Support table imports

5 files changed, 55 insertions, 2 deletions

diff --git a/src/main/java/org/shedlang/compiler/backends/wasm/structure/WasmBinaryFormat.java b/src/main/java/org/shedlang/compiler/backends/wasm/structure/WasmBinaryFormat.java
index 2ac60424..430e1ab4 100644
--- a/src/main/java/org/shedlang/compiler/backends/wasm/structure/WasmBinaryFormat.java
+++ b/src/main/java/org/shedlang/compiler/backends/wasm/structure/WasmBinaryFormat.java
@@ -4,8 +4,7 @@ import org.pcollections.PVector;
 import org.shedlang.compiler.backends.wasm.structure.ast.WasmModule;
 import org.shedlang.compiler.backends.wasm.structure.ast.imports.WasmImport;
 import org.shedlang.compiler.backends.wasm.structure.ast.imports.WasmImportDescriptor;
-import org.shedlang.compiler.backends.wasm.structure.ast.types.WasmFuncType;
-import org.shedlang.compiler.backends.wasm.structure.ast.types.WasmValueType;
+import org.shedlang.compiler.backends.wasm.structure.ast.types.*;
 
 import java.io.IOException;
 import java.io.OutputStream;
@@ -102,6 +101,10 @@ public class WasmBinaryFormat {
                 var typeIndex = funcTypeToTypeIndex.get(func.type());
                 writeTypeIndex(typeIndex, writer);
             }
+            case WasmImportDescriptor.Table table -> {
+                writer.writeByte(0x01);
+                writeTableType(table.type(), writer);
+            }
         }
     }
 
@@ -119,6 +122,7 @@ public class WasmBinaryFormat {
             var importedFunctions = module.imports().stream()
                 .flatMap(import_ -> switch (import_.descriptor()) {
                     case WasmImportDescriptor.Func func -> Stream.of(func);
+                    default -> Stream.empty();
                 })
                 .toList();
 
@@ -147,6 +151,19 @@ public class WasmBinaryFormat {
         writeValueTypeVector(type.results(), writer);
     }
 
+    private static void writeReferenceType(WasmReferenceType type, BinaryWriter writer) {
+        var encoding = switch (type) {
+            case FUNC_REF -> 0x70;
+            case EXTERN_REF -> 0x6f;
+        };
+        writer.writeByte(encoding);
+    }
+
+    private static void writeTableType(WasmTableType type, BinaryWriter writer) {
+        writeReferenceType(type.elementType(), writer);
+        writeLimits(type.limits(), writer);
+    }
+
     private static void writeValueTypeVector(List<WasmValueType> types, BinaryWriter writer) throws IOException {
         writeVec(
             types,
@@ -165,6 +182,17 @@ public class WasmBinaryFormat {
         writer.writeByte((byte) encoding);
     }
 
+    private static void writeLimits(WasmLimits limits, BinaryWriter writer) {
+        if (limits.max().isPresent()) {
+            writer.writeByte(0x01);
+            Leb128Encoding.encodeUnsignedInt32(limits.min(), writer);
+            Leb128Encoding.encodeUnsignedInt32(limits.max().getAsInt(), writer);
+        } else {
+            writer.writeByte(0x00);
+            Leb128Encoding.encodeUnsignedInt32(limits.min(), writer);
+        }
+    }
+
     interface Write {
         void write() throws IOException;
     }
diff --git a/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/imports/WasmImportDescriptor.java b/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/imports/WasmImportDescriptor.java
index 7b095863..db0ec936 100644
--- a/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/imports/WasmImportDescriptor.java
+++ b/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/imports/WasmImportDescriptor.java
@@ -1,7 +1,9 @@
 package org.shedlang.compiler.backends.wasm.structure.ast.imports;
 
 import org.shedlang.compiler.backends.wasm.structure.ast.types.WasmFuncType;
+import org.shedlang.compiler.backends.wasm.structure.ast.types.WasmTableType;
 
 public sealed interface WasmImportDescriptor {
     record Func(String identifier, WasmFuncType type) implements WasmImportDescriptor {}
+    record Table(WasmTableType type) implements WasmImportDescriptor {}
 }
diff --git a/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/types/WasmLimits.java b/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/types/WasmLimits.java
new file mode 100644
index 00000000..722299b9
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/types/WasmLimits.java
@@ -0,0 +1,13 @@
+package org.shedlang.compiler.backends.wasm.structure.ast.types;
+
+import java.util.OptionalInt;
+
+public record WasmLimits(int min, OptionalInt max) {
+    public static WasmLimits min(int min) {
+        return new WasmLimits(min, OptionalInt.empty());
+    }
+
+    public static WasmLimits range(int min, int max) {
+        return new WasmLimits(min, OptionalInt.of(max));
+    }
+}
diff --git a/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/types/WasmReferenceType.java b/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/types/WasmReferenceType.java
new file mode 100644
index 00000000..0bcc5ae2
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/types/WasmReferenceType.java
@@ -0,0 +1,6 @@
+package org.shedlang.compiler.backends.wasm.structure.ast.types;
+
+public enum WasmReferenceType {
+    FUNC_REF,
+    EXTERN_REF,
+}
diff --git a/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/types/WasmTableType.java b/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/types/WasmTableType.java
new file mode 100644
index 00000000..fc609808
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/types/WasmTableType.java
@@ -0,0 +1,4 @@
+package org.shedlang.compiler.backends.wasm.structure.ast.types;
+
+public record WasmTableType(WasmReferenceType elementType, WasmLimits limits) {
+}