From 3ac265d5c0e038e324bae29131dbc4bacb4935ea Mon Sep 17 00:00:00 2001
From: hjl-tools <hjl.tools@gmail.com>
Date: Sun, 15 May 2022 18:43:56 -0700
Subject: [PATCH] x86-64: Always double jump table slot size for CET (#710)
 (#711)
 
When CET is enabled, double jump table slot size to add 4 bytes of ENDBR64
for CET.  Since CET enabled clang doesn't have the LLVM assembler bug:
 
https://bugs.llvm.org/show_bug.cgi?id=21501
 
fixed by
 
commit 04d39260d64e08b8bfb3844109ad43d4055b2e8d
Author: Rafael Espindola <rafael.espindola@gmail.com>
Date:   Wed Nov 4 23:50:29 2015 +0000
 
    Simplify .org processing and make it a bit more powerful.
 
we can use .org to allocate jump table slot size to 16 bytes.
 
Conflict:NA
Reference:https://github.com/libffi/libffi/commit/3ac265d5c0e038e324bae29131dbc4bacb4935ea
---
 src/x86/unix64.S | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)
 
diff --git a/src/x86/unix64.S b/src/x86/unix64.S
index 8cf3a23..d9c5bd4 100644
--- a/src/x86/unix64.S
+++ b/src/x86/unix64.S
@@ -39,14 +39,13 @@
    actual table.  The entry points into the table are all 8 bytes.
    The use of ORG asserts that we're at the correct location.  */
 /* ??? The clang assembler doesn't handle .org with symbolic expressions.  */
-#if defined(__clang__) || defined(__APPLE__) || (defined (__sun__) && defined(__svr4__))
+#ifdef __CET__
+/* Double slot size to 16 byte to add 4 bytes of ENDBR64.  */
+# define E(BASE, X)	.balign 8; .org BASE + X * 16
+#elif defined(__clang__) || defined(__APPLE__) || (defined (__sun__) && defined(__svr4__))
 # define E(BASE, X)	.balign 8
 #else
-# ifdef __CET__
-#  define E(BASE, X)	.balign 8; .org BASE + X * 16
-# else
-#  define E(BASE, X)	.balign 8; .org BASE + X * 8
-# endif
+# define E(BASE, X)	.balign 8; .org BASE + X * 8
 #endif
 
 /* ffi_call_unix64 (void *args, unsigned long bytes, unsigned flags,
-- 
2.23.0