[ASan] Do not instrument other runtime functions with `__asan_handle_no_return`
Summary:
Currently, ASan inserts a call to `__asan_handle_no_return` before every
`noreturn` function call/invoke. This is unnecessary for calls to other
runtime funtions. This patch changes ASan to skip instrumentation for
functions calls marked with `!nosanitize` metadata.
Reviewers: TODO
Differential Revision: https://reviews.llvm.org/D57489
llvm-svn: 352948
diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 4051cfb..730dac3 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -4394,8 +4394,8 @@
// Strip away the noreturn attribute to better diagnose unreachable UB.
if (SanOpts.has(SanitizerKind::Unreachable)) {
- // Also remove from function since CI->hasFnAttr(..) also checks attributes
- // of the called function.
+ // Also remove from function since CallBase::hasFnAttr additionally checks
+ // attributes of the called function.
if (auto *F = CI->getCalledFunction())
F->removeFnAttr(llvm::Attribute::NoReturn);
CI->removeAttribute(llvm::AttributeList::FunctionIndex,
diff --git a/clang/test/CodeGen/ubsan-asan-noreturn.c b/clang/test/CodeGen/ubsan-asan-noreturn.c
index cd7b842..6dc0546 100644
--- a/clang/test/CodeGen/ubsan-asan-noreturn.c
+++ b/clang/test/CodeGen/ubsan-asan-noreturn.c
@@ -9,8 +9,7 @@
my_longjmp();
// CHECK: @__asan_handle_no_return{{.*}} !nosanitize
// CHECK-NEXT: @my_longjmp(){{[^#]*}}
- // CHECK: @__asan_handle_no_return()
- // CHECK-NEXT: @__ubsan_handle_builtin_unreachable{{.*}} !nosanitize
+ // CHECK: @__ubsan_handle_builtin_unreachable{{.*}} !nosanitize
// CHECK-NEXT: unreachable
}
diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
index 978ec49..e95b88b 100644
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -2554,7 +2554,8 @@
if (CS) {
// A call inside BB.
TempsToInstrument.clear();
- if (CS.doesNotReturn()) NoReturnCalls.push_back(CS.getInstruction());
+ if (CS.doesNotReturn() && !CS->getMetadata("nosanitize"))
+ NoReturnCalls.push_back(CS.getInstruction());
}
if (CallInst *CI = dyn_cast<CallInst>(&Inst))
maybeMarkSanitizerLibraryCallNoBuiltin(CI, TLI);
@@ -2591,7 +2592,7 @@
FunctionStackPoisoner FSP(F, *this);
bool ChangedStack = FSP.runOnFunction();
- // We must unpoison the stack before every NoReturn call (throw, _exit, etc).
+ // We must unpoison the stack before NoReturn calls (throw, _exit, etc).
// See e.g. https://github.com/google/sanitizers/issues/37
for (auto CI : NoReturnCalls) {
IRBuilder<> IRB(CI);
diff --git a/llvm/test/Instrumentation/AddressSanitizer/instrument-no-return.ll b/llvm/test/Instrumentation/AddressSanitizer/instrument-no-return.ll
index 2e90bfc..0df85c7 100644
--- a/llvm/test/Instrumentation/AddressSanitizer/instrument-no-return.ll
+++ b/llvm/test/Instrumentation/AddressSanitizer/instrument-no-return.ll
@@ -1,37 +1,45 @@
-; RUN: opt < %s -asan -asan-module -S | FileCheck %s
+; RUN: opt < %s -asan -S | FileCheck %s
; AddressSanitizer must insert __asan_handle_no_return
-; before every noreturn call or invoke.
+; before noreturn calls that aren't inserted by sanitizers.
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
target triple = "x86_64-unknown-linux-gnu"
-declare void @MyNoReturnFunc(i32) noreturn
+declare void @NormalFunc()
+declare void @NoReturnFunc() noreturn
-define i32 @Call1(i8* nocapture %arg) uwtable sanitize_address {
-entry:
- call void @MyNoReturnFunc(i32 1) noreturn ; The call insn has noreturn attr.
-; CHECK: @Call1
-; CHECK: call void @__asan_handle_no_return
-; CHECK-NEXT: call void @MyNoReturnFunc
-; CHECK-NEXT: unreachable
+; Instrument noreturn callsites (regardless of function)
+define i32 @Call1() sanitize_address {
+ call void @NormalFunc() noreturn
unreachable
}
+; CHECK-LABEL: @Call1
+; CHECK-NEXT: call void @__asan_handle_no_return
+; CHECK-NEXT: call void @NormalFunc
-define i32 @Call2(i8* nocapture %arg) uwtable sanitize_address {
-entry:
- call void @MyNoReturnFunc(i32 1) ; No noreturn attribure on the call.
-; CHECK: @Call2
-; CHECK: call void @__asan_handle_no_return
-; CHECK-NEXT: call void @MyNoReturnFunc
-; CHECK-NEXT: unreachable
+; Instrument calls to noreturn functions (regardless of callsite)
+define i32 @Call2() sanitize_address {
+ call void @NoReturnFunc()
unreachable
}
+; CHECK-LABEL: @Call2
+; CHECK-NEXT: call void @__asan_handle_no_return
+; CHECK-NEXT: call void @NoReturnFunc
+
+; Do *not* instrument callsites marked !nosanitize
+define i32 @Call3() sanitize_address {
+ call void @NoReturnFunc() noreturn, !nosanitize !{}
+ unreachable
+}
+; CHECK-LABEL: @Call3
+; CHECK-NOT: call void @__asan_handle_no_return
+; CHECK: call void @NoReturnFunc
declare i32 @__gxx_personality_v0(...)
-define i64 @Invoke1(i8** %esc) nounwind uwtable ssp sanitize_address personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
+define i64 @Invoke1() nounwind uwtable ssp sanitize_address personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
entry:
- invoke void @MyNoReturnFunc(i32 1)
+ invoke void @NoReturnFunc()
to label %invoke.cont unwind label %lpad
invoke.cont:
@@ -42,8 +50,8 @@
filter [0 x i8*] zeroinitializer
ret i64 1
}
-; CHECK: @Invoke1
+; CHECK-LABEL: @Invoke1
; CHECK: call void @__asan_handle_no_return
-; CHECK-NEXT: invoke void @MyNoReturnFunc
+; CHECK-NEXT: invoke void @NoReturnFunc
; CHECK: ret i64 0
; CHECK: ret i64 1