Added memory grow notification system.

Author: flohuemer

wasm/src/org.graalvm.wasm/src/org/graalvm/wasm/api/WebAssembly.java

@@ -101,6 +101,7 @@ public WebAssembly(WasmContext currentContext) {
 
         addMember("mem_alloc", new Executable(args -> memAlloc(args)));
         addMember("mem_grow", new Executable(args -> memGrow(args)));
+        addMember("mem_set_grow_callback", new Executable(args -> memSetGrowCallback(args)));
 
         addMember("global_alloc", new Executable(args -> globalAlloc(args)));
         addMember("global_read", new Executable(args -> globalRead(args)));
@@ -583,6 +584,35 @@ public static long memGrow(WasmMemory memory, int delta) {
         return pageSize;
     }
 
+    private static Object memSetGrowCallback(Object[] args) {
+        InteropLibrary lib = InteropLibrary.getUncached();
+        if (!(args[0] instanceof WasmMemory)) {
+            throw new WasmJsApiException(WasmJsApiException.Kind.TypeError, "First argument must be wasm memory");
+        }
+        if (!lib.isExecutable(args[1])) {
+            throw new WasmJsApiException(WasmJsApiException.Kind.TypeError, "Second argument must be executable");
+        }
+        WasmMemory memory = (WasmMemory) args[0];
+        return memSetGrowCallback(memory, args[1]);
+    }
+
+    private static Object memSetGrowCallback(WasmMemory memory, Object callback) {
+        memory.setGrowCallback(callback);
+        return WasmVoidResult.getInstance();
+    }
+
+    public static void invokeMemGrowCallback(WasmMemory memory) {
+        Object callback = memory.getGrowCallback();
+        if (callback != null) {
+            InteropLibrary lib = InteropLibrary.getUncached();
+            try {
+                lib.execute(callback, memory);
+            } catch (InteropException e) {
+                throw new WasmJsApiException(WasmJsApiException.Kind.TypeError, "Unable to call memory grow callback", e);
+            }
+        }
+    }
+
     private static Object globalAlloc(Object[] args) {
         checkArgumentCount(args, 3);
 

wasm/src/org.graalvm.wasm/src/org/graalvm/wasm/memory/ByteArrayWasmMemory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2020, 2021, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * The Universal Permissive License (UPL), Version 1.0
@@ -146,6 +146,7 @@ public int declaredMaxSize() {
     @TruffleBoundary
     public synchronized boolean grow(int extraPageSize) {
         if (extraPageSize == 0) {
+            invokeGrowCallback();
             return true;
         } else if (compareUnsigned(extraPageSize, maxAllowedSize) <= 0 && compareUnsigned(size() + extraPageSize, maxAllowedSize) <= 0) {
             try {
@@ -155,6 +156,7 @@ public synchronized boolean grow(int extraPageSize) {
                 final byte[] newBuffer = new byte[targetByteSize];
                 System.arraycopy(buffer, 0, newBuffer, 0, buffer.length);
                 buffer = newBuffer;
+                invokeGrowCallback();
                 return true;
             } catch (OutOfMemoryError error) {
                 throw WasmException.create(Failure.MEMORY_ALLOCATION_FAILED);

wasm/src/org.graalvm.wasm/src/org/graalvm/wasm/memory/UnsafeWasmMemory.java

@@ -159,6 +159,7 @@ public int declaredMaxSize() {
     @TruffleBoundary
     public boolean grow(int extraPageSize) {
         if (extraPageSize == 0) {
+            invokeGrowCallback();
             return true;
         } else if (compareUnsigned(extraPageSize, maxAllowedSize) <= 0 && compareUnsigned(size() + extraPageSize, maxAllowedSize) <= 0) {
             // Condition above and limit on maxPageSize (see ModuleLimits#MAX_MEMORY_SIZE) ensure
@@ -171,6 +172,7 @@ public boolean grow(int extraPageSize) {
                 unsafe.freeMemory(startAddress);
                 startAddress = updatedStartAddress;
                 size += extraPageSize;
+                invokeGrowCallback();
                 return true;
             } catch (OutOfMemoryError error) {
                 throw WasmException.create(Failure.MEMORY_ALLOCATION_FAILED);

wasm/src/org.graalvm.wasm/src/org/graalvm/wasm/memory/WasmMemory.java

@@ -64,10 +64,13 @@
 import com.oracle.truffle.api.library.ExportMessage;
 import com.oracle.truffle.api.nodes.Node;
 import com.oracle.truffle.api.profiles.BranchProfile;
+import org.graalvm.wasm.api.WebAssembly;
 
 @ExportLibrary(InteropLibrary.class)
 public abstract class WasmMemory implements TruffleObject {
 
+    private Object growCallback = null;
+
     public abstract void copy(Node node, int src, int dst, int n);
 
     /**
@@ -489,4 +492,16 @@ public void writeArrayElement(long address, Object value,
         }
         store_i32_8(null, (int) address, rawValue);
     }
+
+    public void setGrowCallback(Object growCallback) {
+        this.growCallback = growCallback;
+    }
+
+    public Object getGrowCallback() {
+        return growCallback;
+    }
+
+    protected void invokeGrowCallback() {
+        WebAssembly.invokeMemGrowCallback(this);
+    }
 }