Builds (but doesn't run) on Mac OS X

README

@@ -36,9 +36,15 @@ glibc-devel.i386 and libgcc.i386) then try this hack
   make
   make install
 
-Syn68k currently doesn't build under Mac OS X (tested under 10.5.7)
-do to our unconditional use of "-z execstack" when linking as well as
-the fact that i486-cleanup.pl essentially consumes all of syn68k.s.
+To compile syn68k on Mac OS X (tested under 10.5.7), you currently have to
+override the cleanup script, since the stock script (i486-cleanup.pl) will
+consume all of syn68k.s.  However, even if you do this, the resultant binary
+will not work.
+
+  ./autogen.sh
+  CLEANUP='' ./configure
+  make
+  make install
 
 To test syn68k, run test/syngentest and compare the output to
 test/output/10000.  It should be the same.  If you want to be
@@ -48,7 +54,8 @@ results to other files, as described in test/output/README.
 Performance nit:
 
 The code in runtime/i486-cleanup.pl no longer gets rid of all the
-cruft in the trailer.  It's quite possible that the code in
+cruft in the trailer (except under Mac OS X, where it gets rid of way
+too much code).  It's quite possible that the code in
 runtime/i486-optimize.pl doesn't do the right thing either.
 
 My email address is still <ctm@ardi.com>, although ARDI itself is

TODO

@@ -1,7 +1,5 @@
         Mac OS X fixes:
 
-                Don't link with -z execstack if that's going to fail
-
                 figure out why i486-cleanup.pl basically eats all
                 of syn68k.s
 

runtime/Makefile.am

@@ -25,7 +25,7 @@ OBJS =	block.o diagnostics.o hash.o rangetree.o translate.o alloc.o	\
 	blockinfo.o trap.o destroyblock.o callback.o init.o interrupt.o	\
 	profile.o dosinterrupts.o deathqueue.o checksum.o native.o	\
 	backpatch.o recompile.o						\
-	mapindex.o mapinfo.o syn68k.o
+	mapindex.o mapinfo.o syn68k.o opcode_dummy.o
 
 mapinfo.o:	$(host_native)/host-xlate.h
 

runtime/opcode_dummy.c

@@ -0,0 +1,16 @@
+#include <stdio.h>
+
+/*
+ * s68k_handle_opcode_dummy is used to detect portions of assembly in
+ * syn68k.s that are unreachable and should be removed via
+ * i486-cleanup.pl.  The call to s68k_handle_opcode_dummy should never
+ * be made.  It won't be reachable even if i486-cleanup.pl isn't run,
+ * but it will be assembled and linked in, so that's why we actually
+ * supply s68k_handle_opcode_dummy but expect it to never be called.
+ */
+
+void s68k_handle_opcode_dummy (void)
+{
+  fprintf (stderr, "This function should never be called\n");
+  abort ();
+}

runtime/syn68k_header.c

@@ -217,7 +217,7 @@ extern void s68k_handle_opcode_dummy (void);
   asm volatile ("movl %3,%0\n\t" \
 		"addl %4,%1\n\t" \
 		"jmp *%0\n" \
-		"_S68K_DONE_WITH_THIS:" \
+		"/* _S68K_DONE_WITH_THIS: */"                 \
 		: "=r" (next_code), "=r" (code) : "1" (code), \
 		"g" (*(void **)(code + (words_to_inc) - PTR_WORDS)), \
 		"g" (words_to_inc * sizeof (uint16))); \