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diff --git a/libstdc++-v3/docs/html/17_intro/porting.texi b/libstdc++-v3/docs/html/17_intro/porting.texi deleted file mode 100644 index 090bdf77155..00000000000 --- a/libstdc++-v3/docs/html/17_intro/porting.texi +++ /dev/null @@ -1,570 +0,0 @@ -\input texinfo - -@c --------------------------------------------------------------------- -@c Prologue -@c --------------------------------------------------------------------- - -@setfilename porting.info -@settitle Porting libstdc++-v3 -@setchapternewpage odd - -@copying -Copyright @copyright{} 2000, 2001, 2002, 2003, 2005 -Free Software Foundation, Inc. - -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 the -Invariant Sections being ``GNU General Public License'', the Front-Cover -texts being (a) (see below), and with the Back-Cover Texts being (b) -(see below). A copy of the license is included in the section entitled -``GNU Free Documentation License''. - -(a) The FSF's Front-Cover Text is: - - A GNU Manual - -(b) The FSF's Back-Cover Text is: - - You have freedom to copy and modify this GNU Manual, like GNU - software. Copies published by the Free Software Foundation raise - funds for GNU development. -@end copying - -@ifinfo -This file explains how to port libstdc++-v3 (the GNU C++ library) to -a new target. - -@insertcopying -@end ifinfo - -@c --------------------------------------------------------------------- -@c Titlepage -@c --------------------------------------------------------------------- - -@titlepage -@title Porting libstdc++-v3 -@author Mark Mitchell -@page -@vskip 0pt plus 1filll -@insertcopying -@end titlepage - -@c --------------------------------------------------------------------- -@c Top -@c --------------------------------------------------------------------- - -@node Top -@top Porting libstdc++-v3 - -This document explains how to port libstdc++-v3 (the GNU C++ library) to -a new target. - -In order to make the GNU C++ library (libstdc++-v3) work with a new -target, you must edit some configuration files and provide some new -header files. Unless this is done, libstdc++-v3 will use generic -settings which may not be correct for your target; even if they are -correct, they will likely be inefficient. - -Before you get started, make sure that you have a working C library on -your target. The C library need not precisely comply with any -particular standard, but should generally conform to the requirements -imposed by the ANSI/ISO standard. - -In addition, you should try to verify that the C++ compiler generally -works. It is difficult to test the C++ compiler without a working -library, but you should at least try some minimal test cases. - -(Note that what we think of as a ``target,'' the library refers to as -a ``host.'' The comment at the top of @file{configure.ac} explains why.) - -Here are the primary steps required to port the library: - -@menu -* Operating system:: Configuring for your operating system. -* CPU:: Configuring for your processor chip. -* Character types:: Implementing character classification. -* Thread safety:: Implementing atomic operations. -* Numeric limits:: Implementing numeric limits. -* Libtool:: Using libtool. -* GNU Free Documentation License:: How you can copy and share this manual. -@end menu - -@c --------------------------------------------------------------------- -@c Operating system -@c --------------------------------------------------------------------- - -@node Operating system -@chapter Operating system - -If you are porting to a new operating system (as opposed to a new chip -using an existing operating system), you will need to create a new -directory in the @file{config/os} hierarchy. For example, the IRIX -configuration files are all in @file{config/os/irix}. There is no set -way to organize the OS configuration directory. For example, -@file{config/os/solaris/solaris-2.6} and -@file{config/os/solaris/solaris-2.7} are used as configuration -directories for these two versions of Solaris. On the other hand, both -Solaris 2.7 and Solaris 2.8 use the @file{config/os/solaris/solaris-2.7} -directory. The important information is that there needs to be a -directory under @file{config/os} to store the files for your operating -system. - -You might have to change the @file{configure.host} file to ensure that -your new directory is activated. Look for the switch statement that sets -@code{os_include_dir}, and add a pattern to handle your operating system -if the default will not suffice. The switch statement switches on only -the OS portion of the standard target triplet; e.g., the @code{solaris2.8} -in @code{sparc-sun-solaris2.8}. If the new directory is named after the -OS portion of the triplet (the default), then nothing needs to be changed. - -The first file to create in this directory, should be called -@file{os_defines.h}. This file contains basic macro definitions -that are required to allow the C++ library to work with your C library. - -Several libstdc++-v3 source files unconditionally define the macro -@code{_POSIX_SOURCE}. On many systems, defining this macro causes -large portions of the C library header files to be eliminated -at preprocessing time. Therefore, you may have to @code{#undef} this -macro, or define other macros (like @code{_LARGEFILE_SOURCE} or -@code{__EXTENSIONS__}). You won't know what macros to define or -undefine at this point; you'll have to try compiling the library and -seeing what goes wrong. If you see errors about calling functions -that have not been declared, look in your C library headers to see if -the functions are declared there, and then figure out what macros you -need to define. You will need to add them to the -@code{CPLUSPLUS_CPP_SPEC} macro in the GCC configuration file for your -target. It will not work to simply define these macros in -@file{os_defines.h}. - -At this time, there are a few libstdc++-v3-specific macros which may be -defined: - -@code{_GLIBCXX_USE_C99_CHECK} may be defined to 1 to check C99 -function declarations (which are not covered by specialization below) -found in system headers against versions found in the library headers -derived from the standard. - -@code{_GLIBCXX_USE_C99_DYNAMIC} may be defined to an expression that -yields 0 if and only if the system headers are exposing proper support -for C99 functions (which are not covered by specialization below). If -defined, it must be 0 while bootstrapping the compiler/rebuilding the -library. - -@code{_GLIBCXX_USE_C99_LONG_LONG_CHECK} may be defined to 1 to check -the set of C99 long long function declarations found in system headers -against versions found in the library headers derived from the -standard. - -@code{_GLIBCXX_USE_C99_LONG_LONG_DYNAMIC} may be defined to an -expression that yields 0 if and only if the system headers are -exposing proper support for the set of C99 long long functions. If -defined, it must be 0 while bootstrapping the compiler/rebuilding the -library. - -@code{_GLIBCXX_USE_C99_FP_MACROS_DYNAMIC} may be defined to an -expression that yields 0 if and only if the system headers -are exposing proper support for the related set of macros. If defined, -it must be 0 while bootstrapping the compiler/rebuilding the library. - -@code{_GLIBCXX_USE_C99_FLOAT_TRANSCENDENTALS_CHECK} may be defined -to 1 to check the related set of function declarations found in system -headers against versions found in the library headers derived from -the standard. - -@code{_GLIBCXX_USE_C99_FLOAT_TRANSCENDENTALS_DYNAMIC} may be defined -to an expression that yields 0 if and only if the system headers -are exposing proper support for the related set of functions. If defined, -it must be 0 while bootstrapping the compiler/rebuilding the library. - -Finally, you should bracket the entire file in an include-guard, like -this: - -@example -#ifndef _GLIBCXX_OS_DEFINES -#define _GLIBCXX_OS_DEFINES -... -#endif -@end example - -We recommend copying an existing @file{os_defines.h} to use as a -starting point. - -@c --------------------------------------------------------------------- -@c CPU -@c --------------------------------------------------------------------- - -@node CPU -@chapter CPU - -If you are porting to a new chip (as opposed to a new operating system -running on an existing chip), you will need to create a new directory in the -@file{config/cpu} hierarchy. Much like the @ref{Operating system} setup, -there are no strict rules on how to organize the CPU configuration -directory, but careful naming choices will allow the configury to find your -setup files without explicit help. - -We recommend that for a target triplet @code{<CPU>-<vendor>-<OS>}, you -name your configuration directory @file{config/cpu/<CPU>}. If you do this, -the configury will find the directory by itself. Otherwise you will need to -edit the @file{configure.host} file and, in the switch statement that sets -@code{cpu_include_dir}, add a pattern to handle your chip. - -Note that some chip families share a single configuration directory, for -example, @code{alpha}, @code{alphaev5}, and @code{alphaev6} all use the -@file{config/cpu/alpha} directory, and there is an entry in the -@file{configure.host} switch statement to handle this. - -The @code{cpu_include_dir} sets default locations for the files controlling -@ref{Thread safety} and @ref{Numeric limits}, if the defaults are not -appropriate for your chip. - - -@c --------------------------------------------------------------------- -@c Character types -@c --------------------------------------------------------------------- - -@node Character types -@chapter Character types - -The library requires that you provide three header files to implement -character classification, analogous to that provided by the C libraries -@file{<ctype.h>} header. You can model these on the files provided in -@file{config/os/generic}. However, these files will almost -certainly need some modification. - -The first file to write is @file{ctype_base.h}. This file provides -some very basic information about character classification. The libstdc++-v3 -library assumes that your C library implements @file{<ctype.h>} by using -a table (indexed by character code) containing integers, where each of -these integers is a bit-mask indicating whether the character is -upper-case, lower-case, alphabetic, etc. The @file{ctype_base.h} -file gives the type of the integer, and the values of the various bit -masks. You will have to peer at your own @file{<ctype.h>} to figure out -how to define the values required by this file. - -The @file{ctype_base.h} header file does not need include guards. -It should contain a single @code{struct} definition called -@code{ctype_base}. This @code{struct} should contain two type -declarations, and one enumeration declaration, like this example, taken -from the IRIX configuration: - -@example -struct ctype_base -@{ - typedef unsigned int mask; - typedef int* __to_type; - - enum - @{ - space = _ISspace, - print = _ISprint, - cntrl = _IScntrl, - upper = _ISupper, - lower = _ISlower, - alpha = _ISalpha, - digit = _ISdigit, - punct = _ISpunct, - xdigit = _ISxdigit, - alnum = _ISalnum, - graph = _ISgraph - @}; -@}; -@end example - -@noindent -The @code{mask} type is the type of the elements in the table. If your -C library uses a table to map lower-case numbers to upper-case numbers, -and vice versa, you should define @code{__to_type} to be the type of the -elements in that table. If you don't mind taking a minor performance -penalty, or if your library doesn't implement @code{toupper} and -@code{tolower} in this way, you can pick any pointer-to-integer type, -but you must still define the type. - -The enumeration should give definitions for all the values in the above -example, using the values from your native @file{<ctype.h>}. They can -be given symbolically (as above), or numerically, if you prefer. You do -not have to include @file{<ctype.h>} in this header; it will always be -included before @file{ctype_base.h} is included. - -The next file to write is @file{ctype_noninline.h}, which also does -not require include guards. This file defines a few member functions -that will be included in @file{include/bits/locale_facets.h}. The first -function that must be written is the @code{ctype<char>::ctype} -constructor. Here is the IRIX example: - -@example -ctype<char>::ctype(const mask* __table = 0, bool __del = false, - size_t __refs = 0) - : _Ctype_nois<char>(__refs), _M_del(__table != 0 && __del), - _M_toupper(NULL), - _M_tolower(NULL), - _M_ctable(NULL), - _M_table(!__table - ? (const mask*) (__libc_attr._ctype_tbl->_class + 1) - : __table) - @{ @} -@end example - -@noindent -There are two parts of this that you might choose to alter. The first, -and most important, is the line involving @code{__libc_attr}. That is -IRIX system-dependent code that gets the base of the table mapping -character codes to attributes. You need to substitute code that obtains -the address of this table on your system. If you want to use your -operating system's tables to map upper-case letters to lower-case, and -vice versa, you should initialize @code{_M_toupper} and -@code{_M_tolower} with those tables, in similar fashion. - -Now, you have to write two functions to convert from upper-case to -lower-case, and vice versa. Here are the IRIX versions: - -@example -char -ctype<char>::do_toupper(char __c) const -@{ return _toupper(__c); @} - -char -ctype<char>::do_tolower(char __c) const -@{ return _tolower(__c); @} -@end example - -@noindent -Your C library provides equivalents to IRIX's @code{_toupper} and -@code{_tolower}. If you initialized @code{_M_toupper} and -@code{_M_tolower} above, then you could use those tables instead. - -Finally, you have to provide two utility functions that convert strings -of characters. The versions provided here will always work -- but you -could use specialized routines for greater performance if you have -machinery to do that on your system: - -@example -const char* -ctype<char>::do_toupper(char* __low, const char* __high) const -@{ - while (__low < __high) - @{ - *__low = do_toupper(*__low); - ++__low; - @} - return __high; -@} - -const char* -ctype<char>::do_tolower(char* __low, const char* __high) const -@{ - while (__low < __high) - @{ - *__low = do_tolower(*__low); - ++__low; - @} - return __high; -@} -@end example - -You must also provide the @file{ctype_inline.h} file, which -contains a few more functions. On most systems, you can just copy -@file{config/os/generic/ctype_inline.h} and use it on your system. - -In detail, the functions provided test characters for particular -properties; they are analogous to the functions like @code{isalpha} and -@code{islower} provided by the C library. - -The first function is implemented like this on IRIX: - -@example -bool -ctype<char>:: -is(mask __m, char __c) const throw() -@{ return (_M_table)[(unsigned char)(__c)] & __m; @} -@end example - -@noindent -The @code{_M_table} is the table passed in above, in the constructor. -This is the table that contains the bitmasks for each character. The -implementation here should work on all systems. - -The next function is: - -@example -const char* -ctype<char>:: -is(const char* __low, const char* __high, mask* __vec) const throw() -@{ - while (__low < __high) - *__vec++ = (_M_table)[(unsigned char)(*__low++)]; - return __high; -@} -@end example - -@noindent -This function is similar; it copies the masks for all the characters -from @code{__low} up until @code{__high} into the vector given by -@code{__vec}. - -The last two functions again are entirely generic: - -@example -const char* -ctype<char>:: -scan_is(mask __m, const char* __low, const char* __high) const throw() -@{ - while (__low < __high && !this->is(__m, *__low)) - ++__low; - return __low; -@} - -const char* -ctype<char>:: -scan_not(mask __m, const char* __low, const char* __high) const throw() -@{ - while (__low < __high && this->is(__m, *__low)) - ++__low; - return __low; -@} -@end example - -@c --------------------------------------------------------------------- -@c Thread safety -@c --------------------------------------------------------------------- - -@node Thread safety -@chapter Thread safety - -The C++ library string functionality requires a couple of atomic -operations to provide thread-safety. If you don't take any special -action, the library will use stub versions of these functions that are -not thread-safe. They will work fine, unless your applications are -multi-threaded. - -If you want to provide custom, safe, versions of these functions, there -are two distinct approaches. One is to provide a version for your CPU, -using assembly language constructs. The other is to use the -thread-safety primitives in your operating system. In either case, you -make a file called @file{atomicity.h}, and the variable -@code{ATOMICITYH} must point to this file. - -If you are using the assembly-language approach, put this code in -@file{config/cpu/<chip>/atomicity.h}, where chip is the name of -your processor (@pxref{CPU}). No additional changes are necessary to -locate the file in this case; @code{ATOMICITYH} will be set by default. - -If you are using the operating system thread-safety primitives approach, -you can also put this code in the same CPU directory, in which case no more -work is needed to locate the file. For examples of this approach, -see the @file{atomicity.h} file for IRIX or IA64. - -Alternatively, if the primitives are more closely related to the OS -than they are to the CPU, you can put the @file{atomicity.h} file in -the @ref{Operating system} directory instead. In this case, you must -edit @file{configure.host}, and in the switch statement that handles -operating systems, override the @code{ATOMICITYH} variable to point to -the appropriate @code{os_include_dir}. For examples of this approach, -see the @file{atomicity.h} file for AIX. - -With those bits out of the way, you have to actually write -@file{atomicity.h} itself. This file should be wrapped in an -include guard named @code{_GLIBCXX_ATOMICITY_H}. It should define one -type, and two functions. - -The type is @code{_Atomic_word}. Here is the version used on IRIX: - -@example -typedef long _Atomic_word; -@end example - -@noindent -This type must be a signed integral type supporting atomic operations. -If you're using the OS approach, use the same type used by your system's -primitives. Otherwise, use the type for which your CPU provides atomic -primitives. - -Then, you must provide two functions. The bodies of these functions -must be equivalent to those provided here, but using atomic operations: - -@example -static inline _Atomic_word -__attribute__ ((__unused__)) -__exchange_and_add (_Atomic_word* __mem, int __val) -@{ - _Atomic_word __result = *__mem; - *__mem += __val; - return __result; -@} - -static inline void -__attribute__ ((__unused__)) -__atomic_add (_Atomic_word* __mem, int __val) -@{ - *__mem += __val; -@} -@end example - -@c --------------------------------------------------------------------- -@c Numeric limits -@c --------------------------------------------------------------------- - -@node Numeric limits -@chapter Numeric limits - -The C++ library requires information about the fundamental data types, -such as the minimum and maximum representable values of each type. -You can define each of these values individually, but it is usually -easiest just to indicate how many bits are used in each of the data -types and let the library do the rest. For information about the -macros to define, see the top of @file{include/bits/std_limits.h}. - -If you need to define any macros, you can do so in @file{os_defines.h}. -However, if all operating systems for your CPU are likely to use the -same values, you can provide a CPU-specific file instead so that you -do not have to provide the same definitions for each operating system. -To take that approach, create a new file called @file{cpu_limits.h} in -your CPU configuration directory (@pxref{CPU}). - -@c --------------------------------------------------------------------- -@c Libtool -@c --------------------------------------------------------------------- - -@node Libtool -@chapter Libtool - -The C++ library is compiled, archived and linked with libtool. -Explaining the full workings of libtool is beyond the scope of this -document, but there are a few, particular bits that are necessary for -porting. - -Some parts of the libstdc++-v3 library are compiled with the libtool -@code{--tags CXX} option (the C++ definitions for libtool). Therefore, -@file{ltcf-cxx.sh} in the top-level directory needs to have the correct -logic to compile and archive objects equivalent to the C version of libtool, -@file{ltcf-c.sh}. Some libtool targets have definitions for C but not -for C++, or C++ definitions which have not been kept up to date. - -The C++ run-time library contains initialization code that needs to be -run as the library is loaded. Often, that requires linking in special -object files when the C++ library is built as a shared library, or -taking other system-specific actions. - -The libstdc++-v3 library is linked with the C version of libtool, even -though it is a C++ library. Therefore, the C version of libtool needs to -ensure that the run-time library initializers are run. The usual way to -do this is to build the library using @code{gcc -shared}. - -If you need to change how the library is linked, look at -@file{ltcf-c.sh} in the top-level directory. Find the switch statement -that sets @code{archive_cmds}. Here, adjust the setting for your -operating system. - -@c --------------------------------------------------------------------- -@c GFDL -@c --------------------------------------------------------------------- - -@include fdl.texi - -@c --------------------------------------------------------------------- -@c Epilogue -@c --------------------------------------------------------------------- - -@contents -@bye |