1 files changed, 69 insertions, 0 deletions
diff --git a/js/src/gdb/mozilla/jsid.py b/js/src/gdb/mozilla/jsid.py
new file mode 100644
index 000000000..b7c0e183b
--- /dev/null
+++ b/js/src/gdb/mozilla/jsid.py
@@ -0,0 +1,69 @@
+# Pretty-printers for JSID values.
+
+import gdb
+import mozilla.prettyprinters
+import mozilla.Root
+
+from mozilla.prettyprinters import pretty_printer
+
+# Forget any printers from previous loads of this module.
+mozilla.prettyprinters.clear_module_printers(__name__)
+
+@pretty_printer('jsid')
+class jsid(object):
+    # Since people don't always build with macro debugging info, I can't
+    # think of any way to avoid copying these values here, short of using
+    # inferior calls for every operation (which, I hear, is broken from
+    # pretty-printers in some recent GDBs).
+    TYPE_STRING                 = 0x0
+    TYPE_INT                    = 0x1
+    TYPE_VOID                   = 0x2
+    TYPE_SYMBOL                 = 0x4
+    TYPE_MASK                   = 0x7
+
+    def __init__(self, value, cache):
+        self.value = value
+        self.cache = cache
+        self.concrete_type = self.value.type.strip_typedefs()
+
+    # SpiderMonkey has two alternative definitions of jsid: a typedef for
+    # ptrdiff_t, and a struct with == and != operators defined on it.
+    # Extract the bits from either one.
+    def as_bits(self):
+        if self.concrete_type.code == gdb.TYPE_CODE_STRUCT:
+            return self.value['asBits']
+        elif self.concrete_type.code == gdb.TYPE_CODE_INT:
+            return self.value
+        else:
+            raise RuntimeError("definition of SpiderMonkey 'jsid' type"
+                               "neither struct nor integral type")
+
+    def to_string(self):
+        bits = self.as_bits()
+        tag = bits & jsid.TYPE_MASK
+        if tag == jsid.TYPE_STRING:
+            body = bits.cast(self.cache.JSString_ptr_t)
+        elif tag & jsid.TYPE_INT:
+            body = bits >> 1
+        elif tag == jsid.TYPE_VOID:
+            return "JSID_VOID"
+        elif tag == jsid.TYPE_SYMBOL:
+            if bits == jsid.TYPE_SYMBOL:
+                return "JSID_EMPTY"
+            body = ((bits & ~jsid.TYPE_MASK)
+                    .cast(self.cache.JSSymbol_ptr_t))
+        else:
+            body = "<unrecognized>"
+        return '$jsid(%s)' % (body,)
+
+# Hard-code the referent type pretty-printer for jsid roots and handles.
+# See the comment for mozilla.Root.Common.__init__.
+@pretty_printer('JS::Rooted<long>')
+def RootedJSID(value, cache):
+    return mozilla.Root.Rooted(value, cache, jsid)
+@pretty_printer('JS::Handle<long>')
+def HandleJSID(value, cache):
+    return mozilla.Root.Handle(value, cache, jsid)
+@pretty_printer('JS::MutableHandle<long>')
+def MutableHandleJSID(value, cache):
+    return mozilla.Root.MutableHandle(value, cache, jsid)