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/Transforms/Utils/MemoryOpRemark.h"
20 
21 using namespace llvm;
22 using namespace llvm::ore;
23 
24 #define DEBUG_TYPE "annotation-remarks"
25 #define REMARK_PASS DEBUG_TYPE
26 
27 static void tryEmitAutoInitRemark(ArrayRef<Instruction *> Instructions,
28                                   OptimizationRemarkEmitter &ORE,
29                                   const TargetLibraryInfo &TLI) {
30   // For every auto-init annotation generate a separate remark.
31   for (Instruction *I : Instructions) {
32     if (!AutoInitRemark::canHandle(I))
33       continue;
34 
35     Function &F = *I->getParent()->getParent();
36     const DataLayout &DL = F.getParent()->getDataLayout();
37     AutoInitRemark Remark(ORE, REMARK_PASS, DL, TLI);
38     Remark.visit(I);
39   }
40 }
41 
42 static void runImpl(Function &F, const TargetLibraryInfo &TLI) {
43   if (!OptimizationRemarkEmitter::allowExtraAnalysis(F, REMARK_PASS))
44     return;
45 
46   // Track all annotated instructions aggregated based on their debug location.
47   DenseMap<MDNode *, SmallVector<Instruction *, 4>> DebugLoc2Annotated;
48 
49   OptimizationRemarkEmitter ORE(&F);
50   // First, generate a summary of the annotated instructions.
51   MapVector<StringRef, unsigned> Mapping;
52   for (Instruction &I : instructions(F)) {
53     if (!I.hasMetadata(LLVMContext::MD_annotation))
54       continue;
55     auto Iter = DebugLoc2Annotated.insert({I.getDebugLoc().getAsMDNode(), {}});
56     Iter.first->second.push_back(&I);
57 
58     for (const MDOperand &Op :
59          I.getMetadata(LLVMContext::MD_annotation)->operands()) {
60       StringRef AnnotationStr =
61           isa<MDString>(Op.get())
62               ? cast<MDString>(Op.get())->getString()
63               : cast<MDString>(cast<MDTuple>(Op.get())->getOperand(0).get())
64                     ->getString();
65       auto Iter = Mapping.insert({AnnotationStr, 0});
66       Iter.first->second++;
67     }
68   }
69 
70   for (const auto &KV : Mapping)
71     ORE.emit(OptimizationRemarkAnalysis(REMARK_PASS, "AnnotationSummary",
72                                         F.getSubprogram(), &F.front())
73              << "Annotated " << NV("count", KV.second) << " instructions with "
74              << NV("type", KV.first));
75 
76   // For each debug location, look for all the instructions with annotations and
77   // generate more detailed remarks to be displayed at that location.
78   for (auto &KV : DebugLoc2Annotated) {
79     // Don't generate remarks with no debug location.
80     if (!KV.first)
81       continue;
82 
83     tryEmitAutoInitRemark(KV.second, ORE, TLI);
84   }
85 }
86 
87 PreservedAnalyses AnnotationRemarksPass::run(Function &F,
88                                              FunctionAnalysisManager &AM) {
89   auto &TLI = AM.getResult<TargetLibraryAnalysis>(F);
90   runImpl(F, TLI);
91   return PreservedAnalyses::all();
92 }
93