Include an assembly *.o file into a Qt C++ project - c++

Question

I have a Qt C++ Project.
System
Windows XP
QtCreator and QtSDK newest
C++
MinGW/gcc/g++
For performance reasons I need some functions to be done in assembly. My Project is mainly Qt and c++ but I need to link my C++ code to some assembly I wrote. I have an assembly *.o file but I can't access my assembly function from my c++ code. I complied the assembly calc.o file with nasm.
Simplified example.
PRO FILE
QT += core
QT -= gui
TARGET = Test_asm
CONFIG += console
CONFIG -= app_bundle
TEMPLATE = app
LIBS += C:/Users/David/Test_asm/calc.o
SOURCES += main.cpp
MAIN.CPP
#include <QtCore/QCoreApplication>
#include <QTextStream>
extern "C" int five();
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
QTextStream qout(stdout);
int f = five();
qout << "five: " << f << endl;
return a.exec();
}
ERROR
main.cpp:11: undefined reference to `five'
collect2: ld returned 1 exit status
TRY #1 - Karlphillip's way (Does not work on Windows)
Directory of C:\x
16/03/2012 03:09 PM <DIR> .
16/03/2012 03:09 PM <DIR> ..
16/03/2012 03:07 PM 82 calc.pro
16/03/2012 03:10 PM 178 calc.S
16/03/2012 03:10 PM 164 main.c
3 File(s) 424 bytes
2 Dir(s) 78,905,851,904 bytes free
C:\x>qmake
C:\x>make
'make' is not recognized as an internal or external command,
operable program or batch file.
C:\x>mingw32-make
mingw32-make -f Makefile.Debug
mingw32-make[1]: Entering directory `C:/x'
gcc -c -g -Wall -DUNICODE -DQT_LARGEFILE_SUPPORT -I"..\QtSDK\Desktop\Qt\4.7.3\mi
ngw\mkspecs\default" -o debug\main.o main.c
gcc -c -g -Wall -DUNICODE -DQT_LARGEFILE_SUPPORT -I"..\QtSDK\Desktop\Qt\4.7.3\mi
ngw\mkspecs\default" -o debug\calc.o calc.S
g++ -enable-stdcall-fixup -Wl,-enable-auto-import -Wl,-enable-runtime-pseudo-rel
oc -Wl,-subsystem,console -mthreads -Wl -o debug\calc.exe debug/main.o debug/cal
c.o
debug/main.o: In function `main':
C:\x/main.c:9: undefined reference to `helloasm'
collect2: ld returned 1 exit status
mingw32-make[1]: *** [debug\calc.exe] Error 1
mingw32-make[1]: Leaving directory `C:/x'
mingw32-make: *** [debug] Error 2

Answer 1

The best way that I found to work with assembly in QT Creator, it was to configure the .pro file. I added the nasm compiler to .pro file and some flags. You can change these flags if you need it. But with this configuration works well for me
example.pro
QMAKE_EXTRA_COMPILERS += nasm
NASMEXTRAFLAGS = -f elf64 -g -F dwarf
OTHER_FILES += $$NASM_SOURCES
nasm.output = ${QMAKE_FILE_BASE}.o
nasm.commands = nasm $$NASMEXTRAFLAGS -o ${QMAKE_FILE_BASE}.o ${QMAKE_FILE_NAME}
nasm.input = NASM_SOURCES
Finishing, you have to assign to NASM_SOURCES variable all the ASM files, in my case it was just one and it called arregloAsm.asm
NASM_SOURCES += arregloAsm.asm
I hope that all this works for you too!

Answer 2

Same thing as before:
calc.S:
.data
hello:
.string "Hello World\n"
.globl helloasm
helloasm:
movl $4, %eax
movl $1, %ebx
movl $hello,%ecx
movl $12,%edx
int $0x80
ret
main.c:
#include <stdio.h>
void helloasm();
int main()
{
printf("* Calling ASM function:\n");
helloasm();
printf("* Done!\n");
return 0;
}
calc.pro:
TEMPLATE = app
CONFIG += console
CONFIG -= qt
SOURCES += main.c \
calc.S
After putting all these files within the same directory, execute:
qmake
make
to verify the output:
$ ./calc
* Calling ASM function:
Hello World
* Done!

Answer 3

Why didn't you add calc.o to your sources?

Answer 4

I first did what was mentioned earlier:
testasm.pro
QT += core
QT -= gui
CONFIG += c++11
TARGET = testasm
CONFIG += console
CONFIG -= app_bundle
TEMPLATE = app
SOURCES += main.cpp
# The following define makes your compiler emit warnings if you use
# any feature of Qt which as been marked deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS
QMAKE_EXTRA_COMPILERS += nasm
NASMEXTRAFLAGS = -f elf64 -g -F dwarf
OTHER_FILES += $$NASM_SOURCES
nasm.output = ${QMAKE_FILE_BASE}.o
nasm.commands = nasm $$NASMEXTRAFLAGS -o ${QMAKE_FILE_BASE}.o ${QMAKE_FILE_NAME}
nasm.input = NASM_SOURCES
NASM_SOURCES += test.asm
main.cpp
#include <QCoreApplication>
extern "C" void test();
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
test();
return a.exec();
}
test.asm
global test
bits 64
section .text
test:
mov rax,0
ret
In the menu Build click build all and the application should be abel to run. It's a empty terminal in this example but on my system it works.
I was looking for a solution and thanks to this post, I finally have one.
Just remember to add
extern "C" void test();
to your main.cpp file. Notice "C" in the line because that was my biggest error.
(In case of language errors: I'm no native English speaker, if you like please correct the text)