1 //===- ReduceDIMetadata.cpp - Specialized Delta pass for DebugInfo --------===//
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 // This file implements two functions used by the Generic Delta Debugging
10 // Algorithm, which are used to reduce DebugInfo metadata nodes.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "ReduceDIMetadata.h"
15 #include "Delta.h"
16 #include "llvm/ADT/Sequence.h"
17 #include "llvm/ADT/SetVector.h"
18 #include "llvm/ADT/SmallSet.h"
19 #include "llvm/ADT/SmallVector.h"
20 #include "llvm/IR/DebugInfoMetadata.h"
21 #include "llvm/IR/InstIterator.h"
22 #include <set>
23 #include <stack>
24 #include <tuple>
25 #include <vector>
26
27 using namespace llvm;
28
29 using MDNodeList = SmallVector<MDNode *>;
30
identifyUninterestingMDNodes(Oracle & O,MDNodeList & MDs)31 void identifyUninterestingMDNodes(Oracle &O, MDNodeList &MDs) {
32 SetVector<std::tuple<MDNode *, size_t, MDNode *>> Tuples;
33 std::vector<MDNode *> ToLook;
34 SetVector<MDNode *> Visited;
35
36 // Start by looking at the attachments we collected
37 for (const auto &NMD : MDs)
38 if (NMD)
39 ToLook.push_back(NMD);
40
41 while (!ToLook.empty()) {
42 MDNode *MD = ToLook.back();
43 ToLook.pop_back();
44
45 if (Visited.count(MD))
46 continue;
47
48 // Determine if the current MDNode is DebugInfo
49 if (DINode *DIM = dyn_cast_or_null<DINode>(MD)) {
50 // Scan operands and record attached tuples
51 for (size_t I = 0; I < DIM->getNumOperands(); ++I)
52 if (MDTuple *MDT = dyn_cast_or_null<MDTuple>(DIM->getOperand(I)))
53 if (!Visited.count(MDT) && MDT->getNumOperands())
54 Tuples.insert({DIM, I, MDT});
55 }
56
57 // Add all of the operands of the current node to the loop's todo list.
58 for (Metadata *Op : MD->operands())
59 if (MDNode *OMD = dyn_cast_or_null<MDNode>(Op))
60 ToLook.push_back(OMD);
61
62 Visited.insert(MD);
63 }
64
65 for (auto &T : Tuples) {
66 auto [DbgNode, OpIdx, Tup] = T;
67 // Remove the operands of the tuple that are not in the desired chunks.
68 SmallVector<Metadata *, 16> TN;
69 for (size_t I = 0; I < Tup->getNumOperands(); ++I) {
70 // Ignore any operands that are not DebugInfo metadata nodes.
71 if (isa_and_nonnull<DINode>(Tup->getOperand(I)))
72 // Don't add uninteresting operands to the tuple.
73 if (!O.shouldKeep())
74 continue;
75
76 TN.push_back(Tup->getOperand(I));
77 }
78 if (TN.size() != Tup->getNumOperands())
79 DbgNode->replaceOperandWith(OpIdx, DbgNode->get(DbgNode->getContext(), TN));
80 }
81 }
82
extractDIMetadataFromModule(Oracle & O,ReducerWorkItem & WorkItem)83 static void extractDIMetadataFromModule(Oracle &O, ReducerWorkItem &WorkItem) {
84 Module &Program = WorkItem.getModule();
85
86 MDNodeList MDs;
87 // Collect all !dbg metadata attachments.
88 for (const auto &DC : Program.debug_compile_units())
89 if (DC)
90 MDs.push_back(DC);
91 for (GlobalVariable &GV : Program.globals())
92 GV.getMetadata(llvm::LLVMContext::MD_dbg, MDs);
93 for (Function &F : Program.functions()) {
94 F.getMetadata(llvm::LLVMContext::MD_dbg, MDs);
95 for (Instruction &I : instructions(F))
96 if (auto *DI = I.getMetadata(llvm::LLVMContext::MD_dbg))
97 MDs.push_back(DI);
98 }
99 identifyUninterestingMDNodes(O, MDs);
100 }
101
reduceDIMetadataDeltaPass(TestRunner & Test)102 void llvm::reduceDIMetadataDeltaPass(TestRunner &Test) {
103 runDeltaPass(Test, extractDIMetadataFromModule, "Reducing DIMetadata");
104 }
105