From ecad2dfb109571c2b91760891f2cf62b53a1cdc6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Villemot?= <sebastien@dynare.org>
Date: Wed, 14 Aug 2019 11:21:47 +0200
Subject: [PATCH] Avoid running bison and flex multiple times when doing
 parallel builds

---
 src/Makefile.am       | 12 +++++++++---
 src/macro/Makefile.am |  8 ++++++--
 2 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/src/Makefile.am b/src/Makefile.am
index aced0535..b594a830 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -68,14 +68,20 @@ dynare_m_CPPFLAGS = $(BOOST_CPPFLAGS) -I.
 dynare_m_LDFLAGS = $(AM_LDFLAGS) $(BOOST_LDFLAGS)
 dynare_m_LDADD = macro/libmacro.a $(BOOST_FILESYSTEM_LIB) $(BOOST_SYSTEM_LIB)
 
-DynareFlex.cc FlexLexer.h: DynareFlex.ll
+DynareFlex.cc: DynareFlex.ll
 	$(LEX) -o DynareFlex.cc DynareFlex.ll
+
+FlexLexer.h:
 	cp $(LEXINC)/FlexLexer.h . || test -f ./FlexLexer.h
 
 dynare_m-DynareFlex.$(OBJEXT): CXXFLAGS += -Wno-old-style-cast
 
-DynareBison.cc DynareBison.hh location.hh stack.hh position.hh: DynareBison.yy
-	$(YACC) -W -o DynareBison.cc DynareBison.yy
+# We do not use a multiple target rule for Bison, because otherwise it will be
+# run several times in parallel builds
+DynareBison.cc: DynareBison.yy
+	$(YACC) -W -o $@ $<
+
+DynareBison.hh location.hh stack.hh position.hh: DynareBison.cc
 
 all-local: $(PROGRAMS)
 
diff --git a/src/macro/Makefile.am b/src/macro/Makefile.am
index a23480b0..c97e99fc 100644
--- a/src/macro/Makefile.am
+++ b/src/macro/Makefile.am
@@ -26,5 +26,9 @@ Tokenizer.cc: Tokenizer.ll
 
 libmacro_a-Tokenizer.$(OBJEXT): CXXFLAGS += -Wno-old-style-cast
 
-Parser.cc Parser.hh location.hh stack.hh position.hh: Parser.yy
-	$(YACC) -W -o Parser.cc Parser.yy
+# We do not use a multiple target rule for Bison, because otherwise it will be
+# run several times in parallel builds
+Parser.cc: Parser.yy
+	$(YACC) -W -o $@ $<
+
+Parser.hh location.hh stack.hh position.hh: Parser.cc