Cleanup: prevent USD exports from leaking into blender binary.
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Authored by Ray Molenkamp (LazyDodo) on Jan 11 2020, 10:38 PM.

Details

Reviewers

Sybren A. Stüvel (sybren)
Sergey Sharybin (sergey)

Commits

rB4db9562246b3: libs/windows: Prevent USD exports from leaking into blender binary.
rB86db35845a83: libs/windows: Prevent USD exports from leaking into blender binary.

Summary

Even though we build USD as static, it still feels the need to mark its
symbols with declspec(dllexport) which means the blender binary now exports
these symbols.

now this isn't necessarily harmful there is no reason to be sloppy and
export symbols that have no business getting exported.

This patch fixes the behavior for USD which was by far the worst offender
in this area with 6137 exports. However that doesn't mean the other libs
that exhibit this behavior get a free pass, they too will be dealt with.

Before:

exports_orig.txt3 MBDownload

After:

exports_new.txt455 KBDownload

Diff Detail

Repository

rB Blender

Branch

tmp_fix_usd_exports (branched from master)

Build Status

Buildable 6220
Build 6220: arc lint + arc unit

Event Timeline

Ray Molenkamp (LazyDodo) created this revision.Jan 11 2020, 10:38 PM

Harbormaster completed remote builds in B6220: Diff 20730.Jan 11 2020, 10:39 PM

Ray Molenkamp (LazyDodo) edited the summary of this revision. (Show Details)Jan 11 2020, 10:40 PM

noki paike (amonpaike) awarded a token.Jan 12 2020, 9:01 AM

Sybren A. Stüvel (sybren) added inline comments.Jan 13 2020, 5:28 PM

build_files/build_environment/patches/usd.diff
122–124	Is this really only an issue on Windows? Or should we do something about this on other platforms as well?

I don't think it matters all that much on other platforms, it's always been a wild west regarding symbol exports on linux

There is a fundamentally different philosophy between the platforms:

with msvc default is : DO NOT EXPORT, if you want to export a symbol from a dynamic library, you have to explicitly request it by tagging on declspec(dllexport) . If you want to export all symbols, the compiler literally won't let you, cmake has an optional hack to work around this if you are so inclined.
with gcc had they for the longest time this approach: EXPORT ALL THE THINGS!! while hiding symbols has become more common (gcc wiki here, and USD ticket regarding it not working here ) the default afaik still is 'export all' unless you pass -fvisibility=hidden

I'd say it's up to the platform dev to decide if this is an issue for them or not.

Judging by the hacks already in place to make it build this (monolithic static) is clearly not a tested scenario for upstream, so i just stuck it in a win32 if not to bother the other platforms.

Sybren A. Stüvel (sybren) accepted this revision.Jan 14 2020, 12:44 PM

This revision is now accepted and ready to land.Jan 14 2020, 12:44 PM

Ray Molenkamp (LazyDodo) mentioned this in D6593: Build: upgrade to OpenEXR 2.4.0, OpenVDB 7.0.0 and Boost 1.70.0.Jan 16 2020, 8:02 PM

Closed by commit rB86db35845a83: libs/windows: Prevent USD exports from leaking into blender binary. (authored by Ray Molenkamp (LazyDodo)). · Explain WhyJan 16 2020, 9:11 PM

This revision was automatically updated to reflect the committed changes.

Ray Molenkamp (LazyDodo) added a commit: rB86db35845a83: libs/windows: Prevent USD exports from leaking into blender binary..

Ray Molenkamp (LazyDodo) added a commit: rB4db9562246b3: libs/windows: Prevent USD exports from leaking into blender binary..Jan 21 2020, 5:47 PM

Ray Molenkamp (LazyDodo) mentioned this in D6645: Deps: Bump freetype to 2.10.1.Jan 21 2020, 10:03 PM

Ray Molenkamp (LazyDodo) mentioned this in D6646: deps:Fix unwanted exports from libxml.Jan 21 2020, 10:54 PM

Ray Molenkamp (LazyDodo) mentioned this in D6647: Fix: oidn exporting its symbols in blender..Jan 21 2020, 11:20 PM

Ray Molenkamp (LazyDodo) mentioned this in T73296: Blender starts on slower GPU, interface and 3D viewport laggy.Jan 23 2020, 10:54 PM

Jeroen Bakker (jbakker) awarded a token.Jan 24 2020, 10:39 AM