ack/lang/cem/cemcom/l_state.str
1989-03-06 15:17:39 +00:00

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/*
* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
* See the copyright notice in the ACK home directory, in the file "Copyright".
*/
/* $Header$ */
/* Lint state stack */
/* These datastructures are used to implement a stack on which the
* state of automatic variables (including register variables) is
* kept.
* In this way it is possible to account for the flow of
* control of the program.
*/
#define TEST_VAR 0 /* not a constant */
#define TEST_TRUE 1 /* always true */
#define TEST_FALSE 2 /* always false */
struct loop_state { /* used in lint_end_state only */
int lps_test; /* is the test a constant? */
struct state *lps_body;
struct state *lps_loop;
};
struct switch_state { /* used in lint_end_state only */
struct state *sws_case;
struct state *sws_break;
int sws_default_met;
};
/* This union describes the (possibly incomplete) state at the end of the
mentioned construct.
*/
union lint_end_state { /* used in lint_stack_entry only */
struct state *ule_if;
struct loop_state ule_loop;
struct switch_state ule_switch;
};
struct lint_stack_entry {
struct lint_stack_entry *next;
struct lint_stack_entry *ls_previous;
int ls_level;
struct state *ls_current; /* used by all classes */
short ls_class; /* IF, WHILE, DO, FOR, SWITCH, CASE */
union lint_end_state ls_end;
};
/* ALLOCDEF "lint_stack_entry" 10 */
/* macros to access the union */
#define LS_IF ls_end.ule_if
#define LS_TEST ls_end.ule_loop.lps_test
#define LS_BODY ls_end.ule_loop.lps_body
#define LS_LOOP ls_end.ule_loop.lps_loop
#define LS_CASE ls_end.ule_switch.sws_case
#define LS_BREAK ls_end.ule_switch.sws_break
#define LS_DEFAULT_MET ls_end.ule_switch.sws_default_met
/* describes a branch in the program, with its local idfs */
struct state {
struct state *next; /* only used by memory allocator */
struct auto_def *st_auto_list;
int st_notreached; /* set if not reached */
int st_warned; /* set if warning issued */
};
/* ALLOCDEF "state" 15 */
/* describes the state of a local idf in a given branch of the program */
struct auto_def {
struct auto_def *next;
struct idf *ad_idf;
struct def *ad_def;
int ad_used;
int ad_set;
int ad_maybe_set;
};
/* ALLOCDEF "auto_def" 20 */
/* describes the state of an idf during expression evaluation */
struct expr_state { /*actually concerns idfs only */
struct expr_state *next;
struct idf *es_idf; /* the idf with its offset */
arith es_offset;
int es_used; /* value has been used */
int es_referred; /* address has been taken */
int es_set; /* has been assigned to */
};
/* ALLOCDEF "expr_state" 20 */