From 866ee2353f7d0224644799d0d1faed53c7f3a06d Mon Sep 17 00:00:00 2001 From: Marco Elver Date: Fri, 29 May 2020 12:52:27 +0200 Subject: [KernelAddressSanitizer] Make globals constructors compatible with kernel Summary: This makes -fsanitize=kernel-address emit the correct globals constructors for the kernel. We had to do the following: - Disable generation of constructors that rely on linker features such as dead-global elimination. - Only emit constructors for globals *not* in explicit sections. The kernel uses sections for special globals, which we should not touch. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203493 Tested: 1. With 'clang/test/CodeGen/asan-globals.cpp'. 2. With test_kasan.ko, we can see: BUG: KASAN: global-out-of-bounds in kasan_global_oob+0xb3/0xba [test_kasan] Reviewers: glider, andreyknvl Reviewed By: glider Subscribers: cfe-commits, nickdesaulniers, hiraditya, llvm-commits Tags: #llvm, #clang Differential Revision: https://reviews.llvm.org/D80805 --- llvm/lib/Transforms/Utils/ModuleUtils.cpp | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) (limited to 'llvm/lib/Transforms/Utils/ModuleUtils.cpp') diff --git a/llvm/lib/Transforms/Utils/ModuleUtils.cpp b/llvm/lib/Transforms/Utils/ModuleUtils.cpp index b2e6d98..ef9f18a 100644 --- a/llvm/lib/Transforms/Utils/ModuleUtils.cpp +++ b/llvm/lib/Transforms/Utils/ModuleUtils.cpp @@ -119,6 +119,15 @@ llvm::declareSanitizerInitFunction(Module &M, StringRef InitName, AttributeList()); } +Function *llvm::createSanitizerCtor(Module &M, StringRef CtorName) { + Function *Ctor = Function::Create( + FunctionType::get(Type::getVoidTy(M.getContext()), false), + GlobalValue::InternalLinkage, CtorName, &M); + BasicBlock *CtorBB = BasicBlock::Create(M.getContext(), "", Ctor); + ReturnInst::Create(M.getContext(), CtorBB); + return Ctor; +} + std::pair llvm::createSanitizerCtorAndInitFunctions( Module &M, StringRef CtorName, StringRef InitName, ArrayRef InitArgTypes, ArrayRef InitArgs, @@ -128,11 +137,8 @@ std::pair llvm::createSanitizerCtorAndInitFunctions( "Sanitizer's init function expects different number of arguments"); FunctionCallee InitFunction = declareSanitizerInitFunction(M, InitName, InitArgTypes); - Function *Ctor = Function::Create( - FunctionType::get(Type::getVoidTy(M.getContext()), false), - GlobalValue::InternalLinkage, CtorName, &M); - BasicBlock *CtorBB = BasicBlock::Create(M.getContext(), "", Ctor); - IRBuilder<> IRB(ReturnInst::Create(M.getContext(), CtorBB)); + Function *Ctor = createSanitizerCtor(M, CtorName); + IRBuilder<> IRB(Ctor->getEntryBlock().getTerminator()); IRB.CreateCall(InitFunction, InitArgs); if (!VersionCheckName.empty()) { FunctionCallee VersionCheckFunction = M.getOrInsertFunction( -- cgit v1.1