diff mbox

compile: Fix GNU-IFUNC funcs called from injected code

Message ID 20150224190720.GA32497@host1.jankratochvil.net
State New
Headers show

Commit Message

Jan Kratochvil Feb. 24, 2015, 7:07 p.m. UTC
Hi,

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).

It is a pre-requisite for Phil's later 'compile print' code which calls
memcpy() from the injected code.


No regressions on {x86_64,x86_64-m32,i686}-fedora23pre-linux-gnu.


Thanks,
Jan
gdb/ChangeLog
2015-02-24  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
2015-02-24  Jan Kratochvil  <jan.kratochvil@redhat.com>

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

Patch

diff --git a/gdb/compile/compile-c-symbols.c b/gdb/compile/compile-c-symbols.c
index 6562f05..ba6a229 100644
--- a/gdb/compile/compile-c-symbols.c
+++ b/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;
 	    }
 	}
diff --git a/gdb/testsuite/gdb.compile/compile-ifunc.c b/gdb/testsuite/gdb.compile/compile-ifunc.c
new file mode 100644
index 0000000..e5cee77
--- /dev/null
+++ b/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;
+}
diff --git a/gdb/testsuite/gdb.compile/compile-ifunc.exp b/gdb/testsuite/gdb.compile/compile-ifunc.exp
new file mode 100644
index 0000000..9e83c46
--- /dev/null
+++ b/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
+
+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
+}
+
+with_test_prefix "nodebug" {
+
+    gdb_test_no_output "compile code resultvar = gnu_ifunc (10);"
+
+    gdb_test "p resultvar" " = 11"
+
+}
+
+if { [prepare_for_testing ${testfile}.exp "$testfile-debug" $srcfile] } {
+    return -1
+}
+
+if ![runto_main] {
+    return -1
+}
+
+with_test_prefix "debug" {
+
+    # 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" "debug: p resultvar"
+
+}