compile-file: need endian mark in .tlo files.

VM machine code is endian-specific: it consists of 32 bit
instruction words which are 32 bit in the local byte order.

Thus code assembled on a little-endian machine won't run
on a big endian-machine, or vice versa: unless we identify
the situation and byte-swap the code when we load it.

* buf.c (buf_swap32): New function.

* buf.h (buf_swap32): Declared.

* parser.c (read_file_common): Decode the third element from
the version: a Boolean indicating big endian, if true.
If the object file's endian is opposite from our endian, then
byte swap the code.

* itypes.c (itypes_init): Oops, calculation of
itypes_little_endian was broken due to classic C =/== typo.
Luckily, nothing has used this flag so far; it's been waiting
for this first use. I caught this due to testing on a PPC64
box.

* share/txr/stdlib/compiler.tl (%big-endian%, %tlo-ver%): New
variables.
(usr:compile-file): The file version comes from %tlo-ver% now,
which includes the big-endian flag.

1 files changed, 8 insertions, 1 deletions

diff --git a/parser.c b/parser.c
index 5d310b5b..93d9703c 100644
--- a/parser.c
+++ b/parser.c
@@ -55,6 +55,8 @@
 #include "cadr.h"
 #include "struct.h"
 #include "parser.h"
+#include "itypes.h"
+#include "buf.h"
 #include "vm.h"
 #include "txr.h"
 #if HAVE_TERMIOS
@@ -611,6 +613,7 @@ static val read_file_common(val stream, val error_stream, val compiled)
   val error_val = gensym(nil);
   val name = stream_get_prop(stream, name_k);
   val first = t;
+  val big_endian = nil;
 
   for (;;) {
     val form = lisp_parse(stream, error_stream, error_val, name, colon_k);
@@ -625,11 +628,12 @@ static val read_file_common(val stream, val error_stream, val compiled)
     }
 
     if (compiled && first) {
-      val major = pop(&form);
+      val major = car(form);
       if (gt(major, zero))
         uw_throwf(error_s,
                   lit("cannot load ~s; it was compiled by a newer implementation"),
                   stream, nao);
+      big_endian = caddr(form);
       first = nil;
     } else if (compiled) {
       for (; form; form = cdr(form)) {
@@ -640,6 +644,9 @@ static val read_file_common(val stream, val error_stream, val compiled)
         val datavec = pop(&item);
         val funvec = car(item);
         val desc = vm_make_desc(nlevels, nregs, bytecode, datavec, funvec);
+        if ((big_endian && itypes_little_endian) ||
+            (!big_endian && !itypes_little_endian))
+          buf_swap32(bytecode);
         (void) vm_execute_toplevel(desc);
         gc_hint(desc);
       }