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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /tools/build/Documentation/Build.txt | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tools/build/Documentation/Build.txt')
-rw-r--r-- | tools/build/Documentation/Build.txt | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/tools/build/Documentation/Build.txt b/tools/build/Documentation/Build.txt new file mode 100644 index 000000000..a22587475 --- /dev/null +++ b/tools/build/Documentation/Build.txt @@ -0,0 +1,168 @@ +Build Framework +=============== + +The perf build framework was adopted from the kernel build system, hence the +idea and the way how objects are built is the same. + +Basically the user provides set of 'Build' files that list objects and +directories to nest for specific target to be build. + +Unlike the kernel we don't have a single build object 'obj-y' list that where +we setup source objects, but we support more. This allows one 'Build' file to +carry a sources list for multiple build objects. + + +Build framework makefiles +------------------------- + +The build framework consists of 2 Makefiles: + + Build.include + Makefile.build + +While the 'Build.include' file contains just some generic definitions, the +'Makefile.build' file is the makefile used from the outside. It's +interface/usage is following: + + $ make -f tools/build/Makefile.build srctree=$(KSRC) dir=$(DIR) obj=$(OBJECT) + +where: + + KSRC - is the path to kernel sources + DIR - is the path to the project to be built + OBJECT - is the name of the build object + +When succefully finished the $(DIR) directory contains the final object file +called $(OBJECT)-in.o: + + $ ls $(DIR)/$(OBJECT)-in.o + +which includes all compiled sources described in 'Build' makefiles. + + +Build makefiles +--------------- + +The user supplies 'Build' makefiles that contains a objects list, and connects +the build to nested directories. + +Assume we have the following project structure: + + ex/a.c + /b.c + /c.c + /d.c + /arch/e.c + /arch/f.c + +Out of which you build the 'ex' binary ' and the 'libex.a' library: + + 'ex' - consists of 'a.o', 'b.o' and libex.a + 'libex.a' - consists of 'c.o', 'd.o', 'e.o' and 'f.o' + +The build framework does not create the 'ex' and 'libex.a' binaries for you, it +only prepares proper objects to be compiled and grouped together. + +To follow the above example, the user provides following 'Build' files: + + ex/Build: + ex-y += a.o + ex-y += b.o + ex-y += b.o # duplicates in the lists are allowed + + libex-y += c.o + libex-y += d.o + libex-y += arch/ + + ex/arch/Build: + libex-y += e.o + libex-y += f.o + +and runs: + + $ make -f tools/build/Makefile.build dir=. obj=ex + $ make -f tools/build/Makefile.build dir=. obj=libex + +which creates the following objects: + + ex/ex-in.o + ex/libex-in.o + +that contain request objects names in Build files. + +It's only a matter of 2 single commands to create the final binaries: + + $ ar rcs libex.a libex-in.o + $ gcc -o ex ex-in.o libex.a + +You can check the 'ex' example in 'tools/build/tests/ex' for more details. + + +Makefile.include +---------------- + +The tools/build/Makefile.include makefile could be included +via user makefiles to get usefull definitions. + +It defines following interface: + + - build macro definition: + build := -f $(srctree)/tools/build/Makefile.build dir=. obj + + to make it easier to invoke build like: + make $(build)=ex + + +Fixdep +------ +It is necessary to build the fixdep helper before invoking the build. +The Makefile.include file adds the fixdep target, that could be +invoked by the user. + + +Rules +----- + +The build framework provides standard compilation rules to handle .S and .c +compilation. + +It's possible to include special rule if needed (like we do for flex or bison +code generation). + + +CFLAGS +------ + +It's possible to alter the standard object C flags in the following way: + + CFLAGS_perf.o += '...' - adds CFLAGS for perf.o object + CFLAGS_gtk += '...' - adds CFLAGS for gtk build object + CFLAGS_REMOVE_perf.o += '...' - removes CFLAGS for perf.o object + CFLAGS_REMOVE_gtk += '...' - removes CFLAGS for gtk build object + +This C flags changes has the scope of the Build makefile they are defined in. + + +Dependencies +------------ + +For each built object file 'a.o' the '.a.cmd' is created and holds: + + - Command line used to built that object + (for each object) + + - Dependency rules generated by 'gcc -Wp,-MD,...' + (for compiled object) + +All existing '.cmd' files are included in the Build process to follow properly +the dependencies and trigger a rebuild when necessary. + + +Single rules +------------ + +It's possible to build single object file by choice, like: + + $ make util/map.o # objects + $ make util/map.i # preprocessor + $ make util/map.s # assembly |