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/Module.h"
13#include "llvm/InitializePasses.h"
14#include "llvm/Transforms/Utils/BuildLibCalls.h"
15#include "llvm/Transforms/Utils/Local.h"
16using namespace llvm;
17
18#define DEBUG_TYPE "inferattrs"
19
20static bool inferAllPrototypeAttributes(
21 Module &M, function_ref<TargetLibraryInfo &(Function &)> GetTLI) {
22 bool Changed = false;
23
24 for (Function &F : M.functions())
25 // We only infer things using the prototype and the name; we don't need
26 // definitions. This ensures libfuncs are annotated and also allows our
27 // CGSCC inference to avoid needing to duplicate the inference from other
28 // attribute logic on all calls to declarations (as declarations aren't
29 // explicitly visited by CGSCC passes in the new pass manager.)
30 if (F.isDeclaration() && !F.hasOptNone()) {
31 if (!F.hasFnAttribute(Attribute::NoBuiltin))
32 Changed |= inferNonMandatoryLibFuncAttrs(F, GetTLI(F));
33 Changed |= inferAttributesFromOthers(F);
34 }
35
36 return Changed;
37}
38
39PreservedAnalyses InferFunctionAttrsPass::run(Module &M,
40 ModuleAnalysisManager &AM) {
41 FunctionAnalysisManager &FAM =
42 AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
43 auto GetTLI = [&FAM](Function &F) -> TargetLibraryInfo & {
44 return FAM.getResult<TargetLibraryAnalysis>(F);
45 };
46
47 if (!inferAllPrototypeAttributes(M, GetTLI))
48 // If we didn't infer anything, preserve all analyses.
49 return PreservedAnalyses::all();
50
51 // Otherwise, we may have changed fundamental function attributes, so clear
52 // out all the passes.
53 return PreservedAnalyses::none();
54}
55
56namespace {
57struct InferFunctionAttrsLegacyPass : public ModulePass {
58 static char ID; // Pass identification, replacement for typeid
59 InferFunctionAttrsLegacyPass() : ModulePass(ID) {
60 initializeInferFunctionAttrsLegacyPassPass(
61 *PassRegistry::getPassRegistry());
62 }
63
64 void getAnalysisUsage(AnalysisUsage &AU) const override {
65 AU.addRequired<TargetLibraryInfoWrapperPass>();
66 }
67
68 bool runOnModule(Module &M) override {
69 if (skipModule(M))
70 return false;
71
72 auto GetTLI = [this](Function &F) -> TargetLibraryInfo & {
73 return this->getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F);
74 };
75 return inferAllPrototypeAttributes(M, GetTLI);
76 }
77};
78}
79
80char InferFunctionAttrsLegacyPass::ID = 0;
81INITIALIZE_PASS_BEGIN(InferFunctionAttrsLegacyPass, "inferattrs",
82 "Infer set function attributes", false, false)
83INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
84INITIALIZE_PASS_END(InferFunctionAttrsLegacyPass, "inferattrs",
85 "Infer set function attributes", false, false)
86
87Pass *llvm::createInferFunctionAttrsLegacyPass() {
88 return new InferFunctionAttrsLegacyPass();
89}
90

source code of llvm/lib/Transforms/IPO/InferFunctionAttrs.cpp