path: root/prepare.c

/* Oort
 * Copyright 2007, Soren Sandmann Pedersen
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include "ast.h"

#include <stdlib.h>

/*
 * This pass does various stuff that doesn't really belong elsewhere
 *   - it hooks up parent pointers
 *   - it weeds out break/continue/return in wrong places
 *   - it gathers information about definitions
 */

typedef struct info_t info_t;
struct info_t
{
    GPtrArray       *functions;
    GPtrArray       *classes;
};

static gboolean prepare_statement (ast_statement_t *statement,
				   ast_t           *parent,
				   info_t          *info);
static gboolean prepare_definition (ast_definition_t *definition,
				    ast_t            *parent,
				    info_t           *info);

static void
set_parent (ast_t *ast, ast_t *parent)
{
    ast_ensure_ast (ast);

    ast->common.parent = parent;

    if (parent)
    {
	ast_ensure_ast (parent);

	g_queue_push_tail (parent->common.children, ast);
    }
}

static gboolean
prepare_void_type (ast_type_spec_t *type_spec)
{
    ast_t *parent = ((ast_t *)type_spec)->common.parent;

    if (ast_is (parent, AST_DEFINITION, AST_FUNCTION_DEFINITION)	&&
	parent->definition.function.return_type == type_spec)
    {
	return TRUE;
    }

    if (ast_is (parent, AST_TYPE_SPEC, AST_FUNCTION_TYPE)		&&
	parent->type_spec.function.return_ == type_spec)
    {
	return TRUE;
    }

    return report_error (
	"void is allowed only as the return type of a function\n");
}

static gboolean
prepare_type_spec (ast_type_spec_t *type_spec,
		   ast_t           *parent,
		   info_t          *info)
{
    int i;

    set_parent ((ast_t *)type_spec, parent);
    parent = ((ast_t *)type_spec);

    switch (type_spec->common.type)
    {
    case AST_FUNCTION_TYPE:
	if (!prepare_type_spec (type_spec->function.return_, parent, info))
	    return FALSE;
	for (i = 0; type_spec->function.args[i] != NULL; ++i)
	{
	    if (!prepare_type_spec (type_spec->function.args[i], parent, info))
		return FALSE;
	}
	break;
    case AST_ARRAY_TYPE:
	if (!prepare_type_spec (type_spec->array.child_type, parent, info))
	    return FALSE;
	break;
    case AST_VOID_TYPE:
	if (!prepare_void_type (type_spec))
	    return FALSE;
	break;
    case AST_LABEL_TYPE:
    case AST_OBJECT_TYPE:
    case AST_INT32_TYPE:
    case AST_DOUBLE_TYPE:
    case AST_BOOL_TYPE:
    case AST_IDENTIFIER_TYPE:
    case AST_NULL_TYPE:
    case AST_STRING_TYPE:
    case AST_INFERRED_TYPE:
	break;
    }

    return TRUE;
}

static gboolean
prepare_function (ast_function_definition_t *function,
		  ast_t                     *parent,
		  info_t                    *info)
{
    int i;

    g_ptr_array_add (info->functions, function);

    if (!prepare_type_spec (function->return_type, parent, info))
	return FALSE;

    for (i = 0; function->parameters[i]; ++i)
    {
	ast_variable_definition_t *parameter;

	parameter = function->parameters[i];

	parameter->parameter = TRUE;
	
	if (!prepare_definition ((ast_definition_t *)parameter, parent, info))
	    return FALSE;
    }

    if (!prepare_statement (function->body, parent, info))
	return FALSE;

    return TRUE;
}

static gboolean
prepare_class_body (ast_statement_t        *statement,
		    ast_class_definition_t *class)
{
    switch (statement->common.type)
    {
    case AST_BLOCK_STATEMENT:
    case AST_PRINT_STATEMENT:
    case AST_LOOP_STATEMENT:
    case AST_IF_STATEMENT:
    case AST_SWITCH_STATEMENT:
    case AST_EXPRESSION_STATEMENT:
    case AST_RETURN_STATEMENT:
    case AST_GOTO_STATEMENT:
    case AST_BREAK_STATEMENT:
    case AST_CONTINUE_STATEMENT:
    case AST_LABEL_STATEMENT:
	return report_error ("Illegal statement in class\n");
	break;

    case AST_DEFINITION_STATEMENT:
    case AST_EMPTY_STATEMENT:
	break;

    case AST_COMPOUND_STATEMENT:
	if (!prepare_class_body (statement->compound.first, class))
	    return FALSE;
	if (!prepare_class_body (statement->compound.second, class))
	    return FALSE;
	break;
    }

    return TRUE;
}

static gboolean
prepare_class (ast_class_definition_t *class,
	       ast_t                  *parent,
	       info_t                 *info)
{
    g_ptr_array_add (info->classes, class);

    if (!prepare_class_body (class->statement, class))
	return FALSE;

    if (!prepare_statement (class->statement, parent, info))
	return FALSE;

    return TRUE;
}

static gboolean
prepare_definition (ast_definition_t *definition,
		    ast_t            *parent,
		    info_t           *info)
{
    ast_t *ast = (ast_t *)definition;
    ast_t *enclosing_class;
    ast_t *enclosing_function;

    set_parent (ast, parent);
    parent = ast;

    switch (definition->common.type)
    {
    case AST_VARIABLE_DEFINITION:
	if (!prepare_type_spec (definition->variable.type_spec, parent, info))
	    return FALSE;

	enclosing_class = (ast_t *)ast_enclosing_class (ast);
	enclosing_function = (ast_t *)ast_enclosing_function (ast);
	if (enclosing_class &&
	    (!enclosing_function ||
	     ast_encloses (enclosing_function, enclosing_class)))
	{
	    definition->variable.field = TRUE;
	}

	g_assert (ast->common.children->head);
	break;

    case AST_FUNCTION_DEFINITION:
	if (!prepare_function (&definition->function, parent, info))
	    return FALSE;
	break;

    case AST_CLASS_DEFINITION:
	if (!prepare_class (&definition->class, parent, info))
	    return FALSE;
	break;

    case AST_TYPE_DEFINITION:
	if (!prepare_type_spec (definition->type.type_spec, parent, info))
	    return FALSE;
	break;

    case AST_LABEL_DEFINITION:
	break;
    }

    return TRUE;
}

static gboolean
prepare_expression (ast_expression_t *expr,
		    ast_t            *parent,
		    info_t           *info)
{
    int i;
    ast_t *ast = (ast_t *)expr;

    set_parent (ast, parent);
    parent = ast;

    switch (expr->common.type)
    {
    case AST_INT_LITERAL_EXPRESSION:
    case AST_FLOAT_LITERAL_EXPRESSION:
    case AST_BOOL_LITERAL_EXPRESSION:
    case AST_STRING_LITERAL_EXPRESSION:
    case AST_NULL_EXPRESSION:
    case AST_VOID_EXPRESSION:
    case AST_IDENTIFIER_EXPRESSION:
    case AST_THIS_EXPRESSION:
	break;

    case AST_UNARY_EXPRESSION:
	if (!prepare_expression (expr->unary.expr, parent, info))
	    return FALSE;
	break;

    case AST_BINARY_EXPRESSION:
	if (!prepare_expression (expr->binary.left, parent, info))
	    return FALSE;
	if (!prepare_expression (expr->binary.right, parent, info))
	    return FALSE;
	break;

    case AST_TERNARY_EXPRESSION:
	if (!prepare_expression (expr->ternary.cond, parent, info))
	    return FALSE;
	if (!prepare_expression (expr->ternary.then_expr, parent, info))
	    return FALSE;
	if (!prepare_expression (expr->ternary.else_expr, parent, info))
	    return FALSE;
	break;

    case AST_LAMBDA_EXPRESSION:
	if (!prepare_definition ((ast_definition_t *)expr->lambda.function,
				 parent, info))
	{
	    return FALSE;
	}
	break;

    case AST_STATEMENT_EXPRESSION:
	if (!prepare_statement (expr->statement.statement, parent, info))
	    return FALSE;
	if (!prepare_expression (expr->statement.expression, parent, info))
	    return FALSE;
	break;

    case AST_NEW_EXPRESSION:
	if (!prepare_type_spec (expr->new.type, parent, info))
	    return FALSE;
	for (i = 0; expr->new.args[i]; ++i)
	{
	    if (!prepare_expression (expr->new.args[i], parent, info))
		return FALSE;
	}
	break;

    case AST_BLOCK_EXPRESSION:
	if (!prepare_expression (expr->block.body, parent, info))
	    return FALSE;
	break;

    case AST_DEFINITION_EXPRESSION:
	if (!prepare_definition (expr->definition.definition, parent, info))
	    return FALSE;
	if (!prepare_expression (expr->definition.initializer, parent, info))
	    return FALSE;
	break;

    case AST_DOT_EXPRESSION:
	if (!prepare_expression (expr->dot.left, parent, info))
	    return FALSE;
	break;

    case AST_INDEX_EXPRESSION:
	if (!prepare_expression (expr->index.left, parent, info))
	    return FALSE;
	if (!prepare_expression (expr->index.right, parent, info))
	    return FALSE;
	break;

    case AST_CALL_EXPRESSION:
	if (!prepare_expression (expr->call.callee, parent, info))
	    return FALSE;
	for (i = 0; expr->call.args[i]; ++i)
	{
	    if (!prepare_expression (expr->call.args[i], parent, info))
		return FALSE;
	}
	break;
    }

    return TRUE;
}

static gboolean
prepare_case (ast_case_t *case_,
	      ast_t      *parent,
	      info_t     *info)
{
    ast_t *ast = (ast_t *)case_;
    set_parent (ast, parent);
    parent = ast;

    switch (case_->common.type)
    {
    case AST_EXPRESSION_CASE:
	if (!prepare_expression (case_->expression.expr, parent, info))
	    return FALSE;
	break;

    case AST_DEFAULT_CASE:
	break;
    }

    if (!prepare_statement (case_->common.statement, parent, info))
	return FALSE;

    return TRUE;
}

static gboolean
prepare_statement (ast_statement_t *statement,
		   ast_t           *parent,
		   info_t          *info)
{
    int i;
    ast_t *enclosing, *function;
    ast_t *ast = (ast_t *)statement;
    set_parent (ast, parent);
    parent = ast;

    switch (statement->common.type)
    {
    case AST_DEFINITION_STATEMENT:
	if (!prepare_definition (statement->definition.def, parent, info))
	    return FALSE;
	break;

    case AST_LOOP_STATEMENT:
	if (!prepare_statement (statement->loop.init, parent, info))
	    return FALSE;
	if (!prepare_expression (statement->loop.condition, parent, info))
	    return FALSE;
	if (!prepare_statement (statement->loop.body, parent, info))
	    return FALSE;
	if (!prepare_statement (statement->loop.increment, parent, info))
	    return FALSE;
	break;

    case AST_IF_STATEMENT:
	if (!prepare_expression (statement->if_.condition, parent, info))
	    return FALSE;
	if (!prepare_statement (statement->if_.then_part, parent, info))
	    return FALSE;
	if (!prepare_statement (statement->if_.else_part, parent, info))
	    return FALSE;
	break;

    case AST_SWITCH_STATEMENT:
	if (!prepare_expression (statement->switch_.condition, parent, info))
	    return FALSE;
	for (i = 0; statement->switch_.cases[i] != NULL; ++i)
	{
	    if (!prepare_case (statement->switch_.cases[i], parent, info))
		return FALSE;
	}
	break;

    case AST_COMPOUND_STATEMENT:
	if (!prepare_statement (statement->compound.first, parent, info))
	    return FALSE;
	if (!prepare_statement (statement->compound.second, parent, info))
	    return FALSE;
	break;

    case AST_BLOCK_STATEMENT:
	if (!prepare_statement (statement->block.body, parent, info))
	    return FALSE;
	break;

    case AST_PRINT_STATEMENT:
	for (i = 0; statement->print.exprs[i]; ++i)
	{
	    if (!prepare_expression (statement->print.exprs[i], parent, info))
		return FALSE;
	}
	break;

    case AST_EXPRESSION_STATEMENT:
	if (!prepare_expression (statement->expression.expr, parent, info))
	    return FALSE;
	break;

    case AST_RETURN_STATEMENT:
	if (!prepare_expression (statement->return_.expr, parent, info))
	    return FALSE;
	if (!ast_enclosing_function (ast))
	    return report_error ("return outside of function\n");
	break;

    case AST_BREAK_STATEMENT:
    case AST_CONTINUE_STATEMENT:
	if (!(enclosing = (ast_t *)ast_enclosing_loop (ast)))
	{
	    if (statement->common.type == AST_CONTINUE_STATEMENT)
	    {
		return report_error ("continue not inside for, while, or do\n");
	    }
	    else
	    {
		if (!(enclosing = (ast_t *)ast_enclosing_switch (ast)))
		{
		    return report_error (
			"break not inside for, while, do, or switch\n");
		}
	    }
	}

	if ((function = (ast_t *)ast_enclosing_function (ast)))
	{
	    if (ast_encloses (enclosing, function))
	    {
		/* FIXME: We could actually allow this since we support
		 * gotos out of the current function; the question is
		 * whether that would be more confusing than useful.
		 */
		return report_error (
		    "break or continue cannot be used with a do, while, for, "
		    "or switch which is outside the current function\n");
	    }
	}
	break;
    case AST_GOTO_STATEMENT:
	if (!prepare_expression (statement->goto_.target, parent, info))
	    return FALSE;
	break;
    case AST_LABEL_STATEMENT:
	statement->label.definition = ast_definition_new_label (
	    statement->label.label, &(statement->label));

	if (!prepare_definition (statement->label.definition, parent, info))
	    return FALSE;
	break;

    case AST_EMPTY_STATEMENT:
	break;
    }

    return TRUE;
}

gboolean
prepare (ast_t *ast)
{
    info_t info;
    ast_program_t *program = &ast->program;

    set_parent (ast, NULL);

    info.functions = g_ptr_array_new ();
    info.classes = g_ptr_array_new ();

    if (!prepare_statement (program->statement, ast, &info))
	return FALSE;

    g_ptr_array_add (info.functions, NULL);
    g_ptr_array_add (info.classes, NULL);

    program->functions =
	(ast_function_definition_t **)info.functions->pdata;

    return TRUE;
}