revert & to untyped pointer, added && for typed pointer address-of

compiler/src/prog8/compiler/astprocessing/BeforeAsmTypecastCleaner.kt

@@ -39,14 +39,14 @@ internal class BeforeAsmTypecastCleaner(val program: Program,
                         listOf(IAstModification.ReplaceNode(typecast, typecast.expression, parent))
                     } else {
                         listOf(IAstModification.ReplaceNode(typecast,
-                            AddressOf(identifier, null, null, false, typecast.position), parent))
+                            AddressOf(identifier, null, null, false, false,typecast.position), parent))
                     }
                 } else if (typecast.expression is IFunctionCall) {
                     return listOf(IAstModification.ReplaceNode(typecast, typecast.expression, parent))
                 }
             } else if(sourceDt.isString && typecast.type.isPointer && typecast.type.sub==BaseDataType.UBYTE) {
                 // casting a string to a ^^ubyte is just taking the address of the string.
-                val addr = AddressOf(typecast.expression as IdentifierReference, null, null, false, typecast.position)
+                val addr = AddressOf(typecast.expression as IdentifierReference, null, null, false, true, typecast.position)
                 return listOf(IAstModification.ReplaceNode(typecast, addr, parent))
             } else {
                 errors.err("cannot cast pass-by-reference value to type ${typecast.type} (only to UWORD)", typecast.position)

compiler/src/prog8/compiler/astprocessing/TypecastsAdder.kt

@@ -317,7 +317,7 @@ class TypecastsAdder(val program: Program, val options: CompilationOptions, val
                             if(!argDt.isString || it.second is IdentifierReference) {
                                 modifications += IAstModification.ReplaceNode(
                                     identifier,
-                                    AddressOf(identifier, null, null, false, it.second.position),
+                                    AddressOf(identifier, null, null, false, true, it.second.position),
                                     call as Node
                                 )
                             }
@@ -337,7 +337,7 @@ class TypecastsAdder(val program: Program, val options: CompilationOptions, val
                         // take the address of the identifier
                         modifications += IAstModification.ReplaceNode(
                             identifier,
-                            AddressOf(identifier, null, null, false, it.second.position),
+                            AddressOf(identifier, null, null, false, false,it.second.position),
                             call as Node
                         )
                     } else if(dt.isUnknown) {
@@ -346,7 +346,7 @@ class TypecastsAdder(val program: Program, val options: CompilationOptions, val
                             // take the address of the subroutine or label
                             modifications += IAstModification.ReplaceNode(
                                 identifier,
-                                AddressOf(identifier, null, null, false, it.second.position),
+                                AddressOf(identifier, null, null, false, false, it.second.position),
                                 call as Node
                             )
                         }
@@ -481,7 +481,7 @@ class TypecastsAdder(val program: Program, val options: CompilationOptions, val
                 val eltType = elt.inferType(program)
                 val tgt = elt.targetStatement()
                 if(eltType.isIterable || tgt is Subroutine || tgt is Label || tgt is Block)  {
-                    val addressof = AddressOf(elt, null, null, false, elt.position)
+                    val addressof = AddressOf(elt, null, null, false, false, elt.position)
                     addressof.linkParents(array)
                     array.value[index] = addressof
                 }

compiler/test/TestPointers.kt

@@ -12,9 +12,7 @@ import prog8.ast.expressions.ArrayIndexedExpression
 import prog8.ast.expressions.DirectMemoryRead
 import prog8.ast.expressions.PtrDereference
 import prog8.ast.statements.*
-import prog8.code.ast.PtAssignment
+import prog8.code.ast.*
-import prog8.code.ast.PtReturn
-import prog8.code.ast.PtSubSignature
 import prog8.code.core.BaseDataType
 import prog8.code.core.DataType
 import prog8.code.core.IMemSizer
@@ -585,7 +583,7 @@ main {
         }
     }
 
-    test("type of & operator (address-of)") {
+    test("internal type for address-of") {
         DataType.BYTE.typeForAddressOf(false) shouldBe DataType.pointer(BaseDataType.BYTE)
         DataType.WORD.typeForAddressOf(false) shouldBe DataType.pointer(BaseDataType.WORD)
         DataType.FLOAT.typeForAddressOf(false) shouldBe DataType.pointer(BaseDataType.FLOAT)
@@ -605,6 +603,31 @@ main {
         DataType.pointer(BaseDataType.BOOL).typeForAddressOf(false) shouldBe DataType.UWORD
     }
 
+    test("untyped and typed address-of operators") {
+        val src="""
+%option enable_floats
+
+main {
+    sub start() {
+        float f
+        cx16.r0 = &f+1
+        cx16.r1 = &&f+1
+    }
+}"""
+
+        val result = compileText(VMTarget(), false, src, outputDir, writeAssembly = true)!!
+        val st = result.codegenAst!!.entrypoint()!!.children
+        st.size shouldBe 6
+        val r0v = (st[3] as PtAssignment).value as PtBinaryExpression
+        val r1v = (st[4] as PtAssignment).value as PtBinaryExpression
+        r0v.left shouldBe instanceOf<PtAddressOf>()
+        r0v.right shouldBe instanceOf<PtNumber>()
+        (r0v.right as PtNumber).number shouldBe 1.0
+        r1v.left shouldBe instanceOf<PtAddressOf>()
+        r1v.right shouldBe instanceOf<PtNumber>()
+        (r1v.right as PtNumber).number shouldBe VMTarget.FLOAT_MEM_SIZE
+    }
+
     test("address-of struct fields") {
         val src="""
 %option enable_floats
@@ -1375,7 +1398,7 @@ main {
         val errors = ErrorReporterForTests()
         compileText(VMTarget(), false, src, outputDir, errors = errors) shouldBe null
         errors.errors.size shouldBe 999
-        // TODO
+        // TODO implement this test
     }
 
     xtest("array of pointers as subroutine param") {

compiler/test/codegeneration/TestAsmGenSymbols.kt

@@ -65,13 +65,13 @@ class TestAsmGenSymbols: StringSpec({
             position = Position.DUMMY
         )
         val assign1 = Assignment(tgt, IdentifierReference(listOf("localvar"), Position.DUMMY), AssignmentOrigin.USERCODE, Position.DUMMY)
-        val assign2 = Assignment(tgt, AddressOf(IdentifierReference(listOf("locallabel"), Position.DUMMY), null, null, false, Position.DUMMY), AssignmentOrigin.USERCODE, Position.DUMMY)
+        val assign2 = Assignment(tgt, AddressOf(IdentifierReference(listOf("locallabel"), Position.DUMMY), null, null, false, false, Position.DUMMY), AssignmentOrigin.USERCODE, Position.DUMMY)
-        val assign3 = Assignment(tgt, AddressOf(IdentifierReference(listOf("var_outside"), Position.DUMMY), null, null, false, Position.DUMMY), AssignmentOrigin.USERCODE, Position.DUMMY)
+        val assign3 = Assignment(tgt, AddressOf(IdentifierReference(listOf("var_outside"), Position.DUMMY), null, null, false, false, Position.DUMMY), AssignmentOrigin.USERCODE, Position.DUMMY)
-        val assign4 = Assignment(tgt, AddressOf(IdentifierReference(listOf("label_outside"), Position.DUMMY), null, null, false, Position.DUMMY), AssignmentOrigin.USERCODE, Position.DUMMY)
+        val assign4 = Assignment(tgt, AddressOf(IdentifierReference(listOf("label_outside"), Position.DUMMY), null, null, false, false, Position.DUMMY), AssignmentOrigin.USERCODE, Position.DUMMY)
-        val assign5 = Assignment(tgt, AddressOf(IdentifierReference(listOf("main","start","localvar"), Position.DUMMY), null, null, false, Position.DUMMY), AssignmentOrigin.USERCODE, Position.DUMMY)
+        val assign5 = Assignment(tgt, AddressOf(IdentifierReference(listOf("main","start","localvar"), Position.DUMMY), null, null, false, false, Position.DUMMY), AssignmentOrigin.USERCODE, Position.DUMMY)
-        val assign6 = Assignment(tgt, AddressOf(IdentifierReference(listOf("main","start","locallabel"), Position.DUMMY), null, null, false, Position.DUMMY), AssignmentOrigin.USERCODE, Position.DUMMY)
+        val assign6 = Assignment(tgt, AddressOf(IdentifierReference(listOf("main","start","locallabel"), Position.DUMMY), null, null, false, false, Position.DUMMY), AssignmentOrigin.USERCODE, Position.DUMMY)
-        val assign7 = Assignment(tgt, AddressOf(IdentifierReference(listOf("main","var_outside"), Position.DUMMY), null, null, false, Position.DUMMY), AssignmentOrigin.USERCODE, Position.DUMMY)
+        val assign7 = Assignment(tgt, AddressOf(IdentifierReference(listOf("main","var_outside"), Position.DUMMY), null, null, false, false, Position.DUMMY), AssignmentOrigin.USERCODE, Position.DUMMY)
-        val assign8 = Assignment(tgt, AddressOf(IdentifierReference(listOf("main","label_outside"), Position.DUMMY), null, null, false, Position.DUMMY), AssignmentOrigin.USERCODE, Position.DUMMY)
+        val assign8 = Assignment(tgt, AddressOf(IdentifierReference(listOf("main","label_outside"), Position.DUMMY), null, null, false, false, Position.DUMMY), AssignmentOrigin.USERCODE, Position.DUMMY)
 
         val statements = mutableListOf(varInSub, var2InSub, labelInSub, assign1, assign2, assign3, assign4, assign5, assign6, assign7, assign8)
         val subroutine = Subroutine("start", mutableListOf(), mutableListOf(), emptyList(), emptyList(), emptySet(), null, false, false, false, statements, Position.DUMMY)

compilerAst/src/prog8/ast/antlr/Antlr2KotlinVisitor.kt

@@ -280,10 +280,17 @@ class Antlr2KotlinVisitor(val source: SourceCode): AbstractParseTreeVisitor<Node
         val msb = ctx.ADDRESS_OF_MSB()!=null
         // note: &<  (ADDRESS_OF_LSB)  is equivalent to a regular &.
         val index = ctx.arrayindex()?.accept(this) as? ArrayIndex
-        return if(index!=null) {
+        var typed = false
-            AddressOf(identifier, index, null, msb, ctx.toPosition())
+        if(ctx.TYPED_ADDRESS_OF()!=null) {
+            // new typed AddressOf
+            if(msb)
+                throw SyntaxError("typed address of not allowed with msb", ctx.toPosition())
+            typed = true
+        }
+        return if (index != null) {
+            AddressOf(identifier, index, null, msb, typed, ctx.toPosition())
         } else {
-            AddressOf(identifier,null, null, msb, ctx.toPosition())
+            AddressOf(identifier, null, null, msb, typed, ctx.toPosition())
         }
     }
 

compilerAst/src/prog8/ast/expressions/AstExpressions.kt

@@ -502,7 +502,8 @@ class TypecastExpression(var expression: Expression, var type: DataType, val imp
     }
 }
 
-data class AddressOf(var identifier: IdentifierReference?, var arrayIndex: ArrayIndex?, var dereference: PtrDereference?, val msb: Boolean, override val position: Position) : Expression() {
+data class AddressOf(var identifier: IdentifierReference?, var arrayIndex: ArrayIndex?, var dereference: PtrDereference?,
+                     val msb: Boolean, val typed: Boolean, override val position: Position) : Expression() {
     override lateinit var parent: Node
 
     override fun linkParents(parent: Node) {
@@ -538,7 +539,7 @@ data class AddressOf(var identifier: IdentifierReference?, var arrayIndex: Array
         replacement.parent = this
     }
 
-    override fun copy() = AddressOf(identifier?.copy(), arrayIndex?.copy(), dereference?.copy(), msb, position)
+    override fun copy() = AddressOf(identifier?.copy(), arrayIndex?.copy(), dereference?.copy(), msb, typed, position)
     override fun constValue(program: Program): NumericLiteral? {
         if(msb)
             return null
@@ -574,8 +575,9 @@ data class AddressOf(var identifier: IdentifierReference?, var arrayIndex: Array
         return null
     }
     override fun referencesIdentifier(nameInSource: List<String>) = identifier?.nameInSource==nameInSource || arrayIndex?.referencesIdentifier(nameInSource)==true || dereference?.referencesIdentifier(nameInSource)==true
-//    override fun inferType(program: Program): InferredTypes.InferredType = InferredTypes.knownFor(BaseDataType.UWORD)   // TODO orignal behavior
     override fun inferType(program: Program): InferredTypes.InferredType {
+        if(!typed)
+            return InferredTypes.knownFor(BaseDataType.UWORD)   // orignal pre-v12 untyped AddressOf
         if(identifier!=null) {
             val type = identifier!!.inferType(program).getOrUndef()
             val addrofDt = type.typeForAddressOf(msb)

compilerAst/src/prog8/ast/statements/AstStatements.kt

@@ -270,7 +270,7 @@ class VarDecl(
                 // parameter variable memory mapped to a R0-R15 virtual register
                 val regname = param.registerOrPair.asScopedNameVirtualReg(param.type)
                 decltype = VarDeclType.MEMORY
-                value = AddressOf(IdentifierReference(regname, param.position), null, null, false, param.position)
+                value = AddressOf(IdentifierReference(regname, param.position), null, null, false, false,param.position)
             }
             val dt = if(param.type.isArray) DataType.UWORD else param.type
             return VarDecl(decltype, VarDeclOrigin.SUBROUTINEPARAM, dt, param.zp, SplitWish.DONTCARE, null, param.name, emptyList(), value,

docs/source/programming.rst

@@ -999,7 +999,7 @@ containment check:  ``in``
         }
 
 
-address of:  ``&``,   ``&<``,   ``&>``
+address of:  ``&``,   ``&<``,   ``&>``,   ``&&``
     This is a prefix operator that can be applied to a string or array variable or literal value.
     It results in the memory address (UWORD) of that string or array in memory:  ``uword a = &stringvar``
     Sometimes the compiler silently inserts this operator to make it easier for instance
@@ -1012,6 +1012,11 @@ address of:  ``&``,   ``&<``,   ``&>``
     and MSB byte array separately, respectively.   Note that ``&<`` is just the same as ``&`` in this case.
     For more details on split word arrays, see :ref:`arrayvars`.
 
+    **Typed pointer version:** the single ``&`` operator still returns an untyped uword address for
+    backward compatibility reasons, so existing programs keep working. The *double ampersand* ``&&`` operator
+    however returns a *typed* pointer to the value. The semantics are slightly different because adding or subtracting
+    a number from a typed pointer uses *pointer arithmetic* that takes the size of the value that it points to into account.
+
 
 ternary:
     Prog8 doesn't have a ternary operator to choose one of two values (``x? y : z`` in many other languages)

docs/source/structpointers.rst

@@ -81,3 +81,11 @@ Typed pointer to Struct type
 ----------------------------
 
 Work in progress.
+
+
+Address-Of: untyped vs typed
+----------------------------
+
+``&`` still returns untyped (uword) pointer, as it did in older Prog8 versions. This is for backward compatibility reasons so existing programs don't break.
+The *double ampersand* operator ``&&`` returns a *typed* pointer to the value. The semantics are slightly different from the old untyped address-of operator, because adding or subtracting
+a number from a typed pointer uses *pointer arithmetic* that takes the size of the value that it points to into account.

docs/source/todo.rst

@@ -1,10 +1,6 @@
 TODO
 ====
 
-What to do with the changed adress-of behavior? &x now returns a typed pointer to &x + 10 will now be calculated differently (C pointer arithmetic semantics rather than simply byte addition)
-compiler flag to select old behavior? new operator that has the new behavior?    Don't want to break existing code that used &....
-Old behavior can be put back by always returning UWORD as the inferred type for AddressOf nodes
-
 
 STRUCTS and TYPED POINTERS
 --------------------------
@@ -58,6 +54,7 @@ STRUCTS and TYPED POINTERS
 - DONE: fix _msb/_lsb storage of the split-words pointer-arrays
 - DONE: what about static initialization of an array of struct pointers? -> impossible right now because the pointer values are not constants.
 - DONE: make typeForAddressOf() be even more specific about the typed pointers it returns for the address-of operator.
+- DONE: existing '&' address-of still returns untyped uword (for backward compatibility). New '&&' operator returns typed pointer.
 - DONE: allow  list1^^ = list2^^  (value wise assignment of List structures) by replacing it with a sys.memcopy(list2, list1, sizeof(List)) call.
 - DONE: allow  a.b.ptr[i].value  (equiv to a.b.ptr[i]^^.value)  expressions  (assignment target doesn't parse yet, see below)
 - DONE: check passing arrays to typed ptr sub-parameters.  NOTE: word array can only be a @nosplit array if the parameter type is ^^word, because the words need to be sequential in memory there

examples/test.p8

@@ -5,48 +5,23 @@
 
 main {
 
-    ubyte @shared thingIndex = 10
-    uword[20] @shared dummy
-    uword[10] @split curframesplit
-    uword[10] @nosplit curframe
-    uword p1, p2
     float f
 
     sub start() {
-        classic()
+        txt.print("classic float pointer+1: ")
-        ; new()
-    }
-
-    sub classic() {
-        txt.print("float pointer+1: ")
         txt.print_uwhex(&f, true)
         txt.spc()
         txt.print_uwhex(&f + 1, true)
+        txt.spc()
+        txt.print_uw(&f + 1 - &f)
         txt.nl()
 
-        p1 = &curframesplit[thingIndex]
+        txt.print("typed float pointer+1: ")
-        p2 = &curframe[thingIndex]
+        txt.print_uwhex(&&f, true)
-
-        txt.print("&array (split): ")
-        txt.print_uwhex(&curframesplit, true)
         txt.spc()
-        txt.print_uwhex(p1, true)
+        txt.print_uwhex(&&f + 1, true)
         txt.spc()
-        txt.print_uw(p1 - &curframesplit)
+        txt.print_uw(&&f + 1 - &&f)
-        txt.spc()
-        txt.print_uwhex(p1 + &curframesplit, true)
-        txt.nl()
-
-        txt.print("&array (normal): ")
-        txt.print_uwhex(&curframe, true)
-        txt.spc()
-        txt.print_uwhex(p2, true)
-        txt.spc()
-        txt.print_uw(p2 - &curframe)
-        txt.spc()
-        txt.print_uwhex(p2 + &curframe, true)
         txt.nl()
     }
-
-    ; 6502 data size: $0251
 }

parser/src/main/antlr/Prog8ANTLR.g4

@@ -37,9 +37,9 @@ DEC_INTEGER :  DEC_DIGIT (DEC_DIGIT | '_')* ;
 HEX_INTEGER :  '$' HEX_DIGIT (HEX_DIGIT | '_')* ;
 BIN_INTEGER :  '%' BIN_DIGIT (BIN_DIGIT | '_')* ;
 ADDRESS_OF: '&' ;
+TYPED_ADDRESS_OF: '&&' ;
 ADDRESS_OF_MSB: '&>' ;
 ADDRESS_OF_LSB: '&<' ;
-INVALID_AND_COMPOSITE: '&&' ;
 POINTER: '^^';
 
 fragment HEX_DIGIT: ('a'..'f') | ('A'..'F') | ('0'..'9') ;
@@ -241,7 +241,7 @@ typecast : 'as' datatype;
 
 directmemory : '@' '(' expression ')';
 
-addressof : <assoc=right> (ADDRESS_OF | ADDRESS_OF_LSB | ADDRESS_OF_MSB) scoped_identifier arrayindex? ;
+addressof : <assoc=right> (ADDRESS_OF | TYPED_ADDRESS_OF | | ADDRESS_OF_LSB | ADDRESS_OF_MSB) scoped_identifier arrayindex? ;
 
 functioncall : scoped_identifier '(' expression_list? ')'  ;