refactoring unused code removal and noModification

compiler/src/prog8/compiler/BeforeAsmGenerationAstChanger.kt

@@ -14,8 +14,6 @@ import prog8.compiler.target.ICompilationTarget
 
 internal class BeforeAsmGenerationAstChanger(val program: Program, val errors: IErrorReporter, private val compTarget: ICompilationTarget) : AstWalker() {
 
-    private val noModifications = emptyList<IAstModification>()
-
     override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
         subroutineVariables.add(decl.name to decl)
         if (decl.value == null && !decl.autogeneratedDontRemove && decl.type == VarDeclType.VAR && decl.datatype in NumericDatatypes) {

compiler/src/prog8/compiler/Compiler.kt

@@ -264,11 +264,16 @@ private fun processAst(programAst: Program, errors: IErrorReporter, compilerOpti
 private fun optimizeAst(programAst: Program, errors: IErrorReporter, functions: IBuiltinFunctions, compTarget: ICompilationTarget, options: CompilationOptions) {
     // optimize the parse tree
     println("Optimizing...")
+
+    val remover = UnusedCodeRemover(programAst, errors, compTarget, ::loadAsmIncludeFile)
+    remover.visit(programAst)
+    remover.applyModifications()
+
     while (true) {
         // keep optimizing expressions and statements until no more steps remain
         val optsDone1 = programAst.simplifyExpressions()
         val optsDone2 = programAst.splitBinaryExpressions(compTarget)
-        val optsDone3 = programAst.optimizeStatements(errors, functions, compTarget, ::loadAsmIncludeFile)
+        val optsDone3 = programAst.optimizeStatements(errors, functions, compTarget)
         programAst.constantFold(errors, compTarget) // because simplified statements and expressions can result in more constants that can be folded away
         errors.report()
         if (optsDone1 + optsDone2 + optsDone3 == 0)
@@ -281,9 +286,9 @@ private fun optimizeAst(programAst: Program, errors: IErrorReporter, functions:
     if(errors.noErrors()) {
         inliner.applyModifications()
         inliner.fixCallsToInlinedSubroutines()
-        val remover = UnusedCodeRemover(programAst, errors, compTarget, ::loadAsmIncludeFile)
+        val remover2 = UnusedCodeRemover(programAst, errors, compTarget, ::loadAsmIncludeFile)
-        remover.visit(programAst)
+        remover2.visit(programAst)
-        remover.applyModifications()
+        remover2.applyModifications()
     }
 
     errors.report()

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

@@ -14,7 +14,6 @@ import prog8.ast.walk.IAstModification
 
 
 internal class AstVariousTransforms(private val program: Program) : AstWalker() {
-    private val noModifications = emptyList<IAstModification>()
 
     override fun before(decl: VarDecl, parent: Node): Iterable<IAstModification> {
         // is it a struct variable? then define all its struct members as mangled names,

compiler/src/prog8/compiler/astprocessing/LiteralsToAutoVars.kt

@@ -13,7 +13,6 @@ import prog8.ast.walk.IAstModification
 
 
 internal class LiteralsToAutoVars(private val program: Program) : AstWalker() {
-    private val noModifications = emptyList<IAstModification>()
 
     override fun after(string: StringLiteralValue, parent: Node): Iterable<IAstModification> {
         if(string.parent !is VarDecl && string.parent !is WhenChoice) {

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

@@ -26,7 +26,6 @@ internal class StatementReorderer(val program: Program, val errors: IErrorReport
     // - sorts the choices in when statement.
     // - insert AddressOf (&) expression where required (string params to a UWORD function param etc).
 
-    private val noModifications = emptyList<IAstModification>()
     private val directivesToMove = setOf("%output", "%launcher", "%zeropage", "%zpreserved", "%address", "%option")
 
     override fun after(module: Module, parent: Node): Iterable<IAstModification> {

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

@@ -18,8 +18,6 @@ class TypecastsAdder(val program: Program, val errors: IErrorReporter) : AstWalk
      * (this includes function call arguments)
      */
 
-    private val noModifications = emptyList<IAstModification>()
-
     override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
         val declValue = decl.value
         if(decl.type==VarDeclType.VAR && declValue!=null && decl.struct==null) {

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

@@ -13,7 +13,6 @@ import prog8.compiler.IErrorReporter
 
 
 internal class VariousCleanups(val errors: IErrorReporter): AstWalker() {
-    private val noModifications = emptyList<IAstModification>()
 
     override fun before(nopStatement: NopStatement, parent: Node): Iterable<IAstModification> {
         return listOf(IAstModification.Remove(nopStatement, parent as INameScope))

compiler/src/prog8/optimizer/BinExprSplitter.kt

@@ -12,7 +12,6 @@ import prog8.compiler.target.ICompilationTarget
 
 
 internal class BinExprSplitter(private val program: Program, private val compTarget: ICompilationTarget) : AstWalker() {
-    private val noModifications = emptyList<IAstModification>()
 
 //    override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
 // TODO somehow if we do this, the resulting code for some programs (cube3d.p8) gets hundreds of bytes larger...:

compiler/src/prog8/optimizer/CallGraph.kt

@@ -1,24 +1,16 @@
 package prog8.optimizer
 
-import prog8.ast.INameScope
 import prog8.ast.Module
 import prog8.ast.Node
 import prog8.ast.Program
-import prog8.ast.base.DataType
-import prog8.ast.base.ParentSentinel
 import prog8.ast.base.Position
 import prog8.ast.expressions.AddressOf
 import prog8.ast.expressions.FunctionCall
-import prog8.ast.expressions.IdentifierReference
 import prog8.ast.statements.*
 import prog8.ast.walk.IAstVisitor
 import prog8.compiler.IErrorReporter
 import java.nio.file.Path
 
-private val alwaysKeepSubroutines = setOf(
-        Pair("main", "start")
-)
-
 private val asmJumpRx = Regex("""[\-+a-zA-Z0-9_ \t]+(jmp|jsr|bra)[ \t]+(\S+).*""", RegexOption.IGNORE_CASE)
 private val asmRefRx = Regex("""[\-+a-zA-Z0-9_ \t]+(...)[ \t]+(\S+).*""", RegexOption.IGNORE_CASE)
 
@@ -30,25 +22,10 @@ class CallGraph(private val program: Program, private val asmFileLoader: (filena
     val calls = mutableMapOf<Subroutine, List<Subroutine>>().withDefault { mutableListOf() }
     val calledBy = mutableMapOf<Subroutine, List<Node>>().withDefault { mutableListOf() }
 
-    // TODO  add dataflow graph: what statements use what variables - can be used to eliminate unused vars
-    val usedSymbols = mutableSetOf<Statement>()
-
     init {
         visit(program)
     }
 
-    fun forAllSubroutines(scope: INameScope, sub: (s: Subroutine) -> Unit) {
-        fun findSubs(scope: INameScope) {
-            scope.statements.forEach {
-                if (it is Subroutine)
-                    sub(it)
-                if (it is INameScope)
-                    findSubs(it)
-            }
-        }
-        findSubs(scope)
-    }
-
     override fun visit(program: Program) {
         super.visit(program)
 
@@ -64,15 +41,6 @@ class CallGraph(private val program: Program, private val asmFileLoader: (filena
         rootmodule.importedBy.add(rootmodule)       // don't discard root module
     }
 
-    override fun visit(block: Block) {
-        if (block.definingModule().isLibraryModule) {
-            // make sure the block is not removed
-            addNodeAndParentScopes(block)
-        }
-
-        super.visit(block)
-    }
-
     override fun visit(directive: Directive) {
         val thisModule = directive.definingModule()
         if (directive.directive == "%import") {
@@ -90,44 +58,6 @@ class CallGraph(private val program: Program, private val asmFileLoader: (filena
         super.visit(directive)
     }
 
-    override fun visit(identifier: IdentifierReference) {
-        // track symbol usage
-        val target = identifier.targetStatement(program)
-        if (target != null) {
-            addNodeAndParentScopes(target)
-        }
-        super.visit(identifier)
-    }
-
-    private fun addNodeAndParentScopes(stmt: Statement) {
-        usedSymbols.add(stmt)
-        var node: Node = stmt
-        do {
-            if (node is INameScope && node is Statement) {
-                usedSymbols.add(node)
-            }
-            node = node.parent
-        } while (node !is Module && node !is ParentSentinel)
-    }
-
-    override fun visit(subroutine: Subroutine) {
-        if (Pair(subroutine.definingScope().name, subroutine.name) in alwaysKeepSubroutines
-                || subroutine.definingModule().isLibraryModule) {
-            // make sure the entrypoint is mentioned in the used symbols
-            addNodeAndParentScopes(subroutine)
-        }
-        super.visit(subroutine)
-    }
-
-    override fun visit(decl: VarDecl) {
-        if (decl.autogeneratedDontRemove || decl.datatype==DataType.STRUCT)
-            addNodeAndParentScopes(decl)
-        else if(decl.parent is Block && decl.definingModule().isLibraryModule)
-            addNodeAndParentScopes(decl)
-
-        super.visit(decl)
-    }
-
     override fun visit(functionCall: FunctionCall) {
         val otherSub = functionCall.target.targetSubroutine(program)
         if (otherSub != null) {
@@ -172,11 +102,6 @@ class CallGraph(private val program: Program, private val asmFileLoader: (filena
         super.visit(jump)
     }
 
-    override fun visit(structDecl: StructDecl) {
-        usedSymbols.add(structDecl)
-        usedSymbols.addAll(structDecl.statements)
-    }
-
     override fun visit(inlineAssembly: InlineAssembly) {
         // parse inline asm for subroutine calls (jmp, jsr, bra)
         val scope = inlineAssembly.definingSubroutine()
@@ -274,4 +199,14 @@ class CallGraph(private val program: Program, private val asmFileLoader: (filena
         recStack[sub] = false
         return false
     }
+
+    fun unused(stmt: ISymbolStatement): Boolean {
+        if(stmt is Subroutine)
+            return calledBy[stmt].isNullOrEmpty()   // TODO also check inline assembly if it uses the subroutine
+
+        // TODO implement algorithm to check usages of other things:
+        // stmt can be: Block, Label, VarDecl (including ParameterVarDecl), Subroutine, StructDecl.
+        // NOTE also check inline assembly blocks that may reference a name.
+        return false
+    }
 }

compiler/src/prog8/optimizer/ConstantFoldingOptimizer.kt

@@ -14,7 +14,6 @@ import kotlin.math.pow
 
 
 internal class ConstantFoldingOptimizer(private val program: Program, private val compTarget: ICompilationTarget) : AstWalker() {
-    private val noModifications = emptyList<IAstModification>()
 
     override fun before(memread: DirectMemoryRead, parent: Node): Iterable<IAstModification> {
         // @( &thing )  -->  thing

compiler/src/prog8/optimizer/ConstantIdentifierReplacer.kt

@@ -15,7 +15,6 @@ import prog8.compiler.target.ICompilationTarget
 
 // Fix up the literal value's type to match that of the vardecl
 internal class VarConstantValueTypeAdjuster(private val program: Program, private val errors: IErrorReporter) : AstWalker() {
-    private val noModifications = emptyList<IAstModification>()
 
     override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
         try {
@@ -40,7 +39,6 @@ internal class VarConstantValueTypeAdjuster(private val program: Program, privat
 // and the array var initializer values and sizes.
 // This is needed because further constant optimizations depend on those.
 internal class ConstantIdentifierReplacer(private val program: Program, private val errors: IErrorReporter, private val compTarget: ICompilationTarget) : AstWalker() {
-    private val noModifications = emptyList<IAstModification>()
 
     override fun after(identifier: IdentifierReference, parent: Node): Iterable<IAstModification> {
         // replace identifiers that refer to const value, with the value itself

compiler/src/prog8/optimizer/ExpressionSimplifier.kt

@@ -25,7 +25,6 @@ import kotlin.math.pow
 internal class ExpressionSimplifier(private val program: Program) : AstWalker() {
     private val powersOfTwo = (1..16).map { (2.0).pow(it) }.toSet()
     private val negativePowersOfTwo = powersOfTwo.map { -it }.toSet()
-    private val noModifications = emptyList<IAstModification>()
 
     override fun after(typecast: TypecastExpression, parent: Node): Iterable<IAstModification> {
         val mods = mutableListOf<IAstModification>()

compiler/src/prog8/optimizer/Extensions.kt

@@ -4,7 +4,6 @@ import prog8.ast.IBuiltinFunctions
 import prog8.ast.Program
 import prog8.compiler.IErrorReporter
 import prog8.compiler.target.ICompilationTarget
-import java.nio.file.Path
 
 
 internal fun Program.constantFold(errors: IErrorReporter, compTarget: ICompilationTarget) {
@@ -43,9 +42,8 @@ internal fun Program.constantFold(errors: IErrorReporter, compTarget: ICompilati
 
 internal fun Program.optimizeStatements(errors: IErrorReporter,
                                         functions: IBuiltinFunctions,
-                                        compTarget: ICompilationTarget,
+                                        compTarget: ICompilationTarget): Int {
-                                        asmFileLoader: (filename: String, source: Path)->String): Int {
+    val optimizer = StatementOptimizer(this, errors, functions, compTarget)
-    val optimizer = StatementOptimizer(this, errors, functions, compTarget, asmFileLoader)
     optimizer.visit(this)
     val optimizationCount = optimizer.applyModifications()
 

compiler/src/prog8/optimizer/StatementOptimizer.kt

@@ -12,7 +12,6 @@ import prog8.ast.walk.IAstModification
 import prog8.ast.walk.IAstVisitor
 import prog8.compiler.IErrorReporter
 import prog8.compiler.target.ICompilationTarget
-import java.nio.file.Path
 import kotlin.math.floor
 
 internal const val retvarName = "prog8_retval"
@@ -21,29 +20,10 @@ internal const val retvarName = "prog8_retval"
 internal class StatementOptimizer(private val program: Program,
                                   private val errors: IErrorReporter,
                                   private val functions: IBuiltinFunctions,
-                                  private val compTarget: ICompilationTarget,
+                                  private val compTarget: ICompilationTarget) : AstWalker() {
-                                  asmFileLoader: (filename: String, source: Path)->String
-) : AstWalker() {
 
-    private val noModifications = emptyList<IAstModification>()
-    private val callgraph = CallGraph(program, asmFileLoader)
     private val subsThatNeedReturnVariable = mutableSetOf<Triple<INameScope, DataType, Position>>()
 
-    override fun after(block: Block, parent: Node): Iterable<IAstModification> {
-        if("force_output" !in block.options()) {
-            if (block.containsNoCodeNorVars()) {
-                if(block.name != program.internedStringsModuleName)
-                    errors.warn("removing empty block '${block.name}'", block.position)
-                return listOf(IAstModification.Remove(block, parent as INameScope))
-            }
-
-            if (block !in callgraph.usedSymbols) {
-                errors.warn("removing unused block '${block.name}'", block.position)
-                return listOf(IAstModification.Remove(block, parent as INameScope))
-            }
-        }
-        return noModifications
-    }
 
     override fun after(subroutine: Subroutine, parent: Node): Iterable<IAstModification> {
         for(returnvar in subsThatNeedReturnVariable) {
@@ -51,38 +31,6 @@ internal class StatementOptimizer(private val program: Program,
             returnvar.first.statements.add(0, decl)
         }
         subsThatNeedReturnVariable.clear()
-
-        val forceOutput = "force_output" in subroutine.definingBlock().options()
-        if(subroutine.asmAddress==null && !forceOutput) {
-            if(subroutine.containsNoCodeNorVars() && !subroutine.inline) {
-                errors.warn("removing empty subroutine '${subroutine.name}'", subroutine.position)
-                val removals = callgraph.calledBy.getValue(subroutine).map {
-                    IAstModification.Remove(it, it.definingScope())
-                }.toMutableList()
-                removals += IAstModification.Remove(subroutine, subroutine.definingScope())
-                return removals
-            }
-        }
-
-        if(subroutine !in callgraph.usedSymbols && !forceOutput) {
-            if(!subroutine.isAsmSubroutine) {
-                errors.warn("removing unused subroutine '${subroutine.name}'", subroutine.position)
-                return listOf(IAstModification.Remove(subroutine, subroutine.definingScope()))
-            }
-        }
-
-        return noModifications
-    }
-
-    override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
-        val forceOutput = "force_output" in decl.definingBlock().options()
-        if(decl !in callgraph.usedSymbols && !forceOutput) {
-            if(decl.type == VarDeclType.VAR)
-                errors.warn("removing unused variable '${decl.name}'", decl.position)
-
-            return listOf(IAstModification.Remove(decl, decl.definingScope()))
-        }
-
         return noModifications
     }
 

compiler/src/prog8/optimizer/SubroutineInliner.kt

@@ -4,8 +4,12 @@ import prog8.ast.IFunctionCall
 import prog8.ast.Node
 import prog8.ast.Program
 import prog8.ast.base.Position
-import prog8.ast.expressions.*
+import prog8.ast.expressions.FunctionCall
-import prog8.ast.statements.*
+import prog8.ast.expressions.IdentifierReference
+import prog8.ast.statements.FunctionCallStatement
+import prog8.ast.statements.Return
+import prog8.ast.statements.Subroutine
+import prog8.ast.statements.VarDecl
 import prog8.ast.walk.AstWalker
 import prog8.ast.walk.IAstModification
 import prog8.compiler.CompilationOptions
@@ -13,7 +17,6 @@ import prog8.compiler.IErrorReporter
 
 
 internal class SubroutineInliner(private val program: Program, val errors: IErrorReporter, private val compilerOptions: CompilationOptions): AstWalker() {
-    private val noModifications = emptyList<IAstModification>()
     private var callsToInlinedSubroutines = mutableListOf<Pair<IFunctionCall, Node>>()
 
     fun fixCallsToInlinedSubroutines() {

compiler/src/prog8/optimizer/UnusedCodeRemover.kt

@@ -1,8 +1,10 @@
 package prog8.optimizer
 
 import prog8.ast.INameScope
+import prog8.ast.Module
 import prog8.ast.Node
 import prog8.ast.Program
+import prog8.ast.base.VarDeclType
 import prog8.ast.expressions.BinaryExpression
 import prog8.ast.expressions.FunctionCall
 import prog8.ast.expressions.PrefixExpression
@@ -18,39 +20,17 @@ import java.nio.file.Path
 internal class UnusedCodeRemover(private val program: Program,
                                  private val errors: IErrorReporter,
                                  private val compTarget: ICompilationTarget,
-                                 private val asmFileLoader: (filename: String, source: Path)->String): AstWalker() {
+                                 asmFileLoader: (filename: String, source: Path)->String): AstWalker() {
 
-    override fun before(program: Program, parent: Node): Iterable<IAstModification> {
+    private val callgraph = CallGraph(program, asmFileLoader)
-        val callgraph = CallGraph(program, asmFileLoader)
-        val removals = mutableListOf<IAstModification>()
 
-        // remove all subroutines that aren't called, or are empty
+    override fun before(module: Module, parent: Node): Iterable<IAstModification> {
-        // NOTE: part of this is also done already in the StatementOptimizer
+        return if (!module.isLibraryModule && (module.importedBy.isEmpty() || module.containsNoCodeNorVars()))
-        val entrypoint = program.entrypoint()
+            listOf(IAstModification.Remove(module, module.definingScope()))
-        program.modules.forEach {
+        else
-            callgraph.forAllSubroutines(it) { sub ->
+            noModifications
-                val forceOutput = "force_output" in sub.definingBlock().options()
-                if (sub !== entrypoint && !forceOutput && !sub.isAsmSubroutine && (callgraph.calledBy[sub].isNullOrEmpty() || sub.containsNoCodeNorVars())) {
-                    removals.add(IAstModification.Remove(sub, sub.definingScope()))
-                }
-            }
-        }
-
-        program.modules.flatMap { it.statements }.filterIsInstance<Block>().forEach { block ->
-            if (block.containsNoCodeNorVars() && "force_output" !in block.options())
-                removals.add(IAstModification.Remove(block, block.definingScope()))
-        }
-
-        // remove modules that are not imported, or are empty (unless it's a library modules)
-        program.modules.forEach {
-            if (!it.isLibraryModule && (it.importedBy.isEmpty() || it.containsNoCodeNorVars()))
-                removals.add(IAstModification.Remove(it, it.definingScope()))
-        }
-
-        return removals
     }
 
-
     override fun before(breakStmt: Break, parent: Node): Iterable<IAstModification> {
         reportUnreachable(breakStmt, parent as INameScope)
         return emptyList()
@@ -85,15 +65,58 @@ internal class UnusedCodeRemover(private val program: Program,
     }
 
     override fun after(block: Block, parent: Node): Iterable<IAstModification> {
+        if("force_output" !in block.options()) {
+            if (block.containsNoCodeNorVars()) {
+                if(block.name != program.internedStringsModuleName)
+                    errors.warn("removing unused block '${block.name}'", block.position)
+                return listOf(IAstModification.Remove(block, parent as INameScope))
+            }
+            if(callgraph.unused(block)) {
+                errors.warn("removing unused block '${block.name}'", block.position)
+                return listOf(IAstModification.Remove(block, parent as INameScope))
+            }
+        }
+
         val removeDoubleAssignments = deduplicateAssignments(block.statements)
         return removeDoubleAssignments.map { IAstModification.Remove(it, block) }
     }
 
     override fun after(subroutine: Subroutine, parent: Node): Iterable<IAstModification> {
+        val forceOutput = "force_output" in subroutine.definingBlock().options()
+        if (subroutine !== program.entrypoint() && !forceOutput && !subroutine.inline && !subroutine.isAsmSubroutine) {
+            if(callgraph.unused(subroutine)) {
+                if(!subroutine.definingModule().isLibraryModule)
+                    errors.warn("removing unused subroutine '${subroutine.name}'", subroutine.position)
+                return listOf(IAstModification.Remove(subroutine, subroutine.definingScope()))
+            }
+            if(subroutine.containsNoCodeNorVars()) {
+                if(!subroutine.definingModule().isLibraryModule)
+                    errors.warn("removing empty subroutine '${subroutine.name}'", subroutine.position)
+                val removals = mutableListOf(IAstModification.Remove(subroutine, subroutine.definingScope()))
+                callgraph.calledBy[subroutine]?.let {
+                    for(node in it)
+                        removals.add(IAstModification.Remove(node, node.definingScope()))
+                }
+                return removals
+            }
+        }
+
         val removeDoubleAssignments = deduplicateAssignments(subroutine.statements)
         return removeDoubleAssignments.map { IAstModification.Remove(it, subroutine) }
     }
 
+    override fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> {
+        val forceOutput = "force_output" in decl.definingBlock().options()
+        if(!forceOutput && callgraph.unused(decl)) {
+            if(decl.type == VarDeclType.VAR)
+                errors.warn("removing unused variable '${decl.name}'", decl.position)
+
+            return listOf(IAstModification.Remove(decl, decl.definingScope()))
+        }
+
+        return noModifications
+    }
+
     private fun deduplicateAssignments(statements: List<Statement>): List<Assignment> {
         // removes 'duplicate' assignments that assign the same target directly after another
         val linesToRemove = mutableListOf<Assignment>()

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

@@ -7,6 +7,10 @@ import prog8.ast.walk.AstWalker
 import prog8.ast.walk.IAstVisitor
 
 
+interface ISymbolStatement {
+    val name: String
+}
+
 sealed class Statement : Node {
     abstract fun accept(visitor: IAstVisitor)
     abstract fun accept(visitor: AstWalker, parent: Node)
@@ -48,7 +52,7 @@ class Block(override val name: String,
             val address: Int?,
             override var statements: MutableList<Statement>,
             val isInLibrary: Boolean,
-            override val position: Position) : Statement(), INameScope {
+            override val position: Position) : Statement(), INameScope, ISymbolStatement {
     override lateinit var parent: Node
 
     override fun linkParents(parent: Node) {
@@ -95,7 +99,7 @@ data class DirectiveArg(val str: String?, val name: String?, val int: Int?, over
     override fun replaceChildNode(node: Node, replacement: Node) = throw FatalAstException("can't replace here")
 }
 
-data class Label(val name: String, override val position: Position) : Statement() {
+data class Label(override val name: String, override val position: Position) : Statement(), ISymbolStatement {
     override lateinit var parent: Node
 
     override fun linkParents(parent: Node) {
@@ -153,17 +157,16 @@ enum class ZeropageWish {
     NOT_IN_ZEROPAGE
 }
 
-
 open class VarDecl(val type: VarDeclType,
                    private val declaredDatatype: DataType,
                    val zeropage: ZeropageWish,
                    var arraysize: ArrayIndex?,
-                   val name: String,
+                   override val name: String,
                    private val structName: String?,
                    var value: Expression?,
                    val isArray: Boolean,
                    val autogeneratedDontRemove: Boolean,
-                   override val position: Position) : Statement() {
+                   override val position: Position) : Statement(), ISymbolStatement {
     override lateinit var parent: Node
     var struct: StructDecl? = null        // set later (because at parse time, we only know the name)
         private set
@@ -281,7 +284,6 @@ open class VarDecl(val type: VarDeclType,
 class ParameterVarDecl(name: String, declaredDatatype: DataType, position: Position)
     : VarDecl(VarDeclType.VAR, declaredDatatype, ZeropageWish.DONTCARE, null, name, null, null, false, true, position)
 
-
 class ArrayIndex(var indexExpr: Expression,
                  override val position: Position) : Node {
     override lateinit var parent: Node
@@ -484,7 +486,6 @@ data class AssignTarget(var identifier: IdentifierReference?,
     fun copy() = AssignTarget(identifier?.copy(), arrayindexed?.copy(), memoryAddress?.copy(), position)
 }
 
-
 class PostIncrDecr(var target: AssignTarget, val operator: String, override val position: Position) : Statement() {
     override lateinit var parent: Node
 
@@ -611,7 +612,6 @@ class NopStatement(override val position: Position): Statement() {
     override fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
 }
 
-
 class AsmGenInfo {
     // This class contains various attributes that influence the assembly code generator.
     // Conceptually it should be part of any INameScope.
@@ -637,7 +637,7 @@ class Subroutine(override val name: String,
                  val isAsmSubroutine: Boolean,
                  val inline: Boolean,
                  override var statements: MutableList<Statement>,
-                 override val position: Position) : Statement(), INameScope {
+                 override val position: Position) : Statement(), INameScope, ISymbolStatement {
 
     constructor(name: String, parameters: List<SubroutineParameter>, returntypes: List<DataType>, statements: MutableList<Statement>, inline: Boolean, position: Position)
             : this(name, parameters, returntypes, emptyList(), determineReturnRegisters(returntypes), emptySet(), null, false, inline, statements, position)
@@ -701,7 +701,6 @@ class Subroutine(override val name: String,
             .count { " rti" in it || "\trti" in it || " rts" in it || "\trts" in it || " jmp" in it || "\tjmp" in it || " bra" in it || "\tbra" in it}
 }
 
-
 open class SubroutineParameter(val name: String,
                                val type: DataType,
                                override val position: Position) : Node {
@@ -948,10 +947,9 @@ class WhenChoice(var values: MutableList<Expression>?,           // if null,  th
     fun accept(visitor: AstWalker, parent: Node) = visitor.visit(this, parent)
 }
 
-
 class StructDecl(override val name: String,
                  override var statements: MutableList<Statement>,      // actually, only vardecls here
-                 override val position: Position): Statement(), INameScope {
+                 override val position: Position): Statement(), INameScope, ISymbolStatement {
 
     override lateinit var parent: Node
 

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

@@ -76,86 +76,88 @@ interface IAstModification {
 
 
 abstract class AstWalker {
-    open fun before(addressOf: AddressOf, parent: Node): Iterable<IAstModification> = emptyList()
+    protected val noModifications = emptyList<IAstModification>()
-    open fun before(array: ArrayLiteralValue, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(arrayIndexedExpression: ArrayIndexedExpression, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(assignTarget: AssignTarget, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(assignment: Assignment, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(block: Block, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(branchStatement: BranchStatement, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(breakStmt: Break, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(decl: VarDecl, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(directive: Directive, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(expr: BinaryExpression, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(expr: PrefixExpression, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(forLoop: ForLoop, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(repeatLoop: RepeatLoop, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(functionCall: FunctionCall, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(functionCallStatement: FunctionCallStatement, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(identifier: IdentifierReference, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(ifStatement: IfStatement, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(inlineAssembly: InlineAssembly, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(jump: Jump, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(label: Label, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(memread: DirectMemoryRead, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(memwrite: DirectMemoryWrite, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(module: Module, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(nopStatement: NopStatement, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(numLiteral: NumericLiteralValue, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(postIncrDecr: PostIncrDecr, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(program: Program, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(range: RangeExpr, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(untilLoop: UntilLoop, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(returnStmt: Return, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(scope: AnonymousScope, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(string: StringLiteralValue, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(structDecl: StructDecl, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(subroutine: Subroutine, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(typecast: TypecastExpression, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(whenChoice: WhenChoice, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(whenStatement: WhenStatement, parent: Node): Iterable<IAstModification> = emptyList()
-    open fun before(whileLoop: WhileLoop, parent: Node): Iterable<IAstModification> = emptyList()
 
-    open fun after(addressOf: AddressOf, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(addressOf: AddressOf, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(array: ArrayLiteralValue, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(array: ArrayLiteralValue, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(arrayIndexedExpression: ArrayIndexedExpression, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(arrayIndexedExpression: ArrayIndexedExpression, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(assignTarget: AssignTarget, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(assignTarget: AssignTarget, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(assignment: Assignment, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(assignment: Assignment, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(block: Block, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(block: Block, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(branchStatement: BranchStatement, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(branchStatement: BranchStatement, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(breakStmt: Break, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(breakStmt: Break, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(builtinFunctionStatementPlaceholder: BuiltinFunctionStatementPlaceholder, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(decl: VarDecl, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(directive: Directive, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(directive: Directive, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(expr: BinaryExpression, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(expr: BinaryExpression, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(expr: PrefixExpression, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(expr: PrefixExpression, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(forLoop: ForLoop, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(forLoop: ForLoop, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(repeatLoop: RepeatLoop, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(repeatLoop: RepeatLoop, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(functionCall: FunctionCall, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(functionCall: FunctionCall, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(functionCallStatement: FunctionCallStatement, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(functionCallStatement: FunctionCallStatement, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(identifier: IdentifierReference, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(identifier: IdentifierReference, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(ifStatement: IfStatement, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(ifStatement: IfStatement, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(inlineAssembly: InlineAssembly, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(inlineAssembly: InlineAssembly, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(jump: Jump, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(jump: Jump, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(label: Label, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(label: Label, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(memread: DirectMemoryRead, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(memread: DirectMemoryRead, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(memwrite: DirectMemoryWrite, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(memwrite: DirectMemoryWrite, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(module: Module, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(module: Module, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(nopStatement: NopStatement, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(nopStatement: NopStatement, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(numLiteral: NumericLiteralValue, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(numLiteral: NumericLiteralValue, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(postIncrDecr: PostIncrDecr, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(postIncrDecr: PostIncrDecr, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(program: Program, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(program: Program, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(range: RangeExpr, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(range: RangeExpr, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(untilLoop: UntilLoop, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(untilLoop: UntilLoop, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(returnStmt: Return, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(returnStmt: Return, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(scope: AnonymousScope, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(scope: AnonymousScope, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(string: StringLiteralValue, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(string: StringLiteralValue, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(structDecl: StructDecl, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(structDecl: StructDecl, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(subroutine: Subroutine, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(subroutine: Subroutine, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(typecast: TypecastExpression, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(typecast: TypecastExpression, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(whenChoice: WhenChoice, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(whenChoice: WhenChoice, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(whenStatement: WhenStatement, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(whenStatement: WhenStatement, parent: Node): Iterable<IAstModification> = emptyList()
+    open fun before(whileLoop: WhileLoop, parent: Node): Iterable<IAstModification> = noModifications
-    open fun after(whileLoop: WhileLoop, parent: Node): Iterable<IAstModification> = emptyList()
+
+    open fun after(addressOf: AddressOf, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(array: ArrayLiteralValue, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(arrayIndexedExpression: ArrayIndexedExpression, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(assignTarget: AssignTarget, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(assignment: Assignment, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(block: Block, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(branchStatement: BranchStatement, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(breakStmt: Break, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(builtinFunctionStatementPlaceholder: BuiltinFunctionStatementPlaceholder, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(decl: VarDecl, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(directive: Directive, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(expr: BinaryExpression, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(expr: PrefixExpression, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(forLoop: ForLoop, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(repeatLoop: RepeatLoop, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(functionCall: FunctionCall, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(functionCallStatement: FunctionCallStatement, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(identifier: IdentifierReference, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(ifStatement: IfStatement, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(inlineAssembly: InlineAssembly, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(jump: Jump, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(label: Label, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(memread: DirectMemoryRead, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(memwrite: DirectMemoryWrite, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(module: Module, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(nopStatement: NopStatement, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(numLiteral: NumericLiteralValue, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(postIncrDecr: PostIncrDecr, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(program: Program, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(range: RangeExpr, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(untilLoop: UntilLoop, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(returnStmt: Return, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(scope: AnonymousScope, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(string: StringLiteralValue, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(structDecl: StructDecl, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(subroutine: Subroutine, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(typecast: TypecastExpression, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(whenChoice: WhenChoice, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(whenStatement: WhenStatement, parent: Node): Iterable<IAstModification> = noModifications
+    open fun after(whileLoop: WhileLoop, parent: Node): Iterable<IAstModification> = noModifications
 
     protected val modifications = mutableListOf<Triple<IAstModification, Node, Node>>()
     // private val modificationsReplacedNodes = mutableSetOf<Pair<Node, Position>>()

docs/source/syntaxreference.rst

@@ -129,7 +129,7 @@ Directives
       take care of that yourself. The program will just start running from whatever state the machine is in when the
       program was launched.
     - ``force_output`` (in a block) will force the block to be outputted in the final program.
-      Can be useful to make sure some data is generated that would otherwise be discarded because it's not referenced (such as sprite data).
+      Can be useful to make sure some data is generated that would otherwise be discarded because the compiler thinks it's not referenced (such as sprite data)
     - ``align_word`` (in a block) will make the assembler align the start address of this block on a word boundary in memory (so, an even memory address).
     - ``align_page`` (in a block) will make the assembler align the start address of this block on a page boundary in memory (so, the LSB of the address is 0).
 

docs/source/todo.rst

@@ -2,6 +2,10 @@
 TODO
 ====
 
+- fix crash parent node mismatch with -noopt (textelite)
+
+- implement new 'unused' in CallGraph for more node types
+
 - allow inlining of subroutines with params
 - optimize several inner loops in gfx2
 - hoist all variable declarations up to the subroutine scope *before* even the constant folding takes place (to avoid undefined symbol errors when referring to a variable from another nested scope in the subroutine)

examples/test.p8

@@ -1,4 +1,3 @@
-%import textio
 %zeropage basicsafe
 
 main {
@@ -9,6 +8,26 @@ main {
 ; Comment here
                            4,5,6 ]
 
-        txt.print_ub(len(array))
+        ubyte zz = len(array)
+
+        ubyte foobar
+        empty2()
+
+        %asm {{
+            lda  foobar
+        }}
+    }
+
+    sub nix() {
+    }
+
+    sub empty2() {
+    }
+}
+
+derp {
+    sub nix2() {
+        ubyte zz
+        zz++
     }
 }