1 Design document for the unified scheme data
2 ===========================================
4 How are things connected?
5 -------------------------
7 The unified scheme takes all its data from the build.info files seen
8 throughout the source tree. These files hold the minimum information
9 needed to build end product files from diverse sources. See the
10 section on build.info files below.
12 From the information in build.info files, Configure builds up an
13 information database as a hash table called %unified_info, which is
14 stored in configdata.pm, found at the top of the build tree (which may
15 or may not be the same as the source tree).
17 Configurations/common.tmpl uses the data from %unified_info to
18 generate the rules for building end product files as well as
19 intermediary files with the help of a few functions found in the
20 build-file templates. See the section on build-file templates further
21 down for more information.
26 As mentioned earlier, build.info files are meant to hold the minimum
27 information needed to build output files, and therefore only (with a
28 few possible exceptions [1]) have information about end products (such
29 as scripts, library files and programs) and source files (such as C
30 files, C header files, assembler files, etc). Intermediate files such
31 as object files are rarely directly referred to in build.info files (and
32 when they are, it's always with the file name extension .o), they are
33 inferred by Configure. By the same rule of minimalism, end product
34 file name extensions (such as .so, .a, .exe, etc) are never mentioned
35 in build.info. Their file name extensions will be inferred by the
36 build-file templates, adapted for the platform they are meant for (see
37 sections on %unified_info and build-file templates further down).
39 The variables PROGRAMS, LIBS, ENGINES and SCRIPTS are used to declare
40 end products. There are variants for them with '_NO_INST' as suffix
41 (PROGRAM_NO_INST etc) to specify end products that shouldn't get
44 The variables SOURCE, DEPEND, INCLUDE and ORDINALS are indexed by a
45 produced file, and their values are the source used to produce that
46 particular produced file, extra dependencies, include directories
47 needed, and ordinal files (explained further below.
49 All their values in all the build.info throughout the source tree are
50 collected together and form a set of programs, libraries, engines and
51 scripts to be produced, source files, dependencies, etc etc etc.
53 Let's have a pretend example, a very limited contraption of OpenSSL,
54 composed of the program 'apps/openssl', the libraries 'libssl' and
55 'libcrypto', an engine 'engines/ossltest' and their sources and
60 ORDINALS[libcrypto]=crypto
62 INCLUDE[libcrypto]=include
63 INCLUDE[libssl]=include
64 DEPEND[libssl]=libcrypto
66 This is the top directory build.info file, and it tells us that two
67 libraries are to be built, there are some ordinals to be used to
68 declare what symbols in those libraries are seen as public, the
69 include directory 'include/' shall be used throughout when building
70 anything that will end up in each library, and that the library
71 'libssl' depend on the library 'libcrypto' to function properly.
75 SOURCE[openssl]=openssl.c
76 INCLUDE[openssl]=.. ../include
77 DEPEND[openssl]=../libssl
79 This is the build.info file in 'apps/', one may notice that all file
80 paths mentioned are relative to the directory the build.info file is
81 located in. This one tells us that there's a program to be built
82 called 'apps/openssl' (the file name extension will depend on the
83 platform and is therefore not mentioned in the build.info file). It's
84 built from one source file, 'apps/openssl.c', and building it requires
85 the use of '.' and 'include' include directories (both are declared
86 from the point of view of the 'apps/' directory), and that the program
87 depends on the library 'libssl' to function properly.
91 SOURCE[../libcrypto]=aes.c evp.c cversion.c
92 DEPEND[cversion.o]=buildinf.h
94 GENERATE[buildinf.h]=../util/mkbuildinf.pl "$(CC) $(CFLAGS)" "$(PLATFORM)"
95 DEPEND[buildinf.h]=../Makefile
96 DEPEND[../util/mkbuildinf.pl]=../util/Foo.pm
98 This is the build.info file in 'crypto', and it tells us a little more
99 about what's needed to produce 'libcrypto'. LIBS is used again to
100 declare that 'libcrypto' is to be produced. This declaration is
101 really unnecessary as it's already mentioned in the top build.info
102 file, but can make the info file easier to understand. This is to
103 show that duplicate information isn't an issue.
105 This build.info file informs us that 'libcrypto' is built from a few
106 source files, 'crypto/aes.c', 'crypto/evp.c' and 'crypto/cversion.c'.
107 It also shows us that building the object file inferred from
108 'crypto/cversion.c' depends on 'crypto/buildinf.h'. Finally, it
109 also shows the possibility to declare how some files are generated
110 using some script, in this case a perl script, and how such scripts
111 can be declared to depend on other files, in this case a perl module.
113 Two things are worth an extra note:
115 'DEPEND[cversion.o]' mentions an object file. DEPEND indexes is the
116 only location where it's valid to mention them
118 Lines in 'BEGINRAW'..'ENDRAW' sections must always mention files as
119 seen from the top directory, no exception.
123 SOURCE[../libssl]=tls.c
125 This is the build.info file in 'ssl/', and it tells us that the
126 library 'libssl' is built from the source file 'ssl/tls.c'.
130 SOURCE[dasync]=e_dasync.c
131 DEPEND[dasync]=../libcrypto
132 INCLUDE[dasync]=../include
134 ENGINES_NO_INST=ossltest
135 SOURCE[ossltest]=e_ossltest.c
136 DEPEND[ossltest]=../libcrypto
137 INCLUDE[ossltest]=../include
139 This is the build.info file in 'engines/', telling us that two engines
140 called 'engines/dasync' and 'engines/ossltest' shall be built, that
141 dasync's source is 'engines/e_dasync.c' and ossltest's source is
142 'engines/e_ossltest.c' and that the include directory 'include/' may
143 be used when building anything that will be part of these engines.
144 Also, both engines depend on the library 'libcrypto' to function
145 properly. Finally, only dasync is being installed, as ossltest is
146 only for internal testing.
148 When Configure digests these build.info files, the accumulated
149 information comes down to this:
151 LIBS=libcrypto libssl
152 ORDINALS[libcrypto]=crypto
153 SOURCE[libcrypto]=crypto/aes.c crypto/evp.c crypto/cversion.c
154 DEPEND[crypto/cversion.o]=crypto/buildinf.h
155 INCLUDE[libcrypto]=include
157 SOURCE[libssl]=ssl/tls.c
158 INCLUDE[libssl]=include
159 DEPEND[libssl]=libcrypto
161 PROGRAMS=apps/openssl
162 SOURCE[apps/openssl]=apps/openssl.c
163 INCLUDE[apps/openssl]=. include
164 DEPEND[apps/openssl]=libssl
166 ENGINES=engines/dasync
167 SOURCE[engines/dasync]=engines/e_dasync.c
168 DEPEND[engines/dasync]=libcrypto
169 INCLUDE[engines/dasync]=include
171 ENGINES_NO_INST=engines/ossltest
172 SOURCE[engines/ossltest]=engines/e_ossltest.c
173 DEPEND[engines/ossltest]=libcrypto
174 INCLUDE[engines/ossltest]=include
176 GENERATE[crypto/buildinf.h]=util/mkbuildinf.pl "$(CC) $(CFLAGS)" "$(PLATFORM)"
177 DEPEND[crypto/buildinf.h]=Makefile
178 DEPEND[util/mkbuildinf.pl]=util/Foo.pm
181 A few notes worth mentioning:
183 LIBS may be used to declare routine libraries only.
185 PROGRAMS may be used to declare programs only.
187 ENGINES may be used to declare engines only.
189 The indexes for SOURCE and ORDINALS must only be end product files,
190 such as libraries, programs or engines. The values of SOURCE
191 variables must only be source files (possibly generated)
193 INCLUDE and DEPEND shows a relationship between different files
194 (usually produced files) or between files and directories, such as a
195 program depending on a library, or between an object file and some
198 When Configure processes the build.info files, it will take it as
199 truth without question, and will therefore perform very few checks.
200 If the build tree is separate from the source tree, it will assume
201 that all built files and up in the build directory and that all source
202 files are to be found in the source tree, if they can be found there.
203 Configure will assume that source files that can't be found in the
204 source tree (such as 'crypto/bildinf.h' in the example above) are
205 generated and will be found in the build tree.
208 The %unified_info database
209 --------------------------
211 The information in all the build.info get digested by Configure and
212 collected into the %unified_info database, divided into the following
215 depends => a hash table containing 'file' => [ 'dependency' ... ]
216 pairs. These are directly inferred from the DEPEND
217 variables in build.info files.
219 engines => a list of engines. These are directly inferred from
220 the ENGINES variable in build.info files.
222 generate => a hash table containing 'file' => [ 'generator' ... ]
223 pairs. These are directly inferred from the GENERATE
224 variables in build.info files.
226 includes => a hash table containing 'file' => [ 'include' ... ]
227 pairs. These are directly inferred from the INCLUDE
228 variables in build.info files.
230 install => a hash table containing 'type' => [ 'file' ... ] pairs.
231 The types are 'programs', 'libraries', 'engines' and
232 'scripts', and the array of files list the files of
233 that type that should be installed.
235 libraries => a list of libraries. These are directly inferred from
236 the LIBS variable in build.info files.
238 ordinals => a hash table containing 'file' => [ 'word', 'ordfile' ]
239 pairs. 'file' and 'word' are directly inferred from
240 the ORDINALS variables in build.info files, while the
241 file 'ofile' comes from internal knowledge in
244 programs => a list of programs. These are directly inferred from
245 the PROGRAMS variable in build.info files.
247 rawlines => a list of build-file lines. These are a direct copy of
248 the BEGINRAW..ENDRAW lines in build.info files. Note:
249 only the BEGINRAW..ENDRAW section for the current
250 platform are copied, the rest are ignored.
252 scripts => a list of scripts. There are directly inferred from
253 the SCRIPTS variable in build.info files.
255 sources => a hash table containing 'file' => [ 'sourcefile' ... ]
256 pairs. These are indirectly inferred from the SOURCE
257 variables in build.info files. Object files are
258 mentioned in this hash table, with source files from
259 SOURCE variables, and AS source files for programs and
263 a hash table just like 'sources', but only as source
264 files (object files) for building shared libraries.
266 As an example, here is how the build.info files example from the
267 section above would be digested into a %unified_info table:
269 our %unified_info = (
276 "crypto/buildinf.h" =>
280 "crypto/cversion.o" =>
284 "engines/ossltest" =>
292 "util/mkbuildinf.pl" =>
304 "crypto/buildinf.h" =>
306 "util/mkbuildinf.pl",
319 "engines/ossltest" =>
331 "util/mkbuildinf.pl" =>
362 "util/libcrypto.num",
391 "crypto/cversion.o" =>
399 "engines/e_ossltest.o" =>
401 "engines/e_ossltest.c",
403 "engines/ossltest" =>
405 "engines/e_ossltest.o",
424 As can be seen, everything in %unified_info is fairly simple suggest
425 of information. Still, it tells us that to build all programs, we
426 must build 'apps/openssl', and to build the latter, we will need to
427 build all its sources ('apps/openssl.o' in this case) and all the
428 other things it depends on (such as 'libssl'). All those dependencies
429 need to be built as well, using the same logic, so to build 'libssl',
430 we need to build 'ssl/tls.o' as well as 'libcrypto', and to build the
437 Build-file templates are essentially build-files (such as Makefile on
438 Unix) with perl code fragments mixed in. Those perl code fragment
439 will generate all the configuration dependent data, including all the
440 rules needed to build end product files and intermediary files alike.
441 At a minimum, there must be a perl code fragment that defines a set of
442 functions that are used to generates specific build-file rules, to
443 build static libraries from object files, to build shared libraries
444 from static libraries, to programs from object files and libraries,
447 generatesrc - function that produces build file lines to generate
448 a source file from some input.
450 It's called like this:
452 generatesrc(src => "PATH/TO/tobegenerated",
453 generator => [ "generatingfile", ... ]
454 generator_incs => [ "INCL/PATH", ... ]
455 generator_deps => [ "dep1", ... ]
456 incs => [ "INCL/PATH", ... ],
457 deps => [ "dep1", ... ],
458 intent => one of "libs", "dso", "bin" );
460 'src' has the name of the file to be generated.
461 'generator' is the command or part of command to
462 generate the file, of which the first item is
463 expected to be the file to generate from.
464 generatesrc() is expected to analyse and figure out
465 exactly how to apply that file and how to capture
466 the result. 'generator_incs' and 'generator_deps'
467 are include directories and files that the generator
468 file itself depends on. 'incs' and 'deps' are
469 include directories and files that are used if $(CC)
470 is used as an intermediary step when generating the
471 end product (the file indicated by 'src'). 'intent'
472 indicates what the generated file is going to be
475 src2obj - function that produces build file lines to build an
476 object file from source files and associated data.
478 It's called like this:
480 src2obj(obj => "PATH/TO/objectfile",
481 srcs => [ "PATH/TO/sourcefile", ... ],
482 deps => [ "dep1", ... ],
483 incs => [ "INCL/PATH", ... ]
484 intent => one of "lib", "dso", "bin" );
486 'obj' has the intended object file *without*
487 extension, src2obj() is expected to add that.
488 'srcs' has the list of source files to build the
489 object file, with the first item being the source
490 file that directly corresponds to the object file.
491 'deps' is a list of explicit dependencies. 'incs'
492 is a list of include file directories. Finally,
493 'intent' indicates what this object file is going
496 obj2lib - function that produces build file lines to build a
497 static library file ("libfoo.a" in Unix terms) from
502 obj2lib(lib => "PATH/TO/libfile",
503 objs => [ "PATH/TO/objectfile", ... ]);
505 'lib' has the intended library file name *without*
506 extension, obj2lib is expected to add that. 'objs'
507 has the list of object files (also *without*
508 extension) to build this library.
510 libobj2shlib - function that produces build file lines to build a
511 shareable object library file ("libfoo.so" in Unix
512 terms) from the corresponding static library file
517 libobj2shlib(shlib => "PATH/TO/shlibfile",
518 lib => "PATH/TO/libfile",
519 objs => [ "PATH/TO/objectfile", ... ],
520 deps => [ "PATH/TO/otherlibfile", ... ],
521 ordinals => [ "word", "/PATH/TO/ordfile" ]);
523 'lib' has the intended library file name *without*
524 extension, libobj2shlib is expected to add that.
525 'shlib' has the corresponding shared library name
526 *without* extension. 'deps' has the list of other
527 libraries (also *without* extension) this library
528 needs to be linked with. 'objs' has the list of
529 object files (also *without* extension) to build
530 this library. 'ordinals' MAY be present, and when
531 it is, its value is an array where the word is
532 "crypto" or "ssl" and the file is one of the ordinal
533 files util/libcrypto.num or util/libssl.num in the
536 This function has a choice; it can use the
537 corresponding static library as input to make the
538 shared library, or the list of object files.
540 obj2dynlib - function that produces build file lines to build a
541 dynamically loadable library file ("libfoo.so" on
542 Unix) from object files.
546 obj2dynlib(lib => "PATH/TO/libfile",
547 objs => [ "PATH/TO/objectfile", ... ],
548 deps => [ "PATH/TO/otherlibfile",
551 This is almost the same as libobj2shlib, but the
552 intent is to build a shareable library that can be
553 loaded in runtime (a "plugin"...). The differences
554 are subtle, one of the most visible ones is that the
555 resulting shareable library is produced from object
558 obj2bin - function that produces build file lines to build an
559 executable file from object files.
563 obj2bin(bin => "PATH/TO/binfile",
564 objs => [ "PATH/TO/objectfile", ... ],
565 deps => [ "PATH/TO/libfile", ... ]);
567 'bin' has the intended executable file name
568 *without* extension, obj2bin is expected to add
569 that. 'objs' has the list of object files (also
570 *without* extension) to build this library. 'deps'
571 has the list of library files (also *without*
572 extension) that the programs needs to be linked
575 in2script - function that produces build file lines to build a
576 script file from some input.
580 in2script(script => "PATH/TO/scriptfile",
581 sources => [ "PATH/TO/infile", ... ]);
583 'script' has the intended script file name.
584 'sources' has the list of source files to build the
585 resulting script from.
587 Along with the build-file templates is the driving engine
588 Configurations/common.tmpl, which looks through all the information in
589 %unified_info and generates all the rulesets to build libraries,
590 programs and all intermediate files, using the rule generating
591 functions defined in the build-file template.
593 As an example with the smaller build.info set we've seen as an
594 example, producing the rules to build 'libcrypto' would result in the
597 # Note: libobj2shlib will only be called if shared libraries are
599 # Note 2: libobj2shlib gets both the name of the static library
600 # and the names of all the object files that go into it. It's up
601 # to the implementation to decide which to use as input.
602 # Note 3: common.tmpl peals off the ".o" extension from all object
603 # files, as the platform at hand may have a different one.
604 libobj2shlib(shlib => "libcrypto",
606 objs => [ "crypto/aes", "crypto/evp", "crypto/cversion" ],
608 ordinals => [ "crypto", "util/libcrypto.num" ]);
610 obj2lib(lib => "libcrypto"
611 objs => [ "crypto/aes", "crypto/evp", "crypto/cversion" ]);
613 src2obj(obj => "crypto/aes"
614 srcs => [ "crypto/aes.c" ],
616 incs => [ "include" ],
619 src2obj(obj => "crypto/evp"
620 srcs => [ "crypto/evp.c" ],
622 incs => [ "include" ],
625 src2obj(obj => "crypto/cversion"
626 srcs => [ "crypto/cversion.c" ],
627 deps => [ "crypto/buildinf.h" ],
628 incs => [ "include" ],
631 generatesrc(src => "crypto/buildinf.h",
632 generator => [ "util/mkbuildinf.pl", "\"$(CC)",
633 "$(CFLAGS)\"", "\"$(PLATFORM)\"" ],
634 generator_incs => [ "util" ],
635 generator_deps => [ "util/Foo.pm" ],
640 The returned strings from all those calls are then concatenated
641 together and written to the resulting build-file.