Add unreachable instruction to Patio

5 files changed, 21 insertions, 1 deletions

diff --git a/src/main/java/org/shedlang/compiler/backends/llvm/LlvmPatioCodeGen.java b/src/main/java/org/shedlang/compiler/backends/llvm/LlvmPatioCodeGen.java
index 167c85be..c4a23ac6 100644
--- a/src/main/java/org/shedlang/compiler/backends/llvm/LlvmPatioCodeGen.java
+++ b/src/main/java/org/shedlang/compiler/backends/llvm/LlvmPatioCodeGen.java
@@ -506,6 +506,9 @@ public class LlvmPatioCodeGen {
                     patioOperandToLlvmOperand(patioReturn.value(), context)
                 ));
 
+            case PatioUnreachable patioUnreachable ->
+                throw new UnsupportedOperationException();
+
             case PatioVarLoad patioVarLoad -> {
                 var targetResult = context.addPatioLocalToLlvmLocal(patioVarLoad.target());
                 var target = targetResult.value;
diff --git a/src/main/java/org/shedlang/compiler/backends/wasm/WasmPatioCodeGen.java b/src/main/java/org/shedlang/compiler/backends/wasm/WasmPatioCodeGen.java
index dadfa918..d315bfdd 100644
--- a/src/main/java/org/shedlang/compiler/backends/wasm/WasmPatioCodeGen.java
+++ b/src/main/java/org/shedlang/compiler/backends/wasm/WasmPatioCodeGen.java
@@ -306,6 +306,10 @@ public class WasmPatioCodeGen {
                 yield context;
             }
 
+            case PatioUnreachable patioUnreachable -> {
+                throw new UnsupportedOperationException("TODO");
+            }
+
             case PatioVarLoad patioVarLoad -> {
                 yield generateOperandToPatioLocal(
                     patioVarLoad.target(),
diff --git a/src/main/java/org/shedlang/compiler/patio/ast/PatioSerializer.java b/src/main/java/org/shedlang/compiler/patio/ast/PatioSerializer.java
index c8b51f0a..c581e180 100644
--- a/src/main/java/org/shedlang/compiler/patio/ast/PatioSerializer.java
+++ b/src/main/java/org/shedlang/compiler/patio/ast/PatioSerializer.java
@@ -293,6 +293,9 @@ public class PatioSerializer {
                     operandToTree(return_.value())
                 );
 
+            case PatioUnreachable unreachable ->
+                treeList(treeIdentifier("unreachable"));
+
             case PatioVarLoad varLoad ->
                 treeList(
                     treeIdentifier("var-load"),
diff --git a/src/main/java/org/shedlang/compiler/patio/ast/instructions/PatioInstruction.java b/src/main/java/org/shedlang/compiler/patio/ast/instructions/PatioInstruction.java
index f68f752e..8b11d25b 100644
--- a/src/main/java/org/shedlang/compiler/patio/ast/instructions/PatioInstruction.java
+++ b/src/main/java/org/shedlang/compiler/patio/ast/instructions/PatioInstruction.java
@@ -2,6 +2,6 @@ package org.shedlang.compiler.patio.ast.instructions;
 
 import org.shedlang.compiler.sources.Source;
 
-public sealed interface PatioInstruction permits PatioAllocHeap, PatioBoolToInt, PatioCall, PatioCallPointer, PatioDataPtrToInt, PatioIf, PatioIntAdd, PatioIntEquals, PatioIntNotEqual, PatioIntSub, PatioIntToBool, PatioIntToDataPtr, PatioLocalStore, PatioLoop, PatioLoopBreak, PatioLoopContinue, PatioMemoryLoad, PatioMemoryStore, PatioReturn, PatioVarLoad, PatioVarStore {
+public sealed interface PatioInstruction permits PatioAllocHeap, PatioBoolToInt, PatioCall, PatioCallPointer, PatioDataPtrToInt, PatioIf, PatioIntAdd, PatioIntEquals, PatioIntNotEqual, PatioIntSub, PatioIntToBool, PatioIntToDataPtr, PatioLocalStore, PatioLoop, PatioLoopBreak, PatioLoopContinue, PatioMemoryLoad, PatioMemoryStore, PatioReturn, PatioUnreachable, PatioVarLoad, PatioVarStore {
     Source source();
 }
diff --git a/src/main/java/org/shedlang/compiler/patio/ast/instructions/PatioUnreachable.java b/src/main/java/org/shedlang/compiler/patio/ast/instructions/PatioUnreachable.java
new file mode 100644
index 00000000..55821afe
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/patio/ast/instructions/PatioUnreachable.java
@@ -0,0 +1,10 @@
+package org.shedlang.compiler.patio.ast.instructions;
+
+import org.shedlang.compiler.sources.Source;
+
+/**
+ * Unreachable instructions have undefined behaviour, and are used to indicate
+ * that an instruction sequence is unreachable.
+ */
+public record PatioUnreachable(Source source) implements PatioInstruction {
+}