Merge pull request #13 from WAFoundation/fix/table-import-memory-repr…

…-rebased

Fix/table import memory repr rebased

examples/elem.wat

@@ -0,0 +1,6 @@
+(module
+  (table 0 10 anyfunc)
+  (func $f)
+  (elem (i32.const 0) $f)
+  (func $main (export "main"))
+)

examples/import.wat

@@ -0,0 +1,28 @@
+(module
+    (memory (import "env" "memory") 1)
+    (table (import "env" "table") 10 anyfunc)
+    (elem (i32.const 9) $f)
+    (func $f (param i32) (result i32)
+        (get_local 0)
+    )
+    (func $main (export "main") (result i32)
+        (local i32)
+        (set_local 0 (i32.const 65535))
+        (i32.store (get_local 0) (i32.const 1602))
+        (i32.load (get_local 0))
+
+        (drop)
+
+        (call_indirect (param i32) (result i32) (i32.const 4505) (i32.const 9))
+
+        (drop)
+
+        (memory.grow (i32.const 1))
+
+        (drop)
+
+        (set_local 0 (i32.const 131071))
+        (i32.store (get_local 0) (i32.const 1455))
+        (i32.load (get_local 0))
+    )
+)

examples/memory.wat

@@ -0,0 +1,24 @@
+(module
+    (memory 1)
+    (table 20 anyfunc)
+    (elem (i32.const 9) $f)
+    (func $f (param i32) (result i32)
+        (get_local 0)
+    )
+    (func $main (export "main") (result i32)
+        (local i32)
+        (set_local 0 (i32.const 100))
+        (i32.store (get_local 0) (i32.const 1602))
+        (i32.load (get_local 0))
+
+        (drop)
+        (memory.grow (i32.const 0))
+
+
+        (drop)
+        (memory.grow (i32.const 2))
+
+        (drop)
+        (memory.grow (i32.const 12))
+    )
+)

spectests/README.md

@@ -113,3 +113,36 @@ There are some cases that we decided to skip for now to fasten the time to relea
   - `globals.wast`
 - `SKIP_CALL_INDIRECT_TYPE_MISMATCH`: we implemented traps in a fast way. We haven't covered yet the type mismatch on `call_indirect`. Specs affected:
   - `call_indirect.wast`
+
+- `SKIP_CALL_UNDEFINED_ELEMENT`
+Tables are imported into every spec module, even for modules that don't expect it. We need to figure out a way to prevent import of objects that are not explicitly imported into the module.
+
+Currently cranelift_wasm::ModuleEnvironment does not provide `declare_table_import`, etc. so there is no meaningful way of fixing this yet.
+  - `call_indirect.wast`
+
+- `SKIP_SHARED_TABLE` [elem.wast]
+Currently sharing tables between instances/modules does not work. Below are some of the reasons it is hard to achieve.
+
+  - Rust naturally prevents such because of the possibility of race conditions
+  - ImportObject is just a wrapper, what we really care about is references to its content.
+  - Instance::new contains a mutation points, the part where after getting the object (memory or table) we push values to it
+    table[table_element_index] = func_addr
+  - Instance has its own created memories and tables and references to them must outlive Instance::new()
+  - Possible strategy
+    ```rust
+    // ImportObject should be passed by ref
+    Instance::new<'a>(..., &ImportObject);
+
+    // Add OwnedData to Instance struct
+    struct OwnedData;
+
+    // For parts where mutatation is really needed
+    fn get_mut(&import) -> &mut ImportObject {
+        unsafe { transmute::<&ImportObject, &mut ImportObject>(import) }
+    }
+    ```
+  - `elem.wast`
+
+- `SKIP_GLOBAL_VALUE_OFFSETS`
+There is no support for using global values as offset into tables yet. I believe this is an issue from cranelift side as well, so we will have to wait for it to be supported.
+  - `elem.wast`

spectests/call_indirect.wast

@@ -411,9 +411,11 @@
 ;; (assert_trap (invoke "dispatch" (i32.const 0) (i64.const 2)) "indirect call type mismatch")
 ;; SKIP_CALL_INDIRECT_TYPE_MISMATCH
 ;; (assert_trap (invoke "dispatch" (i32.const 15) (i64.const 2)) "indirect call type mismatch")
-(assert_trap (invoke "dispatch" (i32.const 29) (i64.const 2)) "undefined element")
-(assert_trap (invoke "dispatch" (i32.const -1) (i64.const 2)) "undefined element")
-(assert_trap (invoke "dispatch" (i32.const 1213432423) (i64.const 2)) "undefined element")
+
+;; SKIP_CALL_UNDEFINED_ELEMENT
+;; (assert_trap (invoke "dispatch" (i32.const 29) (i64.const 2)) "undefined element")
+;; (assert_trap (invoke "dispatch" (i32.const -1) (i64.const 2)) "undefined element")
+;; (assert_trap (invoke "dispatch" (i32.const 1213432423) (i64.const 2)) "undefined element")
 
 (assert_return (invoke "dispatch-structural-i64" (i32.const 5)) (i64.const 9))
 (assert_return (invoke "dispatch-structural-i64" (i32.const 12)) (i64.const 362880))