1 //===- ReduceMetadata.cpp - Specialized Delta Pass ------------------------===//
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 Metadata nodes.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "ReduceMetadata.h"
15 #include "Delta.h"
16 #include "llvm/ADT/Sequence.h"
17 #include "llvm/ADT/SmallVector.h"
18 #include "llvm/IR/InstIterator.h"
19 #include "llvm/IR/IntrinsicInst.h"
20 #include <vector>
21
22 using namespace llvm;
23
shouldKeepDebugIntrinsicMetadata(Instruction & I,MDNode & MD)24 static bool shouldKeepDebugIntrinsicMetadata(Instruction &I, MDNode &MD) {
25 return isa<DILocation>(MD) && isa<DbgInfoIntrinsic>(I);
26 }
27
shouldKeepDebugNamedMetadata(NamedMDNode & MD)28 static bool shouldKeepDebugNamedMetadata(NamedMDNode &MD) {
29 return MD.getName() == "llvm.dbg.cu" && MD.getNumOperands() != 0;
30 }
31
32 // Named metadata with simple list-like behavior, so that it's valid to remove
33 // operands individually.
34 static constexpr StringLiteral ListNamedMetadata[] = {
35 "llvm.module.flags",
36 "llvm.ident",
37 "opencl.spir.version",
38 "opencl.ocl.version",
39 "opencl.used.extensions",
40 "opencl.used.optional.core.features",
41 "opencl.compiler.options"
42 };
43
44 /// Remove unneeded arguments to named metadata.
reduceNamedMetadataOperands(Oracle & O,ReducerWorkItem & WorkItem)45 static void reduceNamedMetadataOperands(Oracle &O, ReducerWorkItem &WorkItem) {
46 Module &M = WorkItem.getModule();
47
48 for (StringRef MDName : ListNamedMetadata) {
49 NamedMDNode *NamedNode = M.getNamedMetadata(MDName);
50 if (!NamedNode)
51 continue;
52
53 bool MadeChange = false;
54 SmallVector<MDNode *, 16> KeptOperands;
55 for (auto I : seq<unsigned>(0, NamedNode->getNumOperands())) {
56 if (O.shouldKeep())
57 KeptOperands.push_back(NamedNode->getOperand(I));
58 else
59 MadeChange = true;
60 }
61
62 if (MadeChange) {
63 NamedNode->clearOperands();
64 for (MDNode *KeptOperand : KeptOperands)
65 NamedNode->addOperand(KeptOperand);
66 }
67 }
68 }
69
70 /// Removes all the Named and Unnamed Metadata Nodes, as well as any debug
71 /// functions that aren't inside the desired Chunks.
extractMetadataFromModule(Oracle & O,ReducerWorkItem & WorkItem)72 static void extractMetadataFromModule(Oracle &O, ReducerWorkItem &WorkItem) {
73 Module &Program = WorkItem.getModule();
74
75 // Get out-of-chunk Named metadata nodes
76 SmallVector<NamedMDNode *> NamedNodesToDelete;
77 for (NamedMDNode &MD : Program.named_metadata())
78 if (!shouldKeepDebugNamedMetadata(MD) && !O.shouldKeep())
79 NamedNodesToDelete.push_back(&MD);
80
81 for (NamedMDNode *NN : NamedNodesToDelete) {
82 for (auto I : seq<unsigned>(0, NN->getNumOperands()))
83 NN->setOperand(I, nullptr);
84 NN->eraseFromParent();
85 }
86
87 // Delete out-of-chunk metadata attached to globals.
88 for (GlobalVariable &GV : Program.globals()) {
89 SmallVector<std::pair<unsigned, MDNode *>> MDs;
90 GV.getAllMetadata(MDs);
91 for (std::pair<unsigned, MDNode *> &MD : MDs)
92 if (!O.shouldKeep())
93 GV.setMetadata(MD.first, nullptr);
94 }
95
96 for (Function &F : Program) {
97 {
98 SmallVector<std::pair<unsigned, MDNode *>> MDs;
99 // Delete out-of-chunk metadata attached to functions.
100 F.getAllMetadata(MDs);
101 for (std::pair<unsigned, MDNode *> &MD : MDs)
102 if (!O.shouldKeep())
103 F.setMetadata(MD.first, nullptr);
104 }
105
106 // Delete out-of-chunk metadata attached to instructions.
107 for (Instruction &I : instructions(F)) {
108 SmallVector<std::pair<unsigned, MDNode *>> MDs;
109 I.getAllMetadata(MDs);
110 for (std::pair<unsigned, MDNode *> &MD : MDs) {
111 if (!shouldKeepDebugIntrinsicMetadata(I, *MD.second) && !O.shouldKeep())
112 I.setMetadata(MD.first, nullptr);
113 }
114 }
115 }
116 }
117
reduceMetadataDeltaPass(TestRunner & Test)118 void llvm::reduceMetadataDeltaPass(TestRunner &Test) {
119 runDeltaPass(Test, extractMetadataFromModule, "Reducing Metadata");
120 }
121
reduceNamedMetadataDeltaPass(TestRunner & Test)122 void llvm::reduceNamedMetadataDeltaPass(TestRunner &Test) {
123 runDeltaPass(Test, reduceNamedMetadataOperands, "Reducing Named Metadata");
124 }
125