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/Transforms/Utils/BuildLibCalls.h" 14 #include "llvm/Transforms/Utils/Local.h" 15 using namespace llvm; 16 17 #define DEBUG_TYPE "inferattrs" 18 19 static bool inferAllPrototypeAttributes( 20 Module &M, function_ref<TargetLibraryInfo &(Function &)> GetTLI) { 21 bool Changed = false; 22 23 for (Function &F : M.functions()) 24 // We only infer things using the prototype and the name; we don't need 25 // definitions. This ensures libfuncs are annotated and also allows our 26 // CGSCC inference to avoid needing to duplicate the inference from other 27 // attribute logic on all calls to declarations (as declarations aren't 28 // explicitly visited by CGSCC passes in the new pass manager.) 29 if (F.isDeclaration() && !F.hasOptNone()) { 30 if (!F.hasFnAttribute(Attribute::NoBuiltin)) 31 Changed |= inferNonMandatoryLibFuncAttrs(F, GetTLI(F)); 32 Changed |= inferAttributesFromOthers(F); 33 } 34 35 return Changed; 36 } 37 38 PreservedAnalyses InferFunctionAttrsPass::run(Module &M, 39 ModuleAnalysisManager &AM) { 40 FunctionAnalysisManager &FAM = 41 AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager(); 42 auto GetTLI = [&FAM](Function &F) -> TargetLibraryInfo & { 43 return FAM.getResult<TargetLibraryAnalysis>(F); 44 }; 45 46 if (!inferAllPrototypeAttributes(M, GetTLI)) 47 // If we didn't infer anything, preserve all analyses. 48 return PreservedAnalyses::all(); 49 50 // Otherwise, we may have changed fundamental function attributes, so clear 51 // out all the passes. 52 return PreservedAnalyses::none(); 53 } 54