Implement binary encoder and decoder support

interpreter/binary/decode.ml

@@ -285,6 +285,17 @@ let limits uN s =
   let max = opt uN has_max s in
   at, {min; max}
 
+let memorylimits uN s =
+  let flags = byte s in
+  require (flags land 0xf2 = 0) s (pos s - 1) "malformed limits flags";
+  let has_max = (flags land 1 = 1) in
+  let at = if flags land 4 = 4 then I64AT else I32AT in
+  let has_paget = (flags land 8 = 8) in
+  let min = uN s in
+  let max = opt uN has_max s in
+  let ps = if has_paget then Int32.to_int(u32 s) else 16 in
+  at, {min; max}, (PageT ps)
+
 let tagtype s =
   zero s;
   TagT (typeuse idx s)
@@ -295,8 +306,8 @@ let globaltype s =
   GlobalT (mut, t)
 
 let memorytype s =
-  let at, lim = limits u64 s in
-  MemoryT (at, lim, PageT 16) (* TODO(custom-page-sizes) *)
+  let at, lim, pt = memorylimits u64 s in
+  MemoryT (at, lim, pt)
 
 let tabletype s =
   let t = reftype s in

interpreter/binary/encode.ml

@@ -187,14 +187,19 @@ struct
     let flags = flag (max <> None) 0 + flag (at = I64AT) 2 in
     byte flags; u64 min; opt u64 max
 
+  let memorylimits at {min; max} (PageT ps) =
+    let flags = flag (max <> None) 0 + flag (at = I64AT) 2 + flag (ps <> 16) 3 in
+    let ps_opt = if ps <> 16 then Some (Int32.of_int ps) else None in
+    byte flags; u64 min; opt u64 max; opt u32 ps_opt
+
   let tagtype = function
     | TagT ut -> u32 0x00l; typeuse u32 ut
 
   let globaltype = function
     | GlobalT (mut, t) -> valtype t; mutability mut
 
   let memorytype = function
-    | MemoryT (at, lim, pt) -> limits at lim (* TODO(custom-page-sizes) *)
+    | MemoryT (at, lim, pt) -> memorylimits at lim pt
 
   let tabletype = function
     | TableT (at, lim, t) -> reftype t; limits at lim

test/core/binary.wast

@@ -661,7 +661,7 @@
   (module binary
       "\00asm" "\01\00\00\00"
       "\05\02\01"                           ;; memory section with one entry
-      "\08"                                 ;; malformed memory limits flag
+      "\10"                                 ;; malformed memory limits flag
   )
   "malformed limits flags"
 )

test/core/custom-page-sizes/custom-page-sizes-invalid.wast

@@ -79,7 +79,7 @@
 
 ;; Power of two page size that cannot fit in a u64 to exercise checks against
 ;; shift overflow.
-(assert_malformed
+(assert_invalid
   (module binary
     "\00asm" "\01\00\00\00"
     "\05\04\01"                ;; Memory section
@@ -104,12 +104,12 @@
   (module
     (memory (import "m" "small-pages-memory") 0 (pagesize 65536))
   )
-  "memory types incompatible"
+  "incompatible import type"
 )
 
 (assert_unlinkable
   (module
     (memory (import "m" "large-pages-memory") 0 (pagesize 1))
   )
-  "memory types incompatible"
+  "incompatible import type"
 )