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 #include "llvm/Transforms/Utils/Local.h"
19 using namespace llvm;
20
21 #define DEBUG_TYPE "inferattrs"
22
inferAllPrototypeAttributes(Module & M,function_ref<TargetLibraryInfo & (Function &)> GetTLI)23 static bool inferAllPrototypeAttributes(
24 Module &M, function_ref<TargetLibraryInfo &(Function &)> GetTLI) {
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. This ensures libfuncs are annotated and also allows our
30 // CGSCC inference to avoid needing to duplicate the inference from other
31 // attribute logic on all calls to declarations (as declarations aren't
32 // explicitly visited by CGSCC passes in the new pass manager.)
33 if (F.isDeclaration() && !F.hasOptNone()) {
34 if (!F.hasFnAttribute(Attribute::NoBuiltin))
35 Changed |= inferLibFuncAttributes(F, GetTLI(F));
36 Changed |= inferAttributesFromOthers(F);
37 }
38
39 return Changed;
40 }
41
run(Module & M,ModuleAnalysisManager & AM)42 PreservedAnalyses InferFunctionAttrsPass::run(Module &M,
43 ModuleAnalysisManager &AM) {
44 FunctionAnalysisManager &FAM =
45 AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
46 auto GetTLI = [&FAM](Function &F) -> TargetLibraryInfo & {
47 return FAM.getResult<TargetLibraryAnalysis>(F);
48 };
49
50 if (!inferAllPrototypeAttributes(M, GetTLI))
51 // If we didn't infer anything, preserve all analyses.
52 return PreservedAnalyses::all();
53
54 // Otherwise, we may have changed fundamental function attributes, so clear
55 // out all the passes.
56 return PreservedAnalyses::none();
57 }
58
59 namespace {
60 struct InferFunctionAttrsLegacyPass : public ModulePass {
61 static char ID; // Pass identification, replacement for typeid
InferFunctionAttrsLegacyPass__anona48290d80211::InferFunctionAttrsLegacyPass62 InferFunctionAttrsLegacyPass() : ModulePass(ID) {
63 initializeInferFunctionAttrsLegacyPassPass(
64 *PassRegistry::getPassRegistry());
65 }
66
getAnalysisUsage__anona48290d80211::InferFunctionAttrsLegacyPass67 void getAnalysisUsage(AnalysisUsage &AU) const override {
68 AU.addRequired<TargetLibraryInfoWrapperPass>();
69 }
70
runOnModule__anona48290d80211::InferFunctionAttrsLegacyPass71 bool runOnModule(Module &M) override {
72 if (skipModule(M))
73 return false;
74
75 auto GetTLI = [this](Function &F) -> TargetLibraryInfo & {
76 return this->getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F);
77 };
78 return inferAllPrototypeAttributes(M, GetTLI);
79 }
80 };
81 }
82
83 char InferFunctionAttrsLegacyPass::ID = 0;
84 INITIALIZE_PASS_BEGIN(InferFunctionAttrsLegacyPass, "inferattrs",
85 "Infer set function attributes", false, false)
INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)86 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
87 INITIALIZE_PASS_END(InferFunctionAttrsLegacyPass, "inferattrs",
88 "Infer set function attributes", false, false)
89
90 Pass *llvm::createInferFunctionAttrsLegacyPass() {
91 return new InferFunctionAttrsLegacyPass();
92 }
93