Bug 1472178 - Ref types for wasm globals. r=bbouvier

--HG--
extra : rebase_source : 2f64e3b52649574e350f4b45bad9547fb3e73975

js/src/jit-test/tests/wasm/gc/ref-global.js

@@ -0,0 +1,61 @@
+if (!wasmGcEnabled())
+    quit(0);
+
+// Basic private-to-module functionality.  At the moment all we have is null
+// pointers, not very exciting.
+
+{
+    let bin = wasmTextToBinary(
+        `(module
+
+          (type $point (struct
+                        (field $x f64)
+                        (field $y f64)))
+
+          (global $g1 (mut (ref $point)) (ref.null (ref $point)))
+          (global $g2 (mut (ref $point)) (ref.null (ref $point)))
+          (global $g3 (ref $point) (ref.null (ref $point)))
+
+          (func (export "get") (result (ref $point))
+           (get_global $g1))
+
+          (func (export "copy")
+           (set_global $g2 (get_global $g1)))
+
+          (func (export "clear")
+           (set_global $g1 (get_global $g3))
+           (set_global $g2 (ref.null (ref $point)))))`);
+
+    let mod = new WebAssembly.Module(bin);
+    let ins = new WebAssembly.Instance(mod).exports;
+
+    assertEq(ins.get(), null);
+    ins.copy();                 // Should not crash
+    ins.clear();                // Should not crash
+}
+
+// We can't import a global of a reference type because we don't have a good
+// notion of structural type compatibility yet.
+{
+    let bin = wasmTextToBinary(
+        `(module
+          (type $box (struct (field $val i32)))
+          (import "m" "g" (global (mut (ref $box)))))`);
+
+    assertErrorMessage(() => new WebAssembly.Module(bin), WebAssembly.CompileError,
+                       /unexpected variable type in global import\/export/);
+}
+
+// We can't export a global of a reference type because we can't later import
+// it.  (Once we can export it, the value setter must also perform the necessary
+// subtype check, which implies we have some notion of exporting types, and we
+// don't have that yet.)
+{
+    let bin = wasmTextToBinary(
+        `(module
+          (type $box (struct (field $val i32)))
+          (global $boxg (export "box") (mut (ref $box)) (ref.null (ref $box))))`);
+
+    assertErrorMessage(() => new WebAssembly.Module(bin), WebAssembly.CompileError,
+                       /unexpected variable type in global import\/export/);
+}

js/src/jit-test/tests/wasm/gc/ref.js

@@ -20,12 +20,6 @@ var bin = wasmTextToBinary(
                    (field $x i32)
                    (field $to_odd (ref $odd))))
 
-      ;; No globals of reference type yet.
-      ;;
-      ;;(import "m" "g" (global (ref $cons)))
-      ;;
-      ;;(global $glob (ref $cons) (ref.null $cons))
-
       (import "m" "f" (func $imp (param (ref $cons)) (result (ref $odd))))
 
       ;; The bodies do nothing since we have no operations on structs yet.

js/src/wasm/WasmBaselineCompile.cpp

@@ -8359,6 +8359,7 @@ BaseCompiler::emitGetGlobal()
           case ValType::F64:
             pushF64(value.f64());
             break;
+          case ValType::Ref:
           case ValType::AnyRef:
             pushRef(intptr_t(value.ptr()));
             break;
@@ -8397,6 +8398,7 @@ BaseCompiler::emitGetGlobal()
         pushF64(rv);
         break;
       }
+      case ValType::Ref:
       case ValType::AnyRef: {
         RegPtr rv = needRef();
         ScratchI32 tmp(*this);
@@ -8454,6 +8456,7 @@ BaseCompiler::emitSetGlobal()
         break;
       }
 #ifdef ENABLE_WASM_GC
+      case ValType::Ref:
       case ValType::AnyRef: {
         RegPtr valueAddr(PreBarrierReg);
         needRef(valueAddr);

js/src/wasm/WasmTypes.cpp

@@ -68,8 +68,8 @@ Val::Val(const LitVal& val)
       case ValType::F32: u.f32_ = val.f32(); return;
       case ValType::I64: u.i64_ = val.i64(); return;
       case ValType::F64: u.f64_ = val.f64(); return;
+      case ValType::Ref:
       case ValType::AnyRef: u.ptr_ = val.ptr(); return;
-      case ValType::Ref: break;
     }
     MOZ_CRASH();
 }

js/src/wasm/WasmValidate.cpp

@@ -1644,7 +1644,7 @@ DecodeMemorySection(Decoder& d, ModuleEnvironment* env)
 
 static bool
 DecodeInitializerExpression(Decoder& d, HasGcTypes gcTypesEnabled, const GlobalDescVector& globals,
-                            ValType expected, InitExpr* init)
+                            ValType expected, uint32_t numTypes, InitExpr* init)
 {
     OpBytes op;
     if (!d.readOp(&op))
@@ -1683,12 +1683,18 @@ DecodeInitializerExpression(Decoder& d, HasGcTypes gcTypesEnabled, const GlobalD
         if (gcTypesEnabled == HasGcTypes::False)
             return d.fail("unexpected initializer expression");
         uint8_t valType;
-        uint32_t unusedRefTypeIndex;
+        uint32_t refTypeIndex;
-        if (!d.readValType(&valType, &unusedRefTypeIndex))
+        if (!d.readValType(&valType, &refTypeIndex))
             return false;
-        if (valType != uint8_t(ValType::AnyRef))
+        if (valType == uint8_t(ValType::AnyRef)) {
-            return d.fail("expected anyref as type for ref.null");
+            *init = InitExpr(LitVal(ValType::AnyRef, nullptr));
-        *init = InitExpr(LitVal(ValType::AnyRef, nullptr));
+        } else if (valType == uint8_t(ValType::Ref)) {
+            if (refTypeIndex >= numTypes)
+                return d.fail("invalid reference type for ref.null");
+            *init = InitExpr(LitVal(ValType(ValType::Ref, refTypeIndex), nullptr));
+        } else {
+            return d.fail("expected anyref/ref as type for ref.null");
+        }
         break;
       }
       case uint16_t(Op::GetGlobal): {
@@ -1745,8 +1751,11 @@ DecodeGlobalSection(Decoder& d, ModuleEnvironment* env)
             return false;
 
         InitExpr initializer;
-        if (!DecodeInitializerExpression(d, env->gcTypesEnabled, env->globals, type, &initializer))
+        if (!DecodeInitializerExpression(d, env->gcTypesEnabled, env->globals, type,
+                                         env->types.length(), &initializer))
+        {
             return false;
+        }
 
         env->globals.infallibleAppend(GlobalDesc(initializer, isMutable));
     }
@@ -1927,8 +1936,10 @@ DecodeElemSection(Decoder& d, ModuleEnvironment* env)
 
         InitExpr offset;
         if (!DecodeInitializerExpression(d, env->gcTypesEnabled, env->globals, ValType::I32,
-                                         &offset))
+                                         env->types.length(), &offset))
+        {
             return false;
+        }
 
         uint32_t numElems;
         if (!d.readVarU32(&numElems))
@@ -2098,8 +2109,10 @@ DecodeDataSection(Decoder& d, ModuleEnvironment* env)
 
         DataSegment seg;
         if (!DecodeInitializerExpression(d, env->gcTypesEnabled, env->globals, ValType::I32,
-                                         &seg.offset))
+                                         env->types.length(), &seg.offset))
+        {
             return false;
+        }
 
         if (!d.readVarU32(&seg.length))
             return d.fail("expected segment size");