| File: | src/gnu/usr.bin/clang/libLLVM/../../../llvm/llvm/lib/CodeGen/ReturnProtectorPass.cpp |
| Warning: | line 42, column 9 Called C++ object pointer is null |
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| 1 | //===- ReturnProtectorPass.cpp - Set up rteurn protectors -----------------===// | |||
| 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 pass sets up functions for return protectors. | |||
| 11 | // | |||
| 12 | //===----------------------------------------------------------------------===// | |||
| 13 | ||||
| 14 | #include "llvm/CodeGen/Passes.h" | |||
| 15 | #include "llvm/ADT/Statistic.h" | |||
| 16 | #include "llvm/IR/Function.h" | |||
| 17 | #include "llvm/IR/Module.h" | |||
| 18 | #include "llvm/InitializePasses.h" | |||
| 19 | #include "llvm/Pass.h" | |||
| 20 | #include "llvm/Support/raw_ostream.h" | |||
| 21 | using namespace llvm; | |||
| 22 | ||||
| 23 | #define DEBUG_TYPE"return-protector" "return-protector" | |||
| 24 | ||||
| 25 | STATISTIC(NumSymbols, "Counts number of cookie symbols added")static llvm::Statistic NumSymbols = {"return-protector", "NumSymbols" , "Counts number of cookie symbols added"}; | |||
| 26 | ||||
| 27 | namespace { | |||
| 28 | struct ReturnProtector : public FunctionPass { | |||
| 29 | static char ID; | |||
| 30 | ReturnProtector() : FunctionPass(ID) {} | |||
| 31 | ||||
| 32 | bool runOnFunction(Function &F) override { | |||
| 33 | if (F.hasFnAttribute("ret-protector")) { | |||
| ||||
| 34 | // Create a symbol for the cookie | |||
| 35 | Module *M = F.getParent(); | |||
| 36 | std::hash<std::string> hasher; | |||
| 37 | std::string hash = std::to_string(hasher((M->getName() + F.getName()).str()) % 4000); | |||
| 38 | std::string cookiename = "__retguard_" + hash; | |||
| 39 | Type *cookietype = Type::getInt8PtrTy(M->getContext()); | |||
| 40 | GlobalVariable *cookie = dyn_cast_or_null<GlobalVariable>( | |||
| 41 | M->getOrInsertGlobal(cookiename, cookietype)); | |||
| 42 | cookie->setInitializer(Constant::getNullValue(cookietype)); | |||
| ||||
| 43 | cookie->setLinkage(GlobalVariable::LinkOnceAnyLinkage); | |||
| 44 | cookie->setVisibility(GlobalValue::HiddenVisibility); | |||
| 45 | cookie->setComdat(M->getOrInsertComdat(cookiename)); | |||
| 46 | cookie->setSection(".openbsd.randomdata.retguard." + hash); | |||
| 47 | cookie->setExternallyInitialized(true); | |||
| 48 | F.addFnAttr("ret-protector-cookie", cookiename); | |||
| 49 | NumSymbols++; | |||
| 50 | } | |||
| 51 | return false; | |||
| 52 | } | |||
| 53 | ||||
| 54 | void getAnalysisUsage(AnalysisUsage &AU) const override { | |||
| 55 | AU.setPreservesCFG(); | |||
| 56 | } | |||
| 57 | }; | |||
| 58 | } | |||
| 59 | ||||
| 60 | char ReturnProtector::ID = 0; | |||
| 61 | INITIALIZE_PASS(ReturnProtector, "return-protector", "Return Protector Pass",static void *initializeReturnProtectorPassOnce(PassRegistry & Registry) { PassInfo *PI = new PassInfo( "Return Protector Pass" , "return-protector", &ReturnProtector::ID, PassInfo::NormalCtor_t (callDefaultCtor<ReturnProtector>), false, false); Registry .registerPass(*PI, true); return PI; } static llvm::once_flag InitializeReturnProtectorPassFlag; void llvm::initializeReturnProtectorPass (PassRegistry &Registry) { llvm::call_once(InitializeReturnProtectorPassFlag , initializeReturnProtectorPassOnce, std::ref(Registry)); } | |||
| 62 | false, false)static void *initializeReturnProtectorPassOnce(PassRegistry & Registry) { PassInfo *PI = new PassInfo( "Return Protector Pass" , "return-protector", &ReturnProtector::ID, PassInfo::NormalCtor_t (callDefaultCtor<ReturnProtector>), false, false); Registry .registerPass(*PI, true); return PI; } static llvm::once_flag InitializeReturnProtectorPassFlag; void llvm::initializeReturnProtectorPass (PassRegistry &Registry) { llvm::call_once(InitializeReturnProtectorPassFlag , initializeReturnProtectorPassOnce, std::ref(Registry)); } | |||
| 63 | FunctionPass *llvm::createReturnProtectorPass() { return new ReturnProtector(); } |