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//===-- Annotation2Metadata.cpp - Add !annotation metadata. ---------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Add !annotation metadata for entries in @llvm.global.anotations, generated
// using __attribute__((annotate("_name"))) on functions in Clang.
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/IPO/Annotation2Metadata.h"
#include "llvm/Analysis/OptimizationRemarkEmitter.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/Module.h"
#include "llvm/Transforms/IPO.h"
using namespace llvm;
#define DEBUG_TYPE "annotation2metadata"
static bool convertAnnotation2Metadata(Module &M) {
// Only add !annotation metadata if the corresponding remarks pass is also
// enabled.
if (!OptimizationRemarkEmitter::allowExtraAnalysis(M.getContext(),
"annotation-remarks"))
return false;
auto *Annotations = M.getGlobalVariable("llvm.global.annotations");
auto *C = dyn_cast_or_null<Constant>(Annotations);
if (!C || C->getNumOperands() != 1)
return false;
C = cast<Constant>(C->getOperand(0));
// Iterate over all entries in C and attach !annotation metadata to suitable
// entries.
for (auto &Op : C->operands()) {
// Look at the operands to check if we can use the entry to generate
// !annotation metadata.
auto *OpC = dyn_cast<ConstantStruct>(&Op);
if (!OpC || OpC->getNumOperands() != 4)
continue;
auto *StrC = dyn_cast<GlobalValue>(OpC->getOperand(1)->stripPointerCasts());
if (!StrC)
continue;
auto *StrData = dyn_cast<ConstantDataSequential>(StrC->getOperand(0));
if (!StrData)
continue;
auto *Fn = dyn_cast<Function>(OpC->getOperand(0)->stripPointerCasts());
if (!Fn)
continue;
// Add annotation to all instructions in the function.
for (auto &I : instructions(Fn))
I.addAnnotationMetadata(StrData->getAsCString());
}
return true;
}
PreservedAnalyses Annotation2MetadataPass::run(Module &M,
ModuleAnalysisManager &AM) {
return convertAnnotation2Metadata(M) ? PreservedAnalyses::none()
: PreservedAnalyses::all();
}
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