[PATCH v3 12/28] Add indirect_implicit_ptr to dwarf_location class
Zoran Zaric
zoran.zaric@amd.com
Thu Oct 14 09:32:19 GMT 2021
From: Zoran Zaric <Zoran.Zaric@amd.com>
Similarly to the is_implicit_ptr_at method, the existing function
callback interface of the computed struct value, requiers a way to
apply indirection to an implicit pointer on a given offset of a given
length of an underlying location description.
This is different then reading from a struct value object (previously
described write_to_gdb_value method) in a way that the result of this
operation is expected to be a struct value of a pointed source level
variable instead of reading the value of that variable.
In the same way this is also different operation then the deref method
because the deref returns a read value of a given type from that
location description.
gdb/ChangeLog:
* dwarf2/expr.c (dwarf_location::indirect_implicit_ptr):
New method.
(dwarf_implicit_pointer::indirect_implicit_ptr): New method.
(dwarf_composite::indirect_implicit_ptr): New method.
---
gdb/dwarf2/expr.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 73 insertions(+)
diff --git a/gdb/dwarf2/expr.c b/gdb/dwarf2/expr.c
index aa36a992e09..af84710b054 100644
--- a/gdb/dwarf2/expr.c
+++ b/gdb/dwarf2/expr.c
@@ -474,6 +474,24 @@ class dwarf_location : public dwarf_entry
return false;
}
+ /* Recursive indirecting of the implicit pointer location description
+ if that location is or encapsulates an implicit pointer. The
+ operation is performed in a given FRAME context, using the TYPE as
+ the type of the pointer. Where POINTER_OFFSET is an offset
+ applied to that implicit pointer location description before the
+ operation. BIT_OFFSET is a bit offset applied to the location and
+ BIT_LENGTH is a bit length of the read.
+
+ Indirecting is only performed on the implicit pointer location
+ description parts of the location. */
+ virtual value *indirect_implicit_ptr (frame_info *frame, struct type *type,
+ LONGEST pointer_offset = 0,
+ LONGEST bit_offset = 0,
+ int bit_length = 0) const
+ {
+ return nullptr;
+ }
+
protected:
/* Architecture of the location. */
gdbarch *m_arch;
@@ -1103,6 +1121,11 @@ class dwarf_implicit_pointer final : public dwarf_location
return true;
}
+ value *indirect_implicit_ptr (frame_info *frame, struct type *type,
+ LONGEST pointer_offset = 0,
+ LONGEST bit_offset = 0,
+ int bit_length = 0) const override;
+
private:
/* Per object file data of the implicit pointer. */
dwarf2_per_objfile *m_per_objfile;
@@ -1155,6 +1178,17 @@ dwarf_implicit_pointer::read (frame_info *frame, gdb_byte *buf,
}
}
+value *
+dwarf_implicit_pointer::indirect_implicit_ptr (frame_info *frame,
+ struct type *type,
+ LONGEST pointer_offset,
+ LONGEST bit_offset,
+ int bit_length) const
+{
+ return indirect_synthetic_pointer (m_die_offset, m_offset + pointer_offset,
+ m_per_cu, m_per_objfile, frame, type);
+}
+
/* Composite location description entry. */
class dwarf_composite final : public dwarf_location
@@ -1191,6 +1225,11 @@ class dwarf_composite final : public dwarf_location
bool is_implicit_ptr_at (LONGEST bit_offset, int bit_length) const override;
+ value *indirect_implicit_ptr (frame_info *frame, struct type *type,
+ LONGEST pointer_offset = 0,
+ LONGEST bit_offset = 0,
+ int bit_length = 0) const override;
+
private:
/* Composite piece that contains a piece location
description and it's size. */
@@ -1424,6 +1463,40 @@ dwarf_composite::is_implicit_ptr_at (LONGEST bit_offset, int bit_length) const
return false;
}
+value *
+dwarf_composite::indirect_implicit_ptr (frame_info *frame, struct type *type,
+ LONGEST pointer_offset,
+ LONGEST bit_offset,
+ int bit_length) const
+{
+ LONGEST total_bit_offset = HOST_CHAR_BIT * m_offset
+ + m_bit_suboffset + bit_offset;
+
+ /* Advance to the first non-skipped piece. */
+ for (const piece &piece : m_pieces)
+ {
+ ULONGEST read_bit_length = piece.size;
+
+ if (total_bit_offset >= read_bit_length)
+ {
+ total_bit_offset -= read_bit_length;
+ continue;
+ }
+
+ read_bit_length -= total_bit_offset;
+
+ if (bit_length < read_bit_length)
+ read_bit_length = bit_length;
+
+ return piece.location->indirect_implicit_ptr (frame, type,
+ pointer_offset,
+ total_bit_offset,
+ read_bit_length);
+ }
+
+ return nullptr;
+}
+
struct piece_closure
{
/* Reference count. */
--
2.17.1
More information about the Gdb-patches
mailing list