Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild

Pull kbuild updates from Michal Marek:

 - new option CONFIG_TRIM_UNUSED_KSYMS which does a two-pass build and
   unexports symbols which are not used in the current config [Nicolas
   Pitre]

 - several kbuild rule cleanups [Masahiro Yamada]

 - warning option adjustments for gcov etc [Arnd Bergmann]

 - a few more small fixes

* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: (31 commits)
  kbuild: move -Wunused-const-variable to W=1 warning level
  kbuild: fix if_change and friends to consider argument order
  kbuild: fix adjust_autoksyms.sh for modules that need only one symbol
  kbuild: fix ksym_dep_filter when multiple EXPORT_SYMBOL() on the same line
  gcov: disable -Wmaybe-uninitialized warning
  gcov: disable tree-loop-im to reduce stack usage
  gcov: disable for COMPILE_TEST
  Kbuild: disable 'maybe-uninitialized' warning for CONFIG_PROFILE_ALL_BRANCHES
  Kbuild: change CC_OPTIMIZE_FOR_SIZE definition
  kbuild: forbid kernel directory to contain spaces and colons
  kbuild: adjust ksym_dep_filter for some cmd_* renames
  kbuild: Fix dependencies for final vmlinux link
  kbuild: better abstract vmlinux sequential prerequisites
  kbuild: fix call to adjust_autoksyms.sh when output directory specified
  kbuild: Get rid of KBUILD_STR
  kbuild: rename cmd_as_s_S to cmd_cpp_s_S
  kbuild: rename cmd_cc_i_c to cmd_cpp_i_c
  kbuild: drop redundant "PHONY += FORCE"
  kbuild: delete unnecessary "@:"
  kbuild: mark help target as PHONY
  ...

1 files changed, 31 insertions, 2 deletions

diff --git a/include/linux/export.h b/include/linux/export.h
index 96e45ea463e7..2f9ccbe6a639 100644
--- a/include/linux/export.h
+++ b/include/linux/export.h
@@ -38,7 +38,7 @@ extern struct module __this_module;
 
 #ifdef CONFIG_MODULES
 
-#ifndef __GENKSYMS__
+#if defined(__KERNEL__) && !defined(__GENKSYMS__)
 #ifdef CONFIG_MODVERSIONS
 /* Mark the CRC weak since genksyms apparently decides not to
  * generate a checksums for some symbols */
@@ -53,7 +53,7 @@ extern struct module __this_module;
 #endif
 
 /* For every exported symbol, place a struct in the __ksymtab section */
-#define __EXPORT_SYMBOL(sym, sec)				\
+#define ___EXPORT_SYMBOL(sym, sec)				\
 	extern typeof(sym) sym;					\
 	__CRC_SYMBOL(sym, sec)					\
 	static const char __kstrtab_##sym[]			\
@@ -65,6 +65,35 @@ extern struct module __this_module;
 	__attribute__((section("___ksymtab" sec "+" #sym), unused))	\
 	= { (unsigned long)&sym, __kstrtab_##sym }
 
+#if defined(__KSYM_DEPS__)
+
+/*
+ * For fine grained build dependencies, we want to tell the build system
+ * about each possible exported symbol even if they're not actually exported.
+ * We use a string pattern that is unlikely to be valid code that the build
+ * system filters out from the preprocessor output (see ksym_dep_filter
+ * in scripts/Kbuild.include).
+ */
+#define __EXPORT_SYMBOL(sym, sec)	=== __KSYM_##sym ===
+
+#elif defined(CONFIG_TRIM_UNUSED_KSYMS)
+
+#include <linux/kconfig.h>
+#include <generated/autoksyms.h>
+
+#define __EXPORT_SYMBOL(sym, sec)				\
+	__cond_export_sym(sym, sec, config_enabled(__KSYM_##sym))
+#define __cond_export_sym(sym, sec, conf)			\
+	___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 */
+
+#else
+#define __EXPORT_SYMBOL ___EXPORT_SYMBOL
+#endif
+
 #define EXPORT_SYMBOL(sym)					\
 	__EXPORT_SYMBOL(sym, "")