check for memory exhaustion

hash_initialize returns NULL when out of memory.  Check for it, and
die cleanly instead of crashing.

Reported by 江 祖铭 (Zu-Ming Jiang).
https://lists.gnu.org/archive/html/bug-bison/2019-08/msg00015.html

* src/muscle-tab.c, src/state.c, src/symtab.c, src/uniqstr.c:
Check the value returned by hash_initialize.

THANKS

@@ -199,6 +199,7 @@ Wwp                       subscript@free.fr
 xolodho                   xolodho@gmail.com
 Zack Weinberg             zack@codesourcery.com
 長田偉伸                   cbh34680@iret.co.jp
+江 祖铭                    jjzuming@outlook.com
 
 Many people are not named here because we lost track of them.  We
 thank them!  Please, help us keeping this list up to date.

src/muscle-tab.c

@@ -128,6 +128,8 @@ muscle_init (void)
 
   muscle_table = hash_initialize (HT_INITIAL_CAPACITY, NULL, hash_muscle,
                                   hash_compare_muscles, muscle_entry_free);
+  if (!muscle_table)
+    xalloc_die ();
 
   /* Version and input file.  */
   MUSCLE_INSERT_STRING ("version", VERSION);

src/state.c

@@ -364,6 +364,8 @@ state_hash_new (void)
                                  state_hasher,
                                  state_comparator,
                                  NULL);
+  if (!state_table)
+    xalloc_die ();
 }
 
 

src/symtab.c

@@ -778,11 +778,15 @@ symbols_new (void)
                                   hash_symbol_hasher,
                                   hash_symbol_comparator,
                                   symbol_free);
+  if (!symbol_table)
+    xalloc_die ();
   semantic_type_table = hash_initialize (HT_INITIAL_CAPACITY,
                                          NULL,
                                          hash_semantic_type_hasher,
                                          hash_semantic_type_comparator,
                                          free);
+  if (!semantic_type_table)
+    xalloc_die ();
 }
 
 

src/uniqstr.c

@@ -162,6 +162,8 @@ uniqstrs_new (void)
                                     hash_uniqstr,
                                     hash_compare_uniqstr,
                                     free);
+  if (!uniqstrs_table)
+    xalloc_die ();
 }