[PATCH] kbuild: add support to generate LLVM bitcode files

[PATCH] kbuild: add support to generate LLVM bitcode files

[Vinícius Tinti]

Allows kbuild to generate LLVM bitcode files with the .ll extension when
building with Clang.

  # c code
  CC=clang make kernel/pid.ll

  # asm code
  CC=clang make arch/arm/kernel/calls.ll

Signed-off-by: Vinícius Tinti <viniciustinti@gmail.com>
Signed-off-by: Behan Webster <behanw@converseincode.com>
---
 Makefile               |  7 +++++++
 scripts/Makefile.build | 18 ++++++++++++++++++
 2 files changed, 25 insertions(+)

diff --git a/Makefile b/Makefile
index f3c543d..4eb0d14 100644
--- a/Makefile
+++ b/Makefile
@@ -1484,6 +1484,13 @@ endif
 %.symtypes: %.c prepare scripts FORCE
 	$(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
 
+ifeq ($(COMPILER),clang)
+%.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 $@)
+endif
+
 # Modules
 /: prepare scripts FORCE
 	$(cmd_crmodverdir)
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index bf3e677..9ea19d6 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -174,6 +174,14 @@ cmd_cc_symtypes_c =                                                         \
 $(obj)/%.symtypes : $(src)/%.c FORCE
 	$(call cmd,cc_symtypes_c)
 
+ifeq ($(COMPILER),clang)
+quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
+cmd_cc_ll_c       = $(CC) $(c_flags) $(DISABLE_LTO) -fverbose-asm -emit-llvm -S -o $@ $<
+
+$(obj)/%.ll: $(src)/%.c FORCE
+	$(call if_changed_dep,cc_ll_c)
+endif
+
 # 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)
@@ -315,6 +323,16 @@ quiet_cmd_asn1_compiler = ASN.1   $@
 $(obj)/%-asn1.c $(obj)/%-asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
 	$(call cmd,asn1_compiler)
 
+# LLVM bitcode
+# ---------------------------------------------------------------------------
+ifeq ($(COMPILER),clang)
+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)
+endif
+
 # Build the compiled-in targets
 # ---------------------------------------------------------------------------
 
-- 
2.0.1

Re: [PATCH] kbuild: add support to generate LLVM bitcode files

[Sam Ravnborg]

On Fri, Jul 18, 2014 at 10:34:37PM -0300, Vinícius Tinti wrote:
> Allows kbuild to generate LLVM bitcode files with the .ll extension when
> building with Clang.
> 
>   # c code
>   CC=clang make kernel/pid.ll
> 
>   # asm code
>   CC=clang make arch/arm/kernel/calls.ll
> 
> Signed-off-by: Vinícius Tinti <viniciustinti@gmail.com>
> Signed-off-by: Behan Webster <behanw@converseincode.com>
> ---
>  Makefile               |  7 +++++++
>  scripts/Makefile.build | 18 ++++++++++++++++++
>  2 files changed, 25 insertions(+)
> 
> diff --git a/Makefile b/Makefile
> index f3c543d..4eb0d14 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1484,6 +1484,13 @@ endif
>  %.symtypes: %.c prepare scripts FORCE
>  	$(Q)$(MAKE) $(build)=$(build-dir) $(target-dir)$(notdir $@)
>  
> +ifeq ($(COMPILER),clang)
> +%.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 $@)
> +endif
Can we drop the test for $(COMPILER) here?
If one try this with gcc then gcc will just fail if it do not support the clang flags supplied.

And help section should be updated to list .ll too.


> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> index bf3e677..9ea19d6 100644
> --- a/scripts/Makefile.build
> +++ b/scripts/Makefile.build
> @@ -174,6 +174,14 @@ cmd_cc_symtypes_c =                                                         \
>  $(obj)/%.symtypes : $(src)/%.c FORCE
>  	$(call cmd,cc_symtypes_c)
>  
> +ifeq ($(COMPILER),clang)
> +quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
> +cmd_cc_ll_c       = $(CC) $(c_flags) $(DISABLE_LTO) -fverbose-asm -emit-llvm -S -o $@ $<

Can we drop the test for COMPILER here too?
Do -fverbose-asm make sense when generating .ll files?
It looks like a leftover from what you copied.


> +# LLVM bitcode
> +# ---------------------------------------------------------------------------
> +ifeq ($(COMPILER),clang)
> +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)
> +endif
This chunk belongs together with the other chunk.
There is no reason to separate .S => .ll and .c => .ll rules.

The current rules for .c => .lst etc is a mess and not something to be too
much inspired from.

	Sam

Re: [PATCH] kbuild: add support to generate LLVM bitcode files

[Sam Ravnborg]

> >  
> > +ifeq ($(COMPILER),clang)
> > +quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
> > +cmd_cc_ll_c       = $(CC) $(c_flags) $(DISABLE_LTO) -fverbose-asm -emit-llvm -S -o $@ $<
> 
> Can we drop the test for COMPILER here too?
> Do -fverbose-asm make sense when generating .ll files?
> It looks like a leftover from what you copied.

Also  $(DISABLE_LTO) looks like a left-over.
It was added to avoid LTO when generating asm-offstes.s which
the original rule is also used for.
So this should be skipped too.

	Sam

Re: [PATCH] kbuild: add support to generate LLVM bitcode files

[Sam Ravnborg]

On Sun, Jul 20, 2014 at 11:04:58PM +0200, Sam Ravnborg wrote:
> > >  
> > > +ifeq ($(COMPILER),clang)
> > > +quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
> > > +cmd_cc_ll_c       = $(CC) $(c_flags) $(DISABLE_LTO) -fverbose-asm -emit-llvm -S -o $@ $<
> > 
> > Can we drop the test for COMPILER here too?
> > Do -fverbose-asm make sense when generating .ll files?
> > It looks like a leftover from what you copied.
> 
> Also  $(DISABLE_LTO) looks like a left-over.
> It was added to avoid LTO when generating asm-offstes.s which
> the original rule is also used for.
> So this should be skipped too.
Third thing.
In some places we indent the assignmnet like this:
quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
      cmd_cc_ll_c = $(CC) $(c_flags) ....

This makes it more obvious that the "cmd_cc_ll_c" is actually the same.
Makefile.build does not do this much but please do for these targets.

	Sam

Re: [PATCH] kbuild: add support to generate LLVM bitcode files

[Tinti]

1) Can we drop the test for $(COMPILER) here?

Yes.

2) And help section should be updated to list .ll too.

I will be adding it too.

3) This chunk belongs together with the other chunk.
There is no reason to separate .S => .ll and .c => .ll rules.

Sure. But in fact I was not able to create the .ll from .S and neither
create the .s
from the .S in some assembly files on kernel. Do you know how it works?

4) Also $(DISABLE_LTO) looks like a left-over.

Remove $(DISABLE_LTO)

5) quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
      cmd_cc_ll_c = $(CC) $(c_flags) ....

Understood.

Thanks.

On Sun, Jul 20, 2014 at 6:30 PM, Sam Ravnborg <sam@ravnborg.org> wrote:
> On Sun, Jul 20, 2014 at 11:04:58PM +0200, Sam Ravnborg wrote:
>> > >
>> > > +ifeq ($(COMPILER),clang)
>> > > +quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
>> > > +cmd_cc_ll_c       = $(CC) $(c_flags) $(DISABLE_LTO) -fverbose-asm -emit-llvm -S -o $@ $<
>> >
>> > Can we drop the test for COMPILER here too?
>> > Do -fverbose-asm make sense when generating .ll files?
>> > It looks like a leftover from what you copied.
>>
>> Also  $(DISABLE_LTO) looks like a left-over.
>> It was added to avoid LTO when generating asm-offstes.s which
>> the original rule is also used for.
>> So this should be skipped too.
> Third thing.
> In some places we indent the assignmnet like this:
> quiet_cmd_cc_ll_c = CC $(quiet_modtag)  $@
>       cmd_cc_ll_c = $(CC) $(c_flags) ....
>
> This makes it more obvious that the "cmd_cc_ll_c" is actually the same.
> Makefile.build does not do this much but please do for these targets.
>
>         Sam



-- 
Simplicity is the ultimate sophistication

Re: [PATCH] kbuild: add support to generate LLVM bitcode files

[Sam Ravnborg]

> 
> Sure. But in fact I was not able to create the .ll from .S and neither
> create the .s
> from the .S in some assembly files on kernel. Do you know how it works?

   make arch/x86/kernel/preempt.s

Works for me.
Something broke in your setup?

	Sam

[PATCH v2] kbuild: add support to generate LLVM bitcode files

[Vinícius Tinti]

Allows kbuild to generate LLVM bitcode files with the .ll extension.

  # from c code
  CC=clang make kernel/pid.ll

  # from asm code
  CC=clang make arch/x86/kernel/preempt.ll

Signed-off-by: Vinícius Tinti <viniciustinti@gmail.com>
Signed-off-by: Behan Webster <behanw@converseincode.com>
---
 .gitignore             |  1 +
 Makefile               |  6 ++++++
 scripts/Makefile.build | 14 ++++++++++++++
 3 files changed, 21 insertions(+)

diff --git a/.gitignore b/.gitignore
index f4c0b09..c5a7656 100644
--- a/.gitignore
+++ b/.gitignore
@@ -32,6 +32,7 @@
 *.lzo
 *.patch
 *.gcno
+*.ll
 modules.builtin
 Module.symvers
 
diff --git a/Makefile b/Makefile
index 6b27741..7826c33 100644
--- a/Makefile
+++ b/Makefile
@@ -1213,6 +1213,8 @@ help:
 	@echo  '                    (default: $$(INSTALL_MOD_PATH)/lib/firmware)'
 	@echo  '  dir/            - Build all files in dir and below'
 	@echo  '  dir/file.[oisS] - Build specified target only'
+	@echo  '  dir/file.ll     - Build the LLVM bitcode file'
+	@echo  '                    (requires a 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'
@@ -1483,6 +1485,10 @@ 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 bf3e677..4d97e4f 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -174,6 +174,20 @@ 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)
-- 
2.0.1

Re: [PATCH v2] kbuild: add support to generate LLVM bitcode files

[Tinti]

On Wed, Jul 23, 2014 at 8:56 AM, Vinícius Tinti <viniciustinti@gmail.com> wrote:
> Allows kbuild to generate LLVM bitcode files with the .ll extension.
>
>   # from c code
>   CC=clang make kernel/pid.ll
>
>   # from asm code
>   CC=clang make arch/x86/kernel/preempt.ll
>
> Signed-off-by: Vinícius Tinti <viniciustinti@gmail.com>
> Signed-off-by: Behan Webster <behanw@converseincode.com>
> ---
>  .gitignore             |  1 +
>  Makefile               |  6 ++++++
>  scripts/Makefile.build | 14 ++++++++++++++
>  3 files changed, 21 insertions(+)
>
> diff --git a/.gitignore b/.gitignore
> index f4c0b09..c5a7656 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -32,6 +32,7 @@
>  *.lzo
>  *.patch
>  *.gcno
> +*.ll
>  modules.builtin
>  Module.symvers
>
> diff --git a/Makefile b/Makefile
> index 6b27741..7826c33 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1213,6 +1213,8 @@ help:
>         @echo  '                    (default: $$(INSTALL_MOD_PATH)/lib/firmware)'
>         @echo  '  dir/            - Build all files in dir and below'
>         @echo  '  dir/file.[oisS] - Build specified target only'
> +       @echo  '  dir/file.ll     - Build the LLVM bitcode file'
> +       @echo  '                    (requires a 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'
> @@ -1483,6 +1485,10 @@ 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 bf3e677..4d97e4f 100644
> --- a/scripts/Makefile.build
> +++ b/scripts/Makefile.build
> @@ -174,6 +174,20 @@ 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)
> --
> 2.0.1
>

The preempt.s works for me as well the preempt.ll.

The make help now displays about the .ll files but I have not found
other section in Documentation about it. If there is please let me know.
I have also added the *.ll in .gitignore.

Regards

-- 
Simplicity is the ultimate sophistication

[PATCH v3] kbuild: add support to generate LLVM bitcode files

[Vinícius Tinti]

Allows kbuild to generate LLVM bitcode files using '.ll' suffix.

  # from c code
  CC=clang make kernel/pid.ll

  # from asm code
  CC=clang make arch/x86/kernel/preempt.ll

Signed-off-by: Vinícius Tinti <viniciustinti@gmail.com>
Signed-off-by: Behan Webster <behanw@converseincode.com>
---
 .gitignore             |  1 +
 Makefile               |  6 ++++++
 scripts/Makefile.build | 14 ++++++++++++++
 3 files changed, 21 insertions(+)

diff --git a/.gitignore b/.gitignore
index e213b27..823b9d6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -32,6 +32,7 @@
 *.lzo
 *.patch
 *.gcno
+*.ll
 modules.builtin
 Module.symvers
 *.dwo
diff --git a/Makefile b/Makefile
index 1a60bdd..cd4a120 100644
--- a/Makefile
+++ b/Makefile
@@ -1250,6 +1250,8 @@ help:
 	@echo  '                    (default: $$(INSTALL_MOD_PATH)/lib/firmware)'
 	@echo  '  dir/            - Build all files in dir and below'
 	@echo  '  dir/file.[oisS] - 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'
@@ -1526,6 +1528,10 @@ 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 bf3e677..4d97e4f 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -174,6 +174,20 @@ 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)
-- 
2.1.0