Chapter 25: Modules, Separate Compilation, and SSA Constructionlinear

Co-authored-by: Hsiang-Ying Fu <66062782+fuhsnn@users.noreply.github.com>
Co-authored-by: fuhsnn <66062782+fuhsnn@users.noreply.github.com>
Co-authored-by: Symious <14933944+symious@users.noreply.github.com>
Co-authored-by: Jun Kawasaki <jun784@gmail.com>
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

1 files changed, 48 insertions, 0 deletions

diff --git a/src/main/java/com/seaofnodes/simple/node/FldOffNode.java b/src/main/java/com/seaofnodes/simple/node/FldOffNode.java
new file mode 100644
index 00000000..ef894929
--- /dev/null
+++ b/src/main/java/com/seaofnodes/simple/node/FldOffNode.java
@@ -0,0 +1,48 @@
+package com.seaofnodes.simple.node;
+
+import com.seaofnodes.print.ExprPrinter;
+
+import com.seaofnodes.simple.Parser;
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.type.*;
+import com.seaofnodes.simple.util.SB;
+import com.seaofnodes.simple.util.Utils;
+import java.util.HashMap;
+
+/**
+ * A field offset.  This becomes a constant *after* other optimizations which
+ * determine field sizes - some fields might be dead, or hold only zeros or
+ * small values.
+ */
+
+public class FldOffNode extends TypeNode {
+    public final String _fname; // Field name
+    public final Parser.Lexer _loc;   //
+    public FldOffNode( Node base, String fname, Parser.Lexer loc ) { super(TypeInteger.BOT,base); _fname = fname; _loc=loc; }
+    @Override public Tag serialTag() { throw Utils.TODO("should not reach here"); }
+
+    @Override public String label() {
+        return _fname == " len" ? "sizeof()" : "#"+_fname;
+    }
+
+    @Override protected ExprPrinter<Node> _print1(ExprPrinter<Node> p) {
+        return p.p(label());
+    }
+
+    @Override public Type compute() {
+        return Type.BOTTOM;
+    }
+
+    @Override public Node idealize() {
+        // When base() gets typed, this xforms into a ConFldOffNode
+        if( in(0)._type instanceof TypeMemPtr tmp )
+            return new ConFldOffNode(tmp._obj,_fname);
+        return null;
+    }
+
+    @Override public boolean eq(Node n) {
+        FldOffNode off = (FldOffNode)n; // Invariant
+        return _fname.equals(off._fname) && super.eq(n);
+    }
+    @Override int hash() { return super.hash() * _fname.hashCode(); }
+}