1 files changed, 143 insertions, 8 deletions

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index f1c58faa035..4bfe2fa8c1d 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -7188,6 +7188,31 @@ ix86_set_indirect_branch_type (tree fndecl)
       else
 	cfun->machine->indirect_branch_type = ix86_indirect_branch;
     }
+
+  if (cfun->machine->function_return_type == indirect_branch_unset)
+    {
+      tree attr = lookup_attribute ("function_return",
+				    DECL_ATTRIBUTES (fndecl));
+      if (attr != NULL)
+	{
+	  tree args = TREE_VALUE (attr);
+	  if (args == NULL)
+	    gcc_unreachable ();
+	  tree cst = TREE_VALUE (args);
+	  if (strcmp (TREE_STRING_POINTER (cst), "keep") == 0)
+	    cfun->machine->function_return_type = indirect_branch_keep;
+	  else if (strcmp (TREE_STRING_POINTER (cst), "thunk") == 0)
+	    cfun->machine->function_return_type = indirect_branch_thunk;
+	  else if (strcmp (TREE_STRING_POINTER (cst), "thunk-inline") == 0)
+	    cfun->machine->function_return_type = indirect_branch_thunk_inline;
+	  else if (strcmp (TREE_STRING_POINTER (cst), "thunk-extern") == 0)
+	    cfun->machine->function_return_type = indirect_branch_thunk_extern;
+	  else
+	    gcc_unreachable ();
+	}
+      else
+	cfun->machine->function_return_type = ix86_function_return;
+    }
 }
 
 /* Establish appropriate back-end context for processing the function
@@ -11990,8 +12015,12 @@ static int indirect_thunks_bnd_used;
 /* Fills in the label name that should be used for the indirect thunk.  */
 
 static void
-indirect_thunk_name (char name[32], int regno, bool need_bnd_p)
+indirect_thunk_name (char name[32], int regno, bool need_bnd_p,
+		     bool ret_p)
 {
+  if (regno >= 0 && ret_p)
+    gcc_unreachable ();
+
   if (USE_HIDDEN_LINKONCE)
     {
       const char *bnd = need_bnd_p ? "_bnd" : "";
@@ -12006,7 +12035,10 @@ indirect_thunk_name (char name[32], int regno, bool need_bnd_p)
 		   bnd, reg_prefix, reg_names[regno]);
 	}
       else
-	sprintf (name, "__x86_indirect_thunk%s", bnd);
+	{
+	  const char *ret = ret_p ? "return" : "indirect";
+	  sprintf (name, "__x86_%s_thunk%s", ret, bnd);
+	}
     }
   else
     {
@@ -12019,10 +12051,20 @@ indirect_thunk_name (char name[32], int regno, bool need_bnd_p)
 	}
       else
 	{
-	  if (need_bnd_p)
-	    ASM_GENERATE_INTERNAL_LABEL (name, "LITB", 0);
+	  if (ret_p)
+	    {
+	      if (need_bnd_p)
+		ASM_GENERATE_INTERNAL_LABEL (name, "LRTB", 0);
+	      else
+		ASM_GENERATE_INTERNAL_LABEL (name, "LRT", 0);
+	    }
 	  else
-	    ASM_GENERATE_INTERNAL_LABEL (name, "LIT", 0);
+	    {
+	      if (need_bnd_p)
+		ASM_GENERATE_INTERNAL_LABEL (name, "LITB", 0);
+	      else
+		ASM_GENERATE_INTERNAL_LABEL (name, "LIT", 0);
+	    }
 	}
     }
 }
@@ -12117,7 +12159,7 @@ output_indirect_thunk_function (bool need_bnd_p, int regno)
   tree decl;
 
   /* Create __x86_indirect_thunk/__x86_indirect_thunk_bnd.  */
-  indirect_thunk_name (name, regno, need_bnd_p);
+  indirect_thunk_name (name, regno, need_bnd_p, false);
   decl = build_decl (BUILTINS_LOCATION, FUNCTION_DECL,
 		     get_identifier (name),
 		     build_function_type_list (void_type_node, NULL_TREE));
@@ -12160,6 +12202,35 @@ output_indirect_thunk_function (bool need_bnd_p, int regno)
 	ASM_OUTPUT_LABEL (asm_out_file, name);
       }
 
+  if (regno < 0)
+    {
+      /* Create alias for __x86.return_thunk/__x86.return_thunk_bnd.  */
+      char alias[32];
+
+      indirect_thunk_name (alias, regno, need_bnd_p, true);
+      ASM_OUTPUT_DEF (asm_out_file, alias, name);
+#if TARGET_MACHO
+      if (TARGET_MACHO)
+	{
+	  fputs ("\t.weak_definition\t", asm_out_file);
+	  assemble_name (asm_out_file, alias);
+	  fputs ("\n\t.private_extern\t", asm_out_file);
+	  assemble_name (asm_out_file, alias);
+	  putc ('\n', asm_out_file);
+	}
+#else
+      if (USE_HIDDEN_LINKONCE)
+	{
+	  fputs ("\t.globl\t", asm_out_file);
+	  assemble_name (asm_out_file, alias);
+	  putc ('\n', asm_out_file);
+	  fputs ("\t.hidden\t", asm_out_file);
+	  assemble_name (asm_out_file, alias);
+	  putc ('\n', asm_out_file);
+	}
+#endif
+    }
+
   DECL_INITIAL (decl) = make_node (BLOCK);
   current_function_decl = decl;
   allocate_struct_function (decl, false);
@@ -28760,7 +28831,7 @@ ix86_output_indirect_branch_via_reg (rtx call_op, bool sibcall_p)
 	  else
 	    indirect_thunks_used |= 1 << i;
 	}
-      indirect_thunk_name (thunk_name_buf, regno, need_bnd_p);
+      indirect_thunk_name (thunk_name_buf, regno, need_bnd_p, false);
       thunk_name = thunk_name_buf;
     }
   else
@@ -28869,7 +28940,7 @@ ix86_output_indirect_branch_via_push (rtx call_op, const char *xasm,
 	  else
 	    indirect_thunk_needed = true;
 	}
-      indirect_thunk_name (thunk_name_buf, regno, need_bnd_p);
+      indirect_thunk_name (thunk_name_buf, regno, need_bnd_p, false);
       thunk_name = thunk_name_buf;
     }
   else
@@ -29004,6 +29075,46 @@ ix86_output_indirect_jmp (rtx call_op, bool ret_p)
     return "%!jmp\t%A0";
 }
 
+/* Output function return.  CALL_OP is the jump target.  Add a REP
+   prefix to RET if LONG_P is true and function return is kept.  */
+
+const char *
+ix86_output_function_return (bool long_p)
+{
+  if (cfun->machine->function_return_type != indirect_branch_keep)
+    {
+      char thunk_name[32];
+      bool need_bnd_p = ix86_bnd_prefixed_insn_p (current_output_insn);
+
+      if (cfun->machine->function_return_type
+	  != indirect_branch_thunk_inline)
+	{
+	  bool need_thunk = (cfun->machine->function_return_type
+			     == indirect_branch_thunk);
+	  indirect_thunk_name (thunk_name, -1, need_bnd_p, true);
+	  if (need_bnd_p)
+	    {
+	      indirect_thunk_bnd_needed |= need_thunk;
+	      fprintf (asm_out_file, "\tbnd jmp\t%s\n", thunk_name);
+	    }
+	  else
+	    {
+	      indirect_thunk_needed |= need_thunk;
+	      fprintf (asm_out_file, "\tjmp\t%s\n", thunk_name);
+	    }
+	}
+      else
+	output_indirect_thunk (need_bnd_p, -1);
+
+      return "";
+    }
+
+  if (!long_p || ix86_bnd_prefixed_insn_p (current_output_insn))
+    return "%!ret";
+
+  return "rep%; ret";
+}
+
 /* Output the assembly for a call instruction.  */
 
 const char *
@@ -42075,6 +42186,28 @@ ix86_handle_fndecl_attribute (tree *node, tree name, tree args, int,
 	}
     }
 
+  if (is_attribute_p ("function_return", name))
+    {
+      tree cst = TREE_VALUE (args);
+      if (TREE_CODE (cst) != STRING_CST)
+	{
+	  warning (OPT_Wattributes,
+		   "%qE attribute requires a string constant argument",
+		   name);
+	  *no_add_attrs = true;
+	}
+      else if (strcmp (TREE_STRING_POINTER (cst), "keep") != 0
+	       && strcmp (TREE_STRING_POINTER (cst), "thunk") != 0
+	       && strcmp (TREE_STRING_POINTER (cst), "thunk-inline") != 0
+	       && strcmp (TREE_STRING_POINTER (cst), "thunk-extern") != 0)
+	{
+	  warning (OPT_Wattributes,
+		   "argument to %qE attribute is not "
+		   "(keep|thunk|thunk-inline|thunk-extern)", name);
+	  *no_add_attrs = true;
+	}
+    }
+
   return NULL_TREE;
 }
 
@@ -46385,6 +46518,8 @@ static const struct attribute_spec ix86_attribute_table[] =
     ix86_handle_no_caller_saved_registers_attribute, false },
   { "indirect_branch", 1, 1, true, false, false,
     ix86_handle_fndecl_attribute, false },
+  { "function_return", 1, 1, true, false, false,
+    ix86_handle_fndecl_attribute, false },
 
   /* End element.  */
   { NULL,        0, 0, false, false, false, NULL, false }