1//===- SanitizerStats.cpp - Sanitizer statistics gathering ----------------===//
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// Implements code generation for sanitizer statistics gathering.
10//
11//===----------------------------------------------------------------------===//
12
13#include "llvm/Transforms/Utils/SanitizerStats.h"
14#include "llvm/IR/Constants.h"
15#include "llvm/IR/DerivedTypes.h"
16#include "llvm/IR/GlobalVariable.h"
17#include "llvm/IR/IRBuilder.h"
18#include "llvm/IR/Module.h"
19#include "llvm/Transforms/Utils/ModuleUtils.h"
20
21using namespace llvm;
22
23SanitizerStatReport::SanitizerStatReport(Module *M) : M(M) {
24 StatTy = ArrayType::get(ElementType: PointerType::getUnqual(C&: M->getContext()), NumElements: 2);
25 EmptyModuleStatsTy = makeModuleStatsTy();
26
27 ModuleStatsGV = new GlobalVariable(*M, EmptyModuleStatsTy, false,
28 GlobalValue::InternalLinkage, nullptr);
29}
30
31ArrayType *SanitizerStatReport::makeModuleStatsArrayTy() {
32 return ArrayType::get(ElementType: StatTy, NumElements: Inits.size());
33}
34
35StructType *SanitizerStatReport::makeModuleStatsTy() {
36 return StructType::get(Context&: M->getContext(),
37 Elements: {PointerType::getUnqual(C&: M->getContext()),
38 Type::getInt32Ty(C&: M->getContext()),
39 makeModuleStatsArrayTy()});
40}
41
42void SanitizerStatReport::create(IRBuilder<> &B, SanitizerStatKind SK) {
43 Function *F = B.GetInsertBlock()->getParent();
44 Module *M = F->getParent();
45 PointerType *PtrTy = B.getPtrTy();
46 IntegerType *IntPtrTy = B.getIntPtrTy(DL: M->getDataLayout());
47 ArrayType *StatTy = ArrayType::get(ElementType: PtrTy, NumElements: 2);
48
49 Inits.push_back(x: ConstantArray::get(
50 T: StatTy,
51 V: {Constant::getNullValue(Ty: PtrTy),
52 ConstantExpr::getIntToPtr(
53 C: ConstantInt::get(Ty: IntPtrTy, V: uint64_t(SK) << (IntPtrTy->getBitWidth() -
54 kSanitizerStatKindBits)),
55 Ty: PtrTy)}));
56
57 FunctionType *StatReportTy = FunctionType::get(Result: B.getVoidTy(), Params: PtrTy, isVarArg: false);
58 FunctionCallee StatReport =
59 M->getOrInsertFunction(Name: "__sanitizer_stat_report", T: StatReportTy);
60
61 auto InitAddr = ConstantExpr::getGetElementPtr(
62 Ty: EmptyModuleStatsTy, C: ModuleStatsGV,
63 IdxList: ArrayRef<Constant *>{
64 ConstantInt::get(Ty: IntPtrTy, V: 0), ConstantInt::get(Ty: B.getInt32Ty(), V: 2),
65 ConstantInt::get(Ty: IntPtrTy, V: Inits.size() - 1),
66 });
67 B.CreateCall(Callee: StatReport, Args: InitAddr);
68}
69
70void SanitizerStatReport::finish() {
71 if (Inits.empty()) {
72 ModuleStatsGV->eraseFromParent();
73 return;
74 }
75
76 PointerType *Int8PtrTy = PointerType::getUnqual(C&: M->getContext());
77 IntegerType *Int32Ty = Type::getInt32Ty(C&: M->getContext());
78 Type *VoidTy = Type::getVoidTy(C&: M->getContext());
79
80 // Create a new ModuleStatsGV to replace the old one. We can't just set the
81 // old one's initializer because its type is different.
82 auto NewModuleStatsGV = new GlobalVariable(
83 *M, makeModuleStatsTy(), false, GlobalValue::InternalLinkage,
84 ConstantStruct::getAnon(
85 V: {Constant::getNullValue(Ty: Int8PtrTy),
86 ConstantInt::get(Ty: Int32Ty, V: Inits.size()),
87 ConstantArray::get(T: makeModuleStatsArrayTy(), V: Inits)}));
88 ModuleStatsGV->replaceAllUsesWith(V: NewModuleStatsGV);
89 ModuleStatsGV->eraseFromParent();
90
91 // Create a global constructor to register NewModuleStatsGV.
92 auto F = Function::Create(Ty: FunctionType::get(Result: VoidTy, isVarArg: false),
93 Linkage: GlobalValue::InternalLinkage, N: "", M);
94 auto BB = BasicBlock::Create(Context&: M->getContext(), Name: "", Parent: F);
95 IRBuilder<> B(BB);
96
97 FunctionType *StatInitTy = FunctionType::get(Result: VoidTy, Params: Int8PtrTy, isVarArg: false);
98 FunctionCallee StatInit =
99 M->getOrInsertFunction(Name: "__sanitizer_stat_init", T: StatInitTy);
100
101 B.CreateCall(Callee: StatInit, Args: NewModuleStatsGV);
102 B.CreateRetVoid();
103
104 appendToGlobalCtors(M&: *M, F, Priority: 0);
105}
106

source code of llvm/lib/Transforms/Utils/SanitizerStats.cpp