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[patch, rfc, v2] MIPS dwarf2 location lists
- From: "Ulrich Weigand" <uweigand at de dot ibm dot com>
- To: gdb-patches at sourceware dot org
- Cc: dan at codesourcery dot com (Daniel Jacobowitz), brobecker at adacore dot com (Joel Brobecker)
- Date: Fri, 11 Jun 2010 15:47:56 +0200 (CEST)
- Subject: [patch, rfc, v2] MIPS dwarf2 location lists
Joel Brobecker wrote:
> > > * dwarf2expr.c (dwarf2_read_address): Make static.
> > > * dwarf2expr.h (dwarf2_read_address): Remove prototype.
> > > * dwarf2loc.c (find_location_expression): Add relocation offset
> > > to base-address-selection entry base addresses. Read addresses
> > > (and offsets) as signed/unsigned integers, depending on the
> > > BFD's sign_extend_vma flag. Do not call dwarf2_read_address.
> > > (locexpr_describe_location): Read TLS offset as unsigned
> > > integer. Do not call dwarf2_read_address.
> >
> > Ping. Any thoughts on whether we should go with this?
>
> Can't really say much about the patch itself; but FWIW, I tested it
> on mips-irix, and saw no regression.
Thanks for running the test! And sorry for taking so long to get back
to this patch ... Dan agreed (in an off-line mail) that the patch
makes sense to him, so I'm planning to go forward with it.
Due to Tom's recent dwarf2 changes, a couple of modifications were
required. An updated patch is appended below.
Retested with no regressions on i386-linux.
I'm planning on committing the patch next week.
Thanks,
Ulrich
ChangeLog:
* dwarf2expr.c (dwarf2_read_address): Make static.
* dwarf2expr.h (dwarf2_read_address): Remove prototype.
* dwarf2loc.c (find_location_expression): Add relocation offset
to base-address-selection entry base addresses. Read addresses
(and offsets) as signed/unsigned integers, depending on the
BFD's sign_extend_vma flag. Do not call dwarf2_read_address.
(loclist_describe_location): Likewise.
(disassemble_dwarf_expression): Read DW_OP_addr operand as
unsigned integer. Do not call dwarf2_read_address.
(locexpr_describe_location): Likewise for DW_OP_GNU_push_tls_address.
Index: gdb/dwarf2expr.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2expr.c,v
retrieving revision 1.46
diff -u -p -r1.46 dwarf2expr.c
--- gdb/dwarf2expr.c 7 Jun 2010 19:55:33 -0000 1.46
+++ gdb/dwarf2expr.c 11 Jun 2010 13:19:13 -0000
@@ -263,7 +263,7 @@ read_sleb128 (const gdb_byte *buf, const
/* Read an address of size ADDR_SIZE from BUF, and verify that it
doesn't extend past BUF_END. */
-CORE_ADDR
+static CORE_ADDR
dwarf2_read_address (struct gdbarch *gdbarch, const gdb_byte *buf,
const gdb_byte *buf_end, int addr_size)
{
Index: gdb/dwarf2expr.h
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2expr.h,v
retrieving revision 1.25
diff -u -p -r1.25 dwarf2expr.h
--- gdb/dwarf2expr.h 7 Jun 2010 19:55:33 -0000 1.25
+++ gdb/dwarf2expr.h 11 Jun 2010 13:19:13 -0000
@@ -204,8 +204,6 @@ const gdb_byte *read_uleb128 (const gdb_
ULONGEST * r);
const gdb_byte *read_sleb128 (const gdb_byte *buf, const gdb_byte *buf_end,
LONGEST * r);
-CORE_ADDR dwarf2_read_address (struct gdbarch *gdbarch, const gdb_byte *buf,
- const gdb_byte *buf_end, int addr_size);
const char *dwarf_stack_op_name (unsigned int, int);
Index: gdb/dwarf2loc.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2loc.c,v
retrieving revision 1.88
diff -u -p -r1.88 dwarf2loc.c
--- gdb/dwarf2loc.c 7 Jun 2010 19:55:33 -0000 1.88
+++ gdb/dwarf2loc.c 11 Jun 2010 13:19:13 -0000
@@ -67,6 +67,7 @@ find_location_expression (struct dwarf2_
struct gdbarch *gdbarch = get_objfile_arch (objfile);
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
unsigned int addr_size = dwarf2_per_cu_addr_size (baton->per_cu);
+ int signed_addr_p = bfd_get_sign_extend_vma (objfile->obfd);
CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1));
/* Adjust base_address for relocatable objects. */
CORE_ADDR base_offset = ANOFFSET (objfile->section_offsets,
@@ -81,21 +82,25 @@ find_location_expression (struct dwarf2_
if (buf_end - loc_ptr < 2 * addr_size)
error (_("find_location_expression: Corrupted DWARF expression."));
- low = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
+ if (signed_addr_p)
+ low = extract_signed_integer (loc_ptr, addr_size, byte_order);
+ else
+ low = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
+ loc_ptr += addr_size;
+
+ if (signed_addr_p)
+ high = extract_signed_integer (loc_ptr, addr_size, byte_order);
+ else
+ high = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
loc_ptr += addr_size;
/* A base-address-selection entry. */
- if (low == base_mask)
+ if ((low & base_mask) == base_mask)
{
- base_address = dwarf2_read_address (gdbarch,
- loc_ptr, buf_end, addr_size);
- loc_ptr += addr_size;
+ base_address = high + base_offset;
continue;
}
- high = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
- loc_ptr += addr_size;
-
/* An end-of-list entry. */
if (low == 0 && high == 0)
return NULL;
@@ -1468,15 +1473,14 @@ locexpr_describe_location_piece (struct
&& data[1 + addr_size] == DW_OP_GNU_push_tls_address
&& piece_end_p (data + 2 + addr_size, end))
{
- CORE_ADDR offset = dwarf2_read_address (gdbarch,
- data + 1,
- end,
- addr_size);
+ ULONGEST offset;
+ offset = extract_unsigned_integer (data + 1, addr_size,
+ gdbarch_byte_order (gdbarch));
fprintf_filtered (stream,
- _("a thread-local variable at offset %s "
+ _("a thread-local variable at offset 0x%s "
"in the thread-local storage for `%s'"),
- paddress (gdbarch, offset), objfile->name);
+ phex_nz (offset, addr_size), objfile->name);
data += 1 + addr_size + 1;
}
@@ -1513,7 +1517,6 @@ disassemble_dwarf_expression (struct ui_
|| (data[0] != DW_OP_piece && data[0] != DW_OP_bit_piece)))
{
enum dwarf_location_atom op = *data++;
- CORE_ADDR addr;
ULONGEST ul;
LONGEST l;
const char *name;
@@ -1528,9 +1531,10 @@ disassemble_dwarf_expression (struct ui_
switch (op)
{
case DW_OP_addr:
- addr = dwarf2_read_address (arch, data, end, addr_size);
+ ul = extract_unsigned_integer (data, addr_size,
+ gdbarch_byte_order (arch));
data += addr_size;
- fprintf_filtered (stream, " %s", paddress (arch, addr));
+ fprintf_filtered (stream, " 0x%s", phex_nz (ul, addr_size));
break;
case DW_OP_const1u:
@@ -1938,6 +1942,7 @@ loclist_describe_location (struct symbol
enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
unsigned int addr_size = dwarf2_per_cu_addr_size (dlbaton->per_cu);
int offset_size = dwarf2_per_cu_offset_size (dlbaton->per_cu);
+ int signed_addr_p = bfd_get_sign_extend_vma (objfile->obfd);
CORE_ADDR base_mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1));
/* Adjust base_address for relocatable objects. */
CORE_ADDR base_offset = ANOFFSET (objfile->section_offsets,
@@ -1956,23 +1961,27 @@ loclist_describe_location (struct symbol
error (_("Corrupted DWARF expression for symbol \"%s\"."),
SYMBOL_PRINT_NAME (symbol));
- low = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
+ if (signed_addr_p)
+ low = extract_signed_integer (loc_ptr, addr_size, byte_order);
+ else
+ low = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
+ loc_ptr += addr_size;
+
+ if (signed_addr_p)
+ high = extract_signed_integer (loc_ptr, addr_size, byte_order);
+ else
+ high = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
loc_ptr += addr_size;
/* A base-address-selection entry. */
- if (low == base_mask)
+ if ((low & base_mask) == base_mask)
{
- base_address = dwarf2_read_address (gdbarch,
- loc_ptr, buf_end, addr_size);
+ base_address = high + base_offset;
fprintf_filtered (stream, _(" Base address %s"),
paddress (gdbarch, base_address));
- loc_ptr += addr_size;
continue;
}
- high = extract_unsigned_integer (loc_ptr, addr_size, byte_order);
- loc_ptr += addr_size;
-
/* An end-of-list entry. */
if (low == 0 && high == 0)
break;
--
Dr. Ulrich Weigand
GNU Toolchain for Linux on System z and Cell BE
Ulrich.Weigand@de.ibm.com