added warnshadow cli option to enable assembler warnings about symbol shadowing

codeCore/src/prog8/code/core/CompilationOptions.kt

@@ -13,6 +13,7 @@ class CompilationOptions(val output: OutputType,
                          val compTarget: ICompilationTarget,
                          // these are set later, based on command line arguments or options in the source code:
                          var loadAddress: UInt,
+                         var warnSymbolShadowing: Boolean = false,
                          var optimize: Boolean = false,
                          var asmQuiet: Boolean = false,
                          var asmListfile: Boolean = false,

codeGenCpu6502/src/prog8/codegen/cpu6502/AssemblyProgram.kt

@@ -31,6 +31,11 @@ internal class AssemblyProgram(
                     "--dump-labels", "--vice-labels", "--labels=$viceMonListFile", "--no-monitor"
                 )
 
+                if(options.warnSymbolShadowing)
+                    command.add("-Wshadow")
+                else
+                    command.add("-Wno-shadow")
+
                 if(options.asmQuiet)
                     command.add("--quiet")
 
@@ -59,10 +64,15 @@ internal class AssemblyProgram(
 
                 // TODO are these options okay for atari?
                 val command = mutableListOf("64tass", "--ascii", "--case-sensitive", "--long-branch",
-                    "-Wall", "-Wno-strict-bool", "-Wno-shadow", // "-Werror",
+                    "-Wall", // "-Werror", "-Wno-strict-bool"
                     "--no-monitor"
                 )
 
+                if(options.warnSymbolShadowing)
+                    command.add("-Wshadow")
+                else
+                    command.add("-Wno-shadow")
+
                 if(options.asmQuiet)
                     command.add("--quiet")
 

compiler/src/prog8/CompilerMain.kt

@@ -45,6 +45,7 @@ private fun compileMain(args: Array<String>): Boolean {
     val dontOptimize by cli.option(ArgType.Boolean, fullName = "noopt", description = "don't perform any optimizations")
     val outputDir by cli.option(ArgType.String, fullName = "out", description = "directory for output files instead of current directory").default(".")
     val quietAssembler by cli.option(ArgType.Boolean, fullName = "quietasm", description = "don't print assembler output results")
+    val warnSymbolShadowing by cli.option(ArgType.Boolean, fullName = "warnshadow", description="show assembler warnings about symbol shadowing")
     val sourceDirs by cli.option(ArgType.String, fullName="srcdirs", description = "list of extra paths, separated with ${File.pathSeparator}, to search in for imported modules").multiple().delimiter(File.pathSeparator)
     val includeSourcelines by cli.option(ArgType.Boolean, fullName = "sourcelines", description = "include original Prog8 source lines in generated asm code")
     val splitWordArrays by cli.option(ArgType.Boolean, fullName = "splitarrays", description = "treat all word arrays as tagged with @split to make them lsb/msb split in memory")
@@ -113,6 +114,7 @@ private fun compileMain(args: Array<String>): Boolean {
                     filepath,
                     dontOptimize != true,
                     dontWriteAssembly != true,
+                    warnSymbolShadowing == true,
                     quietAssembler == true,
                     asmListfile == true,
                     includeSourcelines == true,
@@ -180,6 +182,7 @@ private fun compileMain(args: Array<String>): Boolean {
                     filepath,
                     dontOptimize != true,
                     dontWriteAssembly != true,
+                    warnSymbolShadowing == true,
                     quietAssembler == true,
                     asmListfile == true,
                     includeSourcelines == true,

compiler/src/prog8/compiler/Compiler.kt

@@ -30,6 +30,7 @@ class CompilationResult(val compilerAst: Program,   // deprecated, use codegenAs
 class CompilerArguments(val filepath: Path,
                         val optimize: Boolean,
                         val writeAssembly: Boolean,
+                        val warnSymbolShadowing: Boolean,
                         val quietAssembler: Boolean,
                         val asmListfile: Boolean,
                         val includeSourcelines: Boolean,
@@ -67,6 +68,7 @@ fun compileProgram(args: CompilerArguments): CompilationResult? {
             compilationOptions = options
 
             with(compilationOptions) {
+                warnSymbolShadowing = args.warnSymbolShadowing
                 optimize = args.optimize
                 asmQuiet = args.quietAssembler
                 asmListfile = args.asmListfile

compiler/test/TestCompilerOnExamples.kt

@@ -27,6 +27,7 @@ private fun compileTheThing(filepath: Path, optimize: Boolean, target: ICompilat
         filepath,
         optimize,
         writeAssembly = true,
+        warnSymbolShadowing = false,
         quietAssembler = true,
         asmListfile = false,
         includeSourcelines = false,

compiler/test/TestCompilerOptionLibdirs.kt

@@ -44,6 +44,7 @@ class TestCompilerOptionSourcedirs: FunSpec({
             filepath = filePath,
             optimize = false,
             writeAssembly = true,
+            warnSymbolShadowing = false,
             quietAssembler = true,
             asmListfile = false,
             includeSourcelines = false,

compiler/test/helpers/compileXyz.kt

@@ -24,6 +24,7 @@ internal fun compileFile(
         filepath,
         optimize,
         writeAssembly = writeAssembly,
+        warnSymbolShadowing = false,
         quietAssembler = true,
         asmListfile = false,
         includeSourcelines = false,

docs/source/compiling.rst

@@ -151,6 +151,15 @@ One or more .p8 module files
     Note that it is possible to use the watch mode with multiple modules as well, but it will
     recompile everything in that list even if only one of the files got updated.
 
+``-warnshadow``
+    Tells the assembler to issue warning messages about symbol shadowing.
+    These *can* be problematic, but usually aren't because prog8 has different scoping rules
+    than the assembler has.
+    You may want to watch out for shadowing of builtin names though. Especially 'a', 'x' and 'y'
+    as those are the cpu register names and if you shadow those, the assembler might
+    interpret certain instructions differently and produce unexpected opcodes (like LDA X getting
+    turned into TXA, or not, depending on the symbol 'x' being defined in your own assembly code or not)
+
 ``-quietasm``
     Don't print assembler output results.
 

docs/source/todo.rst

@@ -1,10 +1,12 @@
 TODO
 ====
 
+- [on branch: shadowing-fixes] add shadowing warning to asm and fix shadowing errors
+- prefix prog8 subroutines with p8s_ instead of p8_ to not let them clash with variables in the asm
+
 - allow 'chained' array indexing for expressions:  value = ptrarray[0][0]
 - allow 'chained' array indexing for assign targets:  ptrarray[0][0] = 42   this is just evaluating the lhs as a uword pointer expression
 - [on branch: shortcircuit] investigate McCarthy evaluation again? this may also reduce code size perhaps for things like if a>4 or a<2 ....
-- [on branch: shadowing-fixes] add shadowing warning to asm and fix shadowing errors
 - IR: reduce the number of branch instructions such as BEQ, BEQR, etc (gradually), replace with CMP(I) + status branch instruction
 - IR: reduce amount of CMP/CMPI after instructions that set the status bits correctly (LOADs? INC? etc), but only after setting the status bits is verified!
 

examples/test.p8

@@ -1,11 +1,13 @@
 %import textio
-%import string
-%import floats
 %zeropage basicsafe
 
 main {
     sub start() {
-        float fl = floats.parse_f("-123.45678e20")
+        thing()
-        floats.print_f(fl)
+    }
+    sub thing() {
+        ubyte start=22
+        txt.print_ub(start)
+        txt.print_uw(&main.start)
     }
 }

httpCompilerService/src/prog8/http/TestHttp.kt

@@ -34,6 +34,7 @@ class RequestParser : Take {
             Path(a),
             optimize = true,
             writeAssembly = true,
+            warnSymbolShadowing = false,
             compilationTarget = "c64",
             symbolDefs = emptyMap(),
             quietAssembler = false,