SF : M) |
