| Message ID | 1456717691-28298-6-git-send-email-nicolas.pitre@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Dne 29.2.2016 v 04:48 Nicolas Pitre napsal(a): > +# Filter out exported kernel symbol names advertised as warning pragmas > +# by the preprocessor and write them to $(1). We must consider continuation > +# lines as well: they start with a blank, or the preceeding line ends with > +# a ':'. Anything else is passed through as is. > +# See also __KSYM_DEP() in include/linux/export.h. > +ksym_dep_filter = sed -n \ > + -e '1 {x; $$!d}' \ > + -e '/^ / {H; $$!d}' \ > + -e 'x; /:$$/ {x; H; $$!d; s/^/ /; x}' \ > + -e ':filter; /^.*KBUILD_AUTOKSYM_DEP: /! {p; b next}' \ > + -e 's//KSYM_/; s/\n.*//; w $(1)' \ > + -e ':next; $$!d' \ > + -e '1 q; s/^/ /; x; /^ /! b filter' This is unreadable and it does not work with my gcc version. I get dependencies like $(wildcard include/config/ksym/simple/strtoull [enabled by default].h) \ Please use some other way, which does not require parsing the compiler diagnostic messages. A straightforward solution is to do something similar to genksyms: A separate preprocessor pass with -Dsomething that leaves the EXPORT_SYMBOL statements alone and just collect their occurences. Thanks, Michal -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, 3 Mar 2016, Michal Marek wrote: > Dne 29.2.2016 v 04:48 Nicolas Pitre napsal(a): > > +# Filter out exported kernel symbol names advertised as warning pragmas > > +# by the preprocessor and write them to $(1). We must consider continuation > > +# lines as well: they start with a blank, or the preceeding line ends with > > +# a ':'. Anything else is passed through as is. > > +# See also __KSYM_DEP() in include/linux/export.h. > > +ksym_dep_filter = sed -n \ > > + -e '1 {x; $$!d}' \ > > + -e '/^ / {H; $$!d}' \ > > + -e 'x; /:$$/ {x; H; $$!d; s/^/ /; x}' \ > > + -e ':filter; /^.*KBUILD_AUTOKSYM_DEP: /! {p; b next}' \ > > + -e 's//KSYM_/; s/\n.*//; w $(1)' \ > > + -e ':next; $$!d' \ > > + -e '1 q; s/^/ /; x; /^ /! b filter' > > This is unreadable and it does not work with my gcc version. I get > dependencies like > > $(wildcard include/config/ksym/simple/strtoull [enabled by default].h) \ That's too bad. This had almost zero overhead as the preprocessor didn't have to be executed twice. Probably adding s/ .*//; before w $(1) would fix that. But I agree this is fragile. What gcc version is this? > Please use some other way, which does not require parsing the compiler > diagnostic messages. A straightforward solution is to do something > similar to genksyms: A separate preprocessor pass with -Dsomething that > leaves the EXPORT_SYMBOL statements alone and just collect their occurences. I went that route at some point. But here I need to extract those EXPORT_SYMBOL() instances for all if_changed_dep uses. That includes cc_o_c, cc_s_c, cc_i_c, cc_lst_c, as_s_S, as_o_S, etc. etc. I need the corresponding preprocessor flags without the usual target flags. Let's see what I can do that is more readable than a sed script. Oh and who said that a sed script had to, or could be readable? ;-) Nicolas -- 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
On 2016-03-04 03:46, Nicolas Pitre wrote: > On Thu, 3 Mar 2016, Michal Marek wrote: > >> Dne 29.2.2016 v 04:48 Nicolas Pitre napsal(a): >>> +# Filter out exported kernel symbol names advertised as warning pragmas >>> +# by the preprocessor and write them to $(1). We must consider continuation >>> +# lines as well: they start with a blank, or the preceeding line ends with >>> +# a ':'. Anything else is passed through as is. >>> +# See also __KSYM_DEP() in include/linux/export.h. >>> +ksym_dep_filter = sed -n \ >>> + -e '1 {x; $$!d}' \ >>> + -e '/^ / {H; $$!d}' \ >>> + -e 'x; /:$$/ {x; H; $$!d; s/^/ /; x}' \ >>> + -e ':filter; /^.*KBUILD_AUTOKSYM_DEP: /! {p; b next}' \ >>> + -e 's//KSYM_/; s/\n.*//; w $(1)' \ >>> + -e ':next; $$!d' \ >>> + -e '1 q; s/^/ /; x; /^ /! b filter' >> >> This is unreadable and it does not work with my gcc version. I get >> dependencies like >> >> $(wildcard include/config/ksym/simple/strtoull [enabled by default].h) \ > > That's too bad. This had almost zero overhead as the preprocessor > didn't have to be executed twice. I know you are trying to collect the exports in a single pass, but parsing the compiler warnings is really fragile. > Probably adding s/ .*//; before w $(1) would fix that. But I agree this > is fragile. What gcc version is this? $ gcc --version gcc (SUSE Linux) 4.8.3 20140627 [gcc-4_8-branch revision 212064] ... The output looks like this: $ echo '_Pragma("GCC warning \"KBUILD_AUTOKSYM_DEP: test\"")' | gcc -Wall -c -xc - <stdin>:1:13: warning: KBUILD_AUTOKSYM_DEP: test [enabled by default] Clang output is similar, except that the text appears twice in the output: $ echo '_Pragma("GCC warning \"KBUILD_AUTOKSYM_DEP: test\"")' | clang -Wall -c -xc - <stdin>:1:1: warning: KBUILD_AUTOKSYM_DEP: test [-W#pragma-messages] _Pragma("GCC warning \"KBUILD_AUTOKSYM_DEP: test\"") ^ <scratch space>:2:6: note: expanded from here GCC warning "KBUILD_AUTOKSYM_DEP: test" ^ What is worse, older gccs do not support the GCC warning pragma: $ gcc --version gcc (GCC) 4.1.2 20070115 (SUSE Linux) ... $ echo '_Pragma("GCC warning \"KBUILD_AUTOKSYM_DEP: test\"")' | gcc -Wall -c -xc - <stdin>:1: warning: ignoring #pragma GCC warning > Oh and who said that a sed script had to, or could be readable? ;-) I guess I could live with a non-redable sed script embedded in a Makefile, if I knew that it won't need updating for each new compiler release :). Michal -- 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
diff --git a/include/linux/export.h b/include/linux/export.h index 77afdb2a25..794392102d 100644 --- a/include/linux/export.h +++ b/include/linux/export.h @@ -76,8 +76,20 @@ extern struct module __this_module; ___cond_export_sym(sym, sec, conf) #define ___cond_export_sym(sym, sec, enabled) \ __cond_export_sym_##enabled(sym, sec) -#define __cond_export_sym_1(sym, sec) ___EXPORT_SYMBOL(sym, sec) -#define __cond_export_sym_0(sym, sec) /* nothing */ +#define __cond_export_sym_1(sym, sec) \ + __KSYM_DEP(sym) ___EXPORT_SYMBOL(sym, sec) +#define __cond_export_sym_0(sym, sec) \ + __KSYM_DEP(sym) /* nothing */ + +/* + * For fine grained build dependencies, we want to tell the build system + * about each possible exported symbol even if they're not actually exported. + * This is accomplished with a preprocessor warning that gets captured by + * the make rule (see ksym_dep_filter in scripts/Kbuild.include). + */ +#define __KSYM_DEP(sym) __pragma_string( KBUILD_AUTOKSYM_DEP: sym ) +#define __pragma_string(x) __emit_pragma( GCC warning #x ) +#define __emit_pragma(x) _Pragma(#x) #else #define __EXPORT_SYMBOL ___EXPORT_SYMBOL diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include index 8a257fa663..0b69479310 100644 --- a/scripts/Kbuild.include +++ b/scripts/Kbuild.include @@ -258,12 +258,40 @@ if_changed_dep = $(if $(strip $(any-prereq) $(arg-check) ), \ @set -e; \ $(cmd_and_fixdep)) +ifndef CONFIG_TRIM_UNUSED_KSYMS + cmd_and_fixdep = \ $(echo-cmd) $(cmd_$(1)); \ scripts/basic/fixdep $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;\ rm -f $(depfile); \ mv -f $(dot-target).tmp $(dot-target).cmd; +else + +# Filter out exported kernel symbol names advertised as warning pragmas +# by the preprocessor and write them to $(1). We must consider continuation +# lines as well: they start with a blank, or the preceeding line ends with +# a ':'. Anything else is passed through as is. +# See also __KSYM_DEP() in include/linux/export.h. +ksym_dep_filter = sed -n \ + -e '1 {x; $$!d}' \ + -e '/^ / {H; $$!d}' \ + -e 'x; /:$$/ {x; H; $$!d; s/^/ /; x}' \ + -e ':filter; /^.*KBUILD_AUTOKSYM_DEP: /! {p; b next}' \ + -e 's//KSYM_/; s/\n.*//; w $(1)' \ + -e ':next; $$!d' \ + -e '1 q; s/^/ /; x; /^ /! b filter' + +cmd_and_fixdep = \ + $(echo-cmd) \ + $(cmd_$(1)) 2>&1 | $(call ksym_dep_filter,$(dot-target).ksym.tmp) >&2;\ + scripts/basic/fixdep -e $(depfile) $@ '$(make-cmd)' \ + < $(dot-target).ksym.tmp > $(dot-target).tmp; \ + rm -f $(dot-target).ksym.tmp $(depfile); \ + mv -f $(dot-target).tmp $(dot-target).cmd; + +endif + # Usage: $(call if_changed_rule,foo) # Will check if $(cmd_foo) or any of the prerequisites changed, # and if so will execute $(rule_foo). diff --git a/scripts/basic/fixdep.c b/scripts/basic/fixdep.c index d984deb120..2dc6bf754a 100644 --- a/scripts/basic/fixdep.c +++ b/scripts/basic/fixdep.c @@ -354,6 +354,7 @@ static void parse_dep_file(void *map, size_t len) /* Ignore certain dependencies */ if (strrcmp(s, "include/generated/autoconf.h") && + strrcmp(s, "include/generated/autoksyms.h") && strrcmp(s, "arch/um/include/uml-config.h") && strrcmp(s, "include/linux/kconfig.h") && strrcmp(s, ".ver")) {