480655 - ATTRCHILD_ARRAY_MAX_CHILD_COUNT is more than mAttrAndChildCount can hold on 64-bit platforms

Status: RESOLVED FIXED

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

Description

[Mats Palmgren (inactive)]

Attachment: Patch rev. 1

Compiling content/base/src/nsAttrAndChildArray.cpp with gcc 4.2.4
on x86_64 Linux:

content/base/src/nsAttrAndChildArray.cpp: In member function 'nsresult nsAttrAndChildArray::InsertChildAt(nsIContent*, PRUint32)':
content/base/src/nsAttrAndChildArray.cpp:169: warning: comparison is always true due to limited range of data type

http://mxr.mozilla.org/mozilla-central/source/content/base/src/nsAttrAndChildArray.cpp#160

In nsAttrAndChildArray.h:
#define ATTRCHILD_ARRAY_MAX_CHILD_COUNT \
    (~PtrBits(0) >> ATTRCHILD_ARRAY_ATTR_SLOTS_BITS)

and in content/base/src/nsAttrValue.h:
typedef unsigned long PtrBits;

so gcc is right, ATTRCHILD_ARRAY_MAX_CHILD_COUNT will always be >
the max value of a PRUint32.

In nsAttrAndChildArray.h, the member holding the bits is defined as:
    PRUint32 mAttrAndChildCount;

Comment 1

[Jonas Sicking (:sicking) No longer reading bugmail consistently]

Comment on attachment 364599 [details] [diff] [review]
Patch rev. 1

Thanks!

Comment 2

[Mats Palmgren (inactive)]

http://hg.mozilla.org/mozilla-central/rev/5cb7c5a0aaf8

-> FIXED