preparing optimizing pointer indexing

compiler/src/prog8/compiler/astprocessing/AstVariousTransforms.kt

@@ -3,19 +3,16 @@ package prog8.compiler.astprocessing
 import prog8.ast.Node
 import prog8.ast.Program
 import prog8.ast.expressions.ArrayIndexedExpression
-import prog8.ast.expressions.BinaryExpression
-import prog8.ast.expressions.DirectMemoryRead
-import prog8.ast.statements.AssignTarget
-import prog8.ast.statements.DirectMemoryWrite
 import prog8.ast.statements.Subroutine
 import prog8.ast.statements.VarDecl
 import prog8.ast.walk.AstWalker
 import prog8.ast.walk.IAstModification
-import prog8.code.core.DataType
 
 
 internal class AstVariousTransforms(private val program: Program) : AstWalker() {
 
+    // TODO can this be integrated in another walker
+
     override fun after(subroutine: Subroutine, parent: Node): Iterable<IAstModification> {
         // For non-kernal subroutines and non-asm parameters:
         // inject subroutine params as local variables (if they're not there yet).
@@ -38,29 +35,8 @@ internal class AstVariousTransforms(private val program: Program) : AstWalker()
         return noModifications
     }
 
+    // TODO move this / remove this.  Needed here atm otherwise a replacement error occurs later in StatementReorderer
     override fun after(arrayIndexedExpression: ArrayIndexedExpression, parent: Node): Iterable<IAstModification> {
         return replacePointerVarIndexWithMemreadOrMemwrite(program, arrayIndexedExpression, parent)
     }
 }
-
-
-
-internal fun replacePointerVarIndexWithMemreadOrMemwrite(program: Program, arrayIndexedExpression: ArrayIndexedExpression, parent: Node): Iterable<IAstModification> {
-    val arrayVar = arrayIndexedExpression.arrayvar.targetVarDecl(program)
-    if(arrayVar!=null && arrayVar.datatype == DataType.UWORD) {
-        // rewrite   pointervar[index]  into  @(pointervar+index)
-        val indexer = arrayIndexedExpression.indexer
-        val add = BinaryExpression(arrayIndexedExpression.arrayvar.copy(), "+", indexer.indexExpr, arrayIndexedExpression.position)
-        return if(parent is AssignTarget) {
-            // we're part of the target of an assignment, we have to actually change the assign target itself
-            val memwrite = DirectMemoryWrite(add, arrayIndexedExpression.position)
-            val newtarget = AssignTarget(null, null, memwrite, arrayIndexedExpression.position)
-            listOf(IAstModification.ReplaceNode(parent, newtarget, parent.parent))
-        } else {
-            val memread = DirectMemoryRead(add, arrayIndexedExpression.position)
-            listOf(IAstModification.ReplaceNode(arrayIndexedExpression, memread, parent))
-        }
-    }
-
-    return emptyList()
-}

compiler/src/prog8/compiler/astprocessing/StatementReorderer.kt

@@ -576,3 +576,25 @@ private fun makeGosubWithArgsViaCpuStack(
     }
     return listOf(IAstModification.ReplaceNode(call as Node, scope, parent))
 }
+
+
+
+internal fun replacePointerVarIndexWithMemreadOrMemwrite(program: Program, arrayIndexedExpression: ArrayIndexedExpression, parent: Node): Iterable<IAstModification> {
+    val arrayVar = arrayIndexedExpression.arrayvar.targetVarDecl(program)
+    if(arrayVar!=null && arrayVar.datatype == DataType.UWORD) {
+        // rewrite   pointervar[index]  into  @(pointervar+index)
+        val indexer = arrayIndexedExpression.indexer
+        val add = BinaryExpression(arrayIndexedExpression.arrayvar.copy(), "+", indexer.indexExpr, arrayIndexedExpression.position)
+        return if(parent is AssignTarget) {
+            // we're part of the target of an assignment, we have to actually change the assign target itself
+            val memwrite = DirectMemoryWrite(add, arrayIndexedExpression.position)
+            val newtarget = AssignTarget(null, null, memwrite, arrayIndexedExpression.position)
+            listOf(IAstModification.ReplaceNode(parent, newtarget, parent.parent))
+        } else {
+            val memread = DirectMemoryRead(add, arrayIndexedExpression.position)
+            listOf(IAstModification.ReplaceNode(arrayIndexedExpression, memread, parent))
+        }
+    }
+
+    return emptyList()
+}

compiler/test/TestOptimization.kt

@@ -757,4 +757,19 @@ class TestOptimization: FunSpec({
         val ifStmt = stmts[4] as IfElse
         ifStmt.condition shouldBe instanceOf<BinaryExpression>()
     }
+
+    test("pointer indexing inside other expression ok") {
+        val src="""
+            main{
+                sub start () {
+                    uword eRef
+                    if eRef[3] and 10  {
+                      return
+                    }
+                }
+            }"""
+        val result = compileText(C64Target(), optimize=true, src, writeAssembly=false)!!
+        val stmts = result.program.entrypoint.statements
+        stmts.size shouldBe 3
+    }
 })

docs/source/todo.rst

@@ -3,6 +3,7 @@ TODO
 
 For next release
 ^^^^^^^^^^^^^^^^
+- try to integrated AstVariousTransforms into another walker
 - why is this code so much larger:
                 uword xx
                 for xx in 0 to size-1 {

examples/test.p8

@@ -28,6 +28,13 @@ main {
 ;        txt.spc()
 ;    }
 
+    sub crash () {
+        uword eRef
+        if eRef[3] and 10  {
+          return
+        }
+    }
+
     sub start() {
         ; mcCarthy()