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