| Design document for the unified scheme data |
| =========================================== |
| |
| How are things connected? |
| ------------------------- |
| |
| The unified scheme takes all its data from the `build.info` files seen |
| throughout the source tree. These files hold the minimum information |
| needed to build end product files from diverse sources. See the |
| section on `build.info` files below. |
| |
| From the information in `build.info` files, `Configure` builds up an |
| information database as a hash table called `%unified_info`, which is |
| stored in configdata.pm, found at the top of the build tree (which may |
| or may not be the same as the source tree). |
| |
| [`Configurations/common.tmpl`](common.tmpl) uses the data from `%unified_info` to |
| generate the rules for building end product files as well as |
| intermediary files with the help of a few functions found in the |
| build-file templates. See the section on build-file templates further |
| down for more information. |
| |
| build.info files |
| ---------------- |
| |
| As mentioned earlier, `build.info` files are meant to hold the minimum |
| information needed to build output files, and therefore only (with a |
| few possible exceptions [1]) have information about end products (such |
| as scripts, library files and programs) and source files (such as C |
| files, C header files, assembler files, etc). Intermediate files such |
| as object files are rarely directly referred to in `build.info` files (and |
| when they are, it's always with the file name extension `.o`), they are |
| inferred by `Configure`. By the same rule of minimalism, end product |
| file name extensions (such as `.so`, `.a`, `.exe`, etc) are never mentioned |
| in `build.info`. Their file name extensions will be inferred by the |
| build-file templates, adapted for the platform they are meant for (see |
| sections on `%unified_info` and build-file templates further down). |
| |
| The variables `PROGRAMS`, `LIBS`, `MODULES` and `SCRIPTS` are used to declare |
| end products. There are variants for them with `_NO_INST` as suffix |
| (`PROGRAM_NO_INST` etc) to specify end products that shouldn't get installed. |
| |
| The variables `SOURCE`, `DEPEND`, `INCLUDE` and `DEFINE` are indexed by a |
| produced file, and their values are the source used to produce that |
| particular produced file, extra dependencies, include directories |
| needed, or C macros to be defined. |
| |
| All their values in all the `build.info` throughout the source tree are |
| collected together and form a set of programs, libraries, modules and |
| scripts to be produced, source files, dependencies, etc etc etc. |
| |
| Let's have a pretend example, a very limited contraption of OpenSSL, |
| composed of the program `apps/openssl`, the libraries `libssl` and |
| `libcrypto`, an module `engines/ossltest` and their sources and |
| dependencies. |
| |
| # build.info |
| LIBS=libcrypto libssl |
| INCLUDE[libcrypto]=include |
| INCLUDE[libssl]=include |
| DEPEND[libssl]=libcrypto |
| |
| This is the top directory `build.info` file, and it tells us that two |
| libraries are to be built, the include directory `include/` shall be |
| used throughout when building anything that will end up in each |
| library, and that the library `libssl` depend on the library |
| `libcrypto` to function properly. |
| |
| # apps/build.info |
| PROGRAMS=openssl |
| SOURCE[openssl]=openssl.c |
| INCLUDE[openssl]=.. ../include |
| DEPEND[openssl]=../libssl |
| |
| This is the `build.info` file in `apps/`, one may notice that all file |
| paths mentioned are relative to the directory the `build.info` file is |
| located in. This one tells us that there's a program to be built |
| called `apps/openss` (the file name extension will depend on the |
| platform and is therefore not mentioned in the `build.info` file). It's |
| built from one source file, `apps/openssl.c`, and building it requires |
| the use of `.` and `include/` include directories (both are declared |
| from the point of view of the `apps/` directory), and that the program |
| depends on the library `libssl` to function properly. |
| |
| # crypto/build.info |
| LIBS=../libcrypto |
| SOURCE[../libcrypto]=aes.c evp.c cversion.c |
| DEPEND[cversion.o]=buildinf.h |
| |
| GENERATE[buildinf.h]=../util/mkbuildinf.pl "$(CC) $(CFLAGS)" "$(PLATFORM)" |
| DEPEND[buildinf.h]=../Makefile |
| DEPEND[../util/mkbuildinf.pl]=../util/Foo.pm |
| |
| This is the `build.info` file in `crypto/`, and it tells us a little more |
| about what's needed to produce `libcrypto`. LIBS is used again to |
| declare that `libcrypto` is to be produced. This declaration is |
| really unnecessary as it's already mentioned in the top `build.info` |
| file, but can make the info file easier to understand. This is to |
| show that duplicate information isn't an issue. |
| |
| This `build.info` file informs us that `libcrypto` is built from a few |
| source files, `crypto/aes.c`, `crypto/evp.c` and `crypto/cversion.c`. |
| It also shows us that building the object file inferred from |
| `crypto/cversion.c` depends on `crypto/buildinf.h`. Finally, it |
| also shows the possibility to declare how some files are generated |
| using some script, in this case a perl script, and how such scripts |
| can be declared to depend on other files, in this case a perl module. |
| |
| Two things are worth an extra note: |
| |
| `DEPEND[cversion.o]` mentions an object file. DEPEND indexes is the |
| only location where it's valid to mention them |
| |
| # ssl/build.info |
| LIBS=../libssl |
| SOURCE[../libssl]=tls.c |
| |
| This is the build.info file in `ssl/`, and it tells us that the |
| library `libssl` is built from the source file `ssl/tls.c`. |
| |
| # engines/build.info |
| MODULES=dasync |
| SOURCE[dasync]=e_dasync.c |
| DEPEND[dasync]=../libcrypto |
| INCLUDE[dasync]=../include |
| |
| MODULES_NO_INST=ossltest |
| SOURCE[ossltest]=e_ossltest.c |
| DEPEND[ossltest]=../libcrypto.a |
| INCLUDE[ossltest]=../include |
| |
| This is the `build.info` file in `engines/`, telling us that two modules |
| called `engines/dasync` and `engines/ossltest` shall be built, that |
| `dasync`'s source is `engines/e_dasync.c` and `ossltest`'s source is |
| `engines/e_ossltest.c` and that the include directory `include/` may |
| be used when building anything that will be part of these modules. |
| Also, both modules depend on the library `libcrypto` to function |
| properly. `ossltest` is explicitly linked with the static variant of |
| the library `libcrypto`. Finally, only `dasync` is being installed, as |
| `ossltest` is only for internal testing. |
| |
| When `Configure` digests these `build.info` files, the accumulated |
| information comes down to this: |
| |
| LIBS=libcrypto libssl |
| SOURCE[libcrypto]=crypto/aes.c crypto/evp.c crypto/cversion.c |
| DEPEND[crypto/cversion.o]=crypto/buildinf.h |
| INCLUDE[libcrypto]=include |
| SOURCE[libssl]=ssl/tls.c |
| INCLUDE[libssl]=include |
| DEPEND[libssl]=libcrypto |
| |
| PROGRAMS=apps/openssl |
| SOURCE[apps/openssl]=apps/openssl.c |
| INCLUDE[apps/openssl]=. include |
| DEPEND[apps/openssl]=libssl |
| |
| MODULES=engines/dasync |
| SOURCE[engines/dasync]=engines/e_dasync.c |
| DEPEND[engines/dasync]=libcrypto |
| INCLUDE[engines/dasync]=include |
| |
| MODULES_NO_INST=engines/ossltest |
| SOURCE[engines/ossltest]=engines/e_ossltest.c |
| DEPEND[engines/ossltest]=libcrypto.a |
| INCLUDE[engines/ossltest]=include |
| |
| GENERATE[crypto/buildinf.h]=util/mkbuildinf.pl "$(CC) $(CFLAGS)" "$(PLATFORM)" |
| DEPEND[crypto/buildinf.h]=Makefile |
| DEPEND[util/mkbuildinf.pl]=util/Foo.pm |
| |
| A few notes worth mentioning: |
| |
| `LIBS` may be used to declare routine libraries only. |
| |
| `PROGRAMS` may be used to declare programs only. |
| |
| `MODULES` may be used to declare modules only. |
| |
| The indexes for `SOURCE` must only be end product files, such as |
| libraries, programs or modules. The values of `SOURCE` variables must |
| only be source files (possibly generated). |
| |
| `INCLUDE` and `DEPEND` shows a relationship between different files |
| (usually produced files) or between files and directories, such as a |
| program depending on a library, or between an object file and some |
| extra source file. |
| |
| When `Configure` processes the `build.info` files, it will take it as |
| truth without question, and will therefore perform very few checks. |
| If the build tree is separate from the source tree, it will assume |
| that all built files and up in the build directory and that all source |
| files are to be found in the source tree, if they can be found there. |
| `Configure` will assume that source files that can't be found in the |
| source tree (such as `crypto/bildinf.h` in the example above) are |
| generated and will be found in the build tree. |
| |
| The `%unified_info` database |
| ---------------------------- |
| |
| The information in all the `build.info` get digested by `Configure` and |
| collected into the `%unified_info` database, divided into the following |
| indexes: |
| |
| depends => a hash table containing 'file' => [ 'dependency' ... ] |
| pairs. These are directly inferred from the DEPEND |
| variables in build.info files. |
| |
| modules => a list of modules. These are directly inferred from |
| the MODULES variable in build.info files. |
| |
| generate => a hash table containing 'file' => [ 'generator' ... ] |
| pairs. These are directly inferred from the GENERATE |
| variables in build.info files. |
| |
| includes => a hash table containing 'file' => [ 'include' ... ] |
| pairs. These are directly inferred from the INCLUDE |
| variables in build.info files. |
| |
| install => a hash table containing 'type' => [ 'file' ... ] pairs. |
| The types are 'programs', 'libraries', 'modules' and |
| 'scripts', and the array of files list the files of |
| that type that should be installed. |
| |
| libraries => a list of libraries. These are directly inferred from |
| the LIBS variable in build.info files. |
| |
| programs => a list of programs. These are directly inferred from |
| the PROGRAMS variable in build.info files. |
| |
| scripts => a list of scripts. There are directly inferred from |
| the SCRIPTS variable in build.info files. |
| |
| sources => a hash table containing 'file' => [ 'sourcefile' ... ] |
| pairs. These are indirectly inferred from the SOURCE |
| variables in build.info files. Object files are |
| mentioned in this hash table, with source files from |
| SOURCE variables, and AS source files for programs and |
| libraries. |
| |
| shared_sources => |
| a hash table just like 'sources', but only as source |
| files (object files) for building shared libraries. |
| |
| As an example, here is how the `build.info` files example from the |
| section above would be digested into a `%unified_info` table: |
| |
| our %unified_info = ( |
| "depends" => |
| { |
| "apps/openssl" => |
| [ |
| "libssl", |
| ], |
| "crypto/buildinf.h" => |
| [ |
| "Makefile", |
| ], |
| "crypto/cversion.o" => |
| [ |
| "crypto/buildinf.h", |
| ], |
| "engines/dasync" => |
| [ |
| "libcrypto", |
| ], |
| "engines/ossltest" => |
| [ |
| "libcrypto.a", |
| ], |
| "libssl" => |
| [ |
| "libcrypto", |
| ], |
| "util/mkbuildinf.pl" => |
| [ |
| "util/Foo.pm", |
| ], |
| }, |
| "modules" => |
| [ |
| "engines/dasync", |
| "engines/ossltest", |
| ], |
| "generate" => |
| { |
| "crypto/buildinf.h" => |
| [ |
| "util/mkbuildinf.pl", |
| "\"\$(CC)", |
| "\$(CFLAGS)\"", |
| "\"$(PLATFORM)\"", |
| ], |
| }, |
| "includes" => |
| { |
| "apps/openssl" => |
| [ |
| ".", |
| "include", |
| ], |
| "engines/ossltest" => |
| [ |
| "include" |
| ], |
| "libcrypto" => |
| [ |
| "include", |
| ], |
| "libssl" => |
| [ |
| "include", |
| ], |
| "util/mkbuildinf.pl" => |
| [ |
| "util", |
| ], |
| } |
| "install" => |
| { |
| "modules" => |
| [ |
| "engines/dasync", |
| ], |
| "libraries" => |
| [ |
| "libcrypto", |
| "libssl", |
| ], |
| "programs" => |
| [ |
| "apps/openssl", |
| ], |
| }, |
| "libraries" => |
| [ |
| "libcrypto", |
| "libssl", |
| ], |
| "programs" => |
| [ |
| "apps/openssl", |
| ], |
| "sources" => |
| { |
| "apps/openssl" => |
| [ |
| "apps/openssl.o", |
| ], |
| "apps/openssl.o" => |
| [ |
| "apps/openssl.c", |
| ], |
| "crypto/aes.o" => |
| [ |
| "crypto/aes.c", |
| ], |
| "crypto/cversion.o" => |
| [ |
| "crypto/cversion.c", |
| ], |
| "crypto/evp.o" => |
| [ |
| "crypto/evp.c", |
| ], |
| "engines/e_dasync.o" => |
| [ |
| "engines/e_dasync.c", |
| ], |
| "engines/dasync" => |
| [ |
| "engines/e_dasync.o", |
| ], |
| "engines/e_ossltest.o" => |
| [ |
| "engines/e_ossltest.c", |
| ], |
| "engines/ossltest" => |
| [ |
| "engines/e_ossltest.o", |
| ], |
| "libcrypto" => |
| [ |
| "crypto/aes.c", |
| "crypto/cversion.c", |
| "crypto/evp.c", |
| ], |
| "libssl" => |
| [ |
| "ssl/tls.c", |
| ], |
| "ssl/tls.o" => |
| [ |
| "ssl/tls.c", |
| ], |
| }, |
| ); |
| |
| As can be seen, everything in `%unified_info` is fairly simple suggest |
| of information. Still, it tells us that to build all programs, we |
| must build `apps/openssl`, and to build the latter, we will need to |
| build all its sources (`apps/openssl.o` in this case) and all the |
| other things it depends on (such as `libssl`). All those dependencies |
| need to be built as well, using the same logic, so to build `libssl`, |
| we need to build `ssl/tls.o` as well as `libcrypto`, and to build the |
| latter... |
| |
| Build-file templates |
| -------------------- |
| |
| Build-file templates are essentially build-files (such as `Makefile` on |
| Unix) with perl code fragments mixed in. Those perl code fragment |
| will generate all the configuration dependent data, including all the |
| rules needed to build end product files and intermediary files alike. |
| At a minimum, there must be a perl code fragment that defines a set of |
| functions that are used to generates specific build-file rules, to |
| build static libraries from object files, to build shared libraries |
| from static libraries, to programs from object files and libraries, |
| etc. |
| |
| generatesrc - function that produces build file lines to generate |
| a source file from some input. |
| |
| It's called like this: |
| |
| generatesrc(src => "PATH/TO/tobegenerated", |
| generator => [ "generatingfile", ... ] |
| generator_incs => [ "INCL/PATH", ... ] |
| generator_deps => [ "dep1", ... ] |
| incs => [ "INCL/PATH", ... ], |
| deps => [ "dep1", ... ], |
| intent => one of "libs", "dso", "bin" ); |
| |
| 'src' has the name of the file to be generated. |
| 'generator' is the command or part of command to |
| generate the file, of which the first item is |
| expected to be the file to generate from. |
| generatesrc() is expected to analyse and figure out |
| exactly how to apply that file and how to capture |
| the result. 'generator_incs' and 'generator_deps' |
| are include directories and files that the generator |
| file itself depends on. 'incs' and 'deps' are |
| include directories and files that are used if $(CC) |
| is used as an intermediary step when generating the |
| end product (the file indicated by 'src'). 'intent' |
| indicates what the generated file is going to be |
| used for. |
| |
| src2obj - function that produces build file lines to build an |
| object file from source files and associated data. |
| |
| It's called like this: |
| |
| src2obj(obj => "PATH/TO/objectfile", |
| srcs => [ "PATH/TO/sourcefile", ... ], |
| deps => [ "dep1", ... ], |
| incs => [ "INCL/PATH", ... ] |
| intent => one of "lib", "dso", "bin" ); |
| |
| 'obj' has the intended object file with `.o` |
| extension, src2obj() is expected to change it to |
| something more suitable for the platform. |
| 'srcs' has the list of source files to build the |
| object file, with the first item being the source |
| file that directly corresponds to the object file. |
| 'deps' is a list of explicit dependencies. 'incs' |
| is a list of include file directories. Finally, |
| 'intent' indicates what this object file is going |
| to be used for. |
| |
| obj2lib - function that produces build file lines to build a |
| static library file ("libfoo.a" in Unix terms) from |
| object files. |
| |
| called like this: |
| |
| obj2lib(lib => "PATH/TO/libfile", |
| objs => [ "PATH/TO/objectfile", ... ]); |
| |
| 'lib' has the intended library file name *without* |
| extension, obj2lib is expected to add that. 'objs' |
| has the list of object files to build this library. |
| |
| libobj2shlib - backward compatibility function that's used the |
| same way as obj2shlib (described next), and was |
| expected to build the shared library from the |
| corresponding static library when that was suitable. |
| NOTE: building a shared library from a static |
| library is now DEPRECATED, as they no longer share |
| object files. Attempting to do this will fail. |
| |
| obj2shlib - function that produces build file lines to build a |
| shareable object library file ("libfoo.so" in Unix |
| terms) from the corresponding object files. |
| |
| called like this: |
| |
| obj2shlib(shlib => "PATH/TO/shlibfile", |
| lib => "PATH/TO/libfile", |
| objs => [ "PATH/TO/objectfile", ... ], |
| deps => [ "PATH/TO/otherlibfile", ... ]); |
| |
| 'lib' has the base (static) library file name |
| *without* extension. This is useful in case |
| supporting files are needed (such as import |
| libraries on Windows). |
| 'shlib' has the corresponding shared library name |
| *without* extension. 'deps' has the list of other |
| libraries (also *without* extension) this library |
| needs to be linked with. 'objs' has the list of |
| object files to build this library. |
| |
| obj2dso - function that produces build file lines to build a |
| dynamic shared object file from object files. |
| |
| called like this: |
| |
| obj2dso(lib => "PATH/TO/libfile", |
| objs => [ "PATH/TO/objectfile", ... ], |
| deps => [ "PATH/TO/otherlibfile", |
| ... ]); |
| |
| This is almost the same as obj2shlib, but the |
| intent is to build a shareable library that can be |
| loaded in runtime (a "plugin"...). |
| |
| obj2bin - function that produces build file lines to build an |
| executable file from object files. |
| |
| called like this: |
| |
| obj2bin(bin => "PATH/TO/binfile", |
| objs => [ "PATH/TO/objectfile", ... ], |
| deps => [ "PATH/TO/libfile", ... ]); |
| |
| 'bin' has the intended executable file name |
| *without* extension, obj2bin is expected to add |
| that. 'objs' has the list of object files to build |
| this library. 'deps' has the list of library files |
| (also *without* extension) that the programs needs |
| to be linked with. |
| |
| in2script - function that produces build file lines to build a |
| script file from some input. |
| |
| called like this: |
| |
| in2script(script => "PATH/TO/scriptfile", |
| sources => [ "PATH/TO/infile", ... ]); |
| |
| 'script' has the intended script file name. |
| 'sources' has the list of source files to build the |
| resulting script from. |
| |
| Along with the build-file templates is the driving template |
| [`Configurations/common.tmpl`](common.tmpl), which looks through all the |
| information in `%unified_info` and generates all the rulesets to build libraries, |
| programs and all intermediate files, using the rule generating |
| functions defined in the build-file template. |
| |
| As an example with the smaller `build.info` set we've seen as an |
| example, producing the rules to build `libcrypto` would result in the |
| following calls: |
| |
| # Note: obj2shlib will only be called if shared libraries are |
| # to be produced. |
| # Note 2: obj2shlib must convert the '.o' extension to whatever |
| # is suitable on the local platform. |
| obj2shlib(shlib => "libcrypto", |
| objs => [ "crypto/aes.o", "crypto/evp.o", "crypto/cversion.o" ], |
| deps => [ ]); |
| |
| obj2lib(lib => "libcrypto" |
| objs => [ "crypto/aes.o", "crypto/evp.o", "crypto/cversion.o" ]); |
| |
| src2obj(obj => "crypto/aes.o" |
| srcs => [ "crypto/aes.c" ], |
| deps => [ ], |
| incs => [ "include" ], |
| intent => "lib"); |
| |
| src2obj(obj => "crypto/evp.o" |
| srcs => [ "crypto/evp.c" ], |
| deps => [ ], |
| incs => [ "include" ], |
| intent => "lib"); |
| |
| src2obj(obj => "crypto/cversion.o" |
| srcs => [ "crypto/cversion.c" ], |
| deps => [ "crypto/buildinf.h" ], |
| incs => [ "include" ], |
| intent => "lib"); |
| |
| generatesrc(src => "crypto/buildinf.h", |
| generator => [ "util/mkbuildinf.pl", "\"$(CC)", |
| "$(CFLAGS)\"", "\"$(PLATFORM)\"" ], |
| generator_incs => [ "util" ], |
| generator_deps => [ "util/Foo.pm" ], |
| incs => [ ], |
| deps => [ ], |
| intent => "lib"); |
| |
| The returned strings from all those calls are then concatenated |
| together and written to the resulting build-file. |
