822700 - [DMD] DMD-enabled builds running with DMD turned off crash when asked to dump memory reports

Status: RESOLVED FIXED

(Core :: DMD, defect)

Description

[Kartikaya Gupta (email:[e-mail])]

Attachment: backtrace from gdb

I had a fennec build with --enable-dmd running without the DMD=1 environment variable. This meant that DMD was disabled (gDMDEnvVar was 0x0 and gIsDMDRunning was false). When I called nsIMemoryInfoDumper.DumpReportsToFile, it resulted in a crash. Backtrace is attached; it was segfaulting on JS_ASSERT(table) in Hashtable.h because "this" was 0x0 and "table" was garbage.

Comment 1

[Nicholas Nethercote [inactive]]

Attachment: When DMD is disabled its SizeOf() function shouldn't try to measure non-existent structures.

Easy fix.

Comment 2

[Nicholas Nethercote [inactive]]

It'd be nice to have some more comprehensive DMD tests.  Hmm.

Comment 3

[Justin Lebar (not reading bugmail)]

Comment on attachment 693643 [details] [diff] [review]
When DMD is disabled its SizeOf() function shouldn't try to measure non-existent structures.

Could you add a comment indicating that Sizes has a default zeroing constructor so you don't give the next person to read this a heart attack?  :)

r+a=me

Comment 4

[Nicholas Nethercote [inactive]]

> Could you add a comment indicating that Sizes has a default zeroing
> constructor so you don't give the next person to read this a heart attack? 

I added Sizes::Clear() and called it from both the constructor and SizeOf(), to avoid the need for a comment.

https://hg.mozilla.org/integration/mozilla-inbound/rev/a428738147c7

Comment 5

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/a428738147c7

Comment 6

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-aurora/rev/8e0337f05bbf
https://hg.mozilla.org/releases/mozilla-b2g18/rev/8ff7c575a38e