* data/glr.c (yyresolveValue): When merging semantic options, if at

least one user action succeeds but a later one cuts the parse, then destroy the semantic value before returning rather than leaking it. (yyresolveStates): If a user action cuts the parse and thus yyresolveValue fails, ignore the (unset) semantic value rather than corrupting the yyGLRState, and empty the semantic options list since the user actions should have called all necessary destructors. Simplify code with YYCHK. * tests/glr-regression.at (Corrupted semantic options if user action cuts parse): New test case. (Undesirable destructors if user action cuts parse): New test case. Before applying any of this patch, this test case never actually failed for me... but only because the corrupted semantic options usually masked this bug. (Leaked merged semantic value if user action cuts parse): New test case.
2026-03-09 12:23:04 +00:00 · 2006-01-05 21:07:54 +00:00
parent 6ec2c0f295
commit d659304d0a
3 changed files with 242 additions and 14 deletions
--- a/tests/glr-regression.at
+++ b/tests/glr-regression.at
@@ -815,3 +815,203 @@ AT_CHECK([[./glr-regr9]], 0, [],
 ])

 AT_CLEANUP
+
+
+## ------------------------------------------------------------------------- ##
+## Corrupted semantic options if user action cuts parse.	             ##
+## ------------------------------------------------------------------------- ##
+
+AT_SETUP([Corrupted semantic options if user action cuts parse.])
+
+AT_DATA_GRAMMAR([glr-regr10.y],
+[[
+%{
+# include <stdio.h>
+  static void yyerror (char const *);
+  static int yylex (void);
+  #define GARBAGE_SIZE 50
+  static char garbage[GARBAGE_SIZE];
+%}
+
+%glr-parser
+%union { char *ptr; }
+%type <ptr> start
+
+%%
+
+start:
+    %dprec 2 { $$ = garbage; YYACCEPT; }
+  | %dprec 1 { $$ = garbage; YYACCEPT; }
+  ;
+
+%%
+
+static void
+yyerror (char const *msg)
+{
+  fprintf (stderr, "%s\n", msg);
+}
+
+static int
+yylex (void)
+{
+  return 0;
+}
+
+int
+main (void)
+{
+  int index;
+  for (index = 0; index < GARBAGE_SIZE; index+=1)
+    garbage[index] = 132;
+  return yyparse ();
+}
+]])
+
+AT_CHECK([[bison -t -o glr-regr10.c glr-regr10.y]], 0, [],
+[glr-regr10.y: conflicts: 1 reduce/reduce
+])
+AT_COMPILE([glr-regr10])
+
+AT_CHECK([[./glr-regr10]], 0, [], [])
+
+AT_CLEANUP
+
+
+## ------------------------------------------------------------------------- ##
+## Undesirable destructors if user action cuts parse.			     ##
+## ------------------------------------------------------------------------- ##
+
+AT_SETUP([Undesirable destructors if user action cuts parse.])
+
+AT_DATA_GRAMMAR([glr-regr11.y],
+[[
+%{
+# include <stdlib.h>
+  static void yyerror (char const *);
+  static int yylex (void);
+  static int destructors = 0;
+# define USE(val)
+%}
+
+%glr-parser
+%union { int dummy; }
+%type <int> 'a'
+%destructor { destructors += 1; } 'a'
+
+%%
+
+start:
+    'a' %dprec 2 { USE ($1); destructors += 1; YYACCEPT; }
+  | 'a' %dprec 1 { USE ($1); destructors += 1; YYACCEPT; }
+  ;
+
+%%
+
+static void
+yyerror (char const *msg)
+{
+  fprintf (stderr, "%s\n", msg);
+}
+
+static int
+yylex (void)
+{
+  static char const *input = "a";
+  return *input++;
+}
+
+int
+main (void)
+{
+  int exit_status = yyparse ();
+  if (destructors != 1)
+    {
+      fprintf (stderr, "Destructor calls: %d\n", destructors);
+      return 1;
+    }
+  return exit_status;
+}
+]])
+
+AT_CHECK([[bison -t -o glr-regr11.c glr-regr11.y]], 0, [],
+[glr-regr11.y: conflicts: 1 reduce/reduce
+])
+AT_COMPILE([glr-regr11])
+
+AT_CHECK([[./glr-regr11]], 0, [], [])
+
+AT_CLEANUP
+
+
+## ------------------------------------------------------------------------- ##
+## Leaked merged semantic value if user action cuts parse.		     ##
+## ------------------------------------------------------------------------- ##
+
+AT_SETUP([Leaked merged semantic value if user action cuts parse.])
+
+AT_DATA_GRAMMAR([glr-regr12.y],
+[[
+%glr-parser
+%union { int dummy; }
+%type <dummy> start
+%destructor { has_value = 0; } start
+
+%{
+# include <stdlib.h>
+  static int merge (YYSTYPE, YYSTYPE);
+  static void yyerror (char const *);
+  static int yylex (void);
+  static int has_value = 0;
+# define USE(val)
+%}
+
+%%
+
+start:
+    %merge<merge> { has_value = 1; USE ($$); }
+  | %merge<merge> { USE ($$); YYACCEPT; }
+  ;
+
+%%
+
+static int
+merge (YYSTYPE s1, YYSTYPE s2)
+{
+  /* Not invoked. */
+  return 0;
+}
+
+static void
+yyerror (char const *msg)
+{
+  fprintf (stderr, "%s\n", msg);
+}
+
+static int
+yylex (void)
+{
+  return 0;
+}
+
+int
+main (void)
+{
+  int exit_status = yyparse ();
+  if (has_value)
+    {
+      fprintf (stderr, "Destructor not called.\n");
+      return 1;
+    }
+  return exit_status;
+}
+]])
+
+AT_CHECK([[bison -t -o glr-regr12.c glr-regr12.y]], 0, [],
+[glr-regr12.y: conflicts: 1 reduce/reduce
+])
+AT_COMPILE([glr-regr12])
+
+AT_CHECK([[./glr-regr12]], 0, [], [])
+
+AT_CLEANUP