Ensures that GDB prints stacktraces correctly for x64 builds when debugging t...

src/x64/full-codegen-x64.cc

 // Copyright 2011 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 51 matching lines @@
   SetFunctionPosition(function());
   Comment cmnt(masm_, "[ function compiled by full code generator");
 
 #ifdef DEBUG
   if (strlen(FLAG_stop_at) > 0 &&
       info->function()->name()->IsEqualTo(CStrVector(FLAG_stop_at))) {
     __ int3();
   }
 #endif
   __ push(rbp);  // Caller's frame pointer.
+  SET_UNWIND_INFO(UNWIND_STATE_AFTER_RBP_PUSH, masm_->pc_offset());

[Vyacheslav Egorov (Chromium), 2011/01/25 12:50:11]

The idea is to keep GDBJIT as isolated as possible we do not want to obscure
codegeneration with calls to GDBJIT if it is possible.

PC offsets for UNWIND_STATE will almost fixed for all functions generated by
fullcodegen. So it seems possible to move this completely to gdb-jit.cc.

   __ movq(rbp, rsp);
+  SET_UNWIND_INFO(UNWIND_STATE_AFTER_RBP_SET, masm_->pc_offset());
   __ push(rsi);  // Callee's context.
   __ push(rdi);  // Callee's JS Function.
 
   { Comment cmnt(masm_, "[ Allocate locals");
     int locals_count = scope()->num_stack_slots();
     if (locals_count == 1) {
       __ PushRoot(Heap::kUndefinedValueRootIndex);
     } else if (locals_count > 1) {
       __ LoadRoot(rdx, Heap::kUndefinedValueRootIndex);
       for (int i = 0; i < locals_count; i++) {
@@ skipping 155 matching lines @@
     // Add a label for checking the size of the code used for returning.
     Label check_exit_codesize;
     masm_->bind(&check_exit_codesize);
 #endif
     CodeGenerator::RecordPositions(masm_, function()->end_position() - 1);
     __ RecordJSReturn();
     // Do not use the leave instruction here because it is too short to
     // patch with the code required by the debugger.
     __ movq(rsp, rbp);
     __ pop(rbp);
+    SET_UNWIND_INFO(UNWIND_STATE_AFTER_RBP_POP, masm_->pc_offset());
     __ ret((scope()->num_parameters() + 1) * kPointerSize);
+    SET_UNWIND_INFO(UNWIND_STATE_AFTER_RETURN, masm_->pc_offset());
 #ifdef ENABLE_DEBUGGER_SUPPORT
     // Add padding that will be overwritten by a debugger breakpoint.  We
     // have just generated "movq rsp, rbp; pop rbp; ret k" with length 7
     // (3 + 1 + 3).
     const int kPadding = Assembler::kJSReturnSequenceLength - 7;
     for (int i = 0; i < kPadding; ++i) {
       masm_->int3();
     }
     // Check that the size of the code used for returning matches what is
     // expected by the debugger.
@@ skipping 3383 matching lines @@
   __ ret(0);
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64