AVX Feature Detection in GCC Release corrupts something (but what?)

[tank-trax]

@baconpaul editing this issue at the top

Basically a release build of xt blows up on the about screen. The reason is because the about screen asks if the cpu has AVX support to decorate the about info. For some reason gcc release code and our implementation of hasAVX corrupts memory somehow (how?). So for now I made hasAVX always return true. But clearly this isn't OK and we need it to actually detect without blowing up stuff so renaming this issue and leaving it open.

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This is the command line output for Debug that can open About screen

JUCE v6.0.7
SurgeXT Startup
  - Version    : 1.0.main.877ba210
  - Build Info : x86_64 GNU-10.2.1
  - Build Time : 2021-05-06 23:08:06
  - CPU        :  Intel(R) Core(TM) i5-3470 CPU @ 3.20GHz

PatchDB : Opening sqlitedb /home/studio/Documents/Surge/SurgePatches.db
        : schema check. DBVersion='2' SchemaVersion='2'
        : Schema matches. Reusing database.
SynthProcessor: /home/studio/dev/extras/surge-xt/src/surge_synth_juce/SurgeSynthStandaloneExtensions.cpp
JUCE Assertion failure in juce_PathStrokeType.cpp:267
JUCE Assertion failure in juce_PathStrokeType.cpp:267
  - efvg unimplemented : getViewAt at /home/studio/dev/extras/surge-xt/libs/escape-from-vstgui/include/efvg/escape_from_vstgui.h:1154
SynthEditor: /home/studio/dev/extras/surge-xt/src/surge_synth_juce/SurgeSynthStandaloneExtensions.cpp
  - efvg unimplemented : getViewAt at /home/studio/dev/extras/surge-xt/libs/escape-from-vstgui/include/efvg/escape_from_vstgui.h:1154
  - efvg unimplemented : localToFrame at /home/studio/dev/extras/surge-xt/libs/escape-from-vstgui/include/efvg/escape_from_vstgui.h:1289
  - efvg unimplemented : isChild at /home/studio/dev/extras/surge-xt/libs/escape-from-vstgui/include/efvg/escape_from_vstgui.h:1159
  - efvg unimplemented : localToFrame at /home/studio/dev/extras/surge-xt/libs/escape-from-vstgui/include/efvg/escape_from_vstgui.h:1289
  - efvg unimplemented : isChild at /home/studio/dev/extras/surge-xt/libs/escape-from-vstgui/include/efvg/escape_from_vstgui.h:1159

and for Release that segfaults when About is opened (you can see I opened and closed it twice)

./Surge\ XT 
SurgeXT Startup
  - Version    : 1.0.main.877ba210
  - Build Info : x86_64 GNU-10.2.1
  - Build Time : 2021-05-06 22:24:30
  - CPU        :  Intel(R) Core(TM) i5-3470 CPU @ 3.20GHz

PatchDB : Opening sqlitedb /home/studio/Documents/Surge/SurgePatches.db
        : schema check. DBVersion='2' SchemaVersion='2'
        : Schema matches. Reusing database.
SynthProcessor: /home/studio/dev/extras/surge-xt/src/surge_synth_juce/SurgeSynthStandaloneExtensions.cpp
  - efvg unimplemented : getViewAt at /home/studio/dev/extras/surge-xt/libs/escape-from-vstgui/include/efvg/escape_from_vstgui.h:1154
SynthEditor: /home/studio/dev/extras/surge-xt/src/surge_synth_juce/SurgeSynthStandaloneExtensions.cpp
  - efvg unimplemented : getViewAt at /home/studio/dev/extras/surge-xt/libs/escape-from-vstgui/include/efvg/escape_from_vstgui.h:1154
  - efvg unimplemented : localToFrame at /home/studio/dev/extras/surge-xt/libs/escape-from-vstgui/include/efvg/escape_from_vstgui.h:1289
free(): invalid pointer
Aborted

[tank-trax]

Debian Bullseye 11

[tank-trax]

here's the Debug running on Mint 19

[ghost]

Compilers...
Release build with Clang-12.0.1 : all good
with gcc i get the same as @tank-trax
Debug build with gcc 9.3.0 : all good
Release build with gcc 9.3.0 : crash when click on about
gdb says this:
crash_gcc_Release.txt
(all Mint 20.1 / Standalone at 877ba21)

[baconpaul]

Very useful thanks. I will take a peek

[baconpaul]

OK I'm pushing a workaround for this and re-naming this issue to the root cause. More in a second.

[baconpaul]

Got it. merge shortly.