Use runtime type tag as struct tag

5 files changed, 50 insertions, 24 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 6c5f96da..63ab8d3a 100644
--- a/src/main/java/org/shedlang/compiler/backends/wasm/PatioToWasm.java
+++ b/src/main/java/org/shedlang/compiler/backends/wasm/PatioToWasm.java
@@ -380,11 +380,11 @@ public class PatioToWasm {
 
                 for (var patioSwitchCase : patioSwitch.cases()) {
                     context = generateOperand(patioSwitch.value(), context);
-                    context = context.addInstruction(wasmIntConst(
-                        target.patioIntType(),
+                    // TODO: should probably allow any int type in switches
+                    context = context.addInstruction(new WasmI32Const(
                         patioSwitchCase.value()
                     ));
-                    context = context.addInstruction(wasmIntEq(target.patioIntType()));
+                    context = context.addInstruction(new WasmI32Eq());
                     context = context.enterIfInstruction(wasmBlockType);
                     context = generateBlockBody(patioSwitchCase.body(), context);
                     context = context.enterElse();
diff --git a/src/main/java/org/shedlang/compiler/shidtopatio/ShidToPatioContext.java b/src/main/java/org/shedlang/compiler/shidtopatio/ShidToPatioContext.java
index 04644052..cab33a07 100644
--- a/src/main/java/org/shedlang/compiler/shidtopatio/ShidToPatioContext.java
+++ b/src/main/java/org/shedlang/compiler/shidtopatio/ShidToPatioContext.java
@@ -38,13 +38,12 @@ public record ShidToPatioContext(
 
         @CheckReturnValue
         public static GlobalContext forTypeInfos(TypeInfos typeInfos) {
-            var structTags = generateStructTags(typeInfos);
             var effectTags = generateEffectTags(typeInfos);
             var runtimeTypeTags = P.<RuntimeType, Integer>orderedPMap();
 
             var context = new GlobalContext(
                 typeInfos,
-                structTags,
+                P.map(),
                 effectTags,
                 runtimeTypeTags
             );
@@ -53,18 +52,33 @@ public record ShidToPatioContext(
             // runtime (for instance, when allocating ints and strings).
             context = context.addRuntimeTypeTag(ScalarRuntimeType.INSTANCE);
 
+            context = generateStructTags(context);
+
             return context;
         }
 
         @CheckReturnValue
-        private static PMap<SimpleStructType, Integer> generateStructTags(TypeInfos typeInfos) {
-            var tags = P.<SimpleStructType, Integer>map();
-            var nextTag = 0;
-            for (var structType : typeInfos.structTypes()) {
-                tags = tags.plus(structType, nextTag);
-                nextTag++;
+        private static GlobalContext generateStructTags(GlobalContext context) {
+            var structTags = P.<SimpleStructType, Integer>map();
+
+            for (var structType : context.typeInfos.structTypes()) {
+                // TODO: get struct types with infos to avoid potential throw.
+                var structTypeInfo = context.typeInfos.structTypeInfo(structType).orElseThrow();
+                var structRuntimeType = ShidToPatioStructs.structRuntimeType(structType, structTypeInfo);
+
+                var runtimeTypeTagResult = context.runtimeTypeTag(structRuntimeType);
+                var runtimeTypeTag = runtimeTypeTagResult.value();
+                context = runtimeTypeTagResult.context();
+
+                structTags = structTags.plus(structType, runtimeTypeTag);
             }
-            return tags;
+
+            return new GlobalContext(
+                context.typeInfos,
+                structTags,
+                context.effectTags,
+                context.runtimeTypeTags
+            );
         }
 
         @CheckReturnValue
diff --git a/src/main/java/org/shedlang/compiler/shidtopatio/ShidToPatioGc.java b/src/main/java/org/shedlang/compiler/shidtopatio/ShidToPatioGc.java
index dff665f9..dd6e161b 100644
--- a/src/main/java/org/shedlang/compiler/shidtopatio/ShidToPatioGc.java
+++ b/src/main/java/org/shedlang/compiler/shidtopatio/ShidToPatioGc.java
@@ -20,17 +20,23 @@ public class ShidToPatioGc {
     private ShidToPatioGc() {
     }
 
+    public static final PatioType RUNTIME_TYPE_TAG_TYPE = PatioTypes.INT32;
+
     public static PatioDataLayout gcObjectDataLayout(PatioDataLayout valueLayout) {
         return PatioDataLayouts.struct(List.of(
             PatioDataLayouts.struct(List.of(
                 PatioDataLayouts.DATA_PTR, // next
                 PatioDataLayouts.INT32, // mark
-                PatioDataLayouts.INT32 // runtime type tag
+                PatioDataLayouts.fromType(RUNTIME_TYPE_TAG_TYPE) // runtime type tag
             )),
             valueLayout
         ));
     }
 
+    public static List<Integer> runtimeTypeTagOffset() {
+        return List.of(0, 2);
+    }
+
     public static List<Integer> gcObjectOffset(List<Integer> valueOffset) {
         return Lists.concat(List.of(1), valueOffset);
     }
diff --git a/src/main/java/org/shedlang/compiler/shidtopatio/ShidToPatioStructs.java b/src/main/java/org/shedlang/compiler/shidtopatio/ShidToPatioStructs.java
index 8cce8d9a..edf1707e 100644
--- a/src/main/java/org/shedlang/compiler/shidtopatio/ShidToPatioStructs.java
+++ b/src/main/java/org/shedlang/compiler/shidtopatio/ShidToPatioStructs.java
@@ -12,6 +12,7 @@ import org.shedlang.compiler.sources.Source;
 import org.shedlang.compiler.shid.instructions.ShidDefineFunction;
 import org.shedlang.compiler.shid.instructions.ShidDefineStruct;
 import org.shedlang.compiler.types.SimpleStructType;
+import org.shedlang.compiler.types.StructTypeInfo;
 import org.shedlang.compiler.util.Lists;
 
 import java.util.List;
@@ -21,36 +22,40 @@ public class ShidToPatioStructs {
     }
 
     private static PatioDataLayout unknownStructDataLayout() {
-        return ShidToPatioGc.gcObjectDataLayout(PatioDataLayouts.struct(List.of(
-            PatioDataLayouts.INT
-        )));
+        return ShidToPatioGc.gcObjectDataLayout(PatioDataLayouts.struct(List.of()));
     }
 
     private static final List<Integer> TAG_OFFSET
-        = ShidToPatioGc.gcObjectOffset(List.of(0));
+        = ShidToPatioGc.runtimeTypeTagOffset();
 
     private static StructRuntimeType structRuntimeType(
         SimpleStructType type,
         ShidToPatioContext context
     ) {
         var structTypeInfo = context.structTypeInfo(type);
+        return structRuntimeType(type, structTypeInfo);
+    }
+
+    public static StructRuntimeType structRuntimeType(
+        SimpleStructType type,
+        StructTypeInfo structTypeInfo
+    ) {
         return new StructRuntimeType(type, structTypeInfo.fieldCount());
     }
 
-    private record StructRuntimeType(SimpleStructType type, int fieldCount) implements RuntimeType {
+    public record StructRuntimeType(SimpleStructType type, int fieldCount) implements RuntimeType {
         @Override
         public PatioDataLayout layout() {
-            return ShidToPatioGc.gcObjectDataLayout(PatioDataLayouts.struct(List.of(
-                PatioDataLayouts.INT,
+            return ShidToPatioGc.gcObjectDataLayout(
                 PatioDataLayouts.struct(Lists.repeat(
                     PatioDataLayouts.INT,
                     fieldCount
                 ))
-            )));
+            );
         }
 
         private static final List<Integer> GC_CHILDREN_OFFSET =
-            ShidToPatioGc.gcObjectOffset(List.of(1));
+            ShidToPatioGc.gcObjectOffset(List.of());
 
         @Override
         public List<Integer> gcChildrenOffset() {
@@ -67,7 +72,7 @@ public class ShidToPatioStructs {
         }
 
         public List<Integer> fieldOffset(int fieldIndex) {
-            return ShidToPatioGc.gcObjectOffset(List.of(1, fieldIndex));
+            return ShidToPatioGc.gcObjectOffset(List.of(fieldIndex));
         }
     }
 
diff --git a/src/main/java/org/shedlang/compiler/shidtopatio/ShidToPatioTypes.java b/src/main/java/org/shedlang/compiler/shidtopatio/ShidToPatioTypes.java
index 1288d430..74f9bd09 100644
--- a/src/main/java/org/shedlang/compiler/shidtopatio/ShidToPatioTypes.java
+++ b/src/main/java/org/shedlang/compiler/shidtopatio/ShidToPatioTypes.java
@@ -6,6 +6,7 @@ import org.shedlang.compiler.patio.types.PatioTypes;
 public class ShidToPatioTypes {
     private ShidToPatioTypes() {}
 
-    public static final PatioType TAG_TYPE = PatioTypes.INT;
+    // TODO: remove duplication with ShidToPatioStructs
+    public static final PatioType TAG_TYPE = PatioTypes.INT32;
     public static final PatioType VALUE_TYPE = PatioTypes.INT;
 }