Split CONFIG_DEBUG from CONFIG_DEBUG_PESSIMIZE, and consolidate some Rules.mak

stuff along the way.

2 files changed, 31 insertions, 13 deletions

diff --git a/Config.in b/Config.in
index 6dd4c58e7..bdc4b0a4f 100644
--- a/Config.in
+++ b/Config.in
@@ -288,17 +288,27 @@ endmenu
 menu 'Debugging Options'
 
 config CONFIG_DEBUG
-        bool "Build BusyBox with Debugging symbols"
+        bool "Build BusyBox with extra Debugging symbols"
         default n
         help
-          Say Y here if you wish to compile BusyBox with debugging symbols.
-          This will allow you to use a debugger to examine BusyBox internals
-          while applets are running.  This increases the size of the binary
-          considerably and should only be used when doing development.
-          If you are doing development and want to debug BusyBox, answer Y.
+          Say Y here if you wish to examine BusyBox internals while applets are
+          running.  This increases the size of the binary considerably, and
+          should only be used when doing development.  If you are doing
+          development and want to debug BusyBox, answer Y.
 
           Most people should answer N.
 
+config CONFIG_DEBUG_PESSIMIZE
+        bool "Disable compiler optimizations."
+        default n
+        depends on CONFIG_DEBUG
+        help
+          The compiler's optimization of source code can eliminate and reorder
+          code, resulting in an executable that's hard to understand when
+          stepping through it with a debugger.  This switches it off, resulting
+          in a much bigger executable that more closely matches the source
+          code.
+
 choice
         prompt "Additional debugging library"
         default CONFIG_NO_DEBUG_LIB
diff --git a/Rules.mak b/Rules.mak
index 605cce3c2..53dd6a857 100644
--- a/Rules.mak
+++ b/Rules.mak
@@ -75,13 +75,14 @@ CFLAGS_EXTRA=$(subst ",, $(strip $(EXTRA_CFLAGS_OPTIONS)))
 
 # This must bind late because srcdir is reset for every source subdirectory.
 INCS:=-I$(top_builddir)/include -I$(top_srcdir)/include
-CFLAGS=$(INCS) -I$(srcdir)
+CFLAGS=$(INCS) -I$(srcdir) -D_GNU_SOURCE
 CFLAGS+=$(CHECKED_CFLAGS)
 ARFLAGS=cru
 
 # Warnings
 
-CFLAGS+=-Wall -Wstrict-prototypes -Wshadow
+CFLAGS += -Wall -Wstrict-prototypes -Wshadow
+LDFLAGS += $(call check_ld,--warn-common,)
 
 # gcc centric. Perhaps fiddle with findstring gcc,$(CC) for the rest
 # get the CC MAJOR/MINOR version
@@ -183,7 +184,7 @@ ifeq ($(strip $(shell [ $(CC_MAJOR) -ge 4 -a $(CC_MINOR) -ge 1 ] ; echo $$?)),0)
         OPTIMIZATION+=$(call check_gcc,-fno-branch-count-reg,)
 endif # gcc-4.1 and beyond
 endif
-OPTIMIZATIONS:=$(OPTIMIZATION) $(call check_gcc,-fomit-frame-pointer,)
+OPTIMIZATION+=$(call check_gcc,-fomit-frame-pointer,)
 
 #
 #--------------------------------------------------------
@@ -207,14 +208,21 @@ else
         LIBRARIES:=-lefence
     endif
 endif
+
+# Debugging info
+
 ifeq ($(strip $(CONFIG_DEBUG)),y)
-    CFLAGS  +=-g -D_GNU_SOURCE
-    LDFLAGS += $(call check_ld,--warn-common,)
+    CFLAGS +=-g
 else
-    CFLAGS+=$(OPTIMIZATIONS) -D_GNU_SOURCE -DNDEBUG
-    LDFLAGS += $(call check_ld,--warn-common,)
+    CFLAGS +=-DNDEBUG
     LDFLAGS += $(call check_ld,--sort-common,)
 endif
+
+ifneq ($(strip $(CONFIG_DEBUG_PESSIMIZE)),y)
+else
+    CFLAGS += $(OPTIMIZATION)
+endif
+
 # warn a bit more verbosely for non-release versions
 ifneq ($(EXTRAVERSION),)
     CHECKED_CFLAGS+=$(call check_gcc,-Wstrict-prototypes,)