From e6a7729d2ff6fb7577e4bf153462976ba5eae777 Mon Sep 17 00:00:00 2001
From: Taylor R Campbell <campbell@mumble.net>
Date: Wed, 12 Dec 2018 19:33:05 +0000
Subject: [PATCH] Distinguish bytes-per-object from target-bytes-per-object.

This is a kludge for now until we have a syntactic tower where we can
use distinct environments at each level of syntax expansion.
---
 src/Makefile.in              |  6 ++++--
 src/configure.ac             |  4 ++++
 src/runtime/boot.scm         | 10 +++++++++-
 src/runtime/bytevector.scm   |  9 ++++++++-
 src/runtime/host-adapter.scm |  5 +++++
 src/runtime/runtime.pkg      |  1 +
 src/runtime/sysmac.scm       |  2 +-
 7 files changed, 32 insertions(+), 5 deletions(-)

diff --git a/src/Makefile.in b/src/Makefile.in
index cb5a0c278..f7470c382 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -75,7 +75,9 @@ AUXDIR = @AUXDIR@
 @IF_CROSS@COMPILER_SETTINGS_CROSS = (set! compiler:cross-compiling? true)
 @IF_CROSS@SF_SETTINGS_CROSS = \
 @IF_CROSS@	(set! sf/cross-compiling? true) \
-@IF_CROSS@	(set! package/cross-compiling? true)
+@IF_CROSS@	(set! package/cross-compiling? true) \
+@IF_CROSS@	(set! target-bytes-per-object \
+@IF_CROSS@	      (lambda () @mit_scheme_target_bytes_per_object@))
 @IF_LIARC@COMPILER_SETTINGS_LIARC = (set! compiler:invoke-c-compiler? false)
 HOST_COMPILER_HEAP = @HOST_COMPILER_HEAP@
 
@@ -85,7 +87,7 @@ HOST_COMPILER_SETTINGS = \
 	$(COMPILER_SETTINGS_LIARC)
 
 HOST_COMPILER = '$(MIT_SCHEME_EXE)' --batch-mode $(HOST_COMPILER_HEAP) --no-init-file \
-  --eval '(begin $(HOST_COMPILER_SETTINGS))' --load runtime/host-adapter.scm
+  --load runtime/host-adapter.scm --eval '(begin $(HOST_COMPILER_SETTINGS))'
 
 HOST_RUNTIME_ONLY = '$(MIT_SCHEME_EXE)' --batch-mode $(HOST_COMPILER_HEAP) \
   --band runtime.com --no-init-file --load runtime/host-adapter.scm
diff --git a/src/configure.ac b/src/configure.ac
index 5456b89bd..e625cde9f 100644
--- a/src/configure.ac
+++ b/src/configure.ac
@@ -139,6 +139,9 @@ AC_ARG_ENABLE([mcrypt],
 
 AC_CANONICAL_HOST
 
+AC_CHECK_SIZEOF([unsigned long])
+mit_scheme_target_bytes_per_object=$ac_cv_sizeof_unsigned_long
+
 ALL_TARGET=all-native
 INSTALL_COM='$(INSTALL_DATA)'
 INSTALL_LIARC_BUNDLES=
@@ -386,6 +389,7 @@ AC_SUBST([INSTALL_COM])
 AC_SUBST([INSTALL_LIARC_BUNDLES])
 AC_SUBST([MIT_SCHEME_EXE])
 AC_SUBST([mit_scheme_native_code])
+AC_SUBST([mit_scheme_target_bytes_per_object])
 AC_SUBST([OPTION_SUBDIRS])
 
 AC_PROG_INSTALL
diff --git a/src/runtime/boot.scm b/src/runtime/boot.scm
index c73ab8d73..ff5a7a5ef 100644
--- a/src/runtime/boot.scm
+++ b/src/runtime/boot.scm
@@ -508,4 +508,12 @@ USA.
   ((ucode-primitive gc-space-status)))
 
 (define (bytes-per-object)
-  (vector-ref (gc-space-status) 0))
\ No newline at end of file
+  (vector-ref (gc-space-status) 0))
+
+;;; XXX Cross-compilation kludge: We redefine this to return the
+;;; characteristic of the target system.  In the future, macro
+;;; expanders should just see a binding of bytes-per-object that
+;;; reflects the target system.
+
+(define (target-bytes-per-object)
+  (bytes-per-object))
\ No newline at end of file
diff --git a/src/runtime/bytevector.scm b/src/runtime/bytevector.scm
index a77216998..8743437c4 100644
--- a/src/runtime/bytevector.scm
+++ b/src/runtime/bytevector.scm
@@ -205,9 +205,16 @@ USA.
    (lambda (form rename compare)
      rename compare
      (syntax-check '(_ expression expression) form)
+     ;; XXX This queries the host system rather than the target system.
+     ;; We should expose definitions of fix:fixnum? to macro expanders
+     ;; that reflect the target system instead.
+     #;
      (if (fix:fixnum? #xFFFFFFFF)
 	 (cadr form)
-	 (caddr form)))))
+	 (caddr form))
+     ;; XXX For now, we can use the number of bytes per word as a proxy
+     ;; for whether fixnums have 32 bits.
+     `(select-on-bytes-per-word ,(caddr form) ,(cadr form)))))
 
 (select-u32-code
  ;; Can use fixnums:
diff --git a/src/runtime/host-adapter.scm b/src/runtime/host-adapter.scm
index e7af3e285..4a9461158 100644
--- a/src/runtime/host-adapter.scm
+++ b/src/runtime/host-adapter.scm
@@ -35,4 +35,9 @@ USA.
 ;;; the new runtime.  It contains temporary hacks that will be kept
 ;;; only until the new runtime is released.
 
+(if (lexical-unreferenceable? (->environment '()) 'target-bytes-per-object)
+    (environment-define (->environment '())
+			'target-bytes-per-object
+			bytes-per-object))
+
 unspecific
\ No newline at end of file
diff --git a/src/runtime/runtime.pkg b/src/runtime/runtime.pkg
index efd7d106c..f1e87b223 100644
--- a/src/runtime/runtime.pkg
+++ b/src/runtime/runtime.pkg
@@ -203,6 +203,7 @@ USA.
 	  set-predicate<=!
 	  simple-parser-method
 	  standard-print-method
+	  target-bytes-per-object
 	  weak-car
 	  weak-cdr
 	  weak-cons
diff --git a/src/runtime/sysmac.scm b/src/runtime/sysmac.scm
index 47900b49e..1f9f216d5 100644
--- a/src/runtime/sysmac.scm
+++ b/src/runtime/sysmac.scm
@@ -112,7 +112,7 @@ USA.
    (lambda (form rename compare)
      (declare (ignore rename compare))
      (syntax-check '(_ expression expression) form)
-     (let ((bpo (bytes-per-object)))
+     (let ((bpo (target-bytes-per-object)))
        (case bpo
 	 ((4) (cadr form))
 	 ((8) (caddr form))
-- 
2.25.1