Force arrays to have a safety check

Improves BrainFuck

4 files changed, 35 insertions, 7 deletions

diff --git a/chapter15/src/main/java/com/seaofnodes/simple/Parser.java b/chapter15/src/main/java/com/seaofnodes/simple/Parser.java
index 64cde40f..012a010e 100644
--- a/chapter15/src/main/java/com/seaofnodes/simple/Parser.java
+++ b/chapter15/src/main/java/com/seaofnodes/simple/Parser.java
@@ -805,13 +805,22 @@ public class Parser {
                 Node val = parseExpression();
                 // Auto-truncate when storing to narrow fields
                 val = zsMask(val,f._type);
-                memAlias(f._alias, new StoreNode(name, f._alias, f._type, memAlias(f._alias), expr, off, val, false).peephole());
+                Node st = new StoreNode(name, f._alias, f._type, memAlias(f._alias), expr, off, val, false);
+                // Arrays include control, as a proxy for a safety range check.
+                // Structs dont need this; they only need a NPE check which is
+                // done via the type system.
+                if( base.isAry() )  st.setDef(0,ctrl());
+                memAlias(f._alias, st.peephole());
                 return val;        // "obj.a = expr" returns the expression while updating memory
             }
         }
 
-        Node load = new LoadNode(name, f._alias, f._type, memAlias(f._alias), expr, off).peephole();
-        return parsePostfix(load);
+        Node load = new LoadNode(name, f._alias, f._type, memAlias(f._alias), expr, off);
+        // Arrays include control, as a proxy for a safety range check
+        // Structs dont need this; they only need a NPE check which is
+        // done via the type system.
+        if( base.isAry() ) load.setDef(0,ctrl());
+        return parsePostfix(load.peephole());
     }
 
 
diff --git a/chapter15/src/main/java/com/seaofnodes/simple/node/NewNode.java b/chapter15/src/main/java/com/seaofnodes/simple/node/NewNode.java
index d7220bdc..f06564cd 100644
--- a/chapter15/src/main/java/com/seaofnodes/simple/node/NewNode.java
+++ b/chapter15/src/main/java/com/seaofnodes/simple/node/NewNode.java
@@ -38,10 +38,10 @@ public class NewNode extends Node implements MultiNode {
 
     @Override
     public TypeTuple compute() {
-        Type[] ts = new Type[nIns()];
+        Field[] fs = _ptr._obj._fields;
+        Type[] ts = new Type[fs.length+2];
         ts[0] = Type.CONTROL;
         ts[1] = _ptr;
-        Field[] fs = _ptr._obj._fields;
         for( int i=0; i<fs.length; i++ )
             ts[i+2] = TypeMem.make(fs[i]._alias,fs[i]._type.makeInit()).meet( in(i+2)._type );
         return TypeTuple.make(ts);
diff --git a/chapter15/src/test/java/com/seaofnodes/simple/BrainFuckTest.java b/chapter15/src/test/java/com/seaofnodes/simple/BrainFuckTest.java
index 894abbf6..03a22c55 100644
--- a/chapter15/src/test/java/com/seaofnodes/simple/BrainFuckTest.java
+++ b/chapter15/src/test/java/com/seaofnodes/simple/BrainFuckTest.java
@@ -26,7 +26,7 @@ public class BrainFuckTest {
                 encoded + """
 int pc = 0;
 int d = 0;
-u8[] data = new u8[10000];
+u8[] data = new u8[100];
 int i=0;
 while(i < data#) {
     data[i] = 0;
@@ -92,6 +92,6 @@ return result;
         for (byte b : "Hello Wo".getBytes(StandardCharsets.UTF_8)) {
             expected = (expected << 8) | b;
         }
-        assertEquals(expected, Evaluator.evaluate(stop, 0, 100000));
+        assertEquals(expected, Evaluator.evaluate(stop, 0, 10000));
     }
 }
diff --git a/chapter15/src/test/java/com/seaofnodes/simple/Chapter15Test.java b/chapter15/src/test/java/com/seaofnodes/simple/Chapter15Test.java
index 1aee2f0d..266d8a47 100644
--- a/chapter15/src/test/java/com/seaofnodes/simple/Chapter15Test.java
+++ b/chapter15/src/test/java/com/seaofnodes/simple/Chapter15Test.java
@@ -24,6 +24,25 @@ return 3.14;
     }
 
     @Test
+    public void testSafetyCheck() {
+        Parser parser = new Parser(
+"""
+u8[] old = new u8[0];
+u8[] output = new u8[1];
+int i = 0;
+while (i < old#) {
+    output[i] = old[i];
+    i = i + 1;
+}
+output[i] = 1;
+return output;
+""");
+        StopNode stop = parser.parse(false).iterate(true);
+        assertEquals("return u8[];", stop.toString());
+        assertEquals("Obj<u8[]> {\n  #=1\n  []=1\n}", Evaluator.evaluate(stop,  0).toString());
+    }
+
+    @Test
     public void testBasic1() {
         Parser parser = new Parser(
 """