From 1d8dde36e166db5b62ef08d0dab0031dae0148f3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=96mer=20Sinan=20A=C4=9Facan?= <omersa@google.com>
Date: Mon, 17 Jul 2023 16:51:25 +0000
Subject: [PATCH] [dart2wasm] Add array.copy instruction and intrinsics
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`array.copy` is used in [1] in `setRange` when source and destinations
are both typed arrays with the same Wasm array type.

[1]: https://dart-review.googlesource.com/c/sdk/+/312907

Change-Id: Iaeecea43c22805eca64b7d98751a52e607210a70
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/314080
Reviewed-by: Joshua Litt <joshualitt@google.com>
Commit-Queue: Ömer Ağacan <omersa@google.com>
---
 pkg/dart2wasm/lib/intrinsics.dart          | 28 ++++++++++++++++++++--
 pkg/wasm_builder/lib/src/instructions.dart | 17 +++++++++++++
 sdk/lib/_wasm/wasm_types.dart              |  4 ++++
 3 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/pkg/dart2wasm/lib/intrinsics.dart b/pkg/dart2wasm/lib/intrinsics.dart
index fa0f763d03f..7e0fa32e042 100644
--- a/pkg/dart2wasm/lib/intrinsics.dart
+++ b/pkg/dart2wasm/lib/intrinsics.dart
@@ -410,11 +410,35 @@ class Intrinsifier {
           }
           b.array_set(arrayType);
           return codeGen.voidMarker;
-        default:
-          throw "Unsupported array method: $name";
       }
     }
 
+    // WasmIntArray.copy
+    // WasmFloatArray.copy
+    if (cls.superclass == translator.wasmArrayRefClass && name == 'copy') {
+      final DartType elementType =
+          (receiverType as InterfaceType).typeArguments.single;
+      final w.ArrayType arrayType =
+          translator.arrayTypeForDartType(elementType);
+
+      final Expression destArray = receiver;
+      final Expression destOffset = node.arguments.positional[0];
+      final Expression sourceArray = node.arguments.positional[1];
+      final Expression sourceOffset = node.arguments.positional[2];
+      final Expression size = node.arguments.positional[3];
+
+      codeGen.wrap(destArray, w.RefType.def(arrayType, nullable: false));
+      codeGen.wrap(destOffset, w.NumType.i64);
+      b.i32_wrap_i64();
+      codeGen.wrap(sourceArray, w.RefType.def(arrayType, nullable: false));
+      codeGen.wrap(sourceOffset, w.NumType.i64);
+      b.i32_wrap_i64();
+      codeGen.wrap(size, w.NumType.i64);
+      b.i32_wrap_i64();
+      b.array_copy(arrayType, arrayType);
+      return codeGen.voidMarker;
+    }
+
     // Wasm(I32|I64|F32|F64) conversions
     if (cls.superclass?.superclass == translator.wasmTypesBaseClass) {
       w.StorageType receiverType = translator.builtinTypes[cls]!;
diff --git a/pkg/wasm_builder/lib/src/instructions.dart b/pkg/wasm_builder/lib/src/instructions.dart
index e0d78eb4400..f2027dc67d2 100644
--- a/pkg/wasm_builder/lib/src/instructions.dart
+++ b/pkg/wasm_builder/lib/src/instructions.dart
@@ -1111,6 +1111,23 @@ class Instructions with SerializerMixin {
     if (isGlobalInitializer) module.dataReferencedFromGlobalInitializer = true;
   }
 
+  void array_copy(ArrayType destArrayType, ArrayType sourceArrayType) {
+    assert(_verifyTypes([
+      RefType.def(destArrayType, nullable: true), // dest
+      NumType.i32, // dest_offset
+      RefType.def(sourceArrayType, nullable: true), // source
+      NumType.i32, // source_offset
+      NumType.i32 // size
+    ], [], trace: [
+      'array.copy',
+      destArrayType,
+      sourceArrayType
+    ]));
+    writeBytes(const [0xFB, 0x18]);
+    writeUnsigned(destArrayType.index);
+    writeUnsigned(sourceArrayType.index);
+  }
+
   /// Emit an `i31.new` instruction.
   void i31_new() {
     assert(_verifyTypes(
diff --git a/sdk/lib/_wasm/wasm_types.dart b/sdk/lib/_wasm/wasm_types.dart
index 91d00605426..6d3432a61f8 100644
--- a/sdk/lib/_wasm/wasm_types.dart
+++ b/sdk/lib/_wasm/wasm_types.dart
@@ -180,6 +180,8 @@ class WasmIntArray<T extends _WasmInt> extends WasmArrayRef {
   external int readSigned(int index);
   external int readUnsigned(int index);
   external void write(int index, int value);
+  external void copy(
+      int offset, WasmIntArray<T> source, int sourceOffset, int size);
 }
 
 /// A Wasm array with float element type.
@@ -189,6 +191,8 @@ class WasmFloatArray<T extends _WasmFloat> extends WasmArrayRef {
 
   external double read(int index);
   external void write(int index, double value);
+  external void copy(
+      int offset, WasmFloatArray<T> source, int sourceOffset, int size);
 }
 
 /// A Wasm array with reference element type, containing Dart objects.