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

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