xref: /freebsd/contrib/llvm-project/llvm/lib/Transforms/IPO/InferFunctionAttrs.cpp (revision c66ec88fed842fbaad62c30d510644ceb7bd2d71)
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 }
86