gdb/
2009-11-24  Jan Kratochvil  <jan.kratochvil@redhat.com>

	Transparent GNU-IFUNCs support.
	* elfread.c (record_minimal_symbol): Apply also for mst_text_gnu_ifunc.
	(elf_symtab_read): Set also mst_text_gnu_ifunc.
	* gdbtypes.c (init_type): Support TYPE_FLAG_GNU_IFUNC.
	(gdbtypes_post_init): Initialize builtin_func_func_ptr.
	(objfile_type): Initialize nodebug_text_gnu_ifunc_symbol.
	* gdbtypes.h (enum type_flag_value <TYPE_FLAG_GNU_IFUNC>)
	(TYPE_GNU_IFUNC, struct main_type <flag_gnu_ifunc>)
	(struct builtin_type <builtin_func_func_ptr>)
	(struct objfile_type <nodebug_text_gnu_ifunc_symbol>): New.
	* infcall.c (find_function_addr <TYPE_GNU_IFUNC (ftype)>): New.
	* minsyms.c (lookup_minimal_symbol_text, prim_record_minimal_symbol)
	(find_solib_trampoline_target): Support also mst_text_gnu_ifunc.
	(in_gnu_ifunc_stub): New.
	* parse.c (write_exp_msymbol <mst_text_gnu_ifunc>): New.
	* solib-svr4.c (svr4_in_dynsym_resolve_code): Call also
	in_gnu_ifunc_stub.
	* symmisc.c (dump_msymbols <mst_text_gnu_ifunc>): New.
	* symtab.c (search_symbols): Support also mst_text_gnu_ifunc.
	* symtab.h (enum minimal_symbol_type <mst_text_gnu_ifunc>)
	(in_gnu_ifunc_stub): New.
	* linespec.c: Include infcall.h.
	(minsym_found <MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc>): New.

gdb/testsuite/
2009-11-24  Jan Kratochvil  <jan.kratochvil@redhat.com>

	Transparent GNU-IFUNCs support.
	* gdb.base/gnu-ifunc-lib.c, gdb.base/gnu-ifunc.c,
	gdb.base/gnu-ifunc.exp: New.

Index: gdb-7.0/gdb/elfread.c
===================================================================
--- gdb-7.0.orig/gdb/elfread.c	2009-11-25 10:24:45.000000000 +0100
+++ gdb-7.0/gdb/elfread.c	2009-11-25 10:25:50.000000000 +0100
@@ -168,7 +168,8 @@ record_minimal_symbol (char *name, CORE_
 {
   struct gdbarch *gdbarch = get_objfile_arch (objfile);
 
-  if (ms_type == mst_text || ms_type == mst_file_text)
+  if (ms_type == mst_text || ms_type == mst_file_text
+      || ms_type == mst_text_gnu_ifunc)
     address = gdbarch_smash_text_address (gdbarch, address);
 
   return prim_record_minimal_symbol_and_info
@@ -373,7 +374,10 @@ elf_symtab_read (struct objfile *objfile
 	    {
 	      if (sym->flags & (BSF_GLOBAL | BSF_WEAK))
 		{
-		  ms_type = mst_text;
+		  if (sym->flags & BSF_GNU_INDIRECT_FUNCTION)
+		    ms_type = mst_text_gnu_ifunc;
+		  else
+		    ms_type = mst_text;
 		}
 	      else if ((sym->name[0] == '.' && sym->name[1] == 'L')
 		       || ((sym->flags & BSF_LOCAL)
Index: gdb-7.0/gdb/gdbtypes.c
===================================================================
--- gdb-7.0.orig/gdb/gdbtypes.c	2009-11-25 10:24:47.000000000 +0100
+++ gdb-7.0/gdb/gdbtypes.c	2009-11-25 10:24:56.000000000 +0100
@@ -1904,6 +1904,8 @@ init_type (enum type_code code, int leng
     TYPE_NOTTEXT (type) = 1;
   if (flags & TYPE_FLAG_FIXED_INSTANCE)
     TYPE_FIXED_INSTANCE (type) = 1;
+  if (flags & TYPE_FLAG_GNU_IFUNC)
+    TYPE_GNU_IFUNC (type) = 1;
 
   if (name)
     TYPE_NAME (type) = obsavestring (name, strlen (name),
@@ -3762,6 +3764,8 @@ gdbtypes_post_init (struct gdbarch *gdba
     = lookup_pointer_type (builtin_type->builtin_void);
   builtin_type->builtin_func_ptr
     = lookup_pointer_type (lookup_function_type (builtin_type->builtin_void));
+  builtin_type->builtin_func_func_ptr
+    = lookup_pointer_type (lookup_function_type (builtin_type->builtin_func_ptr));
 
   /* This type represents a GDB internal function.  */
   builtin_type->internal_fn
@@ -3878,6 +3882,11 @@ objfile_type (struct objfile *objfile)
 		 "<text variable, no debug info>", objfile);
   TYPE_TARGET_TYPE (objfile_type->nodebug_text_symbol)
     = objfile_type->builtin_int;
+  objfile_type->nodebug_text_gnu_ifunc_symbol
+    = init_type (TYPE_CODE_FUNC, 1, TYPE_FLAG_GNU_IFUNC,
+		 "<text gnu-ifunc variable, no debug info>", objfile);
+  TYPE_TARGET_TYPE (objfile_type->nodebug_text_gnu_ifunc_symbol)
+    = objfile_type->nodebug_text_symbol;
   objfile_type->nodebug_data_symbol
     = init_type (TYPE_CODE_INT,
 		 gdbarch_int_bit (gdbarch) / HOST_CHAR_BIT, 0,
Index: gdb-7.0/gdb/gdbtypes.h
===================================================================
--- gdb-7.0.orig/gdb/gdbtypes.h	2009-11-25 10:24:48.000000000 +0100
+++ gdb-7.0/gdb/gdbtypes.h	2009-11-25 10:25:17.000000000 +0100
@@ -187,6 +187,7 @@ enum type_flag_value
   TYPE_FLAG_FIXED_INSTANCE = (1 << 15),
   TYPE_FLAG_STUB_SUPPORTED = (1 << 16),
   TYPE_FLAG_NOTTEXT = (1 << 17),
+  TYPE_FLAG_GNU_IFUNC = (1 << 18),
 
   /* Used for error-checking.  */
   TYPE_FLAG_MIN = TYPE_FLAG_UNSIGNED
@@ -292,6 +293,12 @@ enum type_instance_flag_value
 
 #define TYPE_NOTTEXT(t)		(TYPE_MAIN_TYPE (t)->flag_nottext)
 
+/* Currently used only for TYPE_CODE_FUNC where specifies the real function
+   address is returned by this function call.  TYPE_TARGET_TYPE determines the
+   final returned function type to be presented to user.  */
+
+#define TYPE_GNU_IFUNC(t)	(TYPE_MAIN_TYPE (t)->flag_gnu_ifunc)
+
 /* Type owner.  If TYPE_OBJFILE_OWNED is true, the type is owned by
    the objfile retrieved as TYPE_OBJFILE.  Otherweise, the type is
    owned by an architecture; TYPE_OBJFILE is NULL in this case.  */
@@ -427,6 +434,7 @@ struct main_type
   unsigned int flag_vector : 1;
   unsigned int flag_stub_supported : 1;
   unsigned int flag_nottext : 1;
+  unsigned int flag_gnu_ifunc : 1;
   unsigned int flag_fixed_instance : 1;
   unsigned int flag_objfile_owned : 1;
   unsigned int flag_discardable : 1;
@@ -1144,6 +1152,10 @@ struct builtin_type
      (*) () can server as a generic function pointer.  */
   struct type *builtin_func_ptr;
 
+  /* `pointer to function returning pointer to function (returning void)' type.
+     The final void return type is not significant for it.  */
+  struct type *builtin_func_func_ptr;
+
 
   /* Special-purpose types.  */
 
@@ -1186,6 +1198,7 @@ struct objfile_type
 
   /* Types used for symbols with no debug information.  */
   struct type *nodebug_text_symbol;
+  struct type *nodebug_text_gnu_ifunc_symbol;
   struct type *nodebug_data_symbol;
   struct type *nodebug_unknown_symbol;
   struct type *nodebug_tls_symbol;
Index: gdb-7.0/gdb/infcall.c
===================================================================
--- gdb-7.0.orig/gdb/infcall.c	2009-11-25 10:24:45.000000000 +0100
+++ gdb-7.0/gdb/infcall.c	2009-11-25 10:24:56.000000000 +0100
@@ -286,6 +286,27 @@ find_function_addr (struct value *functi
   else
     error (_("Invalid data type for function to be called."));
 
+  if (TYPE_GNU_IFUNC (ftype))
+    {
+      struct type *func_func_ptr;
+
+      funaddr += gdbarch_deprecated_function_start_offset (gdbarch);
+
+      /* Cast FUNADDR to drop TYPE_GNU_IFUNC and being able to call gnu-ifunc
+	 FUNADDR without causing deadlock by this block of code.  */
+
+      func_func_ptr = builtin_type (gdbarch)->builtin_func_func_ptr;
+      function = value_from_pointer (func_func_ptr, funaddr);
+
+      /* gnu-ifuncs have no arguments.  */
+      function = call_function_by_hand (function, 0, NULL);
+
+      funaddr = value_as_address (function);
+
+      /* This is `int' as the return type of the final function.  */
+      value_type = TYPE_TARGET_TYPE (value_type);
+    }
+
   if (retval_type != NULL)
     *retval_type = value_type;
   return funaddr + gdbarch_deprecated_function_start_offset (gdbarch);
Index: gdb-7.0/gdb/linespec.c
===================================================================
--- gdb-7.0.orig/gdb/linespec.c	2009-11-25 10:24:45.000000000 +0100
+++ gdb-7.0/gdb/linespec.c	2009-11-25 10:24:56.000000000 +0100
@@ -40,6 +40,7 @@
 #include "interps.h"
 #include "mi/mi-cmds.h"
 #include "target.h"
+#include "infcall.h"
 
 /* We share this one with symtab.c, but it is not exported widely. */
 
@@ -1875,6 +1876,22 @@ minsym_found (int funfirstline, struct m
   pc = gdbarch_convert_from_func_ptr_addr (gdbarch,
                                            values.sals[0].pc,
                                            &current_target);
+
+  /* Call gnu-ifunc to resolve breakpoint at its returned function.  */
+  if (MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc)
+    {
+      struct type *func_func_ptr;
+      struct value *function;
+
+      func_func_ptr = builtin_type (gdbarch)->builtin_func_func_ptr;
+      function = value_from_pointer (func_func_ptr, pc);
+
+      /* gnu-ifuncs have no arguments.  */
+      function = call_function_by_hand (function, 0, NULL);
+
+      pc = value_as_address (function);
+    }
+
   if (pc != values.sals[0].pc)
     values.sals[0] = find_pc_sect_line (pc, NULL, 0);
 
Index: gdb-7.0/gdb/minsyms.c
===================================================================
--- gdb-7.0.orig/gdb/minsyms.c	2009-11-25 10:24:47.000000000 +0100
+++ gdb-7.0/gdb/minsyms.c	2009-11-25 10:24:56.000000000 +0100
@@ -331,8 +331,9 @@ lookup_minimal_symbol_text (const char *
 	       msymbol = msymbol->hash_next)
 	    {
 	      if (strcmp (SYMBOL_LINKAGE_NAME (msymbol), name) == 0 &&
-		  (MSYMBOL_TYPE (msymbol) == mst_text ||
-		   MSYMBOL_TYPE (msymbol) == mst_file_text))
+		  (MSYMBOL_TYPE (msymbol) == mst_text
+		   || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc
+		   || MSYMBOL_TYPE (msymbol) == mst_file_text))
 		{
 		  switch (MSYMBOL_TYPE (msymbol))
 		    {
@@ -699,6 +700,16 @@ lookup_minimal_symbol_by_pc (CORE_ADDR p
 {
   return lookup_minimal_symbol_by_pc_section (pc, NULL);
 }
+
+/* Return non-zero iff PC is in function implementing gnu-ifunc selection.  */
+
+int
+in_gnu_ifunc_stub (CORE_ADDR pc)
+{
+  struct minimal_symbol *msymbol = lookup_minimal_symbol_by_pc (pc);
+
+  return msymbol && MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc;
+}
 
 
 /* Return leading symbol character for a BFD. If BFD is NULL,
@@ -738,6 +749,7 @@ prim_record_minimal_symbol (const char *
   switch (ms_type)
     {
     case mst_text:
+    case mst_text_gnu_ifunc:
     case mst_file_text:
     case mst_solib_trampoline:
       section = SECT_OFF_TEXT (objfile);
@@ -1184,7 +1196,8 @@ find_solib_trampoline_target (struct fra
     {
       ALL_MSYMBOLS (objfile, msymbol)
       {
-	if (MSYMBOL_TYPE (msymbol) == mst_text
+	if ((MSYMBOL_TYPE (msymbol) == mst_text
+	    || MSYMBOL_TYPE (msymbol) == mst_text_gnu_ifunc)
 	    && strcmp (SYMBOL_LINKAGE_NAME (msymbol),
 		       SYMBOL_LINKAGE_NAME (tsymbol)) == 0)
 	  return SYMBOL_VALUE_ADDRESS (msymbol);
Index: gdb-7.0/gdb/parse.c
===================================================================
--- gdb-7.0.orig/gdb/parse.c	2009-11-25 10:24:47.000000000 +0100
+++ gdb-7.0/gdb/parse.c	2009-11-25 10:26:16.000000000 +0100
@@ -517,6 +517,11 @@ write_exp_msymbol (struct minimal_symbol
 	write_exp_elt_type (objfile_type (objfile)->nodebug_text_symbol);
       break;
 
+    case mst_text_gnu_ifunc:
+      write_exp_elt_type (objfile_type (objfile)
+					       ->nodebug_text_gnu_ifunc_symbol);
+      break;
+
     case mst_data:
     case mst_file_data:
     case mst_bss:
Index: gdb-7.0/gdb/solib-svr4.c
===================================================================
--- gdb-7.0.orig/gdb/solib-svr4.c	2009-11-25 10:24:49.000000000 +0100
+++ gdb-7.0/gdb/solib-svr4.c	2009-11-25 10:26:41.000000000 +0100
@@ -1242,7 +1242,8 @@ svr4_in_dynsym_resolve_code (CORE_ADDR p
 {
   return ((pc >= interp_text_sect_low && pc < interp_text_sect_high)
 	  || (pc >= interp_plt_sect_low && pc < interp_plt_sect_high)
-	  || in_plt_section (pc, NULL));
+	  || in_plt_section (pc, NULL)
+	  || in_gnu_ifunc_stub (pc));
 }
 
 /* Given an executable's ABFD and target, compute the entry-point
Index: gdb-7.0/gdb/symmisc.c
===================================================================
--- gdb-7.0.orig/gdb/symmisc.c	2009-11-25 10:24:47.000000000 +0100
+++ gdb-7.0/gdb/symmisc.c	2009-11-25 10:24:56.000000000 +0100
@@ -287,6 +287,9 @@ dump_msymbols (struct objfile *objfile, 
 	case mst_text:
 	  ms_type = 'T';
 	  break;
+	case mst_text_gnu_ifunc:
+	  ms_type = 'i';
+	  break;
 	case mst_solib_trampoline:
 	  ms_type = 'S';
 	  break;
Index: gdb-7.0/gdb/symtab.c
===================================================================
--- gdb-7.0.orig/gdb/symtab.c	2009-11-25 10:24:47.000000000 +0100
+++ gdb-7.0/gdb/symtab.c	2009-11-25 10:24:56.000000000 +0100
@@ -3155,7 +3155,7 @@ search_symbols (char *regexp, domain_enu
   {mst_file_data, mst_solib_trampoline, mst_abs, mst_unknown};
   static enum minimal_symbol_type types4[]
   =
-  {mst_file_bss, mst_text, mst_abs, mst_unknown};
+  {mst_file_bss, mst_text_gnu_ifunc, mst_abs, mst_unknown};
   enum minimal_symbol_type ourtype;
   enum minimal_symbol_type ourtype2;
   enum minimal_symbol_type ourtype3;
Index: gdb-7.0/gdb/symtab.h
===================================================================
--- gdb-7.0.orig/gdb/symtab.h	2009-11-25 10:24:45.000000000 +0100
+++ gdb-7.0/gdb/symtab.h	2009-11-25 10:24:56.000000000 +0100
@@ -275,6 +275,8 @@ enum minimal_symbol_type
 {
   mst_unknown = 0,		/* Unknown type, the default */
   mst_text,			/* Generally executable instructions */
+  mst_text_gnu_ifunc,		/* Executable code returning address
+				   of executable code */
   mst_data,			/* Generally initialized data */
   mst_bss,			/* Generally uninitialized data */
   mst_abs,			/* Generally absolute (nonrelocatable) */
@@ -1149,6 +1151,8 @@ extern struct minimal_symbol *lookup_min
 
 extern struct minimal_symbol *lookup_minimal_symbol_by_pc (CORE_ADDR);
 
+extern int in_gnu_ifunc_stub (CORE_ADDR pc);
+
 extern struct minimal_symbol
   *lookup_minimal_symbol_by_pc_section (CORE_ADDR, struct obj_section *);
 
Index: gdb-7.0/gdb/testsuite/gdb.base/gnu-ifunc-lib.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ gdb-7.0/gdb/testsuite/gdb.base/gnu-ifunc-lib.c	2009-11-25 10:24:56.000000000 +0100
@@ -0,0 +1,45 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2009 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 <assert.h>
+
+typedef int (*final_t) (int arg);
+
+static int
+final (int arg)
+{
+  return arg + 1;
+}
+
+static volatile int gnu_ifunc_initialized;
+
+void
+gnu_ifunc_pre (void)
+{
+  assert (!gnu_ifunc_initialized);
+}
+
+final_t gnu_ifuncX (void) asm ("gnu_ifunc");
+asm (".type gnu_ifunc, @gnu_indirect_function");
+
+final_t
+gnu_ifuncX (void)
+{
+  gnu_ifunc_initialized = 1;
+
+  return final;
+}
Index: gdb-7.0/gdb/testsuite/gdb.base/gnu-ifunc.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ gdb-7.0/gdb/testsuite/gdb.base/gnu-ifunc.c	2009-11-25 10:24:56.000000000 +0100
@@ -0,0 +1,36 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2009 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 <assert.h>
+
+extern int gnu_ifunc (int arg);
+extern void gnu_ifunc_pre (void);
+
+int
+main (void)
+{
+  int i;
+
+  gnu_ifunc_pre ();
+  
+  i = gnu_ifunc (1);	/* break-at-call */
+  assert (i == 2);
+
+  gnu_ifunc (2);	/* break-at-nextcall */
+
+  return 0;	/* break-at-exit */
+}
Index: gdb-7.0/gdb/testsuite/gdb.base/gnu-ifunc.exp
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ gdb-7.0/gdb/testsuite/gdb.base/gnu-ifunc.exp	2009-11-25 10:24:56.000000000 +0100
@@ -0,0 +1,72 @@
+# Copyright (C) 2009 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/>.
+
+if {[skip_shlib_tests]} {
+    return 0
+}
+
+set testfile "gnu-ifunc"
+set srcfile ${testfile}.c
+set binfile ${objdir}/${subdir}/${testfile}
+
+set libfile "${testfile}-lib"
+set libsrc ${libfile}.c
+set lib_so ${objdir}/${subdir}/${libfile}.so
+
+set lib_opts [list debug]
+set exec_opts [list debug shlib=$lib_so]
+
+if [get_compiler_info ${binfile}] {
+    return -1
+}
+
+if { [gdb_compile_shlib ${srcdir}/${subdir}/$libsrc $lib_so $lib_opts] != ""
+     || [gdb_compile ${srcdir}/${subdir}/$srcfile $binfile executable $exec_opts] != ""} {
+    untested "Could not compile either $libsrc or $srcfile."
+    return -1
+}
+
+# Start with a fresh gdb.
+
+clean_restart $testfile
+gdb_load_shlibs ${lib_so}
+
+if ![runto_main] then {
+    fail "Can't run to main"
+    return 1;
+}
+
+gdb_breakpoint [gdb_get_line_number "break-at-nextcall"]
+
+gdb_breakpoint [gdb_get_line_number "break-at-call"]
+gdb_continue_to_breakpoint "break-at-call" ".*break-at-call.*"
+
+# Test GDB will automatically indirect the call.
+
+gdb_test "p gnu_ifunc (3)" " = 4"
+
+# Test GDB will skip the gnu_ifunc resolver on first call.
+
+gdb_test "step" "\r\nfinal .*"
+
+# Test GDB will not break before the final chosen implementation.
+
+gdb_continue_to_breakpoint "break-at-nextcall" ".*break-at-nextcall.*"
+
+gdb_breakpoint "gnu_ifunc"
+
+gdb_continue_to_breakpoint "nextcall gnu_ifunc"
+
+gdb_test "frame" "#0 +final \\(.*" "nextcall gnu_ifunc skipped"