Enable -Wsuggest-override

I noticed the existence of -Wsuggest-override and so this patch
enables it for gdb.  It found a few spots that could use "override".
Also I went ahead and removed all uses of the "OVERRIDE" macro.

Using override is beneficial because it makes it harder to change a
base class and then forget to change a derived class.

Tested by the buildbot.

ChangeLog
2018-04-27  Tom Tromey  <tom@tromey.com>

	* configure: Rebuild.
	* warning.m4 (AM_GDB_WARNINGS): Add -Wsuggest-override.
	* dwarf2loc.c (class dwarf_evaluate_loc_desc): Use "override", not
	"OVERRIDE".
	(class symbol_needs_eval_context): Likewise.
	* dwarf2read.c (mock_mapped_index::symbol_name_count)
	(mock_mapped_index::symbol_name_at): Use "override".  Remove
	"virtual".
	* dwarf2-frame.c (dwarf_expr_executor::get_addr_index): Use
	"override".
	(class dwarf_expr_executor): Use "override", not "OVERRIDE".
	* aarch64-tdep.c (instruction_reader::read): Use "override".
	(instruction_reader_test::read): Likewise.
	* arm-tdep.c (instruction_reader::read): Use "override".
	(instruction_reader_thumb::read): Likewise.

gdbserver/ChangeLog
2018-04-27  Tom Tromey  <tom@tromey.com>

	* configure: Rebuild.

10 files changed, 67 insertions, 40 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index cd86be7..f6cb82b 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,21 @@
+2018-04-27  Tom Tromey  <tom@tromey.com>
+
+	* configure: Rebuild.
+	* warning.m4 (AM_GDB_WARNINGS): Add -Wsuggest-override.
+	* dwarf2loc.c (class dwarf_evaluate_loc_desc): Use "override", not
+	"OVERRIDE".
+	(class symbol_needs_eval_context): Likewise.
+	* dwarf2read.c (mock_mapped_index::symbol_name_count)
+	(mock_mapped_index::symbol_name_at): Use "override".  Remove
+	"virtual".
+	* dwarf2-frame.c (dwarf_expr_executor::get_addr_index): Use
+	"override".
+	(class dwarf_expr_executor): Use "override", not "OVERRIDE".
+	* aarch64-tdep.c (instruction_reader::read): Use "override".
+	(instruction_reader_test::read): Likewise.
+	* arm-tdep.c (instruction_reader::read): Use "override".
+	(instruction_reader_thumb::read): Likewise.
+
 2018-04-26  Andrzej Kaczmarek  <andrzej.kaczmarek@codecoup.pl>
 
 	PR remote/9665
diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index f08945e..01566b4 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -210,6 +210,7 @@ class instruction_reader : public abstract_instruction_reader
 {
  public:
   ULONGEST read (CORE_ADDR memaddr, int len, enum bfd_endian byte_order)
+    override
   {
     return read_code_unsigned_integer (memaddr, len, byte_order);
   }
@@ -505,6 +506,7 @@ public:
   {}
 
   ULONGEST read (CORE_ADDR memaddr, int len, enum bfd_endian byte_order)
+    override
   {
     SELF_CHECK (len == 4);
     SELF_CHECK (memaddr % 4 == 0);
diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c
index f64df4c..463fcaf 100644
--- a/gdb/arm-tdep.c
+++ b/gdb/arm-tdep.c
@@ -13061,7 +13061,7 @@ public:
 class instruction_reader : public abstract_memory_reader
 {
  public:
-  bool read (CORE_ADDR memaddr, gdb_byte *buf, const size_t len)
+  bool read (CORE_ADDR memaddr, gdb_byte *buf, const size_t len) override
   {
     if (target_read_memory (memaddr, buf, len))
       return false;
@@ -13214,7 +13214,7 @@ public:
     : m_endian (endian), m_insns (insns), m_insns_size (SIZE)
   {}
 
-  bool read (CORE_ADDR memaddr, gdb_byte *buf, const size_t len)
+  bool read (CORE_ADDR memaddr, gdb_byte *buf, const size_t len) override
   {
     SELF_CHECK (len == 4 || len == 2);
     SELF_CHECK (memaddr % 2 == 0);
diff --git a/gdb/configure b/gdb/configure
index 0341b00..f18d78e 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -15365,7 +15365,8 @@ build_warnings="-Wall -Wpointer-arith \
 -Wempty-body -Wunused-but-set-parameter -Wunused-but-set-variable \
 -Wno-sign-compare -Wno-narrowing -Wno-error=maybe-uninitialized \
 -Wno-mismatched-tags \
--Wno-error=deprecated-register"
+-Wno-error=deprecated-register \
+-Wsuggest-override"
 
 case "${host}" in
   *-*-mingw32*)
diff --git a/gdb/dwarf2-frame.c b/gdb/dwarf2-frame.c
index 753ce1f..38367f7 100644
--- a/gdb/dwarf2-frame.c
+++ b/gdb/dwarf2-frame.c
@@ -230,12 +230,12 @@ class dwarf_expr_executor : public dwarf_expr_context
 
   struct frame_info *this_frame;
 
-  CORE_ADDR read_addr_from_reg (int reg) OVERRIDE
+  CORE_ADDR read_addr_from_reg (int reg) override
   {
     return ::read_addr_from_reg (this_frame, reg);
   }
 
-  struct value *get_reg_value (struct type *type, int reg) OVERRIDE
+  struct value *get_reg_value (struct type *type, int reg) override
   {
     struct gdbarch *gdbarch = get_frame_arch (this_frame);
     int regnum = dwarf_reg_to_regnum_or_error (gdbarch, reg);
@@ -243,44 +243,44 @@ class dwarf_expr_executor : public dwarf_expr_context
     return value_from_register (type, regnum, this_frame);
   }
 
-  void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t len) OVERRIDE
+  void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t len) override
   {
     read_memory (addr, buf, len);
   }
 
-  void get_frame_base (const gdb_byte **start, size_t *length) OVERRIDE
+  void get_frame_base (const gdb_byte **start, size_t *length) override
   {
     invalid ("DW_OP_fbreg");
   }
 
   void push_dwarf_reg_entry_value (enum call_site_parameter_kind kind,
 				   union call_site_parameter_u kind_u,
-				   int deref_size) OVERRIDE
+				   int deref_size) override
   {
     invalid ("DW_OP_entry_value");
   }
 
-  CORE_ADDR get_object_address () OVERRIDE
+  CORE_ADDR get_object_address () override
   {
     invalid ("DW_OP_push_object_address");
   }
 
-  CORE_ADDR get_frame_cfa () OVERRIDE
+  CORE_ADDR get_frame_cfa () override
   {
     invalid ("DW_OP_call_frame_cfa");
   }
 
-  CORE_ADDR get_tls_address (CORE_ADDR offset) OVERRIDE
+  CORE_ADDR get_tls_address (CORE_ADDR offset) override
   {
     invalid ("DW_OP_form_tls_address");
   }
 
-  void dwarf_call (cu_offset die_offset) OVERRIDE
+  void dwarf_call (cu_offset die_offset) override
   {
     invalid ("DW_OP_call*");
   }
 
-  CORE_ADDR get_addr_index (unsigned int index)
+  CORE_ADDR get_addr_index (unsigned int index) override
   {
     invalid ("DW_OP_GNU_addr_index");
   }
diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c
index 6c84e4a..243e047 100644
--- a/gdb/dwarf2loc.c
+++ b/gdb/dwarf2loc.c
@@ -557,7 +557,7 @@ class dwarf_evaluate_loc_desc : public dwarf_expr_context
   /* Helper function for dwarf2_evaluate_loc_desc.  Computes the CFA for
      the frame in BATON.  */
 
-  CORE_ADDR get_frame_cfa () OVERRIDE
+  CORE_ADDR get_frame_cfa () override
   {
     return dwarf2_frame_cfa (frame);
   }
@@ -565,14 +565,14 @@ class dwarf_evaluate_loc_desc : public dwarf_expr_context
   /* Helper function for dwarf2_evaluate_loc_desc.  Computes the PC for
      the frame in BATON.  */
 
-  CORE_ADDR get_frame_pc () OVERRIDE
+  CORE_ADDR get_frame_pc () override
   {
     return get_frame_address_in_block (frame);
   }
 
   /* Using the objfile specified in BATON, find the address for the
      current thread's thread-local storage with offset OFFSET.  */
-  CORE_ADDR get_tls_address (CORE_ADDR offset) OVERRIDE
+  CORE_ADDR get_tls_address (CORE_ADDR offset) override
   {
     struct objfile *objfile = dwarf2_per_cu_objfile (per_cu);
 
@@ -582,12 +582,12 @@ class dwarf_evaluate_loc_desc : public dwarf_expr_context
   /* Helper interface of per_cu_dwarf_call for
      dwarf2_evaluate_loc_desc.  */
 
-  void dwarf_call (cu_offset die_offset) OVERRIDE
+  void dwarf_call (cu_offset die_offset) override
   {
     per_cu_dwarf_call (this, die_offset, per_cu);
   }
 
-  struct type *get_base_type (cu_offset die_offset, int size) OVERRIDE
+  struct type *get_base_type (cu_offset die_offset, int size) override
   {
     struct type *result = dwarf2_get_die_type (die_offset, per_cu);
     if (result == NULL)
@@ -600,7 +600,7 @@ class dwarf_evaluate_loc_desc : public dwarf_expr_context
   /* Callback function for dwarf2_evaluate_loc_desc.
      Fetch the address indexed by DW_OP_GNU_addr_index.  */
 
-  CORE_ADDR get_addr_index (unsigned int index) OVERRIDE
+  CORE_ADDR get_addr_index (unsigned int index) override
   {
     return dwarf2_read_addr_index (per_cu, index);
   }
@@ -608,7 +608,7 @@ class dwarf_evaluate_loc_desc : public dwarf_expr_context
   /* Callback function for get_object_address. Return the address of the VLA
      object.  */
 
-  CORE_ADDR get_object_address () OVERRIDE
+  CORE_ADDR get_object_address () override
   {
     if (obj_address == 0)
       error (_("Location address is not set."));
@@ -625,7 +625,7 @@ class dwarf_evaluate_loc_desc : public dwarf_expr_context
 
   void push_dwarf_reg_entry_value (enum call_site_parameter_kind kind,
 				   union call_site_parameter_u kind_u,
-				   int deref_size) OVERRIDE
+				   int deref_size) override
   {
     struct frame_info *caller_frame;
     struct dwarf2_per_cu_data *caller_per_cu;
@@ -666,7 +666,7 @@ class dwarf_evaluate_loc_desc : public dwarf_expr_context
   /* Using the frame specified in BATON, find the location expression
      describing the frame base.  Return a pointer to it in START and
      its length in LENGTH.  */
-  void get_frame_base (const gdb_byte **start, size_t * length) OVERRIDE
+  void get_frame_base (const gdb_byte **start, size_t * length) override
   {
     /* FIXME: cagney/2003-03-26: This code should be using
        get_frame_base_address(), and then implement a dwarf2 specific
@@ -694,14 +694,14 @@ class dwarf_evaluate_loc_desc : public dwarf_expr_context
 
   /* Read memory at ADDR (length LEN) into BUF.  */
 
-  void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t len) OVERRIDE
+  void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t len) override
   {
     read_memory (addr, buf, len);
   }
 
   /* Using the frame specified in BATON, return the value of register
      REGNUM, treated as a pointer.  */
-  CORE_ADDR read_addr_from_reg (int dwarf_regnum) OVERRIDE
+  CORE_ADDR read_addr_from_reg (int dwarf_regnum) override
   {
     struct gdbarch *gdbarch = get_frame_arch (frame);
     int regnum = dwarf_reg_to_regnum_or_error (gdbarch, dwarf_regnum);
@@ -711,7 +711,7 @@ class dwarf_evaluate_loc_desc : public dwarf_expr_context
 
   /* Implement "get_reg_value" callback.  */
 
-  struct value *get_reg_value (struct type *type, int dwarf_regnum) OVERRIDE
+  struct value *get_reg_value (struct type *type, int dwarf_regnum) override
   {
     struct gdbarch *gdbarch = get_frame_arch (frame);
     int regnum = dwarf_reg_to_regnum_or_error (gdbarch, dwarf_regnum);
@@ -2735,7 +2735,7 @@ class symbol_needs_eval_context : public dwarf_expr_context
   struct dwarf2_per_cu_data *per_cu;
 
   /* Reads from registers do require a frame.  */
-  CORE_ADDR read_addr_from_reg (int regnum) OVERRIDE
+  CORE_ADDR read_addr_from_reg (int regnum) override
   {
     needs = SYMBOL_NEEDS_FRAME;
     return 1;
@@ -2744,20 +2744,20 @@ class symbol_needs_eval_context : public dwarf_expr_context
   /* "get_reg_value" callback: Reads from registers do require a
      frame.  */
 
-  struct value *get_reg_value (struct type *type, int regnum) OVERRIDE
+  struct value *get_reg_value (struct type *type, int regnum) override
   {
     needs = SYMBOL_NEEDS_FRAME;
     return value_zero (type, not_lval);
   }
 
   /* Reads from memory do not require a frame.  */
-  void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t len) OVERRIDE
+  void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t len) override
   {
     memset (buf, 0, len);
   }
 
   /* Frame-relative accesses do require a frame.  */
-  void get_frame_base (const gdb_byte **start, size_t *length) OVERRIDE
+  void get_frame_base (const gdb_byte **start, size_t *length) override
   {
     static gdb_byte lit0 = DW_OP_lit0;
 
@@ -2768,20 +2768,20 @@ class symbol_needs_eval_context : public dwarf_expr_context
   }
 
   /* CFA accesses require a frame.  */
-  CORE_ADDR get_frame_cfa () OVERRIDE
+  CORE_ADDR get_frame_cfa () override
   {
     needs = SYMBOL_NEEDS_FRAME;
     return 1;
   }
 
-  CORE_ADDR get_frame_pc () OVERRIDE
+  CORE_ADDR get_frame_pc () override
   {
     needs = SYMBOL_NEEDS_FRAME;
     return 1;
   }
 
   /* Thread-local accesses require registers, but not a frame.  */
-  CORE_ADDR get_tls_address (CORE_ADDR offset) OVERRIDE
+  CORE_ADDR get_tls_address (CORE_ADDR offset) override
   {
     if (needs <= SYMBOL_NEEDS_REGISTERS)
       needs = SYMBOL_NEEDS_REGISTERS;
@@ -2791,7 +2791,7 @@ class symbol_needs_eval_context : public dwarf_expr_context
   /* Helper interface of per_cu_dwarf_call for
      dwarf2_loc_desc_get_symbol_read_needs.  */
 
-  void dwarf_call (cu_offset die_offset) OVERRIDE
+  void dwarf_call (cu_offset die_offset) override
   {
     per_cu_dwarf_call (this, die_offset, per_cu);
   }
@@ -2801,7 +2801,7 @@ class symbol_needs_eval_context : public dwarf_expr_context
 
   void push_dwarf_reg_entry_value (enum call_site_parameter_kind kind,
 				   union call_site_parameter_u kind_u,
-				   int deref_size) OVERRIDE
+				   int deref_size) override
   {
     needs = SYMBOL_NEEDS_FRAME;
 
@@ -2811,7 +2811,7 @@ class symbol_needs_eval_context : public dwarf_expr_context
 
   /* DW_OP_GNU_addr_index doesn't require a frame.  */
 
-   CORE_ADDR get_addr_index (unsigned int index) OVERRIDE
+   CORE_ADDR get_addr_index (unsigned int index) override
    {
      /* Nothing to do.  */
      return 1;
@@ -2819,7 +2819,7 @@ class symbol_needs_eval_context : public dwarf_expr_context
 
    /* DW_OP_push_object_address has a frame already passed through.  */
 
-   CORE_ADDR get_object_address () OVERRIDE
+   CORE_ADDR get_object_address () override
    {
      /* Nothing to do.  */
      return 1;
diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index 4207e4c..9eb98b2 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -4577,13 +4577,13 @@ public:
   DISABLE_COPY_AND_ASSIGN (mock_mapped_index);
 
   /* Return the number of names in the symbol table.  */
-  virtual size_t symbol_name_count () const
+  size_t symbol_name_count () const override
   {
     return m_symbol_table.size ();
   }
 
   /* Get the name of the symbol at IDX in the symbol table.  */
-  virtual const char *symbol_name_at (offset_type idx) const
+  const char *symbol_name_at (offset_type idx) const override
   {
     return m_symbol_table[idx];
   }
diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 2fbc5ba..0cdb1c2 100644
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,3 +1,7 @@
+2018-04-27  Tom Tromey  <tom@tromey.com>
+
+	* configure: Rebuild.
+
 2018-04-23  Tom Tromey  <tom@tromey.com>
 
 	* configure: Rebuild.
diff --git a/gdb/gdbserver/configure b/gdb/gdbserver/configure
index 5b3dee4..22b4c8a 100755
--- a/gdb/gdbserver/configure
+++ b/gdb/gdbserver/configure
@@ -7172,7 +7172,8 @@ build_warnings="-Wall -Wpointer-arith \
 -Wempty-body -Wunused-but-set-parameter -Wunused-but-set-variable \
 -Wno-sign-compare -Wno-narrowing -Wno-error=maybe-uninitialized \
 -Wno-mismatched-tags \
--Wno-error=deprecated-register"
+-Wno-error=deprecated-register \
+-Wsuggest-override"
 
 case "${host}" in
   *-*-mingw32*)
diff --git a/gdb/warning.m4 b/gdb/warning.m4
index 3cfae65..f176a32 100644
--- a/gdb/warning.m4
+++ b/gdb/warning.m4
@@ -42,7 +42,8 @@ build_warnings="-Wall -Wpointer-arith \
 -Wempty-body -Wunused-but-set-parameter -Wunused-but-set-variable \
 -Wno-sign-compare -Wno-narrowing -Wno-error=maybe-uninitialized \
 -Wno-mismatched-tags \
--Wno-error=deprecated-register"
+-Wno-error=deprecated-register \
+-Wsuggest-override"
 
 case "${host}" in
   *-*-mingw32*)