[wasm-gc] Implement i31ref

This patch does not include support for RTTs for i31ref yet.

Bug: v8:7748
Change-Id: Ifbeb8e305c2d0a57e4d5d6be761d046e330e0da1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2273135
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#68613}

src/compiler/graph-assembler.h

@@ -94,6 +94,7 @@ class BasicBlock;
   V(WordSar)                              \
   V(WordSarShiftOutZeros)                 \
   V(WordShl)                              \
+  V(WordShr)                              \
   V(WordXor)
 
 #define CHECKED_ASSEMBLER_MACH_BINOP_LIST(V) \

src/compiler/wasm-compiler.cc

@@ -5432,6 +5432,38 @@ Node* WasmGraphBuilder::ArrayLen(Node* array_object,
   return ArrayLength(gasm_.get(), array_object);
 }
 
+// 1 bit V8 Smi tag, 31 bits V8 Smi shift, 1 bit i31ref high-bit truncation.
+constexpr int kI31To32BitSmiShift = 33;
+
+Node* WasmGraphBuilder::I31New(Node* input) {
+  if (SmiValuesAre31Bits()) {
+    return gasm_->Word32Shl(input, BuildSmiShiftBitsConstant32());
+  }
+  DCHECK(SmiValuesAre32Bits());
+  input = BuildChangeInt32ToIntPtr(input);
+  return gasm_->WordShl(input, gasm_->IntPtrConstant(kI31To32BitSmiShift));
+}
+
+Node* WasmGraphBuilder::I31GetS(Node* input) {
+  if (SmiValuesAre31Bits()) {
+    input = BuildTruncateIntPtrToInt32(input);
+    return gasm_->Word32SarShiftOutZeros(input, BuildSmiShiftBitsConstant32());
+  }
+  DCHECK(SmiValuesAre32Bits());
+  return BuildTruncateIntPtrToInt32(
+      gasm_->WordSar(input, gasm_->IntPtrConstant(kI31To32BitSmiShift)));
+}
+
+Node* WasmGraphBuilder::I31GetU(Node* input) {
+  if (SmiValuesAre31Bits()) {
+    input = BuildTruncateIntPtrToInt32(input);
+    return gasm_->Word32Shr(input, BuildSmiShiftBitsConstant32());
+  }
+  DCHECK(SmiValuesAre32Bits());
+  return BuildTruncateIntPtrToInt32(
+      gasm_->WordShr(input, gasm_->IntPtrConstant(kI31To32BitSmiShift)));
+}
+
 class WasmDecorator final : public GraphDecorator {
  public:
   explicit WasmDecorator(NodeOriginTable* origins, wasm::Decoder* decoder)

src/compiler/wasm-compiler.h

@@ -399,6 +399,9 @@ class WasmGraphBuilder {
                  Node* value, CheckForNull null_check,
                  wasm::WasmCodePosition position);
   Node* ArrayLen(Node* array_object, wasm::WasmCodePosition position);
+  Node* I31New(Node* input);
+  Node* I31GetS(Node* input);
+  Node* I31GetU(Node* input);
   Node* RttCanon(wasm::HeapType type);
   Node* RttSub(wasm::HeapType type, Node* parent_rtt);
 

src/wasm/baseline/liftoff-compiler.cc

@@ -3612,6 +3612,19 @@ class LiftoffCompiler {
     unsupported(decoder, kGC, "array.len");
   }
 
+  void I31New(FullDecoder* decoder, const Value& input, Value* result) {
+    // TODO(7748): Implement.
+    unsupported(decoder, kGC, "i31.new");
+  }
+  void I31GetS(FullDecoder* decoder, const Value& input, Value* result) {
+    // TODO(7748): Implement.
+    unsupported(decoder, kGC, "i31.get_s");
+  }
+  void I31GetU(FullDecoder* decoder, const Value& input, Value* result) {
+    // TODO(7748): Implement.
+    unsupported(decoder, kGC, "i31.get_u");
+  }
+
   void RttCanon(FullDecoder* decoder, const HeapTypeImmediate<validate>& imm,
                 Value* result) {
     // TODO(7748): Implement.

src/wasm/function-body-decoder-impl.h

@@ -159,6 +159,7 @@ ValueType read_value_type(Decoder* decoder, const byte* pc,
     REF_TYPE_CASE(Extern, kNullable, reftypes)
     REF_TYPE_CASE(Eq, kNullable, gc)
     REF_TYPE_CASE(Exn, kNullable, eh)
+    REF_TYPE_CASE(I31, kNonNullable, gc)
     case kLocalI32:
       return kWasmI32;
     case kLocalI64:
@@ -178,6 +179,7 @@ ValueType read_value_type(Decoder* decoder, const byte* pc,
         REF_TYPE_CASE(Extern, nullability, typed_funcref)
         REF_TYPE_CASE(Eq, nullability, gc)
         REF_TYPE_CASE(Exn, nullability, eh)
+        REF_TYPE_CASE(I31, nullability, gc)
         default:
           uint32_t type_index =
               decoder->read_u32v<validate>(pc + 1, length, "type index");
@@ -964,6 +966,9 @@ struct ControlBase {
     const ArrayIndexImmediate<validate>& imm, const Value& index,              \
     const Value& value)                                                        \
   F(ArrayLen, const Value& array_obj, Value* result)                           \
+  F(I31New, const Value& input, Value* result)                                 \
+  F(I31GetS, const Value& input, Value* result)                                \
+  F(I31GetU, const Value& input, Value* result)                                \
   F(RttCanon, const HeapTypeImmediate<validate>& imm, Value* result)           \
   F(RttSub, const HeapTypeImmediate<validate>& imm, const Value& parent,       \
     Value* result)                                                             \
@@ -3447,6 +3452,24 @@ class WasmFullDecoder : public WasmDecoder<validate> {
         CALL_INTERFACE_IF_REACHABLE(ArrayLen, array_obj, value);
         break;
       }
+      case kExprI31New: {
+        Value input = Pop(0, kWasmI32);
+        Value* value = Push(kWasmI31Ref);
+        CALL_INTERFACE_IF_REACHABLE(I31New, input, value);
+        break;
+      }
+      case kExprI31GetS: {
+        Value i31 = Pop(0, kWasmI31Ref);
+        Value* value = Push(kWasmI32);
+        CALL_INTERFACE_IF_REACHABLE(I31GetS, i31, value);
+        break;
+      }
+      case kExprI31GetU: {
+        Value i31 = Pop(0, kWasmI31Ref);
+        Value* value = Push(kWasmI32);
+        CALL_INTERFACE_IF_REACHABLE(I31GetU, i31, value);
+        break;
+      }
       case kExprRttCanon: {
         HeapTypeImmediate<validate> imm(this->enabled_, this, this->pc_ + 2);
         len += imm.length;

src/wasm/graph-builder-interface.cc

@@ -709,6 +709,18 @@ class WasmGraphBuildingInterface {
     result->node = BUILD(ArrayLen, array_obj.node, decoder->position());
   }
 
+  void I31New(FullDecoder* decoder, const Value& input, Value* result) {
+    result->node = BUILD(I31New, input.node);
+  }
+
+  void I31GetS(FullDecoder* decoder, const Value& input, Value* result) {
+    result->node = BUILD(I31GetS, input.node);
+  }
+
+  void I31GetU(FullDecoder* decoder, const Value& input, Value* result) {
+    result->node = BUILD(I31GetU, input.node);
+  }
+
   void RttCanon(FullDecoder* decoder, const HeapTypeImmediate<validate>& imm,
                 Value* result) {
     result->node = BUILD(RttCanon, imm.type);

src/wasm/value-type.h

@@ -49,6 +49,11 @@ class HeapType {
   static const uint32_t kExtern = kFunc + 1;      // shorthand: e
   static const uint32_t kEq = kFunc + 2;          // shorthand: q
   static const uint32_t kExn = kFunc + 3;         // shorthand: x
+  static const uint32_t kI31 = kFunc + 4;         // shorthand: j
+  // Internal use only; defined in the public section to make it easy to
+  // check that they are defined correctly:
+  static const uint32_t kFirstSentinel = kFunc;
+  static const uint32_t kLastSentinel = kI31;
 
   explicit constexpr HeapType(uint32_t type) : type_(type) {
     CONSTEXPR_DCHECK(is_valid());
@@ -67,10 +72,7 @@ class HeapType {
     return type_;
   }
 
-  constexpr bool is_generic() {
-    STATIC_ASSERT(kExtern >= kFunc && kEq >= kFunc && kExn >= kFunc);
-    return type_ >= kFunc;
-  }
+  constexpr bool is_generic() { return type_ >= kFirstSentinel; }
 
   constexpr bool is_index() { return !is_generic(); }
 
@@ -84,6 +86,8 @@ class HeapType {
         return std::string("eq");
       case kExn:
         return std::string("exn");
+      case kI31:
+        return std::string("i31");
       default:
         return std::to_string(type_);
     }
@@ -99,6 +103,8 @@ class HeapType {
         return kLocalExternRef;
       case kEq:
         return kLocalEqRef;
+      case kI31:
+        return kLocalI31Ref;
       default:
         return type_;
     }
@@ -107,10 +113,7 @@ class HeapType {
  private:
   friend class ValueType;
   uint32_t type_;
-  constexpr bool is_valid() const {
-    STATIC_ASSERT(kFunc <= kExn && kExtern <= kExn && kEq <= kExn);
-    return type_ <= kExn;
-  }
+  constexpr bool is_valid() const { return type_ <= kLastSentinel; }
 };
 enum Nullability : bool { kNonNullable, kNullable };
 
@@ -257,6 +260,7 @@ class ValueType {
             return kLocalOptRef;
         }
       case kRef:
+        if (heap() == HeapType::kI31) return kLocalI31Ref;
         return kLocalRef;
       case kStmt:
         return kLocalVoid;
@@ -274,8 +278,9 @@ class ValueType {
   }
 
   constexpr bool encoding_needs_heap_type() const {
-    return kind() == kRef || kind() == kRtt ||
-           (kind() == kOptRef && !heap_type().is_generic());
+    return (kind() == kRef && heap() != HeapType::kI31) || kind() == kRtt ||
+           (kind() == kOptRef &&
+            (!heap_type().is_generic() || heap() == HeapType::kI31));
   }
 
   static ValueType For(MachineType type) {
@@ -313,7 +318,11 @@ class ValueType {
     std::ostringstream buf;
     switch (kind()) {
       case kRef:
+        if (heap() == HeapType::kI31) {
+          buf << "i31ref";
+        } else {
           buf << "(ref " << heap_type().name() << ")";
+        }
         break;
       case kOptRef:
         if (heap_type().is_generic()) {
@@ -381,6 +390,7 @@ constexpr ValueType kWasmExnRef = ValueType::Ref(HeapType::kExn, kNullable);
 constexpr ValueType kWasmExternRef =
     ValueType::Ref(HeapType::kExtern, kNullable);
 constexpr ValueType kWasmEqRef = ValueType::Ref(HeapType::kEq, kNullable);
+constexpr ValueType kWasmI31Ref = ValueType::Ref(HeapType::kI31, kNonNullable);
 
 #define FOREACH_WASMVALUE_CTYPES(V) \
   V(kI32, int32_t)                  \

src/wasm/wasm-constants.h

@@ -37,7 +37,7 @@ enum ValueTypeCode : uint8_t {
   kLocalEqRef = 0x6d,
   kLocalOptRef = 0x6c,
   kLocalRef = 0x6b,
-  // kLocalI31 = 0x6a, // TODO(7748): Implement
+  kLocalI31Ref = 0x6a,
   kLocalRtt = 0x69,
   // Exception handling proposal
   kLocalExnRef = 0x68,

test/cctest/wasm/test-gc.cc

@@ -36,10 +36,10 @@ class WasmGCTester {
                        true),
         zone(&allocator, ZONE_NAME),
         builder(&zone),
-        isolate(CcTest::InitIsolateOnce()),
-        scope(isolate),
-        thrower(isolate, "Test wasm GC") {
-    testing::SetupIsolateForWasmModule(isolate);
+        isolate_(CcTest::InitIsolateOnce()),
+        scope(isolate_),
+        thrower(isolate_, "Test wasm GC") {
+    testing::SetupIsolateForWasmModule(isolate_);
   }
 
   uint32_t AddGlobal(ValueType type, bool mutability, WasmInitExpr init) {
@@ -76,7 +76,7 @@ class WasmGCTester {
     builder.WriteTo(&buffer);
     MaybeHandle<WasmInstanceObject> maybe_instance =
         testing::CompileAndInstantiateForTesting(
-            isolate, &thrower, ModuleWireBytes(buffer.begin(), buffer.end()));
+            isolate_, &thrower, ModuleWireBytes(buffer.begin(), buffer.end()));
     if (thrower.error()) FATAL("%s", thrower.error_msg());
     instance_ = maybe_instance.ToHandleChecked();
   }
@@ -86,10 +86,10 @@ class WasmGCTester {
     Handle<Object>* argv = zone.NewArray<Handle<Object>>(args.size());
     int i = 0;
     for (Object arg : args) {
-      argv[i++] = handle(arg, isolate);
+      argv[i++] = handle(arg, isolate_);
     }
     CHECK_EQ(expected, testing::CallWasmFunctionForTesting(
-                           isolate, instance_, &thrower, function,
+                           isolate_, instance_, &thrower, function,
                            static_cast<uint32_t>(args.size()), argv));
   }
 
@@ -101,26 +101,27 @@ class WasmGCTester {
     Handle<Object>* argv = zone.NewArray<Handle<Object>>(args.size());
     int i = 0;
     for (Object arg : args) {
-      argv[i++] = handle(arg, isolate);
+      argv[i++] = handle(arg, isolate_);
     }
     Handle<WasmExportedFunction> exported =
-        testing::GetExportedFunction(isolate, instance_, function)
+        testing::GetExportedFunction(isolate_, instance_, function)
             .ToHandleChecked();
-    return Execution::Call(isolate, exported,
-                           isolate->factory()->undefined_value(),
+    return Execution::Call(isolate_, exported,
+                           isolate_->factory()->undefined_value(),
                            static_cast<uint32_t>(args.size()), argv);
   }
 
   void CheckHasThrown(const char* function,
                       std::initializer_list<Object> args) {
-    TryCatch try_catch(reinterpret_cast<v8::Isolate*>(isolate));
+    TryCatch try_catch(reinterpret_cast<v8::Isolate*>(isolate_));
     MaybeHandle<Object> result = GetJSResult(function, args);
     CHECK(result.is_null());
     CHECK(try_catch.HasCaught());
-    isolate->clear_pending_exception();
+    isolate_->clear_pending_exception();
   }
 
   Handle<WasmInstanceObject> instance() { return instance_; }
+  Isolate* isolate() { return isolate_; }
 
   TestSignatures sigs;
 
@@ -133,7 +134,7 @@ class WasmGCTester {
   Zone zone;
   WasmModuleBuilder builder;
 
-  Isolate* const isolate;
+  Isolate* const isolate_;
   const HandleScope scope;
   Handle<WasmInstanceObject> instance_;
   ErrorThrower thrower;
@@ -581,6 +582,34 @@ TEST(BasicRTT) {
            submap->wasm_type_info().foreign_address());
 }
 
+TEST(BasicI31) {
+  WasmGCTester tester;
+  tester.DefineFunction(
+      "f", tester.sigs.i_i(), {},
+      {WASM_I31_GET_S(WASM_I31_NEW(WASM_GET_LOCAL(0))), kExprEnd});
+  tester.DefineFunction(
+      "g", tester.sigs.i_i(), {},
+      {WASM_I31_GET_U(WASM_I31_NEW(WASM_GET_LOCAL(0))), kExprEnd});
+  // TODO(7748): Support (rtt.canon i31), and add a test like:
+  // (ref.test (i31.new ...) (rtt.canon i31)).
+  tester.CompileModule();
+  tester.CheckResult("f", 123, {Smi::FromInt(123)});
+  tester.CheckResult("g", 123, {Smi::FromInt(123)});
+  // Truncation:
+  tester.CheckResult(
+      "f", 0x1234,
+      {*tester.isolate()->factory()->NewNumberFromUint(0x80001234)});
+  tester.CheckResult(
+      "g", 0x1234,
+      {*tester.isolate()->factory()->NewNumberFromUint(0x80001234)});
+  // Sign/zero extension:
+  tester.CheckResult(
+      "f", -1, {*tester.isolate()->factory()->NewNumberFromUint(0x7FFFFFFF)});
+  tester.CheckResult(
+      "g", 0x7FFFFFFF,
+      {*tester.isolate()->factory()->NewNumberFromUint(0x7FFFFFFF)});
+}
+
 }  // namespace test_gc
 }  // namespace wasm
 }  // namespace internal

test/common/wasm/wasm-macro-gen.h

@@ -462,6 +462,10 @@ inline WasmOpcode LoadStoreOpcodeOf(MachineType type, bool store) {
 #define WASM_RTT_SUB(typeidx) \
   WASM_GC_OP(kExprRttSub), static_cast<byte>(typeidx)
 
+#define WASM_I31_NEW(val) val, WASM_GC_OP(kExprI31New)
+#define WASM_I31_GET_S(val) val, WASM_GC_OP(kExprI31GetS)
+#define WASM_I31_GET_U(val) val, WASM_GC_OP(kExprI31GetU)
+
 #define WASM_BR_ON_NULL(depth, ref_object) \
   ref_object, kExprBrOnNull, static_cast<byte>(depth)
 // Pass: sig_index, ...args, func_index