306274 - Nullplugin doesn't work when symbols are hidden by default

Status: RESOLVED DUPLICATE of bug 380984

(Core Graveyard :: Plug-ins, defect)

Description

[Christian :Biesinger (don't email me, ping me on IRC)]

When gcc supports hiding all symbols by default, the null plugin and probably
all other in-tree plugins are broken, because they don't explicitly mark any
symbols as exported. Consequently, the plugin loading code does not find the
symbols it needs (NP_GetMimeDescription et al).

Comment 1

[Philippe M. Chiasson (:gozer)]

Attachment: Patch to make the missing NP_* symbols visible

I've encountered this problem as well, and the attached patch fixes it for me on Fedora Core 4

Comment 2

[Benjamin Smedberg]

Comment on attachment 206731 [details] [diff] [review]
Patch to make the missing NP_* symbols visible

It's not a good idea to mix the NSPR macros in with mozilla code: I suggest using NS_EXPORT_(type) here.

Comment 3

[Christian :Biesinger (don't email me, ping me on IRC)]

bsmedberg: this file is part of the plugin SDK, is it not?

Comment 4

[Benjamin Smedberg]

Does the plugin SDK depend on NSPR but not mozilla?

Comment 5

[Christian :Biesinger (don't email me, ping me on IRC)]

does it depend on NSPR?

Comment 6

[Benjamin Smedberg]

PR_VISIBILITY_DEFAULT sure does...

Comment 7

[Christian :Biesinger (don't email me, ping me on IRC)]

yeah, I think this patch is not good because of that

Comment 8

[Todd Whiteman]

What about using NS_VISIBILITY_DEFAULT and then including "nscore.h" inside npupp.h? Would that work?

Comment 9

[Christian :Biesinger (don't email me, ping me on IRC)]

The question is, is the plugin SDK allowed to depend on NSPR and/or XPCOM?

Comment 10

[Christian :Biesinger (don't email me, ping me on IRC)]

ok, so, npapi.h already includes prtypes.h, so clearly the NSPR dependency is ok. please ignore my comments.

Comment 11

[Todd Whiteman]

Attachment: Updated patch for exporting plugin NP_* symbols

Compiled this on Unix / Windows / Mac (ppc/x86).

Comment 12

[Christian :Biesinger (don't email me, ping me on IRC)]

the comment is wrong... it's not the compiler that has the default visibility, it's mozilla's build system which uses a default visibility of hidden on certain compilers.

Comment 13

[Todd Whiteman]

Attachment: Patch for exposing the plugin symbols, i.e. make symbols visibile

The previous patch did not really work well, so I've changed from using:

#undef  IMETHOD_VISIBILITY
#define IMETHOD_VISIBILITY NS_VISIBILITY_DEFAULT
...
#define IMETHOD_VISIBILITY NS_VISIBILITY_HIDDEN


to use:

NS_VISIBILITY_DEFAULT for each function that needs to be exposed.

Comment 14

[Christian :Biesinger (don't email me, ping me on IRC)]

this got fixed in bug 380984