GAST: Gcc Automatically Save Temps Copyright (C) 2009-2010 Tadashi Koike (T.K) ** Please overlook my weak English. ** Table of contents ============ 1. Purpose of this project 2. Product contents 3. Environment to be needed 4. Install & setup 5. How to use 6. Environment variables to control 'gast' 7. Use case 8. Weak point of this tool ============ 1. Purpose of this project A purpose of this project (GAST) is to support getting preprocessed source codes (.i file) automatically which corresponds directly to a generated object file (.o file), If you want. 2. Product contents This project provides three tools (=bash scripts) at present. - gast : wrapper script for gcc This script must be executed by alias name which is same as real compiler ('gcc','cc', etc...). In build process, these alias names must be found before real compile in command path search, so those directory path must be set PATH environment at least before of real compiler's command path. When this script is executed (by alias name), do below processes: 1) Analisys of command line arguments. If arguments are for compiling C/C++ language source file, this script executes real compiler (same as alias name) with these arguments addittionaly '-save-temps' option. If arguments are not for compiling C/C++ language source file, this script executes real compiler (same as alias name) only with these arguments and then exit. 2) After compiling C/C++ language source file, preprocessed source file (.i extension, called 'temporary file') is there. If directory for preserving temporary file is specified (by environment variable), temporary file is moved to that directory. 3) Delete temporary file for assembler (.s extension). Before using this script, you have to set some environment variables to control 'gast' action. For more information, see "6. Environment variables to control 'gast'". [ NOTICE ] If C/C++ source file compiling is done under 'make' process, you perhaps need support by 'gast_make' script (below). - gast_make : wrapper script for make command This script must be executed by alias name which is same as real make-utility ('make','gmake', etc...). In build process, these alias names must be found before real make utility in command path search, so those directory path must be set PATH environment at least before of real make-utility command path. When this script is executed (by alias name), do below processes: 1) Analisys of command line arguments. If arguments has '-j ' or '--jobs=' option, this script force number of jobs to set 1 and execute real make-utility (same as alias name) with these arguments. If arguments does not have '-j ' or '--jobs=', this script executes real make-utility (same as alias name) with given arguments and additionally '-j1' option. [ NOTICE ] gcc (version 4.4 or under) creates temporary files in current/working directory. If GNU make utility runs simultaneously by specified '-j|--jobs' option, and one C/C++ source file is compiled simultaneously for respective purpose, build process maybe failed because temporary files are in conflict. So this script support you to set simultaneous job number to 1 by force. - gast_rpmbuild : wrapper script for rpmbuild command This script must be executed by alias name 'rpmbuild'. (for Red Hat Enterprise Linux, CentOS, Fedora, ...) This script is substitution for rpmbuild command to set environment variable for 'gast' automatically. Additional option '--save-temps-dir' is abailable to specify directory name for preserving temporary files. In build process, these alias names must be found before real rpmbuild in command path search, so those directory path must be set PATH environment at least before of real rpmbuild command path. When this script is executed (by alias name), do below processes: 1) Analisys of command line arguments. If arguments contains '--save-temps-dir' option, followed argument is recognized as directory name for preserving temporary files and set to environment variable for controling 'gast'. 2) Set some other environment variables (contains PATH) for preserving temporary files. 3) Executes real rpmbuild command with arguments given to this script, except for '--save-temps-dir' and followed directory name argument. 3. Environment to be needed To use these scripts, some utilities are needed below: ・GNU gcc compiler ・GNU Make utility ・bash (version 3.0 or later are desirable) and strongly recommended utility are below: ・perl * If perl is not vailable, bash script processes text-filtering all by itself, but processing speed became more slowly. 4. Install & setup [ Install ] This product is provided by tar+gzip archive format. Extracting that archive file means just installing. If you extract archive file, a directory is created and utility scripts is in there. for example) extracting archive file on /home/foo. archive file supposed 'gast-0.1.2.tar.gz' $ cd /home/foo $ tar -xvzf /tmp/gast-0.1.2.tar.gz gast-0.1.2/ gast-0.1.2/gast gast-0.1.2/gast_make gast-0.1.2/gast_rpmbuild gast-0.1.2/README.ja_JP.UTF-8 [ setup ] 1) Change a working directory to an extracted directory. $ cd /home/foo/gast-0.1.2 2) If you need, please add/modify your compiler/make utility name to 'gast.aliases'. $ vi gast.aliases 3) Execute 'gast_symlink' script. this script creates symbolic link file for each wrapper script. Symbolic link filename are selected from 'gast.aliases'. $ ./gast_symlink If you want to add new symbolic link, you have to modify 'gast.aliases' file again, and re-execute 'gast_symlink'. for exampe) $ ./gast_symlink If you want to select script to create symbolic link, please specify script name. for exampe) $ ./gast_symlink gast 4) If you want to delete symbolic link, execute 'gast_symlink' with '-u' option. All symbolic link files are deleted. $ ./gast_symlink -u If you want to select script to delete symbolic link, please specify script name. for exampe) $ ./gast_symlink -u gast_make [ NOTICE ] - gast, gast_make, gast_rpmbuild must be in same directory. Don't move these scripts in several directories separately. - gast, gast_make, gast_rpmbuild must not be in same directory as real commands/utilities. (gcc,cc,make,gmake,rpmbuild,...) I recommended using these tools as in extracted directory. - Of course, build process spends more time. perhaps spends 1.2 to 3 times as long as usually. 5. How to use ======================================================================= Seen A) to build RPM package from SRPM by using rpmbuild command. You can start using this tools. Please execute rpmbuild script (= aliases name of gast_rpmbuild) directory. Example) get temporary files of kernel build on CentOS +------------------------------------------------------------------ |$ /home/foo/gast-0.1.2/rpmbuild --save-temps-dir /home/foo/tmp \ | --rebuild /tmp/kernel-2.6.18-92.1.10.el5.src.rpm +------------------------------------------------------------------ Option arguments for real rpmbuild are all available . additiona option '--save-temps-dir' are available to specifiy preserving temporary files. (in above example, /home/foo/tmp) If you need, you define GAST_CONTENT_WITHOUT_H, GAST_CONTENT_UNIQUE, and GAST_SAVE_ASM environment variables. +------------------------------------------------------------------ |$ export GAST_CONTENT_WITHOUT_H= |$ export GAST_CONTENT_UNIQUE= |$ export GAST_SAVE_ASM= +------------------------------------------------------------------ see "6. Environment variables to control 'gast'". [ !! NOTICE !! ] If you build a big package (like a linux kernel), I strongly recommend defining GAST_CONTENT_WITHOUT_H environment variable or specifying a big-size filesystem to preserve temporary files. Otherwise, filesystem to preserve temporary files might be full !! ======================================================================= Seen B) to build a configure/make/make install/ style product. You need these steps: 1. Set environment variables to control 'gast'. 2. Set the directory path of this scripts to the top of the value of PATH environment variable, and continue build process. Example) build of Apache HTTPD 2.2 (httpd-2.2.11.tar.gz) +------------------------------------------------------------------ |$ cd /tmp |$ tar -xvzf httpd-2.2.11.tar.gz |$ cd /tmp/httpd-2.2.11 |$ ./configure --prefix=/home/foo/local | : | : | $ # before doing 'make', we set environment variable for 'gast' | $ export GAST_ENABLE= | $ export GAST_SOURCE_DIR=/tmp | $ export GAST_SAVE_DIR=/home/foo/tmp | $ export GAST_CONTENT_WITHOUT_H= | $ export GAST_CONTENT_UNIQUE= | $ export GAST_SAVE_ASM= | $ | $ # do build | $ PATH=/home/foo/gast-0.1.2:${PATH} make | ： | ： | $ make install +------------------------------------------------------------------ see "6. Environment variables to control 'gast'". [ NOTICE ] I recommend that changing PATH environment variable must be temporary. So in above example, setting PATH environment variable is specified at the top of build command line. If you finished, delete environment variables. +------------------------------------------------------------------ |$ unset GAST_ENABLE GAST_SOURCE_DIR GAST_SAVE_DIR |$ unset GAST_CONTENT_WITHOUT_H GAST_CONTENT_UNIQUE |$ unset GAST_SAVE_ASM +------------------------------------------------------------------ ======================================================================= Seen C) only compile one C/C++ source file. Same as configure/make/make install/ style build process. Below is an another example: +------------------------------------------------------------------ |$ GAST_ENABLE= GAST_SOURCE_DIR=/tmp GAST_SAVE_DIR=/home/foo/tmp \ |> GAST_CONTENT_WITHOUT_H= GAST_SAVE_ASM= \ |> PATH=/home/foo/gast-0.1.2:$PATH \ |> gcc test.c +------------------------------------------------------------------ ... confusing. 6. Environment variables to control 'gast' If you want to get temporary (=preprocessed) file using 'gast', you must specify some environment variables to control 'gast' before compileing/building your target source/product. GAST_ENABLE When this environment variable is defined (however excludes its value is "no"), gast works to generate compiler's temporary file (.i file) automatically, and preserve it. When this environment variable is not defined, gast behaves itself like just same as an real compiler. GAST_SAVE_DIR= When this environment variable is defined and its value can be recognized a directory name, a genrerated temporary file (.i file) by compiler is moved to this directory. When this directory does not exist, gast attempt to create this directory. [ CAUTION!! ] I strongly recommend to define GAST_SAVE_DIR environment variable. If you don't define GAST_SAVE_DIR environment variable, temporary files (.i file) are created in current/working directory, but filename of these temporary files are changed as below: Example) test.i ---> test.0.i Why do I change filename? Because there is a case that the C/C++ source file is compiled any number of times with different compile options. When temporary files are created in 'current/working' directory and compiled any number of times, older temporary files are overwritten, so I assume that case and prevent to be overwritten , I rename original temporary filename with adding '.0'. GAST_SOURCE_DIR= When this environment variable is defined and its value can be recognized a directory name, gast tries to obtain a relative path-name from a source file path-name by removing a directory name which this environment means. And that relative path-name applies under the GAST_SAVE_DIR directory to moved a temporary file (.i file). When this environment variable is not defined or the value does not match a header of source file path-name, gast obtain a relative path-name by removing "/" from a top of source file path-name. [ NOTICE ] When this environment variable is not defined and gast is executed under a build process by 'rpmbuild' command, gast tries to define GAST_SOURCE_DIR automatically with a value of RPM_BUILD_DIR. GAST_CONTENT_WITHOUT_H When this environment variable is defined (however excludes its value is "no"), created temporary file (.i file) is modified. Most of all the contents from header files are removed. [NOTICE] Only a track of including header file is left. GAST_CONTENT_UNIQUE When this environment variable is not defined, If C/C++ source file is compiled any number of times with different compile options, gast preserve each temporary files by adding number. When this environment variable is defined (however excludes its value is "no"), If compile options are different but content of current temporary file is same as one of the preserved files, gast does not preserve current temporary file. GAST_SAVE_ASM When this environment variable is defined (however excludes its value is "no"), generated assembler file (.s file) is also preserved. 7. Use case 1) Assistance for researching source code (to understand macro expanding). 2) To gather error messages not from C/C++ source file but from temporary files. 3) ... 8. Weak point of this tool If compiler is executed by absolute path in build process, gast script is not able to work, so at that case, we cannot get temporary files. ===