optimization for subs

il65/codegen.py

@@ -239,7 +239,7 @@ class CodeGenerator:
                 self.p("; end external subroutines")
             for stmt in block.statements:
                 self.generate_statement(stmt)
-            subroutines = list(sub for sub in block.symbols.iter_subroutines() if sub.address is None)
+            subroutines = list(sub for sub in block.symbols.iter_subroutines(True))
             if subroutines:
                 self.p("\n; block subroutines")
                 for subdef in subroutines:
@@ -532,8 +532,6 @@ class CodeGenerator:
                     self.p("\t\tjsr  " + targetstr)
 
     def generate_assignment(self, stmt: ParseResult.AssignmentStmt) -> None:
-        rvalue = stmt.right
-
         def unwrap_indirect(iv: ParseResult.IndirectValue) -> ParseResult.MemMappedValue:
             if isinstance(iv.value, ParseResult.MemMappedValue):
                 return iv.value
@@ -542,6 +540,7 @@ class CodeGenerator:
             else:
                 raise CodeError("cannot yet generate code for assignment: non-constant and non-memmapped indirect")  # XXX
 
+        rvalue = stmt.right
         if isinstance(rvalue, ParseResult.IndirectValue):
             rvalue = unwrap_indirect(rvalue)
         self.p("\t\t\t\t\t; src l. {:d}".format(stmt.lineno))

il65/parse.py

@@ -379,13 +379,16 @@ class ParseResult:
                 self.right.name = stringvar_name
                 self._immediate_string_vars[self.right.value] = (cur_block.name, stringvar_name)
 
-        def remove_identity_assigns(self) -> None:
+        def remove_identity_lvalues(self, filename: str, lineno: int) -> None:
             for lv in self.leftvalues:
                 if lv == self.right:
-                    print("warning: {:d}: removed identity assignment".format(self.lineno))
+                    print("{:s}:{:d}: removed identity assignment".format(filename, lineno))
             remaining_leftvalues = [lv for lv in self.leftvalues if lv != self.right]
             self.leftvalues = remaining_leftvalues
 
+        def is_identity(self) -> bool:
+            return all(lv == self.right for lv in self.leftvalues)
+
     class ReturnStmt(_AstNode):
         def __init__(self, a: Optional['ParseResult.Value']=None,
                      x: Optional['ParseResult.Value']=None,
@@ -417,8 +420,9 @@ class ParseResult:
                 for name, value in self.arguments:
                     assert name is not None, "all call arguments should have a name or be matched on a named parameter"
                     assignment = parser.parse_assignment("{:s}={:s}".format(name, value))
-                    assignment.lineno = self.lineno
-                    self.desugared_call_arguments.append(assignment)
+                    if not assignment.is_identity():
+                        assignment.lineno = self.lineno
+                        self.desugared_call_arguments.append(assignment)
 
     class InlineAsm(_AstNode):
         def __init__(self, lineno: int, asmlines: List[str]) -> None:
@@ -453,7 +457,7 @@ class Parser:
             self.lines = self.load_source(filename)
         self.outputdir = outputdir
         self.parsing_import = parsing_import     # are we parsing a import file?
-        self.cur_lineidx = -1
+        self._cur_lineidx = -1      # used to efficiently go to next/previous line in source
         self.cur_block = None  # type: ParseResult.Block
         self.root_scope = SymbolTable("<root>", None, None)
         self.ppsymbols = ppsymbols  # symboltable from preprocess phase
@@ -536,50 +540,62 @@ class Parser:
             raise self.PError("invalid statement or characters, block expected")
         if not self.parsing_import:
             # check if we have a proper main block to contain the program's entry point
+            main_found = False
             for block in self.result.blocks:
                 if block.name == "main":
+                    main_found = True
                     if "start" not in block.label_names:
                         self.sourceref.line = block.sourceref.line
                         self.sourceref.column = 0
                         raise self.PError("The 'main' block should contain the program entry point 'start'")
-                    if not any(s for s in block.statements if isinstance(s, ParseResult.ReturnStmt)):
-                        self.print_warning("warning: {}: The 'main' block is lacking a return statement.".format(block.sourceref))
-                    break
-            else:
+                    self._check_return_statement(block, "'main' block")
+                for sub in block.symbols.iter_subroutines(True):
+                    self._check_return_statement(sub.sub_block, "'{:s}' subroutine".format(sub.name))
+            if not main_found:
                 raise self.PError("A block named 'main' should be defined for the program's entry point 'start'")
 
+    def _check_return_statement(self, block: ParseResult.Block, message: str) -> None:
+        # find last statement that isn't a comment
+        for stmt in reversed(block.statements):
+            if isinstance(stmt, ParseResult.Comment):
+                continue
+            if isinstance(stmt, ParseResult.ReturnStmt) or isinstance(stmt, ParseResult.CallStmt) and stmt.is_goto:
+                return
+            if isinstance(stmt, ParseResult.InlineAsm):
+                # check that the last asm line is a jmp or a rts
+                for asmline in reversed(stmt.asmlines):
+                    if asmline.lstrip().startswith(';'):
+                        continue
+                    if " rts" in asmline or "\trts" in asmline or " jmp" in asmline or "\tjmp" in asmline:
+                        return
+                    if asmline.strip():
+                        if asmline.split()[0].isidentifier():
+                            continue
+                    break
+            break
+        self.print_warning("warning: {}: The {:s} doesn't end with a return statement".format(block.sourceref, message))
+
     def _parse_2(self) -> None:
         # parsing pass 2 (not done during preprocessing!)
         self.cur_block = None
         self.sourceref.line = -1
         self.sourceref.column = 0
+
         for block in self.result.blocks:
             self.cur_block = block
-            # remove identity assignments
-            have_removed_stmts = False
-            for index, stmt in enumerate(list(block.statements)):
-                if isinstance(stmt, ParseResult.AssignmentStmt):
-                    stmt.remove_identity_assigns()
-                    if not stmt.leftvalues:
-                        print("warning: {:s}:{:d}: removed identity assignment statement".format(self.sourceref.file, stmt.lineno))
-                        have_removed_stmts = True
-                        block.statements[index] = None
-            if have_removed_stmts:
-                # remove the Nones
-                block.statements = [s for s in block.statements if s is not None]
             # create parameter loads for calls
             for index, stmt in enumerate(list(block.statements)):
                 if isinstance(stmt, ParseResult.CallStmt):
                     self.sourceref.line = stmt.lineno
                     self.sourceref.column = 0
                     stmt.desugar_call_arguments(self)
-            for sub in block.symbols.iter_subroutines():
-                if sub.address is None and sub.sub_block:
-                    for stmt in sub.sub_block.statements:
-                        if isinstance(stmt, ParseResult.CallStmt):
-                            self.sourceref.line = stmt.lineno
-                            self.sourceref.column = 0
-                            stmt.desugar_call_arguments(self)
+            # create parameter loads for calls, in subroutine blocks
+            for sub in block.symbols.iter_subroutines(True):
+                for stmt in sub.sub_block.statements:
+                    if isinstance(stmt, ParseResult.CallStmt):
+                        self.sourceref.line = stmt.lineno
+                        self.sourceref.column = 0
+                        stmt.desugar_call_arguments(self)
             block.flatten_statement_list()
             # desugar immediate string value assignments
             for index, stmt in enumerate(list(block.statements)):
@@ -594,38 +610,32 @@ class Parser:
                     stmt.desugar_immediate_string(self)
 
     def next_line(self) -> str:
-        self.cur_lineidx += 1
+        self._cur_lineidx += 1
         try:
-            self.sourceref.line, line = self.lines[self.cur_lineidx]
+            self.sourceref.line, line = self.lines[self._cur_lineidx]
             self.sourceref.column = 0
             return line
         except IndexError:
             return ""
 
     def prev_line(self) -> str:
-        self.cur_lineidx -= 1
-        self.sourceref.line, line = self.lines[self.cur_lineidx]
+        self._cur_lineidx -= 1
+        self.sourceref.line, line = self.lines[self._cur_lineidx]
         return line
 
     def peek_next_line(self) -> str:
-        if (self.cur_lineidx + 1) < len(self.lines):
-            return self.lines[self.cur_lineidx + 1][1]
+        if (self._cur_lineidx + 1) < len(self.lines):
+            return self.lines[self._cur_lineidx + 1][1]
         return ""
 
     def PError(self, message: str, lineno: int=0, column: int=0) -> ParseError:
         sourceline = ""
-        if lineno:
-            for num, text in self.lines:
-                if num == lineno:
-                    sourceline = text.strip()
-                    break
-        else:
-            lineno = self.sourceref.line
-            column = self.sourceref.column
-            self.cur_lineidx = min(self.cur_lineidx, len(self.lines) - 1)
-            if self.cur_lineidx:
-                sourceline = self.lines[self.cur_lineidx][1].strip()
-        # XXX source line is wrong when dealing with errors in sub call
+        lineno = lineno or self.sourceref.line
+        column = column or self.sourceref.column
+        for num, text in self.lines:
+            if num == lineno:
+                sourceline = text.strip()
+                break
         return ParseError(message, sourceline, SourceRef(self.sourceref.file, lineno, column))
 
     def get_datatype(self, typestr: str) -> Tuple[DataType, int, Optional[Tuple[int, int]]]:
@@ -1377,8 +1387,13 @@ class Optimizer:
     def optimize(self) -> ParseResult:
         print("\noptimizing parse tree")
         for block in self.parsed.blocks:
+            self.remove_identity_assigns(block)
             self.combine_assignments_into_multi(block)
             self.optimize_multiassigns(block)
+            for sub in block.symbols.iter_subroutines(True):
+                self.remove_identity_assigns(sub.sub_block)
+                self.combine_assignments_into_multi(sub.sub_block)
+                self.optimize_multiassigns(sub.sub_block)
         return self.parsed
 
     def combine_assignments_into_multi(self, block: ParseResult.Block) -> None:
@@ -1414,6 +1429,19 @@ class Optimizer:
                 # change order: first registers, then zp addresses, then non-zp addresses, then the rest (if any)
                 stmt.leftvalues = list(sorted(lvalues, key=_value_sortkey))
 
+    def remove_identity_assigns(self, block: ParseResult.Block) -> None:
+        have_removed_stmts = False
+        for index, stmt in enumerate(list(block.statements)):
+            if isinstance(stmt, ParseResult.AssignmentStmt):
+                stmt.remove_identity_lvalues(block.sourceref.file, stmt.lineno)
+                if not stmt.leftvalues:
+                    print("{:s}:{:d}: removed identity assignment statement".format(block.sourceref.file, stmt.lineno))
+                    have_removed_stmts = True
+                    block.statements[index] = None
+        if have_removed_stmts:
+            # remove the Nones
+            block.statements = [s for s in block.statements if s is not None]
+
 
 def _value_sortkey(value: ParseResult.Value) -> int:
     if isinstance(value, ParseResult.RegisterValue):

il65/symbols.py

@@ -303,8 +303,12 @@ class SymbolTable:
     def iter_constants(self) -> Iterable[ConstantDef]:
         yield from sorted((v for v in self.symbols.values() if isinstance(v, ConstantDef)))
 
-    def iter_subroutines(self) -> Iterable[SubroutineDef]:
-        yield from sorted((v for v in self.symbols.values() if isinstance(v, SubroutineDef)))
+    def iter_subroutines(self, userdefined_only: bool=False) -> Iterable[SubroutineDef]:
+        if userdefined_only:
+            yield from sorted((sub for sub in self.symbols.values()
+                               if isinstance(sub, SubroutineDef) and sub.address is None and sub.sub_block is not None))
+        else:
+            yield from sorted((sub for sub in self.symbols.values() if isinstance(sub, SubroutineDef)))
 
     def iter_labels(self) -> Iterable[LabelDef]:
         yield from sorted((v for v in self.symbols.values() if isinstance(v, LabelDef)))