kbuild: remove unnecessary in-subshell execution

[linux.git] / scripts / Makefile.build

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index fd03d60f6c5aca50f94131f2d500cbcc4325c352..f8e2794107edefa9034c867c6d00f6d69ae31edc 100644 (file)
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -312,11 +312,11 @@ $(real-obj-m:.o=.s): modkern_aflags := $(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE)
 #
 # These mirror gensymtypes_c and co above, keep them in synch.
 cmd_gensymtypes_S =                                                         \
-    (echo "\#include <linux/kernel.h>" ;                                    \
+   { echo "\#include <linux/kernel.h>" ;                                    \
      echo "\#include <asm/asm-prototypes.h>" ;                              \
     $(CPP) $(a_flags) $< |                                                  \
      grep "\<___EXPORT_SYMBOL\>" |                                          \
-     sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ) | \
+     sed 's/.*___EXPORT_SYMBOL[[:space:]]*\([a-zA-Z0-9_]*\)[[:space:]]*,.*/EXPORT_SYMBOL(\1);/' ; } | \
     $(CPP) -D__GENKSYMS__ $(c_flags) -xc - |                                \
     $(GENKSYMS) $(if $(1), -T $(2))                                         \
      $(patsubst y,-R,$(CONFIG_MODULE_REL_CRCS))                             \
@@ -394,17 +394,12 @@ $(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
 $(sort $(subdir-obj-y)): $(subdir-ym) ;
 
 #
-# Rule to compile a set of .o files into one .o file
+# Rule to compile a set of .o files into one .a file (without symbol table)
 #
 ifdef builtin-target
 
-# built-in.a archives are made with no symbol table or index which
-# makes them small and fast, but unable to be used by the linker.
-# scripts/link-vmlinux.sh builds an aggregate built-in.a with a symbol
-# table and index.
 quiet_cmd_ar_builtin = AR      $@
-      cmd_ar_builtin = rm -f $@; \
-                     $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(filter $(real-obj-y), $^)
+      cmd_ar_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(real-prereqs)
 
 $(builtin-target): $(real-obj-y) FORCE
        $(call if_changed,ar_builtin)
@@ -426,13 +421,13 @@ $(modorder-target): $(subdir-ym) FORCE
        $(Q)(cat /dev/null; $(modorder-cmds)) > $@
 
 #
-# Rule to compile a set of .o files into one .a file
+# Rule to compile a set of .o files into one .a file (with symbol table)
 #
 ifdef lib-target
 quiet_cmd_link_l_target = AR      $@
 
 # lib target archives do get a symbol table and index
-cmd_link_l_target = rm -f $@; $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(lib-y)
+cmd_link_l_target = rm -f $@; $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(real-prereqs)
 
 $(lib-target): $(lib-y) FORCE
        $(call if_changed,link_l_target)
@@ -457,6 +452,10 @@ targets += $(obj)/lib-ksyms.o
 
 endif
 
+# NOTE:
+# Do not replace $(filter %.o,^) with $(real-prereqs). When a single object
+# module is turned into a multi object module, $^ will contain header file
+# dependencies recorded in the .*.cmd file.
 quiet_cmd_link_multi-m = LD [M]  $@
 cmd_link_multi-m = $(LD) $(ld_flags) -r -o $@ $(filter %.o,$^) $(cmd_secanalysis)