[gjs/wip/ptomato/develop: 1/11] stack: Use js::DumpBacktrace() for gjs_dumpstack()

[Philip Chimento <pchimento src gnome org>]

commit f460a94382f8d4e618a61050261cf9459b0de50f
Author: Philip Chimento <philip chimento gmail com>
Date:   Thu Sep 7 21:11:14 2017 -0700

    stack: Use js::DumpBacktrace() for gjs_dumpstack()
    
    It would be nice to be able to print a JS stack even if the JS engine is
    in the middle of a garbage collection. I have tested and
    js::DumpBacktrace() can do this. The output format is slightly less nice
    but that's OK because gjs_dumpstack() is only for debugging.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=786186

 gi/function.cpp |    6 +-----
 gi/value.cpp    |    6 +-----
 gjs/stack.cpp   |   13 +------------
 3 files changed, 3 insertions(+), 22 deletions(-)
---
diff --git a/gi/function.cpp b/gi/function.cpp
index 21b104d..9a8e72e 100644
--- a/gi/function.cpp
+++ b/gi/function.cpp
@@ -197,11 +197,7 @@ gjs_callback_closure(ffi_cif *cif,
             g_critical("The offending callback was %s()%s.", name,
                        trampoline->is_vfunc ? ", a vfunc" : "");
         }
-        /* A gjs_dumpstack() would be nice here, but we can't,
-           because that works by creating a new Error object and
-           reading the stack property, which is the worst possible
-           idea during a GC session.
-        */
+        gjs_dumpstack();
         gjs_callback_trampoline_unref(trampoline);
         return;
     }
diff --git a/gi/value.cpp b/gi/value.cpp
index bf2ed75..9a4ba93 100644
--- a/gi/value.cpp
+++ b/gi/value.cpp
@@ -154,11 +154,7 @@ closure_marshal(GClosure        *closure,
             g_critical("The offending signal was %s on %s %p.", signal_query.signal_name,
                        g_type_name(G_TYPE_FROM_INSTANCE(instance)), instance);
         }
-        /* A gjs_dumpstack() would be nice here, but we can't,
-           because that works by creating a new Error object and
-           reading the stack property, which is the worst possible
-           idea during a GC session.
-        */
+        gjs_dumpstack();
         return;
     }
 
diff --git a/gjs/stack.cpp b/gjs/stack.cpp
index f71f852..c2c6c0f 100644
--- a/gjs/stack.cpp
+++ b/gjs/stack.cpp
@@ -51,20 +51,9 @@ void
 gjs_context_print_stack_stderr(GjsContext *context)
 {
     JSContext *cx = (JSContext*) gjs_context_get_native_context(context);
-    JS::RootedObject frame(cx);
-    JS::AutoSaveExceptionState exc(cx);
-    GjsAutoChar stack;
 
     g_printerr("== Stack trace for context %p ==\n", context);
-
-    if (!JS::CaptureCurrentStack(cx, &frame) ||
-        !(stack = gjs_format_stack_trace(cx, frame))) {
-        g_printerr("No stack trace available\n");
-        exc.restore();
-        return;
-    }
-
-    g_printerr("%s\n", stack.get());
+    js::DumpBacktrace(cx, stderr);
 }
 
 void