contrib/llvm-project/llvm/lib/Transforms/IPO/InferFunctionAttrs.cpp

   1 //===- InferFunctionAttrs.cpp - Infer implicit function attributes --------===//
   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 #include "llvm/Transforms/IPO/InferFunctionAttrs.h"
  10 #include "llvm/Analysis/TargetLibraryInfo.h"
  11 #include "llvm/IR/Function.h"
  12 #include "llvm/IR/LLVMContext.h"
  13 #include "llvm/IR/Module.h"
  14 #include "llvm/InitializePasses.h"
  15 #include "llvm/Support/Debug.h"
  16 #include "llvm/Support/raw_ostream.h"
  17 #include "llvm/Transforms/Utils/BuildLibCalls.h"
  18 using namespace llvm;
  19
  20 #define DEBUG_TYPE "inferattrs"
  21
  22 static bool inferAllPrototypeAttributes(
  23     Module &M, function_ref<TargetLibraryInfo &(Function &)> GetTLI) {
  24   bool Changed = false;
  25
  26   for (Function &F : M.functions())
  27     // We only infer things using the prototype and the name; we don't need
  28     // definitions.
  29     if (F.isDeclaration() && !F.hasOptNone())
  30       Changed |= inferLibFuncAttributes(F, GetTLI(F));
  31
  32   return Changed;
  33 }
  34
  35 PreservedAnalyses InferFunctionAttrsPass::run(Module &M,
  36                                               ModuleAnalysisManager &AM) {
  37   FunctionAnalysisManager &FAM =
  38       AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
  39   auto GetTLI = [&FAM](Function &F) -> TargetLibraryInfo & {
  40     return FAM.getResult<TargetLibraryAnalysis>(F);
  41   };
  42
  43   if (!inferAllPrototypeAttributes(M, GetTLI))
  44     // If we didn't infer anything, preserve all analyses.
  45     return PreservedAnalyses::all();
  46
  47   // Otherwise, we may have changed fundamental function attributes, so clear
  48   // out all the passes.
  49   return PreservedAnalyses::none();
  50 }
  51
  52 namespace {
  53 struct InferFunctionAttrsLegacyPass : public ModulePass {
  54   static char ID; // Pass identification, replacement for typeid
  55   InferFunctionAttrsLegacyPass() : ModulePass(ID) {
  56     initializeInferFunctionAttrsLegacyPassPass(
  57         *PassRegistry::getPassRegistry());
  58   }
  59
  60   void getAnalysisUsage(AnalysisUsage &AU) const override {
  61     AU.addRequired<TargetLibraryInfoWrapperPass>();
  62   }
  63
  64   bool runOnModule(Module &M) override {
  65     if (skipModule(M))
  66       return false;
  67
  68     auto GetTLI = [this](Function &F) -> TargetLibraryInfo & {
  69       return this->getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F);
  70     };
  71     return inferAllPrototypeAttributes(M, GetTLI);
  72   }
  73 };
  74 }
  75
  76 char InferFunctionAttrsLegacyPass::ID = 0;
  77 INITIALIZE_PASS_BEGIN(InferFunctionAttrsLegacyPass, "inferattrs",
  78                       "Infer set function attributes", false, false)
  79 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
  80 INITIALIZE_PASS_END(InferFunctionAttrsLegacyPass, "inferattrs",
  81                     "Infer set function attributes", false, false)
  82
  83 Pass *llvm::createInferFunctionAttrsLegacyPass() {
  84   return new InferFunctionAttrsLegacyPass();
  85 }