I am trying to build c file included by ndk under cygwin
In Android.mk, I add -I/usr/include to LOCAL_FLAGS like
LOCAL_FLAGS := -I/usr/include
And I have checked that openssl does under /usr/include
But when I run ndk-build under by project dir, it output
"fatal error: openssl/ssl.h: No such file or directory"
I think I have specified the include directory, but not solve this problem.
Is there any other way can I try?
You seem to have some gaps in your knowledge:
C code compiles to processor's native instruction set. Your desktop/build machine probably has a different architecture from your Android device(thus a different instruction set).
NDK doesn't just compile, it cross-compiles. It means that the NDK runs on the build machine, but the executable it produces cannot run on the build machine(different instruction sets).
All libraries on your desktop are in your desktop's processoer's instruction set. Thus, you cannot link any program build by the NDK using the desktop's libraries. This means:
No includes from '/usr/include/'
No libs from /lib, /usr/lib, /lib64 or /usr/lib64
No Cygwin packages under on Windows
What you need to do is build your own openssl using the NDK and use that to link against when you build your executable.
Please note that the answer is missing a lot of information (at least 3 Bachelor's level Computer Science courses worth of information).
Related
I have a prepared a minimal Cmake project containing one cpp file which represent the main and one cpp file which represent the shared library, that prints basically hello world.
https://github.com/courteous/wasmELF.git
The target is to compile this miniaml code with emscripten/clang only and produce
1) one WebAssembly (wasm) binary module version 0x1 (MVP)
2) one ELF 64-bit LSB
without clearing the cmake build directory and rebuilding it again.
Currently i can successfully produce them bought by running the commands
emconfigure cmake ../ -DCMAKE_BUILD_TYPE=WASM
make
and
cmake ../ -DCMAKE_BUILD_TYPE=Linux
make
However the problem is that in order to do that i need to compile the first one with Clang the to remove the build and then to do a second compilation with GCC. I would like Emscripten/Clang to produce them bought instead. I do not want to delete the build directory since the compilation times is taking too long. (Well not in this Project but imagine if the project was much larger)
What i see is that emscripten/clang selects always a target "wasm32-unknown-emscripten"
clang++ -target wasm32-unknown-emscripten
and if i understand that correctly the target should change
I do see that the project is producing LLVM IR bitcode since i have send the flag "flto"
i.e.
file TestSharedClass.cpp.o
TestSharedClass.cpp.o: LLVM IR bitcode
and in the CMakeLists.txt
set(CMAKE_CXX_FLAGS "-flto")
x86_64-unknown-linux-gnu is a supported target by emscripten/Clang
~/Projects/emscripten/emsdk/upstream/bin$ ./llc --version
LLVM (http://llvm.org/):
LLVM version 11.0.0git
Optimized build with assertions.
Default target: x86_64-unknown-linux-gnu
Host CPU: haswell
Registered Targets:
wasm32 - WebAssembly 32-bit
wasm64 - WebAssembly 64-bit
x86 - 32-bit X86: Pentium-Pro and above
x86-64 - 64-bit X86: EM64T and AMD64
In cmake i do have
SET(TARGET x86_64-unknown-linux-gnu)
however when i run
emconfigure cmake ../ -DCMAKE_BUILD_TYPE=Linux
make
i get mainTestFile.js and mainTestFile.wasm instead of ELF 64-bitcode.
what i am doing wrong here. How to tell clang to product once ELF and once wasm from the same code run without having to clear the build directory. This should be possible since clang is producing LLVM IR bitcode. Or do i understand that wrong?
https://github.com/emscripten-core/emscripten/issues/10361
OK that seems to not be possible i.e. the reply from the dev on github states that emcc or emmake can not be used with another target other then wasm32-unknown-emscripten.
I am working on Windows 7, using Eclipse DS-5, to cross-compile projects for Altera SoC (FPGA+ARM). The toolchain is supplied by Altera tools, and it looks as follows :
GCC C++ Compiler 4 [arm-linux-gnueabihf]
GCC C Compiler 4 [arm-linux-gnueabihf]
GCC Assembler 4 [arm-linux-gnueabihf]
GCC C Linker 4 [arm-linux-gnueabihf]
GCC C++ Linker 4 [arm-linux-gnueabihf]
GCC Archiver 4 [arm-linux-gnueabihf]
The Altera SoC board is running Angstrom Linux distribution on ARM.
I need to add some libraries (e.g. libcURL) and set the Eclipse project settings, to include the library in compilation.
MY UNDERSTANDING:
Libraries in general contain 2 components. The headers and the library definition files (in binary format). The compiler requires the header files, The linker is then linking the library files.
(If anything above is wrong, please correct me).
MY QUESTIONS:
1) In case the binary files are not supplied for ARM processor, do I need to use Altera tools to compile the library source code on my Windows 7 machine with ARM compiler ?
I believe to use the Altera supplied compiler terminal, to run ./configure, make
2) For such widely used libraries such as libcURL, there are pre-compiled binaries for different platforms. How do I know what the compiled library looks like ? What files are necessary for Eclipse to compile the whole project (please be specific : *.lib, *.a, *.h, ...)
SUMMARY:
I am perplexed by cross-compilation, I am not sure, which compiler is required, and which library files are required.
Most common error I have came across is :
cannot find -lcurl
Does that mean the compiler can see *.h files, but the Linker is not able to locate binary files ?
Finally, I did the following :
I have copied the library source files to my target platform (Altera De_nano_SoC ARM) and compiled the library there (Angstrom Linux, compiler arm-angstrom-linux-gnueabi). This requires setting configuration file in library folder, and running make and make install commands.
Once compiled, I copied the output files (headers *.h and static library files *.a OR shared library files *.so - depending on compilation configuration) to my host machine (Windows 7). Then I have added the files to my Eclipse DS-5 project.
The Eclipse requires the path of .../include folder with header files *.h and the .../lib folder including *.a or *.so files.
I'm trying to build a portable version of gcc 4.8.2. (for only C/C++ languages) The end result is have gcc installed into a specific application directory, eg, /opt/gcc-4.8.2 so that I can copy that directory from one computer to another (all computers are either intel corei5 or corei7, running recent Linux versions, eg, Ubuntu 12, Suse 10/11, Centos 5 & 6).
So far I'm able to build gcc ok, using --prefix to have the gcc outputs placed in a single directory (which can then be later copied to the other hosts). I configured & built gcc's dependencies (gmp, mpfr, mpc, isl) to have --disable-shared, so I can be sure that the final gcc, when copied to other hosts, won't complain about missing libraries or symbols.
I have a question with cloog. I configured gcc with --with-cloog (to pick up my locally built cloog, which I built along with the other gcc dependencies). However, what I don't know, is whether I also need to copy the cloog libraries and binary to each host I copy gcc to?
Also, how can I test gcc & cloog interaction? Is there a simple C file example and/or gcc command line that can be used to test whether gcc is successfully making use of cloog?
Additionally, are there any other considerations when trying to build a gcc which I then want to run on other hosts?
It depends if cloog is installed as a shared library libcloog-isl.so.* or as a static one libcloog.a ; use
ldd $(gcc-4.8 -print-file-name=cc1)
to find out. Of course you need to install all the shared libraries dependencies. If libcloog*so appears in the output of above ldd command, it is a shared library. Otherwise a static one.
You could set the LD_LIBRARY_PATH, or add the directory containing libcloog-isl.so.* (e.g. /usr/local/lib/ or /opt/lib/ etc...) to /etc/ld.so.conf (then run ldconfig)
I am not entirely sure your gcc build can run on every platform you mentioned. There might be libc* dependencies. See this. And perhaps also binutils dependencies (notably for gcc-4.8 -flto compilations).
To test gcc just compile with optimizations (e.g. gcc-4.8 -Wall -O3) some non-trivial file.
I am using Ubuntu 13.04 and installed mingw-w64 using apt-get install mingw-w64. I can compile and link a working 64-bit version of my program with the following command:
x86_64-w64-mingw32-g++ code.cpp -o app.exe
Which generates a 64-bit app.exe file.
What binary or command line flags do I use to generate a 32-bit version of app.exe?
That depends on which variant of toolchain you're currently using. Both DWARF and SEH variants (which come starting from GCC 4.8.0) are only single-target. You can see it yourself by inspecting the directory structure of their distributions, i.e. they contain only the libraries with either 64- or 32-bit addressing, but not both. On the other hand, plain old SJLJ distributions are indeed dual-target, and in order to build 32-bit target, just supply -m32 flag. If that doesn't work, then just build with i686-w64-mingw32-g++.
BONUS
By the way, the three corresponding dynamic-link libraries (DLLs) implementing each GCC exception model are
libgcc_s_dw2-1.dll (DWARF);
libgcc_s_seh-1.dll (SEH);
libgcc_s_sjlj-1.dll (SJLJ).
Hence, to find out what exception model does your current MinGW-w64 distribution exactly provide, you can either
inspect directory and file structure of MinGW-w64 installation in hope to locate one of those DLLs (typically in bin); or
build some real or test C++ code involving exception handling to force linkage with one of those DLLs and then see on which one of those DLLs does the built target depend (for example, can be seen with Dependency Walker on Windows); or
take brute force approach and compile some test code to assembly (instead of machine code) and look for presence of references like ___gxx_personality_v* (DWARF), ___gxx_personality_seh* (SEH), ___gxx_personality_sj* (SJLJ); see Obtaining current GCC exception model.
I currently compiled a set of source code in C in Linux and the output is a *.o file which is a object file. This supposedly does image compression. Now I want to use/test this in Android.
Is this possible? I have only tried NDK examples from the Android NDK developer side. Have not came across any reference on how this can be done.
Thanks In Advance,
Perumal
You don't run object code files (*.o). You would need to turn it into an executable. To do this, assuming you are using GCC you would run gcc file1.o file2.o -o executable which would convert a two file program with file1.o and file2.o into an executable called executable.
Object files (ending in .o) usually contain code that is incomplete. For example, if your program uses some library to print something on screen, to produce an executable, you must link your compiled code (the .o file) with the library, so that when the operating system loads the executable knows all the code that will be used. You do this linking with a linker (such as ld in Linux, or /system/bin/linker in Android). In your case, it's easier to let gcc call the linker for you, as Jalfor notes.
The answer is Yes. But you have to do some fair amount of work to see it running on Android.
1) If you are compiling on Linux, it means the object file or the final executable is being built for the x86 or AMD processor(Mostly). But mostly all the mobile devices have ARM processors running on their phones. So, though you have an executable you will not be able to execute it in ANdroid if it is not built for ARM Cpu. This is what android NDK does exactly.
2) So, we have to build the same code again for Android(ARM), for which we need a cross-compiler and the source code of the object files you are talking about.
3) If you have source code avilable, you can do 2 things again.
To include it in JNI folder, build the shared library and then do the
stuff of calling and all.
Build the code into an executable(Note you need to have main
inside the code) using the android NDK and then push the executable inside Android using
adb.
Now finally you can login and then check the result. In case anything is not clear, please do let me know. I wont mind explaining. Thanks..