Future/bison
1
0
Fork 0
mirror of https://git.savannah.gnu.org/git/bison.git synced 2026-03-21 10:13:03 +00:00
Code Issues Packages Projects Releases Wiki Activity

* data/glr.c (yyresolveLocations): Remove bogus YYASSERT that the

Browse Source 
state before an empty RHS is always resolved here.  Only the location
of that state is guaranteed to be resolved, and that's enough.  This
fixes the remaining bug reported by Derek M. Jones in
<http://lists.gnu.org/archive/html/bug-bison/2006-05/msg00027.html>.
* tests/glr-regression.at (Uninitialized location when reporting
ambiguity): Test the above case.
Also, the embedded comments in this test case claim it checks the case
of an empty RHS that has inherited the initial location.  However, the
corresponding LHS was already resolved, so yyresolveLocations didn't
actually have reason to modify it.  Fix this by forcing
nondeterministic operation at the beginning of the parse.
This commit is contained in:
Joel E. Denny
2006-05-21 06:22:36 +00:00
parent 50cce58e9a
commit 5ad0a449d6
3 changed files with 35 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
ChangeLog
View File

@@ -1,3 +1,18 @@
2006-05-21 Joel E. Denny <jdenny@ces.clemson.edu>
* data/glr.c (yyresolveLocations): Remove bogus YYASSERT that the
state before an empty RHS is always resolved here. Only the location
of that state is guaranteed to be resolved, and that's enough. This
fixes the remaining bug reported by Derek M. Jones in
<http://lists.gnu.org/archive/html/bug-bison/2006-05/msg00027.html>.
* tests/glr-regression.at (Uninitialized location when reporting
ambiguity): Test the above case.
Also, the embedded comments in this test case claim it checks the case
of an empty RHS that has inherited the initial location. However, the
corresponding LHS was already resolved, so yyresolveLocations didn't
actually have reason to modify it. Fix this by forcing
nondeterministic operation at the beginning of the parse.
2006-05-20 Paul Eggert <eggert@cs.ucla.edu> 2006-05-20 Paul Eggert <eggert@cs.ucla.edu>
* data/c.m4 (b4_yy_symbol_print_generate): * data/c.m4 (b4_yy_symbol_print_generate):

10
data/glr.c
View File

@@ -201,7 +201,7 @@ typedef struct YYLTYPE
]]) ]])
b4_defines_if([#include @output_header_name@], b4_defines_if([#include @output_header_name@],
[b4_shared_declarations])[ [b4_shared_declarations])[
/* Enabling traces. */ /* Enabling traces. */
#ifndef YYDEBUG #ifndef YYDEBUG
@@ -1836,8 +1836,14 @@ yyresolveLocations (yyGLRState* yys1, int yyn1,
} }
else else
{ {
/* Both yyresolveAction and yyresolveLocations traverse the GSS
in reverse rightmost order. It is only necessary to invoke
yyresolveLocations on a subforest for which yyresolveAction
would have been invoked next had an ambiguity not been
detected. Thus the location of the previous state (but not
necessarily the previous state itself) is guaranteed to be
resolved already. */
yyGLRState *yyprevious = yyoption->yystate; yyGLRState *yyprevious = yyoption->yystate;
YYASSERT (yyprevious->yyresolved);
yyrhsloc[0].yystate.yyloc = yyprevious->yyloc; yyrhsloc[0].yystate.yyloc = yyprevious->yyloc;
} }
yychar_current = yychar; yychar_current = yychar;

19
tests/glr-regression.at
View File

@@ -1606,17 +1606,22 @@ AT_DATA_GRAMMAR([glr-regr17.y],
%% %%
/* Tests the case of an empty RHS that has inherited the location of the
previous nonterminal, which is unresolved. That location is reported as the
last position of the ambiguity. */
start: ambig1 empty1 | ambig2 empty2 ;
/* Tests multiple levels of yyresolveLocations recursion. */ /* Tests multiple levels of yyresolveLocations recursion. */
start: ambig1 | ambig2 ;
ambig1: sub_ambig1 | sub_ambig2 ; ambig1: sub_ambig1 | sub_ambig2 ;
ambig2: sub_ambig1 | sub_ambig2 ; ambig2: sub_ambig1 | sub_ambig2 ;
/* Tests non-empty RHS as well as empty RHS with either initial location or /* Tests the case of a non-empty RHS as well as the case of an empty RHS that
location of previous token. Both empty RHS locations are printed in the has inherited the initial location. The empty RHS's location is reported as
error message. */ the first position in the ambiguity. */
sub_ambig1: empty 'a' 'b' empty ; sub_ambig1: empty1 'a' 'b' ;
sub_ambig2: empty 'a' 'b' empty ; sub_ambig2: empty2 'a' 'b' ;
empty: ; empty1: ;
empty2: ;
%% %%