qt creator - breakpoints don't work

[pmitas]

I've kind of tracked down the issue - qtcreator doesn't add -g option to CFLAGS when building in debug mode. In fact it doesn't add any optimization options when building in release mode either...

Here's a build line in debug mode:

g++ -c -pipe -Wall -W -D_REENTRANT -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/usr/share/qt4/mkspecs/linux-g++ -I. -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtGui -I/usr/include/qt4 -I. -I. -o main.o main.cpp

g++ -c -pipe -Wall -W -D_REENTRANT -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/usr/share/qt4/mkspecs/linux-g++ -I. -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtGui -I/usr/include/qt4 -I. -I. -o main.o main.cpp

To copy to clipboard, switch view to plain text mode 

ant this is in release mode:

g++ -c -pipe -Wall -W -D_REENTRANT -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/usr/share/qt4/mkspecs/linux-g++ -I. -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtGui -I/usr/include/qt4 -I. -I. -o main.o main.cpp

g++ -c -pipe -Wall -W -D_REENTRANT -DQT_NO_DEBUG -DQT_GUI_LIB -DQT_CORE_LIB -DQT_SHARED -I/usr/share/qt4/mkspecs/linux-g++ -I. -I/usr/include/qt4/QtCore -I/usr/include/qt4/QtGui -I/usr/include/qt4 -I. -I. -o main.o main.cpp

To copy to clipboard, switch view to plain text mode 

The only difference is -DQT_NO_DEBUG.

I clearly remember, that this stuff used to work in the past. What could have happened that broke it?

[tbscope]

As a side note, and one I did encounter.
Do not use-o optimisation and -g dwarf information at the same time.

Some breakpoints will fail because the code is optimised.
A debugger making use of the dwarf information will not report the correct line numbers. It will report line numbers of the optimised code.

[pmitas]

Oddly, I rebuilt qt-core (I'm on Gentoo) without optimized-qmake and it started including -g in debug mode, but still is not doing any optimizations in release mode.

I did some snooping around and found the file /usr/share/qt4/mkspecs/common/g++.conf. There I found the lines:

QMAKE_CFLAGS_RELEASE    +=
QMAKE_CFLAGS_DEBUG      += -g

QMAKE_CFLAGS_RELEASE    +=
QMAKE_CFLAGS_DEBUG      += -g

To copy to clipboard, switch view to plain text mode 

Should the first line be empty?

[tbscope]

Did you recently change /etc/make.conf ?
On my system it contains the CXX_FLAGS (or something like that) environment variable.

Edit: note that optimisation isn't always wanted, so you should set the level yourself.

[pmitas]

No, I didn't change /etc/make.conf C(XX)FLAGS lately. It's set to:

CFLAGS="-O2 -march=core2 -msse3 -mssse3 -msse4.1 -pipe -g"
CXXFLAGS="${CFLAGS}"

CFLAGS="-O2 -march=core2 -msse3 -mssse3 -msse4.1 -pipe -g"
CXXFLAGS="${CFLAGS}"

To copy to clipboard, switch view to plain text mode 

I also remember, that in the past the release mode used some or all of these flags.

[wysota]

I don't think qmake takes /etc/make.conf into consideration when generating the Makefile. It should work solely based upon $QTDIR/mkspecs/*.

[pmitas]

Well then, should the QMAKE_CFLAGS_RELEASE variable be empty?

[wysota]

I think you should care more about QMAKE_CXXFLAGS and family.

[pmitas]

I think you should care more about QMAKE_CXXFLAGS and family.

This one's set to just "-pipe".

[wysota]

What about QMAKE_CXXFLAGS_DEBUG and others like it?

[pmitas]

Here are all the defaults:

QMAKE_CC                = gcc
QMAKE_CFLAGS            += -pipe
QMAKE_CFLAGS_DEPS       += -M
QMAKE_CFLAGS_WARN_ON    += -Wall -W
QMAKE_CFLAGS_WARN_OFF   += -w
QMAKE_CFLAGS_RELEASE    +=
QMAKE_CFLAGS_DEBUG      += -g
QMAKE_CFLAGS_SHLIB      += -fPIC
QMAKE_CFLAGS_STATIC_LIB += -fPIC
QMAKE_CFLAGS_YACC       += -Wno-unused -Wno-parentheses
QMAKE_CFLAGS_HIDESYMS   += -fvisibility=hidden
QMAKE_CFLAGS_PRECOMPILE += -x c-header -c ${QMAKE_PCH_INPUT} -o ${QMAKE_PCH_OUTPUT}
QMAKE_CFLAGS_USE_PRECOMPILE += -include ${QMAKE_PCH_OUTPUT_BASE}
 
QMAKE_CXX               = g++
QMAKE_CXXFLAGS          += $$QMAKE_CFLAGS
QMAKE_CXXFLAGS_DEPS     += $$QMAKE_CFLAGS_DEPS
QMAKE_CXXFLAGS_WARN_ON  += $$QMAKE_CFLAGS_WARN_ON
QMAKE_CXXFLAGS_WARN_OFF += $$QMAKE_CFLAGS_WARN_OFF
QMAKE_CXXFLAGS_RELEASE  += $$QMAKE_CFLAGS_RELEASE
QMAKE_CXXFLAGS_DEBUG    += $$QMAKE_CFLAGS_DEBUG
QMAKE_CXXFLAGS_SHLIB    += $$QMAKE_CFLAGS_SHLIB
QMAKE_CXXFLAGS_STATIC_LIB += $$QMAKE_CFLAGS_STATIC_LIB
QMAKE_CXXFLAGS_YACC     += $$QMAKE_CFLAGS_YACC
QMAKE_CXXFLAGS_HIDESYMS += $$QMAKE_CFLAGS_HIDESYMS -fvisibility-inlines-hidden
QMAKE_CXXFLAGS_PRECOMPILE += -x c++-header -c ${QMAKE_PCH_INPUT} -o ${QMAKE_PCH_OUTPUT}
QMAKE_CXXFLAGS_USE_PRECOMPILE = $$QMAKE_CFLAGS_USE_PRECOMPILE

QMAKE_CC                = gcc
QMAKE_CFLAGS            += -pipe
QMAKE_CFLAGS_DEPS       += -M
QMAKE_CFLAGS_WARN_ON    += -Wall -W
QMAKE_CFLAGS_WARN_OFF   += -w
QMAKE_CFLAGS_RELEASE    +=
QMAKE_CFLAGS_DEBUG      += -g
QMAKE_CFLAGS_SHLIB      += -fPIC
QMAKE_CFLAGS_STATIC_LIB += -fPIC
QMAKE_CFLAGS_YACC       += -Wno-unused -Wno-parentheses
QMAKE_CFLAGS_HIDESYMS   += -fvisibility=hidden
QMAKE_CFLAGS_PRECOMPILE += -x c-header -c ${QMAKE_PCH_INPUT} -o ${QMAKE_PCH_OUTPUT}
QMAKE_CFLAGS_USE_PRECOMPILE += -include ${QMAKE_PCH_OUTPUT_BASE}

QMAKE_CXX               = g++
QMAKE_CXXFLAGS          += $$QMAKE_CFLAGS
QMAKE_CXXFLAGS_DEPS     += $$QMAKE_CFLAGS_DEPS
QMAKE_CXXFLAGS_WARN_ON  += $$QMAKE_CFLAGS_WARN_ON
QMAKE_CXXFLAGS_WARN_OFF += $$QMAKE_CFLAGS_WARN_OFF
QMAKE_CXXFLAGS_RELEASE  += $$QMAKE_CFLAGS_RELEASE
QMAKE_CXXFLAGS_DEBUG    += $$QMAKE_CFLAGS_DEBUG
QMAKE_CXXFLAGS_SHLIB    += $$QMAKE_CFLAGS_SHLIB
QMAKE_CXXFLAGS_STATIC_LIB += $$QMAKE_CFLAGS_STATIC_LIB
QMAKE_CXXFLAGS_YACC     += $$QMAKE_CFLAGS_YACC
QMAKE_CXXFLAGS_HIDESYMS += $$QMAKE_CFLAGS_HIDESYMS -fvisibility-inlines-hidden
QMAKE_CXXFLAGS_PRECOMPILE += -x c++-header -c ${QMAKE_PCH_INPUT} -o ${QMAKE_PCH_OUTPUT}
QMAKE_CXXFLAGS_USE_PRECOMPILE = $$QMAKE_CFLAGS_USE_PRECOMPILE

To copy to clipboard, switch view to plain text mode 

[wysota]

Looks fine to me. According to this -g should be in debug mode and not in release mode. My qmake gives me -g in release mode as well (it might be platform dependent, I'm using 'linux-g++' platform) but it's more important that it's there for debug. If -g is missing from your debug makefile, then obviously something had to remove it - maybe you are using some 3rd party addition that introduces such effect.

[pmitas]

I'm not saying -g should be in the release mode. I'm saying that at least -O2 should be in the release mode. Am I not right?

I just want to know if some optimization flags are SUPPOSED to be there or is it up to the distribution's maintainers. Or maybe it's supposed to be empty after all?

-g was missing from debug, but then I rebuilt qt-core and it popped back. Weird, but it happens, this problem is solved now. I just want to know about the release thing and I'll be gone