OpenELEC: Bootstrap GCC with libatomic - gcc

I am trying to bootstrap GCC during OpenELEC compilation. I need to add libatomic for the target system so as to compile some packages.
When I try to add libatomic for the target system, I get a compilation error with:
/home/mathieu/tmp/OpenELEC.tv/build.OpenELEC-ci20.mips-8.0-devel/toolchain/mipsel-openelec-linux-gnu/bin/ld: cannot find crti.o: No such file or directory
/home/mathieu/tmp/OpenELEC.tv/build.OpenELEC-ci20.mips-8.0-devel/toolchain/mipsel-openelec-linux-gnu/bin/ld: cannot find -lc
/home/mathieu/tmp/OpenELEC.tv/build.OpenELEC-ci20.mips-8.0-devel/toolchain/mipsel-openelec-linux-gnu/bin/ld: cannot find crtn.o: No such file or directory
collect2: error: ld returned 1 exit status
Using the following package.mk file:
https://github.com/malaterre/OpenELEC.tv/blob/fd5a5558104ed38aee1c53bb6d31ba73e8eb6e57/packages/lang/gcc/package.mk
If that matter I am targetting a MIPS system, specifically the Creator CI20:
https://github.com/malaterre/OpenELEC.tv/blob/master/config/arch.mips
I am not clear about the OpenELEC build system, but it seems as if the host compiler and target compiler are build at the same time, while I would need to build binutils in between:
http://preshing.com/20141119/how-to-build-a-gcc-cross-compiler/

You might need to have a GCC built without libatomic to build one with libatomic. The intermediary compiler will serve to build your CRT (if you do not have it already) and libatomic, so that a second compiler can use these "prebuilt" things.

That was not hard at all. Basically one need to create first a minimal gcc (bootstrap) and then build the full one with libatomic:
https://github.com/malaterre/OpenELEC.tv/blob/70dbe25c1647f01eb83c108939c470437a2db259/packages/lang/gcc/package.mk

Related

Using gcc plugins with cross compiler, undefined symbol

I'm trying to see if it's possible to use a gcc plugin in an ARM cross compiler (arm-none-eabi-gcc). I'm running into compiler errors however, and am questioning whether what I'm trying to do is possible.
The plugin I'm trying to set up is: https://github.com/vanhauser-thc/AFLplusplus/tree/master/gcc_plugin
I'm compiling the plugin on x86-64 linux using the -m32 flag, since the cross compiler is a 32-bit application. However when I try to use the plugin in the cross compiler using -fplugin , I get an undefined symbol compiler error:
cc1plus: error: cannot load plugin ../afl-gcc-pass.so
../afl-gcc-pass.so: undefined symbol: _Z13build_int_cstP9tree_nodel
I looked through the plugin's symbols using nm and discovered that the majority of symbols are undefined, including ones like exit and random. I'm new to most of this and am unsure of what that really means. Some searching online suggested that it may have had something to do with incorrect library paths, but setting LIBRARY_PATH and LD_LIBRARY_PATH and rebuilding did not seem to help.
The gcc version set-ups I have tried:
1: x86: 5.4.0 , arm: 5.4.1 on ubuntu 16.04
2: x86: 5.2.0 , arm: 5.2.1 on CentOS 6.8
Is it possible to use a gcc plugin in a different gcc than it was compiled with or am I wasting my time?
Yes, it is possible to build a gcc plugin with a given compiler and then use the plugin in another compiler (including a cross-compiler), but you have to make sure you include the right header files when building the plugin.
Specifically, you have to include the plugin development header files of the target compiler, instead of those of the host compiler. The directory where plugin development files for your target compiler are located can be obtained with the following command:
$(TARGET_CC) -print-file-name=plugin
where $(TARGET_CC) is your target compiler. So a concise way to specify the relevant include directory in the compiler flags when building the plugin would be something like -I"$(shell $(TARGET_CC) -print-file-name=plugin)/include".
For the specific plugin you are trying to use (instrumentation for afl-fuzz), in order to build the plugin for your cross-compiler you could modify the Makefile in the gcc_plugin folder; more specifically, you could define a TARGET_CC variable containing the path to your cross-compiler, and then replace $(CC) with $(TARGET_CC) in the definition of PLUGIN_FLAGS, as in:
PLUGIN_FLAGS = -fPIC -fno-rtti -I"$(shell $(TARGET_CC) -print-file-name=plugin)/include"
You will also have to comment out the commands executed in the test_build Makefile target, because those commands would try to use the plugin with the native compiler and so would fail.
Then, you will be able to use the plugin with your cross-compiler, as in:
arm-none-eabi-gcc -fplugin=../afl-gcc-pass.so --specs=nosys.specs my_source_file.c

CMake: The C Compiler is not able to compile a simple test program

I am trying to cross-compile the Azure IoT SDK C for a Mips processor. Cross-compiling an older version of the same SDK using an older version of CMake (2.8.12.2) works just fine, so I doubt it's the code itself. I am guessing it's the Mips GCC compiler.
Error message:
CMake Error at /usr/share/cmake-3.10/Modules/CMakeTestCCompiler.cmake:52 (message):
The C compiler
"/usr/local/mipsisa32r2el/r23/bin/mipsisa32r2el-axis-linux-gnu-gcc"
is not able to compile a simple test program.
It fails with the following output:
Change Dir: /home/axis/azure-iot-sdk-c/cmake/iotsdk_linux/CMakeFiles/CMakeTmp
Run Build Command:"/usr/bin/make" "cmTC_2cc84/fast"
/usr/bin/make -f CMakeFiles/cmTC_2cc84.dir/build.make CMakeFiles/cmTC_2cc84.dir/build
make[1]: Entering directory '/home/axis/azure-iot-sdk-c/cmake/iotsdk_linux/CMakeFiles/CMakeTmp'
Building C object CMakeFiles/cmTC_2cc84.dir/testCCompiler.c.o
/usr/local/mipsisa32r2el/r23/bin/mipsisa32r2el-axis-linux-gnu-gcc --sysroot=/usr/local/mipsisa32r2el/r23 -o CMakeFiles/cmTC_2cc84.dir/testCCompiler.c.o -c /home/axis/azure-iot-sdk-c/cmake/iotsdk_linux/CMakeFiles/CMakeTmp/testCCompiler.c
Linking C executable cmTC_2cc84
/usr/bin/cmake -E cmake_link_script CMakeFiles/cmTC_2cc84.dir/link.txt --verbose=1
/usr/local/mipsisa32r2el/r23/bin/mipsisa32r2el-axis-linux-gnu-gcc --sysroot=/usr/local/mipsisa32r2el/r23 -rdynamic CMakeFiles/cmTC_2cc84.dir/testCCompiler.c.o -o cmTC_2cc84
/usr/local/mipsisa32r2el/r23/lib/gcc/mipsisa32r2el-axis-linux-gnu/4.7.2/../../../../mipsisa32r2el-axis-linux-gnu/bin/ld: this linker was not configured to use sysroots
collect2: error: ld returned 1 exit status
CMakeFiles/cmTC_2cc84.dir/build.make:97: recipe for target 'cmTC_2cc84' failed
make[1]: *** [cmTC_2cc84] Error 1
make[1]: Leaving directory '/home/axis/azure-iot-sdk-c/cmake/iotsdk_linux/CMakeFiles/CMakeTmp'
Makefile:126: recipe for target 'cmTC_2cc84/fast' failed
make: *** [cmTC_2cc84/fast] Error 2
Unfortunately, I am stuck with the Mips GCC compiler I have. Is there a way to disable this test-program check?
Solution was to add these to the toolchain-file:
SET (CMAKE_C_COMPILER_WORKS 1)
SET (CMAKE_CXX_COMPILER_WORKS 1)
CMake tries to compile an executable using "standard" (as per what CMake thinks is standard) compiler options and tries to run that executable, so to see if the compiler is working. The executable is simple like int main(int argc, char *argv[]) { return argc - 1; }.
You can't do that when cross-compiling. Because usually you can't link with a proper C standard library, you don't have printf, or _start or _exit or similar, passing arguments to main is implementation-defined, or you need a special linker script, or there's no emulator for your architecture, so can't run cross-compiled source on the host, etc... Simply: you usually can't run the cross-compiled executable on the host, and most of the time even the compilation is hard enough to do.
The common solution is to set before project():
set(CMAKE_TRY_COMPILE_TARGET_TYPE "STATIC_LIBRARY")
So that CMake will try to compile a static library not an executable, as explained in cmake docs CMAKE_TRY_COMPILE_TARGET_TYPE. This avoids running the linker and is intended for cross-compiling.
You can set CMAKE_C_COMPILER_WORKS and it will omit the check in CMakeTestCCompiler.cmake, but CMAKE_TRY_COMPILE_TARGET_TYPE is a more proper solution.
Well this problem is really annoying, i faced this issue for 2 day now I got solution.
Let me explain my issue first
When I delete NDK and Cmake from Sdk folder and Run my application then grable install NDK and Cmake again.
Only that time Application run and when try to run again i get this error The C Compiler is not able to compile a simple test program.
Before i was using ndkVersion "22.0.7026061" then change to thisndkVersion "21.1.6352462" and IT WORKED.
I think this is NDK problem and most of answer are outdated try this i hope this will HELP.
If using CMake GUI, you can add a boolean entry named
CMAKE_CXX_COMPILER_FORCED
then set it to True.
This will skip checking process for this build.
Ran into the same problem while re-compiling a project. Turned out that the compiler had been updated in the meantime.
After removing the build directory and creating it again, the compilation completed without errors.

g++ library search failure

I have a directory structure as below:
/
|
+--- /lib
| libsomething.a
| libsomething.so
|
+----/obj
anObjFile.o
When I run the following command from within the obj directory:
g++ -L../lib -lsomething anObjFile.o
I get undefined reference errors. Apparently gcc is failing to locate libsomething.a.
But now if I delete libsomething.so and then rerun the command, linking succeeds.
As per gcc documentation -lsomething should expand to libsomething.a. Then why is presence of libsomething.so causing the library search to fail? Also, how can I resolve this problem?
I'm on Linux Mint 12 with gcc version 4.6.1.
The .so file is a dynamic library, meaning it is used each time you run your program. In that case you need to tell your OS (Mint in this case) where that dynamic library is located so your prgramm can find it at run time.
The .a file is a static library, meaning functions needed from it will be copied into your prgramm while linking. So your prgramm can run without the library file.
If nothing else is said gcc will assume you want to use the dynamic lib. If it can find a .so file it will use it instead of a .a file. If you want to tell gcc to make your programm static (use the .a file) you can add -static to your gcc call.
However the reason why the linking fails when the dynamic library is used is not clear. How did you install/build the library?

Building GCC cross compiler (from "Linux" to "Windows")

I want to build "gcc cross-compiler" to compile "c/c++" applications on "Linux" environment but for "Windows" target.
I have made this so far:
Installed the necessary tools and packages for building GCC listed on "Prerequisites for GCC" page.
Downloaded required sources:
"gcc-core-4.4.1", "gcc-g++-4.4.1", "binutils-2.19.1", "w32api-3.13-mingw32", "mingwrt-3.16-mingw32"
Created this directory hierarchy:
"${HOME}/gcc/" - for final cross-compiler
"${HOME}/src/" - for sources
"${HOME}/src/build-binutils/i386-mingw32/" - for building binutils to "i386-mingw32" target
"${HOME}/src/build-gcc/i386-mingw32/" - for building gcc to "i386-mingw32" target
Builded binutils package:
cd "${HOME}/src/build-binutils/i386-mingw32/"
../../binutils-2.19.1/configure --prefix="${HOME}/gcc" --target=i386-mingw32 --disable-nls
make
make install
Copied "w32api" and "mingwrt" headers to the install directory:
cp -R "${HOME}/src/w32api-3.13-mingw32/include" "${HOME}/gcc/i386-mingw32"
cp -R "${HOME}/src/mingwrt-3.16-mingw32/include" "${HOME}/gcc/i386-mingw32"
And now when I am trying to build the "c (only) cross-compiler":
cd "${HOME}/src/build-gcc/i386-mingw32/"
../../gcc-4.4.1/configure --prefix="${HOME}/gcc" --target=i386-mingw32 --enable-languages=c --with-headers="${HOME}/gcc/i386-mingw32/include" --disable-nls
make<br>
it was building something about 4 minutes and then gives me these errors:
${HOME}/gcc/i386-mingw32/bin/ld: dllcrt2.o: No such file: No such file or directory
collect2: ld returned 1 exit status
make[2]: *** [libgcc_s.dll] Error 1
make[2]: Leaving directory `${HOME}/src/build-gcc/i386-mingw32/i386-mingw32/libgcc'
make[1]: *** [all-target-libgcc] Error 2
make[1]: Leaving directory `${HOME}/src/build-gcc/i386-mingw32'
make: *** [all] Error 2
From that error message I really don't know what to do now :-((( .
Does anybody know where is the problem?
Thanks.
That's actually OK: the way things go, you need to
build binutils
install headers
build the a partial C compiler: enough to create object files, but not enough to link
build the win32api and mingw runtime (which includes your missing dllcrt2.o)
build a complete C compiler (and other front-ends, such as C++, Fortran, Ada, whatever, if you want them)
You have successful performed step 3 above; it fails building libgcc (which is a GCC support library), but that means the C compiler core is functionnal (although it won't be able to link, it can still create valid object files). You can check that by looking at the gcc/xgcc file in your GCC build directory.
So, you need to go to the next step, not worrying about your current failure.
(To actuall install the partial C compiler, you should run make with the -k option, to have it do it best, even in the face of errors. For example, use make -k install.)
There are precompiled cross-compilers of MinGW-w64 available.
This allows to compile native 32- and 64-bit Windows binaries from Linux, a two minute tutorial is available at http://www.blogcompiler.com/2010/07/11/compile-for-windows-on-linux/
Just in case you don't want to spend a lot of time trying to build it yourself.
I grepped through the MinGW sources, and found that dllcrt2.o is something built off the mingwrt package. I assume you have to compile and install that, not just copy the headers?

Problem compiling gcc 4.4.0 on OpenSolaris 2009.6

I am attempting to compile gcc 4.4.0 on opensolaris 2009.6
Currently in the box (which is a AMD 64bit machine), I have the gcc 3.4.6 installed.
I unpacked the gcc 4.4.0 tarball.
I set the following env variables:
export CXX=/usr/local/bin/g++
export CC=/usr/local/bin/gcc
Then I ran "configure && make" and this is the error message that I got:
checking for i386-pc-solaris2.11-gcc... /export/home/me/wd/gcc/gcc-4.4.0/host-i386-pc-solaris2.11/gcc/xgcc -B/export/home/me/wd/gcc/gcc-4.4.0/host-i386-pc-solaris2.11/gcc/ -B/usr/local/i386-pc-solaris2.11/bin/ -B/usr/local/i386-pc-solaris2.11/lib/ -isystem /usr/local/i386-pc-solaris2.11/include -isystem /usr/local/i386-pc-solaris2.11/sys-include -m64
checking for suffix of object files... configure: error: in `/export/home/me/wd/gcc/gcc-4.4.0/i386-pc-solaris2.11/amd64/libgcc':
configure: error: cannot compute suffix of object files: cannot compile
See `config.log' for more details.
Anyone has any suggestion as to how to work around this error message?
/Edit:
Content of the config.log is posted here: link text
Normally the GCC build is bootstrapped, i.e. first it uses the system compiler to build GCC C compiler, and then it uses the freshly built compiler to recompile GCC once again (and then even once more time again). The configure line shows that it is not the system compiler but the already-built GCC compiler which is used for configure test there.
Since it fails, the problem is that the freshly-built GCC is somehow "stillborn" here. If config.log will not help you, I'd suggest to ask at gcc-help#gcc.gnu.org.
EDIT: Ah-ha, I think it is the assembler. You are using GNU assembler, but the unsupported options look like they were meant for Sun assembler. This should be solved by adding --with-gnu-as configure option (and then possibly having to specify its path explicitly with --with-as=/usr/gnu/bin/as)
You can also take a look at Solaris-specific GCC build instructions.
There's a readily available build for gcc4, which you can try updating. Its current version is 4.3.3. To get started, install pkg-get from OpenCSW and check out the build from the subversion repository:
svn co https://gar.svn.sourceforge.net/svnroot/gar/csw/mgar/pkg/gcc4/trunk/ gcc4
cd gcc4
gmake package

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