Re: [PATCH] c-family: copy attribute diagnostic fixes [PR113262]

[Jason Merrill]

On 1/9/24 03:52, Jakub Jelinek wrote:
Hi!
The copy attributes is allowed on decls as well as types and even has
checks whether decl (set to *node) is DECL_P or TYPE_P, but for diagnostics
unconditionally uses DECL_SOURCE_LOCATION (decl), which obviously only works
if it applies to a decl.

In the C++ front-end location_of checks to see if the type has a 
TYPE_MAIN_DECL to get a location from, you might do that if !DECL_P?  OK 
either way.

The following patch fixes that, bootstrapped/regtested on x86_64-linux and
i686-linux, ok for trunk?

2024-01-09  Jakub Jelinek  <ja...@redhat.com>

        PR c/113262
        * c-attribs.cc (handle_copy_attribute): Don't use
        DECL_SOURCE_LOCATION (decl) if decl is not DECL_P, use input_location
        instead.  Formatting fixes.

        * gcc.dg/pr113262.c: New test.

--- gcc/c-family/c-attribs.cc.jj        2024-01-03 12:07:02.020736256 +0100
+++ gcc/c-family/c-attribs.cc   2024-01-08 22:10:04.789616664 +0100
@@ -3143,13 +3143,14 @@ handle_copy_attribute (tree *node, tree
    if (ref == error_mark_node)
      return NULL_TREE;
  
+  location_t loc = input_location;
+  if (DECL_P (decl))
+    loc = DECL_SOURCE_LOCATION (decl);
    if (TREE_CODE (ref) == STRING_CST)
      {
        /* Explicitly handle this case since using a string literal
         as an argument is a likely mistake.  */
-      error_at (DECL_SOURCE_LOCATION (decl),
-               "%qE attribute argument cannot be a string",
-               name);
+      error_at (loc, "%qE attribute argument cannot be a string", name);
        return NULL_TREE;
      }
  
@@ -3160,10 +3161,8 @@ handle_copy_attribute (tree *node, tree
        /* Similar to the string case, since some function attributes
         accept literal numbers as arguments (e.g., alloc_size or
         nonnull) using one here is a likely mistake.  */
-      error_at (DECL_SOURCE_LOCATION (decl),
-               "%qE attribute argument cannot be a constant arithmetic "
-               "expression",
-               name);
+      error_at (loc, "%qE attribute argument cannot be a constant arithmetic "
+               "expression", name);
        return NULL_TREE;
      }
  
@@ -3171,12 +3170,11 @@ handle_copy_attribute (tree *node, tree
      {
        /* Another possible mistake (but indirect self-references aren't
         and diagnosed and shouldn't be).  */
-      if (warning_at (DECL_SOURCE_LOCATION (decl), OPT_Wattributes,
+      if (warning_at (loc, OPT_Wattributes,
                      "%qE attribute ignored on a redeclaration "
-                     "of the referenced symbol",
-                     name))
-       inform (DECL_SOURCE_LOCATION (node[1]),
-               "previous declaration here");
+                     "of the referenced symbol", name)
+         && DECL_P (node[1]))
+       inform (DECL_SOURCE_LOCATION (node[1]), "previous declaration here");
        return NULL_TREE;
      }
  
@@ -3196,7 +3194,8 @@ handle_copy_attribute (tree *node, tree
        ref = TREE_OPERAND (ref, 1);
        else
        break;
-    } while (!DECL_P (ref));
+    }
+  while (!DECL_P (ref));
  
    /* For object pointer expressions, consider those to be requests
       to copy from their type, such as in:
@@ -3228,8 +3227,7 @@ handle_copy_attribute (tree *node, tree
             to a variable, or variable attributes to a function.  */
          if (warning (OPT_Wattributes,
                       "%qE attribute ignored on a declaration of "
-                      "a different kind than referenced symbol",
-                      name)
+                      "a different kind than referenced symbol", name)
              && DECL_P (ref))
            inform (DECL_SOURCE_LOCATION (ref),
                    "symbol %qD referenced by %qD declared here", ref, decl);
@@ -3279,9 +3277,7 @@ handle_copy_attribute (tree *node, tree
      }
    else if (!TYPE_P (decl))
      {
-      error_at (DECL_SOURCE_LOCATION (decl),
-               "%qE attribute must apply to a declaration",
-               name);
+      error_at (loc, "%qE attribute must apply to a declaration", name);
        return NULL_TREE;
      }
  
--- gcc/testsuite/gcc.dg/pr113262.c.jj	2024-01-08 22:19:07.414588762 +0100
+++ gcc/testsuite/gcc.dg/pr113262.c     2024-01-08 22:18:51.327815573 +0100
@@ -0,0 +1,6 @@
+/* PR c/113262 */
+/* { dg-do compile } */
+/* { dg-options "" } */
+
+int [[gnu::copy ("")]] a;    /* { dg-error "'copy' attribute argument cannot be a 
string" } */
+

        Jakub