deps: V8: cherry-pick bc831f8ba33b

common.gypi

@@ -36,7 +36,7 @@
 
     # Reset this number to 0 on major V8 upgrades.
     # Increment by one for each non-official patch applied to deps/v8.
-    'v8_embedder_string': '-node.5',
+    'v8_embedder_string': '-node.6',
 
     ##### V8 defaults for Node.js #####
 

deps/v8/include/v8-fast-api-calls.h

@@ -248,6 +248,7 @@ class CTypeInfo {
     kFloat32,
     kFloat64,
     kV8Value,
+    kSeqOneByteString,
     kApiObject,  // This will be deprecated once all users have
                  // migrated from v8::ApiObject to v8::Local<v8::Value>.
     kAny,        // This is added to enable untyped representation of fast
@@ -379,6 +380,11 @@ struct FastApiArrayBuffer {
   size_t byte_length;
 };
 
+struct FastOneByteString {
+  const char* data;
+  uint32_t length;
+};
+
 class V8_EXPORT CFunctionInfo {
  public:
   // Construct a struct to hold a CFunction's type information.
@@ -438,6 +444,7 @@ struct AnyCType {
     const FastApiTypedArray<uint64_t>* uint64_ta_value;
     const FastApiTypedArray<float>* float_ta_value;
     const FastApiTypedArray<double>* double_ta_value;
+    const FastOneByteString* string_value;
     FastApiCallbackOptions* options_value;
   };
 };
@@ -614,7 +621,7 @@ class CFunctionInfoImpl : public CFunctionInfo {
                       kReturnType == CTypeInfo::Type::kFloat32 ||
                       kReturnType == CTypeInfo::Type::kFloat64 ||
                       kReturnType == CTypeInfo::Type::kAny,
-                  "64-bit int and api object values are not currently "
+                  "64-bit int, string and api object values are not currently "
                   "supported return types.");
   }
 
@@ -735,6 +742,18 @@ struct TypeInfoHelper<FastApiCallbackOptions&> {
   }
 };
 
+template <>
+struct TypeInfoHelper<const FastOneByteString&> {
+  static constexpr CTypeInfo::Flags Flags() { return CTypeInfo::Flags::kNone; }
+
+  static constexpr CTypeInfo::Type Type() {
+    return CTypeInfo::Type::kSeqOneByteString;
+  }
+  static constexpr CTypeInfo::SequenceType SequenceType() {
+    return CTypeInfo::SequenceType::kScalar;
+  }
+};
+
 #define STATIC_ASSERT_IMPLIES(COND, ASSERTION, MSG) \
   static_assert(((COND) == 0) || (ASSERTION), MSG)
 

deps/v8/src/codegen/machine-type.h

@@ -315,6 +315,7 @@ class MachineType {
       case CTypeInfo::Type::kFloat64:
         return MachineType::Float64();
       case CTypeInfo::Type::kV8Value:
+      case CTypeInfo::Type::kSeqOneByteString:
       case CTypeInfo::Type::kApiObject:
         return MachineType::AnyTagged();
     }

deps/v8/src/compiler/effect-control-linearizer.cc

@@ -5395,6 +5395,50 @@ Node* EffectControlLinearizer::AdaptFastCallArgument(
           case CTypeInfo::Type::kFloat32: {
             return __ TruncateFloat64ToFloat32(node);
           }
+          case CTypeInfo::Type::kSeqOneByteString: {
+            // Check that the value is a HeapObject.
+            Node* value_is_smi = ObjectIsSmi(node);
+            __ GotoIf(value_is_smi, if_error);
+
+            Node* map = __ LoadField(AccessBuilder::ForMap(), node);
+            Node* instance_type =
+                __ LoadField(AccessBuilder::ForMapInstanceType(), map);
+
+            Node* encoding = __ Word32And(
+                instance_type,
+                __ Int32Constant(kStringRepresentationAndEncodingMask));
+
+            Node* is_onebytestring = __ Word32Equal(
+                encoding, __ Int32Constant(kSeqOneByteStringTag));
+            __ GotoIfNot(is_onebytestring, if_error);
+
+            Node* length_in_bytes =
+                __ LoadField(AccessBuilder::ForStringLength(), node);
+            Node* data_ptr = __ IntPtrAdd(
+                node, __ IntPtrConstant(SeqOneByteString::kHeaderSize -
+                                        kHeapObjectTag));
+
+            constexpr int kAlign = alignof(FastOneByteString);
+            constexpr int kSize = sizeof(FastOneByteString);
+            static_assert(kSize == sizeof(uintptr_t) + sizeof(size_t),
+                          "The size of "
+                          "FastOneByteString isn't equal to the sum of its "
+                          "expected members.");
+            Node* stack_slot = __ StackSlot(kSize, kAlign);
+
+            __ Store(StoreRepresentation(MachineType::PointerRepresentation(),
+                                         kNoWriteBarrier),
+                     stack_slot, 0, data_ptr);
+            __ Store(StoreRepresentation(MachineRepresentation::kWord32,
+                                         kNoWriteBarrier),
+                     stack_slot, sizeof(size_t), length_in_bytes);
+
+            static_assert(sizeof(uintptr_t) == sizeof(size_t),
+                          "The string length can't "
+                          "fit the PointerRepresentation used to store it.");
+
+            return stack_slot;
+          }
           default: {
             return node;
           }
@@ -5600,6 +5644,7 @@ Node* EffectControlLinearizer::LowerFastApiCall(Node* node) {
           case CTypeInfo::Type::kFloat64:
             return ChangeFloat64ToTagged(
                 c_call_result, CheckForMinusZeroMode::kCheckForMinusZero);
+          case CTypeInfo::Type::kSeqOneByteString:
           case CTypeInfo::Type::kV8Value:
           case CTypeInfo::Type::kApiObject:
           case CTypeInfo::Type::kUint8:

deps/v8/src/compiler/fast-api-calls.cc

@@ -29,6 +29,7 @@ ElementsKind GetTypedArrayElementsKind(CTypeInfo::Type type) {
     case CTypeInfo::Type::kFloat64:
       return FLOAT64_ELEMENTS;
     case CTypeInfo::Type::kVoid:
+    case CTypeInfo::Type::kSeqOneByteString:
     case CTypeInfo::Type::kBool:
     case CTypeInfo::Type::kV8Value:
     case CTypeInfo::Type::kApiObject:

deps/v8/src/compiler/simplified-lowering.cc

@@ -1961,6 +1961,7 @@ class RepresentationSelector {
           case CTypeInfo::Type::kFloat64:
             return UseInfo::CheckedNumberAsFloat64(kDistinguishZeros, feedback);
           case CTypeInfo::Type::kV8Value:
+          case CTypeInfo::Type::kSeqOneByteString:
           case CTypeInfo::Type::kApiObject:
             return UseInfo::AnyTagged();
         }

deps/v8/src/d8/d8-test.cc

@@ -42,6 +42,43 @@ class FastCApiObject {
  public:
   static FastCApiObject& instance();
 
+#ifdef V8_USE_SIMULATOR_WITH_GENERIC_C_CALLS
+  static AnyCType CopyStringFastCallbackPatch(AnyCType receiver,
+                                              AnyCType should_fallback,
+                                              AnyCType source, AnyCType out,
+                                              AnyCType options) {
+    AnyCType ret;
+    CopyStringFastCallback(receiver.object_value, should_fallback.bool_value,
+                           *source.string_value, *out.uint8_ta_value,
+                           *options.options_value);
+    return ret;
+  }
+
+#endif  //  V8_USE_SIMULATOR_WITH_GENERIC_C_CALLS
+  static void CopyStringFastCallback(Local<Object> receiver,
+                                     bool should_fallback,
+                                     const FastOneByteString& source,
+                                     const FastApiTypedArray<uint8_t>& out,
+                                     FastApiCallbackOptions& options) {
+    FastCApiObject* self = UnwrapObject(receiver);
+    self->fast_call_count_++;
+
+    if (should_fallback) {
+      options.fallback = true;
+    } else {
+      options.fallback = false;
+    }
+
+    uint8_t* memory = nullptr;
+    CHECK(out.getStorageIfAligned(&memory));
+    memcpy(memory, source.data, source.length);
+  }
+
+  static void CopyStringSlowCallback(const FunctionCallbackInfo<Value>& args) {
+    FastCApiObject* self = UnwrapObject(args.This());
+    CHECK_SELF_OR_THROW();
+    self->slow_call_count_++;
+  }
 #ifdef V8_USE_SIMULATOR_WITH_GENERIC_C_CALLS
   static AnyCType AddAllFastCallbackPatch(AnyCType receiver,
                                           AnyCType should_fallback,
@@ -1084,6 +1121,16 @@ Local<FunctionTemplate> Shell::CreateTestFastCApiTemplate(Isolate* isolate) {
   PerIsolateData::Get(isolate)->SetTestApiObjectCtor(api_obj_ctor);
   Local<Signature> signature = Signature::New(isolate, api_obj_ctor);
   {
+    CFunction copy_str_func = CFunction::Make(
+        FastCApiObject::CopyStringFastCallback V8_IF_USE_SIMULATOR(
+            FastCApiObject::CopyStringFastCallbackPatch));
+    api_obj_ctor->PrototypeTemplate()->Set(
+        isolate, "copy_string",
+        FunctionTemplate::New(isolate, FastCApiObject::CopyStringSlowCallback,
+                              Local<Value>(), signature, 1,
+                              ConstructorBehavior::kThrow,
+                              SideEffectType::kHasSideEffect, &copy_str_func));
+
     CFunction add_all_c_func =
         CFunction::Make(FastCApiObject::AddAllFastCallback V8_IF_USE_SIMULATOR(
             FastCApiObject::AddAllFastCallbackPatch));

deps/v8/test/mjsunit/compiler/fast-api-calls-string.js

@@ -0,0 +1,84 @@
+// Copyright 2022 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// This file excercises one byte string support for fast API calls.
+
+// Flags: --turbo-fast-api-calls --expose-fast-api --allow-natives-syntax --turbofan
+// --always-turbofan is disabled because we rely on particular feedback for
+// optimizing to the fastest path.
+// Flags: --no-always-turbofan
+// The test relies on optimizing/deoptimizing at predictable moments, so
+// it's not suitable for deoptimization fuzzing.
+// Flags: --deopt-every-n-times=0
+
+assertThrows(() => d8.test.FastCAPI());
+const fast_c_api = new d8.test.FastCAPI();
+
+function assertSlowCall(input) {
+  assertEquals(new Uint8Array(input.length), copy_string(false, input));
+}
+
+function assertFastCall(input) {
+  const bytes = Uint8Array.from(input, c => c.charCodeAt(0));
+  assertEquals(bytes, copy_string(false, input));
+}
+
+function copy_string(should_fallback = false, input) {
+  const buffer = new Uint8Array(input.length);
+  fast_c_api.copy_string(should_fallback, input, buffer);
+  return buffer;
+}
+
+%PrepareFunctionForOptimization(copy_string);
+assertSlowCall('Hello');
+%OptimizeFunctionOnNextCall(copy_string);
+
+fast_c_api.reset_counts();
+assertFastCall('Hello');
+assertFastCall('');
+assertFastCall(['Hello', 'World'].join(''));
+assertOptimized(copy_string);
+assertEquals(3, fast_c_api.fast_call_count());
+assertEquals(0, fast_c_api.slow_call_count());
+
+// Fall back for twobyte strings.
+fast_c_api.reset_counts();
+assertSlowCall('Hello\u{10000}');
+assertSlowCall('नमस्ते');
+assertSlowCall(['नमस्ते', 'World'].join(''));
+assertOptimized(copy_string);
+assertEquals(0, fast_c_api.fast_call_count());
+assertEquals(3, fast_c_api.slow_call_count());
+
+// Fall back for cons strings.
+function getTwoByteString() {
+  return '\u1234t';
+}
+function getCons() {
+  return 'hello' + getTwoByteString()
+}
+
+fast_c_api.reset_counts();
+assertSlowCall(getCons());
+assertOptimized(copy_string);
+assertEquals(0, fast_c_api.fast_call_count());
+assertEquals(1, fast_c_api.slow_call_count());
+
+// Fall back for sliced strings.
+fast_c_api.reset_counts();
+function getSliced() {
+  return getCons().slice(1);
+}
+assertSlowCall(getSliced());
+assertOptimized(copy_string);
+assertEquals(0, fast_c_api.fast_call_count());
+assertEquals(1, fast_c_api.slow_call_count());
+
+// Fall back for SMI and non-string inputs.
+fast_c_api.reset_counts();
+assertSlowCall(1);
+assertSlowCall({});
+assertSlowCall(new Uint8Array(1));
+assertEquals(0, fast_c_api.fast_call_count());
+assertEquals(3, fast_c_api.slow_call_count());