Disassembly unit test: disassemble one instruction

This patch adds one unit test, which disassemble one instruction for
every gdbarch if available.  The test needs one valid instruction of
each gdbarch, and most of them are got from breakpoint instruction.
For the rest gdbarch whose breakpoint instruction isn't a valid
instruction, I copy one instruction from the gas/testsuite/gas/
directory.

I get the valid instruction of most gdbarch except ia64, mep, mips,
tic6x, and xtensa.  People familiar with these arch should be easy
to extend the test.

In order to achieve "do the unit test for every gdbarch", I add
selftest-arch.[c,h], so that we can register a function pointer,
which has one argument gdbarch.  selftest.c will iterate over all
gdbarches to call the registered function pointer.

gdb:

2017-01-26  Yao Qi  <yao.qi@linaro.org>

	* Makefile.in (SFILES): Add disasm-selftests.c and
	selftest-arch.c.
	(COMMON_OBS): Add disasm-selftests.o and selftest-arch.o.
	* disasm-selftests.c: New file.
	* selftest-arch.c: New file.
	* selftest-arch.h: New file.

1 files changed, 179 insertions, 0 deletions

diff --git a/gdb/disasm-selftests.c b/gdb/disasm-selftests.c
new file mode 100644
index 0000000..3d68abd
--- /dev/null
+++ b/gdb/disasm-selftests.c
@@ -0,0 +1,179 @@
+/* Self tests for disassembler 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"
+#include "disasm.h"
+
+#if GDB_SELF_TEST
+#include "selftest.h"
+#include "selftest-arch.h"
+
+namespace selftests {
+
+/* Test disassembly of one instruction.  */
+
+static void
+print_one_insn_test (struct gdbarch *gdbarch)
+{
+  size_t len = 0;
+  const gdb_byte *insn = NULL;
+
+  switch (gdbarch_bfd_arch_info (gdbarch)->arch)
+    {
+    case bfd_arch_bfin:
+      /* M3.L = 0xe117 */
+      static const gdb_byte bfin_insn[] = {0x17, 0xe1, 0xff, 0xff};
+
+      insn = bfin_insn;
+      len = sizeof (bfin_insn);
+      break;
+    case bfd_arch_arm:
+      /* mov     r0, #0 */
+      static const gdb_byte arm_insn[] = {0x0, 0x0, 0xa0, 0xe3};
+
+      insn = arm_insn;
+      len = sizeof (arm_insn);
+      break;
+    case bfd_arch_ia64:
+    case bfd_arch_mep:
+    case bfd_arch_mips:
+    case bfd_arch_tic6x:
+    case bfd_arch_xtensa:
+      return;
+    case bfd_arch_s390:
+      /* nopr %r7 */
+      static const gdb_byte s390_insn[] = {0x07, 0x07};
+
+      insn = s390_insn;
+      len = sizeof (s390_insn);
+      break;
+    case bfd_arch_xstormy16:
+      /* nop */
+      static const gdb_byte xstormy16_insn[] = {0x0, 0x0};
+
+      insn = xstormy16_insn;
+      len = sizeof (xstormy16_insn);
+      break;
+    case bfd_arch_arc:
+      /* PR 21003 */
+      if (gdbarch_bfd_arch_info (gdbarch)->mach == bfd_mach_arc_arc601)
+	return;
+      /* fall through */
+    case bfd_arch_nios2:
+    case bfd_arch_score:
+      /* nios2 and score need to know the current instruction to select
+	 breakpoint instruction.  Give the breakpoint instruction kind
+	 explicitly.  */
+      int bplen;
+      insn = gdbarch_sw_breakpoint_from_kind (gdbarch, 4, &bplen);
+      len = bplen;
+      break;
+    default:
+      {
+	/* Test disassemble breakpoint instruction.  */
+	CORE_ADDR pc = 0;
+	int kind = gdbarch_breakpoint_kind_from_pc (gdbarch, &pc);
+	int bplen;
+
+	insn = gdbarch_sw_breakpoint_from_kind (gdbarch, kind, &bplen);
+	len = bplen;
+
+	break;
+      }
+    }
+  SELF_CHECK (len > 0);
+
+  /* Test gdb_disassembler for a given gdbarch by reading data from a
+     pre-allocated buffer.  If you want to see the disassembled
+     instruction printed to gdb_stdout, set verbose to true.  */
+
+  class gdb_disassembler_test : public gdb_disassembler
+  {
+  public:
+
+    const bool verbose = false;
+
+    explicit gdb_disassembler_test (struct gdbarch *gdbarch,
+				    const gdb_byte *insn,
+				    size_t len)
+      : gdb_disassembler (gdbarch,
+			  (verbose ? gdb_stdout : null_stream ()),
+			  gdb_disassembler_test::read_memory),
+	m_insn (insn), m_len (len)
+    {
+    }
+
+    int
+    print_insn (CORE_ADDR memaddr)
+    {
+      if (verbose)
+	{
+	  fprintf_unfiltered (stream (), "%s ",
+			      gdbarch_bfd_arch_info (arch ())->arch_name);
+	}
+
+      int len = gdb_disassembler::print_insn (memaddr);
+
+      if (verbose)
+	fprintf_unfiltered (stream (), "\n");
+
+      return len;
+    }
+
+  private:
+    /* A buffer contain one instruction.  */
+    const gdb_byte *m_insn;
+
+    /* Length of the buffer.  */
+    size_t m_len;
+
+    static int read_memory (bfd_vma memaddr, gdb_byte *myaddr,
+			    unsigned int len, struct disassemble_info *info)
+    {
+      gdb_disassembler_test *self
+	= static_cast<gdb_disassembler_test *>(info->application_data);
+
+      /* The disassembler in opcodes may read more data than one
+	 instruction.  Supply infinite consecutive copies
+	 of the same instruction.  */
+      for (size_t i = 0; i < len; i++)
+	myaddr[i] = self->m_insn[(memaddr + i) % self->m_len];
+
+      return 0;
+    }
+  };
+
+  gdb_disassembler_test di (gdbarch, insn, len);
+
+  SELF_CHECK (di.print_insn (0) == len);
+}
+
+} // namespace selftests
+#endif /* GDB_SELF_TEST */
+
+/* Suppress warning from -Wmissing-prototypes.  */
+extern initialize_file_ftype _initialize_disasm_selftests;
+
+void
+_initialize_disasm_selftests (void)
+{
+#if GDB_SELF_TEST
+  register_self_test_foreach_arch (selftests::print_one_insn_test);
+#endif
+}