X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/e8832397ea06de8049828011aff948b5302ffe66..a1d1ab50a00a4d28d6ba7b227ddc6628d5734ce3:/tests/conflicts.at diff --git a/tests/conflicts.at b/tests/conflicts.at index d0da937b..a46acc5a 100644 --- a/tests/conflicts.at +++ b/tests/conflicts.at @@ -1,20 +1,20 @@ # Exercising Bison on conflicts. -*- Autotest -*- -# Copyright (C) 2002 Free Software Foundation, Inc. -# This program is free software; you can redistribute it and/or modify -# it under the terms of the GNU General Public License as published by -# the Free Software Foundation; either version 2, or (at your option) -# any later version. +# Copyright (C) 2002-2005, 2007, 2009-2012 Free Software Foundation, +# Inc. +# This program is free software: you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation, either version 3 of the License, or +# (at your option) any later version. +# # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. - +# # You should have received a copy of the GNU General Public License -# along with this program; if not, write to the Free Software -# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA -# 02111-1307, USA. +# along with this program. If not, see . AT_BANNER([[Conflicts.]]) @@ -37,8 +37,8 @@ exp: e 'e'; e: 'e' | /* Nothing. */; ]]) -AT_CHECK([bison input.y -o input.c], 0, [], -[[input.y:4.8: warning: rule never reduced because of conflicts: e: /* empty */ +AT_BISON_CHECK([-o input.c input.y], 0, [], +[[input.y:4.9: warning: rule useless in parser due to conflicts: e: /* empty */ ]]) AT_CLEANUP @@ -50,37 +50,26 @@ AT_CLEANUP AT_SETUP([%nonassoc and eof]) -AT_DATA([input.y], +AT_BISON_OPTION_PUSHDEFS +AT_DATA_GRAMMAR([input.y], [[ %{ -#include -/* We don't need a perfect malloc for these tests. */ -#undef malloc #include - -#if STDC_HEADERS -# include -#endif +#include +#include +#include #define YYERROR_VERBOSE 1 -static void -yyerror (const char *msg) -{ - fprintf (stderr, "%s\n", msg); - exit (1); -} - +]AT_YYERROR_DEFINE[ /* The current argument. */ -static const char *input = NULL; +static const char *input; static int yylex (void) { - /* No token stands for end of file. */ - if (input && *input) - return *input++; - else - return 0; + static size_t toknum; + assert (toknum <= strlen (input)); + return input[toknum++]; } %} @@ -96,37 +85,454 @@ expr: expr '<' expr int main (int argc, const char *argv[]) { - if (argc > 1) - input = argv[1]; + input = argc <= 1 ? "" : argv[1]; return yyparse (); } ]]) +AT_BISON_OPTION_POPDEFS -# Specify the output files to avoid problems on different file systems. -AT_CHECK([bison input.y -o input.c]) +m4_pushdef([AT_NONASSOC_AND_EOF_CHECK], +[AT_BISON_CHECK([$1[ -o input.c input.y]]) AT_COMPILE([input]) +m4_pushdef([AT_EXPECTING], [m4_if($2, [correct], [[, expecting $end]])]) + AT_PARSER_CHECK([./input '0<0']) -# FIXME: This is an actual bug, but a new one, in the sense that -# no one has ever spotted it! The messages are *wrong*: there should -# be nothing there, it should be expected eof. AT_PARSER_CHECK([./input '0<0<0'], [1], [], - [parse error, unexpected '<', expecting '<' or '>' + [syntax error, unexpected '<'AT_EXPECTING ]) AT_PARSER_CHECK([./input '0>0']) AT_PARSER_CHECK([./input '0>0>0'], [1], [], - [parse error, unexpected '>', expecting '<' or '>' + [syntax error, unexpected '>'AT_EXPECTING ]) AT_PARSER_CHECK([./input '0<0>0'], [1], [], - [parse error, unexpected '>', expecting '<' or '>' + [syntax error, unexpected '>'AT_EXPECTING +]) + +m4_popdef([AT_EXPECTING])]) + +# Expected token list is missing. +AT_NONASSOC_AND_EOF_CHECK([], [[incorrect]]) + +# We must disable default reductions in inconsistent states in order to +# have an explicit list of all expected tokens. +AT_NONASSOC_AND_EOF_CHECK([[-Dlr.default-reductions=consistent]], + [[correct]]) + +# lr.default-reductions=consistent happens to work for this test case. +# However, for other grammars, lookahead sets can be merged for +# different left contexts, so it is still possible to have an incorrect +# expected list. Canonical LR is almost a general solution (that is, it +# can fail only when %nonassoc is used), so make sure it gives the same +# result as above. +AT_NONASSOC_AND_EOF_CHECK([[-Dlr.type=canonical-lr]], [[correct]]) + +# parse.lac=full is a completely general solution that does not require +# any of the above sacrifices. Of course, it does not extend the +# language-recognition power of LALR to (IE)LR, but it does ensure that +# the reported list of expected tokens matches what the given parser +# would have accepted in place of the unexpected token. +AT_NONASSOC_AND_EOF_CHECK([[-Dparse.lac=full]], [[correct]]) + +m4_popdef([AT_NONASSOC_AND_EOF_CHECK]) + +AT_CLEANUP + + + +## -------------------------------------- ## +## %error-verbose and consistent errors. ## +## -------------------------------------- ## + +AT_SETUP([[%error-verbose and consistent errors]]) + +m4_pushdef([AT_CONSISTENT_ERRORS_CHECK], [ + +AT_BISON_OPTION_PUSHDEFS([$1]) + +m4_pushdef([AT_YYLEX_PROTOTYPE], +[AT_SKEL_CC_IF([[int yylex (yy::parser::semantic_type *lvalp)]], + [[int yylex (YYSTYPE *lvalp)]])]) + +AT_SKEL_JAVA_IF([AT_DATA], [AT_DATA_GRAMMAR])([input.y], +[AT_SKEL_JAVA_IF([[ + +%code imports { + import java.io.IOException; +}]], [[ + +%code {]AT_SKEL_CC_IF([[ + #include + #include ]], [[ + #include + #include + ]AT_YYERROR_DECLARE])[ + ]AT_YYLEX_PROTOTYPE[; + #define USE(Var) +} + +]AT_SKEL_CC_IF([[%defines]], [[%define api.pure]])])[ + +]$1[ + +%error-verbose + +%% + +]$2[ + +]AT_SKEL_JAVA_IF([[%code lexer {]], [[%%]])[ + +/*--------. +| yylex. | +`--------*/]AT_SKEL_JAVA_IF([[ + +public String input = "]$3["; +public int index = 0; +public int yylex () +{ + if (index < input.length ()) + return input.charAt (index++); + else + return 0; +} +public Object getLVal () +{ + return new Integer(1); +}]], [[ + +]AT_YYLEX_PROTOTYPE[ +{ + static char const *input = "]$3["; + *lvalp = 1; + return *input++; +}]])[ +]AT_YYERROR_DEFINE[ +]AT_SKEL_JAVA_IF([[ +}; + +%%]])[ + +/*-------. +| main. | +`-------*/]AT_SKEL_JAVA_IF([[ + +class input +{ + public static void main (String args[]) throws IOException + { + YYParser p = new YYParser (); + p.parse (); + } +}]], [AT_SKEL_CC_IF([[ + +int +main (void) +{ + yy::parser parser; + return parser.parse (); +}]], [[ + +int +main (void) +{ + return yyparse (); +}]])])[ +]]) + +AT_FULL_COMPILE([[input]]) + +m4_pushdef([AT_EXPECTING], [m4_if($5, [ab], [[, expecting 'a' or 'b']], + $5, [a], [[, expecting 'a']], + $5, [b], [[, expecting 'b']])]) + +AT_SKEL_JAVA_IF([AT_JAVA_PARSER_CHECK([[input]], [[0]]], + [AT_PARSER_CHECK([[./input]], [[1]]]), +[[]], +[[syntax error, unexpected ]$4[]AT_EXPECTING[ +]]) + +m4_popdef([AT_EXPECTING]) +m4_popdef([AT_YYLEX_PROTOTYPE]) +AT_BISON_OPTION_POPDEFS + ]) +m4_pushdef([AT_PREVIOUS_STATE_GRAMMAR], +[[%nonassoc 'a'; + +start: consistent-error-on-a-a 'a' ; + +consistent-error-on-a-a: + 'a' default-reduction + | 'a' default-reduction 'a' + | 'a' shift + ; + +default-reduction: /*empty*/ ; +shift: 'b' ; + +// Provide another context in which all rules are useful so that this +// test case looks a little more realistic. +start: 'b' consistent-error-on-a-a 'c' ; +]]) + +m4_pushdef([AT_PREVIOUS_STATE_INPUT], [[a]]) + +# Unfortunately, no expected tokens are reported even though 'b' can be +# accepted. Nevertheless, the main point of this test is to make sure +# that at least the unexpected token is reported. In a previous version +# of Bison, it wasn't reported because the error is detected in a +# consistent state with an error action, and that case always triggered +# the simple "syntax error" message. +# +# The point isn't to test IELR here, but state merging happens to +# complicate this example. +AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr]], + [AT_PREVIOUS_STATE_GRAMMAR], + [AT_PREVIOUS_STATE_INPUT], + [[$end]], [[none]]) +AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr + %glr-parser]], + [AT_PREVIOUS_STATE_GRAMMAR], + [AT_PREVIOUS_STATE_INPUT], + [[$end]], [[none]]) +AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr + %language "c++"]], + [AT_PREVIOUS_STATE_GRAMMAR], + [AT_PREVIOUS_STATE_INPUT], + [[$end]], [[none]]) +AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr + %language "java"]], + [AT_PREVIOUS_STATE_GRAMMAR], + [AT_PREVIOUS_STATE_INPUT], + [[end of input]], [[none]]) + +# Even canonical LR doesn't foresee the error for 'a'! +AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr + %define lr.default-reductions consistent]], + [AT_PREVIOUS_STATE_GRAMMAR], + [AT_PREVIOUS_STATE_INPUT], + [[$end]], [[ab]]) +AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr + %define lr.default-reductions accepting]], + [AT_PREVIOUS_STATE_GRAMMAR], + [AT_PREVIOUS_STATE_INPUT], + [[$end]], [[ab]]) +AT_CONSISTENT_ERRORS_CHECK([[%define lr.type canonical-lr]], + [AT_PREVIOUS_STATE_GRAMMAR], + [AT_PREVIOUS_STATE_INPUT], + [[$end]], [[ab]]) + +# Only LAC gets it right. +AT_CONSISTENT_ERRORS_CHECK([[%define lr.type canonical-lr + %define parse.lac full]], + [AT_PREVIOUS_STATE_GRAMMAR], + [AT_PREVIOUS_STATE_INPUT], + [[$end]], [[b]]) +AT_CONSISTENT_ERRORS_CHECK([[%define lr.type ielr + %define parse.lac full]], + [AT_PREVIOUS_STATE_GRAMMAR], + [AT_PREVIOUS_STATE_INPUT], + [[$end]], [[b]]) + +m4_popdef([AT_PREVIOUS_STATE_GRAMMAR]) +m4_popdef([AT_PREVIOUS_STATE_INPUT]) + +m4_pushdef([AT_USER_ACTION_GRAMMAR], +[[%nonassoc 'a'; + +// If $$ = 0 here, then we know that the 'a' destructor is being invoked +// incorrectly for the 'b' set in the semantic action below. All 'a' +// tokens are returned by yylex, which sets $$ = 1. +%destructor { + if (!$$) + fprintf (stderr, "Wrong destructor.\n"); +} 'a'; + +// Rather than depend on an inconsistent state to induce reading a +// lookahead as in the previous grammar, just assign the lookahead in a +// semantic action. That lookahead isn't needed before either error +// action is encountered. In a previous version of Bison, this was a +// problem as it meant yychar was not translated into yytoken before +// either error action. The second error action thus invoked a +// destructor that it selected according to the incorrect yytoken. The +// first error action would have reported an incorrect unexpected token +// except that, due to the bug described in the previous grammar, the +// unexpected token was not reported at all. +start: error-reduce consistent-error 'a' { USE ($][3); } ; + +error-reduce: + 'a' 'a' consistent-reduction consistent-error 'a' + { USE (($][1, $][2, $][5)); } +| 'a' error + { USE ($][1); } +; + +consistent-reduction: /*empty*/ { + assert (yychar == ]AT_SKEL_CC_IF([[yyempty_]], [[YYEMPTY]])[); + yylval = 0; + yychar = 'b'; +} ; + +consistent-error: + 'a' { USE ($][1); } +| /*empty*/ %prec 'a' +; + +// Provide another context in which all rules are useful so that this +// test case looks a little more realistic. +start: 'b' consistent-error 'b' ; +]]) +m4_pushdef([AT_USER_ACTION_INPUT], [[aa]]) + +AT_CONSISTENT_ERRORS_CHECK([[]], + [AT_USER_ACTION_GRAMMAR], + [AT_USER_ACTION_INPUT], + [['b']], [[none]]) +AT_CONSISTENT_ERRORS_CHECK([[%glr-parser]], + [AT_USER_ACTION_GRAMMAR], + [AT_USER_ACTION_INPUT], + [['b']], [[none]]) +AT_CONSISTENT_ERRORS_CHECK([[%language "c++"]], + [AT_USER_ACTION_GRAMMAR], + [AT_USER_ACTION_INPUT], + [['b']], [[none]]) +# No Java test because yychar cannot be manipulated by users. + +AT_CONSISTENT_ERRORS_CHECK([[%define lr.default-reductions consistent]], + [AT_USER_ACTION_GRAMMAR], + [AT_USER_ACTION_INPUT], + [['b']], [[none]]) + +# Canonical LR doesn't foresee the error for 'a'! +AT_CONSISTENT_ERRORS_CHECK([[%define lr.default-reductions accepting]], + [AT_USER_ACTION_GRAMMAR], + [AT_USER_ACTION_INPUT], + [[$end]], [[a]]) +AT_CONSISTENT_ERRORS_CHECK([[%define lr.type canonical-lr]], + [AT_USER_ACTION_GRAMMAR], + [AT_USER_ACTION_INPUT], + [[$end]], [[a]]) + +AT_CONSISTENT_ERRORS_CHECK([[%define parse.lac full]], + [AT_USER_ACTION_GRAMMAR], + [AT_USER_ACTION_INPUT], + [['b']], [[none]]) +AT_CONSISTENT_ERRORS_CHECK([[%define parse.lac full + %define lr.default-reductions accepting]], + [AT_USER_ACTION_GRAMMAR], + [AT_USER_ACTION_INPUT], + [[$end]], [[none]]) + +m4_popdef([AT_USER_ACTION_GRAMMAR]) +m4_popdef([AT_USER_ACTION_INPUT]) + +m4_popdef([AT_CONSISTENT_ERRORS_CHECK]) + AT_CLEANUP +## ------------------------------------------------------- ## +## LAC: %nonassoc requires splitting canonical LR states. ## +## ------------------------------------------------------- ## + +# This test case demonstrates that, when %nonassoc is used, canonical +# LR(1) parser table construction followed by conflict resolution +# without further state splitting is not always sufficient to produce a +# parser that can detect all syntax errors as soon as possible on one +# token of lookahead. However, LAC solves the problem completely even +# with minimal LR parser tables. + +AT_SETUP([[LAC: %nonassoc requires splitting canonical LR states]]) +AT_BISON_OPTION_PUSHDEFS +AT_DATA_GRAMMAR([[input.y]], +[[%code { + #include + ]AT_YYERROR_DECLARE[ + ]AT_YYLEX_DECLARE[ +} + +%error-verbose +%nonassoc 'a' + +%% + +start: + 'a' problem 'a' // First context. +| 'b' problem 'b' // Second context. +| 'c' reduce-nonassoc // Just makes reduce-nonassoc useful. +; + +problem: + look reduce-nonassoc +| look 'a' +| look 'b' +; + +// For the state reached after shifting the 'a' in these productions, +// lookahead sets are the same in both the first and second contexts. +// Thus, canonical LR reuses the same state for both contexts. However, +// the lookahead 'a' for the reduction "look: 'a'" later becomes an +// error action only in the first context. In order to immediately +// detect the syntax error on 'a' here for only the first context, this +// canonical LR state would have to be split into two states, and the +// 'a' lookahead would have to be removed from only one of the states. +look: + 'a' // Reduction lookahead set is always ['a', 'b']. +| 'a' 'b' +| 'a' 'c' // 'c' is forgotten as an expected token. +; + +reduce-nonassoc: %prec 'a'; + +%% +]AT_YYERROR_DEFINE[ +]AT_YYLEX_DEFINE(["aaa"])[ + +int +main (void) +{ + return yyparse (); +} +]]) +AT_BISON_OPTION_POPDEFS + +# Show canonical LR's failure. +AT_BISON_CHECK([[-Dlr.type=canonical-lr -o input.c input.y]], + [[0]], [[]], +[[input.y: conflicts: 2 shift/reduce +]]) +AT_COMPILE([[input]]) +AT_PARSER_CHECK([[./input]], [[1]], [[]], +[[syntax error, unexpected 'a', expecting 'b' +]]) + +# It's corrected by LAC. +AT_BISON_CHECK([[-Dlr.type=canonical-lr -Dparse.lac=full \ + -o input.c input.y]], [[0]], [[]], +[[input.y: conflicts: 2 shift/reduce +]]) +AT_COMPILE([[input]]) +AT_PARSER_CHECK([[./input]], [[1]], [[]], +[[syntax error, unexpected 'a', expecting 'b' or 'c' +]]) + +# IELR is sufficient when LAC is used. +AT_BISON_CHECK([[-Dlr.type=ielr -Dparse.lac=full -o input.c input.y]], + [[0]], [[]], +[[input.y: conflicts: 2 shift/reduce +]]) +AT_COMPILE([[input]]) +AT_PARSER_CHECK([[./input]], [[1]], [[]], +[[syntax error, unexpected 'a', expecting 'b' or 'c' +]]) + +AT_CLEANUP + ## ------------------------- ## ## Unresolved SR Conflicts. ## ## ------------------------- ## @@ -141,13 +547,13 @@ AT_DATA([input.y], exp: exp OP exp | NUM; ]]) -AT_CHECK([bison input.y -o input.c --report=all], 0, [], -[input.y contains 1 shift/reduce conflict. +AT_BISON_CHECK([-o input.c --report=all input.y], 0, [], +[input.y: conflicts: 1 shift/reduce ]) # Check the contents of the report. AT_CHECK([cat input.output], [], -[[State 5 contains 1 shift/reduce conflict. +[[State 5 conflicts: 1 shift/reduce Grammar @@ -221,7 +627,7 @@ state 4 state 5 - 1 exp: exp . OP exp [$end, OP] + 1 exp: exp . OP exp 1 | exp OP exp . [$end, OP] OP shift, and go to state 4 @@ -249,7 +655,7 @@ AT_DATA([input.y], exp: exp OP exp | NUM; ]]) -AT_CHECK([bison input.y -o input.c --report=all]) +AT_BISON_CHECK([-o input.c --report=all input.y]) # Check the contents of the report. AT_CHECK([cat input.output], [], @@ -324,10 +730,11 @@ state 4 state 5 - 1 exp: exp . OP exp [$end, OP] + 1 exp: exp . OP exp 1 | exp OP exp . [$end, OP] $default reduce using rule 1 (exp) + Conflict between rule 1 and token OP resolved as reduce (%left OP). ]]) @@ -370,14 +777,19 @@ id : '0'; %% ]]) -AT_CHECK([bison input.y -o input.c --report=all], 0, [], -[[input.y contains 1 reduce/reduce conflict. -input.y:4.4-8: warning: rule never reduced because of conflicts: id: '0' +AT_BISON_CHECK([-o input.c --report=all input.y], 0, [], +[[input.y: conflicts: 1 reduce/reduce +input.y:4.6-8: warning: rule useless in parser due to conflicts: id: '0' ]]) # Check the contents of the report. AT_CHECK([cat input.output], [], -[[State 1 contains 1 reduce/reduce conflict. +[[Rules useless in parser due to conflicts + + 4 id: '0' + + +State 1 conflicts: 1 reduce/reduce Grammar @@ -482,9 +894,9 @@ AT_DATA([input.y], exp: exp OP exp | NUM; ]]) -AT_CHECK([bison input.y -o input.c], 1, [], -[input.y contains 1 shift/reduce conflict. -expected 0 shift/reduce conflicts +AT_BISON_CHECK([-o input.c input.y], 1, [], +[input.y: conflicts: 1 shift/reduce +input.y: expected 0 shift/reduce conflicts ]) AT_CLEANUP @@ -502,7 +914,7 @@ AT_DATA([input.y], exp: exp OP exp | NUM; ]]) -AT_CHECK([bison input.y -o input.c]) +AT_BISON_CHECK([-o input.c input.y]) AT_CLEANUP @@ -519,8 +931,580 @@ AT_DATA([input.y], exp: exp OP exp | NUM; ]]) -AT_CHECK([bison input.y -o input.c], 1, [], -[input.y contains 1 shift/reduce conflict. -expected 2 shift/reduce conflicts +AT_BISON_CHECK([-o input.c input.y], 1, [], +[input.y: conflicts: 1 shift/reduce +input.y: expected 2 shift/reduce conflicts ]) AT_CLEANUP + + +## ------------------------------- ## +## %expect with reduce conflicts. ## +## ------------------------------- ## + +AT_SETUP([%expect with reduce conflicts]) + +AT_DATA([input.y], +[[%expect 0 +%% +program: a 'a' | a a; +a: 'a'; +]]) + +AT_BISON_CHECK([-o input.c input.y], 1, [], +[input.y: conflicts: 1 reduce/reduce +input.y: expected 0 reduce/reduce conflicts +]) +AT_CLEANUP + + +## ------------------------- ## +## %prec with user strings. ## +## ------------------------- ## + +AT_SETUP([%prec with user string]) + +AT_DATA([[input.y]], +[[%% +exp: + "foo" %prec "foo" +; +]]) + +AT_BISON_CHECK([-o input.c input.y]) +AT_CLEANUP + + +## -------------------------------- ## +## %no-default-prec without %prec. ## +## -------------------------------- ## + +AT_SETUP([%no-default-prec without %prec]) + +AT_DATA([[input.y]], +[[%left '+' +%left '*' + +%% + +%no-default-prec; + +e: e '+' e + | e '*' e + | '0' + ; +]]) + +AT_BISON_CHECK([-o input.c input.y], 0, [], +[[input.y: conflicts: 4 shift/reduce +]]) +AT_CLEANUP + + +## ----------------------------- ## +## %no-default-prec with %prec. ## +## ----------------------------- ## + +AT_SETUP([%no-default-prec with %prec]) + +AT_DATA([[input.y]], +[[%left '+' +%left '*' + +%% + +%no-default-prec; + +e: e '+' e %prec '+' + | e '*' e %prec '*' + | '0' + ; +]]) + +AT_BISON_CHECK([-o input.c input.y]) +AT_CLEANUP + + +## --------------- ## +## %default-prec. ## +## --------------- ## + +AT_SETUP([%default-prec]) + +AT_DATA([[input.y]], +[[%left '+' +%left '*' + +%% + +%default-prec; + +e: e '+' e + | e '*' e + | '0' + ; +]]) + +AT_BISON_CHECK([-o input.c input.y]) +AT_CLEANUP + + +## ---------------------------------------------- ## +## Unreachable States After Conflict Resolution. ## +## ---------------------------------------------- ## + +AT_SETUP([[Unreachable States After Conflict Resolution]]) + +# If conflict resolution makes states unreachable, remove those states, report +# rules that are then unused, and don't report conflicts in those states. Test +# what happens when a nonterminal becomes useless as a result of state removal +# since that causes lalr.o's goto map to be rewritten. + +AT_DATA([[input.y]], +[[%output "input.c" +%left 'a' + +%% + +start: resolved_conflict 'a' reported_conflicts 'a' ; + +/* S/R conflict resolved as reduce, so the state with item + * (resolved_conflict: 'a' . unreachable1) and all it transition successors are + * unreachable, and the associated production is useless. */ +resolved_conflict: + 'a' unreachable1 + | %prec 'a' + ; + +/* S/R conflict that need not be reported since it is unreachable because of + * the previous conflict resolution. Nonterminal unreachable1 and all its + * productions are useless. */ +unreachable1: + 'a' unreachable2 + | + ; + +/* Likewise for a R/R conflict and nonterminal unreachable2. */ +unreachable2: | ; + +/* Make sure remaining S/R and R/R conflicts are still reported correctly even + * when their states are renumbered due to state removal. */ +reported_conflicts: + 'a' + | 'a' + | + ; + +]]) + +AT_BISON_CHECK([[--report=all input.y]], 0, [], +[[input.y: conflicts: 1 shift/reduce, 1 reduce/reduce +input.y:12.5-20: warning: rule useless in parser due to conflicts: resolved_conflict: 'a' unreachable1 +input.y:20.5-20: warning: rule useless in parser due to conflicts: unreachable1: 'a' unreachable2 +input.y:21.4: warning: rule useless in parser due to conflicts: unreachable1: /* empty */ +input.y:25.13: warning: rule useless in parser due to conflicts: unreachable2: /* empty */ +input.y:25.16: warning: rule useless in parser due to conflicts: unreachable2: /* empty */ +input.y:31.5-7: warning: rule useless in parser due to conflicts: reported_conflicts: 'a' +input.y:32.4: warning: rule useless in parser due to conflicts: reported_conflicts: /* empty */ +]]) + +AT_CHECK([[cat input.output]], 0, +[[Rules useless in parser due to conflicts + + 2 resolved_conflict: 'a' unreachable1 + + 4 unreachable1: 'a' unreachable2 + 5 | /* empty */ + + 6 unreachable2: /* empty */ + 7 | /* empty */ + + 9 reported_conflicts: 'a' + 10 | /* empty */ + + +State 4 conflicts: 1 shift/reduce +State 5 conflicts: 1 reduce/reduce + + +Grammar + + 0 $accept: start $end + + 1 start: resolved_conflict 'a' reported_conflicts 'a' + + 2 resolved_conflict: 'a' unreachable1 + 3 | /* empty */ + + 4 unreachable1: 'a' unreachable2 + 5 | /* empty */ + + 6 unreachable2: /* empty */ + 7 | /* empty */ + + 8 reported_conflicts: 'a' + 9 | 'a' + 10 | /* empty */ + + +Terminals, with rules where they appear + +$end (0) 0 +'a' (97) 1 2 4 8 9 +error (256) + + +Nonterminals, with rules where they appear + +$accept (4) + on left: 0 +start (5) + on left: 1, on right: 0 +resolved_conflict (6) + on left: 2 3, on right: 1 +unreachable1 (7) + on left: 4 5, on right: 2 +unreachable2 (8) + on left: 6 7, on right: 4 +reported_conflicts (9) + on left: 8 9 10, on right: 1 + + +state 0 + + 0 $accept: . start $end + 1 start: . resolved_conflict 'a' reported_conflicts 'a' + 2 resolved_conflict: . 'a' unreachable1 + 3 | . ['a'] + + $default reduce using rule 3 (resolved_conflict) + + start go to state 1 + resolved_conflict go to state 2 + + Conflict between rule 3 and token 'a' resolved as reduce (%left 'a'). + + +state 1 + + 0 $accept: start . $end + + $end shift, and go to state 3 + + +state 2 + + 1 start: resolved_conflict . 'a' reported_conflicts 'a' + + 'a' shift, and go to state 4 + + +state 3 + + 0 $accept: start $end . + + $default accept + + +state 4 + + 1 start: resolved_conflict 'a' . reported_conflicts 'a' + 8 reported_conflicts: . 'a' + 9 | . 'a' + 10 | . ['a'] + + 'a' shift, and go to state 5 + + 'a' [reduce using rule 10 (reported_conflicts)] + + reported_conflicts go to state 6 + + +state 5 + + 8 reported_conflicts: 'a' . ['a'] + 9 | 'a' . ['a'] + + 'a' reduce using rule 8 (reported_conflicts) + 'a' [reduce using rule 9 (reported_conflicts)] + $default reduce using rule 8 (reported_conflicts) + + +state 6 + + 1 start: resolved_conflict 'a' reported_conflicts . 'a' + + 'a' shift, and go to state 7 + + +state 7 + + 1 start: resolved_conflict 'a' reported_conflicts 'a' . + + $default reduce using rule 1 (start) +]]) + +AT_DATA([[input-keep.y]], +[[%define lr.keep-unreachable-states +]]) +AT_CHECK([[cat input.y >> input-keep.y]]) + +AT_BISON_CHECK([[input-keep.y]], 0, [], +[[input-keep.y: conflicts: 2 shift/reduce, 2 reduce/reduce +input-keep.y:22.4: warning: rule useless in parser due to conflicts: unreachable1: /* empty */ +input-keep.y:26.16: warning: rule useless in parser due to conflicts: unreachable2: /* empty */ +input-keep.y:32.5-7: warning: rule useless in parser due to conflicts: reported_conflicts: 'a' +input-keep.y:33.4: warning: rule useless in parser due to conflicts: reported_conflicts: /* empty */ +]]) + +AT_CLEANUP + + +## ------------------------------------------------------------ ## +## Solved conflicts report for multiple reductions in a state. ## +## ------------------------------------------------------------ ## + +AT_SETUP([[Solved conflicts report for multiple reductions in a state]]) + +# Used to lose earlier solved conflict messages even within a single S/R/R. + +AT_DATA([[input.y]], +[[%left 'a' +%right 'b' +%right 'c' +%right 'd' +%% +start: + 'a' + | empty_a 'a' + | 'b' + | empty_b 'b' + | 'c' + | empty_c1 'c' + | empty_c2 'c' + | empty_c3 'c' + ; +empty_a: %prec 'a' ; +empty_b: %prec 'b' ; +empty_c1: %prec 'c' ; +empty_c2: %prec 'c' ; +empty_c3: %prec 'd' ; +]]) +AT_BISON_CHECK([[--report=all -o input.c input.y]], 0, [], [ignore]) +AT_CHECK([[cat input.output | sed -n '/^state 0$/,/^state 1$/p']], 0, +[[state 0 + + 0 $accept: . start $end + 1 start: . 'a' + 2 | . empty_a 'a' + 3 | . 'b' + 4 | . empty_b 'b' + 5 | . 'c' + 6 | . empty_c1 'c' + 7 | . empty_c2 'c' + 8 | . empty_c3 'c' + 9 empty_a: . ['a'] + 10 empty_b: . [] + 11 empty_c1: . [] + 12 empty_c2: . [] + 13 empty_c3: . ['c'] + + 'b' shift, and go to state 1 + + 'c' reduce using rule 13 (empty_c3) + $default reduce using rule 9 (empty_a) + + start go to state 2 + empty_a go to state 3 + empty_b go to state 4 + empty_c1 go to state 5 + empty_c2 go to state 6 + empty_c3 go to state 7 + + Conflict between rule 9 and token 'a' resolved as reduce (%left 'a'). + Conflict between rule 10 and token 'b' resolved as shift (%right 'b'). + Conflict between rule 11 and token 'c' resolved as shift (%right 'c'). + Conflict between rule 12 and token 'c' resolved as shift (%right 'c'). + Conflict between rule 13 and token 'c' resolved as reduce ('c' < 'd'). + + +state 1 +]]) + +AT_CLEANUP + + +## ------------------------------------------------------------ ## +## %nonassoc error actions for multiple reductions in a state. ## +## ------------------------------------------------------------ ## + +# Used to abort when trying to resolve conflicts as %nonassoc error actions for +# multiple reductions in a state. + +# For a %nonassoc error action token, used to print the first remaining +# reduction on that token without brackets. + +AT_SETUP([[%nonassoc error actions for multiple reductions in a state]]) + +AT_DATA([[input.y]], +[[%nonassoc 'a' 'b' 'c' +%% +start: + 'a' + | empty_a 'a' + | 'b' + | empty_b 'b' + | 'c' + | empty_c1 'c' + | empty_c2 'c' + | empty_c3 'c' + ; +empty_a: %prec 'a' ; +empty_b: %prec 'b' ; +empty_c1: %prec 'c' ; +empty_c2: %prec 'c' ; +empty_c3: %prec 'c' ; +]]) + +AT_BISON_CHECK([[--report=all -o input.c input.y]], 0, [], [ignore]) +AT_CHECK([[cat input.output | sed -n '/^state 0$/,/^state 1$/p']], 0, +[[state 0 + + 0 $accept: . start $end + 1 start: . 'a' + 2 | . empty_a 'a' + 3 | . 'b' + 4 | . empty_b 'b' + 5 | . 'c' + 6 | . empty_c1 'c' + 7 | . empty_c2 'c' + 8 | . empty_c3 'c' + 9 empty_a: . [] + 10 empty_b: . [] + 11 empty_c1: . [] + 12 empty_c2: . ['c'] + 13 empty_c3: . ['c'] + + 'a' error (nonassociative) + 'b' error (nonassociative) + 'c' error (nonassociative) + + 'c' [reduce using rule 12 (empty_c2)] + 'c' [reduce using rule 13 (empty_c3)] + + start go to state 1 + empty_a go to state 2 + empty_b go to state 3 + empty_c1 go to state 4 + empty_c2 go to state 5 + empty_c3 go to state 6 + + Conflict between rule 9 and token 'a' resolved as an error (%nonassoc 'a'). + Conflict between rule 10 and token 'b' resolved as an error (%nonassoc 'b'). + Conflict between rule 11 and token 'c' resolved as an error (%nonassoc 'c'). + + +state 1 +]]) +AT_CLEANUP + + +## --------------------------------- ## +## -W versus %expect and %expect-rr ## +## --------------------------------- ## + +AT_SETUP([[-W versus %expect and %expect-rr]]) + +AT_DATA([[sr-rr.y]], +[[%glr-parser +%% +start: 'a' | A 'a' | B 'a' ; +A: ; +B: ; +]]) +AT_DATA([[sr.y]], +[[%glr-parser +%% +start: 'a' | A 'a' ; +A: ; +]]) +AT_DATA([[rr.y]], +[[%glr-parser +%% +start: A | B ; +A: ; +B: ; +]]) + +AT_BISON_CHECK([[sr-rr.y]], [[0]], [[]], +[[sr-rr.y: conflicts: 1 shift/reduce, 1 reduce/reduce +]]) +AT_BISON_CHECK([[-Wno-conflicts-sr sr-rr.y]], [[0]], [[]], +[[sr-rr.y: conflicts: 1 reduce/reduce +]]) +AT_BISON_CHECK([[-Wno-conflicts-rr sr-rr.y]], [[0]], [[]], +[[sr-rr.y: conflicts: 1 shift/reduce +]]) + +[for gram in sr-rr sr rr; do + for sr_exp_i in '' 0 1 2; do + for rr_exp_i in '' 0 1 2; do + test -z "$sr_exp_i" && test -z "$rr_exp_i" && continue + + # Build grammar file. + sr_exp=0 + rr_exp=0 + file=$gram + directives= + if test -n "$sr_exp_i"; then + sr_exp=$sr_exp_i + file=$file-expect-$sr_exp + directives="%expect $sr_exp" + fi + if test -n "$rr_exp_i"; then + rr_exp=$rr_exp_i + file=$file-expect-rr-$rr_exp + directives="$directives %expect-rr $rr_exp" + fi + file=$file.y + echo "$directives" > $file + cat $gram.y >> $file + + # Count actual conflicts. + conflicts= + sr_count=0 + rr_count=0 + if test $gram = sr || test $gram = sr-rr; then + conflicts="1 shift/reduce" + sr_count=1 + fi + if test $gram = rr || test $gram = sr-rr; then + if test -n "$conflicts"; then + conflicts="$conflicts, " + fi + conflicts="${conflicts}1 reduce/reduce" + rr_count=1 + fi + + # Run tests. + if test $sr_count -eq $sr_exp && test $rr_count -eq $rr_exp; then + ]AT_BISON_CHECK([[-Wnone $file]])[ + ]AT_BISON_CHECK([[-Werror $file]])[ + else + echo "$file: conflicts: $conflicts" > experr + if test $sr_count -ne $sr_exp; then + if test $sr_exp -ne 1; then s=s; else s= ; fi + echo "$file: expected $sr_exp shift/reduce conflict$s" >> experr + fi + if test $rr_count -ne $rr_exp; then + if test $rr_exp -ne 1; then s=s; else s= ; fi + echo "$file: expected $rr_exp reduce/reduce conflict$s" >> experr + fi + ]AT_BISON_CHECK([[-Wnone $file]], [[1]], [[]], [[experr]])[ + ]AT_BISON_CHECK([[-Werror $file]], [[1]], [[]], [[experr]])[ + fi + done + done +done] + +AT_CLEANUP