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 #include "llvm/InitializePasses.h"
21 #include "llvm/Pass.h"
22 #include "llvm/Transforms/IPO.h"
23
24 using namespace llvm;
25
26 #define DEBUG_TYPE "annotation2metadata"
27
convertAnnotation2Metadata(Module & M)28 static bool convertAnnotation2Metadata(Module &M) {
29 // Only add !annotation metadata if the corresponding remarks pass is also
30 // enabled.
31 if (!OptimizationRemarkEmitter::allowExtraAnalysis(M.getContext(),
32 "annotation-remarks"))
33 return false;
34
35 auto *Annotations = M.getGlobalVariable("llvm.global.annotations");
36 auto *C = dyn_cast_or_null<Constant>(Annotations);
37 if (!C || C->getNumOperands() != 1)
38 return false;
39
40 C = cast<Constant>(C->getOperand(0));
41
42 // Iterate over all entries in C and attach !annotation metadata to suitable
43 // entries.
44 for (auto &Op : C->operands()) {
45 // Look at the operands to check if we can use the entry to generate
46 // !annotation metadata.
47 auto *OpC = dyn_cast<ConstantStruct>(&Op);
48 if (!OpC || OpC->getNumOperands() != 4)
49 continue;
50 auto *StrGEP = dyn_cast<ConstantExpr>(OpC->getOperand(1));
51 if (!StrGEP || StrGEP->getNumOperands() < 2)
52 continue;
53 auto *StrC = dyn_cast<GlobalValue>(StrGEP->getOperand(0));
54 if (!StrC)
55 continue;
56 auto *StrData = dyn_cast<ConstantDataSequential>(StrC->getOperand(0));
57 if (!StrData)
58 continue;
59 // Look through bitcast.
60 auto *Bitcast = dyn_cast<ConstantExpr>(OpC->getOperand(0));
61 if (!Bitcast || Bitcast->getOpcode() != Instruction::BitCast)
62 continue;
63 auto *Fn = dyn_cast<Function>(Bitcast->getOperand(0));
64 if (!Fn)
65 continue;
66
67 // Add annotation to all instructions in the function.
68 for (auto &I : instructions(Fn))
69 I.addAnnotationMetadata(StrData->getAsCString());
70 }
71 return true;
72 }
73
74 namespace {
75 struct Annotation2MetadataLegacy : public ModulePass {
76 static char ID;
77
Annotation2MetadataLegacy__anon7c07680e0111::Annotation2MetadataLegacy78 Annotation2MetadataLegacy() : ModulePass(ID) {
79 initializeAnnotation2MetadataLegacyPass(*PassRegistry::getPassRegistry());
80 }
81
runOnModule__anon7c07680e0111::Annotation2MetadataLegacy82 bool runOnModule(Module &M) override { return convertAnnotation2Metadata(M); }
83
getAnalysisUsage__anon7c07680e0111::Annotation2MetadataLegacy84 void getAnalysisUsage(AnalysisUsage &AU) const override {
85 AU.setPreservesAll();
86 }
87 };
88
89 } // end anonymous namespace
90
91 char Annotation2MetadataLegacy::ID = 0;
92
93 INITIALIZE_PASS_BEGIN(Annotation2MetadataLegacy, DEBUG_TYPE,
94 "Annotation2Metadata", false, false)
95 INITIALIZE_PASS_END(Annotation2MetadataLegacy, DEBUG_TYPE,
96 "Annotation2Metadata", false, false)
97
createAnnotation2MetadataLegacyPass()98 ModulePass *llvm::createAnnotation2MetadataLegacyPass() {
99 return new Annotation2MetadataLegacy();
100 }
101
run(Module & M,ModuleAnalysisManager & AM)102 PreservedAnalyses Annotation2MetadataPass::run(Module &M,
103 ModuleAnalysisManager &AM) {
104 convertAnnotation2Metadata(M);
105 return PreservedAnalyses::all();
106 }
107