[compiler-rt] 199f7dd - [XRay][X86] Remove sled version 0 support from patchCustomEvent

[Fangrui Song via llvm-commits]

Author: Fangrui Song
Date: 2023-06-19T15:11:26-07:00
New Revision: 199f7dd421e84fb91d2528d30035b3f07af47264

URL: https://github.com/llvm/llvm-project/commit/199f7dd421e84fb91d2528d30035b3f07af47264
DIFF: https://github.com/llvm/llvm-project/commit/199f7dd421e84fb91d2528d30035b3f07af47264.diff

LOG: [XRay][X86] Remove sled version 0 support from patchCustomEvent

This is remnant after D140739.

Added: 
    

Modified: 
    compiler-rt/lib/xray/xray_x86_64.cpp

Removed: 
    


################################################################################
diff  --git a/compiler-rt/lib/xray/xray_x86_64.cpp b/compiler-rt/lib/xray/xray_x86_64.cpp
index 1bf241c1223fc..b9666a40861d4 100644
--- a/compiler-rt/lib/xray/xray_x86_64.cpp
+++ b/compiler-rt/lib/xray/xray_x86_64.cpp
@@ -250,10 +250,8 @@ bool patchCustomEvent(const bool Enable, const uint32_t FuncId,
                       const XRaySledEntry &Sled) XRAY_NEVER_INSTRUMENT {
   // Here we do the dance of replacing the following sled:
   //
-  // In Version 0:
-  //
   // xray_sled_n:
-  //   jmp +20          // 2 bytes
+  //   jmp +15          // 2 bytes
   //   ...
   //
   // With the following:
@@ -262,36 +260,17 @@ bool patchCustomEvent(const bool Enable, const uint32_t FuncId,
   //   ...
   //
   //
-  // The "unpatch" should just turn the 'nopw' back to a 'jmp +20'.
-  //
-  // ---
-  //
-  // In Version 1 or 2:
-  //
-  //   The jump offset is now 15 bytes (0x0f), so when restoring the nopw back
-  //   to a jmp, use 15 bytes instead.
-  //
+  // The "unpatch" should just turn the 'nopw' back to a 'jmp +15'.
   const uint64_t Address = Sled.address();
   if (Enable) {
     std::atomic_store_explicit(
         reinterpret_cast<std::atomic<uint16_t> *>(Address), NopwSeq,
         std::memory_order_release);
   } else {
-    switch (Sled.Version) {
-    case 1:
-    case 2:
-      std::atomic_store_explicit(
-          reinterpret_cast<std::atomic<uint16_t> *>(Address), Jmp15Seq,
-          std::memory_order_release);
-      break;
-    case 0:
-    default:
-      std::atomic_store_explicit(
-          reinterpret_cast<std::atomic<uint16_t> *>(Address), Jmp20Seq,
-          std::memory_order_release);
-      break;
-    }
-    }
+    std::atomic_store_explicit(
+        reinterpret_cast<std::atomic<uint16_t> *>(Address), Jmp15Seq,
+        std::memory_order_release);
+  }
   return false;
 }