[PATCH] Reject target_clones attribute in functions that can't be cloned (PR middle-end/84723)

[Jakub Jelinek <jakub at redhat dot com>]

Hi!

The following testcases show various reasons why a function definition
with target_clones attribute can't be cloned; instead of ICEing because
node->create_version_clone_with_body returns NULL and we dereference it,
this patch just diagnoses those and ignores the attribute.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

Martin Sebor said he wants to work on attribute exclusion, in that case
the error messages in pr84723-{1,4,5}.c would be adjusted if needed and
      const char *reason = NULL;
      if (lookup_attribute ("noclone", DECL_ATTRIBUTES (node->decl)))
	reason = G_("function %q+F can never be copied "
		    "because it has %<noclone%> attribute");
      else
	reason = copy_forbidden (DECL_STRUCT_FUNCTION (node->decl));
could be replaced just with
      const char *reason = copy_forbidden (DECL_STRUCT_FUNCTION (node->decl));
but attribute exclusions can't really help for the cases where cloning
is refused because of other reasons.

2018-03-06  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/84723
	* multiple_target.c: Include tree-inline.h and intl.h.
	(expand_target_clones): Diagnose and fail if node->definition and
	!tree_versionable_function_p (node->decl).

	* gcc.target/i386/pr84723-1.c: New test.
	* gcc.target/i386/pr84723-2.c: New test.
	* gcc.target/i386/pr84723-3.c: New test.
	* gcc.target/i386/pr84723-4.c: New test.
	* gcc.target/i386/pr84723-5.c: New test.

--- gcc/multiple_target.c.jj	2018-01-03 10:19:54.956533925 +0100
+++ gcc/multiple_target.c	2018-03-06 11:46:09.327627941 +0100
@@ -36,6 +36,8 @@ along with GCC; see the file COPYING3.
 #include "pretty-print.h"
 #include "gimple-iterator.h"
 #include "gimple-walk.h"
+#include "tree-inline.h"
+#include "intl.h"
 
 /* Walker callback that replaces all FUNCTION_DECL of a function that's
    going to be versioned.  */
@@ -312,6 +314,22 @@ expand_target_clones (struct cgraph_node
       return false;
     }
 
+  if (node->definition
+      && !tree_versionable_function_p (node->decl))
+    {
+      error_at (DECL_SOURCE_LOCATION (node->decl),
+		"clones for %<target_clones%> attribute cannot be created");
+      const char *reason = NULL;
+      if (lookup_attribute ("noclone", DECL_ATTRIBUTES (node->decl)))
+	reason = G_("function %q+F can never be copied "
+		    "because it has %<noclone%> attribute");
+      else
+	reason = copy_forbidden (DECL_STRUCT_FUNCTION (node->decl));
+      if (reason)
+	inform (DECL_SOURCE_LOCATION (node->decl), reason, node->decl);
+      return false;
+    }
+
   char *attr_str = XNEWVEC (char, attr_len);
   int attrnum = get_attr_str (arglist, attr_str);
   char **attrs = XNEWVEC (char *, attrnum);
--- gcc/testsuite/gcc.target/i386/pr84723-1.c.jj	2018-03-06 12:00:17.533367738 +0100
+++ gcc/testsuite/gcc.target/i386/pr84723-1.c	2018-03-06 11:52:15.831511845 +0100
@@ -0,0 +1,11 @@
+/* PR middle-end/84723 */
+/* { dg-do compile } */
+/* { dg-require-ifunc } */
+/* { dg-options "-O2" } */
+
+__attribute__((target_clones ("avx", "default")))
+__attribute__((noclone))
+void
+foo (void)	/* { dg-error "clones for .target_clones. attribute cannot be created" } */
+{		/* { dg-message "function .foo. can never be copied because it has .noclone. attribute" "" { target *-*-* } .-1 } */
+}
--- gcc/testsuite/gcc.target/i386/pr84723-2.c.jj	2018-03-06 12:00:21.019367631 +0100
+++ gcc/testsuite/gcc.target/i386/pr84723-2.c	2018-03-06 11:50:30.458545226 +0100
@@ -0,0 +1,13 @@
+/* PR middle-end/84723 */
+/* { dg-do compile } */
+/* { dg-require-ifunc } */
+/* { dg-options "-O2" } */
+
+__attribute__((target_clones ("avx", "default")))
+void
+foo (void)	/* { dg-error "clones for .target_clones. attribute cannot be created" } */
+{		/* { dg-message "function .foo. can never be copied because it saves address of local label in a static variable" "" { target *-*-* } .-1 } */
+  static void *p = &&lab;
+  asm volatile ("" : "+m" (p) : : "memory");
+lab:;
+}
--- gcc/testsuite/gcc.target/i386/pr84723-3.c.jj	2018-03-06 12:00:24.397367531 +0100
+++ gcc/testsuite/gcc.target/i386/pr84723-3.c	2018-03-06 11:50:57.274536736 +0100
@@ -0,0 +1,17 @@
+/* PR middle-end/84723 */
+/* { dg-do compile } */
+/* { dg-require-ifunc } */
+/* { dg-options "-O2" } */
+
+__attribute__((target_clones ("avx", "default")))
+int
+foo (int x)	/* { dg-error "clones for .target_clones. attribute cannot be created" } */
+{		/* { dg-message "function .foo. can never be copied because it receives a non-local goto" "" { target *-*-* } .-1 } */
+  __label__ lab;
+  __attribute__((noinline)) void bar () { goto lab; }
+  if (x == 5)
+    bar ();
+  x++;
+lab:;
+  return x;
+}
--- gcc/testsuite/gcc.target/i386/pr84723-4.c.jj	2018-03-06 12:00:17.533367738 +0100
+++ gcc/testsuite/gcc.target/i386/pr84723-4.c	2018-03-06 11:52:15.831511845 +0100
@@ -0,0 +1,11 @@
+/* PR middle-end/84723 */
+/* { dg-do compile } */
+/* { dg-require-ifunc } */
+/* { dg-options "-O2" } */
+
+__attribute__((target_clones ("avx", "default")))
+__attribute__((naked))
+void
+foo (void)	/* { dg-error "clones for .target_clones. attribute cannot be created" } */
+{		/* { dg-message "function .foo. can never be copied because it has .noclone. attribute" "" { target *-*-* } .-1 } */
+}
--- gcc/testsuite/gcc.target/i386/pr84723-5.c.jj	2018-03-06 12:00:17.533367738 +0100
+++ gcc/testsuite/gcc.target/i386/pr84723-5.c	2018-03-06 11:52:15.831511845 +0100
@@ -0,0 +1,11 @@
+/* PR middle-end/84723 */
+/* { dg-do compile } */
+/* { dg-require-ifunc } */
+/* { dg-options "-O2" } */
+
+__attribute__((target_clones ("avx", "default")))
+__attribute__((noipa))
+void
+foo (void)	/* { dg-error "clones for .target_clones. attribute cannot be created" } */
+{		/* { dg-message "function .foo. can never be copied because it has .noclone. attribute" "" { target *-*-* } .-1 } */
+}

	Jakub