From my understanding of cmake, the tool takes care of file path and command lines length to avoid reaching windows limitation of 8191 characters.
However I'm cross compiling with arm_none_eabi on windows and cmake doesn't generate a makefile using response files or any other workaround for the path length. Thus the link step fails.
Here is the generated makefile line that causes issue
XXXXX_EXTERNAL_OBJECTS =
XXXX_OBJECTS = \
"file1.c.obj" \
"file2.c.obj" \
"file3.c.obj" \
"fileXX.c.obj" \
C:/YYYY/GNU_Tools_ARM_Embedded/6-2016-q4-major/bin/arm-none-eabi-gcc.exe -mcpu=cortex-m4 -mthumb -DSTM32L4__xx -mfloat-abi=softfp -DXXXX -O0 -g -Wfatal-errors -Wall -Wno-unused-function -std=c99 -fdata-sections -ffunction-sections -mcpu=cortex-m4 -march=armv7e-m -O0 -g --specs=nano.specs -mthumb -Wl,--gc-sections -nostartfiles -Wl,-Map=$#.map -TC:SSSSSSSSS/STM32L4__RGTx_FLASH.ld $(XXXX_OBJECTS) $(XXXXX_EXTERNAL_OBJECTS) -o outHexFile_XXXX -LC:/YYYYYYYYYYYYYYYY/arm-nano-eabi/lib
The final line length is about 23000 characters (far over 8191).
Why is Cmake not generating a makefile usable by windows ?
Is this only because I am cross-compiling ?
What can I do to avoid this issue ?
EDIT
Generator is GNU Makefiles
CMake Version 3.7.2
EDIT 2
this may be automatically handled in future versions
submited bug
Turning my comment into an answer
I had the same problem with the command line length and could solve it with adding the following "use response file" settings to my toolchain file:
SET(CMAKE_C_USE_RESPONSE_FILE_FOR_OBJECTS 1)
SET(CMAKE_CXX_USE_RESPONSE_FILE_FOR_OBJECTS 1)
SET(CMAKE_C_RESPONSE_FILE_LINK_FLAG "#")
SET(CMAKE_CXX_RESPONSE_FILE_LINK_FLAG "#")
And if you would have had used ninja you would need an additional:
SET(CMAKE_NINJA_FORCE_RESPONSE_FILE 1 CACHE INTERNAL "")
Related
I have a simple project with a simple configure.ac script:
AC_INIT(...)
AM_INIT_AUTOMAKE([-Wall -Werror foreign])
AC_PROG_CC
AC_CONFIG_HEADERS([config.h])
AC_CONFIG_FILES(...)
AC_OUTPUT
using GNU Autoconf version 2.69 (OpenSUSE Linux with gcc 9.2.1), but gcc is being called with no warning flags:
gcc -DHAVE_CONFIG_H -I. -I.. -g -O2 -MT aprog.o -MD -MP -MF .deps/aprog.Tpo -c -o aprog.o aprog.c
mv ...
gcc -g -O2 -o aprog aprog.o -lgmp
In particular, I found -Wformat not working. Shouldn't -Wall include -Wformat? And shouldn't all warnings appear on the make line? If I run gcc line directly with -Wformat the warning shows in compile but it doesn't when I run autoconf, configure and make.
What I'm doing wrong?
The -Wall flag in the AM_INIT_AUTOMAKE(...) invocation refers to warnings from automake and related tools like aclocal, not to compiler warnings. You will see these warnings when you are running autoreconf.
Note that while you can also add -Werror to AM_INIT_AUTOMAKE(...) to make your autoreconf run fail on warnings, many common macros (like those shipped with gettext or libtool) will still use deprecated macros which generates a warning, so -Werror means you cannot use this standard set of tools, so -Werror is not very useful in many cases.
If you want to add compiler options, there are a third party macros (e.g. AX_CHECK_COMPILE_FLAG) which test whether the compiler recognizes a given compile option and you can then add them to some variable and use that in places. That is a different stackoverflow question, though.
I"m using CMake 3.17 and the GNU ARM toolchain and I'm trying to migrate a build from Eclipse to CMake. Part of the Eclipse build specifies multiple linker script files to use at link time so I set up my CMakeLists.txt file like this:
target_link_options(${application_name} PRIVATE
-mcpu=cortex-m4
-mthumb
-mfloat-abi=hard
-mfpu=fpv4-sp-d16
-fmessage-length=0
-fsigned-char
-ffunction-sections
-fdata-sections
-flto
-Wall
-Xlinker --gc-sections
-Wl,-Map,${map_file}
-T ${CMAKE_SOURCE_DIR}/ldscripts/libs.ld
-T ${CMAKE_SOURCE_DIR}/ldscripts/mem.ld
-T ${CMAKE_SOURCE_DIR}/ldscripts/sections.ld
)
But when I run make the -T option gets swallowed for the second and third files. Here's what I get when running make VERBOSE=1 after successful compilation of all sources. The linker command line followed by a warning about missing -T options:
Linking CXX executable StartupSequence.elf
/D/gcc-arm-none-eabi-9-2019-q4/bin/arm-none-eabi-g++.exe --specs=nano.specs --specs=nosys.specs -g -Og -mcpu=cortex-m4 -mthumb -mfloat-abi=hard -mfpu=fpv4-sp-d16 -fmessage-length=0 -fsigned-char -ffunction-sections -fdata-sections -flto -Wall -Xlinker --gc-sections -Wl,-Map,StartupSequence.map -T C:/svn/startup_sequence/ldscripts/libs.ld C:/svn/startup_sequence/ldscripts/mem.ld C:/svn/startup_sequence/ldscripts/sections.ld #CMakeFiles/StartupSequence.dir/objects1.rsp -o StartupSequence.elf ../Drivers/CMSIS/DSP/Lib/libarm_cortexM4lf_math.a ../Middlewares/Third_Party/mbedTLS/library/libmbedcrypto.a
d:/gcc-arm-none-eabi-9-2019-q4/bin/../lib/gcc/arm-none-eabi/9.2.1/../../../../arm-none-eabi/bin/ld.exe: warning: C:/svn/startup_sequence/ldscripts/sections.ld contains output sections; did you forget -T?
Why does the -T not get sent to the command line properly for the last two files?
I've tried separating the link script specification into three separate calls to target_link_options and enclosing each script specification in double quotes but it seems to have no effect.
By default, CMake de-duplicates compile and link options. That is, multiple -T options are combined into the single one.
CMake doesn't know which options are actually bonded with the further arguments, but provides a SHELL: mechanism for define such options:
target_link_options(${application_name} PRIVATE
"SHELL:-T ${CMAKE_SOURCE_DIR}/ldscripts/libs.ld"
"SHELL:-T ${CMAKE_SOURCE_DIR}/ldscripts/mem.ld"
"SHELL:-T ${CMAKE_SOURCE_DIR}/ldscripts/sections.ld"
)
This mechanism is described in the documentation for target_link_options command.
The same mechanism works for compiler options passed to target_compile_options, see that question and my answer for it.
Because -T is interpreted as an single option. Glue -T with the path instead. Try:
-T${CMAKE_SOURCE_DIR}/ldscripts/libs.ld
-T${CMAKE_SOURCE_DIR}/ldscripts/mem.ld
-T${CMAKE_SOURCE_DIR}/ldscripts/sections.ld
I am porting a project from VxWorks 5.x to 7 and the new version of the "gcc" (4.8.1) compiler is not displaying the "#warning" statements within my C code.
The following are the flags I am using and none of them appear to inhibit the warning messages:
-march=corei7 -mpopcnt -maes -mpclmul -mavx -mfsgsbase -mrdrnd -mf16c -mavx2 -mmovbe -mfma -mbmi -mbmi2 -mrdseed -madx -mprfchw -nostdlib -fno-builtin -fno-defer-pop -m64 -fno-omit-frame-pointer -mcmodel=$(CM) -mno-red-zone -fno-implicit-fp -ansi -fno-zero-initialized-in-bss -O2 -w -g -w
I even added '-Wall' and that had NO affect. If I replaced on of the '#warning's with '#error', the build fails, indicating that the code IS getting compiled.
Can anybody assist?
From the manual:
-w Inhibit all warning messages.
You have two of those in your command line.
I installed OCaml via OPAM, and by default it uses gcc as the command to compile .c files. For instance, if I run ocamlopt -verbose file.c, I obtain:
+ gcc -Wall -D_FILE_OFFSET_BITS=64 -D_REENTRANT -g
-fno-omit-frame-pointer -c -I'/home/user/.opam/4.02.1+fp/lib/ocaml' 'test.c'
I'd like to change the GCC binary that is used by OCaml, for instance to replace it with gcc-5.1 or /opt/my-gcc/bin/gcc.
Is it possible to do so without reconfiguring and recompiling OCaml? I suppose I could add a gcc alias to a directory in the PATH, but I'd prefer a cleaner solution if there is one.
To check if gcc was not chosen based on a textual configuration file (that I could easily change), I searched for occurrences of gcc in my /home/user/.opam/4.02.1+fp directory, but the only occurrence in a non-binary file that I found was in lib/ocaml/Makefile.config, and changing it does nothing for the already-compiled binary.
ocamlopt uses gcc for three things. First, for compiling .c files that appear on the command line of ocamlopt. Second, for assembling the .s files that it generates internally when compiling an OCaml source file. Third, for linking the object files together at the end.
For the first and third, you can supply a different compiler with the -cc flag.
For the second, you need to rebuild the OCaml compiler.
Update
Here's what I see on OS X when compiling a C and an OCaml module with the -verbose flag:
$ ocamlopt -verbose -cc gcc -o m m.ml c.c 2>&1 | grep -v warning
+ clang -arch x86_64 -c -o 'm.o' \
'/var/folders/w4/1tgxn_s936b148fdgb8l9xv80000gn/T/camlasm461f1b.s' \
+ gcc -c -I'/usr/local/lib/ocaml' 'c.c'
+ clang -arch x86_64 -c -o \
'/var/folders/w4/1tgxn_s936b148fdgb8l9xv80000gn/T/camlstartup695941.o' \
'/var/folders/w4/1tgxn_s936b148fdgb8l9xv80000gn/T/camlstartupb6b001.s'
+ gcc -o 'm' '-L/usr/local/lib/ocaml' \
'/var/folders/w4/1tgxn_s936b148fdgb8l9xv80000gn/T/camlstartup695941.o' \
'/usr/local/lib/ocaml/std_exit.o' 'm.o' \
'/usr/local/lib/ocaml/stdlib.a' 'c.o' \
'/usr/local/lib/ocaml/libasmrun.a'
So, the compiler given by the -cc option is used to do the compilation of the .c file and the final linking. To change the handling of the .s files you need to rebuild the compiler. I'm going to update my answer above.
I was using soekris box for my embedded linux assignment where i had to compile my c file using -war and -werror . can any body help me how can i use this two minimal flag while compiling?
Just open the terminal and enter something like this:
gcc -x c -c -Wall -Werror ./path/to/our/fency/c/file.c ?
I added a few more flags:
`-x c` - tells the compiler that it's a C code.
`-c` - tells the compiler just to compile, no linking.
And ones You asked for:
`-Wall` - turns all warning reporting.
`-Werror` - tells to make all warnings into errors.
You can read some more about gcc flags by checking gcc --help or in documentation.
Add them to your Makefile as CFLAGS.
CFLAGS = -Wall -Werror