From 6aa1d4c0dd57790b65f90b2c69b484ad64ce74bc Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Sun, 25 Jun 2023 15:55:14 +0100
Subject: Add WASM code gen for return instruction

---
 .../java/org/shedlang/compiler/backends/wasm/WasmCodeGen.java |  6 +++---
 .../wasm/structure/ast/instructions/WasmInstruction.java      |  2 +-
 .../backends/wasm/structure/ast/instructions/WasmReturn.java  |  4 ++++
 .../wasm/structure/binary/WasmBinaryFormatInstructions.java   | 11 +++++++----
 4 files changed, 15 insertions(+), 8 deletions(-)
 create mode 100644 src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/instructions/WasmReturn.java

(limited to 'src/main/java')

diff --git a/src/main/java/org/shedlang/compiler/backends/wasm/WasmCodeGen.java b/src/main/java/org/shedlang/compiler/backends/wasm/WasmCodeGen.java
index e71d1f15..b572f77e 100644
--- a/src/main/java/org/shedlang/compiler/backends/wasm/WasmCodeGen.java
+++ b/src/main/java/org/shedlang/compiler/backends/wasm/WasmCodeGen.java
@@ -1,6 +1,7 @@
 package org.shedlang.compiler.backends.wasm;
 
 import org.shedlang.compiler.backends.wasm.structure.ast.instructions.WasmI32Const;
+import org.shedlang.compiler.backends.wasm.structure.ast.instructions.WasmReturn;
 import org.shedlang.compiler.stackir.instructions.*;
 
 public class WasmCodeGen {
@@ -39,9 +40,8 @@ public class WasmCodeGen {
             case PushUnitInstruction pushUnit ->
                 context.addInstruction(new WasmI32Const(0));
 
-            case ReturnInstruction returnInstruction -> {
-                throw new UnsupportedOperationException("TODO");
-            }
+            case ReturnInstruction returnInstruction ->
+                context.addInstruction(new WasmReturn());
         };
     }
 }
diff --git a/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/instructions/WasmInstruction.java b/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/instructions/WasmInstruction.java
index 4f33a003..b9cbd672 100644
--- a/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/instructions/WasmInstruction.java
+++ b/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/instructions/WasmInstruction.java
@@ -1,4 +1,4 @@
 package org.shedlang.compiler.backends.wasm.structure.ast.instructions;
 
-public sealed interface WasmInstruction permits WasmI32Const, WasmI64Const {
+public sealed interface WasmInstruction permits WasmI32Const, WasmI64Const, WasmReturn {
 }
diff --git a/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/instructions/WasmReturn.java b/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/instructions/WasmReturn.java
new file mode 100644
index 00000000..6566468e
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/instructions/WasmReturn.java
@@ -0,0 +1,4 @@
+package org.shedlang.compiler.backends.wasm.structure.ast.instructions;
+
+public record WasmReturn() implements WasmInstruction {
+}
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 3ed6b618..4bd9bb9a 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
@@ -1,10 +1,7 @@
 package org.shedlang.compiler.backends.wasm.structure.binary;
 
 import org.shedlang.compiler.backends.wasm.structure.BinaryWriter;
-import org.shedlang.compiler.backends.wasm.structure.ast.instructions.WasmExpression;
-import org.shedlang.compiler.backends.wasm.structure.ast.instructions.WasmI32Const;
-import org.shedlang.compiler.backends.wasm.structure.ast.instructions.WasmI64Const;
-import org.shedlang.compiler.backends.wasm.structure.ast.instructions.WasmInstruction;
+import org.shedlang.compiler.backends.wasm.structure.ast.instructions.*;
 
 import java.io.IOException;
 
@@ -17,6 +14,12 @@ public class WasmBinaryFormatInstructions {
     private static void writeInstruction(WasmInstruction instruction, BinaryWriter writer) {
         switch (instruction) {
 
+            // == Control Instructions ==
+
+            case WasmReturn ignored -> {
+                writer.writeByte(0x0f);
+            }
+
             // == Numeric Instructions ==
 
             case WasmI32Const i32Const -> {
-- 
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