From 28c8dda7c67ba4e3766b28acec4b0f40738ec139 Mon Sep 17 00:00:00 2001
From: Christophe de Dinechin <dinechin@redhat.com>
Date: Mon, 1 May 2017 17:06:28 +0200
Subject: [PATCH] Single-pass dependency generation

---
 config.gnu.mk   | 13 +++++++------
 config.mingw.mk |  5 -----
 rules.mk        | 19 +++++++------------
 3 files changed, 14 insertions(+), 23 deletions(-)

diff --git a/config.gnu.mk b/config.gnu.mk
index 9df9147..a1e3592 100644
--- a/config.gnu.mk
+++ b/config.gnu.mk
@@ -46,7 +46,7 @@ CFLAGS_profile=	-pg
 CFLAGS_cxx=     -x c++
 LDFLAGS_debug=  -g
 LDFLAGS_profile=-pg
-
+DEPFLAGS=	-MD -MP -MF $(@).d -MT $@
 
 #------------------------------------------------------------------------------
 #  File extensions
@@ -62,8 +62,9 @@ DLL_EXT=        .so
 #  Build rules
 #------------------------------------------------------------------------------
 
-MAKE_CC=        $(CC)   $(CFLAGS)   $(CPPFLAGS_$*) $(CFLAGS_$*)   -c $< -o $@
-MAKE_CXX=       $(CXX)  $(CXXFLAGS) $(CPPFLAGS_$*) $(CXXFLAGS_$*) -c $< -o $@
+MAKE_CC=        $(CC)   $(CFLAGS)   $(CPPFLAGS_$*) $(CFLAGS_$*)   -c $< -o $@ $(DEPFLAGS)
+MAKE_CXX=       $(CXX)  $(CXXFLAGS) $(CPPFLAGS_$*) $(CXXFLAGS_$*) -c $< -o $@ $(DEPFLAGS)
+MAKE_AS=        $(CC)   $(CFLAGS)   $(CPPFLAGS_$*) $(CFLAGS_$*)   -c $< -o $@ $(DEPFLAGS)
 MAKE_OBJDIR=    mkdir -p $*                                       && touch $@
 MAKE_LIB=       $(AR) $@                        $(LINK_INPUTS)&& $(RANLIB) $@
 MAKE_DLL=       $(LIBTOOL) -shared              $(LINK_INPUTS)          -o $@
@@ -74,6 +75,6 @@ MAKE_EXE=       $(LD) -o $@ $(LINK_INPUTS) $(LDFLAGS) $(LDFLAGS_$*)
 #   Dependencies
 #------------------------------------------------------------------------------
 
-CC_DEPEND=      $(CC)  $(CPPFLAGS) $(CPPFLAGS_$*) -MM -MF $@ -MT $(@:.d=) $<
-CXX_DEPEND=     $(CXX) $(CPPFLAGS) $(CPPFLAGS_$*) -MM -MF $@ -MT $(@:.d=) $<
-AS_DEPEND=      $(CC)  $(CPPFLAGS) $(CPPFLAGS_$*) -MM -MF $@ -MT $(@:.d=) $<
+CC_DEPEND=      $(CC)  $(CPPFLAGS) $(CPPFLAGS_$*) -MM -MP -MF $@ -MT $(@:.d=) $<
+CXX_DEPEND=     $(CXX) $(CPPFLAGS) $(CPPFLAGS_$*) -MM -MP -MF $@ -MT $(@:.d=) $<
+AS_DEPEND=      $(CC)  $(CPPFLAGS) $(CPPFLAGS_$*) -MM -MP -MF $@ -MT $(@:.d=) $<
diff --git a/config.mingw.mk b/config.mingw.mk
index 4a396de..c2b6b08 100644
--- a/config.mingw.mk
+++ b/config.mingw.mk
@@ -28,11 +28,6 @@ OS_NAME_mingw=windows
 
 include $(BUILD)config.gnu.mk
 
-# We need a special treatment of this on Windows
-POSTPROCESS_DEPENDENCY=                             		\
-    ( sed -e 's/.*://' -e 's/\\$$//' < $@ |         		\
-      sed -e 's/^ *//' -e 's/$$/:/' -e 's/\\\\:$$/:/' >> $@ )
-
 # MinGW does not have --line-buffered for colorized builds
 LINE_BUFFERED=
 
diff --git a/rules.mk b/rules.mk
index 34f806a..4e22029 100644
--- a/rules.mk
+++ b/rules.mk
@@ -314,21 +314,16 @@ OBJDIR_DEPS=$(OBJDIR)/%.deps/.mkdir
 
 OBJ_DEPS=$(OBJDIR_DEPS) $(MAKEFILE_DEPS) | hello prebuild
 
-# The following is a trick to avoid errors if a header file appears in a
-# generated dependency but no longer in the source code.
-# The trick is quite ugly, but fortunately documented here:
-# http://scottmcpeak.com/autodepend/autodepend.html
-POSTPROCESS_DEPENDENCY?=                            \
-    ( sed -e 's/.*://' -e 's/\\$$//' < $@ |         \
-      fmt -1 |                                      \
-      sed -e 's/^ *//' -e 's/$$/:/' >> $@ )
-
+ifndef DEPFLAGS
 $(OBJDIR)/%.c$(OBJ_EXT).d:		%.c		$(OBJ_DEPS)
-	$(PRINT_DEPEND) ( $(CC_DEPEND)  && $(POSTPROCESS_DEPENDENCY) )
+	$(PRINT_DEPEND) ( $(CC_DEPEND)
 $(OBJDIR)/%.cpp$(OBJ_EXT).d:	%.cpp	$(OBJ_DEPS)
-	$(PRINT_DEPEND) ( $(CXX_DEPEND) && $(POSTPROCESS_DEPENDENCY) )
+	$(PRINT_DEPEND) ( $(CXX_DEPEND)
 $(OBJDIR)/%.s$(OBJ_EXT).d: 		%.s		$(OBJ_DEPS)
-	$(PRINT_DEPEND) ( $(AS_DEPEND)  && $(POSTPROCESS_DEPENDENCY) )
+	$(PRINT_DEPEND) ( $(AS_DEPEND)
+else
+$(OBJDIR)/%$(OBJ_EXT).d: $(OBJDIR)/%$(OBJ_EXT)
+endif
 
 
 #------------------------------------------------------------------------------