[C][C++] Allow targets to check calls to BUILT_IN_MD functions

For SVE, we'd like the frontends to check calls to target-specific
built-in functions in the same way that they already do for "normal"
builtins.  This patch adds a target hook for that and extends
check_builtin_function_arguments accordingly.

A slight complication is that when TARGET_RESOLVE_OVERLOADED_BUILTIN
has resolved an overload, it can use build_function_call_vec to build
the call to the underlying non-overloaded function decl.  This in
turn coerces the arguments to the function type and then calls
check_builtin_function_arguments to check the final call.  If the
target does find a problem in this final call, it can be useful
to refer to the original overloaded function decl in diagnostics,
since that's what the user wrote.

The patch therefore passes the original decl as a final optional
parameter to build_function_call_vec.

2019-09-27  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* target.def (check_builtin_call): New target hook.
	* doc/tm.texi.in (TARGET_CHECK_BUILTIN_CALL): New @hook.
	* doc/tm.texi: Regenerate.

gcc/c-family/
	* c-common.h (build_function_call_vec): Take the original
	function decl as an optional final parameter.
	(check_builtin_function_arguments): Take the original function decl.
	* c-common.c (check_builtin_function_arguments): Likewise.
	Handle all built-in functions, not just BUILT_IN_NORMAL ones.
	Use targetm.check_builtin_call to check BUILT_IN_MD functions.

gcc/c/
	* c-typeck.c (build_function_call_vec): Take the original function
	decl as an optional final parameter.  Pass all built-in calls to
	check_builtin_function_arguments.

gcc/cp/
	* cp-tree.h (build_cxx_call): Take the original function decl
	as an optional final parameter.
	(cp_build_function_call_vec): Likewise.
	* call.c (build_cxx_call): Likewise.  Pass all built-in calls to
	check_builtin_function_arguments.
	* typeck.c (build_function_call_vec): Take the original function
	decl as an optional final parameter and pass it to
	cp_build_function_call_vec.
	(cp_build_function_call_vec): Take the original function
	decl as an optional final parameter and pass it to build_cxx_call.

From-SVN: r276176

13 files changed, 116 insertions, 21 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index fe6b333be6f..b6a19c4e2f7 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,11 @@
 2019-09-27  Richard Sandiford  <richard.sandiford@arm.com>
 
+	* target.def (check_builtin_call): New target hook.
+	* doc/tm.texi.in (TARGET_CHECK_BUILTIN_CALL): New @hook.
+	* doc/tm.texi: Regenerate.
+
+2019-09-27  Richard Sandiford  <richard.sandiford@arm.com>
+
 	PR tree-optimization/91909
 	* tree-vect-loop.c (vect_create_epilog_for_reduction): Take a
 	reduc_index parameter.  When handling COND_REDUCTION, make sure
diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index 93bdf3e0798..7b10957ad02 100644
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,12 @@
+2019-09-27  Richard Sandiford  <richard.sandiford@arm.com>
+
+	* c-common.h (build_function_call_vec): Take the original
+	function decl as an optional final parameter.
+	(check_builtin_function_arguments): Take the original function decl.
+	* c-common.c (check_builtin_function_arguments): Likewise.
+	Handle all built-in functions, not just BUILT_IN_NORMAL ones.
+	Use targetm.check_builtin_call to check BUILT_IN_MD functions.
+
 2019-09-15  Jason Merrill  <jason@redhat.com>
 
 	* c-warn.c (warn_logical_operator): Strip location wrappers.  Don't
diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index 3756219e5cf..7169813d0f2 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -5856,15 +5856,27 @@ builtin_function_validate_nargs (location_t loc, tree fndecl, int nargs,
 /* Verifies the NARGS arguments ARGS to the builtin function FNDECL.
    Returns false if there was an error, otherwise true.  LOC is the
    location of the function; ARG_LOC is a vector of locations of the
-   arguments.  */
+   arguments.  If FNDECL is the result of resolving an overloaded
+   target built-in, ORIG_FNDECL is the original function decl,
+   otherwise it is null.  */
 
 bool
 check_builtin_function_arguments (location_t loc, vec<location_t> arg_loc,
-				  tree fndecl, int nargs, tree *args)
+				  tree fndecl, tree orig_fndecl,
+				  int nargs, tree *args)
 {
-  if (!fndecl_built_in_p (fndecl, BUILT_IN_NORMAL))
+  if (!fndecl_built_in_p (fndecl))
     return true;
 
+  if (DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_MD)
+    return (!targetm.check_builtin_call
+	    || targetm.check_builtin_call (loc, arg_loc, fndecl,
+					   orig_fndecl, nargs, args));
+
+  if (DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_FRONTEND)
+    return true;
+
+  gcc_assert (DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL);
   switch (DECL_FUNCTION_CODE (fndecl))
     {
     case BUILT_IN_ALLOCA_WITH_ALIGN_AND_MAX:
diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h
index a9f4d0c5c11..c1554f3c3af 100644
--- a/gcc/c-family/c-common.h
+++ b/gcc/c-family/c-common.h
@@ -818,7 +818,7 @@ extern void check_function_arguments_recurse (void (*)
 					      void *, tree,
 					      unsigned HOST_WIDE_INT);
 extern bool check_builtin_function_arguments (location_t, vec<location_t>,
-					      tree, int, tree *);
+					      tree, tree, int, tree *);
 extern void check_function_format (const_tree, tree, int, tree *,
 				   vec<location_t> *);
 extern bool attribute_fallthrough_p (tree);
@@ -995,7 +995,8 @@ extern bool c_switch_covers_all_cases_p (splay_tree, tree);
 extern tree build_function_call (location_t, tree, tree);
 
 extern tree build_function_call_vec (location_t, vec<location_t>, tree,
-				     vec<tree, va_gc> *, vec<tree, va_gc> *);
+				     vec<tree, va_gc> *, vec<tree, va_gc> *,
+				     tree = NULL_TREE);
 
 extern tree resolve_overloaded_builtin (location_t, tree, vec<tree, va_gc> *);
 
diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog
index 96655493ac0..718e5b8b850 100644
--- a/gcc/c/ChangeLog
+++ b/gcc/c/ChangeLog
@@ -1,3 +1,9 @@
+2019-09-27  Richard Sandiford  <richard.sandiford@arm.com>
+
+	* c-typeck.c (build_function_call_vec): Take the original function
+	decl as an optional final parameter.  Pass all built-in calls to
+	check_builtin_function_arguments.
+
 2019-09-20  Eric Botcazou  <ebotcazou@adacore.com>
 
 	PR c/91815
diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c
index d4e12eb93d1..cc13fdc84c8 100644
--- a/gcc/c/c-typeck.c
+++ b/gcc/c/c-typeck.c
@@ -3003,6 +3003,8 @@ inform_declaration (tree decl)
 }
 
 /* Build a function call to function FUNCTION with parameters PARAMS.
+   If FUNCTION is the result of resolving an overloaded target built-in,
+   ORIG_FUNDECL is the original function decl, otherwise it is null.
    ORIGTYPES, if not NULL, is a vector of types; each element is
    either NULL or the original type of the corresponding element in
    PARAMS.  The original type may differ from TREE_TYPE of the
@@ -3013,7 +3015,7 @@ inform_declaration (tree decl)
 tree
 build_function_call_vec (location_t loc, vec<location_t> arg_loc,
 			 tree function, vec<tree, va_gc> *params,
-			 vec<tree, va_gc> *origtypes)
+			 vec<tree, va_gc> *origtypes, tree orig_fundecl)
 {
   tree fntype, fundecl = NULL_TREE;
   tree name = NULL_TREE, result;
@@ -3033,6 +3035,8 @@ build_function_call_vec (location_t loc, vec<location_t> arg_loc,
       if (flag_tm)
 	tm_malloc_replacement (function);
       fundecl = function;
+      if (!orig_fundecl)
+	orig_fundecl = fundecl;
       /* Atomic functions have type checking/casting already done.  They are 
 	 often rewritten and don't match the original parameter list.  */
       if (name && !strncmp (IDENTIFIER_POINTER (name), "__atomic_", 9))
@@ -3110,9 +3114,10 @@ build_function_call_vec (location_t loc, vec<location_t> arg_loc,
   argarray = vec_safe_address (params);
 
   /* Check that arguments to builtin functions match the expectations.  */
-  if (fundecl && fndecl_built_in_p (fundecl, BUILT_IN_NORMAL)
-      && !check_builtin_function_arguments (loc, arg_loc, fundecl, nargs,
-					    argarray))
+  if (fundecl
+      && fndecl_built_in_p (fundecl)
+      && !check_builtin_function_arguments (loc, arg_loc, fundecl,
+					    orig_fundecl, nargs, argarray))
     return error_mark_node;
 
   /* Check that the arguments to the function are valid.  */
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 1d30cef717e..3a3ef9ed250 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,16 @@
+2019-09-27  Richard Sandiford  <richard.sandiford@arm.com>
+
+	* cp-tree.h (build_cxx_call): Take the original function decl
+	as an optional final parameter.
+	(cp_build_function_call_vec): Likewise.
+	* call.c (build_cxx_call): Likewise.  Pass all built-in calls to
+	check_builtin_function_arguments.
+	* typeck.c (build_function_call_vec): Take the original function
+	decl as an optional final parameter and pass it to
+	cp_build_function_call_vec.
+	(cp_build_function_call_vec): Take the original function
+	decl as an optional final parameter and pass it to build_cxx_call.
+
 2019-09-25  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/91877 - ICE with converting member of packed struct.
diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index 45b984ecb11..5ccf3b89682 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -9105,12 +9105,14 @@ maybe_warn_class_memaccess (location_t loc, tree fndecl,
 }
 
 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
+   If FN is the result of resolving an overloaded target built-in,
+   ORIG_FNDECL is the original function decl, otherwise it is null.
    This function performs no overload resolution, conversion, or other
    high-level operations.  */
 
 tree
 build_cxx_call (tree fn, int nargs, tree *argarray,
-		tsubst_flags_t complain)
+		tsubst_flags_t complain, tree orig_fndecl)
 {
   tree fndecl;
 
@@ -9120,11 +9122,13 @@ build_cxx_call (tree fn, int nargs, tree *argarray,
   SET_EXPR_LOCATION (fn, loc);
 
   fndecl = get_callee_fndecl (fn);
+  if (!orig_fndecl)
+    orig_fndecl = fndecl;
 
   /* Check that arguments to builtin functions match the expectations.  */
   if (fndecl
       && !processing_template_decl
-      && fndecl_built_in_p (fndecl, BUILT_IN_NORMAL))
+      && fndecl_built_in_p (fndecl))
     {
       int i;
 
@@ -9134,7 +9138,7 @@ build_cxx_call (tree fn, int nargs, tree *argarray,
 	argarray[i] = maybe_constant_value (argarray[i]);
 
       if (!check_builtin_function_arguments (EXPR_LOCATION (fn), vNULL, fndecl,
-					     nargs, argarray))
+					     orig_fndecl, nargs, argarray))
 	return error_mark_node;
     }
 
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 9c0f3949c68..8fc3fc1f78b 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -6257,7 +6257,8 @@ extern tree perform_direct_initialization_if_possible (tree, tree, bool,
                                                        tsubst_flags_t);
 extern tree in_charge_arg_for_name		(tree);
 extern tree build_cxx_call			(tree, int, tree *,
-						 tsubst_flags_t);
+						 tsubst_flags_t,
+						 tree = NULL_TREE);
 extern bool is_std_init_list			(tree);
 extern bool is_list_ctor			(tree);
 extern void validate_conversion_obstack		(void);
@@ -7391,7 +7392,8 @@ extern tree get_member_function_from_ptrfunc	(tree *, tree, tsubst_flags_t);
 extern tree cp_build_function_call_nary         (tree, tsubst_flags_t, ...)
 						ATTRIBUTE_SENTINEL;
 extern tree cp_build_function_call_vec		(tree, vec<tree, va_gc> **,
-						 tsubst_flags_t);
+						 tsubst_flags_t,
+						 tree = NULL_TREE);
 extern tree build_x_binary_op			(const op_location_t &,
 						 enum tree_code, tree,
 						 enum tree_code, tree,
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index f427c4f4d3e..d549450a605 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -3773,11 +3773,11 @@ build_function_call (location_t /*loc*/,
 tree
 build_function_call_vec (location_t /*loc*/, vec<location_t> /*arg_loc*/,
 			 tree function, vec<tree, va_gc> *params,
-			 vec<tree, va_gc> * /*origtypes*/)
+			 vec<tree, va_gc> * /*origtypes*/, tree orig_function)
 {
   vec<tree, va_gc> *orig_params = params;
   tree ret = cp_build_function_call_vec (function, &params,
-					 tf_warning_or_error);
+					 tf_warning_or_error, orig_function);
 
   /* cp_build_function_call_vec can reallocate PARAMS by adding
      default arguments.  That should never happen here.  Verify
@@ -3818,13 +3818,15 @@ cp_build_function_call_nary (tree function, tsubst_flags_t complain, ...)
   return ret;
 }
 
-/* Build a function call using a vector of arguments.  PARAMS may be
-   NULL if there are no parameters.  This changes the contents of
-   PARAMS.  */
+/* Build a function call using a vector of arguments.
+   If FUNCTION is the result of resolving an overloaded target built-in,
+   ORIG_FNDECL is the original function decl, otherwise it is null.
+   PARAMS may be NULL if there are no parameters.  This changes the
+   contents of PARAMS.  */
 
 tree
 cp_build_function_call_vec (tree function, vec<tree, va_gc> **params,
-			    tsubst_flags_t complain)
+			    tsubst_flags_t complain, tree orig_fndecl)
 {
   tree fntype, fndecl;
   int is_method;
@@ -3949,7 +3951,7 @@ cp_build_function_call_vec (tree function, vec<tree, va_gc> **params,
   bool warned_p = check_function_arguments (input_location, fndecl, fntype,
 					    nargs, argarray, NULL);
 
-  ret = build_cxx_call (function, nargs, argarray, complain);
+  ret = build_cxx_call (function, nargs, argarray, complain, orig_fndecl);
 
   if (warned_p)
     {
diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index 0250cf58e72..a86c210d4fe 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -11567,6 +11567,21 @@ another @code{CALL_EXPR}.
 @var{arglist} really has type @samp{VEC(tree,gc)*}
 @end deftypefn
 
+@deftypefn {Target Hook} bool TARGET_CHECK_BUILTIN_CALL (location_t @var{loc}, vec<location_t> @var{arg_loc}, tree @var{fndecl}, tree @var{orig_fndecl}, unsigned int @var{nargs}, tree *@var{args})
+Perform semantic checking on a call to a machine-specific built-in
+function after its arguments have been constrained to the function
+signature.  Return true if the call is valid, otherwise report an error
+and return false.
+
+This hook is called after @code{TARGET_RESOLVE_OVERLOADED_BUILTIN}.
+The call was originally to built-in function @var{orig_fndecl},
+but after the optional @code{TARGET_RESOLVE_OVERLOADED_BUILTIN}
+step is now to built-in function @var{fndecl}.  @var{loc} is the
+location of the call and @var{args} is an array of function arguments,
+of which there are @var{nargs}.  @var{arg_loc} specifies the location
+of each argument.
+@end deftypefn
+
 @deftypefn {Target Hook} tree TARGET_FOLD_BUILTIN (tree @var{fndecl}, int @var{n_args}, tree *@var{argp}, bool @var{ignore})
 Fold a call to a machine specific built-in function that was set up by
 @samp{TARGET_INIT_BUILTINS}.  @var{fndecl} is the declaration of the
diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in
index 0b77dd8eb46..06dfcda35ab 100644
--- a/gcc/doc/tm.texi.in
+++ b/gcc/doc/tm.texi.in
@@ -7938,6 +7938,8 @@ to by @var{ce_info}.
 
 @hook TARGET_RESOLVE_OVERLOADED_BUILTIN
 
+@hook TARGET_CHECK_BUILTIN_CALL
+
 @hook TARGET_FOLD_BUILTIN
 
 @hook TARGET_GIMPLE_FOLD_BUILTIN
diff --git a/gcc/target.def b/gcc/target.def
index 01609136848..f9446fa05a2 100644
--- a/gcc/target.def
+++ b/gcc/target.def
@@ -2397,6 +2397,24 @@ another @code{CALL_EXPR}.\n\
 @var{arglist} really has type @samp{VEC(tree,gc)*}",
  tree, (unsigned int /*location_t*/ loc, tree fndecl, void *arglist), NULL)
 
+DEFHOOK
+(check_builtin_call,
+ "Perform semantic checking on a call to a machine-specific built-in\n\
+function after its arguments have been constrained to the function\n\
+signature.  Return true if the call is valid, otherwise report an error\n\
+and return false.\n\
+\n\
+This hook is called after @code{TARGET_RESOLVE_OVERLOADED_BUILTIN}.\n\
+The call was originally to built-in function @var{orig_fndecl},\n\
+but after the optional @code{TARGET_RESOLVE_OVERLOADED_BUILTIN}\n\
+step is now to built-in function @var{fndecl}.  @var{loc} is the\n\
+location of the call and @var{args} is an array of function arguments,\n\
+of which there are @var{nargs}.  @var{arg_loc} specifies the location\n\
+of each argument.",
+ bool, (location_t loc, vec<location_t> arg_loc, tree fndecl,
+	tree orig_fndecl, unsigned int nargs, tree *args),
+ NULL)
+
 /* Fold a target-specific builtin to a tree valid for both GIMPLE
    and GENERIC.  */
 DEFHOOK