Bug 1546138 - Wasm: Implement 'ref.func'. r=bbouvier

This commit implements the 'ref.func' instruction by emitting an instance call
to WasmInstanceObject::getExportedFunction.

The referenced function must be used in an element segment to validate.
See [1] for more details.

[1] WebAssembly/reference-types#31

Differential Revision: https://phabricator.services.mozilla.com/D40586

UltraBlame original commit: 00e5548e9c435314beb0c572e1476330b06e1d6d

Author: marco-c

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

@@ -2251,6 +2251,7 @@ MemoryGrow
 MemorySize
 Nop
 Pop
+RefFunc
 RefNull
 Return
 SetGlobal
@@ -8801,6 +8802,61 @@ operand_
 }
 ;
 class
+AstRefFunc
+final
+:
+public
+AstExpr
+{
+AstRef
+func_
+;
+public
+:
+static
+const
+AstExprKind
+Kind
+=
+AstExprKind
+:
+:
+RefFunc
+;
+explicit
+AstRefFunc
+(
+AstRef
+func
+)
+:
+AstExpr
+(
+Kind
+ExprType
+:
+:
+FuncRef
+)
+func_
+(
+func
+)
+{
+}
+AstRef
+&
+func
+(
+)
+{
+return
+func_
+;
+}
+}
+;
+class
 AstRefNull
 final
 :

js/src/wasm/WasmAST.h

@@ -32909,6 +32909,12 @@ emitMemorySize
 ;
 MOZ_MUST_USE
 bool
+emitRefFunc
+(
+)
+;
+MOZ_MUST_USE
+bool
 emitRefNull
 (
 )
@@ -47205,6 +47211,62 @@ bool
 BaseCompiler
 :
 :
+emitRefFunc
+(
+)
+{
+uint32_t
+lineOrBytecode
+=
+readCallSiteLineOrBytecode
+(
+)
+;
+uint32_t
+funcIndex
+;
+if
+(
+!
+iter_
+.
+readRefFunc
+(
+&
+funcIndex
+)
+)
+{
+return
+false
+;
+}
+if
+(
+deadCode_
+)
+{
+return
+true
+;
+}
+pushI32
+(
+funcIndex
+)
+;
+return
+emitInstanceCall
+(
+lineOrBytecode
+SASigFuncRef
+)
+;
+}
+bool
+BaseCompiler
+:
+:
 emitRefNull
 (
 )
@@ -56563,6 +56625,24 @@ uint16_t
 Op
 :
 :
+RefFunc
+)
+:
+CHECK_NEXT
+(
+emitRefFunc
+(
+)
+)
+;
+break
+;
+case
+uint16_t
+(
+Op
+:
+:
 RefNull
 )
 :

js/src/wasm/WasmBaselineCompile.cpp

@@ -913,6 +913,25 @@ _END
 ;
 const
 SymbolicAddressSignature
+SASigFuncRef
+=
+{
+SymbolicAddress
+:
+:
+FuncRef
+_RoN
+_FailOnInvalidRef
+2
+{
+_PTR
+_I32
+_END
+}
+}
+;
+const
+SymbolicAddressSignature
 SASigPostBarrier
 =
 {
@@ -4795,6 +4814,28 @@ case
 SymbolicAddress
 :
 :
+FuncRef
+:
+*
+abiType
+=
+Args_General2
+;
+return
+FuncCast
+(
+Instance
+:
+:
+funcRef
+*
+abiType
+)
+;
+case
+SymbolicAddress
+:
+:
 PostBarrier
 :
 *
@@ -5484,6 +5525,12 @@ case
 SymbolicAddress
 :
 :
+FuncRef
+:
+case
+SymbolicAddress
+:
+:
 PostBarrier
 :
 case

js/src/wasm/WasmBuiltins.cpp

@@ -200,6 +200,11 @@ SASigTableSize
 extern
 const
 SymbolicAddressSignature
+SASigFuncRef
+;
+extern
+const
+SymbolicAddressSignature
 SASigPostBarrier
 ;
 extern

js/src/wasm/WasmBuiltins.h

@@ -7353,6 +7353,23 @@ case
 SymbolicAddress
 :
 :
+FuncRef
+:
+return
+"
+call
+to
+native
+func
+.
+ref
+function
+"
+;
+case
+SymbolicAddress
+:
+:
 PostBarrier
 :
 return