compile: Fix GNU-IFUNC funcs called from injected code

One could not call IFUNCs (=indirect functions) from the compiled injected
code.  Either it errored with:
	gdb command line:1:1: error: function return type cannot be function

or it just called the IFUNC dispatcher in normal way, returning real function
implementation address instead of the function return value (and thus no
function was called).

gdb/ChangeLog
2015-02-26  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* compile/compile-c-symbols.c (convert_one_symbol, convert_symbol_bmsym)
	(gcc_symbol_address): Call gnu_ifunc_resolve_addr.

gdb/testsuite/ChangeLog
2015-02-26  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gdb.compile/compile-ifunc.c: New file.
	* gdb.compile/compile-ifunc.exp: New file.

gdb/ChangeLog

@@ -1,3 +1,8 @@
+2015-02-26  Jan Kratochvil  <jan.kratochvil@redhat.com>
+
+	* compile/compile-c-symbols.c (convert_one_symbol, convert_symbol_bmsym)
+	(gcc_symbol_address): Call gnu_ifunc_resolve_addr.
+
 2015-02-26  Antoine Tremblay  <antoine.tremblay@ericsson.com>
 
 	* gdb/infcmd.c (print_return_value): use type_to_string to print type.

gdb/compile/compile-c-symbols.c

@@ -187,6 +187,8 @@ convert_one_symbol (struct compile_c_instance *context,
 	case LOC_BLOCK:
 	  kind = GCC_C_SYMBOL_FUNCTION;
 	  addr = BLOCK_START (SYMBOL_BLOCK_VALUE (sym));
+	  if (is_global && TYPE_GNU_IFUNC (SYMBOL_TYPE (sym)))
+	    addr = gnu_ifunc_resolve_addr (target_gdbarch (), addr);
 	  break;
 
 	case LOC_CONST:
@@ -365,6 +367,8 @@ convert_symbol_bmsym (struct compile_c_instance *context,
   gcc_decl decl;
   CORE_ADDR addr;
 
+  addr = MSYMBOL_VALUE_ADDRESS (objfile, msym);
+
   /* Conversion copied from write_exp_msymbol.  */
   switch (MSYMBOL_TYPE (msym))
     {
@@ -376,8 +380,11 @@ convert_symbol_bmsym (struct compile_c_instance *context,
       break;
 
     case mst_text_gnu_ifunc:
-      type = objfile_type (objfile)->nodebug_text_gnu_ifunc_symbol;
+      /* nodebug_text_gnu_ifunc_symbol would cause:
+	 function return type cannot be function  */
+      type = objfile_type (objfile)->nodebug_text_symbol;
       kind = GCC_C_SYMBOL_FUNCTION;
+      addr = gnu_ifunc_resolve_addr (target_gdbarch (), addr);
       break;
 
     case mst_data:
@@ -400,7 +407,6 @@ convert_symbol_bmsym (struct compile_c_instance *context,
     }
 
   sym_type = convert_type (context, type);
-  addr = MSYMBOL_VALUE_ADDRESS (objfile, msym);
   decl = C_CTX (context)->c_ops->build_decl (C_CTX (context),
 					     MSYMBOL_NATURAL_NAME (msym),
 					     kind, sym_type, NULL, addr,
@@ -497,6 +503,8 @@ gcc_symbol_address (void *datum, struct gcc_c_context *gcc_context,
 				"gcc_symbol_address \"%s\": full symbol\n",
 				identifier);
 	  result = BLOCK_START (SYMBOL_BLOCK_VALUE (sym));
+	  if (TYPE_GNU_IFUNC (SYMBOL_TYPE (sym)))
+	    result = gnu_ifunc_resolve_addr (target_gdbarch (), result);
 	  found = 1;
 	}
       else
@@ -512,6 +520,8 @@ gcc_symbol_address (void *datum, struct gcc_c_context *gcc_context,
 				    "symbol\n",
 				    identifier);
 	      result = BMSYMBOL_VALUE_ADDRESS (msym);
+	      if (MSYMBOL_TYPE (msym.minsym) == mst_text_gnu_ifunc)
+		result = gnu_ifunc_resolve_addr (target_gdbarch (), result);
 	      found = 1;
 	    }
 	}

gdb/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2015-02-26  Jan Kratochvil  <jan.kratochvil@redhat.com>
+
+	* gdb.compile/compile-ifunc.c: New file.
+	* gdb.compile/compile-ifunc.exp: New file.
+
 2015-02-26  Antoine Tremblay  <antoine.tremblay@ericsson.com>
 
 	* gdb.base/structs.exp: Check for correct struct on finish.

gdb/testsuite/gdb.compile/compile-ifunc.c

@@ -0,0 +1,46 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2015 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <stdlib.h>
+
+typedef int (*final_t) (int arg);
+
+int
+final (int arg)
+{
+  return arg + 1;
+}
+
+asm (".type gnu_ifunc, %gnu_indirect_function");
+
+final_t
+gnu_ifunc (void)
+{
+  return final;
+}
+
+extern int gnu_ifunc_alias (int arg) __attribute__ ((alias ("gnu_ifunc")));
+
+static int resultvar;
+
+int
+main (void)
+{
+  if (gnu_ifunc_alias (10) != 11)
+    abort ();
+  return resultvar;
+}

gdb/testsuite/gdb.compile/compile-ifunc.exp

@@ -0,0 +1,54 @@
+# Copyright 2015 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+standard_testfile
+
+with_test_prefix "nodebug" {
+
+    if { [prepare_for_testing ${testfile}.exp "$testfile-nodebug" $srcfile {}] } {
+	return -1
+    }
+
+    if ![runto_main] {
+	return -1
+    }
+
+    if {[skip_compile_feature_tests]} {
+	untested "compile command not supported (could not find libcc1 shared library?)"
+	return -1
+    }
+
+    gdb_test_no_output "compile code resultvar = gnu_ifunc (10);"
+
+    gdb_test "p resultvar" " = 11"
+
+}
+
+with_test_prefix "debug" {
+
+    if { [prepare_for_testing ${testfile}.exp "$testfile-debug" $srcfile] } {
+	return -1
+    }
+
+    if ![runto_main] {
+	return -1
+    }
+
+    # gnu_ifunc (10): error: too many arguments to function 'gnu_ifunc'
+    gdb_test_no_output "compile code resultvar = gnu_ifunc_alias (10);"
+
+    gdb_test "p resultvar" " = 11"
+
+}