[llvm] [HWASan] fix missing BTI attribute on personality function thunks (PR #139138)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: Florian Mayer (fmayer)

<details>
<summary>Changes</summary>

This used to work because the BTI attribute was taken from the module in
the CodeGen.

e15d67cfc2e5775cc79281aa860f3ad3be628f39 changed that to actually look
at the function attributes. This led to crashes for BTI, because we did
not emit the proper landing pads for the thunk.


---
Full diff: https://github.com/llvm/llvm-project/pull/139138.diff


2 Files Affected:

- (modified) llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp (+6) 
- (added) llvm/test/Instrumentation/HWAddressSanitizer/personality-bti.ll (+95) 


``````````diff
diff --git a/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
index 61dfc6411fc3a..2f7712171bab2 100644
--- a/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/HWAddressSanitizer.cpp
@@ -1847,6 +1847,12 @@ void HWAddressSanitizer::instrumentPersonalityFunctions() {
                                      IsLocal ? GlobalValue::InternalLinkage
                                              : GlobalValue::LinkOnceODRLinkage,
                                      ThunkName, &M);
+    // TODO: think about other attributes as well.
+    if (any_of(P.second, [](const Function *F) {
+          return F->hasFnAttribute("branch-target-enforcement");
+        })) {
+      ThunkFn->addFnAttr("branch-target-enforcement");
+    }
     if (!IsLocal) {
       ThunkFn->setVisibility(GlobalValue::HiddenVisibility);
       ThunkFn->setComdat(M.getOrInsertComdat(ThunkName));
diff --git a/llvm/test/Instrumentation/HWAddressSanitizer/personality-bti.ll b/llvm/test/Instrumentation/HWAddressSanitizer/personality-bti.ll
new file mode 100644
index 0000000000000..bdbbbdb90439c
--- /dev/null
+++ b/llvm/test/Instrumentation/HWAddressSanitizer/personality-bti.ll
@@ -0,0 +1,95 @@
+; RUN: opt < %s -mtriple aarch64-linux-android29 -passes=hwasan -S | FileCheck %s --check-prefix=NOPERS
+; RUN: opt < %s -mtriple aarch64-linux-android30 -passes=hwasan -S | FileCheck %s --check-prefix=PERS
+
+; NOPERS: define void @nostack() #{{[0-9]+}} {
+; PERS: define void @nostack() #{{[0-9]+}} {
+define void @nostack() sanitize_hwaddress "branch-target-enforcement" {
+  ret void
+}
+
+; NOPERS: define void @stack1() #{{[0-9]+}} {
+; PERS: personality {{.*}} @__hwasan_personality_thunk
+define void @stack1() sanitize_hwaddress "branch-target-enforcement" {
+  %p = alloca i8
+  call void @sink(ptr %p)
+  ret void
+}
+
+
+; NOPERS: personality ptr @global
+; PERS: personality {{.*}} @__hwasan_personality_thunk.global
+define void @stack2() sanitize_hwaddress "branch-target-enforcement" personality ptr @global {
+  %p = alloca i8
+  call void @sink(ptr %p)
+  ret void
+}
+
+define internal void @local() {
+  ret void
+}
+
+ at local_alias = internal alias void (), ptr @local
+
+; NOPERS: personality ptr @local
+; PERS: personality {{.*}} @__hwasan_personality_thunk.local
+define void @stack3() sanitize_hwaddress "branch-target-enforcement" personality ptr @local {
+  %p = alloca i8
+  call void @sink(ptr %p)
+  ret void
+}
+
+; NOPERS: personality ptr @local_alias
+; PERS: personality {{.*}} @__hwasan_personality_thunk.local_alias
+define void @stack4() sanitize_hwaddress "branch-target-enforcement" personality ptr @local_alias {
+  %p = alloca i8
+  call void @sink(ptr %p)
+  ret void
+}
+
+; NOPERS: personality ptr inttoptr (i64 1 to ptr)
+; PERS: personality ptr @__hwasan_personality_thunk.
+define void @stack5() sanitize_hwaddress "branch-target-enforcement" personality ptr inttoptr (i64 1 to ptr) {
+  %p = alloca i8
+  call void @sink(ptr %p)
+  ret void
+}
+
+; NOPERS: personality ptr inttoptr (i64 2 to ptr)
+; PERS: personality ptr @__hwasan_personality_thunk..1
+define void @stack6() sanitize_hwaddress "branch-target-enforcement" personality ptr inttoptr (i64 2 to ptr) {
+  %p = alloca i8
+  call void @sink(ptr %p)
+  ret void
+}
+
+declare void @global()
+declare void @sink(ptr)
+
+!llvm.module.flags = !{!0}
+!0 = !{i32 8, !"branch-target-enforcement", i32 1}
+
+; PERS: define linkonce_odr hidden i32 @__hwasan_personality_thunk(i32 %0, i32 %1, i64 %2, ptr %3, ptr %4) [[ATTRS:#[0-9]+]] comdat
+; PERS: %5 = tail call i32 @__hwasan_personality_wrapper(i32 %0, i32 %1, i64 %2, ptr %3, ptr %4, ptr null, ptr @_Unwind_GetGR, ptr @_Unwind_GetCFA)
+; PERS: ret i32 %5
+
+; PERS: define linkonce_odr hidden i32 @__hwasan_personality_thunk.global(i32 %0, i32 %1, i64 %2, ptr %3, ptr %4) {{.*}}[[ATTRS]] comdat
+; PERS: %5 = tail call i32 @__hwasan_personality_wrapper(i32 %0, i32 %1, i64 %2, ptr %3, ptr %4, ptr @global, ptr @_Unwind_GetGR, ptr @_Unwind_GetCFA)
+; PERS: ret i32 %5
+
+; PERS: define internal i32 @__hwasan_personality_thunk.local(i32 %0, i32 %1, i64 %2, ptr %3, ptr %4) {{.*}}[[ATTRS]]
+; PERS: %5 = tail call i32 @__hwasan_personality_wrapper(i32 %0, i32 %1, i64 %2, ptr %3, ptr %4, ptr @local, ptr @_Unwind_GetGR, ptr @_Unwind_GetCFA)
+; PERS: ret i32 %5
+
+; PERS: define internal i32 @__hwasan_personality_thunk.local_alias(i32 %0, i32 %1, i64 %2, ptr %3, ptr %4) {{.*}}[[ATTRS]]
+; PERS: %5 = tail call i32 @__hwasan_personality_wrapper(i32 %0, i32 %1, i64 %2, ptr %3, ptr %4, ptr @local_alias, ptr @_Unwind_GetGR, ptr @_Unwind_GetCFA)
+; PERS: ret i32 %5
+
+; PERS: define internal i32 @__hwasan_personality_thunk.(i32 %0, i32 %1, i64 %2, ptr %3, ptr %4) {{.*}}[[ATTRS]] {
+; PERS: %5 = tail call i32 @__hwasan_personality_wrapper(i32 %0, i32 %1, i64 %2, ptr %3, ptr %4, ptr inttoptr (i64 1 to ptr), ptr @_Unwind_GetGR, ptr @_Unwind_GetCFA)
+; PERS: ret i32 %5
+
+; PERS: define internal i32 @__hwasan_personality_thunk..1(i32 %0, i32 %1, i64 %2, ptr %3, ptr %4) {{.*}}[[ATTRS]] {
+; PERS: %5 = tail call i32 @__hwasan_personality_wrapper(i32 %0, i32 %1, i64 %2, ptr %3, ptr %4, ptr inttoptr (i64 2 to ptr), ptr @_Unwind_GetGR, ptr @_Unwind_GetCFA)
+; PERS: ret i32 %5
+
+; PERS: {{.*}}[[ATTRS]]
\ No newline at end of file

``````````

</details>


https://github.com/llvm/llvm-project/pull/139138