parse.lac: implement exploratory stack reallocations.

* data/yacc.c: Rename %define variable parse.lac.es-capacity to
parse.lac.es-capacity-initial.  Accept parse.lac.memory-trace
with values of "failures" (default) or "full".
(b4_declare_parser_state_variables): Add yyesa, yyes, and
yyes_capacity variables.
(YYSTACK_USE_ALLOCA): Ignore it if LAC requested.
(YYSTACK_ALLOC, YYSTACK_FREE, YYSTACK_ALLOC_MAXIMUM): Define if
LAC requested.
(YYCOPY_NEEDED): New cpp macro.
(YYCOPY): Define if LAC requested.
(yy_lac_stack_realloc): New function implementing stack
reallocations.  Use YYMAXDEPTH for maximum stack size given that
the stack should never need to grow larger than the main state
stack needs to grow without LAC.
(YY_LAC_ESTABLISH): Update yy_lac invocation.
(yy_lac): Add arguments for exploratory stack memory data
recorded in the main parser.  Invoke yy_lac_stack_realloc when
reallocation is necessary.
(yysyntax_error): Add the same new arguments and pass them to
yy_lac.
(yypstate_delete): Free yyes if necessary.
(yyesa, yyes, yyes_capacity): #define these to yypstate members
in the case of push parsing.
(yyparse, yypush_parse): Initialize yyes and yyes_capacity.
Update yysyntax_error invocations.  At yyreturn, free yyes if
necessary.
* src/parse-gram.y: %define parse.lac full.
* tests/input.at (LAC: errors for %define): Extend for
parse.lac-memory-trace.
* tests/regression.at (LAC: Exploratory stack): Extend to check
that stack reallocs happen when expected.
(LAC: Memory exhaustion): Update to use YYMAXDEPTH and
parse.lac.es-capacity-initial.

tests/input.at

@@ -1306,5 +1306,9 @@ AT_BISON_CHECK([[-Dparse.lac.es-capacity-initial=1 input.y]],
                [[1]], [],
 [[<command line>:2: %define variable `parse.lac.es-capacity-initial' is not used
 ]])
+AT_BISON_CHECK([[-Dparse.lac.memory-trace=full input.y]],
+               [[1]], [],
+[[<command line>:2: %define variable `parse.lac.memory-trace' is not used
+]])
 
 AT_CLEANUP

tests/regression.at

@@ -1498,6 +1498,8 @@ AT_DATA_GRAMMAR([input.y],
 // default reductions in inconsistent states
 // v   v v   v v v v   v v v v v v v
 S: A B A A B A A A A B A A A A A A A B C C A A A A A A A A A A A A B ;
+//       ^                     ^                               ^
+// LAC reallocs
 
 A: 'a' | /*empty*/ { printf ("inconsistent default reduction\n"); } ;
 B: 'b' ;
@@ -1527,9 +1529,8 @@ main (void)
 }
 ]])
 
-# Give exactly the right amount of memory to be sure there's no
-# off-by-one error, for example.
-AT_BISON_CHECK([[-Dparse.lac=full -Dparse.lac.es-capacity=12 \
+AT_BISON_CHECK([[-Dparse.lac=full -Dparse.lac.es-capacity-initial=1 \
+                 -Dparse.lac.memory-trace=full \
                  -t -o input.c input.y]], [[0]], [],
 [[input.y: conflicts: 21 shift/reduce
 ]])
@@ -1552,6 +1553,11 @@ AT_CHECK([[perl -0777 -ne 'print s/inconsistent default reduction//g;' \
 AT_CHECK([[perl -0777 -ne 'print s/\bconsistent default reduction//g;' \
            < stdout.txt || exit 77]], [[0]], [[2]])
 
+# Check number of reallocs to be sure reallocated memory isn't somehow
+# lost between LAC invocations.
+AT_CHECK([[perl -0777 -ne 'print s/\(realloc//g;' < stderr.txt \
+           || exit 77]], [[0]], [[3]])
+
 AT_BISON_OPTION_POPDEFS
 ])
 
@@ -1579,6 +1585,7 @@ AT_DATA_GRAMMAR([input.y],
   #include <stdio.h>
   void yyerror (char const *);
   int yylex (void);
+  #define YYMAXDEPTH 8
 }
 
 %error-verbose
@@ -1611,7 +1618,7 @@ main (void)
 }
 ]])
 
-AT_BISON_CHECK([[-Dparse.lac=full -Dparse.lac.es-capacity=8 \
+AT_BISON_CHECK([[-Dparse.lac=full -Dparse.lac.es-capacity-initial=1 \
                  -t -o input.c input.y]], [[0]], [],
 [[input.y: conflicts: 8 shift/reduce
 ]])
@@ -1626,7 +1633,7 @@ AT_PARSER_CHECK([[./input]], [[2]], [[]],
 Entering state 0
 Reading a token: Now at end of input.
 LAC: initial context established for $end
-LAC: checking lookahead $end: R2 G3 R2 G5 R2 G6 R2 G7 R2 G8 R2 G9 R2 G10 R2 G11 R2 (max stack size exceeded)
+LAC: checking lookahead $end: R2 G3 R2 G5 R2 G6 R2 G7 R2 G8 R2 G9 R2 G10 R2 G11 R2 (max size exceeded)
 memory exhausted
 Cleanup: discarding lookahead token $end ()
 Stack now 0
@@ -1642,7 +1649,7 @@ Reading a token: Next token is token $undefined ()
 LAC: initial context established for $undefined
 LAC: checking lookahead $undefined: Always Err
 Constructing syntax error message
-LAC: checking lookahead $end: R2 G3 R2 G5 R2 G6 R2 G7 R2 G8 R2 G9 R2 G10 R2 G11 R2 (max stack size exceeded)
+LAC: checking lookahead $end: R2 G3 R2 G5 R2 G6 R2 G7 R2 G8 R2 G9 R2 G10 R2 G11 R2 (max size exceeded)
 syntax error
 memory exhausted
 Cleanup: discarding lookahead token $undefined ()