Add unit test to gdbarch methods register_to_value and value_to_register

This patch adds one unit test for gdbarch methods register_to_value and
value_to_register.  The test pass different combinations of {regnu, type}
to gdbarch_register_to_value and gdbarch_value_to_register.  In order
to do the test, add a new function create_new_frame to create a fake
frame.  It can be improved after we converted frame_info to class.

In order to isolate regcache (from target_ops operations on writing
registers, like target_store_registers), the sub-class of regcache in the
test override raw_write.  Also, in order to get the right regcache from
get_thread_arch_aspace_regcache, the sub-class of regcache inserts itself
to current_regcache.

Suppose I incorrectly modified the size of buffer as below,

@@ -1228,7 +1228,7 @@ ia64_register_to_value (struct frame_info *frame, int regnum,
                        int *optimizedp, int *unavailablep)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  gdb_byte in[MAX_REGISTER_SIZE];
+  gdb_byte in[1];

   /* Convert to TYPE.  */
   if (!get_frame_register_bytes (frame, regnum, 0,

build GDB with "-fsanitize=address" and run unittest.exp, asan can detect
such error

==2302==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7fff98193870 at pc 0xbd55ea bp 0x7fff981935a0 sp 0x7fff98193598
WRITE of size 16 at 0x7fff98193870 thread T0
    #0 0xbd55e9 in frame_register_unwind(frame_info*, int, int*, int*, lval_type*, unsigned long*, int*, unsigned char*) /home/yao/SourceCode/gnu/gdb/git/gdb/frame.c:1119
    #1 0xbd58c8 in frame_register(frame_info*, int, int*, int*, lval_type*, unsigned long*, int*, unsigned char*) /home/yao/SourceCode/gnu/gdb/git/gdb/frame.c:1147
    #2 0xbd6e25 in get_frame_register_bytes(frame_info*, int, unsigned long, int, unsigned char*, int*, int*) /home/yao/SourceCode/gnu/gdb/git/gdb/frame.c:1427
    #3 0x70080a in ia64_register_to_value /home/yao/SourceCode/gnu/gdb/git/gdb/ia64-tdep.c:1236
    #4 0xbf570e in gdbarch_register_to_value(gdbarch*, frame_info*, int, type*, unsigned char*, int*, int*) /home/yao/SourceCode/gnu/gdb/git/gdb/gdbarch.c:2619
    #5 0xc05975 in register_to_value_test /home/yao/SourceCode/gnu/gdb/git/gdb/gdbarch-selftests.c:131

Or, even if GDB is not built with asan, GDB just crashes.

*** stack smashing detected ***: ./gdb terminated
Aborted (core dumped)

gdb:

2017-05-24  Yao Qi  <[email protected]>

	* Makefile.in (SFILES): Add gdbarch-selftests.c.
	(COMMON_OBS): Add gdbarch-selftests.o.
	* frame.c [GDB_SELF_TESTS] (create_new_frame): New function.
	* frame.h [GDB_SELF_TESTS] (create_new_frame): Declare.
	* gdbarch-selftests.c: New file.
	* regcache.h (regcache) <~regcache>: Mark it virtual if
	GDB_SELF_TEST.
	<raw_write>: Likewise.

gdb/ChangeLog

@@ -1,3 +1,14 @@
+2017-05-24  Yao Qi  <[email protected]>
+
+	* Makefile.in (SFILES): Add gdbarch-selftests.c.
+	(COMMON_OBS): Add gdbarch-selftests.o.
+	* frame.c [GDB_SELF_TESTS] (create_new_frame): New function.
+	* frame.h [GDB_SELF_TESTS] (create_new_frame): Declare.
+	* gdbarch-selftests.c: New file.
+	* regcache.h (regcache) <~regcache>: Mark it virtual if
+	GDB_SELF_TEST.
+	<raw_write>: Likewise.
+
 2017-05-24  Yao Qi  <[email protected]>
 
 	* regcache.c (current_regcache): Change it to

gdb/Makefile.in

@@ -1106,6 +1106,7 @@ SFILES = \
 	gdb_obstack.c \
 	gdb_usleep.c \
 	gdbarch.c \
+	gdbarch-selftests.c \
 	gdbtypes.c \
 	gnu-v2-abi.c \
 	gnu-v3-abi.c \
@@ -1719,6 +1720,7 @@ COMMON_OBS = $(DEPFILES) $(CONFIG_OBS) $(YYOBJ) \
 	gdb_usleep.o \
 	gdb_vecs.o \
 	gdbarch.o \
+	gdbarch-selftests.o \
 	gdbtypes.o \
 	gnu-v2-abi.o \
 	gnu-v3-abi.o \

gdb/frame.c

@@ -1704,6 +1704,23 @@ select_frame (struct frame_info *fi)
     }
 }
 
+#if GDB_SELF_TEST
+struct frame_info *
+create_test_frame (struct regcache *regcache)
+{
+  struct frame_info *this_frame = XCNEW (struct frame_info);
+
+  sentinel_frame = create_sentinel_frame (NULL, regcache);
+  sentinel_frame->prev = this_frame;
+  sentinel_frame->prev_p = 1;;
+  this_frame->prev_arch.p = 1;
+  this_frame->prev_arch.arch = get_regcache_arch (regcache);
+  this_frame->next = sentinel_frame;
+
+  return this_frame;
+}
+#endif
+
 /* Create an arbitrary (i.e. address specified by user) or innermost frame.
    Always returns a non-NULL value.  */
 

gdb/frame.h

@@ -833,6 +833,14 @@ extern struct frame_info *deprecated_safe_get_selected_frame (void);
 
 extern struct frame_info *create_new_frame (CORE_ADDR base, CORE_ADDR pc);
 
+#if GDB_SELF_TEST
+
+/* Create a frame for unit test.  Its next frame is sentinel frame,
+   created from REGCACHE.  */
+
+extern struct frame_info *create_test_frame (struct regcache *regcache);
+#endif
+
 /* Return true if the frame unwinder for frame FI is UNWINDER; false
    otherwise.  */
 

gdb/gdbarch-selftests.c

@@ -0,0 +1,156 @@
+/* Self tests for gdbarch for GDB, the GNU debugger.
+
+   Copyright (C) 2017 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   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 "defs.h"
+#if GDB_SELF_TEST
+#include "selftest.h"
+#include "selftest-arch.h"
+#include "inferior.h"
+
+namespace selftests {
+
+/* A read-write regcache which doesn't write the target.  */
+
+class regcache_test : public regcache
+{
+public:
+  explicit regcache_test (struct gdbarch *gdbarch)
+    : regcache (gdbarch, NULL, false)
+  {
+    set_ptid (inferior_ptid);
+
+    current_regcache.push_front (this);
+  }
+
+  void raw_write (int regnum, const gdb_byte *buf) override
+  {
+    raw_set_cached_value (regnum, buf);
+  }
+};
+
+/* Test gdbarch methods register_to_value and value_to_register.  */
+
+static void
+register_to_value_test (struct gdbarch *gdbarch)
+{
+  const struct builtin_type *builtin = builtin_type (gdbarch);
+  struct type *types[] =
+    {
+      builtin->builtin_void,
+      builtin->builtin_char,
+      builtin->builtin_short,
+      builtin->builtin_int,
+      builtin->builtin_long,
+      builtin->builtin_signed_char,
+      builtin->builtin_unsigned_short,
+      builtin->builtin_unsigned_int,
+      builtin->builtin_unsigned_long,
+      builtin->builtin_float,
+      builtin->builtin_double,
+      builtin->builtin_long_double,
+      builtin->builtin_complex,
+      builtin->builtin_double_complex,
+      builtin->builtin_string,
+      builtin->builtin_bool,
+      builtin->builtin_long_long,
+      builtin->builtin_unsigned_long_long,
+      builtin->builtin_int8,
+      builtin->builtin_uint8,
+      builtin->builtin_int16,
+      builtin->builtin_uint16,
+      builtin->builtin_int32,
+      builtin->builtin_uint32,
+      builtin->builtin_int64,
+      builtin->builtin_uint64,
+      builtin->builtin_int128,
+      builtin->builtin_uint128,
+      builtin->builtin_char16,
+      builtin->builtin_char32,
+    };
+
+  current_inferior()->gdbarch = gdbarch;
+
+  struct regcache *regcache = new regcache_test (gdbarch);
+  struct frame_info *frame = create_test_frame (regcache);
+  const int num_regs = (gdbarch_num_regs (gdbarch)
+			+ gdbarch_num_pseudo_regs (gdbarch));
+
+  SELF_CHECK (regcache == get_current_regcache ());
+
+  /* Test gdbarch methods register_to_value and value_to_register with
+     different combinations of register numbers and types.  */
+  for (const auto &type : types)
+    {
+      for (auto regnum = 0; regnum < num_regs; regnum++)
+	{
+	  if (gdbarch_convert_register_p (gdbarch, regnum, type))
+	    {
+	      std::vector<gdb_byte> expected (TYPE_LENGTH (type), 0);
+
+	      if (TYPE_CODE (type) == TYPE_CODE_FLT)
+		{
+		  DOUBLEST d = 1.25;
+
+		  /* Generate valid float format.  */
+		  floatformat_from_doublest (floatformat_from_type (type),
+					     &d, expected.data ());
+		}
+	      else
+		{
+		  for (auto j = 0; j < expected.size (); j++)
+		    expected[j] = (regnum + j) % 16;
+		}
+
+	      gdbarch_value_to_register (gdbarch, frame, regnum, type,
+					 expected.data ());
+
+	      /* Allocate two bytes more for overflow check.  */
+	      std::vector<gdb_byte> buf (TYPE_LENGTH (type) + 2, 0);
+	      int optim, unavail, ok;
+
+	      /* Set the fingerprint in the last two bytes.  */
+	      buf [TYPE_LENGTH (type)]= 'w';
+	      buf [TYPE_LENGTH (type) + 1]= 'l';
+	      ok = gdbarch_register_to_value (gdbarch, frame, regnum, type,
+					      buf.data (), &optim, &unavail);
+
+	      SELF_CHECK (ok);
+	      SELF_CHECK (!optim);
+	      SELF_CHECK (!unavail);
+
+	      SELF_CHECK (buf[TYPE_LENGTH (type)] == 'w');
+	      SELF_CHECK (buf[TYPE_LENGTH (type) + 1] == 'l');
+
+	      for (auto k = 0; k < TYPE_LENGTH(type); k++)
+		SELF_CHECK (buf[k] == expected[k]);
+	    }
+	}
+    }
+}
+
+} // namespace selftests
+#endif /* GDB_SELF_TEST */
+
+void
+_initialize_gdbarch_selftests (void)
+{
+#if GDB_SELF_TEST
+  register_self_test_foreach_arch (selftests::register_to_value_test);
+#endif
+}

gdb/regcache.h

@@ -250,6 +250,11 @@ class regcache
   regcache (const regcache &) = delete;
   void operator= (const regcache &) = delete;
 
+  /* class regcache is only extended in unit test, so only mark it
+     virtual when selftest is enabled.  */
+#if GDB_SELF_TEST
+  virtual
+#endif
   ~regcache ()
   {
     xfree (m_registers);
@@ -269,6 +274,12 @@ class regcache
   void cooked_write (int regnum, const gdb_byte *buf);
 
   enum register_status raw_read (int regnum, gdb_byte *buf);
+
+  /* class regcache is only extended in unit test, so only mark it
+     virtual when selftest is enabled.  */
+#if GDB_SELF_TEST
+  virtual
+#endif
   void raw_write (int regnum, const gdb_byte *buf);
 
   enum register_status raw_read_signed (int regnum, LONGEST *val);