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

src/x64/full-codegen-x64.cc

Index: src/x64/full-codegen-x64.cc
===================================================================
--- src/x64/full-codegen-x64.cc	(revision 6445)
+++ src/x64/full-codegen-x64.cc	(working copy)
@@ -69,7 +69,9 @@
   }
 #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.
 
@@ -245,7 +247,9 @@
     // 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