[compiler-rt] Avoid instrumenting sanitizer functions

Summary:
Function __asan_default_options is called by __asan_init before the
shadow memory got initialized. Instrumenting that function may lead
to flaky execution.

As the __asan_default_options is provided by users, we cannot expect
them to add the appropriate function atttributes to avoid
instrumentation.

Reviewers: kcc, rnk

Subscribers: dberris, chrisha, llvm-commits

Differential Revision: https://reviews.llvm.org/D24566

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@281503 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Etienne Bergeron 2016-09-14 17:18:37 +00:00
parent c348bc4aeb
commit 24624732a0
2 changed files with 34 additions and 6 deletions

View File

@ -1882,17 +1882,21 @@ void AddressSanitizer::markEscapedLocalAllocas(Function &F) {
bool AddressSanitizer::runOnFunction(Function &F) {
if (&F == AsanCtorFunction) return false;
if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage) return false;
DEBUG(dbgs() << "ASAN instrumenting:\n" << F << "\n");
initializeCallbacks(*F.getParent());
DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
if (!ClDebugFunc.empty() && ClDebugFunc == F.getName()) return false;
if (F.getName().find("__asan_") != std::string::npos) return false;
// If needed, insert __asan_init before checking for SanitizeAddress attr.
// This function needs to be called even if the function body is not
// instrumented.
maybeInsertAsanInitAtFunctionEntry(F);
// Leave if the function doesn't need instrumentation.
if (!F.hasFnAttribute(Attribute::SanitizeAddress)) return false;
if (!ClDebugFunc.empty() && ClDebugFunc != F.getName()) return false;
DEBUG(dbgs() << "ASAN instrumenting:\n" << F << "\n");
initializeCallbacks(*F.getParent());
DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
FunctionStateRAII CleanupObj(this);

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@ -0,0 +1,24 @@
; This test checks that we are not instrumenting sanitizer code.
; RUN: opt < %s -asan -asan-module -S | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
; Function Attrs: nounwind uwtable
define void @__asan_default_options(i32* %a) sanitize_address {
entry:
%tmp1 = load i32, i32* %a, align 4
%tmp2 = add i32 %tmp1, 1
store i32 %tmp2, i32* %a, align 4
ret void
}
; CHECK-NOT: call void @__asan_report_load
; Function Attrs: nounwind uwtable
define i32 @main() #0 {
entry:
ret i32 0
}
; CHECK: declare void @__asan_init()