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//===- ReduceDIMetadata.cpp - Specialized Delta pass for DebugInfo --------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file implements two functions used by the Generic Delta Debugging
// Algorithm, which are used to reduce DebugInfo metadata nodes.
//
//===----------------------------------------------------------------------===//
#include "ReduceDIMetadata.h"
#include "Delta.h"
#include "llvm/ADT/Sequence.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/InstIterator.h"
#include <set>
#include <stack>
#include <tuple>
#include <vector>
using namespace llvm;
using MDNodeList = SmallVector<MDNode *>;
void identifyUninterestingMDNodes(Oracle &O, MDNodeList &MDs) {
SetVector<std::tuple<MDNode *, size_t, MDNode *>> Tuples;
std::vector<MDNode *> ToLook;
SetVector<MDNode *> Visited;
// Start by looking at the attachments we collected
for (const auto &NMD : MDs)
if (NMD)
ToLook.push_back(NMD);
while (!ToLook.empty()) {
MDNode *MD = ToLook.back();
ToLook.pop_back();
if (Visited.count(MD))
continue;
// Determine if the current MDNode is DebugInfo
if (DINode *DIM = dyn_cast_or_null<DINode>(MD)) {
// Scan operands and record attached tuples
for (size_t I = 0; I < DIM->getNumOperands(); ++I)
if (MDTuple *MDT = dyn_cast_or_null<MDTuple>(DIM->getOperand(I)))
if (!Visited.count(MDT) && MDT->getNumOperands())
Tuples.insert({DIM, I, MDT});
}
// Add all of the operands of the current node to the loop's todo list.
for (Metadata *Op : MD->operands())
if (MDNode *OMD = dyn_cast_or_null<MDNode>(Op))
ToLook.push_back(OMD);
Visited.insert(MD);
}
for (auto &T : Tuples) {
auto [DbgNode, OpIdx, Tup] = T;
// Remove the operands of the tuple that are not in the desired chunks.
SmallVector<Metadata *, 16> TN;
for (size_t I = 0; I < Tup->getNumOperands(); ++I) {
// Ignore any operands that are not DebugInfo metadata nodes.
if (isa_and_nonnull<DINode>(Tup->getOperand(I)))
// Don't add uninteresting operands to the tuple.
if (!O.shouldKeep())
continue;
TN.push_back(Tup->getOperand(I));
}
if (TN.size() != Tup->getNumOperands())
DbgNode->replaceOperandWith(OpIdx, DbgNode->get(DbgNode->getContext(), TN));
}
}
static void extractDIMetadataFromModule(Oracle &O, ReducerWorkItem &WorkItem) {
Module &Program = WorkItem.getModule();
MDNodeList MDs;
// Collect all !dbg metadata attachments.
for (const auto &DC : Program.debug_compile_units())
if (DC)
MDs.push_back(DC);
for (GlobalVariable &GV : Program.globals())
GV.getMetadata(llvm::LLVMContext::MD_dbg, MDs);
for (Function &F : Program.functions()) {
F.getMetadata(llvm::LLVMContext::MD_dbg, MDs);
for (Instruction &I : instructions(F))
if (auto *DI = I.getMetadata(llvm::LLVMContext::MD_dbg))
MDs.push_back(DI);
}
identifyUninterestingMDNodes(O, MDs);
}
void llvm::reduceDIMetadataDeltaPass(TestRunner &Test) {
runDeltaPass(Test, extractDIMetadataFromModule, "Reducing DIMetadata");
}
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