Make sure -fcmm-sink is passed to Parser properly

Parser.hs needs to be compiled with -fcmm-sink on x86 platforms, so the
register allocator doesn't run out of stack slots. Previously, we had to
do some CPP hacks in order to emit an #ifdef into the file - this is
because we preprocess it once up front, and run the preprocessor again
when we compile it.

There's two cases: the boostrap compiler is > 7.8, and the stage1 parser
needs the flag, or the stage1 compiler is compiling the stage2
Parser.hs, and needs the flag..

The previous approach was super fragile with Clang. The more principled
fix is to instead do this through the build system.

This fixes #8182.

Signed-off-by: Austin Seipp <aseipp@pobox.com>

1 files changed, 16 insertions, 1 deletions

diff --git a/compiler/ghc.mk b/compiler/ghc.mk
index 2a7a8c4b87..1149fbdf1e 100644
--- a/compiler/ghc.mk
+++ b/compiler/ghc.mk
@@ -341,8 +341,23 @@ else
 compiler_CONFIGURE_OPTS += --ghc-option=-DNO_REGS
 endif
 
-ifeq "$(GhcProfiled)" "YES"
+# If we're bootstrapping the compiler during stage2, or we're being
+# built by a GHC whose version is > 7.8, we need -fcmm-sink to be
+# passed to the compiler. This is required on x86 to avoid the
+# register allocator running out of stack slots when compiling this
+# module with -fPIC -dynamic.
+ifeq "$(CMM_SINK_BOOTSTRAP_IS_NEEDED)" "YES"
+compiler/stage1/build/Parser_HC_OPTS += -fcmm-sink
+endif
+# However, we may be using e.g. 7.6, and thus the bootstrap compiler
+# does not need to pass -fcmm-sink, but stage1+ does!
+# We pass -fcmm-sink to every stage != 1
+# See #8182 for all the details
+compiler/stage2/build/Parser_HC_OPTS += -fcmm-sink
+compiler/stage3/build/Parser_HC_OPTS += -fcmm-sink
 
+
+ifeq "$(GhcProfiled)" "YES"
 # If we're profiling GHC then we want SCCs.  However, adding -auto-all
 # everywhere tends to give a hard-to-read profile, and adds lots of
 # overhead.  A better approach is to proceed top-down; identify the