This is the mail archive of the
gdb-patches@sourceware.org
mailing list for the GDB project.
[pushed] Split value_fetch_lazy
- From: Simon Marchi <simon dot marchi at polymtl dot ca>
- To: gdb-patches at sourceware dot org
- Cc: Simon Marchi <simon dot marchi at ericsson dot com>
- Date: Sat, 2 Jun 2018 09:31:24 -0400
- Subject: [pushed] Split value_fetch_lazy
From: Simon Marchi <simon.marchi@ericsson.com>
While reading value_fetch_lazy, I thought it would be good to split it
in small functions (especially the part that handles lval_register).
gdb/ChangeLog:
* value.c (value_fetch_lazy_bitfield): New.
(value_fetch_lazy_memory): New.
(value_fetch_lazy_register): New.
(value_fetch_lazy): Factor out to smaller functions.
---
gdb/ChangeLog | 7 ++
gdb/value.c | 303 +++++++++++++++++++++++++++-----------------------
2 files changed, 169 insertions(+), 141 deletions(-)
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f1eed4e72991..9895d2fcc3dc 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,10 @@
+2018-06-02 Simon Marchi <simon.marchi@ericsson.com>
+
+ * value.c (value_fetch_lazy_bitfield): New.
+ (value_fetch_lazy_memory): New.
+ (value_fetch_lazy_register): New.
+ (value_fetch_lazy): Factor out to smaller functions.
+
2018-06-01 Tom Tromey <tom@tromey.com>
* cp-name-parser.y (backslashable, represented): Now const.
diff --git a/gdb/value.c b/gdb/value.c
index 6bb6b8eb61eb..146ce8e94db3 100644
--- a/gdb/value.c
+++ b/gdb/value.c
@@ -3714,6 +3714,165 @@ value_initialized (const struct value *val)
return val->initialized;
}
+/* Helper for value_fetch_lazy when the value is a bitfield. */
+
+static void
+value_fetch_lazy_bitfield (struct value *val)
+{
+ gdb_assert (value_bitsize (val) != 0);
+
+ /* To read a lazy bitfield, read the entire enclosing value. This
+ prevents reading the same block of (possibly volatile) memory once
+ per bitfield. It would be even better to read only the containing
+ word, but we have no way to record that just specific bits of a
+ value have been fetched. */
+ struct type *type = check_typedef (value_type (val));
+ struct value *parent = value_parent (val);
+
+ if (value_lazy (parent))
+ value_fetch_lazy (parent);
+
+ unpack_value_bitfield (val, value_bitpos (val), value_bitsize (val),
+ value_contents_for_printing (parent),
+ value_offset (val), parent);
+}
+
+/* Helper for value_fetch_lazy when the value is in memory. */
+
+static void
+value_fetch_lazy_memory (struct value *val)
+{
+ gdb_assert (VALUE_LVAL (val) == lval_memory);
+
+ CORE_ADDR addr = value_address (val);
+ struct type *type = check_typedef (value_enclosing_type (val));
+
+ if (TYPE_LENGTH (type))
+ read_value_memory (val, 0, value_stack (val),
+ addr, value_contents_all_raw (val),
+ type_length_units (type));
+}
+
+/* Helper for value_fetch_lazy when the value is in a register. */
+
+static void
+value_fetch_lazy_register (struct value *val)
+{
+ struct frame_info *next_frame;
+ int regnum;
+ struct type *type = check_typedef (value_type (val));
+ struct value *new_val = val, *mark = value_mark ();
+
+ /* Offsets are not supported here; lazy register values must
+ refer to the entire register. */
+ gdb_assert (value_offset (val) == 0);
+
+ while (VALUE_LVAL (new_val) == lval_register && value_lazy (new_val))
+ {
+ struct frame_id next_frame_id = VALUE_NEXT_FRAME_ID (new_val);
+
+ next_frame = frame_find_by_id (next_frame_id);
+ regnum = VALUE_REGNUM (new_val);
+
+ gdb_assert (next_frame != NULL);
+
+ /* Convertible register routines are used for multi-register
+ values and for interpretation in different types
+ (e.g. float or int from a double register). Lazy
+ register values should have the register's natural type,
+ so they do not apply. */
+ gdb_assert (!gdbarch_convert_register_p (get_frame_arch (next_frame),
+ regnum, type));
+
+ /* FRAME was obtained, above, via VALUE_NEXT_FRAME_ID.
+ Since a "->next" operation was performed when setting
+ this field, we do not need to perform a "next" operation
+ again when unwinding the register. That's why
+ frame_unwind_register_value() is called here instead of
+ get_frame_register_value(). */
+ new_val = frame_unwind_register_value (next_frame, regnum);
+
+ /* If we get another lazy lval_register value, it means the
+ register is found by reading it from NEXT_FRAME's next frame.
+ frame_unwind_register_value should never return a value with
+ the frame id pointing to NEXT_FRAME. If it does, it means we
+ either have two consecutive frames with the same frame id
+ in the frame chain, or some code is trying to unwind
+ behind get_prev_frame's back (e.g., a frame unwind
+ sniffer trying to unwind), bypassing its validations. In
+ any case, it should always be an internal error to end up
+ in this situation. */
+ if (VALUE_LVAL (new_val) == lval_register
+ && value_lazy (new_val)
+ && frame_id_eq (VALUE_NEXT_FRAME_ID (new_val), next_frame_id))
+ internal_error (__FILE__, __LINE__,
+ _("infinite loop while fetching a register"));
+ }
+
+ /* If it's still lazy (for instance, a saved register on the
+ stack), fetch it. */
+ if (value_lazy (new_val))
+ value_fetch_lazy (new_val);
+
+ /* Copy the contents and the unavailability/optimized-out
+ meta-data from NEW_VAL to VAL. */
+ set_value_lazy (val, 0);
+ value_contents_copy (val, value_embedded_offset (val),
+ new_val, value_embedded_offset (new_val),
+ type_length_units (type));
+
+ if (frame_debug)
+ {
+ struct gdbarch *gdbarch;
+ struct frame_info *frame;
+ /* VALUE_FRAME_ID is used here, instead of VALUE_NEXT_FRAME_ID,
+ so that the frame level will be shown correctly. */
+ frame = frame_find_by_id (VALUE_FRAME_ID (val));
+ regnum = VALUE_REGNUM (val);
+ gdbarch = get_frame_arch (frame);
+
+ fprintf_unfiltered (gdb_stdlog,
+ "{ value_fetch_lazy "
+ "(frame=%d,regnum=%d(%s),...) ",
+ frame_relative_level (frame), regnum,
+ user_reg_map_regnum_to_name (gdbarch, regnum));
+
+ fprintf_unfiltered (gdb_stdlog, "->");
+ if (value_optimized_out (new_val))
+ {
+ fprintf_unfiltered (gdb_stdlog, " ");
+ val_print_optimized_out (new_val, gdb_stdlog);
+ }
+ else
+ {
+ int i;
+ const gdb_byte *buf = value_contents (new_val);
+
+ if (VALUE_LVAL (new_val) == lval_register)
+ fprintf_unfiltered (gdb_stdlog, " register=%d",
+ VALUE_REGNUM (new_val));
+ else if (VALUE_LVAL (new_val) == lval_memory)
+ fprintf_unfiltered (gdb_stdlog, " address=%s",
+ paddress (gdbarch,
+ value_address (new_val)));
+ else
+ fprintf_unfiltered (gdb_stdlog, " computed");
+
+ fprintf_unfiltered (gdb_stdlog, " bytes=");
+ fprintf_unfiltered (gdb_stdlog, "[");
+ for (i = 0; i < register_size (gdbarch, regnum); i++)
+ fprintf_unfiltered (gdb_stdlog, "%02x", buf[i]);
+ fprintf_unfiltered (gdb_stdlog, "]");
+ }
+
+ fprintf_unfiltered (gdb_stdlog, " }\n");
+ }
+
+ /* Dispose of the intermediate values. This prevents
+ watchpoints from trying to watch the saved frame pointer. */
+ value_free_to_mark (mark);
+}
+
/* Load the actual content of a lazy value. Fetch the data from the
user's process and clear the lazy flag to indicate that the data in
the buffer is valid.
@@ -3733,149 +3892,11 @@ value_fetch_lazy (struct value *val)
gdb_assert (val->optimized_out.empty ());
gdb_assert (val->unavailable.empty ());
if (value_bitsize (val))
- {
- /* To read a lazy bitfield, read the entire enclosing value. This
- prevents reading the same block of (possibly volatile) memory once
- per bitfield. It would be even better to read only the containing
- word, but we have no way to record that just specific bits of a
- value have been fetched. */
- struct type *type = check_typedef (value_type (val));
- struct value *parent = value_parent (val);
-
- if (value_lazy (parent))
- value_fetch_lazy (parent);
-
- unpack_value_bitfield (val,
- value_bitpos (val), value_bitsize (val),
- value_contents_for_printing (parent),
- value_offset (val), parent);
- }
+ value_fetch_lazy_bitfield (val);
else if (VALUE_LVAL (val) == lval_memory)
- {
- CORE_ADDR addr = value_address (val);
- struct type *type = check_typedef (value_enclosing_type (val));
-
- if (TYPE_LENGTH (type))
- read_value_memory (val, 0, value_stack (val),
- addr, value_contents_all_raw (val),
- type_length_units (type));
- }
+ value_fetch_lazy_memory (val);
else if (VALUE_LVAL (val) == lval_register)
- {
- struct frame_info *next_frame;
- int regnum;
- struct type *type = check_typedef (value_type (val));
- struct value *new_val = val, *mark = value_mark ();
-
- /* Offsets are not supported here; lazy register values must
- refer to the entire register. */
- gdb_assert (value_offset (val) == 0);
-
- while (VALUE_LVAL (new_val) == lval_register && value_lazy (new_val))
- {
- struct frame_id next_frame_id = VALUE_NEXT_FRAME_ID (new_val);
-
- next_frame = frame_find_by_id (next_frame_id);
- regnum = VALUE_REGNUM (new_val);
-
- gdb_assert (next_frame != NULL);
-
- /* Convertible register routines are used for multi-register
- values and for interpretation in different types
- (e.g. float or int from a double register). Lazy
- register values should have the register's natural type,
- so they do not apply. */
- gdb_assert (!gdbarch_convert_register_p (get_frame_arch (next_frame),
- regnum, type));
-
- /* FRAME was obtained, above, via VALUE_NEXT_FRAME_ID.
- Since a "->next" operation was performed when setting
- this field, we do not need to perform a "next" operation
- again when unwinding the register. That's why
- frame_unwind_register_value() is called here instead of
- get_frame_register_value(). */
- new_val = frame_unwind_register_value (next_frame, regnum);
-
- /* If we get another lazy lval_register value, it means the
- register is found by reading it from NEXT_FRAME's next frame.
- frame_unwind_register_value should never return a value with
- the frame id pointing to NEXT_FRAME. If it does, it means we
- either have two consecutive frames with the same frame id
- in the frame chain, or some code is trying to unwind
- behind get_prev_frame's back (e.g., a frame unwind
- sniffer trying to unwind), bypassing its validations. In
- any case, it should always be an internal error to end up
- in this situation. */
- if (VALUE_LVAL (new_val) == lval_register
- && value_lazy (new_val)
- && frame_id_eq (VALUE_NEXT_FRAME_ID (new_val), next_frame_id))
- internal_error (__FILE__, __LINE__,
- _("infinite loop while fetching a register"));
- }
-
- /* If it's still lazy (for instance, a saved register on the
- stack), fetch it. */
- if (value_lazy (new_val))
- value_fetch_lazy (new_val);
-
- /* Copy the contents and the unavailability/optimized-out
- meta-data from NEW_VAL to VAL. */
- set_value_lazy (val, 0);
- value_contents_copy (val, value_embedded_offset (val),
- new_val, value_embedded_offset (new_val),
- type_length_units (type));
-
- if (frame_debug)
- {
- struct gdbarch *gdbarch;
- struct frame_info *frame;
- /* VALUE_FRAME_ID is used here, instead of VALUE_NEXT_FRAME_ID,
- so that the frame level will be shown correctly. */
- frame = frame_find_by_id (VALUE_FRAME_ID (val));
- regnum = VALUE_REGNUM (val);
- gdbarch = get_frame_arch (frame);
-
- fprintf_unfiltered (gdb_stdlog,
- "{ value_fetch_lazy "
- "(frame=%d,regnum=%d(%s),...) ",
- frame_relative_level (frame), regnum,
- user_reg_map_regnum_to_name (gdbarch, regnum));
-
- fprintf_unfiltered (gdb_stdlog, "->");
- if (value_optimized_out (new_val))
- {
- fprintf_unfiltered (gdb_stdlog, " ");
- val_print_optimized_out (new_val, gdb_stdlog);
- }
- else
- {
- int i;
- const gdb_byte *buf = value_contents (new_val);
-
- if (VALUE_LVAL (new_val) == lval_register)
- fprintf_unfiltered (gdb_stdlog, " register=%d",
- VALUE_REGNUM (new_val));
- else if (VALUE_LVAL (new_val) == lval_memory)
- fprintf_unfiltered (gdb_stdlog, " address=%s",
- paddress (gdbarch,
- value_address (new_val)));
- else
- fprintf_unfiltered (gdb_stdlog, " computed");
-
- fprintf_unfiltered (gdb_stdlog, " bytes=");
- fprintf_unfiltered (gdb_stdlog, "[");
- for (i = 0; i < register_size (gdbarch, regnum); i++)
- fprintf_unfiltered (gdb_stdlog, "%02x", buf[i]);
- fprintf_unfiltered (gdb_stdlog, "]");
- }
-
- fprintf_unfiltered (gdb_stdlog, " }\n");
- }
-
- /* Dispose of the intermediate values. This prevents
- watchpoints from trying to watch the saved frame pointer. */
- value_free_to_mark (mark);
- }
+ value_fetch_lazy_register (val);
else if (VALUE_LVAL (val) == lval_computed
&& value_computed_funcs (val)->read != NULL)
value_computed_funcs (val)->read (val);
--
2.17.1