fix const value of AddressOf for certain types

codeOptimizers/src/prog8/optimizer/ConstantFoldingOptimizer.kt

@@ -20,6 +20,11 @@ class ConstantFoldingOptimizer(private val program: Program, private val errors:
 
     private val evaluator = ConstExprEvaluator()
 
+    override fun after(addressOf: AddressOf, parent: Node): Iterable<IAstModification> {
+        val constAddr = addressOf.constValue(program) ?: return noModifications
+        return listOf(IAstModification.ReplaceNode(addressOf, constAddr, parent))
+    }
+
     override fun before(memread: DirectMemoryRead, parent: Node): Iterable<IAstModification> {
         // @( &thing )  -->  thing  (but only if thing is a byte type!)
         val addrOf = memread.addressExpression as? AddressOf
@@ -432,6 +437,11 @@ class ConstantFoldingOptimizer(private val program: Program, private val errors:
         return noModifications
     }
 
+    override fun after(typecast: TypecastExpression, parent: Node): Iterable<IAstModification> {
+        val constValue = typecast.constValue(program) ?: return noModifications
+        return listOf(IAstModification.ReplaceNode(typecast, constValue, parent))
+    }
+
     private class ShuffleOperands(val expr: BinaryExpression,
                                   val exprOperator: String?,
                                   val subExpr: BinaryExpression,

compiler/src/prog8/compiler/astprocessing/VariousCleanups.kt

@@ -43,6 +43,10 @@ internal class VariousCleanups(val program: Program, val errors: IErrorReporter,
     }
 
     override fun after(typecast: TypecastExpression, parent: Node): Iterable<IAstModification> {
+        val constValue = typecast.constValue(program)
+        if(constValue!=null)
+            return listOf(IAstModification.ReplaceNode(typecast, constValue, parent))
+
         if(typecast.expression is NumericLiteral) {
             val value = (typecast.expression as NumericLiteral).cast(typecast.type)
             if(value.isValid)

compiler/test/ast/TestConst.kt

@@ -271,4 +271,27 @@ main {
         (assignv2 as NumericLiteral).number shouldBe 0.0
     }
 
+    test("const address-of memory mapped arrays") {
+        val src="""
+main {
+    sub start() {
+        &uword[30] wb = ${'$'}2000
+        &uword[100] array1 = ${'$'}9e00
+        &uword[30] array2 = &array1[len(wb)]
+
+        cx16.r0 = &array1           ; ${'$'}9e00
+        cx16.r1 = &array1[len(wb)]  ; ${'$'}9e3c
+        cx16.r2 = &array2           ; ${'$'}9e3c
+    }
+}"""
+        val result = compileText(Cx16Target(), false, src, writeAssembly = false)!!
+        val st = result.compilerAst.entrypoint.statements
+        st.size shouldBe 6
+        ((st[0] as VarDecl).value as NumericLiteral).number shouldBe 0x2000
+        ((st[1] as VarDecl).value as NumericLiteral).number shouldBe 0x9e00
+        ((st[2] as VarDecl).value as NumericLiteral).number shouldBe 0x9e00+2*30
+        ((st[3] as Assignment).value as NumericLiteral).number shouldBe 0x9e00
+        ((st[4] as Assignment).value as NumericLiteral).number shouldBe 0x9e00+2*30
+        ((st[5] as Assignment).value as NumericLiteral).number shouldBe 0x9e00+2*30
+    }
 })

compilerAst/src/prog8/ast/AstToSourceTextConverter.kt

@@ -444,7 +444,11 @@ class AstToSourceTextConverter(val output: (text: String) -> Unit, val program:
     override fun visit(addressOf: AddressOf) {
         output("&")
         addressOf.identifier.accept(this)
-        addressOf.arrayIndex?.accept(this)
+        if(addressOf.arrayIndex!=null) {
+            output("[")
+            addressOf.arrayIndex?.accept(this)
+            output("]")
+        }
     }
 
     override fun visit(inlineAssembly: InlineAssembly) {

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

@@ -408,9 +408,17 @@ data class AddressOf(var identifier: IdentifierReference, var arrayIndex: ArrayI
     override fun constValue(program: Program): NumericLiteral? {
         val target = this.identifier.targetStatement(program) as? VarDecl
         if(target?.type==VarDeclType.MEMORY) {
-            val address = target.value?.constValue(program)
-            if(address!=null)
-                return NumericLiteral(DataType.UWORD, address.number, position)
+            var address = target.value?.constValue(program)?.number
+            if(address!=null) {
+                if(arrayIndex!=null) {
+                    val index = arrayIndex?.constIndex()
+                    if (index != null)
+                        address += program.memsizer.memorySize(target.datatype, index)
+                    else
+                        return null
+                }
+                return NumericLiteral(DataType.UWORD, address, position)
+            }
         }
         return null
     }

docs/source/todo.rst

@@ -3,6 +3,8 @@ TODO
 
 IR: use SCC and SCS, to optimize some code that sets 0/1 based on carry flag status
 
+try to get rid of ArrayIndex class
+
 ...
 
 

examples/test.p8

@@ -1,17 +1,16 @@
+%import floats
 %import textio
 %zeropage basicsafe
 %option no_sysinit
 
-mpb {
-    const uword HIGH_MEMORY_START = $A000
-}
-
 main {
-    &uword[20] wa = mpb.HIGH_MEMORY_START
-;    &uword[20] wa = $A000
-
     sub start() {
-        wa[0] = "smile"
-        txt.print(wa[0])
+        &uword[30] wb = $2000
+        &uword[100] array1 = $9e00
+        &uword[30] array2 = &array1[len(wb)]
+
+        txt.print_uwhex(&array1, true)           ; $9e00
+        txt.print_uwhex(&array1[len(wb)], true)  ; $9e3c
+        txt.print_uwhex(&array2, true)           ; $9e3c
     }
 }