1 //===-- Annotation2Metadata.cpp - Add !annotation metadata. ---------------===// 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 // Add !annotation metadata for entries in @llvm.global.anotations, generated 10 // using __attribute__((annotate("_name"))) on functions in Clang. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/Transforms/IPO/Annotation2Metadata.h" 15 #include "llvm/Analysis/OptimizationRemarkEmitter.h" 16 #include "llvm/IR/Constants.h" 17 #include "llvm/IR/Function.h" 18 #include "llvm/IR/InstIterator.h" 19 #include "llvm/IR/Module.h" 20 21 using namespace llvm; 22 23 #define DEBUG_TYPE "annotation2metadata" 24 25 static bool convertAnnotation2Metadata(Module &M) { 26 // Only add !annotation metadata if the corresponding remarks pass is also 27 // enabled. 28 if (!OptimizationRemarkEmitter::allowExtraAnalysis(M.getContext(), 29 "annotation-remarks")) 30 return false; 31 32 auto *Annotations = M.getGlobalVariable("llvm.global.annotations"); 33 auto *C = dyn_cast_or_null<Constant>(Annotations); 34 if (!C || C->getNumOperands() != 1) 35 return false; 36 37 C = cast<Constant>(C->getOperand(0)); 38 39 // Iterate over all entries in C and attach !annotation metadata to suitable 40 // entries. 41 for (auto &Op : C->operands()) { 42 // Look at the operands to check if we can use the entry to generate 43 // !annotation metadata. 44 auto *OpC = dyn_cast<ConstantStruct>(&Op); 45 if (!OpC || OpC->getNumOperands() != 4) 46 continue; 47 auto *StrC = dyn_cast<GlobalValue>(OpC->getOperand(1)->stripPointerCasts()); 48 if (!StrC) 49 continue; 50 auto *StrData = dyn_cast<ConstantDataSequential>(StrC->getOperand(0)); 51 if (!StrData) 52 continue; 53 auto *Fn = dyn_cast<Function>(OpC->getOperand(0)->stripPointerCasts()); 54 if (!Fn) 55 continue; 56 57 // Add annotation to all instructions in the function. 58 for (auto &I : instructions(Fn)) 59 I.addAnnotationMetadata(StrData->getAsCString()); 60 } 61 return true; 62 } 63 64 PreservedAnalyses Annotation2MetadataPass::run(Module &M, 65 ModuleAnalysisManager &AM) { 66 return convertAnnotation2Metadata(M) ? PreservedAnalyses::none() 67 : PreservedAnalyses::all(); 68 } 69