optimizer: avoid symbol name clash when inlining subroutine

codeOptimizers/src/prog8/optimizer/Extensions.kt

@@ -54,8 +54,8 @@ fun Program.optimizeStatements(errors: IErrorReporter,
     return optimizationCount
 }
 
-fun Program.inlineSubroutines(): Int {
-    val inliner = Inliner(this)
+fun Program.inlineSubroutines(options: CompilationOptions): Int {
+    val inliner = Inliner(this, options)
     inliner.visit(this)
     return inliner.applyModifications()
 }

codeOptimizers/src/prog8/optimizer/Inliner.kt

@@ -8,7 +8,9 @@ import prog8.ast.statements.*
 import prog8.ast.walk.AstWalker
 import prog8.ast.walk.IAstModification
 import prog8.ast.walk.IAstVisitor
+import prog8.code.core.CompilationOptions
 import prog8.code.core.InternalCompilerException
+import prog8.code.target.VMTarget
 
 
 private  fun isEmptyReturn(stmt: Statement): Boolean = stmt is Return && stmt.value==null
@@ -16,7 +18,7 @@ private  fun isEmptyReturn(stmt: Statement): Boolean = stmt is Return && stmt.va
 
 // inliner potentially enables *ONE LINED* subroutines, wihtout to be inlined.
 
-class Inliner(val program: Program): AstWalker() {
+class Inliner(private val program: Program, private val options: CompilationOptions): AstWalker() {
 
     class DetermineInlineSubs(val program: Program): IAstVisitor {
         private val modifications = mutableListOf<IAstModification>()
@@ -211,7 +213,7 @@ class Inliner(val program: Program): AstWalker() {
 
     override fun after(functionCallStatement: FunctionCallStatement, parent: Node): Iterable<IAstModification>  {
         val sub = functionCallStatement.target.targetStatement(program) as? Subroutine
-        return if(sub==null)
+        return if(sub==null || !canInline(sub, functionCallStatement))
             noModifications
         else
             possibleInlineFcallStmt(sub, functionCallStatement, parent)
@@ -219,7 +221,7 @@ class Inliner(val program: Program): AstWalker() {
 
     override fun before(functionCallExpr: FunctionCallExpression, parent: Node): Iterable<IAstModification> {
         val sub = functionCallExpr.target.targetStatement(program) as? Subroutine
-        if(sub!=null && sub.inline && sub.parameters.isEmpty()) {
+        if(sub!=null && sub.inline && sub.parameters.isEmpty() && canInline(sub, functionCallExpr)) {
             require(sub.statements.size == 1 || (sub.statements.size == 2 && isEmptyReturn(sub.statements[1]))) {
                 "invalid inline sub at ${sub.position}"
             }
@@ -246,5 +248,17 @@ class Inliner(val program: Program): AstWalker() {
         return noModifications
     }
 
+    private fun canInline(sub: Subroutine, fcall: IFunctionCall): Boolean {
+        if(!sub.inline)
+            return false
+        if(options.compTarget.name!=VMTarget.NAME) {
+            val stmt = sub.statements.single()
+            if (stmt is IFunctionCall) {
+                val existing = (fcall as Node).definingScope.lookup(stmt.target.nameInSource.take(1))
+                return existing !is VarDecl
+            }
+        }
+        return true
+    }
 }
 

compiler/src/prog8/compiler/Compiler.kt

@@ -369,7 +369,7 @@ private fun optimizeAst(program: Program, compilerOptions: CompilationOptions, e
         val optsDone1 = program.simplifyExpressions(errors, compTarget)
         val optsDone2 = program.splitBinaryExpressions(compilerOptions)
         val optsDone3 = program.optimizeStatements(errors, functions, compilerOptions)
-        val optsDone4 = program.inlineSubroutines()
+        val optsDone4 = program.inlineSubroutines(compilerOptions)
         program.constantFold(errors, compTarget) // because simplified statements and expressions can result in more constants that can be folded away
         errors.report()
         if (optsDone1 + optsDone2 + optsDone3 + optsDone4 == 0)

compiler/test/codegeneration/TestVariousCodeGen.kt

@@ -257,4 +257,31 @@ mylabel:
 """
         compileText(Cx16Target(), true, src, writeAssembly = true) shouldNotBe null
     }
+
+    test("duplicate symbols okay other block and variable") {
+        val src = """
+main {
+    ubyte derp
+    sub start() {
+        derp++
+        foo.bar()
+    }
+}
+
+foo {
+    sub bar() {
+        derp.print()
+    }
+}
+
+derp {
+    sub print() {
+        cx16.r0++
+        cx16.r1++
+    }
+}"""
+
+        compileText(VMTarget(), true, src, writeAssembly = true) shouldNotBe null
+        compileText(Cx16Target(), true, src, writeAssembly = true) shouldNotBe null
+    }
 })

docs/source/todo.rst

@@ -1,9 +1,6 @@
 TODO
 ====
 
-- check for name clash: variable vs block name
-
-
 ...