From b3199f6977fdaed6f3f898aee14bd0af61140cf5 Mon Sep 17 00:00:00 2001
From: "Edward Z. Yang" <ezyang@mit.edu>
Date: Mon, 4 Apr 2011 12:56:00 +0100
Subject: [PATCH] Flag for defaulting the codegen GhcStageXDefaultNewCodegen.

Signed-off-by: Edward Z. Yang <ezyang@mit.edu>
---
 compiler/ghc.mk           |   12 ++++++++++++
 compiler/main/DynFlags.hs |    4 ++++
 mk/config.mk.in           |   10 ++++++++++
 3 files changed, 26 insertions(+)

diff --git a/compiler/ghc.mk b/compiler/ghc.mk
index 357b51c..48a802a 100644
--- a/compiler/ghc.mk
+++ b/compiler/ghc.mk
@@ -491,6 +491,18 @@ compiler_stage1_HC_OPTS += $(GhcStage1HcOpts)
 compiler_stage2_HC_OPTS += $(GhcStage2HcOpts)
 compiler_stage3_HC_OPTS += $(GhcStage3HcOpts)
 
+ifeq "$(GhcStage1DefaultNewCodegen)" "YES"
+compiler_stage1_HC_OPTS += -DGHC_DEFAULT_NEW_CODEGEN
+endif
+
+ifeq "$(GhcStage2DefaultNewCodegen)" "YES"
+compiler_stage2_HC_OPTS += -DGHC_DEFAULT_NEW_CODEGEN
+endif
+
+ifeq "$(GhcStage3DefaultNewCodegen)" "YES"
+compiler_stage3_HC_OPTS += -DGHC_DEFAULT_NEW_CODEGEN
+endif
+
 ifneq "$(BINDIST)" "YES"
 
 compiler_stage2_TAGS_HC_OPTS = -package ghc
diff --git a/compiler/main/DynFlags.hs b/compiler/main/DynFlags.hs
index c7a7b02..9f504a1 100644
--- a/compiler/main/DynFlags.hs
+++ b/compiler/main/DynFlags.hs
@@ -1646,6 +1646,10 @@ defaultFlags
 
       Opt_SharedImplib,
 
+#if GHC_DEFAULT_NEW_CODEGEN
+      Opt_TryNewCodeGen,
+#endif
+
       Opt_GenManifest,
       Opt_EmbedManifest,
       Opt_PrintBindContents,
diff --git a/mk/config.mk.in b/mk/config.mk.in
index e5b6811..10911e6 100644
--- a/mk/config.mk.in
+++ b/mk/config.mk.in
@@ -97,6 +97,16 @@ GhcStage1HcOpts=
 GhcStage2HcOpts=-O2
 GhcStage3HcOpts=-O2
 
+# These options modify whether or not a built compiler for a bootstrap
+# stage defaults to using the new code generation path.  The new
+# code generation path is a bit slower, so for development just
+# GhcStage2DefaultNewCodegen=YES, but it's also a good idea to try
+# building all libraries and the stage2 compiler with the
+# new code generator, which involves GhcStage1DefaultNewCodegen=YES.
+GhcStage1DefaultNewCodegen=NO
+GhcStage2DefaultNewCodegen=NO
+GhcStage3DefaultNewCodegen=NO
+
 GhcDebugged=NO
 GhcDynamic=NO
 
-- 
1.7.10.4