llvm/tools/llvm-reduce/deltas/ReduceMetadata.cpp

   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
  24 static bool shouldKeepDebugIntrinsicMetadata(Instruction &I, MDNode &MD) {
  25   return isa<DILocation>(MD) && isa<DbgInfoIntrinsic>(I);
  26 }
  27
  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.
  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.
  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
 118 void llvm::reduceMetadataDeltaPass(TestRunner &Test) {
 119   runDeltaPass(Test, extractMetadataFromModule, "Reducing Metadata");
 120 }
 121
 122 void llvm::reduceNamedMetadataDeltaPass(TestRunner &Test) {
 123   runDeltaPass(Test, reduceNamedMetadataOperands, "Reducing Named Metadata");
 124 }