1 //===-- Instrumentation.cpp - TransformUtils Infrastructure ---------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file defines the common initialization infrastructure for the
11 // Instrumentation library.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "llvm/Transforms/Instrumentation.h"
16 #include "llvm-c/Initialization.h"
17 #include "llvm/ADT/Triple.h"
18 #include "llvm/IR/IntrinsicInst.h"
19 #include "llvm/IR/Module.h"
20 #include "llvm/InitializePasses.h"
21 #include "llvm/PassRegistry.h"
22 
23 using namespace llvm;
24 
25 /// Moves I before IP. Returns new insert point.
26 static BasicBlock::iterator moveBeforeInsertPoint(BasicBlock::iterator I, BasicBlock::iterator IP) {
27   // If I is IP, move the insert point down.
28   if (I == IP)
29     return ++IP;
30   // Otherwise, move I before IP and return IP.
31   I->moveBefore(&*IP);
32   return IP;
33 }
34 
35 /// Instrumentation passes often insert conditional checks into entry blocks.
36 /// Call this function before splitting the entry block to move instructions
37 /// that must remain in the entry block up before the split point. Static
38 /// allocas and llvm.localescape calls, for example, must remain in the entry
39 /// block.
40 BasicBlock::iterator llvm::PrepareToSplitEntryBlock(BasicBlock &BB,
41                                                     BasicBlock::iterator IP) {
42   assert(&BB.getParent()->getEntryBlock() == &BB);
43   for (auto I = IP, E = BB.end(); I != E; ++I) {
44     bool KeepInEntry = false;
45     if (auto *AI = dyn_cast<AllocaInst>(I)) {
46       if (AI->isStaticAlloca())
47         KeepInEntry = true;
48     } else if (auto *II = dyn_cast<IntrinsicInst>(I)) {
49       if (II->getIntrinsicID() == llvm::Intrinsic::localescape)
50         KeepInEntry = true;
51     }
52     if (KeepInEntry)
53       IP = moveBeforeInsertPoint(I, IP);
54   }
55   return IP;
56 }
57 
58 // Create a constant for Str so that we can pass it to the run-time lib.
59 GlobalVariable *llvm::createPrivateGlobalForString(Module &M, StringRef Str,
60                                                    bool AllowMerging,
61                                                    const char *NamePrefix) {
62   Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str);
63   // We use private linkage for module-local strings. If they can be merged
64   // with another one, we set the unnamed_addr attribute.
65   GlobalVariable *GV =
66       new GlobalVariable(M, StrConst->getType(), true,
67                          GlobalValue::PrivateLinkage, StrConst, NamePrefix);
68   if (AllowMerging)
69     GV->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
70   GV->setAlignment(1);  // Strings may not be merged w/o setting align 1.
71   return GV;
72 }
73 
74 Comdat *llvm::GetOrCreateFunctionComdat(Function &F, Triple &T,
75                                         const std::string &ModuleId) {
76   if (auto Comdat = F.getComdat()) return Comdat;
77   assert(F.hasName());
78   Module *M = F.getParent();
79   std::string Name = F.getName();
80 
81   // Make a unique comdat name for internal linkage things on ELF. On COFF, the
82   // name of the comdat group identifies the leader symbol of the comdat group.
83   // The linkage of the leader symbol is considered during comdat resolution,
84   // and internal symbols with the same name from different objects will not be
85   // merged.
86   if (T.isOSBinFormatELF() && F.hasLocalLinkage()) {
87     if (ModuleId.empty())
88       return nullptr;
89     Name += ModuleId;
90   }
91 
92   // Make a new comdat for the function. Use the "no duplicates" selection kind
93   // for non-weak symbols if the object file format supports it.
94   Comdat *C = M->getOrInsertComdat(Name);
95   if (T.isOSBinFormatCOFF() && !F.isWeakForLinker())
96     C->setSelectionKind(Comdat::NoDuplicates);
97   F.setComdat(C);
98   return C;
99 }
100 
101 /// initializeInstrumentation - Initialize all passes in the TransformUtils
102 /// library.
103 void llvm::initializeInstrumentation(PassRegistry &Registry) {
104   initializeAddressSanitizerPass(Registry);
105   initializeAddressSanitizerModulePass(Registry);
106   initializeBoundsCheckingLegacyPassPass(Registry);
107   initializeControlHeightReductionLegacyPassPass(Registry);
108   initializeGCOVProfilerLegacyPassPass(Registry);
109   initializePGOInstrumentationGenLegacyPassPass(Registry);
110   initializePGOInstrumentationUseLegacyPassPass(Registry);
111   initializePGOIndirectCallPromotionLegacyPassPass(Registry);
112   initializePGOMemOPSizeOptLegacyPassPass(Registry);
113   initializeInstrProfilingLegacyPassPass(Registry);
114   initializeMemorySanitizerLegacyPassPass(Registry);
115   initializeHWAddressSanitizerPass(Registry);
116   initializeThreadSanitizerLegacyPassPass(Registry);
117   initializeSanitizerCoverageModulePass(Registry);
118   initializeDataFlowSanitizerPass(Registry);
119   initializeEfficiencySanitizerPass(Registry);
120 }
121 
122 /// LLVMInitializeInstrumentation - C binding for
123 /// initializeInstrumentation.
124 void LLVMInitializeInstrumentation(LLVMPassRegistryRef R) {
125   initializeInstrumentation(*unwrap(R));
126 }
127