https://github.com/delcypher created
https://github.com/llvm/llvm-project/pull/91032
Due to how `CodeGenFunction::EmitTrapCheck` is implemented `SanitizerHandler`
with numeric value 0x19 needs to be reserved because `-fbounds-safety`
generates trap instructions with that value embedded in the trap instructions
for x86_64 and arm64 just like for UBSan traps.
** x86_64 **
```
ud1l 0x19(%eax), %eax
```
** arm64 **
```
brk #0x5519
```
To avoid upstream Clang and AppleClang diverging their ABIs for
`-fbounds-safety` the slot is being reserved in this patch.
`SanitizerHandler::BoundsSafety` currently has no uses in the code but uses
will be introduced when the CodeGen side of `-fbounds-safety`'s implementation
is upstreamed.
rdar://126884014
>From 644a56944963bb6445b58fd2162b2781e3180ba9 Mon Sep 17 00:00:00 2001
From: Dan Liew <d...@su-root.co.uk>
Date: Fri, 3 May 2024 16:16:17 -0700
Subject: [PATCH] [Bounds-Safety] Reserve slot in SanitizerHandler enum for
Bounds-Safety
Due to how `CodeGenFunction::EmitTrapCheck` is implemented
`SanitizerHandler` with numeric value 0x19 needs to be reserved because
`-fbounds-safety` generates trap instructions with that value embedded
in the trap instructions for x86_64 and arm64 just like for UBSan
traps.
** x86_64 **
```
ud1l 0x19(%eax), %eax
```
** arm64 **
```
brk #0x5519
```
To avoid upstream Clang and AppleClang diverging their ABIs for
`-fbounds-safety` the slot is being reserved in this patch.
`SanitizerHandler::BoundsSafety` currently has no uses in the code
but uses will be introduced when the CodeGen side of `-fbounds-safety`'s
implementation is upstreamed.
rdar://126884014
---
clang/lib/CodeGen/CodeGenFunction.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/clang/lib/CodeGen/CodeGenFunction.h
b/clang/lib/CodeGen/CodeGenFunction.h
index 6e7417fc7f52b6..34bdc35d5daffa 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -137,7 +137,8 @@ enum TypeEvaluationKind {
SANITIZER_CHECK(SubOverflow, sub_overflow, 0)
\
SANITIZER_CHECK(TypeMismatch, type_mismatch, 1)
\
SANITIZER_CHECK(AlignmentAssumption, alignment_assumption, 0)
\
- SANITIZER_CHECK(VLABoundNotPositive, vla_bound_not_positive, 0)
+ SANITIZER_CHECK(VLABoundNotPositive, vla_bound_not_positive, 0)
\
+ SANITIZER_CHECK(BoundsSafety, bounds_safety, 0)
enum SanitizerHandler {
#define SANITIZER_CHECK(Enum, Name, Version) Enum,
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