[Debian] Compiler bug: genassym.c -> assym.S

[wargio]

I have a this problem on debian:
when i compile the assym.S is totally empty.
looks like the compiler removes the macro when it expands it.
file: https://github.com/darwin-on-arm/xnu/blob/master/osfmk/arm/genassym.c#L111

#define DECLARE(SYM,VAL) \
    __asm("#DEFINITION##define " SYM "\t%0" : : "n" ((u_int)(VAL)))
#endif

i fixed it in this way:
on that file it becomes:

#define DECLARE(SYM,VAL) \
    __asm(".file \"#DEFINITION##define " SYM "       %0####\"" : : "n" ((u_int)(VAL)))
#endif

and i changed the makefile template:
File: https://github.com/darwin-on-arm/xnu/blob/master/osfmk/conf/Makefile.template#L123

$(_v)sed -e '/#DEFINITION#/!d' -e 's/^.*#DEFINITION#//' -e 's/\$$//' -e 'p' -e 's/#//2' -e 's/[^A-Za-z0-9_]*\([A-Za-z0-9_]*\)/ \1_NUM/2' genassym.o > ${@}

to

$(_v)sed -e '/.file\s*\"#DEFINITION#/!d' -e 's/^.*#DEFINITION#//' -e 's/####\"//' -e 's/\$$//' -e 'p' -e 's/#//2' -e 's/[^A-Za-z0-9_]*\([A-Za-z0-9_]*\)/ \1_NUM/2' genassym.o > ${@}

Anybody knows a better why to fix this?

[nightsuns]

below is my fix:

---

osfmk/arm/genassym.c | 7 +++++--
osfmk/conf/Makefile.template | 4 +++-
2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/osfmk/arm/genassym.c b/osfmk/arm/genassym.c
index 9b3d063..d3f46d9 100644
--- a/osfmk/arm/genassym.c
+++ b/osfmk/arm/genassym.c
@@ -108,8 +108,11 @@
#define DECLARE(SYM,VAL)
__asm("#DEFINITION#\t.set\t" SYM ",\t%0" : : "n" ((u_int)(VAL)))
#else
+//#define DECLARE(SYM,VAL)
+// __asm("#DEFINITION##define " SYM "\t%0" : : "n" ((u_int)(VAL)))
#define DECLARE(SYM,VAL) \

• __asm("#DEFINITION##define " SYM "\t%0" : : "n" ((u_int)(VAL)))

•    __asm("DEFINITION__define__" SYM ":\t .ascii \"%0\"" : : "n"  ((u_int)(VAL)))
  

  #endif

  int main(int argc, char *_argv);
  @@ -129,7 +132,7 @@ int main(int argc, char *_argv)
  DECLARE("MUTEX_STATE", offsetof(lck_mtx_t *, lck_mtx_state));

  DECLARE("MUTEX_IND", LCK_MTX_TAG_INDIRECT);

• DECLARE("MUTEX_PTR", offsetof(lck_mtx_t *, lck_mtx_ptr));
  +// DECLARE("MUTEX_PTR", offsetof(lck_mtx_t *, lck_mtx_ptr));
  DECLARE("MUTEX_ASSERT_OWNED", LCK_MTX_ASSERT_OWNED);
  DECLARE("MUTEX_ASSERT_NOTOWNED", LCK_MTX_ASSERT_NOTOWNED);
  DECLARE("GRP_MTX_STAT_UTIL",
  diff --git a/osfmk/conf/Makefile.template b/osfmk/conf/Makefile.template
  index c39e844..a04f213 100644
  --- a/osfmk/conf/Makefile.template
  +++ b/osfmk/conf/Makefile.template
  @@ -117,10 +117,12 @@ GENASSYM_LOCATION = i386
  endif

genassym.o: $(SOURCE_DIR)/$(COMPONENT)/$(GENASSYM_LOCATION)/genassym.c

• @echo $(_v)${KCC} $(subst -flto,,${CFLAGS}) -MD ${_HOST_EXTRA_CFLAGS} -S -o ${@} -c ${INCFLAGS} $<
  $(_v)${KCC} $(subst -flto,,${CFLAGS}) -MD ${_HOST_EXTRA_CFLAGS} -S -o ${@} -c ${INCFLAGS} $<

assym.s: genassym.o

• $(v)sed -e '/#DEFINITION#/!d' -e 's/^.*#DEFINITION#//' -e 's/$$//' -e 'p' -e 's/#//2' -e 's/[^A-Za-z0-9_]([A-Za-z0-9_])/ \1_NUM/2' genassym.o > ${@}
  +# $(v)sed -e '/#DEFINITION#/!d' -e 's/^.*#DEFINITION#//' -e 's/$$//' -e 'p' -e 's/#//2' -e 's/[^A-Za-z0-9_]([A-Za-z0-9]_)/ \1_NUM/2' genassym.o > ${@}
• $(v)sed -e '/^[[:space:]]*DEFINITION__define_/!d;{N;s/\n//;}' -e 's/^[[:space:]]DEFINITION__define_([^:]):.ascii."[$$]([-0-9#])".$$/#define \1 \2/' -e 'p' -e 's/#//2' -e 's/^[[:space:]]#define ([A-Za-z0-9])[[:space:]][$$#]([-0-9]).*$$/#define \1_NUM \2/' genassym.o > $@

${SOBJS}: assym.s

2.7.4

[spotlightishere]

@nightsuns, can you please post the patch in a code block so I can copy/paste it? GitHub's markdown took over it 😃

[johnothwolo]

Hey @nightsuns, please paste a readable patch.

[spotlightishere]

I'm glad I got a notification from this issue. I was working with the GitHub API at the time and had the idea of just getting the raw message. I don't know how to escape backticks on Github and this patch appears to have some... so, I'll just show you how to get the raw answer.

curl -i "https://api.github.com/repos/darwin-on-arm/xnu/issues/38/comments"

It'd be under the body element in the JSON response. You'll have to replace \n with actual newlines.

[wargio]

https://github.com/wargio/xnu/commit/b17d2a5f396161467a3f9f719b76721ad6a2474b.patch

[wargio]

that's my patch

[johnothwolo]

Oh thanks @wargio, do you think it would be possible to emulate ios with this kernel?

[johnothwolo]

Somehow the kernel is still not building, I followed the instructions and the patch didn't work. The assym.s file is empty in the Build folder. I'm kinda new at this stuff....

[wargio]

try with my fork.

[johnothwolo]

It failed with the same error. I'm on macOS 10.12.6. I know enough c and I understand what the makefile template was trying to do, but i'm not fluent with unix commands. I checked the build without the patch:

sed -e '/#DEFINITION#/!d' -e 's/^.*#DEFINITION#//' -e 's/\$$//' -e 'p' -e 's/#//2' -e 's/[^A-Za-z0-9_]*\([A-Za-z0-9_]*\)/ \1_NUM/2' genassym.o >${@}

And got some definitions which were incomplete or something, but when i tried with the patch:

sed -e '/.file\s*\"#DEFINITION#/!d' -e 's/^.*#DEFINITION#//' -e 's/####\"//' -e 's/\$$//' -e 'p' -e 's/#//2' -e 's/[^A-Za-z0-9_]*\([A-Za-z0-9_]*\)/ \1_NUM/2' genassym.o > ${@}

assym.S ended up empty.