Use explicit indirect function table

8 files changed, 75 insertions, 18 deletions

diff --git a/src/main/java/org/shedlang/compiler/backends/wasm/PatioToWasm.java b/src/main/java/org/shedlang/compiler/backends/wasm/PatioToWasm.java
index 20ddbc4c..978fe6cf 100644
--- a/src/main/java/org/shedlang/compiler/backends/wasm/PatioToWasm.java
+++ b/src/main/java/org/shedlang/compiler/backends/wasm/PatioToWasm.java
@@ -6,8 +6,7 @@ import org.pcollections.PVector;
 import org.shedlang.compiler.backends.wasm.structure.ast.instructions.*;
 import org.shedlang.compiler.backends.wasm.structure.ast.linking.WasmMemoryAddress;
 import org.shedlang.compiler.backends.wasm.structure.ast.modules.*;
-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 org.shedlang.compiler.patio.*;
 import org.shedlang.compiler.patio.instructions.*;
 import org.shedlang.compiler.patio.operands.*;
@@ -22,11 +21,22 @@ import java.util.ArrayList;
 import java.util.List;
 
 public class PatioToWasm {
+    private static final String INDIRECT_FUNCTION_TABLE_NAME = "__indirect_function_table";
+
     public static WasmModule generateCompilationUnit(
         PatioCompilationUnit patioCompilationUnit,
         WasmTarget target
     ) {
-        var module = WasmModule.EMPTY;
+        var module = WasmModule.EMPTY.addImport(
+            new WasmImport(
+                "env",
+                INDIRECT_FUNCTION_TABLE_NAME,
+                new WasmImportDescriptor.Table(
+                    INDIRECT_FUNCTION_TABLE_NAME,
+                    new WasmTableType(WasmReferenceType.FUNC_REF, WasmLimits.min32(0))
+                )
+            )
+        );
 
         var wasmMemoryBuilder = WasmMemoryBuilder.empty(target.indexType());
 
@@ -184,8 +194,7 @@ public class PatioToWasm {
                 context = context.addType(wasmFuncType);
 
                 context = context.addInstruction(new WasmCallIndirect(
-                    // TODO: remove hard-coded zero
-                    new WasmTableIndex(0),
+                    new WasmTableName(INDIRECT_FUNCTION_TABLE_NAME),
                     wasmFuncType
                 ));
 
diff --git a/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/instructions/WasmCallIndirect.java b/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/instructions/WasmCallIndirect.java
index 716aa04c..56bc5205 100644
--- a/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/instructions/WasmCallIndirect.java
+++ b/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/instructions/WasmCallIndirect.java
@@ -1,10 +1,10 @@
 package org.shedlang.compiler.backends.wasm.structure.ast.instructions;
 
-import org.shedlang.compiler.backends.wasm.structure.ast.modules.WasmTableIndex;
+import org.shedlang.compiler.backends.wasm.structure.ast.modules.WasmTableName;
 import org.shedlang.compiler.backends.wasm.structure.ast.types.WasmFuncType;
 
 public record WasmCallIndirect(
-    WasmTableIndex tableIndex,
+    WasmTableName tableName,
     WasmFuncType funcType
 ) implements WasmInstruction {
 }
diff --git a/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/linking/WasmRelocatableIndex.java b/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/linking/WasmRelocatableIndex.java
index e8da5a63..035fb998 100644
--- a/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/linking/WasmRelocatableIndex.java
+++ b/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/linking/WasmRelocatableIndex.java
@@ -2,6 +2,7 @@ package org.shedlang.compiler.backends.wasm.structure.ast.linking;
 
 import org.shedlang.compiler.backends.wasm.structure.ast.modules.WasmFuncName;
 import org.shedlang.compiler.backends.wasm.structure.ast.modules.WasmGlobalName;
+import org.shedlang.compiler.backends.wasm.structure.ast.modules.WasmTableName;
 import org.shedlang.compiler.backends.wasm.structure.ast.modules.WasmTagName;
 import org.shedlang.compiler.backends.wasm.structure.ast.types.WasmFuncType;
 
@@ -9,6 +10,7 @@ public sealed interface WasmRelocatableIndex {
     record FuncIndex(WasmFuncName funcName) implements WasmRelocatableIndex {}
     record GlobalIndex(WasmGlobalName globalName) implements WasmRelocatableIndex {}
     record MemoryAddress(WasmMemoryAddress address) implements WasmRelocatableIndex {}
+    record TableIndex(WasmTableName tableName) implements WasmRelocatableIndex {}
     record TableElementIndex(WasmFuncName funcName) implements WasmRelocatableIndex {}
     record TagIndex(WasmTagName tagName) implements WasmRelocatableIndex {}
     record TypeIndex(WasmFuncType funcType) implements WasmRelocatableIndex {}
diff --git a/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/modules/WasmTableName.java b/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/modules/WasmTableName.java
new file mode 100644
index 00000000..42536446
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/modules/WasmTableName.java
@@ -0,0 +1,4 @@
+package org.shedlang.compiler.backends.wasm.structure.ast.modules;
+
+public record WasmTableName(String value) {
+}
diff --git a/src/main/java/org/shedlang/compiler/backends/wasm/structure/binary/WasmBinaryFormatInstructions.java b/src/main/java/org/shedlang/compiler/backends/wasm/structure/binary/WasmBinaryFormatInstructions.java
index af551003..3a712e33 100644
--- a/src/main/java/org/shedlang/compiler/backends/wasm/structure/binary/WasmBinaryFormatInstructions.java
+++ b/src/main/java/org/shedlang/compiler/backends/wasm/structure/binary/WasmBinaryFormatInstructions.java
@@ -74,7 +74,7 @@ public class WasmBinaryFormatInstructions {
             case WasmCallIndirect callIndirect -> {
                 writer.writeByte(0x11);
                 writer.writeTypeIndex(callIndirect.funcType());
-                writer.writeTableIndex(callIndirect.tableIndex());
+                writer.writeTableIndex(callIndirect.tableName());
             }
 
             // == Parametric Instructions ==
diff --git a/src/main/java/org/shedlang/compiler/backends/wasm/structure/binary/WasmBinaryFormatLinking.java b/src/main/java/org/shedlang/compiler/backends/wasm/structure/binary/WasmBinaryFormatLinking.java
index fed36ed5..6b8ff4ca 100644
--- a/src/main/java/org/shedlang/compiler/backends/wasm/structure/binary/WasmBinaryFormatLinking.java
+++ b/src/main/java/org/shedlang/compiler/backends/wasm/structure/binary/WasmBinaryFormatLinking.java
@@ -80,6 +80,9 @@ public class WasmBinaryFormatLinking {
 
             case WasmRelocatableIndex.TagIndex tagIndex ->
                 symbolTable.tagNameToSymbolIndex(tagIndex.tagName()).value();
+
+            case WasmRelocatableIndex.TableIndex tableIndex ->
+                symbolTable.tableNameToSymbolIndex(tableIndex.tableName()).value();
         };
 
         writer.writeByte(relocationEntry.type().id());
@@ -249,6 +252,7 @@ public class WasmBinaryFormatLinking {
         private final Map<String, WasmSymbolIndex> funcNameToSymbolIndex;
         private final Map<String, WasmSymbolIndex> globalNameToSymbolIndex;
         private final Map<String, WasmSymbolIndex> tagNameToSymbolIndex;
+        private final Map<String, WasmSymbolIndex> tableNameToSymbolIndex;
 
         public SymbolTable(
             List<SymbolInfo> symbolInfos,
@@ -256,7 +260,8 @@ public class WasmBinaryFormatLinking {
             Map<WasmFuncType, WasmTypeIndex> funcTypeToTypeIndex,
             Map<String, WasmSymbolIndex> funcNameToSymbolIndex,
             Map<String, WasmSymbolIndex> globalNameToSymbolIndex,
-            Map<String, WasmSymbolIndex> tagNameToSymbolIndex
+            Map<String, WasmSymbolIndex> tagNameToSymbolIndex,
+            Map<String, WasmSymbolIndex> tableNameToSymbolIndex
         ) {
             this.symbolInfos = symbolInfos;
             this.memoryAddressToSymbolIndex = memoryAddressToSymbolIndex;
@@ -264,6 +269,7 @@ public class WasmBinaryFormatLinking {
             this.funcNameToSymbolIndex = funcNameToSymbolIndex;
             this.globalNameToSymbolIndex = globalNameToSymbolIndex;
             this.tagNameToSymbolIndex = tagNameToSymbolIndex;
+            this.tableNameToSymbolIndex = tableNameToSymbolIndex;
         }
 
         public WasmSymbolIndex memoryAddressToSymbolIndex(WasmMemoryAddress memoryAddress) {
@@ -315,6 +321,16 @@ public class WasmBinaryFormatLinking {
                 return symbolIndex;
             }
         }
+
+        public WasmSymbolIndex tableNameToSymbolIndex(WasmTableName name) {
+            var symbolIndex = tableNameToSymbolIndex.get(name.value());
+            if (symbolIndex == null) {
+                // TODO: better error
+                throw new RuntimeException("could not find index for table: " + name);
+            } else {
+                return symbolIndex;
+            }
+        }
     }
 
     private static SymbolTable generateSymbolTable(WasmModule module) {
@@ -404,6 +420,7 @@ public class WasmBinaryFormatLinking {
             tagNameToSymbolIndex.put(tag.name(), symbolIndex);
         }
 
+        var tableNameToSymbolIndex = new HashMap<String, WasmSymbolIndex>();
         for (var table : module.indexedTables()) {
             var flags = switch (table) {
                 case WasmModule.IndexedTable.Definition definition ->
@@ -419,7 +436,10 @@ public class WasmBinaryFormatLinking {
                 table.name()
             );
 
+            var symbolIndex = new WasmSymbolIndex(symbolInfos.size());
             symbolInfos.add(tableSymbolInfo);
+
+            tableNameToSymbolIndex.put(table.name(), symbolIndex);
         }
 
         return new SymbolTable(
@@ -428,7 +448,8 @@ public class WasmBinaryFormatLinking {
             funcTypeToTypeIndex,
             funcNameToSymbolIndex,
             globalNameToSymbolIndex,
-            tagNameToSymbolIndex
+            tagNameToSymbolIndex,
+            tableNameToSymbolIndex
         );
     }
 
diff --git a/src/main/java/org/shedlang/compiler/backends/wasm/structure/binary/WasmBinaryWriter.java b/src/main/java/org/shedlang/compiler/backends/wasm/structure/binary/WasmBinaryWriter.java
index 4dc86a28..654d2a31 100644
--- a/src/main/java/org/shedlang/compiler/backends/wasm/structure/binary/WasmBinaryWriter.java
+++ b/src/main/java/org/shedlang/compiler/backends/wasm/structure/binary/WasmBinaryWriter.java
@@ -3,10 +3,7 @@ package org.shedlang.compiler.backends.wasm.structure.binary;
 import org.shedlang.compiler.backends.wasm.structure.BinaryWriter;
 import org.shedlang.compiler.backends.wasm.structure.ast.linking.WasmMemoryAddress;
 import org.shedlang.compiler.backends.wasm.structure.ast.linking.WasmRelocatableIndex;
-import org.shedlang.compiler.backends.wasm.structure.ast.modules.WasmFuncName;
-import org.shedlang.compiler.backends.wasm.structure.ast.modules.WasmGlobalName;
-import org.shedlang.compiler.backends.wasm.structure.ast.modules.WasmTableIndex;
-import org.shedlang.compiler.backends.wasm.structure.ast.modules.WasmTagName;
+import org.shedlang.compiler.backends.wasm.structure.ast.modules.*;
 import org.shedlang.compiler.backends.wasm.structure.ast.types.WasmFuncType;
 import org.shedlang.compiler.backends.wasm.structure.ast.types.WasmIndexType;
 
@@ -97,8 +94,13 @@ public class WasmBinaryWriter {
         );
     }
 
-    public void writeTableIndex(WasmTableIndex tableIndex) {
-        writeUnsignedInt32(tableIndex.value());
+    public void writeTableIndex(WasmTableName tableName) throws IOException {
+        var tableIndex = indexTable.tableIndex(tableName);
+        writeRelocatableIndex(
+            WasmRelocationType.TABLE_NUMBER_LEB,
+            OptionalInt.of(tableIndex.value()),
+            new WasmRelocatableIndex.TableIndex(tableName)
+        );
     }
 
     public void writeTableElementIndexConst(WasmFuncName funcName) throws IOException {
diff --git a/src/main/java/org/shedlang/compiler/backends/wasm/structure/binary/WasmIndexTable.java b/src/main/java/org/shedlang/compiler/backends/wasm/structure/binary/WasmIndexTable.java
index 61b56ffb..b01e7135 100644
--- a/src/main/java/org/shedlang/compiler/backends/wasm/structure/binary/WasmIndexTable.java
+++ b/src/main/java/org/shedlang/compiler/backends/wasm/structure/binary/WasmIndexTable.java
@@ -28,11 +28,17 @@ public class WasmIndexTable {
             tagNameToTagIndex.put(indexedTag.name(), indexedTag.tagIndex());
         }
 
+        var tableNameToTableIndex = new HashMap<String, WasmTableIndex>();
+        for (var indexedTable : module.indexedTables()) {
+            tableNameToTableIndex.put(indexedTable.name(), indexedTable.tableIndex());
+        }
+
         return new WasmIndexTable(
             funcTypeToTypeIndex,
             functionNameToFuncIndex,
             globalNameToGlobalIndex,
-            tagNameToTagIndex
+            tagNameToTagIndex,
+            tableNameToTableIndex
         );
     }
 
@@ -40,17 +46,20 @@ public class WasmIndexTable {
     private final Map<String, WasmFuncIndex> functionNameToFuncIndex;
     private final Map<String, WasmGlobalIndex> globalNameToGlobalIndex;
     private final Map<String, WasmTagIndex> tagNameToTagIndex;
+    private final Map<String, WasmTableIndex> tableNameToTableIndex;
 
     private WasmIndexTable(
         Map<WasmFuncType, WasmTypeIndex> funcTypeToTypeIndex,
         Map<String, WasmFuncIndex> functionNameToFuncIndex,
         Map<String, WasmGlobalIndex> globalNameToGlobalIndex,
-        Map<String, WasmTagIndex> tagNameToTagIndex
+        Map<String, WasmTagIndex> tagNameToTagIndex,
+        Map<String, WasmTableIndex> tableNameToTableIndex
     ) {
         this.funcTypeToTypeIndex = funcTypeToTypeIndex;
         this.functionNameToFuncIndex = functionNameToFuncIndex;
         this.globalNameToGlobalIndex = globalNameToGlobalIndex;
         this.tagNameToTagIndex = tagNameToTagIndex;
+        this.tableNameToTableIndex = tableNameToTableIndex;
     }
 
     public WasmTypeIndex typeIndex(WasmFuncType type) {
@@ -86,4 +95,14 @@ public class WasmIndexTable {
             return tagIndex;
         }
     }
+
+    public WasmTableIndex tableIndex(WasmTableName tableName) {
+        var tableIndex = tableNameToTableIndex.get(tableName.value());
+        if (tableIndex == null) {
+            // TODO: better error
+            throw new RuntimeException("missing table index for table: " + tableName.value());
+        } else {
+            return tableIndex;
+        }
+    }
 }