Add WASM code gen for discard instruction

4 files changed, 15 insertions, 4 deletions

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 b572f77e..482d308e 100644
--- a/src/main/java/org/shedlang/compiler/backends/wasm/WasmCodeGen.java
+++ b/src/main/java/org/shedlang/compiler/backends/wasm/WasmCodeGen.java
@@ -1,5 +1,6 @@
 package org.shedlang.compiler.backends.wasm;
 
+import org.shedlang.compiler.backends.wasm.structure.ast.instructions.WasmDrop;
 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.*;
@@ -16,9 +17,9 @@ public class WasmCodeGen {
             case DefineFunctionInstruction defineFunctionInstruction -> {
                 throw new UnsupportedOperationException("TODO");
             }
-            case DiscardInstruction discardInstruction -> {
-                throw new UnsupportedOperationException("TODO");
-            }
+            case DiscardInstruction discard ->
+                context.addInstruction(new WasmDrop());
+
             case LocalLoadInstruction localLoadInstruction -> {
                 throw new UnsupportedOperationException("TODO");
             }
diff --git a/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/instructions/WasmDrop.java b/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/instructions/WasmDrop.java
new file mode 100644
index 00000000..fceeccdc
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/backends/wasm/structure/ast/instructions/WasmDrop.java
@@ -0,0 +1,4 @@
+package org.shedlang.compiler.backends.wasm.structure.ast.instructions;
+
+public record WasmDrop() implements WasmInstruction {
+}
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 b9cbd672..5cdd7a23 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, WasmReturn {
+public sealed interface WasmInstruction permits WasmDrop, WasmI32Const, WasmI64Const, WasmReturn {
 }
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 4bd9bb9a..988d8c9e 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
@@ -20,6 +20,12 @@ public class WasmBinaryFormatInstructions {
                 writer.writeByte(0x0f);
             }
 
+            // == Parametric Instructions ==
+
+            case WasmDrop ignored -> {
+                writer.writeByte(0x1a);
+            }
+
             // == Numeric Instructions ==
 
             case WasmI32Const i32Const -> {