Fix ++x in methods

Fix ideaj setups

2 files changed, 82 insertions, 23 deletions

diff --git a/chapter24a/src/main/java/com/seaofnodes/simple/Parser.java b/chapter24a/src/main/java/com/seaofnodes/simple/Parser.java
index 81c7be32..7a67c096 100644
--- a/chapter24a/src/main/java/com/seaofnodes/simple/Parser.java
+++ b/chapter24a/src/main/java/com/seaofnodes/simple/Parser.java
@@ -1246,19 +1246,17 @@ public class Parser {
         // Pre-dec/pre-inc
         int old = pos();
         if( match("--") || match("++") ) {
-            int delta = _lexer.peek(-1)=='+' ? 1 : -1; // Pre vs post
+            int delta = _lexer.peek(-1)=='+' ? 1 : -1; // Inc vs Dec
+            int start = pos();
             String name = _lexer.matchId();
-            if( name!=null ) {
-                Var n = _scope.lookup(name);
-                if( n != null && !(n.type() instanceof TypeMemPtr) ) {
-                    if( n._final )
-                        throw error("Cannot reassign final '"+n._name+"'");
-                    Node expr = n.type() instanceof TypeFloat
-                        ?        peep(new AddFNode(_scope.in(n),con(TypeFloat.constant(delta))))
-                        : zsMask(peep(new  AddNode(_scope.in(n),con(delta))),n.type());
-                    _scope.update(n,expr);
-                    return expr;
-                }
+            Var var = name==null ? null : _scope.lookup(name);
+            if( var!=null && !(var.type() instanceof TypeMemPtr) ) {
+                if( var._final )
+                    throw error("Cannot reassign final '"+var._name+"'");
+                // Resolve fields just as a read or postfix update does. Updating
+                // their declaration's local slot would silently lose the Store.
+                pos(start);
+                return parsePrimary(delta);
             }
             // Reset, try again
             pos(old);
@@ -1279,7 +1277,10 @@ public class Parser {
      * </pre>
      * @return a primary {@link Node}, never {@code null}
      */
-    private Node parsePrimary() {
+    private Node parsePrimary() { return parsePrimary(0); }
+
+    // pre is +/-1 for a prefix update of a known name, zero otherwise.
+    private Node parsePrimary(int pre) {
         if( _lexer.isNumber(_lexer.peek()) ) return parseLiteral();
         if( _lexer.peek('"') ) return newString(parseString());
         if( matchx("true" ) ) return con(1);
@@ -1326,7 +1327,7 @@ public class Parser {
         // Else safety check for accessing fields out of function scope.
         if( instance(var) ) {
             Node self = _scope.in(_scope.lookup("self")); // Insert self reference
-            return parsePostfixName(self,id);
+            return parsePostfixName(self,id,pre);
         }
 
         // Load local value
@@ -1337,7 +1338,7 @@ public class Parser {
             else throw error("Cannot read uninitialized field '"+id+"'");
 
         // Check for assign-update, x += e0;
-        char ch = _lexer.matchOperAssign();
+        char ch = pre==0 ? _lexer.matchOperAssign() : (char)pre;
         if( ch==0  )            // Normal primary, check for postfix updates
             return parsePostfix(rvalue);
         // Assign-update direct into Scope
@@ -1345,7 +1346,8 @@ public class Parser {
             throw error("Cannot reassign final '"+var._name+"'");
         Node op = opAssign(ch,rvalue, var.type() );
         _scope.update(var,op);
-        return postfix(ch) ? rvalue.unkeep() : op;
+        if( postfix(ch) ) rvalue.unkeep();
+        return pre==0 && postfix(ch) ? rvalue : op;
     }
 
     // true if instance variable lookup (var is in any number of nested blocks,
@@ -1574,7 +1576,9 @@ public class Parser {
      *     expr ('[' expr ']')* [ [op]= expr ] // Array reference
      * </pre>
      */
-    private Node parsePostfixName(Node expr, String name) {
+    private Node parsePostfixName(Node expr, String name) { return parsePostfixName(expr,name,0); }
+
+    private Node parsePostfixName(Node expr, String name, int pre) {
 
         if( expr._type==Type.NIL )
             throw error("Accessing unknown field '" + name + "' from 'null'");
@@ -1609,7 +1613,7 @@ public class Parser {
             : off(base,name)).keep();
 
         // Disambiguate "obj.fld==x" boolean test from "obj.fld=x" field assignment
-        if( matchOpx('=','=') ) {
+        if( pre==0 && matchOpx('=','=') ) {
             Node val = parseAsgn().keep();
             Node lift = liftExpr( val, tf, false );
 
@@ -1628,14 +1632,16 @@ public class Parser {
         load = peep(load);
 
         // Check for assign-update, "ptr.fld += expr" or "ary[idx]++"
-        char ch = _lexer.matchOperAssign();
+        char ch = pre==0 ? _lexer.matchOperAssign() : (char)pre;
         if( ch!=0 ) {
             Node op = opAssign(ch,load,tf);
+            // A narrow Store may drop its conversion; prefix still returns it.
+            if( pre!=0 ) op.keep();
             store(name,f._alias,tf,expr.unkeep(),off.unkeep(),op,false,base.isAry() ? ctrl() : null);
-            load = postfix(ch) ? load.unkeep() : op;
-            // And use the original loaded value as the result
-            return load;
-            //throw Utils.TODO(); // NO POSTFIX AFTER STORE, JUST RETURN
+            if( pre!=0 ) op.unkeep();
+            if( postfix(ch) ) load.unkeep();
+            // Prefix returns the new value; postfix returns the old load.
+            return pre==0 && postfix(ch) ? load : op;
         } else {
             off.unkill();
             // Method call: Loaded a function from a named field, AND the base
diff --git a/chapter24a/src/test/java/com/seaofnodes/simple/PrefixUpdateTest.java b/chapter24a/src/test/java/com/seaofnodes/simple/PrefixUpdateTest.java
new file mode 100644
index 00000000..56d553b3
--- /dev/null
+++ b/chapter24a/src/test/java/com/seaofnodes/simple/PrefixUpdateTest.java
@@ -0,0 +1,53 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.codegen.CodeGen;
+import com.seaofnodes.simple.type.TypeInteger;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class PrefixUpdateTest {
+    @Test public void testMethodFieldWrites() {
+        String[] fields = {"int x=0", "int x=3", "u8 x=0", "f32 x=0"};
+        String[] updates = {"++x", "--x", "++x", "++x"};
+        String[] results = {"221", "112", "221", "221.0"};
+        for(int i=0;i<fields.length;i++)
+            for(int seed:new int[]{2,13,123}) {
+                String src="struct C { "+fields[i]+"; val change_noInline={ -> "+updates[i]+"; }; }; "
+                    +"var c=new C; val a=c.change_noInline(); val b=c.change_noInline(); return a+10*b+100*c.x;";
+                CodeGen code=new CodeGen(src,TypeInteger.BOT,seed,true).driver(CodeGen.Phase.TypeCheck);
+                assertEquals(fields[i],results[i],Eval2.eval(code,0));
+            }
+    }
+
+    @Test public void testLocalAndFinalUpdates() {
+        CodeGen code=new CodeGen("int x=arg; return ++x*100 + --x*10 + x;").driver(CodeGen.Phase.TypeCheck);
+        assertEquals("433",Eval2.eval(code,3));
+        code=new CodeGen("struct C { int x=7; val f={int x -> ++x;}; }; var c=new C; return c.f(3)+10*c.x;")
+            .driver(CodeGen.Phase.TypeCheck);
+        assertEquals("74",Eval2.eval(code,0));
+        for(String src:new String[]{"val x=1; return ++x;",
+                                   "struct C { val x=1; val f={ -> ++x; }; }; var c=new C; return c.f();"}) {
+            try {
+                new CodeGen(src).driver(CodeGen.Phase.TypeCheck);
+                fail("final update");
+            } catch(RuntimeException e) {
+                assertTrue(e.getMessage(),e.getMessage().contains("final"));
+            }
+        }
+    }
+
+    @Test public void testNativeByteOverflow() throws java.io.IOException {
+        String src="val prefixUpdate={int arg -> "
+            +"struct C { u8 x=255; val inc_noInline={ -> ++x; }; }; "
+            +"var c=new C; val a=c.inc_noInline(); val b=c.inc_noInline(); return a+10*b+100*c.x; };";
+        var dir=java.nio.file.Path.of("build/objs");
+        java.nio.file.Files.createDirectories(dir);
+        var driver=dir.resolve("prefixUpdate.c");
+        java.nio.file.Files.writeString(driver,"""
+            __attribute__((CALL_CONV)) extern long long prefixUpdate(long long);
+            int main(void) { return prefixUpdate(0)!=110; }
+            """);
+        String abi=TestC.OS.startsWith("Windows") ? "ms_abi" : "sysv_abi";
+        TestC.run(src,TestC.CALL_CONVENTION,null,abi,driver.toString(),"build/objs/prefixUpdate","S","",-1);
+    }
+}