genksyms: generate lexer and parser during build instead of shipping

Now that the kernel build supports flex and bison, remove the _shipped
files and generate them during the build instead.

There are no more shipped lexer and parser, so I ripped off the rules
in scripts/Malefile.lib that were used for REGENERATE_PARSERS.

The genksyms parser has ambiguous grammar, which would emit warnings:

 scripts/genksyms/parse.y: warning: 9 shift/reduce conflicts [-Wconflicts-sr]
 scripts/genksyms/parse.y: warning: 5 reduce/reduce conflicts [-Wconflicts-rr]

They are normally suppressed, but displayed when W=1 is given.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

scripts/Makefile.lib

@@ -184,42 +184,24 @@ endef
 quiet_cmd_flex = LEX     $@
       cmd_flex = $(LEX) -o$@ -L $<
 
-ifdef REGENERATE_PARSERS
-.PRECIOUS: $(src)/%.lex.c_shipped
-$(src)/%.lex.c_shipped: $(src)/%.l
-	$(call cmd,flex)
-endif
-
 .PRECIOUS: $(obj)/%.lex.c
-$(filter %.lex.c,$(targets)): $(obj)/%.lex.c: $(src)/%.l FORCE
+$(obj)/%.lex.c: $(src)/%.l FORCE
 	$(call if_changed,flex)
 
 # YACC
 # ---------------------------------------------------------------------------
 quiet_cmd_bison = YACC    $@
       cmd_bison = $(YACC) -o$@ -t -l $<
 
-ifdef REGENERATE_PARSERS
-.PRECIOUS: $(src)/%.tab.c_shipped
-$(src)/%.tab.c_shipped: $(src)/%.y
-	$(call cmd,bison)
-endif
-
 .PRECIOUS: $(obj)/%.tab.c
-$(filter %.tab.c,$(targets)): $(obj)/%.tab.c: $(src)/%.y FORCE
+$(obj)/%.tab.c: $(src)/%.y FORCE
 	$(call if_changed,bison)
 
 quiet_cmd_bison_h = YACC    $@
       cmd_bison_h = bison -o/dev/null --defines=$@ -t -l $<
 
-ifdef REGENERATE_PARSERS
-.PRECIOUS: $(src)/%.tab.h_shipped
-$(src)/%.tab.h_shipped: $(src)/%.y
-	$(call cmd,bison_h)
-endif
-
 .PRECIOUS: $(obj)/%.tab.h
-$(filter %.tab.h,$(targets)): $(obj)/%.tab.h: $(src)/%.y FORCE
+$(obj)/%.tab.h: $(src)/%.y FORCE
 	$(call if_changed,bison_h)
 
 # Shipped files

scripts/genksyms/Makefile

@@ -5,9 +5,36 @@ always		:= $(hostprogs-y)
 
 genksyms-objs	:= genksyms.o parse.tab.o lex.lex.o
 
+# FIXME: fix the ambiguous grammar in parse.y and delete this hack
+#
+# Suppress shift/reduce, reduce/reduce conflicts warnings
+# unless W=1 is specified.
+#
+# Just in case, run "$(YACC) --version" without suppressing stderr
+# so that 'bison: not found' will be displayed if it is missing.
+ifeq ($(findstring 1,$(KBUILD_ENABLE_EXTRA_GCC_CHECKS)),)
+
+quiet_cmd_bison_no_warn = $(quet_cmd_bison)
+      cmd_bison_no_warn = $(YACC) --version >/dev/null; \
+			  $(cmd_bison) 2>/dev/null
+
+$(obj)/parse.tab.c: $(src)/parse.y FORCE
+	$(call if_changed,bison_no_warn)
+
+quiet_cmd_bison_h_no_warn = $(quet_cmd_bison_h)
+      cmd_bison_h_no_warn = $(YACC) --version >/dev/null; \
+			    $(cmd_bison_h) 2>/dev/null
+
+$(obj)/parse.tab.h: $(src)/parse.y FORCE
+	$(call if_changed,bison_h_no_warn)
+
+endif
+
 # -I needed for generated C source (shipped source)
 HOSTCFLAGS_parse.tab.o := -I$(src)
 HOSTCFLAGS_lex.lex.o := -I$(src)
 
 # dependencies on generated files need to be listed explicitly
 $(obj)/lex.lex.o: $(obj)/parse.tab.h
+
+targets := lex.lex.c parse.tab.c parse.tab.h