Bug Fixes:

* Ensure that BUILT_SOURCES depends on OBJ_DIR/Makefile so that they do not
  get built before the Makefile is updated.
* Fix build script for yacc & lex files by stopping it from thwarting the
  dependencies on the file. If the .y file changes, it needs to be rebuilt.
  This also cleans up the problem with llvmAsmParser ALWAYS rebuilding its
  Yacc files just to throw them away because there's no change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17288 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/Makefile.rules b/Makefile.rules
index a6cb6bb..4a2549a 100644
--- a/Makefile.rules
+++ b/Makefile.rules
@@ -61,7 +61,7 @@
 # PRECONDITIONS: that which must be built/checked first
 ################################################################################
 
-SRCMKFILES    := $(filter-out Makefile.rules %.in,\
+SRCMKFILES    := $(BUILD_SRC_DIR)/Makefile $(filter-out Makefile.rules %.in,\
                  $(wildcard $(BUILD_SRC_DIR)/Makefile.*))
 OBJMKFILES    := $(subst $(BUILD_SRC_DIR),$(BUILD_OBJ_DIR),$(SRCMKFILES))
 CONFIGURE     := $(LLVM_SRC_ROOT)/configure
@@ -82,6 +82,8 @@
 	$(VERB) $(RM) -f $(BUILT_SOURCES)
 endif
 
+$(BUILT_SOURCES) : $(BUILD_OBJ_ROOT)/Makefile
+
 #------------------------------------------------------------------------
 # Make sure we're not using a stale configuration
 #------------------------------------------------------------------------
@@ -806,21 +808,17 @@
 	$(SED) 's/void yyunput/inline void yyunput/' | \
 	$(SED) 's/void \*yy_flex_realloc/inline void *yy_flex_realloc/' | \
 	$(SED) 's/#define YY_BUF_SIZE 16384/#define YY_BUF_SIZE (16384*64)/' \
-	  > $@.tmp
-	$(VERB) cmp -s $@ $@.tmp > /dev/null || $(MV) -f $@.tmp $@
-	@# remove the output of flex if it didn't get moved over...
-	@rm -f $@.tmp
+	  > $@
 
 # Rule for building the bison parsers...
 %.c: %.y     # Cancel built-in rules for yacc
+%.cpp: %.y   # Cancel built-in rules for yacc
 %.h: %.y     # Cancel built-in rules for yacc
 %.cpp %.h : %.y
 	@$(ECHO) "Bisoning $*.y"
 	$(VERB) $(BISON) -v -d -p $(<F:%Parser.y=%) -o $*.tab.c  $<
-	$(VERB) cmp -s $*.tab.c $*.cpp > /dev/null || $(MV) -f $*.tab.c $*.cpp
-	$(VERB) cmp -s $*.tab.h $*.h   > /dev/null || $(MV) -f $*.tab.h $*.h
-	@# If the files were not updated, don't leave them lying around...
-	@rm -f $*.tab.c $*.tab.h
+	$(VERB) $(MV) -f $*.tab.c $*.cpp
+	$(VERB) $(MV) -f $*.tab.h $*.h
 
 # To create the directories...
 %/.dir: