[C++ PATCH] get_fns cleanups

[C++ PATCH] get_fns cleanups

[Nathan Sidwell]

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Some random cleanups with get_fns & get_first_fn from the modules 
branch.  I started cleaning up these and is_overloaded_fn & friends, but 
that turned into a bit of a rat hole.  There's certainly more mileage to 
be gotten though.

These cleanups are generally callers unnecessarily stripping bits off 
the get_fns deals with itself.  Or in the omp error case, unnecessarily 
peeking behind the curtain of OVERLOAD abstraction.

Applied to trunk.

nathan
-- 
Nathan Sidwell

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2017-05-16  Nathan Sidwell  <nathan@acm.org>

	* pt.c (tsubst_copy_and_build): Remove unnecessary COMPONENT_REF
	peeking.
	* semantics.c (finish_id_expression): Directly init local var.
	(finish_omp_reduction_clause): Use really_overloaded_fn.
	* tree.c (get_fns): Document.  Assert we got an overload.
	(get_first_fn) Document.
	* typeck.c (cp_build_addr_expr_1): Pass arg directly to
	really_overloaded_fn.
	* typeck2.c (cxx_inomplete_type_diagnostic): Use get_first_fn directly.

Index: pt.c
===================================================================
--- pt.c	(revision 248095)
+++ pt.c	(working copy)
@@ -17187,10 +17187,9 @@ tsubst_copy_and_build (tree t,
 		    if (diag)
 		      {
 			tree fn = unq;
+
 			if (INDIRECT_REF_P (fn))
 			  fn = TREE_OPERAND (fn, 0);
-			if (TREE_CODE (fn) == COMPONENT_REF)
-			  fn = TREE_OPERAND (fn, 1);
 			if (is_overloaded_fn (fn))
 			  fn = get_first_fn (fn);
 
Index: semantics.c
===================================================================
--- semantics.c	(revision 248095)
+++ semantics.c	(working copy)
@@ -3749,9 +3749,8 @@ finish_id_expression (tree id_expression
 	}
       else if (is_overloaded_fn (decl))
 	{
-	  tree first_fn;
+	  tree first_fn = get_first_fn (decl);
 
-	  first_fn = get_first_fn (decl);
 	  if (TREE_CODE (first_fn) == TEMPLATE_DECL)
 	    first_fn = DECL_TEMPLATE_RESULT (first_fn);
 
@@ -5615,7 +5614,6 @@ finish_omp_reduction_clause (tree c, boo
     {
       if (id == error_mark_node)
 	return true;
-      id = OVL_CURRENT (id);
       mark_used (id);
       tree body = DECL_SAVED_TREE (id);
       if (!body)
@@ -6924,13 +6922,13 @@ finish_omp_clauses (tree clauses, enum c
 	    {
 	      if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_TO_DECLARE)
 		{
-		  if (TREE_CODE (t) == OVERLOAD && OVL_CHAIN (t))
+		  if (TREE_CODE (t) == TEMPLATE_ID_EXPR)
 		    error_at (OMP_CLAUSE_LOCATION (c),
-			      "overloaded function name %qE in clause %qs", t,
+			      "template %qE in clause %qs", t,
 			      omp_clause_code_name[OMP_CLAUSE_CODE (c)]);
-		  else if (TREE_CODE (t) == TEMPLATE_ID_EXPR)
+		  else if (really_overloaded_fn (t))
 		    error_at (OMP_CLAUSE_LOCATION (c),
-			      "template %qE in clause %qs", t,
+			      "overloaded function name %qE in clause %qs", t,
 			      omp_clause_code_name[OMP_CLAUSE_CODE (c)]);
 		  else
 		    error_at (OMP_CLAUSE_LOCATION (c),
Index: tree.c
===================================================================
--- tree.c	(revision 248095)
+++ tree.c	(working copy)
@@ -2146,10 +2146,11 @@ really_overloaded_fn (tree x)
   return is_overloaded_fn (x) == 2;
 }
 
+/* Get the overload set FROM refers to.  */
+
 tree
 get_fns (tree from)
 {
-  gcc_assert (is_overloaded_fn (from));
   /* A baselink is also considered an overloaded function.  */
   if (TREE_CODE (from) == OFFSET_REF
       || TREE_CODE (from) == COMPONENT_REF)
@@ -2158,9 +2159,13 @@ get_fns (tree from)
     from = BASELINK_FUNCTIONS (from);
   if (TREE_CODE (from) == TEMPLATE_ID_EXPR)
     from = TREE_OPERAND (from, 0);
+  gcc_assert (TREE_CODE (from) == OVERLOAD
+	      || TREE_CODE (from) == FUNCTION_DECL);
   return from;
 }
 
+/* Return the first function of the overload set FROM refers to.  */
+
 tree
 get_first_fn (tree from)
 {
Index: typeck.c
===================================================================
--- typeck.c	(revision 248095)
+++ typeck.c	(working copy)
@@ -5603,7 +5603,7 @@ cp_build_addr_expr_1 (tree arg, bool str
   gcc_assert (!identifier_p (arg) || !IDENTIFIER_OPNAME_P (arg));
 
   if (TREE_CODE (arg) == COMPONENT_REF && type_unknown_p (arg)
-      && !really_overloaded_fn (TREE_OPERAND (arg, 1)))
+      && !really_overloaded_fn (arg))
     {
       /* They're trying to take the address of a unique non-static
 	 member function.  This is ill-formed (except in MS-land),
Index: typeck2.c
===================================================================
--- typeck2.c	(revision 248095)
+++ typeck2.c	(working copy)
@@ -506,9 +506,8 @@ cxx_incomplete_type_diagnostic (location
     case OFFSET_TYPE:
     bad_member:
       {
-	tree member = TREE_OPERAND (value, 1);
-	if (is_overloaded_fn (member))
-	  member = get_first_fn (member);
+	tree member = get_first_fn (TREE_OPERAND (value, 1));
+
 	if (DECL_FUNCTION_MEMBER_P (member)
 	    && ! flag_ms_extensions)
 	  emit_diagnostic (diag_kind, loc, 0,

Re: [C++ PATCH] get_fns cleanups

[Jason Merrill]

The change to cxx_incomplete_type_diagnostic seems wrong; the member
might be a data member.

Jason

Re: [C++ PATCH] get_fns cleanups

[Nathan Sidwell]

On 05/16/2017 10:50 AM, Jason Merrill wrote:
> The change to cxx_incomplete_type_diagnostic seems wrong; the member
> might be a data member.

I had convinced myself that at that point it couldn't be.  Will take 
another look though.

Anyway, thanks for the review!

nathan


-- 
Nathan Sidwell

Re: [C++ PATCH] get_fns cleanups

[Nathan Sidwell]

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On 05/16/2017 10:50 AM, Jason Merrill wrote:
> The change to cxx_incomplete_type_diagnostic seems wrong; the member
> might be a data member.

I couldn't get there with a non-overload, but then I couldn't convince 
myself there was no other path.  It's hardly a critical path, so reverted.

-- 
Nathan Sidwell

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2017-05-16  Nathan Sidwell  <nathan@acm.org>

	* typeck2.c (cxx_incomplete_type_diagnostic): Revert change and
	check is_overloaded_fn.

Index: typeck2.c
===================================================================
--- typeck2.c	(revision 248109)
+++ typeck2.c	(working copy)
@@ -506,7 +506,9 @@ cxx_incomplete_type_diagnostic (location
     case OFFSET_TYPE:
     bad_member:
       {
-	tree member = get_first_fn (TREE_OPERAND (value, 1));
+	tree member = TREE_OPERAND (value, 1);
+	if (is_overloaded_fn (member))
+	  member = get_first_fn (member);
 
 	if (DECL_FUNCTION_MEMBER_P (member)
 	    && ! flag_ms_extensions)