Move compilation unit info to dwarf_expr_context

This patch moves the compilation unit context information and support
from dwarf_expr_executor and dwarf_evaluate_loc_desc to
dwarf_expr_context evaluator. The idea is to report an error when a
given operation requires a compilation unit information to be resolved,
which is not available.

With this change, it also makes sense to always acquire ref_addr_size
information from the compilation unit context, considering that all
DWARF operations that refer to that information require a compilation
unit context to be present during their evaluation.

gdb/ChangeLog:

	* dwarf2/expr.c (ensure_have_per_cu): New function.
	(dwarf_expr_context::dwarf_expr_context): Add compilation unit
	context information.
	(dwarf_expr_context::get_base_type): Move from
	dwarf_evaluate_loc_desc.
	(dwarf_expr_context::get_addr_index): Remove method.
	(dwarf_expr_context::dwarf_variable_value): Remove method.
	(dwarf_expr_context::execute_stack_op): Call compilation unit
	context info check. Inline get_addr_index and
	dwarf_variable_value methods.
	* dwarf2/expr.h (struct dwarf_expr_context): Add compilation
	context info.
        (dwarf_expr_context::get_addr_index): Remove method.
        (dwarf_expr_context::dwarf_variable_value): Remove method.
        (dwarf_expr_context::ref_addr_size): Remove member.
	* dwarf2/frame.c (dwarf_expr_executor::get_addr_index): Remove
	method.
	(dwarf_expr_executor::dwarf_variable_value): Remove method.
	* dwarf2/loc.c (sect_variable_value): Expose function.
	(dwarf_evaluate_loc_desc::get_addr_index): Remove method.
	(dwarf_evaluate_loc_desc::dwarf_variable_value): Remove method.
	(class dwarf_evaluate_loc_desc): Move compilation unit context
	information to dwarf_expr_context class.
	* dwarf2/loc.h (sect_variable_value): Expose function.

1 files changed, 3 insertions, 34 deletions

diff --git a/gdb/dwarf2/loc.c b/gdb/dwarf2/loc.c
index 723d9a4..7e565d3 100644
--- a/gdb/dwarf2/loc.c
+++ b/gdb/dwarf2/loc.c
@@ -651,12 +651,10 @@ compute_var_value (const char *name)
   return nullptr;
 }
 
-/* Given context CTX, section offset SECT_OFF, and compilation unit
-   data PER_CU, execute the "variable value" operation on the DIE
-   found at SECT_OFF.  */
+/* See loc.h.  */
 
-static struct value *
-sect_variable_value (struct dwarf_expr_context *ctx, sect_offset sect_off,
+struct value *
+sect_variable_value (sect_offset sect_off,
 		     dwarf2_per_cu_data *per_cu,
 		     dwarf2_per_objfile *per_objfile)
 {
@@ -696,7 +694,6 @@ public:
     : dwarf_expr_context (per_objfile)
   {}
 
-  struct dwarf2_per_cu_data *per_cu;
   CORE_ADDR obj_address;
 
   /* Helper function for dwarf2_evaluate_loc_desc.  Computes the PC for
@@ -722,32 +719,6 @@ public:
     per_cu_dwarf_call (this, die_offset, per_cu, per_objfile);
   }
 
-  /* Helper interface of sect_variable_value for
-     dwarf2_evaluate_loc_desc.  */
-
-  struct value *dwarf_variable_value (sect_offset sect_off) override
-  {
-    return sect_variable_value (this, sect_off, per_cu, per_objfile);
-  }
-
-  struct type *get_base_type (cu_offset die_offset, int size) override
-  {
-    struct type *result = dwarf2_get_die_type (die_offset, per_cu, per_objfile);
-    if (result == NULL)
-      error (_("Could not find type for DW_OP_const_type"));
-    if (size != 0 && TYPE_LENGTH (result) != size)
-      error (_("DW_OP_const_type has different sizes for type and data"));
-    return result;
-  }
-
-  /* Callback function for dwarf2_evaluate_loc_desc.
-     Fetch the address indexed by DW_OP_addrx or DW_OP_GNU_addr_index.  */
-
-  CORE_ADDR get_addr_index (unsigned int index) override
-  {
-    return dwarf2_read_addr_index (per_cu, per_objfile, index);
-  }
-
   /* Callback function for get_object_address. Return the address of the VLA
      object.  */
 
@@ -2237,7 +2208,6 @@ dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame,
 
   ctx.gdbarch = per_objfile->objfile->arch ();
   ctx.addr_size = per_cu->addr_size ();
-  ctx.ref_addr_size = per_cu->ref_addr_size ();
 
   try
     {
@@ -2504,7 +2474,6 @@ dwarf2_locexpr_baton_eval (const struct dwarf2_locexpr_baton *dlbaton,
 
   ctx.gdbarch = per_objfile->objfile->arch ();
   ctx.addr_size = dlbaton->per_cu->addr_size ();
-  ctx.ref_addr_size = dlbaton->per_cu->ref_addr_size ();
 
   if (push_initial_value)
     ctx.push_address (ctx.obj_address, false);