[C++ PATCH] * cp-tree.h (class iloc_sentinel): New.

[Jason Merrill <jason at redhat dot com>]

We didn't already have an RAII sentinel for input_location, and while
temp_override would work, it would also happily set input_location to 0,
which breaks things that try to look up the associated filename.

Tested x86_64-pc-linux-gnu, applying to trunk.

	* decl.c (grokdeclarator, finish_enum_value_list): Use it.
	* mangle.c (mangle_decl_string): Use it.
	* pt.c (perform_typedefs_access_check): Use it.
---
 gcc/cp/cp-tree.h | 18 ++++++++++++++++++
 gcc/cp/decl.c    | 15 +++++----------
 gcc/cp/mangle.c  |  4 +---
 gcc/cp/pt.c      |  5 +----
 gcc/cp/ChangeLog |  7 +++++++
 5 files changed, 32 insertions(+), 17 deletions(-)

diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 8fc3fc1f78b..be1a44e4373 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -1762,6 +1762,24 @@ public:
   ~warning_sentinel() { flag = val; }
 };
 
+/* RAII sentinel to temporarily override input_location.  This will not set
+   input_location to UNKNOWN_LOCATION or BUILTINS_LOCATION.  */
+
+class iloc_sentinel
+{
+  location_t saved_loc;
+public:
+  iloc_sentinel (location_t loc): saved_loc (input_location)
+  {
+    if (loc >= RESERVED_LOCATION_COUNT)
+      input_location = loc;
+  }
+  ~iloc_sentinel ()
+  {
+    input_location = saved_loc;
+  }
+};
+
 /* RAII sentinel that saves the value of a variable, optionally
    overrides it right away, and restores its value when the sentinel
    id destructed.  */
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index b753796609a..67c4521e98c 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -10523,7 +10523,6 @@ grokdeclarator (const cp_declarator *declarator,
   bool constinit_p = decl_spec_seq_has_spec_p (declspecs, ds_constinit);
   bool late_return_type_p = false;
   bool array_parameter_p = false;
-  location_t saved_loc = input_location;
   tree reqs = NULL_TREE;
 
   signed_p = decl_spec_seq_has_spec_p (declspecs, ds_signed);
@@ -11514,9 +11513,10 @@ grokdeclarator (const cp_declarator *declarator,
 
 	    /* Declaring a function type.  */
 
-	    input_location = declspecs->locations[ds_type_spec];
-	    abstract_virtuals_error (ACU_RETURN, type);
-	    input_location = saved_loc;
+	    {
+	      iloc_sentinel ils (declspecs->locations[ds_type_spec]);
+	      abstract_virtuals_error (ACU_RETURN, type);
+	    }
 
 	    /* Pick up type qualifiers which should be applied to `this'.  */
 	    memfn_quals = declarator->u.function.qualifiers;
@@ -15061,11 +15061,8 @@ finish_enum_value_list (tree enumtype)
      type of the enumeration.  */
   for (values = TYPE_VALUES (enumtype); values; values = TREE_CHAIN (values))
     {
-      location_t saved_location;
-
       decl = TREE_VALUE (values);
-      saved_location = input_location;
-      input_location = DECL_SOURCE_LOCATION (decl);
+      iloc_sentinel ils (DECL_SOURCE_LOCATION (decl));
       if (fixed_underlying_type_p)
         /* If the enumeration type has a fixed underlying type, we
            already checked all of the enumerator values.  */
@@ -15074,8 +15071,6 @@ finish_enum_value_list (tree enumtype)
         value = perform_implicit_conversion (underlying_type,
                                              DECL_INITIAL (decl),
                                              tf_warning_or_error);
-      input_location = saved_location;
-
       /* Do not clobber shared ints.  */
       if (value != error_mark_node)
 	{
diff --git a/gcc/cp/mangle.c b/gcc/cp/mangle.c
index 4d6f58093c1..a9333b84349 100644
--- a/gcc/cp/mangle.c
+++ b/gcc/cp/mangle.c
@@ -3791,7 +3791,6 @@ static tree
 mangle_decl_string (const tree decl)
 {
   tree result;
-  location_t saved_loc = input_location;
   tree saved_fn = NULL_TREE;
   bool template_p = false;
 
@@ -3809,7 +3808,7 @@ mangle_decl_string (const tree decl)
 	  current_function_decl = NULL_TREE;
 	}
     }
-  input_location = DECL_SOURCE_LOCATION (decl);
+  iloc_sentinel ils (DECL_SOURCE_LOCATION (decl));
 
   start_mangling (decl);
 
@@ -3828,7 +3827,6 @@ mangle_decl_string (const tree decl)
       pop_tinst_level ();
       current_function_decl = saved_fn;
     }
-  input_location = saved_loc;
 
   return result;
 }
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index e5d64989b32..5a2dfbbd994 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -10941,7 +10941,6 @@ apply_late_template_attributes (tree *decl_p, tree attributes, int attr_flags,
 static void
 perform_typedefs_access_check (tree tmpl, tree targs)
 {
-  location_t saved_location;
   unsigned i;
   qualified_typedef_usage_t *iter;
 
@@ -10950,7 +10949,6 @@ perform_typedefs_access_check (tree tmpl, tree targs)
 	  && TREE_CODE (tmpl) != FUNCTION_DECL))
     return;
 
-  saved_location = input_location;
   FOR_EACH_VEC_SAFE_ELT (get_types_needing_access_check (tmpl), i, iter)
     {
       tree type_decl = iter->typedef_decl;
@@ -10966,12 +10964,11 @@ perform_typedefs_access_check (tree tmpl, tree targs)
 
       /* Make access check error messages point to the location
          of the use of the typedef.  */
-      input_location = iter->locus;
+      iloc_sentinel ils (iter->locus);
       perform_or_defer_access_check (TYPE_BINFO (type_scope),
 				     type_decl, type_decl,
 				     tf_warning_or_error);
     }
-    input_location = saved_location;
 }
 
 static tree
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 3a3ef9ed250..8e92d91ef8e 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,10 @@
+2019-09-27  Jason Merrill  <jason@redhat.com>
+
+	* cp-tree.h (class iloc_sentinel): New.
+	* decl.c (grokdeclarator, finish_enum_value_list): Use it.
+	* mangle.c (mangle_decl_string): Use it.
+	* pt.c (perform_typedefs_access_check): Use it.
+
 2019-09-27  Richard Sandiford  <richard.sandiford@arm.com>
 
 	* cp-tree.h (build_cxx_call): Take the original function decl

base-commit: 332b7382841f3d564b62608457eb92ede5bd7bb5
-- 
2.21.0