From ee530105908be22c530fe44ddce5b4d733a26b8b Mon Sep 17 00:00:00 2001
From: Thorkil Naur <naur@post11.tele.dk>
Date: Wed, 19 Oct 2011 00:20:53 +0200
Subject: [PATCH] FIX BUILD on OS X 10.5: Check whether ld understands
 -no_compact_unwind

---
 aclocal.m4                      |   25 +++++++++++++++++++++++++
 compiler/ghc.mk                 |    2 ++
 compiler/main/DriverPipeline.hs |    3 ++-
 configure.ac                    |    1 +
 mk/config.mk.in                 |    4 ++++
 5 files changed, 34 insertions(+), 1 deletions(-)

diff --git a/aclocal.m4 b/aclocal.m4
index c8c125a..3841ed7 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -681,6 +681,31 @@ AC_SUBST([LdIsGNULd], [`echo $fp_cv_gnu_ld | sed 'y/yesno/YESNO/'`])
 ])# FP_PROG_LD_IS_GNU
 
 
+# FP_PROG_LD_NO_COMPACT_UNWIND
+# ----------------------------
+
+# Sets the output variable LdHasNoCompactUnwind to YES if ld supports
+# -no_compact_unwind, or NO otherwise.
+AC_DEFUN([FP_PROG_LD_NO_COMPACT_UNWIND],
+[
+AC_CACHE_CHECK([whether ld understands -no_compact_unwind], [fp_cv_ld_no_compact_unwind],
+[echo 'foo() {}' > conftest.c
+${CC-cc} -c conftest.c
+if ${LdCmd} -r -no_compact_unwind -o conftest2.o conftest.o > /dev/null 2>&1; then
+   fp_cv_ld_no_compact_unwind=yes
+else
+   fp_cv_ld_no_compact_unwind=no
+fi
+rm -rf conftest*])
+if test "$fp_cv_ld_no_compact_unwind" = yes; then
+  LdHasNoCompactUnwind=YES
+else
+  LdHasNoCompactUnwind=NO
+fi
+AC_SUBST([LdHasNoCompactUnwind])
+])# FP_PROG_LD_NO_COMPACT_UNWIND
+
+
 # FP_PROG_AR
 # ----------
 # Sets fp_prog_ar_raw to the full path of ar and fp_prog_ar to a non-Cygwin
diff --git a/compiler/ghc.mk b/compiler/ghc.mk
index 54dfa3e..4449a14 100644
--- a/compiler/ghc.mk
+++ b/compiler/ghc.mk
@@ -105,6 +105,8 @@ endif
 	@echo 'cLeadingUnderscore    = "$(LeadingUnderscore)"'              >> $@
 	@echo 'cRAWCPP_FLAGS         :: String'                             >> $@
 	@echo 'cRAWCPP_FLAGS         = "$(RAWCPP_FLAGS)"'                   >> $@
+	@echo 'cLdHasNoCompactUnwind :: String'                             >> $@
+	@echo 'cLdHasNoCompactUnwind = "$(LdHasNoCompactUnwind)"'           >> $@
 	@echo 'cLdIsGNULd            :: String'                             >> $@
 	@echo 'cLdIsGNULd            = "$(LdIsGNULd)"'                      >> $@
 	@echo 'cLdHasBuildId         :: String'                             >> $@
diff --git a/compiler/main/DriverPipeline.hs b/compiler/main/DriverPipeline.hs
index 99d3ce7..fd021cc 100644
--- a/compiler/main/DriverPipeline.hs
+++ b/compiler/main/DriverPipeline.hs
@@ -1683,7 +1683,8 @@ linkBinary dflags o_files dep_packages = do
                       -- like
                       --     ld: warning: could not create compact unwind for .LFB3: non-standard register 5 being saved in prolog
                       -- on x86.
-                      ++ (if platformOS   (targetPlatform dflags) == OSDarwin   &&
+                      ++ (if cLdHasNoCompactUnwind == "YES" &&
+                             platformOS   (targetPlatform dflags) == OSDarwin   &&
                              platformArch (targetPlatform dflags) `elem` [ArchX86, ArchX86_64]
                           then ["-Wl,-no_compact_unwind"]
                           else [])
diff --git a/configure.ac b/configure.ac
index 1207f08..6f36d4f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -697,6 +697,7 @@ dnl ** check for ld, whether it has an -x option, and if it is GNU ld
 FP_PROG_LD_X
 FP_PROG_LD_IS_GNU
 FP_PROG_LD_BUILD_ID
+FP_PROG_LD_NO_COMPACT_UNWIND
 
 dnl ** check for Apple-style dead-stripping support
 dnl    (.subsections-via-symbols assembler directive)
diff --git a/mk/config.mk.in b/mk/config.mk.in
index aef0937..03ea2d1 100644
--- a/mk/config.mk.in
+++ b/mk/config.mk.in
@@ -693,6 +693,10 @@ LdIsGNULd		= @LdIsGNULd@
 # disable it with --build-id=none.
 LdHasBuildId	        = @LdHasBuildId@
 
+# Set to YES if ld has the --no_compact_unwind flag. See #5019
+# and compiler/main/DriverPipeline.hs.
+LdHasNoCompactUnwind	= @LdHasNoCompactUnwind@
+
 # On MSYS, building with SplitObjs=YES fails with 
 #   ar: Bad file number
 # see #3201.  We need to specify a smaller max command-line size
-- 
1.7.6.4