[PATCH] Fix ifunc and resolver (PR ipa/81213).

["Martin Liška" <mliska@suse.cz>]

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Hello.

Following patch does refactoring of make_resolver_func where ifunc
alias and resolver were probably confused.

Patch can bootstrap on ppc64le-redhat-linux and survives regression tests.
i386.exp tests work on x86_64-linux-gnu.

Ready to be installed?
Martin

gcc/ChangeLog:

2017-06-29  Martin Liska  <mliska@suse.cz>

	PR ipa/81213
	* config/i386/i386.c (make_resolver_func): Do complete
	refactoring of the function.

gcc/testsuite/ChangeLog:

2017-06-29  Martin Liska  <mliska@suse.cz>

	PR ipa/81213
	* gcc.target/i386/pr81213.c: New test.
---
 gcc/config/i386/i386.c                  | 37 ++++++++++++++++-----------------
 gcc/testsuite/gcc.target/i386/pr81213.c | 19 +++++++++++++++++
 2 files changed, 37 insertions(+), 19 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr81213.c



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diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index 9d53a6c869c..e90ae249b96 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -33816,30 +33816,30 @@ ix86_get_function_versions_dispatcher (void *decl)
 }
 
 /* Make the resolver function decl to dispatch the versions of
-   a multi-versioned function,  DEFAULT_DECL.  Create an
+   a multi-versioned function,  DEFAULT_DECL.  IFUNC_ALIAS_DECL is
+   ifunc alias that will point to the created resolver.  Create an
    empty basic block in the resolver and store the pointer in
    EMPTY_BB.  Return the decl of the resolver function.  */
 
 static tree
 make_resolver_func (const tree default_decl,
-		    const tree dispatch_decl,
+		    const tree ifunc_alias_decl,
 		    basic_block *empty_bb)
 {
   char *resolver_name;
   tree decl, type, decl_name, t;
-  bool is_uniq = false;
 
   /* IFUNC's have to be globally visible.  So, if the default_decl is
      not, then the name of the IFUNC should be made unique.  */
   if (TREE_PUBLIC (default_decl) == 0)
-    is_uniq = true;
+    {
+      char *ifunc_name = make_unique_name (default_decl, "ifunc", true);
+      symtab->change_decl_assembler_name (ifunc_alias_decl,
+					  get_identifier (ifunc_name));
+      XDELETEVEC (ifunc_name);
+    }
 
-  /* Append the filename to the resolver function if the versions are
-     not externally visible.  This is because the resolver function has
-     to be externally visible for the loader to find it.  So, appending
-     the filename will prevent conflicts with a resolver function from
-     another module which is based on the same version name.  */
-  resolver_name = make_unique_name (default_decl, "resolver", is_uniq);
+  resolver_name = make_unique_name (default_decl, "resolver", false);
 
   /* The resolver function should return a (void *). */
   type = build_function_type_list (ptr_type_node, NULL_TREE);
@@ -33852,13 +33852,12 @@ make_resolver_func (const tree default_decl,
   TREE_USED (decl) = 1;
   DECL_ARTIFICIAL (decl) = 1;
   DECL_IGNORED_P (decl) = 0;
-  /* IFUNC resolvers have to be externally visible.  */
-  TREE_PUBLIC (decl) = 1;
+  TREE_PUBLIC (decl) = 0;
   DECL_UNINLINABLE (decl) = 1;
 
   /* Resolver is not external, body is generated.  */
   DECL_EXTERNAL (decl) = 0;
-  DECL_EXTERNAL (dispatch_decl) = 0;
+  DECL_EXTERNAL (ifunc_alias_decl) = 0;
 
   DECL_CONTEXT (decl) = NULL_TREE;
   DECL_INITIAL (decl) = make_node (BLOCK);
@@ -33889,14 +33888,14 @@ make_resolver_func (const tree default_decl,
 
   pop_cfun ();
 
-  gcc_assert (dispatch_decl != NULL);
-  /* Mark dispatch_decl as "ifunc" with resolver as resolver_name.  */
-  DECL_ATTRIBUTES (dispatch_decl) 
-    = make_attribute ("ifunc", resolver_name, DECL_ATTRIBUTES (dispatch_decl));
+  gcc_assert (ifunc_alias_decl != NULL);
+  /* Mark ifunc_alias_decl as "ifunc" with resolver as resolver_name.  */
+  DECL_ATTRIBUTES (ifunc_alias_decl)
+    = make_attribute ("ifunc", resolver_name,
+		      DECL_ATTRIBUTES (ifunc_alias_decl));
 
   /* Create the alias for dispatch to resolver here.  */
-  /*cgraph_create_function_alias (dispatch_decl, decl);*/
-  cgraph_node::create_same_body_alias (dispatch_decl, decl);
+  cgraph_node::create_same_body_alias (ifunc_alias_decl, decl);
   XDELETEVEC (resolver_name);
   return decl;
 }
diff --git a/gcc/testsuite/gcc.target/i386/pr81213.c b/gcc/testsuite/gcc.target/i386/pr81213.c
new file mode 100644
index 00000000000..13e15d5fef0
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr81213.c
@@ -0,0 +1,19 @@
+/* PR ipa/81214.  */
+/* { dg-do compile } */
+/* { dg-require-ifunc "" } */
+
+__attribute__((target_clones("avx","arch=slm","arch=core-avx2","default")))
+static int
+foo ()
+{
+  return -2;
+}
+
+int main()
+{
+  return foo();
+}
+
+/* { dg-final { scan-assembler "\t.globl\tfoo\\..*\\.ifunc" } } */
+/* { dg-final { scan-assembler "foo.resolver:" } } */
+/* { dg-final { scan-assembler "foo\\..*\\.ifunc, @gnu_indirect_function" } } */