declaration.h

一个编译器修改的例子

#ifndef DECLARATION_H
#define DECLARATION_H

typedef struct declaration Declaration;

#include "bool.h"
#include "list.h"
#include "scope.h"
#include "statement.h"
#include "token.h"
#include "type.h"


typedef enum
{
    subprog_decl,
    var_decl,
    record_decl
}
Decl_subtype;


/* Declarations are stored in 'Declaration'-type structures. The
 * subtype field indicates whether the declaration is a subprogram or
 * a variable. Depending on the type, the union un contains fields
 * specific to variables or subprogrammes. These should be accessed
 * using the VAR_DECL and SUBPROG_DECL defines!
 */

struct declaration
{
    Decl_subtype	subtype;
    Token		*token;

    union
    {
	struct subprog_decl
	{
	    Statement	*body;
	    Scope	*formal_args_scope;
	    List	*formal_args;
	    Type	*type;
	    Type	*return_type; /* void_type if procedure */
	    Declaration *redeclaration;
	    Bool	has_been_defined;
		int		offset;
	}
	subprog_decl;

	struct
	{
	    Type	*type;
		int		offset;
	}
	var_decl;
	
	struct
	{
		Scope *member_scope;
		List *var_list;
		Type	*type;
		int		offset;
	}
	record_decl;
    }
    un;
};

#define SUBPROG_DECL(d)	((d)->un.subprog_decl)
#define VAR_DECL(d)	((d)->un.var_decl)
#define RECORD_DECL(d)	((d)->un.record_decl)


/* The global_declarations pointer is used to store the AST; it is a list
 * containing Declaration structures. It is set by the start rule 'program' in
 * the yacc specification (grammar.y).
 */
extern List *global_declarations;


Declaration *new_subprogram_declaration(Token *);

Declaration *new_var_declaration(Token *);
Declaration *new_record_declaration(Token *, List *);
void	    delete_declaration(Declaration *);
void	    delete_declaration_list(List *);
void 	bepaal_offset(Declaration *decl);
void	arguments_offset(Expression *expr);
void	    type_check_declaration(Declaration *);
void arguments_on_stack(Declaration *decl, int offset);
		/* Calling type_check_declaration_list(global_declarations)
		 * is the start of the type checking phase. It recursively
		 * type checks all the nodes in the AST. When this function
   		 * returns, the type checking phase has completed
		 */

void	    type_check_declaration_list(List *);


void	    generate_declaration(Declaration *);
		/* Calling generate_declaration_list(global_declarations)
		 * is the start of the code generation phase. It generates
		 * code for every node in the AST by (recursively) calling
		 * other generate_ functions. When this function returns,
		 * all code is generated, except for the string constant
		 * list, which is generated seperately.
		 */
void	    generate_declaration_list(List *);
#endif