fixed 'unroll CONSTANTEXPR' compiler errors

codeOptimizers/src/prog8/optimizer/ConstantFoldingOptimizer.kt

@@ -628,5 +628,4 @@ class ConstantFoldingOptimizer(private val program: Program) : AstWalker() {
             return null
         }
     }
-
 }

codeOptimizers/src/prog8/optimizer/StatementOptimizer.kt

@@ -384,7 +384,8 @@ class StatementOptimizer(private val program: Program,
     }
 
     override fun before(unrollLoop: UnrollLoop, parent: Node): Iterable<IAstModification> {
-        return if(unrollLoop.iterations<1)
+        val iterations = unrollLoop.iterations.constValue(program)?.number?.toInt()
+        return if(iterations!=null && iterations<1)
             listOf(IAstModification.Remove(unrollLoop, parent as IStatementContainer))
         else
             noModifications

compiler/src/prog8/compiler/astprocessing/AstChecker.kt

@@ -76,14 +76,19 @@ internal class AstChecker(private val program: Program,
     }
 
     override fun visit(unrollLoop: UnrollLoop) {
-        if(unrollLoop.iterations<0 || unrollLoop.iterations>65535)
-            errors.err("invalid number of unrolls", unrollLoop.position)
-        unrollLoop.body.statements.forEach {
-            if(it !is InlineAssembly && it !is Assignment && it !is BuiltinFunctionCallStatement && it !is FunctionCallStatement && it !is PostIncrDecr)
-                errors.err("invalid statement in unroll loop", it.position)
-        }
-        if(unrollLoop.iterations * unrollLoop.body.statements.size > 256) {
-            errors.warn("large number of unrolls, potential code size issue", unrollLoop.position)
+        val iterations = unrollLoop.iterations.constValue(program)?.number?.toInt()
+        if(iterations==null) {
+            errors.err("unroll needs constant number of iterations", unrollLoop.position)
+        } else {
+            if (iterations < 0 || iterations > 65535)
+                errors.err("invalid number of unrolls", unrollLoop.position)
+            unrollLoop.body.statements.forEach {
+                if (it !is InlineAssembly && it !is Assignment && it !is BuiltinFunctionCallStatement && it !is FunctionCallStatement && it !is PostIncrDecr)
+                    errors.err("invalid statement in unroll loop", it.position)
+            }
+            if (iterations * unrollLoop.body.statements.size > 256) {
+                errors.warn("large number of unrolls, potential code size issue", unrollLoop.position)
+            }
         }
         super.visit(unrollLoop)
     }

compiler/src/prog8/compiler/astprocessing/IntermediateAstMaker.kt

@@ -326,7 +326,7 @@ class IntermediateAstMaker(private val program: Program) {
 
     private fun transform(srcUnroll: UnrollLoop): PtNodeGroup {
         val result = PtNodeGroup()
-        repeat(srcUnroll.iterations) {
+        repeat(srcUnroll.iterations.constValue(program)!!.number.toInt()) {
             srcUnroll.body.statements.forEach {
                 result.add(transformStatement(it))
             }

compilerAst/src/prog8/ast/antlr/Antlr2Kotlin.kt

@@ -583,7 +583,7 @@ private fun Prog8ANTLRParser.RepeatloopContext.toAst(): RepeatLoop {
 }
 
 private fun Prog8ANTLRParser.UnrollloopContext.toAst(): UnrollLoop {
-    val iterations = integerliteral().toAst().number.toInt()
+    val iterations = expression().toAst()
     val statements = statement_block()?.toAst() ?: mutableListOf(statement().toAst())
     val scope = AnonymousScope(statements, statement_block()?.toPosition()
         ?: statement().toPosition())

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

@@ -931,25 +931,28 @@ class RepeatLoop(var iterations: Expression?, var body: AnonymousScope, override
         iterations?.referencesIdentifier(nameInSource)==true || body.referencesIdentifier(nameInSource)
 }
 
-class UnrollLoop(val iterations: Int, var body: AnonymousScope, override val position: Position) : Statement() {
+class UnrollLoop(var iterations: Expression, var body: AnonymousScope, override val position: Position) : Statement() {
+    // note: the iterations needs to evaluate to a constant number once parsed.
     override lateinit var parent: Node
 
     override fun linkParents(parent: Node) {
         this.parent = parent
+        iterations.linkParents(this)
         body.linkParents(this)
     }
 
     override fun copy() = throw NotImplementedError("no support for duplicating an UnrollLoop")
 
     override fun replaceChildNode(node: Node, replacement: Node) {
         if (node===body) body = replacement as AnonymousScope
+        else if (node===iterations) iterations = replacement as Expression
         else throw FatalAstException("invalid replace")
         replacement.parent = this
     }
 
     override fun accept(visitor: IAstVisitor) = visitor.visit(this)
     override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
-    override fun referencesIdentifier(nameInSource: List<String>): Boolean = body.referencesIdentifier(nameInSource)
+    override fun referencesIdentifier(nameInSource: List<String>): Boolean = iterations.referencesIdentifier(nameInSource) || body.referencesIdentifier(nameInSource)
 }
 
 class UntilLoop(var body: AnonymousScope,

compilerAst/src/prog8/ast/walk/AstWalker.kt

@@ -398,6 +398,7 @@ abstract class AstWalker {
 
     fun visit(unrollLoop: UnrollLoop, parent: Node) {
         track(before(unrollLoop, parent), unrollLoop, parent)
+        unrollLoop.iterations.accept(this, unrollLoop)
         unrollLoop.body.accept(this, unrollLoop)
         track(after(unrollLoop, parent), unrollLoop, parent)
     }

docs/source/todo.rst

@@ -1,9 +1,6 @@
 TODO
 ====
 
-- fix compiler crash on "unroll for x in 0 to txt.DEFAULT_WIDTH-1"
-- fix compiler error on "unroll txt.DEFAULT_WIDTH"
-
 - prefix prog8 subroutines with p8s_ instead of p8_ to not let them clash with variables in the asm??
 - [on branch: shortcircuit] investigate McCarthy evaluation again? this may also reduce code size perhaps for things like if a>4 or a<2 ....
 - IR: reduce the number of branch instructions such as BEQ, BEQR, etc (gradually), replace with CMP(I) + status branch instruction

examples/test.p8

@@ -1,22 +1,15 @@
 %import textio
-%zeropage basicsafe
+%zeropage dontuse
 
 main {
     sub start() {
+        const ubyte CONSTANT=80
+        cx16.r0 = 0
+        unroll CONSTANT-10 {
+            cx16.r0++
+        }
+        txt.print_uw(cx16.r0)
 
-        ubyte[5] xx = [11,22,33,44,55]
-        ubyte[5] yy = [101,102,103,104,105]
-        ubyte i=3
-        ubyte j = 4
-        uword screen
-
-        ubyte result = xx[i] + yy[j]
-        txt.print_ub(result)    ; 149
-        txt.nl()
-        result = xx[i] + yy[i]
-        txt.print_ub(result)    ; 148
-        txt.nl()
-        @(screen+i) = xx[i] + yy[i]
 
 ;        ubyte index = 100
 ;        ubyte[] t_index = [1,2,3,4,5]

parser/antlr/Prog8ANTLR.g4

@@ -299,7 +299,7 @@ untilloop:  'do' (statement | statement_block) EOL? 'until' expression ;
 
 repeatloop:  'repeat' expression? EOL? (statement | statement_block) ;
 
-unrollloop:  'unroll' integerliteral? EOL? (statement | statement_block) ;
+unrollloop:  'unroll' expression EOL? (statement | statement_block) ;      // note: expression must evaluate to a constant
 
 whenstmt: 'when' expression EOL? '{' EOL? (when_choice | EOL) * '}' EOL? ;