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

src/builtins.cc

Index: src/builtins.cc
===================================================================
--- src/builtins.cc	(revision 6445)
+++ src/builtins.cc	(working copy)
@@ -1494,6 +1494,20 @@
       GDBJIT(AddCode(GDBJITInterface::BUILTIN,
                      functions[i].s_name,
                      Code::cast(code)));
+      {
+        ZoneScope uinfo(DELETE_ON_EXIT);

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

Do we really need this piece of code?

The code stub was registered above as GDBJITInterface::CodeTag::BUILTIN so
GDBJIT really knows how to handle it.

+        uintptr_t begin = reinterpret_cast<uintptr_t>
+                          (Code::cast(code)->instruction_start());
+        uintptr_t size = Code::cast(code)->instruction_size();
+
+        // This is to prevent compiler errors about begin and end not being
+        // used when SET_UNWIND_INFO_STUB is empty.
+
+        (void) begin;
+        (void) size;
+        SET_UNWIND_INFO_STUB(begin, size);
+      }
+
       builtins_[i] = code;
 #ifdef ENABLE_DISASSEMBLER
       if (FLAG_print_builtin_code) {