Bug 1308056: wasm: remove default memory/table option and simplify flags; r=luke

MozReview-Commit-ID: IH6rtY4mrkA

--HG--
extra : rebase_source : 0c6e2e31a4556bfcf0a6516ab2ebae253e695f14

js/src/asmjs/WasmBinary.cpp

@@ -148,17 +148,15 @@ wasm::DecodeLimits(Decoder& d, Limits* limits)
     if (!d.readVarU32(&flags))
         return d.fail("expected flags");
 
-    if (flags & ~uint32_t(ResizableFlags::AllowedMask))
-        return d.fail("unexpected bits set in flags: %lu",
-                      (flags & ~uint32_t(ResizableFlags::AllowedMask)));
-
-    if (!(flags & uint32_t(ResizableFlags::Default)))
-        return d.fail("currently, every memory/table must be declared default");
+    // TODO (bug 1310149): tighten this check (s/3/1) when the AngryBots demo
+    // gets updated.
+    if (flags & ~uint32_t(0x3))
+        return d.fail("unexpected bits set in flags: %lu", (flags & ~uint32_t(0x3)));
 
     if (!d.readVarU32(&limits->initial))
         return d.fail("expected initial length");
 
-    if (flags & uint32_t(ResizableFlags::HasMaximum)) {
+    if (flags & 0x1) {
         uint32_t maximum;
         if (!d.readVarU32(&maximum))
             return d.fail("expected maximum length");

js/src/asmjs/WasmBinary.h

@@ -123,13 +123,6 @@ enum class DefinitionKind
     Global                               = 0x03
 };
 
-enum class ResizableFlags
-{
-    Default                              = 0x1,
-    HasMaximum                           = 0x2,
-    AllowedMask                          = 0x3
-};
-
 enum class GlobalFlags
 {
     IsMutable                            = 0x1,

js/src/asmjs/WasmTextToBinary.cpp

@@ -4288,10 +4288,7 @@ EncodeBytes(Encoder& e, AstName wasmName)
 static bool
 EncodeLimits(Encoder& e, const Limits& limits)
 {
-    uint32_t flags = uint32_t(ResizableFlags::Default);
-    if (limits.maximum)
-        flags |= uint32_t(ResizableFlags::HasMaximum);
-
+    uint32_t flags = limits.maximum ? 1 : 0;
     if (!e.writeVarU32(flags))
         return false;
 

js/src/jit-test/lib/wasm-binary.js

@@ -92,6 +92,5 @@ const MemoryCode   = 0x02;
 const GlobalCode   = 0x03;
 
 // ResizableFlags
-const DefaultFlag    = 0x1;
-const HasMaximumFlag = 0x2;
+const HasMaximumFlag = 0x1;
 

js/src/jit-test/tests/wasm/binary.js

@@ -190,18 +190,16 @@ function tableSection(initialSize) {
     var body = [];
     body.push(...varU32(1));           // number of tables
     body.push(...varU32(AnyFuncCode));
-    body.push(...varU32(DefaultFlag)); // for now, no maximum
+    body.push(...varU32(0x0));         // for now, no maximum
     body.push(...varU32(initialSize));
-    // for now, no maximum
     return { name: tableId, body };
 }
 
 function memorySection(initialSize) {
     var body = [];
     body.push(...varU32(1));           // number of memories
-    body.push(...varU32(DefaultFlag)); // for now, no maximum
+    body.push(...varU32(0x0));         // for now, no maximum
     body.push(...varU32(initialSize));
-    // for now, no maximum
     return { name: memoryId, body };
 }