Convert dwarf_expr_context_funcs to methods

This patch converts the function pointers in dwarf_expr_context_funcs
into methods on dwarf_expr_context, and then updates the various
implementations and callers to follow.

NB this patch uses "override" (which caught a couple of renaming bugs
during development) -- but this is C++11, so this patch at least has
to wait for Pedro's patch that adds the OVERRIDE macro.

After this patch it would be possible to do one more, that makes
various members of dwarf_expr_context "protected"; but I haven't done
this.

2016-10-21  Tom Tromey  <tom@tromey.com>

	* dwarf2loc.c (struct dwarf_expr_context_funcs): Don't declare.
	(dwarf_expr_read_addr_from_reg, dwarf_expr_get_reg_value)
	(dwarf_expr_read_mem, dwarf_expr_frame_base): Rename; turn into
	methods.
	(get_frame_pc_for_per_cu_dwarf_call): New function.
	(dwarf_expr_frame_cfa, dwarf_expr_frame_pc)
	(dwarf_expr_tls_address): Rename; turn into methods.
	(per_cu_dwarf_call): Remove arguments.  Use
	get_frame_pc_for_per_cu_dwarf_call.
	(dwarf_evaluate_loc_desc): New class.
	(dwarf_expr_dwarf_call, dwarf_expr_context)
	(dwarf_expr_push_dwarf_reg_entry_value)
	(dwarf_expr_get_addr_index, dwarf_expr_get_obj_addr): Rename; turn
	into methods.
	(dwarf_expr_ctx_funcs): Remove.
	(dwarf2_evaluate_loc_desc_full): Update.
	(dwarf2_locexpr_baton_eval): Update.
	(symbol_needs_eval_context): New class.
	(symbol_needs_read_addr_from_reg, symbol_needs_get_reg_value)
	(symbol_needs_read_mem, symbol_needs_frame_base)
	(symbol_needs_frame_cfa, symbol_needs_tls_address)
	(symbol_needs_dwarf_call, needs_dwarf_reg_entry_value): Rename;
	turn into methods.
	(needs_get_addr_index, needs_get_obj_addr): Remove; turn into
	methods.
	(symbol_needs_ctx_funcs): Remove.
	(dwarf2_loc_desc_get_symbol_read_needs): Update.
	* dwarf2expr.h (struct dwarf_expr_context_funcs): Remove; turn
	contents into methods.
	(struct dwarf_expr_context) <baton, funcs>: Remove.
	<read_addr_from_reg, get_reg_value, read_mem, get_frame_base,
	get_frame_cfa, get_frame_pc, get_tls_address, dwarf_call,
	impl_get_base_type, push_dwarf_block_entry_value, get_addr_index,
	get_object_address>: Declare new methods.
	(ctx_no_get_frame_base, ctx_no_get_frame_cfa)
	(ctx_no_get_frame_pc, ctx_no_get_tls_address, ctx_no_dwarf_call)
	(ctx_no_get_base_type, ctx_no_push_dwarf_reg_entry_value)
	(ctx_no_get_addr_index): Don't declare.
	* dwarf2expr.c (get_base_type): Use impl_get_base_type.
	(execute_stack_op): Update.
	(ctx_no_get_frame_base, ctx_no_get_frame_cfa)
	(ctx_no_get_frame_pc, ctx_no_get_tls_address, ctx_no_dwarf_call)
	(ctx_no_get_base_type, ctx_no_push_dwarf_reg_entry_value)
	(ctx_no_get_addr_index): Remove; now methods on
	dwarf_expr_context.
	* dwarf2-frame.c (read_addr_from_reg): Take a frame_info, not a
	baton.
	(class dwarf_expr_executor): New class.
	(get_reg_value, read_mem): Rename, turn into methods.
	(execute_stack_op): Use dwarf_expr_executor.

1 files changed, 26 insertions, 39 deletions

diff --git a/gdb/dwarf2-frame.c b/gdb/dwarf2-frame.c
index c93c362..c9962e1 100644
--- a/gdb/dwarf2-frame.c
+++ b/gdb/dwarf2-frame.c
@@ -288,33 +288,14 @@ dwarf2_frame_state_free (void *p)
 /* Helper functions for execute_stack_op.  */
 
 static CORE_ADDR
-read_addr_from_reg (void *baton, int reg)
+read_addr_from_reg (struct frame_info *this_frame, int reg)
 {
-  struct frame_info *this_frame = (struct frame_info *) baton;
   struct gdbarch *gdbarch = get_frame_arch (this_frame);
   int regnum = dwarf_reg_to_regnum_or_error (gdbarch, reg);
 
   return address_from_register (regnum, this_frame);
 }
 
-/* Implement struct dwarf_expr_context_funcs' "get_reg_value" callback.  */
-
-static struct value *
-get_reg_value (void *baton, struct type *type, int reg)
-{
-  struct frame_info *this_frame = (struct frame_info *) baton;
-  struct gdbarch *gdbarch = get_frame_arch (this_frame);
-  int regnum = dwarf_reg_to_regnum_or_error (gdbarch, reg);
-
-  return value_from_register (type, regnum, this_frame);
-}
-
-static void
-read_mem (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t len)
-{
-  read_memory (addr, buf, len);
-}
-
 /* Execute the required actions for both the DW_CFA_restore and
 DW_CFA_restore_extended instructions.  */
 static void
@@ -347,21 +328,29 @@ register %s (#%d) at %s"),
     }
 }
 
-/* Virtual method table for execute_stack_op below.  */
-
-static const struct dwarf_expr_context_funcs dwarf2_frame_ctx_funcs =
+class dwarf_expr_executor : public dwarf_expr_context
 {
-  read_addr_from_reg,
-  get_reg_value,
-  read_mem,
-  ctx_no_get_frame_base,
-  ctx_no_get_frame_cfa,
-  ctx_no_get_frame_pc,
-  ctx_no_get_tls_address,
-  ctx_no_dwarf_call,
-  ctx_no_get_base_type,
-  ctx_no_push_dwarf_reg_entry_value,
-  ctx_no_get_addr_index
+ public:
+
+  struct frame_info *this_frame;
+
+  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 gdbarch *gdbarch = get_frame_arch (this_frame);
+    int regnum = dwarf_reg_to_regnum_or_error (gdbarch, reg);
+
+    return value_from_register (type, regnum, this_frame);
+  }
+
+  void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t len) OVERRIDE
+  {
+    read_memory (addr, buf, len);
+  }
 };
 
 static CORE_ADDR
@@ -372,15 +361,14 @@ execute_stack_op (const gdb_byte *exp, ULONGEST len, int addr_size,
   CORE_ADDR result;
   struct cleanup *old_chain;
 
-  dwarf_expr_context ctx;
+  dwarf_expr_executor ctx;
   old_chain = make_cleanup_value_free_to_mark (value_mark ());
 
+  ctx.this_frame = this_frame;
   ctx.gdbarch = get_frame_arch (this_frame);
   ctx.addr_size = addr_size;
   ctx.ref_addr_size = -1;
   ctx.offset = offset;
-  ctx.baton = this_frame;
-  ctx.funcs = &dwarf2_frame_ctx_funcs;
 
   ctx.push_address (initial, initial_in_stack_memory);
   ctx.eval (exp, len);
@@ -388,8 +376,7 @@ execute_stack_op (const gdb_byte *exp, ULONGEST len, int addr_size,
   if (ctx.location == DWARF_VALUE_MEMORY)
     result = ctx.fetch_address (0);
   else if (ctx.location == DWARF_VALUE_REGISTER)
-    result = read_addr_from_reg (this_frame,
-				 value_as_long (ctx.fetch (0)));
+    result = ctx.read_addr_from_reg (value_as_long (ctx.fetch (0)));
   else
     {
       /* This is actually invalid DWARF, but if we ever do run across