flambda-backend: Fix mixed block macros so users don't get wrong plat…

…form's macros (#2494)

runtime/alloc.c

@@ -100,7 +100,7 @@ CAMLexport value caml_alloc_mixed_shr_check_gc (mlsize_t wosize, tag_t tag,
                                                 mlsize_t scannable_prefix_len)
 {
   reserved_t reserved =
-    Reserved_mixed_block_scannable_wosize(scannable_prefix_len);
+    Reserved_mixed_block_scannable_wosize_native(scannable_prefix_len);
   return caml_alloc_shr_reserved_check_gc(wosize, tag, reserved);
 }
 #endif
@@ -371,7 +371,7 @@ CAMLprim value caml_alloc_dummy_mixed (value size, value scannable_size)
   */
   CAML_STATIC_ASSERT(Double_wosize == 1);
   reserved_t reserved =
-    Reserved_mixed_block_scannable_wosize(scannable_wosize);
+    Reserved_mixed_block_scannable_wosize_native(scannable_wosize);
 #else
   /* [scannable_size] can't be used meaningfully in bytecode */
   (void)scannable_size;

runtime/caml/mlvalues.h

@@ -150,23 +150,14 @@ mixed blocks. In the upstream compiler, R is set with the
 
 #endif
 
-/* Header bits reserved for mixed blocks */
 
-#define Is_mixed_block_reserved(res)               (((reserved_t)(res)) > 0)
+/* Header bits reserved for mixed blocks */
 
-#ifdef NATIVE_CODE
-#define Scannable_wosize_val(val) (Scannable_wosize_hd (Hd_val (val)))
-#define Reserved_mixed_block_scannable_wosize(sz)  (((mlsize_t)(sz)) + 1)
-#define Mixed_block_scannable_wosize_reserved_native(res) (((reserved_t)(res)) - 1)
+#define Is_mixed_block_reserved(res) (((reserved_t)(res)) > 0)
 
-Caml_inline mlsize_t Scannable_wosize_reserved(reserved_t res, mlsize_t sz) {
-  return
-    Is_mixed_block_reserved(res)
-    ? Mixed_block_scannable_wosize_reserved_native(res)
-    : sz;
-}
+/* Native code versions of mixed block macros.
 
-/* The scannable size of a block is how many fields are values as opposed
+   The scannable size of a block is how many fields are values as opposed
    to flat floats/ints/etc. This is different than the (normal) size of a
    block for mixed blocks.
 
@@ -182,25 +173,61 @@ Caml_inline mlsize_t Scannable_wosize_reserved(reserved_t res, mlsize_t sz) {
    Otherwise, the traversal could attempt to recursively descend into
    a flat field, which could segfault (or worse).
 */
-Caml_inline mlsize_t Scannable_wosize_hd(header_t hd) {
+
+#define Scannable_wosize_val_native(val) (Scannable_wosize_hd (Hd_val (val)))
+#define Reserved_mixed_block_scannable_wosize_native(sz)  (((mlsize_t)(sz)) + 1)
+#define Mixed_block_scannable_wosize_reserved_native(res) \
+  (((reserved_t)(res)) - 1)
+
+Caml_inline mlsize_t Scannable_wosize_reserved_native(reserved_t res,
+                                                      mlsize_t sz) {
+  return
+    Is_mixed_block_reserved(res)
+    ? Mixed_block_scannable_wosize_reserved_native(res)
+    : sz;
+}
+
+Caml_inline mlsize_t Scannable_wosize_hd_native(header_t hd) {
   reserved_t res = Reserved_hd(hd);
   return
     Is_mixed_block_reserved(res)
     ? Mixed_block_scannable_wosize_reserved_native(res)
     : Wosize_hd(hd);
 }
 
-#else
-#define Scannable_wosize_hd(val)  (Wosize_hd (val))
-#define Scannable_wosize_val(val) (Wosize_hd (Hd_val (val)))
-#define Faux_mixed_block_sentinel ((reserved_t) 0xff)
+/* Bytecode versions of mixed block macros.
 
-// In bytecode always use the size of the block as the scannable size
-Caml_inline mlsize_t Scannable_wosize_reserved(reserved_t res, mlsize_t size) {
+   Bytecode always uses the size of the block as the scannable size. That's
+   because bytecode doesn't represent mixed records as mixed blocks. They're
+   "faux mixed blocks", which are regular blocks with a sentinel value set
+   in the header bits.
+*/
+
+#define Scannable_wosize_hd_byte(hd)  (Wosize_hd (hd))
+#define Scannable_wosize_val_byte(val) (Wosize_hd (Hd_val (val)))
+Caml_inline mlsize_t Scannable_wosize_reserved_byte(reserved_t res,
+                                                    mlsize_t size) {
+  (void)res;
   return size;
 }
 
+/* Users should specify whether they want to use the bytecode or native
+   versions of these macros. Internally to the runtime, the NATIVE_CODE
+   macro lets us make that determination, so we can define suffixless
+   versions of the mixed block macros.
+*/
+#ifdef CAML_INTERNALS
+#ifdef NATIVE_CODE
+#define Scannable_wosize_reserved(r, s) Scannable_wosize_reserved_native(r, s)
+#define Scannable_wosize_hd(hd)         Scannable_wosize_hd_native(hd)
+#define Scannable_wosize_val(val)       Scannable_wosize_val_native(val)
+#else
+#define Faux_mixed_block_sentinel ((reserved_t) 0xff)
+#define Scannable_wosize_reserved(r, s) Scannable_wosize_reserved_byte(r, s)
+#define Scannable_wosize_hd(hd)         Scannable_wosize_hd_byte(hd)
+#define Scannable_wosize_val(val)       Scannable_wosize_val_byte(val)
 #endif // NATIVE_CODE
+#endif // CAML_INTERNALS
 
 /* Color values are pre-shifted */
 

runtime4/alloc.c

@@ -71,7 +71,7 @@ CAMLexport value caml_alloc (mlsize_t wosize, tag_t tag) {
 CAMLexport value caml_alloc_mixed (mlsize_t wosize, tag_t tag,
                                    mlsize_t scannable_prefix) {
   reserved_t reserved =
-    Reserved_mixed_block_scannable_wosize(scannable_prefix);
+    Reserved_mixed_block_scannable_wosize_native(scannable_prefix);
   return caml_alloc_with_reserved (wosize, tag, reserved);
 }
 #endif // NATIVE_CODE
@@ -263,7 +263,7 @@ CAMLprim value caml_alloc_dummy_mixed (value size, value scannable_size)
   */
   CAML_STATIC_ASSERT(Double_wosize == 1);
   reserved_t reserved =
-    Reserved_mixed_block_scannable_wosize(scannable_wosize);
+    Reserved_mixed_block_scannable_wosize_native(scannable_wosize);
 #else
   /* [scannable_size] can't be used meaningfully in bytecode */
   (void)scannable_size;

runtime4/caml/mlvalues.h

@@ -145,21 +145,11 @@ originally built for Spacetime profiling, hence the odd name.
 #define Reserved_hd(hd) ((reserved_t)(Profinfo_hd(hd)))
 #define Reserved_val(val) ((reserved_t)(Profinfo_val(val)))
 
-#define Is_mixed_block_reserved(res)               (((reserved_t)(res)) > 0)
+#define Is_mixed_block_reserved(res) (((reserved_t)(res)) > 0)
 
-#ifdef NATIVE_CODE
-#define Scannable_wosize_val(val) (Scannable_wosize_hd (Hd_val (val)))
-#define Reserved_mixed_block_scannable_wosize(sz)  (((mlsize_t)(sz)) + 1)
-#define Mixed_block_scannable_wosize_reserved_native(res) (((reserved_t)(res)) - 1)
-
-Caml_inline mlsize_t Scannable_wosize_reserved(reserved_t res, mlsize_t sz) {
-  return
-    Is_mixed_block_reserved(res)
-    ? Mixed_block_scannable_wosize_reserved_native(res)
-    : sz;
-}
+/* Native code versions of mixed block macros.
 
-/* The scannable size of a block is how many fields are values as opposed
+   The scannable size of a block is how many fields are values as opposed
    to flat floats/ints/etc. This is different than the (normal) size of a
    block for mixed blocks.
 
@@ -175,25 +165,61 @@ Caml_inline mlsize_t Scannable_wosize_reserved(reserved_t res, mlsize_t sz) {
    Otherwise, the traversal could attempt to recursively descend into
    a flat field, which could segfault (or worse).
 */
-Caml_inline mlsize_t Scannable_wosize_hd(header_t hd) {
+
+#define Scannable_wosize_val_native(val) (Scannable_wosize_hd (Hd_val (val)))
+#define Reserved_mixed_block_scannable_wosize_native(sz)  (((mlsize_t)(sz)) + 1)
+#define Mixed_block_scannable_wosize_reserved_native(res) \
+  (((reserved_t)(res)) - 1)
+
+Caml_inline mlsize_t Scannable_wosize_reserved_native(reserved_t res,
+                                                      mlsize_t sz) {
+  return
+    Is_mixed_block_reserved(res)
+    ? Mixed_block_scannable_wosize_reserved_native(res)
+    : sz;
+}
+
+Caml_inline mlsize_t Scannable_wosize_hd_native(header_t hd) {
   reserved_t res = Reserved_hd(hd);
   return
     Is_mixed_block_reserved(res)
     ? Mixed_block_scannable_wosize_reserved_native(res)
     : Wosize_hd(hd);
 }
 
-#else
-#define Scannable_wosize_hd(val)  (Wosize_hd (val))
-#define Scannable_wosize_val(val) (Wosize_hd (Hd_val (val)))
-#define Faux_mixed_block_sentinel ((reserved_t) 0xff)
+/* Bytecode versions of mixed block macros.
 
-// In bytecode always use the size of the block as the scannable size
-Caml_inline mlsize_t Scannable_wosize_reserved(reserved_t res, mlsize_t size) {
+   Bytecode always uses the size of the block as the scannable size. That's
+   because bytecode doesn't represent mixed records as mixed blocks. They're
+   "faux mixed blocks", which are regular blocks with a sentinel value set
+   in the header bits.
+*/
+
+#define Scannable_wosize_hd_byte(hd)  (Wosize_hd (hd))
+#define Scannable_wosize_val_byte(val) (Wosize_hd (Hd_val (val)))
+Caml_inline mlsize_t Scannable_wosize_reserved_byte(reserved_t res,
+                                                    mlsize_t size) {
+  (void)res;
   return size;
 }
 
+/* Users should specify whether they want to use the bytecode or native
+   versions of these macros. Internally to the runtime, the NATIVE_CODE
+   macro lets us make that determination, so we can define suffixless
+   versions of the mixed block macros.
+*/
+#ifdef CAML_INTERNALS
+#ifdef NATIVE_CODE
+#define Scannable_wosize_reserved(r, s) Scannable_wosize_reserved_native(r, s)
+#define Scannable_wosize_hd(hd)         Scannable_wosize_hd_native(hd)
+#define Scannable_wosize_val(val)       Scannable_wosize_val_native(val)
+#else
+#define Faux_mixed_block_sentinel ((reserved_t) 0xff)
+#define Scannable_wosize_reserved(r, s) Scannable_wosize_reserved_byte(r, s)
+#define Scannable_wosize_hd(hd)         Scannable_wosize_hd_byte(hd)
+#define Scannable_wosize_val(val)       Scannable_wosize_val_byte(val)
 #endif // NATIVE_CODE
+#endif // CAML_INTERNALS
 
 #define Hd_val(val) (((header_t *) (val)) [-1])        /* Also an l-value. */
 #define Hd_op(op) (Hd_val (op))                        /* Also an l-value. */