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* src/conflicts.c (log_resolution): Accept the rule involved in

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the sr conflicts instead of the lookahead number that points to
that rule.
(flush_reduce): Accept the current lookahead vector as argument,
instead of the index in LA.
(resolve_sr_conflict): Accept the current number of lookahead
bitset to consider for the STATE, instead of the index in LA.
(set_conflicts): Adjust.
* src/lalr.c, src/lalr.h, src/state.h: Comment changes.
This commit is contained in:
Akim Demaille
2002-06-15 18:24:08 +00:00
parent c026349221
commit 9801d40c50
5 changed files with 53 additions and 31 deletions
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13
ChangeLog
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@@ -1,3 +1,16 @@
2002-06-15 Akim Demaille <akim@epita.fr>
* src/conflicts.c (log_resolution): Accept the rule involved in
the sr conflicts instead of the lookahead number that points to
that rule.
(flush_reduce): Accept the current lookahead vector as argument,
instead of the index in LA.
(resolve_sr_conflict): Accept the current number of lookahead
bitset to consider for the STATE, instead of the index in LA.
(set_conflicts): Adjust.
* src/lalr.c, src/lalr.h, src/state.h: Comment changes.
2002-06-15 Akim Demaille <akim@epita.fr>
* src/state.h (state_t): Replace the `lookaheadsp' member, a

51
src/conflicts.c
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@@ -52,8 +52,13 @@ enum conflict_resolution_e
};
/*----------------------------------------------------------------.
| Explain how an SR conflict between TOKEN and RULE was resolved: |
| RESOLUTION. |
`----------------------------------------------------------------*/
static inline void
log_resolution (int lookahead, int token,
log_resolution (rule_t *rule, int token,
enum conflict_resolution_e resolution)
{
if (report_flag & report_solved_conflicts)
@@ -66,7 +71,7 @@ log_resolution (int lookahead, int token,
obstack_fgrow2 (&solved_conflicts_obstack,
_("\
Conflict between rule %d and token %s resolved as shift"),
LArule[lookahead]->number,
rule->number,
symbols[token]->tag);
break;
case reduce_resolution:
@@ -74,14 +79,14 @@ log_resolution (int lookahead, int token,
obstack_fgrow2 (&solved_conflicts_obstack,
_("\
Conflict between rule %d and token %s resolved as reduce"),
LArule[lookahead]->number,
rule->number,
symbols[token]->tag);
break;
case nonassoc_resolution:
obstack_fgrow2 (&solved_conflicts_obstack,
_("\
Conflict between rule %d and token %s resolved as an error"),
LArule[lookahead]->number,
rule->number,
symbols[token]->tag);
break;
}
@@ -92,7 +97,7 @@ log_resolution (int lookahead, int token,
case shift_resolution:
obstack_fgrow2 (&solved_conflicts_obstack,
" (%s < %s)",
LArule[lookahead]->prec->tag,
rule->prec->tag,
symbols[token]->tag);
break;
@@ -100,7 +105,7 @@ log_resolution (int lookahead, int token,
obstack_fgrow2 (&solved_conflicts_obstack,
" (%s < %s)",
symbols[token]->tag,
LArule[lookahead]->prec->tag);
rule->prec->tag);
break;
case left_resolution:
@@ -151,9 +156,9 @@ flush_shift (state_t *state, int token)
`-------------------------------------------------------------------*/
static void
flush_reduce (int lookahead, int token)
flush_reduce (bitset lookaheads, int token)
{
bitset_reset (LA[lookahead], token);
bitset_reset (lookaheads, token);
}
@@ -162,19 +167,23 @@ flush_reduce (int lookahead, int token)
| precedence declarations. It has already been checked that the |
| rule has a precedence. A conflict is resolved by modifying the |
| shift or reduce tables so that there is no longer a conflict. |
| |
| LOOKAHEAD is the number of the lookahead bitset to consider. |
`------------------------------------------------------------------*/
static void
resolve_sr_conflict (state_t *state, int lookahead)
{
int i;
/* find the rule to reduce by to get precedence of reduction */
int redprec = LArule[lookahead]->prec->prec;
/* Find the rule to reduce by to get precedence of reduction. */
rule_t *redrule = state->lookaheads_rule[lookahead];
int redprec = redrule->prec->prec;
bitset lookaheads = state->lookaheads[lookahead];
errs *errp = errs_new (ntokens + 1);
errp->nerrs = 0;
for (i = 0; i < ntokens; i++)
if (bitset_test (LA[lookahead], i)
if (bitset_test (lookaheads, i)
&& bitset_test (lookaheadset, i)
&& symbols[i]->prec)
{
@@ -183,13 +192,13 @@ resolve_sr_conflict (state_t *state, int lookahead)
The precedence of shifting is that of token i. */
if (symbols[i]->prec < redprec)
{
log_resolution (lookahead, i, reduce_resolution);
log_resolution (redrule, i, reduce_resolution);
flush_shift (state, i);
}
else if (symbols[i]->prec > redprec)
{
log_resolution (lookahead, i, shift_resolution);
flush_reduce (lookahead, i);
log_resolution (redrule, i, shift_resolution);
flush_reduce (lookaheads, i);
}
else
/* Matching precedence levels.
@@ -200,19 +209,19 @@ resolve_sr_conflict (state_t *state, int lookahead)
switch (symbols[i]->assoc)
{
case right_assoc:
log_resolution (lookahead, i, right_resolution);
flush_reduce (lookahead, i);
log_resolution (redrule, i, right_resolution);
flush_reduce (lookaheads, i);
break;
case left_assoc:
log_resolution (lookahead, i, left_resolution);
log_resolution (redrule, i, left_resolution);
flush_shift (state, i);
break;
case non_assoc:
log_resolution (lookahead, i, nonassoc_resolution);
log_resolution (redrule, i, nonassoc_resolution);
flush_shift (state, i);
flush_reduce (lookahead, i);
flush_reduce (lookaheads, i);
/* Record an explicit error for this token. */
errp->errs[errp->nerrs++] = i;
break;
@@ -254,13 +263,13 @@ set_conflicts (state_t *state)
/* Loop over all rules which require lookahead in this state. First
check for shift-reduce conflict, and try to resolve using
precedence */
precedence. */
for (i = 0; i < state->nlookaheads; ++i)
if (state->lookaheads_rule[i]->prec
&& state->lookaheads_rule[i]->prec->prec
&& !bitset_disjoint_p (state->lookaheads[i], lookaheadset))
{
resolve_sr_conflict (state, (state->lookaheads - LA) + i);
resolve_sr_conflict (state, i);
break;
}

4
src/lalr.c
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@@ -559,8 +559,8 @@ states_lookaheads_initialize (void)
bitsetv pLA = LA;
rule_t **pLArule = LArule;
/* Count the number of lookaheads required for each state
(NLOOKAHEADS member). */
/* Initialize the members LOOKAHEADS and LOOKAHEADS_RULE for each
state. */
for (i = 0; i < nstates; i++)
{
states[i]->lookaheads = pLA;

2
src/lalr.h
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@@ -63,7 +63,7 @@ extern short *to_state;
extern rule_t **LArule;
/* LA is a lr by ntokens matrix of bits. LA[l, i] is 1 if the rule
/* LA is a LR by NTOKENS matrix of bits. LA[l, i] is 1 if the rule
LAruleno[l] is applicable in the appropriate state when the next
token is symbol i. If LA[l, i] and LA[l, j] are both 1 for i != j,
it is a conflict. */

14
src/state.h
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@@ -30,19 +30,19 @@
state. These symbols at these items are the allowable inputs that
can follow now.
A core represents one state. States are numbered in the number
A core represents one state. States are numbered in the NUMBER
field. When generate_states is finished, the starting state is
state 0 and nstates is the number of states. (A transition to a
state whose state number is nstates indicates termination.) All
the cores are chained together and first_state points to the first
one (state 0).
state 0 and NSTATES is the number of states. (FIXME: This sentence
is no longer true: A transition to a state whose state number is
NSTATES indicates termination.) All the cores are chained together
and FIRST_STATE points to the first one (state 0).
For each state there is a particular symbol which must have been
the last thing accepted to reach that state. It is the
accessing_symbol of the core.
ACCESSING_SYMBOL of the core.
Each core contains a vector of NITEMS items which are the indices
in the ritems vector of the items that are selected in this state.
in the RITEMS vector of the items that are selected in this state.
The link field is used for chaining symbols that hash states by
their itemsets. This is for recognizing equivalent states and