1 //===-- Instrumentation.cpp - TransformUtils Infrastructure ---------------===// 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 // This file defines the common initialization infrastructure for the 10 // Instrumentation library. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/Transforms/Instrumentation.h" 15 #include "llvm-c/Initialization.h" 16 #include "llvm/ADT/Triple.h" 17 #include "llvm/IR/IntrinsicInst.h" 18 #include "llvm/IR/Module.h" 19 #include "llvm/InitializePasses.h" 20 #include "llvm/PassRegistry.h" 21 22 using namespace llvm; 23 24 /// Moves I before IP. Returns new insert point. 25 static BasicBlock::iterator moveBeforeInsertPoint(BasicBlock::iterator I, BasicBlock::iterator IP) { 26 // If I is IP, move the insert point down. 27 if (I == IP) { 28 ++IP; 29 } else { 30 // Otherwise, move I before IP and return IP. 31 I->moveBefore(&*IP); 32 } 33 return IP; 34 } 35 36 /// Instrumentation passes often insert conditional checks into entry blocks. 37 /// Call this function before splitting the entry block to move instructions 38 /// that must remain in the entry block up before the split point. Static 39 /// allocas and llvm.localescape calls, for example, must remain in the entry 40 /// block. 41 BasicBlock::iterator llvm::PrepareToSplitEntryBlock(BasicBlock &BB, 42 BasicBlock::iterator IP) { 43 assert(&BB.getParent()->getEntryBlock() == &BB); 44 for (auto I = IP, E = BB.end(); I != E; ++I) { 45 bool KeepInEntry = false; 46 if (auto *AI = dyn_cast<AllocaInst>(I)) { 47 if (AI->isStaticAlloca()) 48 KeepInEntry = true; 49 } else if (auto *II = dyn_cast<IntrinsicInst>(I)) { 50 if (II->getIntrinsicID() == llvm::Intrinsic::localescape) 51 KeepInEntry = true; 52 } 53 if (KeepInEntry) 54 IP = moveBeforeInsertPoint(I, IP); 55 } 56 return IP; 57 } 58 59 // Create a constant for Str so that we can pass it to the run-time lib. 60 GlobalVariable *llvm::createPrivateGlobalForString(Module &M, StringRef Str, 61 bool AllowMerging, 62 const char *NamePrefix) { 63 Constant *StrConst = ConstantDataArray::getString(M.getContext(), Str); 64 // We use private linkage for module-local strings. If they can be merged 65 // with another one, we set the unnamed_addr attribute. 66 GlobalVariable *GV = 67 new GlobalVariable(M, StrConst->getType(), true, 68 GlobalValue::PrivateLinkage, StrConst, NamePrefix); 69 if (AllowMerging) 70 GV->setUnnamedAddr(GlobalValue::UnnamedAddr::Global); 71 GV->setAlignment(Align(1)); // Strings may not be merged w/o setting 72 // alignment explicitly. 73 return GV; 74 } 75 76 Comdat *llvm::getOrCreateFunctionComdat(Function &F, Triple &T) { 77 if (auto Comdat = F.getComdat()) return Comdat; 78 assert(F.hasName()); 79 Module *M = F.getParent(); 80 81 // Make a new comdat for the function. Use the "no duplicates" selection kind 82 // if the object file format supports it. For COFF we restrict it to non-weak 83 // symbols. 84 Comdat *C = M->getOrInsertComdat(F.getName()); 85 if (T.isOSBinFormatELF() || (T.isOSBinFormatCOFF() && !F.isWeakForLinker())) 86 C->setSelectionKind(Comdat::NoDeduplicate); 87 F.setComdat(C); 88 return C; 89 } 90 91 /// initializeInstrumentation - Initialize all passes in the TransformUtils 92 /// library. 93 void llvm::initializeInstrumentation(PassRegistry &Registry) { 94 initializeMemProfilerLegacyPassPass(Registry); 95 initializeModuleMemProfilerLegacyPassPass(Registry); 96 initializeBoundsCheckingLegacyPassPass(Registry); 97 initializeDataFlowSanitizerLegacyPassPass(Registry); 98 } 99 100 /// LLVMInitializeInstrumentation - C binding for 101 /// initializeInstrumentation. 102 void LLVMInitializeInstrumentation(LLVMPassRegistryRef R) { 103 initializeInstrumentation(*unwrap(R)); 104 } 105