From: Akim Demaille Date: Wed, 4 Jan 2006 09:18:37 +0000 (+0000) Subject: Also warn about non-used mid-rule values. X-Git-Tag: v2.3b~515 X-Git-Url: https://git.saurik.com/bison.git/commitdiff_plain/84866159725a9df9febc1050643c0355eba5916c Also warn about non-used mid-rule values. * src/symlist.h, src/symlist.c (symbol_list): Add a mid_rule member. (symbol_list_new): Adjust. * src/reader.c (symbol_typed_p): New. (grammar_rule_check): Use it. (grammar_midrule_action): Bind a mid-rule LHS to its rule. Check its rule. * tests/input.at (AT_CHECK_UNUSED_VALUES): New. Use it. * tests/actions.at (Exotic Dollars): Adjust. --- diff --git a/ChangeLog b/ChangeLog index a7553e32..1fef6bb8 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,17 @@ +2006-01-04 Akim Demaille + + Also warn about non-used mid-rule values. + * src/symlist.h, src/symlist.c (symbol_list): Add a mid_rule + member. + (symbol_list_new): Adjust. + * src/reader.c (symbol_typed_p): New. + (grammar_rule_check): Use it. + (grammar_midrule_action): Bind a mid-rule LHS to its rule. + Check its rule. + * tests/input.at (AT_CHECK_UNUSED_VALUES): New. + Use it. + * tests/actions.at (Exotic Dollars): Adjust. + 2006-01-04 Akim Demaille * src/reader.c (grammar_midrule_action): If $$ is set in a diff --git a/NEWS b/NEWS index 2b7c1013..784efeb7 100644 --- a/NEWS +++ b/NEWS @@ -26,6 +26,17 @@ Changes in version 2.1a: | exp "+" exp { $$ = $1; (void) $3; } ; + If there are mid-rule actions, the warning is issued if no action + uses it. The following triggers no warning: $1 and $3 are used. + + exp: exp { push ($1); } '+' exp { push ($3); sum (); }; + + Mid-rule actions that use $$ cause the corresponding value to be + set, therefore the following action must use it. The following rule + triggers a warning about $2. + + exp: '1' { $$ = 1; } '+' exp { $$ = $1 + $4; }; + The warning is intended to help catching lost values and memory leaks. If a value is ignored, its associated memory typically is not reclaimed. diff --git a/src/reader.c b/src/reader.c index c0547e08..573cb14d 100644 --- a/src/reader.c +++ b/src/reader.c @@ -210,6 +210,20 @@ grammar_current_rule_begin (symbol *lhs, location loc) } +/*-----------------------------------------------------------------. +| A symbol is typed if it has a declared %type, or if it is a | +| mid-rule symbol (i.e., the generated LHS replacing a mid-rule | +| action) that was assigned to, as in `exp: { $$ = 1; } { $$ = $1; | +| }'. | +`-----------------------------------------------------------------*/ + +static bool +symbol_typed_p (const symbol_list *s) +{ + return (s->sym->type_name + || s->mid_rule && s->mid_rule->used); +} + /*----------------------------------------------------------------. | Check that the rule R is properly defined. For instance, there | | should be no type clash on the default action. | @@ -251,7 +265,7 @@ grammar_rule_check (const symbol_list *r) int n = 0; for (; l && l->sym; l = l->next, ++n) if (! (l->used - || !l->sym->type_name + || !symbol_typed_p (l) /* The default action, $$ = $1, `uses' both. */ || (!r->action && (n == 0 || n == 1)))) { @@ -318,14 +332,16 @@ grammar_midrule_action (void) grammar = midrule; /* End the dummy's rule. */ - previous_rule_end = symbol_list_new (NULL, dummy_location); - previous_rule_end->next = current_rule; + midrule->next = symbol_list_new (NULL, dummy_location); + grammar_rule_check (midrule); + midrule->next->next = current_rule; - midrule->next = previous_rule_end; + previous_rule_end = midrule->next; /* Insert the dummy nonterminal replacing the midrule action into - the current rule. */ + the current rule. Bind it to its dedicated rule. */ grammar_current_rule_symbol_append (dummy, dummy_location); + grammar_end->mid_rule = midrule; } /* Set the precedence symbol of the current rule to PRECSYM. */ diff --git a/src/symlist.c b/src/symlist.c index a277f36e..eeb54e5a 100644 --- a/src/symlist.c +++ b/src/symlist.c @@ -1,6 +1,6 @@ /* Lists of symbols for Bison - Copyright (C) 2002, 2005 Free Software Foundation, Inc. + Copyright (C) 2002, 2005, 2006 Free Software Foundation, Inc. This file is part of Bison, the GNU Compiler Compiler. @@ -38,6 +38,8 @@ symbol_list_new (symbol *sym, location loc) res->sym = sym; res->location = loc; + res->mid_rule = NULL; + res->action = NULL; res->used = false; diff --git a/src/symlist.h b/src/symlist.h index 480c97d4..bff56683 100644 --- a/src/symlist.h +++ b/src/symlist.h @@ -32,6 +32,10 @@ typedef struct symbol_list symbol *sym; location location; + /* If this symbol is the generated lhs for a mid-rule, a pointer to + that mid-rule. */ + struct symbol_list *mid_rule; + /* The action is attached to the LHS of a rule. */ const char *action; location action_location; diff --git a/tests/actions.at b/tests/actions.at index 35df2319..7a03fb00 100644 --- a/tests/actions.at +++ b/tests/actions.at @@ -113,6 +113,7 @@ AT_DATA_GRAMMAR([[input.y]], exp: a_1 a_2 { $$ = 3; } { $$ = $3 + 1; } a_5 sum_of_the_five_previous_values { + USE (($1, $2, $3, $4, $5)); printf ("%d\n", $6); } ; @@ -146,11 +147,7 @@ main (void) } ]]) -AT_CHECK([bison -d -v -o input.c input.y], 0, [], -[input.y:30.6-34.5: warning: unused value: $1 -input.y:30.6-34.5: warning: unused value: $2 -input.y:30.6-34.5: warning: unused value: $5 -]) +AT_CHECK([bison -d -v -o input.c input.y], 0) AT_COMPILE([input]) AT_PARSER_CHECK([./input], 0, [[15 diff --git a/tests/input.at b/tests/input.at index f533ef3a..cfff34c8 100644 --- a/tests/input.at +++ b/tests/input.at @@ -86,51 +86,80 @@ AT_CLEANUP ## Unused values. ## ## --------------- ## -AT_SETUP([Unused values]) +m4_define([AT_CHECK_UNUSED_VALUES], +[AT_SETUP([Unused values]) AT_DATA([input.y], [[%token INT %type exp %% exp: - INT { } INT { } INT { } -/* Ideally we would like to complain also about $2 and $4 here, but - it's hard to implement. */ -| INT { $$ } INT { $$ } INT { } -| INT { $1 } INT { } INT { } -| INT { } INT { $1 } INT { } -| INT { } INT { } INT { $1 } -| INT { } INT { } INT { $$ = $1 + $3 + $5; } + $1 +| INT ; ]]) AT_CHECK([bison input.y], [], [], -[[input.y:5.3-25: warning: unset value: $$ +[[$2]]) + +AT_CLEANUP +]) + +AT_CHECK_UNUSED_VALUES([INT { } INT { } INT { }], +[input.y:5.3-25: warning: unset value: $$ input.y:5.3-25: warning: unused value: $1 input.y:5.3-25: warning: unused value: $3 input.y:5.3-25: warning: unused value: $5 -input.y:8.3-31: warning: unset value: $$ -input.y:8.3-31: warning: unused value: $1 -input.y:8.3-31: warning: unused value: $3 -input.y:8.3-31: warning: unused value: $5 -input.y:9.3-28: warning: unset value: $$ -input.y:9.3-28: warning: unused value: $3 -input.y:9.3-28: warning: unused value: $5 -input.y:10.3-28: warning: unset value: $$ -input.y:10.3-28: warning: unused value: $3 -input.y:10.3-28: warning: unused value: $5 -input.y:11.3-29: warning: unset value: $$ -input.y:11.3-29: warning: unused value: $3 -input.y:11.3-29: warning: unused value: $5 -input.y: conflicts: 1 reduce/reduce -input.y:8.7-12: warning: rule never reduced because of conflicts: @3: /* empty */ -input.y:9.7-12: warning: rule never reduced because of conflicts: @5: /* empty */ -input.y:10.7-9: warning: rule never reduced because of conflicts: @7: /* empty */ -input.y:11.7-9: warning: rule never reduced because of conflicts: @9: /* empty */ -input.y:12.7-9: warning: rule never reduced because of conflicts: @11: /* empty */ -]]) +]) + +AT_CHECK_UNUSED_VALUES([INT { $1 } INT { } INT { }], +[input.y:5.3-28: warning: unset value: $$ +input.y:5.3-28: warning: unused value: $3 +input.y:5.3-28: warning: unused value: $5 +]) + +AT_CHECK_UNUSED_VALUES([INT { } INT { $1 } INT { }], +[input.y:5.3-28: warning: unset value: $$ +input.y:5.3-28: warning: unused value: $3 +input.y:5.3-28: warning: unused value: $5 +]) + +AT_CHECK_UNUSED_VALUES([INT { } INT { } INT { $1 }], +[input.y:5.3-29: warning: unset value: $$ +input.y:5.3-29: warning: unused value: $3 +input.y:5.3-29: warning: unused value: $5 +]) + +AT_CHECK_UNUSED_VALUES([INT { } INT { } INT { $$ = $1 + $3 + $5; }]) + +# Checking mid-rule values. +AT_CHECK_UNUSED_VALUES([INT { $$ } INT { $$ } INT { }], +[input.y:5.3-31: warning: unset value: $$ +input.y:5.3-31: warning: unused value: $1 +input.y:5.3-31: warning: unused value: $2 +input.y:5.3-31: warning: unused value: $3 +input.y:5.3-31: warning: unused value: $4 +input.y:5.3-31: warning: unused value: $5 +]) + +AT_CHECK_UNUSED_VALUES([INT { $$ } INT { $$ = $2 } INT { }], +[input.y:5.3-36: warning: unset value: $$ +input.y:5.3-36: warning: unused value: $1 +input.y:5.3-36: warning: unused value: $3 +input.y:5.3-36: warning: unused value: $4 +input.y:5.3-36: warning: unused value: $5 +]) + +# AT_CHECK_UNUSED_VALUES([INT { $$ } { $$ = $2 } { }], +# [input.y:5.3-36: warning: unset value: $$ +# input.y:5.3-36: warning: unused value: $1 +# input.y:5.3-36: warning: unused value: $3 +# input.y:5.3-36: warning: unused value: $4 +# input.y:5.3-36: warning: unused value: $5 +# ]) + +AT_CHECK_UNUSED_VALUES([INT { $$ = $1 } INT { $$ = $2 + $3 } INT { $$ = $4 + $5 }]) -AT_CLEANUP ## ---------------------- ##