791138 - SPSProfiler.cpp:410:73: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Daniel Holbert [:dholbert]]

Reporting build warning:
{
../../../mozilla/js/src/vm/SPSProfiler.cpp: In member function ‘jsbytecode* js::ProfileEntry::pc() volatile’:
../../../mozilla/js/src/vm/SPSProfiler.cpp:410:73: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
}

The line of code is:
> 410     JS_ASSERT_IF(idx != NullPCIndex, idx >= 0 && idx < script()->length);
https://mxr.mozilla.org/mozilla-central/source/js/src/vm/SPSProfiler.cpp#410

I don't immediately see where idx is declared, but it appears to be signed (since we bother comparing it >= 0), and JSScript::length is unsigned (uint32_t)
  https://mxr.mozilla.org/mozilla-central/source/js/src/jsscript.h#369
...so that last comparison is the source of this warning:
 "idx < script()->length"

We can just cast idx to uint32_t there, since we've already checked that it's non-negative.

Comment 1

[Daniel Holbert [:dholbert]]

Attachment: fix

Comment 2

[Nicholas Nethercote [inactive]]

I fixed this in bug 791608.