re PR preprocessor/92296 (internal compiler error: Segmentation fault #pragma push_macro("__LINE__"))

	PR preprocessor/92296
	* internal.h (struct def_pragma_macro): Add is_builtin bitfield.
	(_cpp_restore_special_builtin): Declare.
	* init.c (_cpp_restore_special_builtin): New function.
	* directives.c (do_pragma_push_macro): For NT_BUILTIN_MACRO
	set is_builtin and don't try to grab definition.
	(cpp_pop_definition): Use _cpp_restore_special_builtin to restore
	builtin macros.

	* c-c++-common/cpp/pr92296-1.c: New test.
	* c-c++-common/cpp/pr92296-2.c: New test.

From-SVN: r277685

4 files changed, 41 insertions, 0 deletions

diff --git a/libcpp/ChangeLog b/libcpp/ChangeLog
index 670e97b..a13f750 100644
--- a/libcpp/ChangeLog
+++ b/libcpp/ChangeLog
@@ -1,3 +1,14 @@
+2019-10-31  Jakub Jelinek  <jakub@redhat.com>
+
+	PR preprocessor/92296
+	* internal.h (struct def_pragma_macro): Add is_builtin bitfield.
+	(_cpp_restore_special_builtin): Declare.
+	* init.c (_cpp_restore_special_builtin): New function.
+	* directives.c (do_pragma_push_macro): For NT_BUILTIN_MACRO
+	set is_builtin and don't try to grab definition.
+	(cpp_pop_definition): Use _cpp_restore_special_builtin to restore
+	builtin macros.
+
 2019-10-15  Nathan Sidwell  <nathan@acm.org>
 
 	* include/line-map.h (struct maps_info_ordinary): Make cache
diff --git a/libcpp/directives.c b/libcpp/directives.c
index 61f1fef..6e011a1 100644
--- a/libcpp/directives.c
+++ b/libcpp/directives.c
@@ -1582,6 +1582,8 @@ do_pragma_push_macro (cpp_reader *pfile)
   node = _cpp_lex_identifier (pfile, c->name);
   if (node->type == NT_VOID)
     c->is_undef = 1;
+  else if (node->type == NT_BUILTIN_MACRO)
+    c->is_builtin = 1;
   else
     {
       defn = cpp_macro_definition (pfile, node);
@@ -2470,6 +2472,11 @@ cpp_pop_definition (cpp_reader *pfile, struct def_pragma_macro *c)
 
   if (c->is_undef)
     return;
+  if (c->is_builtin)
+    {
+      _cpp_restore_special_builtin (pfile, c);
+      return;
+    }
 
   {
     size_t namelen;
diff --git a/libcpp/init.c b/libcpp/init.c
index b094317..32b0e70 100644
--- a/libcpp/init.c
+++ b/libcpp/init.c
@@ -497,6 +497,25 @@ cpp_init_special_builtins (cpp_reader *pfile)
     }
 }
 
+/* Restore macro C to builtin macro definition.  */
+
+void
+_cpp_restore_special_builtin (cpp_reader *pfile, struct def_pragma_macro *c)
+{
+  size_t len = strlen (c->name);
+
+  for (const struct builtin_macro *b = builtin_array;
+       b < builtin_array + ARRAY_SIZE (builtin_array); b++)
+    if (b->len == len && memcmp (c->name, b->name, len + 1) == 0)
+      {
+	cpp_hashnode *hp = cpp_lookup (pfile, b->name, b->len);
+	hp->type = NT_BUILTIN_MACRO;
+	if (b->always_warn_if_redefined)
+	  hp->flags |= NODE_WARN;
+	hp->value.builtin = (enum cpp_builtin_type) b->value;
+      }
+}
+
 /* Read the builtins table above and enter them, and language-specific
    macros, into the hash table.  HOSTED is true if this is a hosted
    environment.  */
diff --git a/libcpp/internal.h b/libcpp/internal.h
index cd1a523..e759bec 100644
--- a/libcpp/internal.h
+++ b/libcpp/internal.h
@@ -391,6 +391,8 @@ struct def_pragma_macro {
 
   /* Mark if we save an undefined macro.  */
   unsigned int is_undef : 1;
+  /* Nonzero if it was a builtin macro.  */
+  unsigned int is_builtin : 1;
 };
 
 /* A cpp_reader encapsulates the "state" of a pre-processor run.
@@ -722,6 +724,8 @@ extern void *_cpp_commit_buff (cpp_reader *pfile, size_t size);
 /* In init.c.  */
 extern void _cpp_maybe_push_include_file (cpp_reader *);
 extern const char *cpp_named_operator2name (enum cpp_ttype type);
+extern void _cpp_restore_special_builtin (cpp_reader *pfile,
+					  struct def_pragma_macro *);
 
 /* In directives.c */
 extern int _cpp_test_assertion (cpp_reader *, unsigned int *);