Simd features on specific files - cannot enable exceptions

[manoh]

Hi,

i want to enable sse and avx just for specific source files. This works, but i'm using on some other files exceptions and i cannot prevent qmake to not generate CXXFlags with -fno_exceptions. If i delete -fno_expcetions at the generated makefile the static lib does compile at all.

My pro-file looks like this:

# target should be a non-qt static lib
CONFIG -= qt
CONFIG += staticlib
CONFIG += warn_on c++11 debug_and_release exceptions simd

TEMPLATE = lib
TAREGET = mylibrary

INCLUDEPATH += include 

SSE2_SOURCES += fooSse2.cpp

AVX2_SOURCES +=fooAvx2.cpp

SOURCES += bar.cpp

Does somebody know why i cannot enable exceptions???

[kshegunov]

@manoh
I don't think this flag is at all relevant for static libraries. What happens when you actually link the static lib with CONFIG += exceptions ion your project?

[manoh]

@kshegunov

The static lib does not compile: -fno_exceptions

Compiler output:

/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++ -c -pipe -stdlib=libc++ -O2 -fPIC -std=gnu++11 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk -mmacosx-version-min=10.7 -Wall -W -fno-exceptions -DQT_NO_MTDEV -DQT_NO_LIBUDEV -DQT_NO_EVDEV -DQT_NO_TSLIB -DQT_NO_LIBINPUT -DQT_NO_EXCEPTIONS -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -I../../../lib/libimagedecoder -I. -I../../../lib/include -I../../../lib/src -I../../../lib/other_headers -I/usr/local/opt/openssl/include -I/Users/asdf/Qt/5.6/clang_64/mkspecs/macx-clang -o .obj/IImageDecoder.o ../../../lib/foo.cpp
../../../lib/foo.cpp:123:6: error: cannot use 'throw' with
      exceptions disabled
                                        throw std::invalid_argument("The given arguments to ..."
                                        ^
../../../lib/foo.cpp:203:6: error: cannot use 'throw' with
      exceptions disabled
                                        throw std::invalid_argument("The given arguments to ..."
                                        ^
2 errors generated.

[kshegunov]

@manoh said:

The static lib does not compile: -fno_exceptions

I see. Perhaps I'm in error, it's been known to happen. They should be enabled by default (as per the qmake docs`), but try something like this:

CONFIG -= qt exceptions_off
CONFIG += staticlib
CONFIG += warn_on c++11 debug_and_release exceptions simd

As a side question, what version of Qt (hence qmake) are you using?

Kind regards.

[manoh]

@kshegunov

Thanks for answers!

I tried this before i wrote my first post and this does not work :-( I think i have to write a custom compiler (after the weekend).

$ qmake -v
QMake version 3.0
Using Qt version 5.6.0 in /Users/asdf/Qt/5.6/clang_64/lib

[kshegunov]

@manoh
I can reproduce this on Linux, so it's probably a bug in qmake. Do you mind reporting it on the bugtracker?

[manoh]

@kshegunov

I'm not sure if this is bug or if i cannot use simd config-option this way.

[kshegunov]

@manoh
I didn't use simd for my tests, only the excetpions/exceptions_off options.

I'm just getting forgetful in my old age. I did use simd, removing it fixes the issue. Where did that configuration option came from anyway?

[manoh]

@kshegunov
I searched on the internet and read some threads, documentation and source code...
At least i was grepping at Qt/5.6/Src/qtbase/src/gui for simd
There is QMAKESPEC file at mkspecs/features/simd.prf

[kshegunov]

@manoh
To be honest I don't know if this is a bug, or expected behaviour. I advise asking on the interest mailing list how/if you can use that config option. Sorry, I couldn't be of more help.

Kind regards.