Small code cleanup: combine related things (#318)

compare_compilers.sh

@@ -97,7 +97,7 @@ for action in tokenize parse run; do
         # The file is skipped, so the two compilers should behave differently
         if diff tmp/compare_compilers/compiler_written_in_c.txt tmp/compare_compilers/self_hosted.txt >/dev/null; then
             if [ $fix = yes ]; then
-                delete_line $error_list_file $file
+                remove_line $error_list_file $file
             else
                 echo "  Error: Compilers behave the same even though the file is listed in $error_list_file."
                 echo "  To fix this error, delete the \"$file\" line from $error_list_file (or run again with --fix)."

self_hosted/ast.jou

@@ -275,8 +275,7 @@ class AstCall:
 
 enum AstStatementKind:
     ExpressionStatement  # Evaluate an expression. Discard the result.
-    ReturnWithValue
-    ReturnWithoutValue
+    Return
     If
     WhileLoop
     ForLoop
@@ -299,7 +298,7 @@ class AstStatement:
     if_statement: AstIfStatement
     while_loop: AstConditionAndBody
     for_loop: AstForLoop
-    return_value: AstExpression     # AstStatementKind::ReturnWithValue
+    return_value: AstExpression*     # AstStatementKind::Return (can be NULL)
     assignment: AstAssignment
     var_declaration: AstNameTypeValue  # AstStatementKind::DeclareLocalVar
 
@@ -308,11 +307,10 @@ class AstStatement:
         if self->kind == AstStatementKind::ExpressionStatement:
             printf("expression statement\n")
             self->expression.print(tp.print_prefix(True))
-        elif self->kind == AstStatementKind::ReturnWithValue:
-            printf("return a value\n")
-            self->return_value.print(tp.print_prefix(True))
-        elif self->kind == AstStatementKind::ReturnWithoutValue:
-            printf("return without a value\n")
+        elif self->kind == AstStatementKind::Return:
+            printf("return\n")
+            if self->return_value != NULL:
+                self->return_value->print(tp.print_prefix(True))
         elif self->kind == AstStatementKind::If:
             printf("if\n")
             self->if_statement.print(tp)
@@ -353,8 +351,9 @@ class AstStatement:
     def free(self) -> void:
         if self->kind == AstStatementKind::ExpressionStatement:
             self->expression.free()
-        if self->kind == AstStatementKind::ReturnWithValue:
-            self->return_value.free()
+        if self->kind == AstStatementKind::Return and self->return_value != NULL:
+            self->return_value->free()
+            free(self->return_value)
         if self->kind == AstStatementKind::If:
             self->if_statement.free()
         if self->kind == AstStatementKind::ForLoop:
@@ -516,16 +515,14 @@ class AstImport:
 
 enum AstToplevelStatementKind:
     Import
-    FunctionDeclaration
-    FunctionDefinition
+    Function
     ClassDefinition
     GlobalVariableDeclaration
 
 class AstToplevelStatement:
     # TODO: union
     the_import: AstImport   # must be first
-    decl_signature: AstSignature
-    funcdef: AstFunctionDef
+    function: AstFunction
     classdef: AstClassDef
     global_var: AstNameTypeValue
 
@@ -540,12 +537,12 @@ class AstToplevelStatement:
                 self->the_import.specified_path,
                 self->the_import.resolved_path,
             )
-        elif self->kind == AstToplevelStatementKind::FunctionDeclaration:
-            printf("Declare a function: ")
-            self->decl_signature.print()
-        elif self->kind == AstToplevelStatementKind::FunctionDefinition:
-            printf("Define a function: ")
-            self->funcdef.print()
+        elif self->kind == AstToplevelStatementKind::Function:
+            if self->function.body.nstatements == 0:
+                printf("Declare a function: ")
+            else:
+                printf("Define a function: ")
+            self->function.print()
         elif self->kind == AstToplevelStatementKind::ClassDefinition:
             printf("Define a ")
             self->classdef.print()
@@ -596,9 +593,9 @@ class AstFile:
             self->body[i].free()
         free(self->body)
 
-class AstFunctionDef:
+class AstFunction:
     signature: AstSignature
-    body: AstBody
+    body: AstBody  # empty body means declaration, otherwise it's a definition
 
     def print(self) -> void:
         self->signature.print()
@@ -613,7 +610,7 @@ class AstClassDef:
     name_location: Location
     fields: AstNameTypeValue*
     nfields: int
-    methods: AstFunctionDef*
+    methods: AstFunction*
     nmethods: int
 
     def print(self) -> void:

self_hosted/create_llvm_ir.jou

@@ -84,9 +84,12 @@ class AstToIR:
     def do_statement(self, ast: AstStatement*) -> void:
         if ast->kind == AstStatementKind::ExpressionStatement:
             self->do_expression(&ast->expression)
-        elif ast->kind == AstStatementKind::ReturnWithValue:
-            return_value = self->do_expression(&ast->return_value)
-            LLVMBuildRet(self->builder, return_value)
+        elif ast->kind == AstStatementKind::Return:
+            if ast->return_value != NULL:
+                return_value = self->do_expression(ast->return_value)
+                LLVMBuildRet(self->builder, return_value)
+            else:
+                LLVMBuildRetVoid(self->builder)
             # If more code follows, place it into a new block that never actually runs
             self->new_block("after_return")
         else:
@@ -98,14 +101,17 @@ class AstToIR:
             self->do_statement(&body->statements[i])
 
     # The function must already be declared.
-    def define_function(self, funcdef: AstFunctionDef*) -> void:
+    def define_function(self, funcdef: AstFunction*) -> void:
         llvm_func = LLVMGetNamedFunction(self->module, &funcdef->signature.name[0])
         assert(llvm_func != NULL)
         assert(self->current_function == NULL)
         self->current_function = llvm_func
+
         self->new_block("start")
+        assert(funcdef->body.nstatements > 0)  # it is a definition
         self->do_body(&funcdef->body)
         LLVMBuildUnreachable(self->builder)
+
         self->current_function = NULL
 
 
@@ -124,8 +130,8 @@ def create_llvm_ir(ast: AstFile*, typectx: TypeContext*) -> LLVMModule*:
         a2i.declare_function(&typectx->functions[i])
 
     for i = 0; i < ast->body_len; i++:
-        if ast->body[i].kind == AstToplevelStatementKind::FunctionDefinition:
-            a2i.define_function(&ast->body[i].funcdef)
+        if ast->body[i].kind == AstToplevelStatementKind::Function and ast->body[i].function.body.nstatements > 0:
+            a2i.define_function(&ast->body[i].function)
 
     LLVMDisposeBuilder(a2i.builder)
     return module

self_hosted/parser.jou

@@ -413,11 +413,10 @@ def parse_oneline_statement(tokens: Token**) -> AstStatement:
     result = AstStatement{ location = (*tokens)->location }
     if (*tokens)->is_keyword("return"):
         ++*tokens
-        if (*tokens)->kind == TokenKind::Newline:
-            result.kind = AstStatementKind::ReturnWithoutValue
-        else:
-            result.kind = AstStatementKind::ReturnWithValue
-            result.return_value = parse_expression(tokens)
+        result.kind = AstStatementKind::Return
+        if (*tokens)->kind != TokenKind::Newline:
+            result.return_value = malloc(sizeof *result.return_value)
+            *result.return_value = parse_expression(tokens)
     elif (*tokens)->is_keyword("break"):
         ++*tokens
         result.kind = AstStatementKind::Break
@@ -554,8 +553,8 @@ def parse_body(tokens: Token**) -> AstBody:
 
     return AstBody{ statements = result, nstatements = n }
 
-def parse_funcdef(tokens: Token**) -> AstFunctionDef:
-    return AstFunctionDef{
+def parse_funcdef(tokens: Token**) -> AstFunction:
+    return AstFunction{
         signature = parse_function_signature(tokens),
         body = parse_body(tokens),
     }
@@ -594,8 +593,8 @@ def parse_toplevel_node(dest: AstFile*, tokens: Token**, stdlib_path: byte*) ->
 
     elif (*tokens)->is_keyword("def"):
         ++*tokens
-        ts.kind = AstToplevelStatementKind::FunctionDefinition
-        ts.funcdef = parse_funcdef(tokens)
+        ts.kind = AstToplevelStatementKind::Function
+        ts.function = parse_funcdef(tokens)
 
     elif (*tokens)->is_keyword("declare"):
         ++*tokens
@@ -609,8 +608,8 @@ def parse_toplevel_node(dest: AstFile*, tokens: Token**, stdlib_path: byte*) ->
                     "a value cannot be given when declaring a global variable",
                 )
         else:
-            ts.kind = AstToplevelStatementKind::FunctionDeclaration
-            ts.decl_signature = parse_function_signature(tokens)
+            ts.kind = AstToplevelStatementKind::Function
+            ts.function.signature = parse_function_signature(tokens)
         eat_newline(tokens)
 
     elif (*tokens)->is_keyword("class"):

self_hosted/runs_wrong.txt

@@ -108,7 +108,6 @@ tests/syntax_error/multidot_float.jou
 tests/syntax_error/self_outside_class.jou
 tests/syntax_error/triple_equals.jou
 tests/too_long/name.jou
-tests/wrong_type/arg.jou
 tests/wrong_type/array_mixed_types.jou
 tests/wrong_type/array_mixed_types_ptr.jou
 tests/wrong_type/array_to_ptr.jou

self_hosted/typecheck.jou

@@ -130,24 +130,16 @@ def typecheck_stage2_signatures_globals_structbodies(ctx: TypeContext*, ast_file
 
     for i = 0; i < ast_file->body_len; i++:
         ts = &ast_file->body[i]
-        # TODO: get rid of declare/define copy pasta
-        if ts->kind == AstToplevelStatementKind::FunctionDeclaration:
+        if ts->kind == AstToplevelStatementKind::Function:
             # TODO: terrible hack: skip functions that use FILE, such as fopen()
             # Will be no longer needed once struct FILE works.
-            if ts->decl_signature.name[0] == 'f' or strcmp(&ts->decl_signature.name[0], "rewind") == 0:
+            if ts->function.body.nstatements == 0 and (
+                ts->function.signature.name[0] == 'f'
+                or strcmp(&ts->function.signature.name[0], "rewind") == 0
+            ):
                 continue
 
-            sig = handle_signature(ctx, &ts->decl_signature)
-            ctx->functions = realloc(ctx->functions, sizeof ctx->functions[0] * (ctx->nfunctions + 1))
-            ctx->functions[ctx->nfunctions++] = sig.copy()
-            exports = realloc(exports, sizeof exports[0] * (nexports + 1))
-            exports[nexports++] = ExportSymbol{
-                kind = ExportSymbolKind::Function,
-                name = sig.name,
-                signature = sig,
-            }
-        if ts->kind == AstToplevelStatementKind::FunctionDefinition:
-            sig = handle_signature(ctx, &ts->funcdef.signature)
+            sig = handle_signature(ctx, &ts->function.signature)
             ctx->functions = realloc(ctx->functions, sizeof ctx->functions[0] * (ctx->nfunctions + 1))
             ctx->functions[ctx->nfunctions++] = sig.copy()
             exports = realloc(exports, sizeof exports[0] * (nexports + 1))
@@ -324,26 +316,37 @@ def typecheck_statement(ctx: TypeContext*, statement: AstStatement*) -> void:
     if statement->kind == AstStatementKind::ExpressionStatement:
         typecheck_expression_maybe_void(ctx, &statement->expression)
 
-    elif statement->kind == AstStatementKind::ReturnWithValue:
+    elif statement->kind == AstStatementKind::Return:
         name = &ctx->current_function_signature->name[0]
 
-        if ctx->current_function_signature->return_type == NULL:
-            msg: byte[500]
+        # TODO: check for noreturn functions
+
+        return_type = ctx->current_function_signature->return_type
+        msg: byte[500]
+
+        if statement->return_value != NULL and return_type == NULL:
             snprintf(&msg[0], sizeof msg, "function '%s' cannot return a value because it was defined with '-> void'", name)
             fail(statement->location, name)
+        if statement->return_value == NULL and return_type != NULL:
+            snprintf(
+                &msg[0], sizeof msg,
+                "function '%s' must return a value because it was defined with '-> %s'",
+                name, &return_type->name[0])
+            fail(statement->location, name)
 
-        cast_error_msg: byte[500]
-        snprintf(
-            &cast_error_msg[0], sizeof cast_error_msg,
-            "attempting to return a value of type <from> from function '%s' defined with '-> <to>'",
-            name,
-        )
-        typecheck_expression_with_implicit_cast(
-            ctx,
-            &statement->return_value,
-            ctx->current_function_signature->return_type,
-            &cast_error_msg[0],
-        )
+        if statement->return_value != NULL:
+            cast_error_msg: byte[500]
+            snprintf(
+                &cast_error_msg[0], sizeof cast_error_msg,
+                "attempting to return a value of type <from> from function '%s' defined with '-> <to>'",
+                name,
+            )
+            typecheck_expression_with_implicit_cast(
+                ctx,
+                statement->return_value,
+                return_type,
+                &cast_error_msg[0],
+            )
 
     else:
         assert(False)
@@ -355,13 +358,13 @@ def typecheck_body(ctx: TypeContext*, body: AstBody*) -> void:
 def typecheck_stage3_function_and_method_bodies(ctx: TypeContext*, ast_file: AstFile*) -> void:
     for i = 0; i < ast_file->body_len; i++:
         ts = &ast_file->body[i]
-        if ts->kind != AstToplevelStatementKind::FunctionDefinition:
+        if ts->kind != AstToplevelStatementKind::Function or ts->function.body.nstatements == 0:
             continue
 
-        sig = ctx->find_function(&ts->funcdef.signature.name[0])
+        sig = ctx->find_function(&ts->function.signature.name[0])
         assert(sig != NULL)
 
         assert(ctx->current_function_signature == NULL)
         ctx->current_function_signature = sig
-        typecheck_body(ctx, &ts->funcdef.body)
+        typecheck_body(ctx, &ts->function.body)
         ctx->current_function_signature = NULL

src/build_cfg.c

@@ -830,15 +830,13 @@ static void build_statement(struct State *st, const AstStatement *stmt)
         break;
     }
 
-    case AST_STMT_RETURN_VALUE:
-    {
-        const LocalVariable *retvalue = build_expression(st, &stmt->data.expression);
-        const LocalVariable *retvariable = find_local_var(st, "return");
-        assert(retvariable);
-        add_unary_op(st, stmt->location, CF_VARCPY, retvalue, retvariable);
-    }
-    __attribute__((fallthrough));
-    case AST_STMT_RETURN_WITHOUT_VALUE:
+    case AST_STMT_RETURN:
+        if (stmt->data.returnvalue) {
+            const LocalVariable *retvalue = build_expression(st, stmt->data.returnvalue);
+            const LocalVariable *retvariable = find_local_var(st, "return");
+            assert(retvariable);
+            add_unary_op(st, stmt->location, CF_VARCPY, retvalue, retvariable);
+        }
         st->current_block->iftrue = &st->cfg->end_block;
         st->current_block->iffalse = &st->cfg->end_block;
         st->current_block = add_block(st);  // an unreachable block
@@ -908,8 +906,8 @@ CfGraphFile build_control_flow_graphs(AstToplevelNode *ast, FileTypes *filetypes
     struct State st = { .filetypes = filetypes };
 
     while (ast->kind != AST_TOPLEVEL_END_OF_FILE) {
-        if(ast->kind == AST_TOPLEVEL_DEFINE_FUNCTION) {
-            CfGraph *g = build_function_or_method(&st, NULL, ast->data.funcdef.signature.name, &ast->data.funcdef.body);
+        if(ast->kind == AST_TOPLEVEL_FUNCTION && ast->data.function.body.nstatements > 0) {
+            CfGraph *g = build_function_or_method(&st, NULL, ast->data.function.signature.name, &ast->data.function.body);
             Append(&result.graphs, g);
         }
 
@@ -923,7 +921,7 @@ CfGraphFile build_control_flow_graphs(AstToplevelNode *ast, FileTypes *filetypes
             }
             assert(classtype);
 
-            for (AstFunctionDef *m = ast->data.classdef.methods.ptr; m < End(ast->data.classdef.methods); m++) {
+            for (AstFunction *m = ast->data.classdef.methods.ptr; m < End(ast->data.classdef.methods); m++) {
                 CfGraph *g = build_function_or_method(&st, classtype, m->signature.name, &m->body);
                 Append(&result.graphs, g);
             }