1//===-- CGProfile.cpp -----------------------------------------------------===//
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#include "llvm/Transforms/Instrumentation/CGProfile.h"
10
11#include "llvm/ADT/MapVector.h"
12#include "llvm/Analysis/BlockFrequencyInfo.h"
13#include "llvm/Analysis/LazyBlockFrequencyInfo.h"
14#include "llvm/Analysis/TargetTransformInfo.h"
15#include "llvm/IR/Constants.h"
16#include "llvm/IR/MDBuilder.h"
17#include "llvm/IR/PassManager.h"
18#include "llvm/ProfileData/InstrProf.h"
19#include "llvm/Transforms/Instrumentation.h"
20#include <optional>
21
22using namespace llvm;
23
24static bool
25addModuleFlags(Module &M,
26 MapVector<std::pair<Function *, Function *>, uint64_t> &Counts) {
27 if (Counts.empty())
28 return false;
29
30 LLVMContext &Context = M.getContext();
31 MDBuilder MDB(Context);
32 std::vector<Metadata *> Nodes;
33
34 for (auto E : Counts) {
35 Metadata *Vals[] = {ValueAsMetadata::get(V: E.first.first),
36 ValueAsMetadata::get(V: E.first.second),
37 MDB.createConstant(C: ConstantInt::get(
38 Ty: Type::getInt64Ty(C&: Context), V: E.second))};
39 Nodes.push_back(x: MDNode::get(Context, MDs: Vals));
40 }
41
42 M.addModuleFlag(Behavior: Module::Append, Key: "CG Profile",
43 Val: MDTuple::getDistinct(Context, MDs: Nodes));
44 return true;
45}
46
47static bool runCGProfilePass(Module &M, FunctionAnalysisManager &FAM,
48 bool InLTO) {
49 MapVector<std::pair<Function *, Function *>, uint64_t> Counts;
50 InstrProfSymtab Symtab;
51 auto UpdateCounts = [&](TargetTransformInfo &TTI, Function *F,
52 Function *CalledF, uint64_t NewCount) {
53 if (NewCount == 0)
54 return;
55 if (!CalledF || !TTI.isLoweredToCall(F: CalledF) ||
56 CalledF->hasDLLImportStorageClass())
57 return;
58 uint64_t &Count = Counts[std::make_pair(x&: F, y&: CalledF)];
59 Count = SaturatingAdd(X: Count, Y: NewCount);
60 };
61 // Ignore error here. Indirect calls are ignored if this fails.
62 (void)(bool)Symtab.create(M, InLTO);
63 for (auto &F : M) {
64 // Avoid extra cost of running passes for BFI when the function doesn't have
65 // entry count.
66 if (F.isDeclaration() || !F.getEntryCount())
67 continue;
68 auto &BFI = FAM.getResult<BlockFrequencyAnalysis>(IR&: F);
69 if (BFI.getEntryFreq() == BlockFrequency(0))
70 continue;
71 TargetTransformInfo &TTI = FAM.getResult<TargetIRAnalysis>(IR&: F);
72 for (auto &BB : F) {
73 std::optional<uint64_t> BBCount = BFI.getBlockProfileCount(BB: &BB);
74 if (!BBCount)
75 continue;
76 for (auto &I : BB) {
77 CallBase *CB = dyn_cast<CallBase>(Val: &I);
78 if (!CB)
79 continue;
80 if (CB->isIndirectCall()) {
81 InstrProfValueData ValueData[8];
82 uint32_t ActualNumValueData;
83 uint64_t TotalC;
84 if (!getValueProfDataFromInst(Inst: *CB, ValueKind: IPVK_IndirectCallTarget, MaxNumValueData: 8,
85 ValueData, ActualNumValueData, TotalC))
86 continue;
87 for (const auto &VD :
88 ArrayRef<InstrProfValueData>(ValueData, ActualNumValueData)) {
89 UpdateCounts(TTI, &F, Symtab.getFunction(FuncMD5Hash: VD.Value), VD.Count);
90 }
91 continue;
92 }
93 UpdateCounts(TTI, &F, CB->getCalledFunction(), *BBCount);
94 }
95 }
96 }
97
98 return addModuleFlags(M, Counts);
99}
100
101PreservedAnalyses CGProfilePass::run(Module &M, ModuleAnalysisManager &MAM) {
102 FunctionAnalysisManager &FAM =
103 MAM.getResult<FunctionAnalysisManagerModuleProxy>(IR&: M).getManager();
104 runCGProfilePass(M, FAM, InLTO);
105
106 return PreservedAnalyses::all();
107}
108

source code of llvm/lib/Transforms/Instrumentation/CGProfile.cpp