the gcc optimizer frequently finds broken code (use of uninitalized variables, unreachable code, etc.), which is good. however, developers usually compile with the optimizer turned off, because if they need to debug the resulting code, optimized code makes that process very difficult. this means that we get code changes committed that weren't adequately checked over for these sorts of problems.

with this build system change, if (and only if) --enable-dev-mode was used and DONT_OPTIMIZE is turned on, when a source file is compiled it will actually be preprocessed (into a .i or .ii file), then compiled once with optimization (with the result sent to /dev/null) and again without optimization (but only if the first compile succeeded, of course).

while making these changes, i did some cleanup work in Makefile.rules to move commonly-used combinations of flag variables into their own variables, to make the file easier to read and maintain



git-svn-id: http://svn.digium.com/svn/asterisk/branches/1.4@157859 f38db490-d61c-443f-a65b-d21fe96a405b

1 files changed, 75 insertions, 24 deletions

diff --git a/Makefile.rules b/Makefile.rules
index 2d66c7a3e..387420f32 100644
--- a/Makefile.rules
+++ b/Makefile.rules
@@ -3,7 +3,7 @@
 # 
 # Makefile rules
 #
-# Copyright (C) 2006, Digium, Inc.
+# Copyright (C) 2006-2008, Digium, Inc.
 #
 # Kevin P. Fleming <kpfleming@digium.com>
 #
@@ -19,44 +19,95 @@
 
 .PHONY: dist-clean
 
+# extra cflags to build dependencies. Recursively expanded.
+MAKE_DEPS=-MD -MT $@ -MF .$(subst /,_,$@).d -MP
+
 ifeq ($(NOISY_BUILD),)
-   ECHO_PREFIX=@
-   CMD_PREFIX=@
+    ECHO_PREFIX=@
+    CMD_PREFIX=@
 else
-   ECHO_PREFIX=@\# 
-   CMD_PREFIX=
+    ECHO_PREFIX=@\# 
+    CMD_PREFIX=
 endif
 
+OPTIMIZE?=-O6
+
 ifeq ($(findstring DONT_OPTIMIZE,$(MENUSELECT_CFLAGS)),)
-# More GSM codec optimization
-# Uncomment to enable MMXTM optimizations for x86 architecture CPU's
-# which support MMX instructions.  This should be newer pentiums,
-# ppro's, etc, as well as the AMD K6 and K7.  
-#K6OPT=-DK6OPT
+    # More GSM codec optimization
+    # Uncomment to enable MMXTM optimizations for x86 architecture CPU's
+    # which support MMX instructions.  This should be newer pentiums,
+    # ppro's, etc, as well as the AMD K6 and K7.  
+    #K6OPT=-DK6OPT
 
-OPTIMIZE?=-O6
-ASTCFLAGS+=$(OPTIMIZE)
+    ASTCFLAGS+=$(OPTIMIZE)
 endif
 
-%.o: %.c
-	$(ECHO_PREFIX) echo "   [CC] $< -> $@"
-	$(CMD_PREFIX) $(CC) -o $@ -c $< $(PTHREAD_CFLAGS) $(ASTCFLAGS) -MD -MT $@ -MF .$(subst /,_,$@).d -MP
+# shortcuts for common combinations of flags; these must be recursively expanded so that
+# per-target settings will be applied
+CC_CFLAGS=$(PTHREAD_CFLAGS) $(ASTCFLAGS)
+CXX_CFLAGS=$(PTHREAD_CFLAGS) $(filter-out -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations $(AST_DECLARATION_AFTER_STATEMENT),$(ASTCFLAGS))
+CC_LDFLAGS_SO=$(PTHREAD_CFLAGS) $(ASTLDFLAGS) $(SOLINK)
+CXX_LDFLAGS_SO=$(PTHREAD_CFLAGS) $(ASTLDFLAGS) $(SOLINK)
+CC_LIBS=$(PTHREAD_LIBS) $(LIBS)
+CXX_LIBS=$(PTHREAD_LIBS) $(LIBS)
+
+# determine whether to double-compile so that the optimizer can report code path problems
+# this is only done when developer mode and DONT_OPTIMIZE are both enabled
+# in that case, we run the preprocessor to produce a .i or .ii file from the source
+# code, then compile once with optimizer enabled (and the output to /dev/null),
+# and if that doesn't fail then compile again with optimizer disabled
+ifeq ($(findstring DONT_OPTIMIZE,$(MENUSELECT_CFLAGS))$(AST_DEVMODE),DONT_OPTIMIZEyes)
+COMPILE_DOUBLE=yes
+endif
+
+%.o: %.s
+	$(ECHO_PREFIX) echo "   [AS] $< -> $@"
+ifeq ($(COMPILE_DOUBLE),yes)
+	$(CMD_PREFIX) $(CC) -o /dev/null -c $< $(CC_CFLAGS) $(OPTIMIZE)
+endif
+	$(CMD_PREFIX) $(CC) -o $@ -c $< $(CC_CFLAGS)
 
 %.o: %.i
 	$(ECHO_PREFIX) echo "   [CCi] $< -> $@"
-	$(CMD_PREFIX) $(CC) -o $@ -c $< $(PTHREAD_CFLAGS) $(ASTCFLAGS) -MD -MT $@ -MF .$(subst /,_,$@).d -MP
+ifeq ($(COMPILE_DOUBLE),yes)
+	$(CMD_PREFIX) $(CC) -o /dev/null -c $< $(CC_CFLAGS) $(OPTIMIZE)
+endif
+	$(CMD_PREFIX) $(CC) -o $@ -c $< $(CC_CFLAGS)
+
+%.o: %.c
+	$(ECHO_PREFIX) echo "   [CC] $< -> $@"
+ifeq ($(COMPILE_DOUBLE),yes)
+	$(CMD_PREFIX) $(CC) -o $(@:%.o=%.i) -E $< $(CC_CFLAGS) $(MAKE_DEPS)
+	$(CMD_PREFIX) $(CC) -o /dev/null -c $(@:%.o=%.i) $(CC_CFLAGS) $(OPTIMIZE)
+	$(CMD_PREFIX) $(CC) -o $@ -c $(@:%.o=%.i) $(CC_CFLAGS)
+else
+	$(CMD_PREFIX) $(CC) -o $@ -c $< $(CC_CFLAGS) $(MAKE_DEPS)
+endif
 
 %.i: %.c
 	$(ECHO_PREFIX) echo "   [CPP] $< -> $@"
-	$(CMD_PREFIX) $(CC) -o $@ -E $< $(PTHREAD_CFLAGS) $(ASTCFLAGS) -MD -MT $@ -MF .$(subst /,_,$@).d -MP
+	$(CMD_PREFIX) $(CC) -o $@ -E $< $(CC_CFLAGS) $(MAKE_DEPS)
 
-%.o: %.s
-	$(ECHO_PREFIX) echo "   [AS] $< -> $@"
-	$(CMD_PREFIX) $(CC) -o $@ -c $< $(PTHREAD_CFLAGS) $(ASTCFLAGS) -MD -MT $@ -MF .$(subst /,_,$@).d -MP
+%.oo: %.ii
+	$(ECHO_PREFIX) echo "   [CXXi] $< -> $@"
+ifeq ($(COMPILE_DOUBLE),yes)
+	$(CMD_PREFIX) $(CXX) -o /dev/null -c $< $(CXX_CFLAGS) $(OPTIMIZE)
+endif
+	$(CMD_PREFIX) $(CXX) -o $@ -c $< $(CXX_CFLAGS)
 
 %.oo: %.cc
 	$(ECHO_PREFIX) echo "   [CXX] $< -> $@"
-	$(CMD_PREFIX) $(CXX) -o $@ -c $< $(PTHREAD_CFLAGS) $(filter-out -Wstrict-prototypes -Wmissing-prototypes -Wmissing-declarations $(AST_DECLARATION_AFTER_STATEMENT),$(ASTCFLAGS)) -MD -MT $@ -MF .$(subst /,_,$@).d -MP
+ifeq ($(COMPILE_DOUBLE),yes)
+	$(CMD_PREFIX) $(CXX) -o $(@:%.oo=%.ii) -E $< $(CXX_CFLAGS) $(MAKE_DEPS)
+	$(CMD_PREFIX) $(CXX) -o /dev/null -c $(@:%.oo=%.ii) $(CXX_CFLAGS) $(MAKE_DEPS) $(OPTIMIZE)
+	$(CMD_PREFIX) $(CXX) -o $@ -c $(@:%.oo=%.ii) $(CXX_CFLAGS) $(MAKE_DEPS)
+else
+	$(CMD_PREFIX) $(CXX) -o $@ -c $< $(CXX_CFLAGS) $(MAKE_DEPS)
+endif
+
+%.ii: %.cc
+	$(ECHO_PREFIX) echo "   [CPP] $< -> $@"
+	$(CMD_PREFIX) $(CXX) -o $@ -E $< $(CXX_CFLAGS) $(MAKE_DEPS)
 
 %.c: %.y
 	$(ECHO_PREFIX) echo "   [BISON] $< -> $@"
@@ -68,14 +119,14 @@ endif
 
 %.so: %.o
 	$(ECHO_PREFIX) echo "   [LD] $^ -> $@"
-	$(CMD_PREFIX) $(CC) $(STATIC_BUILD) -o $@ $(PTHREAD_CFLAGS) $(ASTLDFLAGS) $(SOLINK) $^ $(PTHREAD_LIBS) $(LIBS)
+	$(CMD_PREFIX) $(CC) $(STATIC_BUILD) -o $@ $(CC_LDFLAGS_SO) $^ $(CC_LIBS)
 
 %.so: %.oo
 	$(ECHO_PREFIX) echo "   [LDXX] $^ -> $@"
-	$(CMD_PREFIX) $(CXX) $(STATIC_BUILD) -o $@ $(PTHREAD_CFLAGS) $(ASTLDFLAGS) $(SOLINK) $^ $(PTHREAD_LIBS) $(LIBS)
+	$(CMD_PREFIX) $(CXX) $(STATIC_BUILD) -o $@ $(CXX_LDFLAGS_SO) $^ $(CXX_LIBS)
 
 %: %.o
 	$(ECHO_PREFIX) echo "   [LD] $^ -> $@"
-	$(CMD_PREFIX) $(CXX) $(STATIC_BUILD) -o $@ $(PTHREAD_CFLAGS) $(ASTLDFLAGS) $^ $(PTHREAD_LIBS) $(LIBS)
+	$(CMD_PREFIX) $(CXX) $(STATIC_BUILD) -o $@ $(PTHREAD_CFLAGS) $(ASTLDFLAGS) $^ $(CXX_LIBS)
 
 dist-clean:: clean