Fixes to get configure ccname=g++ working on OSX Lion.

* Makefile (conftest.syms): Use -n flag in nm so that the output
is not alphabetically sorted, but numerically. We need this
to get the symbols ordered by increasing offset.

* configure (read_syms): New function. Factors out logic used
in two places for reading the output of nm. On OSX Lion, it looks
like we do not get symbol sizes but offsets only, when compiling
with g++. The symbols are in an S section.  When compiling with
gcc, we get a common C section with symbol sizes.
So the hack is to use the deltas between offsets to get the sizes.
The objects had to be re-ordered in decreasing rank so alignment
doesn't create padding that will get counted as the size.
Interleaved dummy objects of type char should also work.

3 files changed, 76 insertions, 37 deletions

diff --git a/ChangeLog b/ChangeLog
index 6ee07d65..abedc1ed 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,23 @@
 2012-04-07  Kaz Kylheku  <kaz@kylheku.com>
 
+	Fixes to get configure ccname=g++ working on OSX Lion.
+
+	* Makefile (conftest.syms): Use -n flag in nm so that the output
+	is not alphabetically sorted, but numerically. We need this
+	to get the symbols ordered by increasing offset.
+
+	* configure (read_syms): New function. Factors out logic used
+	in two places for reading the output of nm. On OSX Lion, it looks
+	like we do not get symbol sizes but offsets only, when compiling
+	with g++. The symbols are in an S section.  When compiling with
+	gcc, we get a common C section with symbol sizes.
+	So the hack is to use the deltas between offsets to get the sizes.
+	The objects had to be re-ordered in decreasing rank so alignment
+	doesn't create padding that will get counted as the size.
+	Interleaved dummy objects of type char should also work.
+
+2012-04-07  Kaz Kylheku  <kaz@kylheku.com>
+
 	* configure: Print done and terminate line after checking for
 	clashing symbols.
 
diff --git a/Makefile b/Makefile
index 19fabd4b..f784b7e0 100644
--- a/Makefile
+++ b/Makefile
@@ -181,7 +181,7 @@ conftest2: conftest1.c conftest2.c
 	$(CC) $(CFLAGS) -o $@ $^
 
 conftest.syms: conftest.o
-	$(NM) -t o -P $^ > $@
+	$(NM) -n -t o -P $^ > $@
 
 .PHONY: conftest.yacc
 conftest.yacc:
diff --git a/configure b/configure
index ebd02aec..46667045 100755
--- a/configure
+++ b/configure
@@ -711,19 +711,61 @@ fi
 
 printf "Checking what C integer type can hold a pointer ... "
 
+read_syms()
+{
+  print_into_config=${1-} 
+  deferred_offset=
+
+  while read symbol type offset size ; do
+    size=$(( 0$size + 0 ))
+    offset=$(( 0$offset + 0 ))
+    symbol=${symbol#_}
+    case "$type" in
+    C )
+      size=$(( offset + 0 ))
+      ;;
+    S )
+      if [ -n "$deferred_offset" ] ; then
+	size=$(( offset - deferred_offset ))
+	case "$deferred_sym" in
+	SIZEOF* )
+	  eval $(printf "%s=%d\n" "$deferred_sym" "$size")
+          if [ -n "$print_into_config" ] ; then
+	    printf "#define %s %s\n" "$deferred_sym" "$size" >> config.h
+          fi
+	  ;;
+	esac
+      fi
+      deferred_sym=$symbol
+      deferred_offset=$offset
+      continue
+      ;;
+    esac
+    case "$symbol" in
+    SIZEOF* )
+      eval $(printf "%s=%d\n" "$symbol" "$size")
+      if [ -n "$print_into_config" ] ; then
+        printf "#define %s %s\n" "$symbol" "$size" >> config.h
+      fi
+      ;;
+    esac
+  done < conftest.syms
+}
+
 if [ -z "$intptr" ] ; then
   cat > conftest.c <<!
 #include "config.h"
-char SIZEOF_PTR[sizeof (char *)];
-char SIZEOF_SHORT[sizeof (short)];
-char SIZEOF_INT[sizeof (int)];
-char SIZEOF_LONG[sizeof (long)];
-#ifdef HAVE_LONGLONG_T
-char SIZEOF_LONGLONG_T[sizeof (longlong_t)];
-#endif
 #ifdef HAVE_SUPERLONG_T
 char SIZEOF_SUPERLONG_T[sizeof (superlong_t)];
 #endif
+#ifdef HAVE_LONGLONG_T
+char SIZEOF_LONGLONG_T[sizeof (longlong_t)];
+#endif
+char SIZEOF_PTR[sizeof (char *)];
+char SIZEOF_LONG[sizeof (long)];
+char SIZEOF_INT[sizeof (int)];
+char SIZEOF_SHORT[sizeof (short)];
+char DUMMY;
 !
   rm -f conftest.o conftest.syms
 
@@ -742,19 +784,7 @@ char SIZEOF_SUPERLONG_T[sizeof (superlong_t)];
   SIZEOF_LONGLONG_T=0
   SIZEOF_SUPERLONG_T=0
 
-  while read symbol type offset size ; do
-    size=$(( 0$size + 0 ))
-    symbol=${symbol#_}
-    if [ "$type" = "C" ] ; then
-      size=$(( 0$offset + 0 ))
-    fi
-    case "$symbol" in
-    SIZEOF* )
-      eval $(printf "%s=%d\n" "$symbol" "$size")
-      printf "#define %s %s\n" "$symbol" "$size" >> config.h
-      ;;
-    esac
-  done < conftest.syms
+  read_syms y
 
   rm -f conftest.syms conftest.o
 
@@ -823,7 +853,8 @@ printf "Conservatively guessing the alignment of wide literals ... "
 if [ -z "$lit_align" ] ; then
   cat > conftest.c <<!
 #include <wchar.h>
-char sizeof_wchar_t[sizeof (wchar_t)];
+char SIZEOF_WCHAR_T[sizeof (wchar_t)];
+char DUMMY;
 !
   rm -f conftest.o conftest.syms
 
@@ -835,29 +866,19 @@ char sizeof_wchar_t[sizeof (wchar_t)];
     exit 1
   fi
 
-  sizeof_wchar_t=0
+  SIZEOF_WCHAR_T=0
+  deferred_offset=
 
-  while read symbol type offset size ; do
-    size=$(( 0$size + 0 ))
-    symbol=${symbol#_}
-    if [ "$type" = "C" ] ; then
-      size=$(( 0$offset + 0 ))
-    fi
-    case "$symbol" in
-    sizeof* )
-      eval $(printf "%s=%d\n" "$symbol" "$size")
-      ;;
-    esac
-  done < conftest.syms
+  read_syms
 
   rm -f conftest.syms conftest.o
 
-  if [ $sizeof_wchar_t -eq 0 ] ; then
+  if [ $SIZEOF_WCHAR_T -eq 0 ] ; then
     printf "failed\n"
     exit 1
   fi
 
-  lit_align=$sizeof_wchar_t
+  lit_align=$SIZEOF_WCHAR_T
 fi
 
 printf "%d\n" "$lit_align"