Sync libiberty with upstream GCC.

libiberty/ChangeLog:

	PR demangler/80513
	* cp-demangle.c (d_number): Check for overflow.
	* cplus-dem.c (consume_count): Fix overflow check.
	(gnu_special): Check for underscore after thunk delta.
	* testsuite/demangle-expected: Add tests for overflows and invalid
	characters in thunks.

	* cp-demangle.c (MAX_RECURSION_COUNT): New constant.
	(struct d_print_info): Add recursion field.
	(d_print_init): Initialize recursion.
	(d_print_comp): Check and update d_print_info recursion depth.

	* cp-demangle.c (d_substitution): Return NULL if d_add_substitution
	fails.

	* cp-demangle.h (struct d_info): Remove did_subs field.
	* cp-demangle.c (struct d_info_checkpoint): Likewise.
	(d_template_param): Don't update did_subs.
	(d_substitution): Likewise.
	(d_checkpoint): Don't assign did_subs.
	(d_backtrack): Likewise.
	(cplus_demangle_init_info): Don't initialize did_subs.

libiberty/cp-demangle.c

@@ -316,10 +316,12 @@ struct d_info_checkpoint
   const char *n;
   int next_comp;
   int next_sub;
-  int did_subs;
   int expansion;
 };
 
+/* Maximum number of times d_print_comp may be called recursively.  */
+#define MAX_RECURSION_COUNT 1024
+
 enum { D_PRINT_BUFFER_LENGTH = 256 };
 struct d_print_info
 {
@@ -342,6 +344,9 @@ struct d_print_info
   struct d_print_mod *modifiers;
   /* Set to 1 if we saw a demangling error.  */
   int demangle_failure;
+  /* Number of times d_print_comp was recursively called.  Should not
+     be bigger than MAX_RECURSION_COUNT.  */
+  int recursion;
   /* Non-zero if we're printing a lambda argument.  A template
      parameter reference actually means 'auto'.  */
   int is_lambda_arg;
@@ -1687,6 +1692,8 @@ d_number (struct d_info *di)
 	    ret = - ret;
 	  return ret;
 	}
+      if (ret > ((INT_MAX - (peek - '0')) / 10))
+        return -1;
       ret = ret * 10 + peek - '0';
       d_advance (di, 1);
       peek = d_peek_char (di);
@@ -3075,8 +3082,6 @@ d_template_param (struct d_info *di)
   if (param < 0)
     return NULL;
 
-  ++di->did_subs;
-
   return d_make_template_param (di, param);
 }
 
@@ -3846,8 +3851,6 @@ d_substitution (struct d_info *di, int prefix)
       if (id >= (unsigned int) di->next_sub)
 	return NULL;
 
-      ++di->did_subs;
-
       return di->subs[id];
     }
   else
@@ -3896,7 +3899,8 @@ d_substitution (struct d_info *di, int prefix)
 		  /* If there are ABI tags on the abbreviation, it becomes
 		     a substitution candidate.  */
 		  dc = d_abi_tags (di, dc);
-		  d_add_substitution (di, dc);
+		  if (! d_add_substitution (di, dc))
+		    return NULL;
 		}
 	      return dc;
 	    }
@@ -3912,7 +3916,6 @@ d_checkpoint (struct d_info *di, struct d_info_checkpoint *checkpoint)
   checkpoint->n = di->n;
   checkpoint->next_comp = di->next_comp;
   checkpoint->next_sub = di->next_sub;
-  checkpoint->did_subs = di->did_subs;
   checkpoint->expansion = di->expansion;
 }
 
@@ -3922,7 +3925,6 @@ d_backtrack (struct d_info *di, struct d_info_checkpoint *checkpoint)
   di->n = checkpoint->n;
   di->next_comp = checkpoint->next_comp;
   di->next_sub = checkpoint->next_sub;
-  di->did_subs = checkpoint->did_subs;
   di->expansion = checkpoint->expansion;
 }
 
@@ -4157,6 +4159,7 @@ d_print_init (struct d_print_info *dpi, demangle_callbackref callback,
   dpi->opaque = opaque;
 
   dpi->demangle_failure = 0;
+  dpi->recursion = 0;
   dpi->is_lambda_arg = 0;
 
   dpi->component_stack = NULL;
@@ -5691,13 +5694,14 @@ d_print_comp (struct d_print_info *dpi, int options,
 	      struct demangle_component *dc)
 {
   struct d_component_stack self;
-  if (dc == NULL || dc->d_printing > 1)
+  if (dc == NULL || dc->d_printing > 1 || dpi->recursion > MAX_RECURSION_COUNT)
     {
       d_print_error (dpi);
       return;
     }
-  else
-    dc->d_printing++;
+
+  dc->d_printing++;
+  dpi->recursion++;
 
   self.dc = dc;
   self.parent = dpi->component_stack;
@@ -5707,6 +5711,7 @@ d_print_comp (struct d_print_info *dpi, int options,
 
   dpi->component_stack = self.parent;
   dc->d_printing--;
+  dpi->recursion--;
 }
 
 /* Print a Java dentifier.  For Java we try to handle encoded extended
@@ -6159,7 +6164,6 @@ cplus_demangle_init_info (const char *mangled, int options, size_t len,
      chars in the mangled string.  */
   di->num_subs = len;
   di->next_sub = 0;
-  di->did_subs = 0;
 
   di->last_name = NULL;