[PATCH 01/23] dwarf: add dwarf3 DW_OP_push_object_address opcode

Keven Boell
2014-06-04T05:54:37Z

The opcode pushes the address of the object being evaluated. The semantic is
equivalent to the implicit push of the base address of a data member location.

2014-05-28 Sanimir Agovic <sanimir.agovic@intel.com>
Keven Boell <keven.boell@intel.com>

* dwarf2expr.c (execute_stack_op) <DW_OP_push_object_address>: New case.
* dwarf2expr.h (struct dwarf_expr_context_funcs)
<DW_OP_push_object_address>: New function pointer get_object_addr.
* dwarf2loc.c (struct dwarf_expr_baton): Add obj_address.
(dwarf_expr_get_obj_addr): New function.
(struct dwarf_expr_context_funcs): Add
dwarf_expr_get_obj_addr to dwarf_expr_ctx_funcs.
(dwarf2_evaluate_loc_desc_full): Initialize baton.obj_address.
(dwarf2_locexpr_baton_eval): Set baton.obj_address to addr.
(needs_get_obj_addr): New function.
(struct dwarf_expr_context_funcs): Add needs_get_obj_addr to
needs_frame_ctx_funcs.

Change-Id: Ied9e1ba632e8d35d0ec00cc832b96d432449fd82

Signed-off-by: Keven Boell <keven.boell@intel.com>
---
gdb/dwarf2expr.c | 6 ++++++
gdb/dwarf2expr.h | 4 ----
gdb/dwarf2loc.c | 41 +++++++++++++++++++++++++++++++++++++----
gdb/dwarf2loc.h | 1 +
gdb/gdbtypes.c | 16 ++++++++--------
5 files changed, 52 insertions(+), 16 deletions(-)

diff --git a/gdb/dwarf2expr.c b/gdb/dwarf2expr.c
index 36c9f66..274ba62 100644
--- a/gdb/dwarf2expr.c
+++ b/gdb/dwarf2expr.c
@@ -1478,6 +1478,12 @@ execute_stack_op (struct dwarf_expr_context *ctx,
}
break;

+ case DW_OP_push_object_address:
+ /* Return the address of the object we are currently observing. */
+ result = (ctx->funcs->get_object_address) (ctx->baton);
+ result_val = value_from_ulongest (address_type, result);
+ break;
+
default:
error (_("Unhandled dwarf expression opcode 0x%x"), op);
}
diff --git a/gdb/dwarf2expr.h b/gdb/dwarf2expr.h
index 39dadf3..8cebbe8 100644
--- a/gdb/dwarf2expr.h
+++ b/gdb/dwarf2expr.h
@@ -84,12 +84,8 @@ struct dwarf_expr_context_funcs
This can throw an exception if the index is out of range. */
CORE_ADDR (*get_addr_index) (void *baton, unsigned int index);

-#if 0
- /* Not yet implemented. */
-
/* Return the `object address' for DW_OP_push_object_address. */
CORE_ADDR (*get_object_address) (void *baton);
-#endif
};

/* The location of a value. */
diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c
index 5517442..5402f66 100644
--- a/gdb/dwarf2loc.c
+++ b/gdb/dwarf2loc.c
@@ -306,6 +306,7 @@ struct dwarf_expr_baton
{
struct frame_info *frame;
struct dwarf2_per_cu_data *per_cu;
+ CORE_ADDR obj_address;
};

/* Helper functions for dwarf2_evaluate_loc_desc. */
@@ -1209,6 +1210,7 @@ dwarf_expr_push_dwarf_reg_entry_value (struct dwarf_expr_context *ctx,

baton_local.frame = caller_frame;
baton_local.per_cu = caller_per_cu;
+ baton_local.obj_address = 0;

saved_ctx.gdbarch = ctx->gdbarch;
saved_ctx.addr_size = ctx->addr_size;
@@ -1238,6 +1240,22 @@ dwarf_expr_get_addr_index (void *baton, unsigned int index)
return dwarf2_read_addr_index (debaton->per_cu, index);
}

+/* Callback function for get_object_address. Return the address of the VLA
+ object. */
+
+static CORE_ADDR
+dwarf_expr_get_obj_addr (void *baton)
+{
+ struct dwarf_expr_baton *debaton = baton;
+
+ gdb_assert (debaton != NULL);
+
+ if (debaton->obj_address == 0)
+ error (_("Location address is not set."));
+
+ return debaton->obj_address;
+}
+
/* VALUE must be of type lval_computed with entry_data_value_funcs. Perform
the indirect method on it, that is use its stored target value, the sole
purpose of entry_data_value_funcs.. */
@@ -2202,7 +2220,8 @@ static const struct dwarf_expr_context_funcs dwarf_expr_ctx_funcs =
dwarf_expr_dwarf_call,
dwarf_expr_get_base_type,
dwarf_expr_push_dwarf_reg_entry_value,
- dwarf_expr_get_addr_index
+ dwarf_expr_get_addr_index,
+ dwarf_expr_get_obj_addr
};

/* Evaluate a location description, starting at DATA and with length
@@ -2231,6 +2250,7 @@ dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame,

baton.frame = frame;
baton.per_cu = per_cu;
+ baton.obj_address = 0;

ctx = new_dwarf_expr_context ();
old_chain = make_cleanup_free_dwarf_expr_context (ctx);
@@ -2436,6 +2456,7 @@ dwarf2_evaluate_loc_desc (struct type *type, struct frame_info *frame,

static int
dwarf2_locexpr_baton_eval (const struct dwarf2_locexpr_baton *dlbaton,
+ CORE_ADDR addr,
CORE_ADDR *valp)
{
struct dwarf_expr_context *ctx;
@@ -2451,6 +2472,7 @@ dwarf2_locexpr_baton_eval (const struct dwarf2_locexpr_baton *dlbaton,

baton.frame = get_selected_frame (NULL);
baton.per_cu = dlbaton->per_cu;
+ baton.obj_address = addr;

objfile = dwarf2_per_cu_objfile (dlbaton->per_cu);

@@ -2491,7 +2513,8 @@ dwarf2_locexpr_baton_eval (const struct dwarf2_locexpr_baton *dlbaton,
/* See dwarf2loc.h. */

int
-dwarf2_evaluate_property (const struct dynamic_prop *prop, CORE_ADDR *value)
+dwarf2_evaluate_property (const struct dynamic_prop *prop, CORE_ADDR address,
+ CORE_ADDR *value)
{
if (prop == NULL)
return 0;
@@ -2502,7 +2525,7 @@ dwarf2_evaluate_property (const struct dynamic_prop *prop, CORE_ADDR *value)
{
const struct dwarf2_property_baton *baton = prop->data.baton;

- if (dwarf2_locexpr_baton_eval (&baton->locexpr, value))
+ if (dwarf2_locexpr_baton_eval (&baton->locexpr, address, value))
{
if (baton->referenced_type)
{
@@ -2653,6 +2676,15 @@ needs_get_addr_index (void *baton, unsigned int index)
return 1;
}

+/* DW_OP_push_object_address has a frame already passed thru. */
+
+static CORE_ADDR
+needs_get_obj_addr (void *baton)
+{
+ /* Nothing to do. */
+ return 1;
+}
+
/* Virtual method table for dwarf2_loc_desc_needs_frame below. */

static const struct dwarf_expr_context_funcs needs_frame_ctx_funcs =
@@ -2667,7 +2699,8 @@ static const struct dwarf_expr_context_funcs needs_frame_ctx_funcs =
needs_frame_dwarf_call,
NULL, /* get_base_type */
needs_dwarf_reg_entry_value,
- needs_get_addr_index
+ needs_get_addr_index,
+ needs_get_obj_addr
};

/* Return non-zero iff the location expression at DATA (length SIZE)
diff --git a/gdb/dwarf2loc.h b/gdb/dwarf2loc.h
index 8ad5fa9..04e2792 100644
--- a/gdb/dwarf2loc.h
+++ b/gdb/dwarf2loc.h
@@ -96,6 +96,7 @@ struct value *dwarf2_evaluate_loc_desc (struct type *type,
into VALUE, otherwise returns 0. */

int dwarf2_evaluate_property (const struct dynamic_prop *prop,
+ CORE_ADDR address,
CORE_ADDR *value);

CORE_ADDR dwarf2_read_addr_index (struct dwarf2_per_cu_data *per_cu,
diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
index d58193e..2a0cfe4 100644
--- a/gdb/gdbtypes.c
+++ b/gdb/gdbtypes.c
@@ -1646,7 +1646,7 @@ is_dynamic_type (struct type *type)
}

static struct type *
-resolve_dynamic_range (struct type *dyn_range_type)
+resolve_dynamic_range (struct type *dyn_range_type, CORE_ADDR addr)
{
CORE_ADDR value;
struct type *static_range_type;
@@ -1657,7 +1657,7 @@ resolve_dynamic_range (struct type *dyn_range_type)
gdb_assert (TYPE_CODE (dyn_range_type) == TYPE_CODE_RANGE);

prop = &TYPE_RANGE_DATA (dyn_range_type)->low;
- if (dwarf2_evaluate_property (prop, &value))
+ if (dwarf2_evaluate_property (prop, addr, &value))
{
low_bound.kind = PROP_CONST;
low_bound.data.const_val = value;
@@ -1669,7 +1669,7 @@ resolve_dynamic_range (struct type *dyn_range_type)
}

prop = &TYPE_RANGE_DATA (dyn_range_type)->high;
- if (dwarf2_evaluate_property (prop, &value))
+ if (dwarf2_evaluate_property (prop, addr, &value))
{
high_bound.kind = PROP_CONST;
high_bound.data.const_val = value;
@@ -1696,7 +1696,7 @@ resolve_dynamic_range (struct type *dyn_range_type)
of the associated array. */

static struct type *
-resolve_dynamic_array (struct type *type)
+resolve_dynamic_array (struct type *type, CORE_ADDR addr)
{
CORE_ADDR value;
struct type *elt_type;
@@ -1707,12 +1707,12 @@ resolve_dynamic_array (struct type *type)

elt_type = type;
range_type = check_typedef (TYPE_INDEX_TYPE (elt_type));
- range_type = resolve_dynamic_range (range_type);
+ range_type = resolve_dynamic_range (range_type, addr);

ary_dim = check_typedef (TYPE_TARGET_TYPE (elt_type));

if (ary_dim != NULL && TYPE_CODE (ary_dim) == TYPE_CODE_ARRAY)
- elt_type = resolve_dynamic_array (TYPE_TARGET_TYPE (type));
+ elt_type = resolve_dynamic_array (TYPE_TARGET_TYPE (type), addr);
else
elt_type = TYPE_TARGET_TYPE (type);

@@ -1751,11 +1751,11 @@ resolve_dynamic_type (struct type *type, CORE_ADDR addr)
}

case TYPE_CODE_ARRAY:
- resolved_type = resolve_dynamic_array (type);
+ resolved_type = resolve_dynamic_array (type, addr);
break;

case TYPE_CODE_RANGE:
- resolved_type = resolve_dynamic_range (type);
+ resolved_type = resolve_dynamic_range (type, addr);
break;
}

--
1.7.9.5