From: Zoran Zaric <Zoran.Zaric@amd.com>
To: gdb-patches@sourceware.org
Subject: [PATCH 18/43] Add new register access interface to expr.c
Date: Mon, 1 Mar 2021 14:45:55 +0000 [thread overview]
Message-ID: <20210301144620.103016-19-Zoran.Zaric@amd.com> (raw)
In-Reply-To: <20210301144620.103016-1-Zoran.Zaric@amd.com>
DWARF expression evaluator is currently using get_frame_register_bytes
and put_frame_register_bytes interface for register access.
The problem with evaluator using this interface is that it allows a
bleed out register access. This means that if the caller specifies a
larger amount of data then the size of a specified register, the
operation will continue accessing the neighboring registers until a
full amount of data has been reached.
DWARF specification does not define this behavior, so a new simplified
register access interface is needed instead.
* dwarf2/expr.c (read_from_register): New function.
(write_to_register): New function.
(rw_pieced_value): Now calls the read_from_register and
write_to_register functions.
---
gdb/dwarf2/expr.c | 128 ++++++++++++++++++++++++++++++++++++++--------
1 file changed, 106 insertions(+), 22 deletions(-)
diff --git a/gdb/dwarf2/expr.c b/gdb/dwarf2/expr.c
index c50bb3c8d90..5a1fd5b941f 100644
--- a/gdb/dwarf2/expr.c
+++ b/gdb/dwarf2/expr.c
@@ -106,6 +106,96 @@ read_addr_from_reg (struct frame_info *frame, int reg)
return address_from_register (regnum, frame);
}
+/* Read register REGNUM's contents in a given FRAME context.
+
+ The data read is offsetted by OFFSET, and the number of bytes read
+ is defined by LENGTH. The data is then copied into the
+ caller-managed buffer BUF.
+
+ If the register is optimized out or unavailable for the given
+ FRAME, the OPTIMIZED and UNAVAILABLE outputs are set
+ accordingly */
+
+static void
+read_from_register (struct frame_info *frame, int regnum,
+ CORE_ADDR offset, gdb::array_view<gdb_byte> buf,
+ int *optimized, int *unavailable)
+{
+ struct gdbarch *gdbarch = get_frame_arch (frame);
+ int regsize = register_size (gdbarch, regnum);
+ int numregs = gdbarch_num_cooked_regs (gdbarch);
+ int length = buf.size ();
+
+ /* If a register is wholly inside the OFFSET, skip it. */
+ if (frame == NULL || !regsize
+ || offset + length > regsize || numregs < regnum)
+ {
+ *optimized = 0;
+ *unavailable = 1;
+ return;
+ }
+
+ gdb::byte_vector temp_buf (regsize);
+ enum lval_type lval;
+ CORE_ADDR address;
+ int realnum;
+
+ frame_register (frame, regnum, optimized, unavailable,
+ &lval, &address, &realnum, temp_buf.data ());
+
+ if (!*optimized && !*unavailable)
+ memcpy (buf.data (), (char *) temp_buf.data () + offset, length);
+
+ return;
+}
+
+/* Write register REGNUM's contents in a given FRAME context.
+
+ The data written is offsetted by OFFSET, and the number of bytes
+ written is defined by LENGTH. The data is copied from
+ caller-managed buffer BUF.
+
+ If the register is optimized out or unavailable for the given
+ FRAME, the OPTIMIZED and UNAVAILABLE outputs are set
+ accordingly. */
+
+static void
+write_to_register (struct frame_info *frame, int regnum,
+ CORE_ADDR offset, gdb::array_view<gdb_byte> buf,
+ int *optimized, int *unavailable)
+{
+ struct gdbarch *gdbarch = get_frame_arch (frame);
+ int regsize = register_size (gdbarch, regnum);
+ int numregs = gdbarch_num_cooked_regs (gdbarch);
+ int length = buf.size ();
+
+ /* If a register is wholly inside of OFFSET, skip it. */
+ if (frame == NULL || !regsize
+ || offset + length > regsize || numregs < regnum)
+ {
+ *optimized = 0;
+ *unavailable = 1;
+ return;
+ }
+
+ gdb::byte_vector temp_buf (regsize);
+ enum lval_type lval;
+ CORE_ADDR address;
+ int realnum;
+
+ frame_register (frame, regnum, optimized, unavailable,
+ &lval, &address, &realnum, temp_buf.data ());
+
+ if (!*optimized && !*unavailable)
+ {
+ memcpy ((char *) temp_buf.data () + offset, buf.data (), length);
+
+ put_frame_register (frame, regnum, temp_buf.data ());
+ }
+
+ return;
+}
+
struct piece_closure
{
/* Reference count. */
@@ -243,22 +333,18 @@ rw_pieced_value (struct value *v, struct value *from)
if (from == NULL)
{
/* Read mode. */
- if (!get_frame_register_bytes (frame, gdb_regnum,
- bits_to_skip / 8,
- buffer, &optim, &unavail))
- {
- if (optim)
- mark_value_bits_optimized_out (v, offset,
- this_size_bits);
- if (unavail)
- mark_value_bits_unavailable (v, offset,
- this_size_bits);
- break;
- }
-
- copy_bitwise (v_contents, offset,
- buffer.data (), bits_to_skip % 8,
- this_size_bits, bits_big_endian);
+ read_from_register (frame, gdb_regnum, bits_to_skip / 8,
+ buffer, &optim, &unavail);
+
+ if (optim)
+ mark_value_bits_optimized_out (v, offset, this_size_bits);
+ if (unavail)
+ mark_value_bits_unavailable (v, offset, this_size_bits);
+ /* Only copy data if valid. */
+ if (!optim && !unavail)
+ copy_bitwise (v_contents, offset,
+ buffer.data (), bits_to_skip % 8,
+ this_size_bits, bits_big_endian);
}
else
{
@@ -267,9 +353,8 @@ rw_pieced_value (struct value *v, struct value *from)
{
/* Data is copied non-byte-aligned into the register.
Need some bits from original register value. */
- get_frame_register_bytes (frame, gdb_regnum,
- bits_to_skip / 8,
- buffer, &optim, &unavail);
+ read_from_register (frame, gdb_regnum, bits_to_skip / 8,
+ buffer, &optim, &unavail);
if (optim)
throw_error (OPTIMIZED_OUT_ERROR,
_("Can't do read-modify-write to "
@@ -285,9 +370,8 @@ rw_pieced_value (struct value *v, struct value *from)
copy_bitwise (buffer.data (), bits_to_skip % 8,
from_contents, offset,
this_size_bits, bits_big_endian);
- put_frame_register_bytes (frame, gdb_regnum,
- bits_to_skip / 8,
- buffer);
+ write_to_register (frame, gdb_regnum, bits_to_skip / 8,
+ buffer, &optim, &unavail);
}
}
break;
--
2.17.1
next prev parent reply other threads:[~2021-03-01 14:47 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-01 14:45 [PATCH 00/43 V2] Allow location description on the DWARF stack Zoran Zaric
2021-03-01 14:45 ` [PATCH 01/43] Replace the symbol needs evaluator with a parser Zoran Zaric
2021-04-27 1:20 ` Simon Marchi
2021-04-28 10:17 ` Zoran Zaric
2021-04-28 14:08 ` Simon Marchi
2021-04-28 15:02 ` Zoran Zaric
2021-04-28 15:31 ` Zoran Zaric
2021-03-01 14:45 ` [PATCH 02/43] Cleanup of the dwarf_expr_context constructor Zoran Zaric
2021-04-27 1:23 ` Simon Marchi
2021-04-28 10:19 ` Zoran Zaric
2021-03-01 14:45 ` [PATCH 03/43] Move frame context info to dwarf_expr_context Zoran Zaric
2021-04-27 2:19 ` Simon Marchi
2021-04-28 10:51 ` Zoran Zaric
2021-04-28 14:14 ` Simon Marchi
2021-04-28 15:55 ` Zoran Zaric
2021-03-01 14:45 ` [PATCH 04/43] Remove get_frame_cfa from dwarf_expr_context Zoran Zaric
2021-03-01 14:45 ` [PATCH 05/43] Move compilation unit info to dwarf_expr_context Zoran Zaric
2021-04-27 2:58 ` Simon Marchi
2021-04-28 11:28 ` Zoran Zaric
2021-03-01 14:45 ` [PATCH 06/43] Move dwarf_call " Zoran Zaric
2021-03-01 14:45 ` [PATCH 07/43] Move get_object_address " Zoran Zaric
2021-04-27 3:12 ` Simon Marchi
2021-04-28 11:34 ` Zoran Zaric
2021-03-01 14:45 ` [PATCH 08/43] Move read_mem " Zoran Zaric
2021-03-01 14:45 ` [PATCH 09/43] Move push_dwarf_reg_entry_value to expr.c Zoran Zaric
2021-04-27 3:56 ` Simon Marchi
2021-04-28 11:36 ` Zoran Zaric
2021-03-01 14:45 ` [PATCH 10/43] Inline get_reg_value method of dwarf_expr_context Zoran Zaric
2021-03-01 14:45 ` [PATCH 11/43] Remove empty frame and full evaluators Zoran Zaric
2021-03-01 14:45 ` [PATCH 12/43] Merge evaluate_for_locexpr_baton evaluator Zoran Zaric
2021-04-28 1:33 ` Simon Marchi
2021-04-28 11:39 ` Zoran Zaric
2021-03-01 14:45 ` [PATCH 13/43] Move piece_closure and its support to expr.c Zoran Zaric
2021-04-28 1:56 ` Simon Marchi
2021-04-28 11:40 ` Zoran Zaric
2021-03-01 14:45 ` [PATCH 14/43] Make value_copy also copy the stack data member Zoran Zaric
2021-04-28 2:01 ` Simon Marchi
2021-04-28 11:43 ` Zoran Zaric
2021-03-01 14:45 ` [PATCH 15/43] Make DWARF evaluator return a single struct value Zoran Zaric
2021-04-28 2:21 ` Simon Marchi
2021-04-28 11:47 ` Zoran Zaric
2021-04-28 14:24 ` Simon Marchi
2021-03-01 14:45 ` [PATCH 16/43] Simplify dwarf_expr_context class interface Zoran Zaric
2021-04-28 2:45 ` Simon Marchi
2021-04-28 13:15 ` Zoran Zaric
2021-04-28 14:41 ` Simon Marchi
2021-04-28 15:39 ` Zoran Zaric
2021-04-28 19:19 ` Simon Marchi
2021-04-29 15:49 ` Simon Marchi
2021-04-29 15:55 ` Zoran Zaric
2021-03-01 14:45 ` [PATCH 17/43] Add as_lval argument to expression evaluator Zoran Zaric
2021-04-28 3:04 ` Simon Marchi
2021-04-28 13:16 ` Zoran Zaric
2021-04-28 3:30 ` Simon Marchi
2021-03-01 14:45 ` Zoran Zaric [this message]
2021-03-08 23:52 ` [PATCH 18/43] Add new register access interface to expr.c Lancelot SIX
2021-04-28 3:25 ` Simon Marchi
2021-04-28 13:29 ` Zoran Zaric
2021-04-28 14:48 ` Simon Marchi
2021-04-28 15:42 ` Zoran Zaric
2021-03-01 14:45 ` [PATCH 19/43] Add new memory " Zoran Zaric
2021-04-30 21:24 ` Simon Marchi
2021-03-01 14:45 ` [PATCH 20/43] Add new classes that model DWARF stack element Zoran Zaric
2021-03-01 14:45 ` [PATCH 21/43] Add to_location method to DWARF entry classes Zoran Zaric
2021-03-01 14:45 ` [PATCH 22/43] Add to_value " Zoran Zaric
2021-03-01 14:46 ` [PATCH 23/43] Add read method to location description classes Zoran Zaric
2021-03-01 14:46 ` [PATCH 24/43] Add write " Zoran Zaric
2021-03-01 14:46 ` [PATCH 25/43] Add deref " Zoran Zaric
2021-03-01 14:46 ` [PATCH 26/43] Add read_from_gdb_value method to dwarf_location Zoran Zaric
2021-03-01 14:46 ` [PATCH 27/43] Add write_to_gdb_value " Zoran Zaric
2021-03-01 14:46 ` [PATCH 28/43] Add is_implicit_ptr_at " Zoran Zaric
2021-03-01 14:46 ` [PATCH 29/43] Add indirect_implicit_ptr to dwarf_location class Zoran Zaric
2021-03-01 14:46 ` [PATCH 30/43] Add new computed struct value callback interface Zoran Zaric
2021-03-01 14:46 ` [PATCH 31/43] Add to_gdb_value method to DWARF entry class Zoran Zaric
2021-03-01 14:46 ` [PATCH 32/43] Change DWARF stack to use new dwarf_entry classes Zoran Zaric
2021-03-01 14:46 ` [PATCH 33/43] Remove old computed struct value callbacks Zoran Zaric
2021-03-01 14:46 ` [PATCH 34/43] Comments cleanup between expr.h and expr.c Zoran Zaric
2021-03-01 14:46 ` [PATCH 35/43] Remove dwarf_expr_context from expr.h interface Zoran Zaric
2021-03-01 14:46 ` [PATCH 36/43] Move read_addr_from_reg function to frame.c Zoran Zaric
2021-03-01 14:46 ` [PATCH 37/43] Add frame info check to DW_OP_reg operations Zoran Zaric
2021-03-01 14:46 ` [PATCH 38/43] Remove DWARF expression composition check Zoran Zaric
2021-03-01 14:46 ` [PATCH 39/43] Change back the symbol needs to use the evaluator Zoran Zaric
2021-03-01 14:46 ` [PATCH 40/43] Add support for any location description in CFI Zoran Zaric
2021-03-01 14:46 ` [PATCH 41/43] Add DWARF operations for byte and bit offset Zoran Zaric
2021-03-01 14:46 ` [PATCH 42/43] Add support for DW_OP_LLVM_undefined operation Zoran Zaric
2021-03-01 14:46 ` [PATCH 43/43] Add support for nested composite locations Zoran Zaric
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