Bug 1467071 - Wasm: import embedding_limits "limits.js" test and fix …

…any resulting failures. r=lth.

The WebAssembly Specification, branch [1] (see also, more generally,
comments in [2]), contains a new test, limits.js, to check whether the
generally agreed embedding limits (numbers of functions, imports, etc) are
observed.  This bug is to import the test and fix any resulting breakage
detected with it.

[1] https://github.com/WebAssembly/spec/tree/embedding_limits
[2] WebAssembly/spec#607

* js/src/wasm/WasmBinaryConstants.h:
  - Added MaxTableMaximumLength as a counterpart to MaxTableInitialLength.
  - Split the constant group into two parts: spec-required, and those
    pertaining only to our own implementation.

* js/src/wasm/WasmJS.cpp  WasmTableObject::construct():
  - Update GetLimits call with correct max size bound

* js/src/wasm/WasmValidate.cpp  DecodeTableLimits():
  - Implement missing check for a Table's maximum size.

* js/src/jit-test/tests/wasm/import-export.js:
  js/src/jit-test/tests/wasm/spec/jsapi.js:
  testing/web-platform/mozilla/tests/wasm/js/jsapi.js:
  - Update Table maximum size tests.  All tests trying to make a Table
    with more than 10,000,000 entries now throw instead of succeeding.

* js/src/jit-test/tests/wasm/spec/harness/wasm-module-builder.js:
  - Import minimal updates and bug fixes from [1], needed to make the
    new tests work.

* js/src/jit-test/tests/wasm/spec/limits.js
  - New file.  Derived from [1], with comments added to each test to show
    SM's compliance situation, and with two tests disabled.

js/src/jit-test/tests/wasm/import-export.js

@@ -37,8 +37,8 @@ assertErrorMessage(() => new Memory({initial: 0, maximum: 65537}), RangeError, /
 assertErrorMessage(() => new Table({initial:2, maximum:1, element:"anyfunc"}), RangeError, /bad Table maximum size/);
 new Table({ initial: 10000000, element:"anyfunc" });
 assertErrorMessage(() => new Table({initial:10000001, element:"anyfunc"}), RangeError, /bad Table initial size/);
-new Table({ initial: 0, maximum: 2**32 - 1, element:"anyfunc" });
-assertErrorMessage(() => new Table({initial:0, maximum: 2**32, element:"anyfunc"}), RangeError, /bad Table maximum size/);
+new Table({ initial: 0, maximum: 10000000, element:"anyfunc" });
+assertErrorMessage(() => new Table({initial:0, maximum: 10000001, element:"anyfunc"}), RangeError, /bad Table maximum size/);
 
 const m1 = new Module(wasmTextToBinary('(module (import "foo" "bar") (import "baz" "quux"))'));
 assertErrorMessage(() => new Instance(m1), TypeError, /second argument must be an object/);

js/src/jit-test/tests/wasm/spec/harness/wasm-module-builder.js

@@ -69,12 +69,14 @@ class Binary extends Array {
     // Emit section name.
     this.emit_u8(section_code);
     // Emit the section to a temporary buffer: its full length isn't know yet.
-    let section = new Binary;
+    const section = new Binary;
     content_generator(section);
     // Emit section length.
     this.emit_u32v(section.length);
     // Copy the temporary buffer.
-    this.push(...section);
+    for (const b of section) {
+      this.push(b);
+    }
   }
 }
 
@@ -238,11 +240,22 @@ class WasmModuleBuilder {
   }
 
   appendToTable(array) {
+    for (let n of array) {
+      if (typeof n != 'number')
+        throw new Error('invalid table (entries have to be numbers): ' + array);
+    }
     return this.addFunctionTableInit(this.function_table.length, false, array);
   }
 
+  setFunctionTableBounds(min, max) {
+    this.function_table_length_min = min;
+    this.function_table_length_max = max;
+    return this;
+  }
+
   setFunctionTableLength(length) {
-    this.function_table_length = length;
+    this.function_table_length_min = length;
+    this.function_table_length_max = length;
     return this;
   }
 
@@ -320,25 +333,29 @@ class WasmModuleBuilder {
     }
 
     // Add function_table.
-    if (wasm.function_table_length > 0) {
+    if (wasm.function_table_length_min > 0) {
       if (debug) print("emitting table @ " + binary.length);
       binary.emit_section(kTableSectionCode, section => {
         section.emit_u8(1);  // one table entry
         section.emit_u8(kWasmAnyFunctionTypeForm);
-        section.emit_u8(1);
-        section.emit_u32v(wasm.function_table_length);
-        section.emit_u32v(wasm.function_table_length);
+        const max = wasm.function_table_length_max;
+        const has_max = max !== undefined;
+        section.emit_u8(has_max ? kResizableMaximumFlag : 0);
+        section.emit_u32v(wasm.function_table_length_min);
+        if (has_max) section.emit_u32v(max);
       });
     }
 
     // Add memory section
-    if (wasm.memory != undefined) {
+    if (wasm.memory !== undefined) {
       if (debug) print("emitting memory @ " + binary.length);
       binary.emit_section(kMemorySectionCode, section => {
         section.emit_u8(1);  // one memory entry
-        section.emit_u32v(kResizableMaximumFlag);
+        const max = wasm.memory.max;
+        const has_max = max !== undefined;
+        section.emit_u32v(has_max ? kResizableMaximumFlag : 0);
         section.emit_u32v(wasm.memory.min);
-        section.emit_u32v(wasm.memory.max);
+        if (has_max) section.emit_u32v(max);
       });
     }
 
@@ -426,9 +443,9 @@ class WasmModuleBuilder {
       binary.emit_section(kElementSectionCode, section => {
         var inits = wasm.function_table_inits;
         section.emit_u32v(inits.length);
-        section.emit_u8(0); // table index
 
         for (let init of inits) {
+          section.emit_u8(0); // table index
           if (init.is_global) {
             section.emit_u8(kExprGetGlobal);
           } else {

js/src/jit-test/tests/wasm/spec/jsapi.js

@@ -557,7 +557,7 @@ test(() => {
     assert_equals(new Table({initial:1, element:"anyfunc"}) instanceof Table, true);
     assert_equals(new Table({initial:1.5, element:"anyfunc"}) instanceof Table, true);
     assert_equals(new Table({initial:1, maximum:1.5, element:"anyfunc"}) instanceof Table, true);
-    assert_equals(new Table({initial:1, maximum:Math.pow(2,32)-1, element:"anyfunc"}) instanceof Table, true);
+    assertThrows(() => new Table({initial:1, maximum:Math.pow(2,32)-1, element:"anyfunc"}), RangeError);
 }, "'WebAssembly.Table' constructor function");
 
 test(() => {