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
inferAllPrototypeAttributes(Module & M,const TargetLibraryInfo & TLI)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
run(Module & M,AnalysisManager<Module> & AM)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
InferFunctionAttrsLegacyPass__anon4fe2bd6e0111::InferFunctionAttrsLegacyPass52 InferFunctionAttrsLegacyPass() : ModulePass(ID) {
53 initializeInferFunctionAttrsLegacyPassPass(
54 *PassRegistry::getPassRegistry());
55 }
56
getAnalysisUsage__anon4fe2bd6e0111::InferFunctionAttrsLegacyPass57 void getAnalysisUsage(AnalysisUsage &AU) const override {
58 AU.addRequired<TargetLibraryInfoWrapperPass>();
59 }
60
runOnModule__anon4fe2bd6e0111::InferFunctionAttrsLegacyPass61 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)
INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)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 }
81