487428 - TraceMonkey: Forcing platform features using NJ_FORCE_* causes the build to fail.

Status: RESOLVED WONTFIX

(Core :: JavaScript Engine, defect)

Description

[Jacob Bramley [:jbramley]]

Attachment: Fix feature detection code to be tolerant of forced values.

js/src/nanojit/avmplus.h allows NJ_FORCE_* to force certain configuration parameters. However, actually specifying one of these causes the build to fail because these values are written to in js/src/jstracer.cpp and they are declared as const when NJ_FORCE_* is in effect.

The attached patch fixes this by added pre-processor guards in js/src/jstracer.cpp.

Note: This patch builds on my patch for bug 487416.

Comment 1

[Serge Gautherie (:sgautherie)]

Should this land in tm or m-c?

Comment 2

[Phil Ringnalda (:philor)]

Land it in tracemonkey or wontfix it, don't just leave it in purgatory.

Comment 3

[Jacob Bramley [:jbramley]]

Interesting. I thought this was pushed, but clearly nobody uses the NJ_FORCE flags else it would really have been pushed.

Now that the back-ends are merged, this get interesting. Tamarin doesn't do run-time detection, and doesn't use AvmCore::config for this stuff, so is this code only run by Trace Monkey? It's tempting to simply remove the NJ_FORCE support. We can now use lirasm to test code-paths anyway, and will we ever want to produce a build of Trace Monkey that does not do run-time feature detection? I suppose not, but I'd rather hear that from someone who really knows rather than supposes.

Comment 4

[Nochum Sossonko [:Natch]]

These bugs are all part of a search I made for js bugs that are getting lost in
transit:

http://tinyurl.com/jsDeadEndBugs

They all have a review+'ed, non-obsoleted patch and are not marked
fixed-in-tracemonkey or checkin-needed but have not seen any activity in 300
days. Some of these got lost simply because the assignee/patch provider never
requested a checkin, or just because they were forgotten about.

Comment 5

[Nicholas Nethercote [inactive]]

grep tells me that NJ_FORCE_* doesn't exist any more.