Fix ++x in methods

Fix ideaj setups

3 files changed, 126 insertions, 34 deletions

diff --git a/chapter27/chapter27.iml b/chapter27/chapter27.iml
new file mode 100644
index 00000000..40cc410d
--- /dev/null
+++ b/chapter27/chapter27.iml
@@ -0,0 +1,31 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="false">
+    <output url="file://$MODULE_DIR$/../build/idea/production/chapter27" />
+    <output-test url="file://$MODULE_DIR$/../build/idea/test/chapter27" />
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src/main/java" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/src/test/java" isTestSource="true" />
+      <excludeFolder url="file://$MODULE_DIR$/build" />
+      <excludeFolder url="file://$MODULE_DIR$/target" />
+      <excludeFolder url="file://$MODULE_DIR$/lib" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="module" module-name="graph" />
+    <orderEntry type="module" module-name="print" />
+    <orderEntry type="module" module-name="isa" />
+    <orderEntry type="module" module-name="isa-eval" scope="TEST" />
+    <orderEntry type="module-library" scope="TEST">
+      <library name="JUnit4">
+        <CLASSES>
+          <root url="jar://$MODULE_DIR$/lib/junit-4.12.jar!/" />
+          <root url="jar://$MODULE_DIR$/lib/hamcrest-core-1.3.jar!/" />
+        </CLASSES>
+        <JAVADOC />
+        <SOURCES />
+      </library>
+    </orderEntry>
+  </component>
+</module>
diff --git a/chapter27/src/main/java/com/seaofnodes/simple/Parser.java b/chapter27/src/main/java/com/seaofnodes/simple/Parser.java
index 145feb15..93ad8f4e 100644
--- a/chapter27/src/main/java/com/seaofnodes/simple/Parser.java
+++ b/chapter27/src/main/java/com/seaofnodes/simple/Parser.java
@@ -1475,18 +1475,17 @@ 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 && !_scope.canInit(n) )
-                        throw error("Cannot reassign final '"+n._name+"'");
-                    checkSharedField(n);
-                    Node expr = liftExpr(peep(new AddNode(_scope.in(n),con(delta))),n.type(),true);
-                    _scope.update(n,expr);
-                    return expr;
-                }
+            Var var = name==null ? null : _scope.lookup(name);
+            if( var!=null && !(var.type() instanceof TypeMemPtr) ) {
+                if( var._final && !_scope.canInit(var) )
+                    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);
@@ -1507,7 +1506,10 @@ 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);
@@ -1555,7 +1557,7 @@ public class Parser {
         if( instance(var) ) {
             Var selfVar = _scope.lookup("self");
             Node self = liftExpr(_scope.in(selfVar),selfVar.type(),true);
-            return parsePostfixName(self,id);
+            return parsePostfixName(self,id,pre);
         }
 
         // Load local value
@@ -1570,7 +1572,7 @@ 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
@@ -1580,7 +1582,8 @@ public class Parser {
         checkCaptureWrite(var);
         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,
@@ -1877,8 +1880,10 @@ public class Parser {
      *     expr ('[' expr ']')* [ [op]= expr ] // Array reference
      * </pre>
      */
-    private Node parsePostfixName(Node expr, String name) {
-        if( privateSelf(expr) ) return parsePrivateField(name);
+    private Node parsePostfixName(Node expr, String name) { return parsePostfixName(expr,name,0); }
+
+    private Node parsePostfixName(Node expr, String name, int pre) {
+        if( privateSelf(expr) ) return parsePrivateField(name,pre);
         if( !privateSelf(expr) && mayBeSelf(expr,new java.util.BitSet()) )
             throw error("Cannot access self through a merged alias during construction");
 
@@ -1887,7 +1892,7 @@ public class Parser {
 
         // Sanity check expr for being a reference
         if( !(expr._type instanceof TypeMemPtr ptr) )
-            return parseUnknownField(expr,name);
+            return parseUnknownField(expr,name,pre);
 
         // Find the field from the Type.  Lookup in the base object field names.
         TypeMemPtr ptr2 = (TypeMemPtr)TYPES.get(ptr._obj._name);
@@ -1895,7 +1900,7 @@ public class Parser {
             ptr = ptr.makeFrom(ptr2._obj); // The declaration fixes the field shape; retain this view's access.
         TypeStruct base = ptr._obj;
         int fidx = base.find(name);
-        if( fidx==-1 && base._open ) return parseUnknownField(expr,name);
+        if( fidx==-1 && base._open ) return parseUnknownField(expr,name,pre);
         if( fidx == -1 )
             throw error("Accessing unknown field '" + name + "' from '" + ptr.str() + "'");
 
@@ -1918,7 +1923,7 @@ 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 );
 
@@ -1937,14 +1942,16 @@ 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
@@ -1969,7 +1976,7 @@ public class Parser {
 
     // Syntax fixes the access even when a forward definition or a loop
     // leaves the receiver untyped. Resolve its alias and layout in the graph.
-    private Node parseUnknownField(Node expr, String name) {
+    private Node parseUnknownField(Node expr, String name, int pre) {
         expr.keep();
         Node off = new FldOffNode(expr,name).peephole();
         if( name.equals("[]") ) {
@@ -1978,7 +1985,7 @@ public class Parser {
             off = peep(new AddNode(off,peep(new ShlNode(loc(),index,scale))));
         }
         off.keep();
-        if( matchOpx('=','=') ) {
+        if( pre==0 && matchOpx('=','=') ) {
             Node value = parseAsgn().keep();
             unknownStore(name,expr,off,value);
             expr.unkill();
@@ -1988,7 +1995,7 @@ public class Parser {
         Node load = new LoadNode(loc(),name,1,mem(),expr,off);
         load.setDef(0,ctrl());
         load = peep(load);
-        char ch = _lexer.matchOperAssign();
+        char ch = pre==0 ? _lexer.matchOperAssign() : (char)pre;
         if( ch!=0 ) {
             Node op = opAssign(ch,load,Type.BOTTOM).keep();
             unknownStore(name,expr,off,op);
@@ -1996,7 +2003,7 @@ public class Parser {
             // the stored value after conversion; postfix returns the old load.
             // Reading our own Store folds once its alias and width are known.
             if( postfix(ch) ) load.unkeep();
-            else {
+            if( pre!=0 || !postfix(ch) ) {
                 load = new LoadNode(loc(),name,1,mem(),expr,off);
                 load.setDef(0,ctrl());
                 load = peep(load);
@@ -2010,7 +2017,7 @@ public class Parser {
         } else load.keep();
         expr.unkill();
         off.unkill();
-        return parsePostfix(load.unkeep());
+        return pre==0 ? parsePostfix(load.unkeep()) : load.unkeep();
     }
 
     private void unknownStore(String name, Node ptr, Node off, Node value) {
@@ -2022,12 +2029,12 @@ public class Parser {
 
     // Explicit self.x and an unqualified field name use the same local slot.
     // The map also keeps self.x distinct from a parameter/local named x.
-    private Node parsePrivateField(String name) {
+    private Node parsePrivateField(String name, int pre) {
         Var v=_fieldVars.get(name);
         if( v==null ) throw error("Cannot resolve field '"+name+"'");
         if( v.type() instanceof TypeFunPtr ctor && ctor.ret() instanceof TypeMem )
             throw error("A constructor is only called by new");
-        if( matchOpx('=','=') ) {
+        if( pre==0 && matchOpx('=','=') ) {
             checkPrivateWrite(name);
             Node value=parseAsgn().keep();
             checkPublication(value);
@@ -2037,13 +2044,14 @@ public class Parser {
         Node value=_scope.in(_scope.update(v,null));
         if( value instanceof ConstantNode && (value._type==Type.BOTTOM || value._type==Type.TOP) )
             throw error("Cannot read uninitialized field '"+name+"'");
-        char ch=_lexer.matchOperAssign();
+        char ch=pre==0 ? _lexer.matchOperAssign() : (char)pre;
         if( ch!=0 ) {
             checkPrivateWrite(name);
             Node op=opAssign(ch,value,v.type());
             checkPublication(op);
             _scope.update(v,op);
-            return postfix(ch) ? value.unkeep() : op;
+            if( postfix(ch) ) value.unkeep();
+            return pre==0 && postfix(ch) ? value : op;
         }
         if( value._type instanceof TypeFunPtr && match("(") )
             return parsePostfix(require(functionCall(value,self()),")"));
diff --git a/chapter27/src/test/java/com/seaofnodes/simple/PrefixUpdateTest.java b/chapter27/src/test/java/com/seaofnodes/simple/PrefixUpdateTest.java
new file mode 100644
index 00000000..56d553b3
--- /dev/null
+++ b/chapter27/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);
+    }
+}