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-Wempty-rule: diagnose empty rules without %empty

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* src/complain.h, src/complain.c (warning_empty_rule, Wempty_rule):
New warning category.
(warnings_args, warnings_types): Adjust.
* src/reader.c (grammar_rule_check): Check the empty rules are
flagged by %empty.
* tests/actions.at (Implicitly empty rule): New.
* tests/existing.at: Add expected warnings.
This commit is contained in:
Akim Demaille
2013-02-09 18:26:38 +01:00
parent 684083f065
commit f68a49ed49
6 changed files with 107 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
src/complain.c
View File

@@ -63,6 +63,7 @@ static const char * const warnings_args[] =
"conflicts-sr",
"conflicts-rr",
"deprecated",
"empty-rule",
"precedence",
"other",
"all",
@@ -78,6 +79,7 @@ static const int warnings_types[] =
Wconflicts_sr,
Wconflicts_rr,
Wdeprecated,
Wempty_rule,
Wprecedence,
Wother,
Wall,

2
src/complain.h
View File

@@ -35,6 +35,7 @@ typedef enum
warning_yacc, /**< POSIXME. */
warning_conflicts_sr, /**< S/R conflicts. */
warning_conflicts_rr, /**< R/R conflicts. */
warning_empty_rule, /**< Implicitly empty rules. */
warning_deprecated, /**< Obsolete constructs. */
warning_precedence, /**< Useless precedence and associativity. */
warning_other, /**< All other warnings. */
@@ -85,6 +86,7 @@ typedef enum
Wconflicts_sr = 1 << warning_conflicts_sr,
Wconflicts_rr = 1 << warning_conflicts_rr,
Wdeprecated = 1 << warning_deprecated,
Wempty_rule = 1 << warning_empty_rule,
Wprecedence = 1 << warning_precedence,
Wother = 1 << warning_other,

1
src/getargs.c
View File

@@ -327,6 +327,7 @@ Warning categories include:\n\
`conflicts-sr' S/R conflicts (enabled by default)\n\
`conflicts-rr' R/R conflicts (enabled by default)\n\
`deprecated' obsolete constructs\n\
`empty-rule' empty rules without %empty\n\
`precedence' useless precedence and associativity\n\
`other' all other warnings (enabled by default)\n\
`all' all the warnings\n\

6
src/reader.c
View File

@@ -339,6 +339,12 @@ grammar_rule_check (const symbol_list *r)
complain (&r->percent_empty_loc, complaint,
_("%%empty on non-empty rule"));
/* Check that empty rule => %empty. */
if (!(r->next && r->next->content.sym)
&& !r->midrule_parent_rule
&& !r->percent_empty_loc.start.file)
complain (&r->location, Wempty_rule, _("empty rule without %%empty"));
/* See comments in grammar_current_rule_prec_set for how POSIX
mandates this complaint. It's only for identifiers, so skip
it for char literals and strings, which are always tokens. */

22
tests/actions.at
View File

@@ -64,6 +64,28 @@ AT_PARSER_CHECK([./input], 0,
AT_CLEANUP
## ----------------------- ##
## Implicitly empty rule. ##
## ----------------------- ##
AT_SETUP([Implicitly empty rule])
AT_DATA_GRAMMAR([[1.y]],
[[%%
exp: a b;
a: /* empty. */ {};
// A mid-rule action does not count as an empty rule.
b: {} {};
]])
AT_BISON_CHECK([-fcaret -Wempty-rule 1.y], [0], [],
[[1.y:11.17-18: warning: empty rule without %empty [-Wempty-rule]
a: /* empty. */ {};
^^
]])
AT_CLEANUP
## ------------------------ ##
## Invalid uses of %empty. ##
## ------------------------ ##

79
tests/existing.at
View File

@@ -427,7 +427,17 @@ dnl don't like even `print $!4;'.
dnl BISON-STDERR
[AT_COND_CASE([[canonical LR]],
[[input.y: warning: 265 shift/reduce conflicts [-Wconflicts-sr]
[[input.y:66.10: warning: empty rule without %empty [-Wempty-rule]
input.y:169.8: warning: empty rule without %empty [-Wempty-rule]
input.y:174.12: warning: empty rule without %empty [-Wempty-rule]
input.y:179.13: warning: empty rule without %empty [-Wempty-rule]
input.y:187.15: warning: empty rule without %empty [-Wempty-rule]
input.y:201.8: warning: empty rule without %empty [-Wempty-rule]
input.y:206.21: warning: empty rule without %empty [-Wempty-rule]
input.y:220.20: warning: empty rule without %empty [-Wempty-rule]
input.y:299.13: warning: empty rule without %empty [-Wempty-rule]
input.y:322.9: warning: empty rule without %empty [-Wempty-rule]
input.y: warning: 265 shift/reduce conflicts [-Wconflicts-sr]
input.y:19.8-16: warning: useless associativity for FUNC_CALL, use %precedence [-Wprecedence]
input.y:21.8-14: warning: useless associativity for YNUMBER, use %precedence [-Wprecedence]
input.y:21.16-22: warning: useless associativity for YSTRING, use %precedence [-Wprecedence]
@@ -446,7 +456,17 @@ input.y:47.12-16: warning: useless associativity for UNARY, use %precedence [-Wp
input.y:50.7-9: warning: useless associativity for '$', use %precedence [-Wprecedence]
input.y:51.7-9: warning: useless associativity for '(', use %precedence [-Wprecedence]
input.y:51.11-13: warning: useless precedence and associativity for ')' [-Wprecedence]]],
[[input.y: warning: 65 shift/reduce conflicts [-Wconflicts-sr]
[[input.y:66.10: warning: empty rule without %empty [-Wempty-rule]
input.y:169.8: warning: empty rule without %empty [-Wempty-rule]
input.y:174.12: warning: empty rule without %empty [-Wempty-rule]
input.y:179.13: warning: empty rule without %empty [-Wempty-rule]
input.y:187.15: warning: empty rule without %empty [-Wempty-rule]
input.y:201.8: warning: empty rule without %empty [-Wempty-rule]
input.y:206.21: warning: empty rule without %empty [-Wempty-rule]
input.y:220.20: warning: empty rule without %empty [-Wempty-rule]
input.y:299.13: warning: empty rule without %empty [-Wempty-rule]
input.y:322.9: warning: empty rule without %empty [-Wempty-rule]
input.y: warning: 65 shift/reduce conflicts [-Wconflicts-sr]
input.y:19.8-16: warning: useless associativity for FUNC_CALL, use %precedence [-Wprecedence]
input.y:21.8-14: warning: useless associativity for YNUMBER, use %precedence [-Wprecedence]
input.y:21.16-22: warning: useless associativity for YSTRING, use %precedence [-Wprecedence]
@@ -1404,7 +1424,29 @@ dnl INPUT
dnl BISON-STDERR
[AT_COND_CASE([[canonical LR]],
[[input.y: warning: 1876 shift/reduce conflicts [-Wconflicts-sr]
[[input.y:128.12: warning: empty rule without %empty [-Wempty-rule]
input.y:137.10: warning: empty rule without %empty [-Wempty-rule]
input.y:142.8: warning: empty rule without %empty [-Wempty-rule]
input.y:161.15: warning: empty rule without %empty [-Wempty-rule]
input.y:179.17: warning: empty rule without %empty [-Wempty-rule]
input.y:205.16: warning: empty rule without %empty [-Wempty-rule]
input.y:213.9: warning: empty rule without %empty [-Wempty-rule]
input.y:225.6: warning: empty rule without %empty [-Wempty-rule]
input.y:292.18: warning: empty rule without %empty [-Wempty-rule]
input.y:294.19: warning: empty rule without %empty [-Wempty-rule]
input.y:367.16: warning: empty rule without %empty [-Wempty-rule]
input.y:373.11: warning: empty rule without %empty [-Wempty-rule]
input.y:387.15: warning: empty rule without %empty [-Wempty-rule]
input.y:401.18: warning: empty rule without %empty [-Wempty-rule]
input.y:413.15: warning: empty rule without %empty [-Wempty-rule]
input.y:443.15: warning: empty rule without %empty [-Wempty-rule]
input.y:471.15: warning: empty rule without %empty [-Wempty-rule]
input.y:474.15: warning: empty rule without %empty [-Wempty-rule]
input.y:489.15: warning: empty rule without %empty [-Wempty-rule]
input.y:506.14: warning: empty rule without %empty [-Wempty-rule]
input.y:587.9: warning: empty rule without %empty [-Wempty-rule]
input.y:591.14: warning: empty rule without %empty [-Wempty-rule]
input.y: warning: 1876 shift/reduce conflicts [-Wconflicts-sr]
input.y: warning: 144 reduce/reduce conflicts [-Wconflicts-rr]
input.y:32.9-12: warning: useless associativity for HQUA, use %precedence [-Wprecedence]
input.y:53.8-14: warning: useless associativity for HASSIGN, use %precedence [-Wprecedence]
@@ -1412,7 +1454,29 @@ input.y:54.9-15: warning: useless associativity for HORELSE, use %precedence [-W
input.y:55.9-16: warning: useless associativity for HANDTHEN, use %precedence [-Wprecedence]
input.y:61.9-12: warning: useless associativity for HNOT, use %precedence [-Wprecedence]
input.y:68.7-11: warning: useless associativity for UNEAR, use %precedence [-Wprecedence]]],
[[input.y: warning: 78 shift/reduce conflicts [-Wconflicts-sr]
[[input.y:128.12: warning: empty rule without %empty [-Wempty-rule]
input.y:137.10: warning: empty rule without %empty [-Wempty-rule]
input.y:142.8: warning: empty rule without %empty [-Wempty-rule]
input.y:161.15: warning: empty rule without %empty [-Wempty-rule]
input.y:179.17: warning: empty rule without %empty [-Wempty-rule]
input.y:205.16: warning: empty rule without %empty [-Wempty-rule]
input.y:213.9: warning: empty rule without %empty [-Wempty-rule]
input.y:225.6: warning: empty rule without %empty [-Wempty-rule]
input.y:292.18: warning: empty rule without %empty [-Wempty-rule]
input.y:294.19: warning: empty rule without %empty [-Wempty-rule]
input.y:367.16: warning: empty rule without %empty [-Wempty-rule]
input.y:373.11: warning: empty rule without %empty [-Wempty-rule]
input.y:387.15: warning: empty rule without %empty [-Wempty-rule]
input.y:401.18: warning: empty rule without %empty [-Wempty-rule]
input.y:413.15: warning: empty rule without %empty [-Wempty-rule]
input.y:443.15: warning: empty rule without %empty [-Wempty-rule]
input.y:471.15: warning: empty rule without %empty [-Wempty-rule]
input.y:474.15: warning: empty rule without %empty [-Wempty-rule]
input.y:489.15: warning: empty rule without %empty [-Wempty-rule]
input.y:506.14: warning: empty rule without %empty [-Wempty-rule]
input.y:587.9: warning: empty rule without %empty [-Wempty-rule]
input.y:591.14: warning: empty rule without %empty [-Wempty-rule]
input.y: warning: 78 shift/reduce conflicts [-Wconflicts-sr]
input.y: warning: 10 reduce/reduce conflicts [-Wconflicts-rr]
input.y:32.9-12: warning: useless associativity for HQUA, use %precedence [-Wprecedence]
input.y:53.8-14: warning: useless associativity for HASSIGN, use %precedence [-Wprecedence]
@@ -2001,7 +2065,12 @@ dnl without being followed by "of".)
[[VARIABLE, '=', LABEL, LEFT, DOT_X]],
dnl BISON-STDERR
[[input.y:471.11-48: warning: rule useless in parser due to conflicts [-Wother]
[[input.y:202.19: warning: empty rule without %empty [-Wempty-rule]
input.y:270.6: warning: empty rule without %empty [-Wempty-rule]
input.y:292.12: warning: empty rule without %empty [-Wempty-rule]
input.y:309.17: warning: empty rule without %empty [-Wempty-rule]
input.y:382.13: warning: empty rule without %empty [-Wempty-rule]
input.y:471.11-48: warning: rule useless in parser due to conflicts [-Wother]
input.y:19.8-12: warning: useless associativity for LABEL, use %precedence [-Wprecedence]
input.y:20.8-15: warning: useless associativity for VARIABLE, use %precedence [-Wprecedence]
input.y:21.8-13: warning: useless associativity for NUMBER, use %precedence [-Wprecedence]