GBDJIT: Do not check unwinding information correctness on x64.

src/gdb-jit.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1393 matching lines @@
     AddCode(*name_cstring, *code, GDBJITInterface::FUNCTION, *script);
   } else {
     AddCode("", *code, GDBJITInterface::FUNCTION, *script);
   }
 }
 
 static void AddUnwindInfo(CodeDescription *desc) {
 #ifdef V8_TARGET_ARCH_X64
   if (desc->tag() == GDBJITInterface::FUNCTION) {
     // To avoid propagating unwinding information through
-    // compilation pipeline we rely on function prologue
-    // and epilogue being the same for all code objects generated
-    // by the full code generator.
+    // compilation pipeline we use an approximation.
+    // For most use cases this should not affect usability.
     static const int kFramePointerPushOffset = 1;
     static const int kFramePointerSetOffset = 4;
     static const int kFramePointerPopOffset = -3;
 
     uintptr_t frame_pointer_push_address =
         desc->CodeStart() + kFramePointerPushOffset;
 
     uintptr_t frame_pointer_set_address =
         desc->CodeStart() + kFramePointerSetOffset;
 
     uintptr_t frame_pointer_pop_address =
         desc->CodeEnd() + kFramePointerPopOffset;
 
-#ifdef DEBUG
-    static const uint8_t kFramePointerPushInstruction = 0x48;  // push ebp
-    static const uint16_t kFramePointerSetInstruction = 0x5756;  // mov ebp, esp
-    static const uint8_t kFramePointerPopInstruction = 0xBE;  // pop ebp
-
-    ASSERT(*reinterpret_cast<uint8_t*>(frame_pointer_push_address) ==
-           kFramePointerPushInstruction);
-    ASSERT(*reinterpret_cast<uint16_t*>(frame_pointer_set_address) ==
-           kFramePointerSetInstruction);
-    ASSERT(*reinterpret_cast<uint8_t*>(frame_pointer_pop_address) ==
-           kFramePointerPopInstruction);
-#endif
-
     desc->SetStackStateStartAddress(CodeDescription::POST_RBP_PUSH,
                                     frame_pointer_push_address);
     desc->SetStackStateStartAddress(CodeDescription::POST_RBP_SET,
                                     frame_pointer_set_address);
     desc->SetStackStateStartAddress(CodeDescription::POST_RBP_POP,
                                     frame_pointer_pop_address);
   } else {
     desc->SetStackStateStartAddress(CodeDescription::POST_RBP_PUSH,
                                     desc->CodeStart());
     desc->SetStackStateStartAddress(CodeDescription::POST_RBP_SET,
@@ skipping 99 matching lines @@
                                                GDBJITLineInfo* line_info) {
   ASSERT(!IsLineInfoTagged(line_info));
   HashMap::Entry* e = GetEntries()->Lookup(code, HashForCodeObject(code), true);
   ASSERT(e->value == NULL);
   e->value = TagLineInfo(line_info);
 }
 
 
 } }  // namespace v8::internal
 #endif