682946 - GCC 4.6 build warning: "nsJSEnvironment.cpp:2248:12: warning: variable 'flags' set but not used [-Wunused-but-set-variable]"

Status: RESOLVED FIXED

(Core :: DOM: Core & HTML, defect)

Description

[Daniel Holbert [:dholbert]]

Filing bug on this build warning, seen in GCC 4.6 on x86_64 linux:

/mozilla/dom/base/nsJSEnvironment.cpp: In member function 'virtual nsresult nsJSContext::CreateOuterObject(nsIScriptGlobalObject*, nsIScriptGlobalObject*)':
/mozilla/dom/base/nsJSEnvironment.cpp:2248:12: warning: variable 'flags' set but not used [-Wunused-but-set-variable]

The code in question:
> 2241 nsresult
> 2242 nsJSContext::CreateOuterObject(nsIScriptGlobalObject *aGlobalObject,
> 2243                                nsIScriptGlobalObject *aCurrentInner)
> 2244 {
[...]
> 2248   PRUint32 flags = 0;
> 2249 
> 2250   if (chromeWindow) {
> 2251     // Flag this window's global object and objects under it as "system",
> 2252     // for optional automated XPCNativeWrapper construction when chrome JS
> 2253     // views a content DOM.
> 2254     flags = nsIXPConnect::FLAG_SYSTEM_GLOBAL_OBJECT;

It looks like we're expecting |flags| to have an effect, but clearly (per the GCC warning) its value is never read.

This changed here, as part of bug 586083:
https://hg.mozilla.org/mozilla-central/diff/ad65187427e8/dom/base/nsJSEnvironment.cpp#l1.91

That cset removed the only use of |flags| -- specifically, it replaced a call to...
  xpc->InitClassesWithNewWrappedGlobal(..., flags, ...)
...with...
  xpc->WrapNative(...)

mrbkap: Do you know if we still should be using |flags| at all, or if we can just drop it entirely?

Comment 1

[Blake Kaplan (:mrbkap) (inactive)]

We can drop it entirely. I'll have a patch in a second.

Comment 2

[Blake Kaplan (:mrbkap) (inactive)]

Attachment: patch

Comment 3

[Ed Morley [:emorley]]

http://hg.mozilla.org/mozilla-central/rev/3a37edcaa27f