1 //===-- AnnotationRemarks.cpp - Generate remarks for annotated instrs. ----===//
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 // Generate remarks for instructions marked with !annotation.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "llvm/Transforms/Scalar/AnnotationRemarks.h"
14 #include "llvm/ADT/MapVector.h"
15 #include "llvm/Analysis/OptimizationRemarkEmitter.h"
16 #include "llvm/Analysis/TargetLibraryInfo.h"
17 #include "llvm/IR/Function.h"
18 #include "llvm/IR/InstIterator.h"
19 #include "llvm/InitializePasses.h"
20 #include "llvm/Pass.h"
21 #include "llvm/Transforms/Scalar.h"
22 #include "llvm/Transforms/Utils/MemoryOpRemark.h"
23 
24 using namespace llvm;
25 using namespace llvm::ore;
26 
27 #define DEBUG_TYPE "annotation-remarks"
28 #define REMARK_PASS DEBUG_TYPE
29 
30 static void tryEmitAutoInitRemark(ArrayRef<Instruction *> Instructions,
31                                   OptimizationRemarkEmitter &ORE,
32                                   const TargetLibraryInfo &TLI) {
33   // For every auto-init annotation generate a separate remark.
34   for (Instruction *I : Instructions) {
35     if (!AutoInitRemark::canHandle(I))
36       continue;
37 
38     Function &F = *I->getParent()->getParent();
39     const DataLayout &DL = F.getParent()->getDataLayout();
40     AutoInitRemark Remark(ORE, REMARK_PASS, DL, TLI);
41     Remark.visit(I);
42   }
43 }
44 
45 static void runImpl(Function &F, const TargetLibraryInfo &TLI) {
46   if (!OptimizationRemarkEmitter::allowExtraAnalysis(F, REMARK_PASS))
47     return;
48 
49   // Track all annotated instructions aggregated based on their debug location.
50   DenseMap<MDNode *, SmallVector<Instruction *, 4>> DebugLoc2Annotated;
51 
52   OptimizationRemarkEmitter ORE(&F);
53   // First, generate a summary of the annotated instructions.
54   MapVector<StringRef, unsigned> Mapping;
55   for (Instruction &I : instructions(F)) {
56     if (!I.hasMetadata(LLVMContext::MD_annotation))
57       continue;
58     auto Iter = DebugLoc2Annotated.insert({I.getDebugLoc().getAsMDNode(), {}});
59     Iter.first->second.push_back(&I);
60 
61     for (const MDOperand &Op :
62          I.getMetadata(LLVMContext::MD_annotation)->operands()) {
63       auto Iter = Mapping.insert({cast<MDString>(Op.get())->getString(), 0});
64       Iter.first->second++;
65     }
66   }
67 
68   for (const auto &KV : Mapping)
69     ORE.emit(OptimizationRemarkAnalysis(REMARK_PASS, "AnnotationSummary",
70                                         F.getSubprogram(), &F.front())
71              << "Annotated " << NV("count", KV.second) << " instructions with "
72              << NV("type", KV.first));
73 
74   // For each debug location, look for all the instructions with annotations and
75   // generate more detailed remarks to be displayed at that location.
76   for (auto &KV : DebugLoc2Annotated) {
77     // Don't generate remarks with no debug location.
78     if (!KV.first)
79       continue;
80 
81     tryEmitAutoInitRemark(KV.second, ORE, TLI);
82   }
83 }
84 
85 namespace {
86 
87 struct AnnotationRemarksLegacy : public FunctionPass {
88   static char ID;
89 
90   AnnotationRemarksLegacy() : FunctionPass(ID) {
91     initializeAnnotationRemarksLegacyPass(*PassRegistry::getPassRegistry());
92   }
93 
94   bool runOnFunction(Function &F) override {
95     const TargetLibraryInfo &TLI =
96         getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F);
97     runImpl(F, TLI);
98     return false;
99   }
100 
101   void getAnalysisUsage(AnalysisUsage &AU) const override {
102     AU.setPreservesAll();
103     AU.addRequired<TargetLibraryInfoWrapperPass>();
104   }
105 };
106 
107 } // end anonymous namespace
108 
109 char AnnotationRemarksLegacy::ID = 0;
110 
111 INITIALIZE_PASS_BEGIN(AnnotationRemarksLegacy, "annotation-remarks",
112                       "Annotation Remarks", false, false)
113 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
114 INITIALIZE_PASS_END(AnnotationRemarksLegacy, "annotation-remarks",
115                     "Annotation Remarks", false, false)
116 
117 FunctionPass *llvm::createAnnotationRemarksLegacyPass() {
118   return new AnnotationRemarksLegacy();
119 }
120 
121 PreservedAnalyses AnnotationRemarksPass::run(Function &F,
122                                              FunctionAnalysisManager &AM) {
123   auto &TLI = AM.getResult<TargetLibraryAnalysis>(F);
124   runImpl(F, TLI);
125   return PreservedAnalyses::all();
126 }
127