[compiler-rt] [win/asan] GetInstructionSize: Support `48 bX` movabsq instructions. (PR #141625)

[via llvm-commits]

https://github.com/bernhardu created https://github.com/llvm/llvm-project/pull/141625

Created for Wine's memset by clang or mingw-gcc,
the latter places it quite at the start of the function:

```
   0x00006ffffb67e210 <memset+0>:       0f b6 d2                movzbl %dl,%edx
   0x00006ffffb67e213 <memset+3>:       48 b8 01 01 01 01 01 01 01 01   movabs $0x101010101010101,%rax
```

`3200      uint64_t v = 0x101010101010101ull * (unsigned char)c;`

https://gitlab.winehq.org/wine/wine/-/blob/290fd532ee7376442d272e3833528256bfe5e9dc/dlls/msvcrt/string.c#L3200

>From 284efe84fd776a1a784356239faef4741279081c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bernhard=20=C3=9Cbelacker?= <bernhardu at mailbox.org>
Date: Tue, 27 May 2025 17:08:32 +0200
Subject: [PATCH] [win/asan] GetInstructionSize: Support `48 bX` movabsq
 instructions.

Created for Wine's memset by clang or mingw-gcc,
the latter places it quite at the start of the function:

```
   0x00006ffffb67e210 <memset+0>:       0f b6 d2                movzbl %dl,%edx
   0x00006ffffb67e213 <memset+3>:       48 b8 01 01 01 01 01 01 01 01   movabs $0x101010101010101,%rax
```

`3200      uint64_t v = 0x101010101010101ull * (unsigned char)c;`

https://gitlab.winehq.org/wine/wine/-/blob/290fd532ee7376442d272e3833528256bfe5e9dc/dlls/msvcrt/string.c#L3200
---
 compiler-rt/lib/interception/interception_win.cpp           | 6 ++++++
 .../lib/interception/tests/interception_win_test.cpp        | 2 ++
 2 files changed, 8 insertions(+)

diff --git a/compiler-rt/lib/interception/interception_win.cpp b/compiler-rt/lib/interception/interception_win.cpp
index c9a77180014c4..246a22c56c31a 100644
--- a/compiler-rt/lib/interception/interception_win.cpp
+++ b/compiler-rt/lib/interception/interception_win.cpp
@@ -754,6 +754,12 @@ static size_t GetInstructionSize(uptr address, size_t* rel_offset = nullptr) {
     case 0x7B81:  // 81 7B YY XX XX XX XX  cmp DWORD PTR [rbx+YY], XX XX XX XX
     case 0x7981:  // 81 79 YY XX XX XX XX  cmp dword ptr [rcx+YY], XX XX XX XX
       return 7;
+
+    case 0xb848:  // 48 b8 XX XX XX XX XX XX XX XX :
+                  //   movabsq XX XX XX XX XX XX XX XX, rax
+    case 0xba48:  // 48 ba XX XX XX XX XX XX XX XX :
+                  //   movabsq XX XX XX XX XX XX XX XX, rdx
+      return 10;
   }
 
   switch (0x00FFFFFF & *(u32 *)address) {
diff --git a/compiler-rt/lib/interception/tests/interception_win_test.cpp b/compiler-rt/lib/interception/tests/interception_win_test.cpp
index 893f346d73b8a..f11c1d1458556 100644
--- a/compiler-rt/lib/interception/tests/interception_win_test.cpp
+++ b/compiler-rt/lib/interception/tests/interception_win_test.cpp
@@ -1043,6 +1043,8 @@ const struct InstructionSizeData {
     { 8, {0xc7, 0x44, 0x24, 0x73, 0x74, 0x75, 0x76, 0x77}, 0, "C7 44 24 XX YY YY YY YY : mov dword ptr [rsp + XX], YYYYYYYY"},
     { 9, {0x41, 0x81, 0x7c, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78}, 0, "41 81 7c ZZ YY XX XX XX XX : cmp DWORD PTR [reg+reg*n+YY], XX XX XX XX"},
     { 9, {0xA1, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78}, 0, "A1 XX XX XX XX XX XX XX XX : movabs eax, dword ptr ds:[XXXXXXXX]"},
+    {10, {0x48, 0xb8, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79}, 0, "48 b8 XX XX XX XX XX XX XX XX : movabsq XX XX XX XX XX XX XX XX, rax"},
+    {10, {0x48, 0xba, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79}, 0, "48 ba XX XX XX XX XX XX XX XX : movabsq XX XX XX XX XX XX XX XX, rdx"},
 #else
     // sorted list
     { 3, {0x8B, 0x45, 0x72}, 0, "8B 45 XX : mov eax, dword ptr [ebp + XX]"},