From fccdbaa4487a4b3d10fa6e554ae9c73d11c12ebc Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Wed, 19 Jul 2023 20:49:13 +0100
Subject: Add alloc instruction to Patio IR

---
 src/main/java/org/shedlang/compiler/patio/PatioCodeGen.java    |  4 ++--
 .../shedlang/compiler/patio/PatioInstructionSerializer.java    |  6 +++++-
 .../org/shedlang/compiler/patio/instructions/PatioAlloc.java   | 10 ++++++++++
 .../shedlang/compiler/patio/instructions/PatioInstruction.java |  2 +-
 .../compiler/patio/PatioInstructionSerializerTests.java        |  9 +++++++++
 .../java/org/shedlang/compiler/patio/instructions/Patio.java   |  4 ++++
 6 files changed, 31 insertions(+), 4 deletions(-)
 create mode 100644 src/main/java/org/shedlang/compiler/patio/instructions/PatioAlloc.java

(limited to 'src')

diff --git a/src/main/java/org/shedlang/compiler/patio/PatioCodeGen.java b/src/main/java/org/shedlang/compiler/patio/PatioCodeGen.java
index 790bf8d7..dfe1e04b 100644
--- a/src/main/java/org/shedlang/compiler/patio/PatioCodeGen.java
+++ b/src/main/java/org/shedlang/compiler/patio/PatioCodeGen.java
@@ -17,8 +17,8 @@ public class PatioCodeGen {
             case DiscardInstruction discard ->
                 P.vector(new PatioDiscard(discard.source()));
 
-            case ReturnInstruction discard ->
-                P.vector(new PatioReturn(discard.source()));
+            case ReturnInstruction return_ ->
+                P.vector(new PatioReturn(return_.source()));
 
             default ->
                 throw new IllegalStateException("Unexpected value: " + stackIrInstruction);
diff --git a/src/main/java/org/shedlang/compiler/patio/PatioInstructionSerializer.java b/src/main/java/org/shedlang/compiler/patio/PatioInstructionSerializer.java
index 523eabc7..382c4125 100644
--- a/src/main/java/org/shedlang/compiler/patio/PatioInstructionSerializer.java
+++ b/src/main/java/org/shedlang/compiler/patio/PatioInstructionSerializer.java
@@ -1,5 +1,6 @@
 package org.shedlang.compiler.patio;
 
+import org.shedlang.compiler.patio.instructions.PatioAlloc;
 import org.shedlang.compiler.patio.instructions.PatioDiscard;
 import org.shedlang.compiler.patio.instructions.PatioInstruction;
 import org.shedlang.compiler.patio.instructions.PatioReturn;
@@ -33,10 +34,13 @@ public class PatioInstructionSerializer {
 
     private static Tree instructionToTree(PatioInstruction instruction) {
         return switch (instruction) {
+            case PatioAlloc alloc ->
+                treeList(treeIdentifier("alloc"), treeInt(alloc.bytes()));
+
             case PatioDiscard discard ->
                 treeList(treeIdentifier("discard"));
 
-            case PatioReturn patioReturn ->
+            case PatioReturn return_ ->
                 treeList(treeIdentifier("return"));
         };
     }
diff --git a/src/main/java/org/shedlang/compiler/patio/instructions/PatioAlloc.java b/src/main/java/org/shedlang/compiler/patio/instructions/PatioAlloc.java
new file mode 100644
index 00000000..c5ea9594
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/patio/instructions/PatioAlloc.java
@@ -0,0 +1,10 @@
+package org.shedlang.compiler.patio.instructions;
+
+import org.shedlang.compiler.sources.Source;
+
+/**
+ * Allocate the given number of bytes, and push the pointer to the allocated
+ * memory onto the stack.
+ */
+public record PatioAlloc(int bytes, Source source) implements PatioInstruction {
+}
diff --git a/src/main/java/org/shedlang/compiler/patio/instructions/PatioInstruction.java b/src/main/java/org/shedlang/compiler/patio/instructions/PatioInstruction.java
index 22305e84..6928d324 100644
--- a/src/main/java/org/shedlang/compiler/patio/instructions/PatioInstruction.java
+++ b/src/main/java/org/shedlang/compiler/patio/instructions/PatioInstruction.java
@@ -2,6 +2,6 @@ package org.shedlang.compiler.patio.instructions;
 
 import org.shedlang.compiler.sources.Source;
 
-public sealed interface PatioInstruction permits PatioDiscard, PatioReturn {
+public sealed interface PatioInstruction permits PatioAlloc, PatioDiscard, PatioReturn {
     Source source();
 }
diff --git a/src/test/java/org/shedlang/compiler/patio/PatioInstructionSerializerTests.java b/src/test/java/org/shedlang/compiler/patio/PatioInstructionSerializerTests.java
index 1ea128c8..add91040 100644
--- a/src/test/java/org/shedlang/compiler/patio/PatioInstructionSerializerTests.java
+++ b/src/test/java/org/shedlang/compiler/patio/PatioInstructionSerializerTests.java
@@ -8,6 +8,15 @@ import static org.zwobble.precisely.AssertThat.assertThat;
 import static org.zwobble.precisely.Matchers.equalTo;
 
 public class PatioInstructionSerializerTests {
+    @Test
+    public void canSerializeAlloc() {
+        var instruction = Patio.alloc(42);
+
+        var string = serialize(instruction);
+
+        assertThat(string, equalTo("(alloc 42)"));
+    }
+
     @Test
     public void canSerializeDiscard() {
         var instruction = Patio.discard();
diff --git a/src/test/java/org/shedlang/compiler/patio/instructions/Patio.java b/src/test/java/org/shedlang/compiler/patio/instructions/Patio.java
index 871f45f1..ad7748bc 100644
--- a/src/test/java/org/shedlang/compiler/patio/instructions/Patio.java
+++ b/src/test/java/org/shedlang/compiler/patio/instructions/Patio.java
@@ -5,6 +5,10 @@ import org.shedlang.compiler.sources.Sources;
 public class Patio {
     private Patio() {}
 
+    public static PatioInstruction alloc(int bytes) {
+        return new PatioAlloc(bytes, Sources.NULL);
+    }
+
     public static PatioInstruction discard() {
         return new PatioDiscard(Sources.NULL);
     }
-- 
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