xref: /freebsd/contrib/llvm-project/llvm/lib/Transforms/Utils/SanitizerStats.cpp (revision cfd6422a5217410fbd66f7a7a8a64d9d85e61229)
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/ADT/Triple.h"
15 #include "llvm/IR/Constants.h"
16 #include "llvm/IR/DerivedTypes.h"
17 #include "llvm/IR/GlobalVariable.h"
18 #include "llvm/IR/IRBuilder.h"
19 #include "llvm/IR/Module.h"
20 #include "llvm/Transforms/Utils/ModuleUtils.h"
21 
22 using namespace llvm;
23 
24 SanitizerStatReport::SanitizerStatReport(Module *M) : M(M) {
25   StatTy = ArrayType::get(Type::getInt8PtrTy(M->getContext()), 2);
26   EmptyModuleStatsTy = makeModuleStatsTy();
27 
28   ModuleStatsGV = new GlobalVariable(*M, EmptyModuleStatsTy, false,
29                                      GlobalValue::InternalLinkage, nullptr);
30 }
31 
32 ArrayType *SanitizerStatReport::makeModuleStatsArrayTy() {
33   return ArrayType::get(StatTy, Inits.size());
34 }
35 
36 StructType *SanitizerStatReport::makeModuleStatsTy() {
37   return StructType::get(M->getContext(), {Type::getInt8PtrTy(M->getContext()),
38                                            Type::getInt32Ty(M->getContext()),
39                                            makeModuleStatsArrayTy()});
40 }
41 
42 void SanitizerStatReport::create(IRBuilder<> &B, SanitizerStatKind SK) {
43   Function *F = B.GetInsertBlock()->getParent();
44   Module *M = F->getParent();
45   PointerType *Int8PtrTy = B.getInt8PtrTy();
46   IntegerType *IntPtrTy = B.getIntPtrTy(M->getDataLayout());
47   ArrayType *StatTy = ArrayType::get(Int8PtrTy, 2);
48 
49   Inits.push_back(ConstantArray::get(
50       StatTy,
51       {Constant::getNullValue(Int8PtrTy),
52        ConstantExpr::getIntToPtr(
53            ConstantInt::get(IntPtrTy, uint64_t(SK) << (IntPtrTy->getBitWidth() -
54                                                        kSanitizerStatKindBits)),
55            Int8PtrTy)}));
56 
57   FunctionType *StatReportTy =
58       FunctionType::get(B.getVoidTy(), Int8PtrTy, false);
59   FunctionCallee StatReport =
60       M->getOrInsertFunction("__sanitizer_stat_report", StatReportTy);
61 
62   auto InitAddr = ConstantExpr::getGetElementPtr(
63       EmptyModuleStatsTy, ModuleStatsGV,
64       ArrayRef<Constant *>{
65           ConstantInt::get(IntPtrTy, 0), ConstantInt::get(B.getInt32Ty(), 2),
66           ConstantInt::get(IntPtrTy, Inits.size() - 1),
67       });
68   B.CreateCall(StatReport, ConstantExpr::getBitCast(InitAddr, Int8PtrTy));
69 }
70 
71 void SanitizerStatReport::finish() {
72   if (Inits.empty()) {
73     ModuleStatsGV->eraseFromParent();
74     return;
75   }
76 
77   PointerType *Int8PtrTy = Type::getInt8PtrTy(M->getContext());
78   IntegerType *Int32Ty = Type::getInt32Ty(M->getContext());
79   Type *VoidTy = Type::getVoidTy(M->getContext());
80 
81   // Create a new ModuleStatsGV to replace the old one. We can't just set the
82   // old one's initializer because its type is different.
83   auto NewModuleStatsGV = new GlobalVariable(
84       *M, makeModuleStatsTy(), false, GlobalValue::InternalLinkage,
85       ConstantStruct::getAnon(
86           {Constant::getNullValue(Int8PtrTy),
87            ConstantInt::get(Int32Ty, Inits.size()),
88            ConstantArray::get(makeModuleStatsArrayTy(), Inits)}));
89   ModuleStatsGV->replaceAllUsesWith(
90       ConstantExpr::getBitCast(NewModuleStatsGV, ModuleStatsGV->getType()));
91   ModuleStatsGV->eraseFromParent();
92 
93   // Create a global constructor to register NewModuleStatsGV.
94   auto F = Function::Create(FunctionType::get(VoidTy, false),
95                             GlobalValue::InternalLinkage, "", M);
96   auto BB = BasicBlock::Create(M->getContext(), "", F);
97   IRBuilder<> B(BB);
98 
99   FunctionType *StatInitTy = FunctionType::get(VoidTy, Int8PtrTy, false);
100   FunctionCallee StatInit =
101       M->getOrInsertFunction("__sanitizer_stat_init", StatInitTy);
102 
103   B.CreateCall(StatInit, ConstantExpr::getBitCast(NewModuleStatsGV, Int8PtrTy));
104   B.CreateRetVoid();
105 
106   appendToGlobalCtors(*M, F, 0);
107 }
108