[compiler-rt] [win/asan] GetInstructionSize: Make `F6 C1 XX` a generic entry. (PR #118144)

[via llvm-commits]

https://github.com/bernhardu updated https://github.com/llvm/llvm-project/pull/118144

>From 82ff530cbde0395b6580c5a3e00bd05f5b78ee20 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bernhard=20=C3=9Cbelacker?= <bernhardu at mailbox.org>
Date: Sat, 30 Nov 2024 22:00:35 +0100
Subject: [PATCH] [win/asan] GetInstructionSize: Make `F6 C1 XX` a generic
 entry.

---
 compiler-rt/lib/interception/interception_win.cpp           | 6 ++++--
 .../lib/interception/tests/interception_win_test.cpp        | 1 +
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/compiler-rt/lib/interception/interception_win.cpp b/compiler-rt/lib/interception/interception_win.cpp
index 93886e79fd88c8..a581b720a34bc1 100644
--- a/compiler-rt/lib/interception/interception_win.cpp
+++ b/compiler-rt/lib/interception/interception_win.cpp
@@ -634,6 +634,9 @@ static size_t GetInstructionSize(uptr address, size_t* rel_offset = nullptr) {
     case 0xD284:  // 84 D2 : test dl,dl
       return 2;
 
+    case 0xC1F6:  // F6 C1 XX : test cl, XX
+      return 3;
+
     // Cannot overwrite control-instruction. Return 0 to indicate failure.
     case 0x25FF:  // FF 25 XX YY ZZ WW : jmp dword ptr ds:[WWZZYYXX]
       return 0;
@@ -723,8 +726,7 @@ static size_t GetInstructionSize(uptr address, size_t* rel_offset = nullptr) {
       return 7;
   }
 
-  switch (0x00FFFFFF & *(u32*)address) {
-    case 0x07c1f6:    // f6 c1 07 : test cl, 0x7
+  switch (0x00FFFFFF & *(u32 *)address) {
     case 0x10b70f:    // 0f b7 10 : movzx edx, WORD PTR [rax]
     case 0xc00b4d:    // 4d 0b c0 : or r8, r8
     case 0xc03345:    // 45 33 c0 : xor r8d, r8d
diff --git a/compiler-rt/lib/interception/tests/interception_win_test.cpp b/compiler-rt/lib/interception/tests/interception_win_test.cpp
index 3c60d9c6f49df9..d9f91f6a4bc0ae 100644
--- a/compiler-rt/lib/interception/tests/interception_win_test.cpp
+++ b/compiler-rt/lib/interception/tests/interception_win_test.cpp
@@ -927,6 +927,7 @@ const struct InstructionSizeData {
     { 3, {0x4d, 0x85, 0xed}, 0, "4d 85 ed : test r13, r13"},
     { 3, {0x4d, 0x85, 0xf6}, 0, "4d 85 f6 : test r14, r14"},
     { 3, {0x4d, 0x85, 0xff}, 0, "4d 85 ff : test r15, r15"},
+    { 3, {0xf6, 0xc1, 0x72}, 0, "f6 c1 XX : test cl, XX"},
     { 4, {0x44, 0x0f, 0xb6, 0x1a}, 0, "44 0f b6 1a : movzx r11d, BYTE PTR [rdx]"},
     { 4, {0x44, 0x8d, 0x42, 0x73}, 0, "44 8d 42 XX : lea r8d , [rdx + XX]"},
     { 4, {0x48, 0x83, 0xec, 0x73}, 0, "48 83 ec XX : sub rsp, XX"},