gcc and friends
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The document discusses the GNU C Compiler (gcc) which is an open source compiler for C and C++. It describes what gcc is, its internals including different stages like preprocessing, compilation and linking. It also covers how to use gcc via various flags, standard paths for headers and libraries, default compiler defines, and related tools like the assembler, linker and archiver.
gcc and friends
- 1. © 2010-15 SysPlay Workshops <workshop@sysplay.in> All Rights Reserved. gcc & Friends
- 2. 2© 2010-15 SysPlay Workshops <workshop@sysplay.in> All Rights Reserved. What to Expect? What is 'gcc'? Internals of 'gcc' How to use 'gcc'? Friends of 'gcc'
- 3. 3© 2010-15 SysPlay Workshops <workshop@sysplay.in> All Rights Reserved. What is 'gcc'? GNU C Compiler Open Source Compiler for C & C++ Along with standard headers & libraries Rather a collection of tools Corresponding to various compiler stages Various other compilers built using it Cross Compilers for different architectures
- 4. 4© 2010-15 SysPlay Workshops <workshop@sysplay.in> All Rights Reserved. 'gcc': Internals Decoded Pre Processor ICG (machine independent) ICG (machine dependent) Assembler (as) Linker (ld) .c .i IC(parse trees, ...) .S .o .exe gcc core gcc wrapper gcc -S gcc -c gcc gcc -E
- 5. 5© 2010-15 SysPlay Workshops <workshop@sysplay.in> All Rights Reserved. Using GNU C Compiler gcc file.c → Creates the executable a.out gcc file.c -o file gcc -E file.c → Pre-process only gcc -S file.c → Generate assembly code gcc -c file.c → Create object code gcc -I<hdrs_path> file.c gcc -L<libs_path> file.c -l<lib> gcc -D<define> file.c gcc -On file.c, n = 0, 1, 2, 3, s, fast, g gcc -M file.c gcc -MM file.c gcc -T <linker_script> file.c gcc -Wl,<linker_option> file.c ... (including many architecture specific flags)
- 6. 6© 2010-15 SysPlay Workshops <workshop@sysplay.in> All Rights Reserved. Default Compiler Defines Trick to find out (#gcc #define) gcc -E -dM -xc /dev/null | sort Also gcc -E -dM -xc++ /dev/null | sort gcc -E -dM -xc++ -std=c++0x /dev/null | sort
- 7. 7© 2010-15 SysPlay Workshops <workshop@sysplay.in> All Rights Reserved. Standard Paths Standard Headers Path: /usr/include/ Standard Libraries Path: /usr/lib/ Library Prefix: lib Standard Headers stdio.h, strings.h, math.h, ... Standard Libraries libc, libm, … Where is the code of printf?
- 8. 8© 2010-15 SysPlay Workshops <workshop@sysplay.in> All Rights Reserved. Friends of 'gcc' Preprocessor: cpp Assembler: as Linker: ld Name Lister: nm Disassembler: objdump Archiver: ar Print strings from files: strings ...
- 9. 9© 2010-15 SysPlay Workshops <workshop@sysplay.in> All Rights Reserved. What all have we learnt? gcc: GNU C Compiler Standard Headers & Libraries Collection of tools Usage of 'gcc' Friends of 'gcc'
- 10. 10© 2010-15 SysPlay Workshops <workshop@sysplay.in> All Rights Reserved. Any Queries?
- 11. 11© 2010-15 SysPlay Workshops <workshop@sysplay.in> All Rights Reserved. Advanced Topics Shared library vs Archive Linking, Library Function Call, ... Defining your own headers Creating a shared library Creating an archive