| Message ID | 20170404172706.171971-1-mka@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
El Tue, Apr 04, 2017 at 10:27:06AM -0700 Matthias Kaehlcke ha dit: > From: Vinícius Tinti <viniciustinti@gmail.com> > > Add rules to kbuild in order to generate LLVM bitcode files with the .ll > extension when using clang. > > # from c code > CC=clang make kernel/pid.ll > > # from asm code > CC=clang make arch/x86/kernel/preempt.ll > > From: Vinícius Tinti <viniciustinti@gmail.com> > Signed-off-by: Vinícius Tinti <viniciustinti@gmail.com> > Signed-off-by: Behan Webster <behanw@converseincode.com> > Signed-off-by: Matthias Kaehlcke <mka@chromium.org> > --- Ping, any comments on this patch? Thanks Matthias -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Matthias, 2017-04-05 2:27 GMT+09:00 Matthias Kaehlcke <mka@chromium.org>: > From: Vinícius Tinti <viniciustinti@gmail.com> > > Add rules to kbuild in order to generate LLVM bitcode files with the .ll > extension when using clang. First, I'd like to be sure about the terminology "LLVM bitcode" because "bitcode" sounds like human-unreadable binary. For example, 'man llvm-as' says: llvm-as is the LLVM assembler. It reads a file containing human-readable LLVM assembly language, translates it to LLVM bitcode, and writes the result into a file or to standard output. As far as I understood: *.ll - LLVM assembly (human readable file) *.bc - LLVM bitcode (binary file) Is this correct? > # from c code > CC=clang make kernel/pid.ll This does not work because CC is overridden in the top-level Makefile. It should be make CC=clang kernel/pid.ll > # from asm code > CC=clang make arch/x86/kernel/preempt.ll arch/x86/kernel/preempt.* does not exist (at least in the latest tree). > + > +quiet_cmd_as_ll_S = CPP $(quiet_modtag) $@ > + cmd_as_ll_S = $(CPP) $(a_flags) -o $@ $< > + > +$(obj)/%.ll: $(src)/%.S FORCE > + $(call if_changed_dep,as_ll_S) > + I could not understand how this rule can convert architecture-specific assembly to LLVM intermediate expression. This is just pre-processing *.S file. Actually, this is completely the same as the rule *.S -> *.s quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< $(obj)/%.s: $(src)/%.S FORCE $(call if_changed_dep,cpp_s_S)
Hi Masahiro, El Fri, Apr 21, 2017 at 02:02:46PM +0900 Masahiro Yamada ha dit: > 2017-04-05 2:27 GMT+09:00 Matthias Kaehlcke <mka@chromium.org>: > > From: Vinícius Tinti <viniciustinti@gmail.com> > > > > Add rules to kbuild in order to generate LLVM bitcode files with the .ll > > extension when using clang. > > > First, I'd like to be sure about the terminology "LLVM bitcode" > because "bitcode" sounds like human-unreadable binary. > > > For example, 'man llvm-as' says: > llvm-as is the LLVM assembler. It reads a file containing > human-readable LLVM assembly language, translates it to LLVM > bitcode, and writes the result into a file or to standard output. > > > As far as I understood: > > *.ll - LLVM assembly (human readable file) > *.bc - LLVM bitcode (binary file) > > Is this correct? Yes, the terminology should be changed to talk about 'LLVM assembly'. > > # from c code > > CC=clang make kernel/pid.ll > > This does not work because CC is overridden in the top-level Makefile. > It should be > make CC=clang kernel/pid.ll Will change > > # from asm code > > CC=clang make arch/x86/kernel/preempt.ll > > arch/x86/kernel/preempt.* does not exist > (at least in the latest tree). > > > > > > + > > +quiet_cmd_as_ll_S = CPP $(quiet_modtag) $@ > > + cmd_as_ll_S = $(CPP) $(a_flags) -o $@ $< > > + > > +$(obj)/%.ll: $(src)/%.S FORCE > > + $(call if_changed_dep,as_ll_S) > > + > > I could not understand how this rule can convert > architecture-specific assembly to LLVM intermediate expression. > > This is just pre-processing *.S file. > > > Actually, this is completely the same as the rule *.S -> *.s > > quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ > cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< > > $(obj)/%.s: $(src)/%.S FORCE > $(call if_changed_dep,cpp_s_S) Indeed, unsurprisingly the content of a .ll file generated from a .S is the same as the corresponding .s. Besides the Makefile rules it isn't clear to me how assembly would be converted to LLVM IR. I suggest to remove the rules for assembly. Cheers Matthias -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Matthias, 2017-04-22 4:55 GMT+09:00 Matthias Kaehlcke <mka@chromium.org>: > Hi Masahiro, > > El Fri, Apr 21, 2017 at 02:02:46PM +0900 Masahiro Yamada ha dit: > >> 2017-04-05 2:27 GMT+09:00 Matthias Kaehlcke <mka@chromium.org>: >> > From: Vinícius Tinti <viniciustinti@gmail.com> >> > >> > Add rules to kbuild in order to generate LLVM bitcode files with the .ll >> > extension when using clang. >> >> >> First, I'd like to be sure about the terminology "LLVM bitcode" >> because "bitcode" sounds like human-unreadable binary. >> >> >> For example, 'man llvm-as' says: >> llvm-as is the LLVM assembler. It reads a file containing >> human-readable LLVM assembly language, translates it to LLVM >> bitcode, and writes the result into a file or to standard output. >> >> >> As far as I understood: >> >> *.ll - LLVM assembly (human readable file) >> *.bc - LLVM bitcode (binary file) >> >> Is this correct? > > Yes, the terminology should be changed to talk about 'LLVM assembly'. > >> > # from c code >> > CC=clang make kernel/pid.ll >> >> This does not work because CC is overridden in the top-level Makefile. >> It should be >> make CC=clang kernel/pid.ll > > Will change > >> > # from asm code >> > CC=clang make arch/x86/kernel/preempt.ll >> >> arch/x86/kernel/preempt.* does not exist >> (at least in the latest tree). >> >> >> >> >> > + >> > +quiet_cmd_as_ll_S = CPP $(quiet_modtag) $@ >> > + cmd_as_ll_S = $(CPP) $(a_flags) -o $@ $< >> > + >> > +$(obj)/%.ll: $(src)/%.S FORCE >> > + $(call if_changed_dep,as_ll_S) >> > + >> >> I could not understand how this rule can convert >> architecture-specific assembly to LLVM intermediate expression. >> >> This is just pre-processing *.S file. >> >> >> Actually, this is completely the same as the rule *.S -> *.s >> >> quiet_cmd_cpp_s_S = CPP $(quiet_modtag) $@ >> cmd_cpp_s_S = $(CPP) $(a_flags) -o $@ $< >> >> $(obj)/%.s: $(src)/%.S FORCE >> $(call if_changed_dep,cpp_s_S) > > Indeed, unsurprisingly the content of a .ll file generated from a .S > is the same as the corresponding .s. > > Besides the Makefile rules it isn't clear to me how assembly would be > converted to LLVM IR. I suggest to remove the rules for assembly. > I agree. This rule should be removed.
Hi Matthias, 2017-04-22 4:55 GMT+09:00 Matthias Kaehlcke <mka@chromium.org>: > Hi Masahiro, > > El Fri, Apr 21, 2017 at 02:02:46PM +0900 Masahiro Yamada ha dit: > >> 2017-04-05 2:27 GMT+09:00 Matthias Kaehlcke <mka@chromium.org>: >> > From: Vinícius Tinti <viniciustinti@gmail.com> >> > >> > Add rules to kbuild in order to generate LLVM bitcode files with the .ll >> > extension when using clang. >> >> >> First, I'd like to be sure about the terminology "LLVM bitcode" >> because "bitcode" sounds like human-unreadable binary. >> >> >> For example, 'man llvm-as' says: >> llvm-as is the LLVM assembler. It reads a file containing >> human-readable LLVM assembly language, translates it to LLVM >> bitcode, and writes the result into a file or to standard output. >> One more thing: Please add '*.ll' pattern to the following clean target. clean: $(clean-dirs) $(call cmd,rmdirs) $(call cmd,rmfiles) @find $(if $(KBUILD_EXTMOD), $(KBUILD_EXTMOD), .) $(RCS_FIND_IGNORE) \ \( -name '*.[oas]' -o -name '*.ko' -o -name '.*.cmd' \ -o -name '*.ko.*' \ -o -name '*.dwo' \ -o -name '*.su' \ -o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \ -o -name '*.symtypes' -o -name 'modules.order' \ -o -name modules.builtin -o -name '.tmp_*.o.*' \ -o -name '*.c.[012]*.*' \ -o -name '*.gcno' \) -type f -print | xargs rm -f
diff --git a/.gitignore b/.gitignore index c2ed4ecb0acd..0c39aa20b6ba 100644 --- a/.gitignore +++ b/.gitignore @@ -33,6 +33,7 @@ *.lzo *.patch *.gcno +*.ll modules.builtin Module.symvers *.dwo diff --git a/Makefile b/Makefile index e11989d36c87..d998ce363335 100644 --- a/Makefile +++ b/Makefile @@ -1361,6 +1361,8 @@ help: @echo ' (default: $$(INSTALL_MOD_PATH)/lib/firmware)' @echo ' dir/ - Build all files in dir and below' @echo ' dir/file.[ois] - Build specified target only' + @echo ' dir/file.ll - Build the LLVM bitcode file' + @echo ' (requires compiler support for LLVM bitcode generation)' @echo ' dir/file.lst - Build specified mixed source/assembly target only' @echo ' (requires a recent binutils and recent build (System.map))' @echo ' dir/file.ko - Build module including final link' @@ -1648,6 +1650,10 @@ endif $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@) %.symtypes: %.c prepare scripts FORCE $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@) +%.ll: %.c prepare scripts FORCE + $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@) +%.ll: %.S prepare scripts FORCE + $(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@) # Modules /: prepare scripts FORCE diff --git a/scripts/Makefile.build b/scripts/Makefile.build index d883116ebaa4..e5a28da2e6fa 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -177,6 +177,20 @@ cmd_cc_symtypes_c = \ $(obj)/%.symtypes : $(src)/%.c FORCE $(call cmd,cc_symtypes_c) +# LLVM bitcode +# Generate .ll files from .s and .c +quiet_cmd_cc_ll_c = CC $(quiet_modtag) $@ + cmd_cc_ll_c = $(CC) $(c_flags) -emit-llvm -S -o $@ $< + +$(obj)/%.ll: $(src)/%.c FORCE + $(call if_changed_dep,cc_ll_c) + +quiet_cmd_as_ll_S = CPP $(quiet_modtag) $@ + cmd_as_ll_S = $(CPP) $(a_flags) -o $@ $< + +$(obj)/%.ll: $(src)/%.S FORCE + $(call if_changed_dep,as_ll_S) + # C (.c) files # The C file is compiled and updated dependency information is generated. # (See cmd_cc_o_c + relevant part of rule_cc_o_c)