Compiler (1A) Young Won Lim 6/8/14

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1 Compiler (1A)

2 Copyright (c) Young W. Lim. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License". Please send corrections (or suggestions) to youngwlim@hotmail.com. This document was produced by using OpenOffice.

3 Compiling gcc -Wall hello.c -o hello /usr/lib/libm.a gcc main.o hello_fn.o -o hello gcc -Wall calc.c /usr/lib/libm.a -o calc gcc -Wall calc.c -lm -o calc gcc -Wall -lm calc.c -o calc (incorrect order) gcc -Wall -I/opt/gdbm-1.8.3/include dbmain.c -lgdbm gcc -Wall -I/opt/gdbm-1.8.3/include -L/opt/gdbm-1.8.3/lib dbmain.c -lgdbm Compiler 3

4 gcc /usr/lib/gcc-lib/... cpp0 cc1 cc1obj cc1plus f771 jc1 collect2 Compiler 4

5 gcc 1. Program Files c++, c++filt, cc (link to gcc), cc1, cc1plus, collect2, cpp, cpp0, g++, gcc, gccbug, gcov and tradcpp0 2. Descriptions 2.1 cc, cc1, cc1plus, gcc These are the C compiler. 2.2 c++, cc1plus, g++ These are the C++ compiler, the equivalent of cc and gcc etc. 2.3 c++filt The c++filt program does the inverse mapping: it decodes (demangles) lowlevel names into user-level names so that the linker can keep these overloaded functions from clashing. 2.4 collect2 collect2 assists with the compilation of constructors. The C++ language provides function overloading, which means that it is possible to write many functions with the same name (providing each takes parameters of different types). All C++ function names are encoded into a low-level assembly label (this process is known as mangling). Compiler 5

6 gcc 2.5 cpp, cpp0 cpp pre-processes a source file, such as including the contents of header files into the source file. Simply add a line, such as #include <filename>, to your source file. The preprocessor will insert the contents of the included file into the source file. 2.6 gccbug gccbug is a shell script which is used to simplify the creation of bug reports. 2.7 gcov gcov analyzes programs to help create more efficient, faster running code through optimization. A2.8 tradcpp0 No description is currently available. Compiler 6

7 Compiling $ C_INCLUDE_PATH=/opt/gdbm-1.8.3/include $ export C_INCLUDE_PATH $ CPLUS_INCLUDE_PATH=/opt/gdbm-1.8.3/include $ export CPLUS_INCLUDE_PATH $ LIBRARY_PATH=/opt/gdbm-1.8.3/lib $ export LIBRARY_PATH $ C_INCLUDE_PATH=.:/opt/gdbm-1.8.3/include:/net/include $ LIBRARY_PATH=.:/opt/gdbm-1.8.3/lib:/net/lib $ gcc -I. -I/opt/gdbm-1.8.3/include -I/net/include -L. -L/opt/gdbm-1.8.3/lib -L/net/lib... Compiler 7

8 ELF -save-temps -save-temps=cwd Store the usual "temporary" intermediate files permanently; place them in the current directory and name them based on the source file. Thus, compiling foo.c with -c -save-temps produces files foo.i and foo.s, as well as foo.o. This creates a preprocessed foo.i output file even though the compiler now normally uses an integrated preprocessor. When used in combination with the -x command-line option, -save-temps is sensible enough to avoid over writing an input source file with the same extension as an intermediate file. The corresponding intermediate file may be obtained by renaming the source file before using -save-temps. If you invoke GCC in parallel, compiling several different source files that share a common base name in different subdirectories or the same source file compiled for multiple output destinations, it is likely that the different parallel compilers will interfere with each other, and overwrite the temporary files. For instance: Compiler 8

9 -save-temps -g Produce debugging information in the operating system's native format (stabs, COFF, XCOFF, or DWARF 2). GDB can work with this debugging information. On most systems that use stabs format, -g enables use of extra debugging information that only GDB can use; this extra information makes debugging work better in GDB but probably makes other debuggers crash or refuse to read the program. If you want to control for certain whether to generate the extra information, use -gstabs+, -gstabs, -gxcoff+, -gxcoff, or -gvms (see below). GCC allows you to use -g with -O. The shortcuts taken by optimized code may occasionally produce surprising results: some variables you declared may not exist at all; flow of control may briefly move where you did not expect it; some statements may not be executed because they compute constant results or their values are already at hand; some statements may execute in different places because they have been moved out of loops. Nevertheless it proves possible to debug optimized output. This makes it reasonable to use the optimizer for programs that might have bugs. Compiler 9

10 -save-temps gcc -save-temps -o outdir1/foo.o indir1/foo.c& gcc -save-temps -o outdir2/foo.o indir2/foo.c& may result in foo.i and foo.o being written to simultaneously by both compilers. -save-temps=obj Store the usual "temporary" intermediate files permanently. If the -o option is used, the temporary files are based on the object file. If the -o option is not used, the -save-temps=obj switch behaves like -save-temps. For example: gcc -save-temps=obj -c foo.c gcc -save-temps=obj -c bar.c -o dir/xbar.o gcc -save-temps=obj foobar.c -o dir2/yfoobar creates foo.i, foo.s, dir/xbar.i, dir/xbar.s, dir2/yfoobar.i, dir2/yfoobar.s, and dir2/yfoobar.o. Compiler 10

11 -g gcc -save-temps -o outdir1/foo.o indir1/foo.c& gcc -save-temps -o outdir2/foo.o indir2/foo.c& may result in foo.i and foo.o being written to simultaneously by both compilers. -save-temps=obj Store the usual "temporary" intermediate files permanently. If the -o option is used, the temporary files are based on the object file. If the -o option is not used, the -save-temps=obj switch behaves like -save-temps. For example: gcc -save-temps=obj -c foo.c gcc -save-temps=obj -c bar.c -o dir/xbar.o gcc -save-temps=obj foobar.c -o dir2/yfoobar creates foo.i, foo.s, dir/xbar.i, dir/xbar.s, dir2/yfoobar.i, dir2/yfoobar.s, and dir2/yfoobar.o. Compiler 11

12 -g -v Verbose mode. Print out GNU CPP's version number at the beginning of execution, and report the final form of the include path. Compiler 12

13 GCC Options gcc -W -Wall -O2 -o t t.c -E -S -c -v --save-temps Compiler 13

14 CC1 Options -ansi -std -traditional -fno -asm -W -Wall -O0 -O1 -O2 -O3 -Os Compiler 14

15 Debug Options -g -pg Compiler 15

16 Collect2, ld Options -L -l -shared -static -nostdlib -nostartfiles -Wl -s -x -n -r -e -M -oformat Compiler 16

17 ELF gcc -da t.c as -V -Qy -o t.o t.s Compiler 17

18 Static Library Compiler 18

19 Dynamic Shared Library Compiler 19

20 References [1] An Introduction to GCC, B. Gough, [2] Unix, Linux Programming Indispensable Utilities, CW Paik

Arguments of C++ Applications g++ options Libraries

Arguments of C++ Applications g++ options Libraries Shahram Rahatlou University of Rome La Sapienza Corso di Programmazione++ Roma, 23 May 2006 Options of g++ $ man g++ GCC(1) GNU GCC(1) NAME gcc - GNU