Move read_mem to dwarf_expr_context

Following the idea of merging the evaluators, the read_mem method can
be moved from dwarf_expr_executor and dwarf_evaluate_loc_desc classes
to their base class dwarf_expr_context.

gdb/ChangeLog:

	* dwarf2/expr.c (dwarf_expr_context::read_mem): Move from
	dwarf_evaluate_loc_desc.
	* dwarf2/frame.c (dwarf_expr_executor::read_mem): Remove
	method.
	* dwarf2/loc.c (dwarf_evaluate_loc_desc::read_mem): Move to
	dwarf_expr_context.

Change-Id: Ied28c2c0fc808fb5e41f9816df8ac731fa4ac2fa

gdb/dwarf2/expr.c

@@ -263,6 +263,15 @@ dwarf_expr_context::dwarf_call (cu_offset die_cu_off)
   this->eval (block.data, block.size);
 }
 
+/* See expr.h.  */
+
+void
+dwarf_expr_context::read_mem (gdb_byte *buf, CORE_ADDR addr,
+			      size_t length)
+{
+  read_memory (addr, buf, length);
+}
+
 /* Require that TYPE be an integral type; throw an exception if not.  */
 
 static void

gdb/dwarf2/expr.h

@@ -196,7 +196,7 @@ struct dwarf_expr_context
   CORE_ADDR obj_address;
 
   /* Read LENGTH bytes at ADDR into BUF.  */
-  virtual void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t length) = 0;
+  virtual void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t length);
 
   /* Push on DWARF stack an entry evaluated for DW_TAG_call_site's
      parameter matching KIND and KIND_U at the caller of specified BATON.

gdb/dwarf2/frame.c

@@ -231,11 +231,6 @@ public:
     : dwarf_expr_context (per_objfile)
   {}
 
-  void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t len) override
-  {
-    read_memory (addr, buf, len);
-  }
-
   void push_dwarf_reg_entry_value (enum call_site_parameter_kind kind,
 				   union call_site_parameter_u kind_u,
 				   int deref_size) override

gdb/dwarf2/loc.c

@@ -686,13 +686,6 @@ public:
 
     this->eval (data_src, size);
   }
-
-  /* Read memory at ADDR (length LEN) into BUF.  */
-
-  void read_mem (gdb_byte *buf, CORE_ADDR addr, size_t len) override
-  {
-    read_memory (addr, buf, len);
-  }
 };
 
 /* See dwarf2loc.h.  */