[PATCH] [PR symtab/17391] gdb internal error: assertion fails in regcache.c:178
Doug Evans
dje@google.com
Tue Aug 11 01:05:00 GMT 2015
Hi.
This patch, I hope, addresses PR 17391.
I couldn't recreate 17391 but there is clearly a lack of robustness here:
gdbarch_dwarf2_reg_to_regnum can return -1 but not all callers
watch for that. Some callers do watch for it but call error themselves.
There is already dwarf2_reg_to_regnum_or_error so this patch just
changes appropriate callers of gdbarch_dwarf2_reg_to_regnum to use it.
Sometimes a register number is stored as a ULONGEST, so I changed
dwarf2_reg_to_regnum_or_error to take one.
Regression tested on amd64-linux.
2015-08-10 Doug Evans <dje@google.com>
PR symtab/17391
* dwarf2-frame.c (read_addr_from_reg): Call
dwarf2_reg_to_regnum_or_error instead of gdbarch_dwarf2_reg_to_regnum.
(get_reg_value): Ditto.
(dwarf2_fetch_cfa_info): Ditto.
(dwarf2_frame_prev_register): Ditto.
* dwarf2loc.c (dwarf_expr_read_addr_from_reg): Ditto.
(dwarf_expr_get_reg_value): Ditto.
(read_pieced_value): Ditto.
(write_pieced_value): Ditto.
(dwarf2_evaluate_loc_desc_full): Ditto.
(dwarf2_reg_to_regnum_or_error): Change to take a ULONGEST regnum.
(locexpr_regname): Improve text of bad register number.
* dwarf2loc.h (dwarf2_reg_to_regnum_or_error): Update prototype.
testsuite/
* lib/gdb.exp (_location): Add support for DW_OP_regx.
* gdb.dwarf2/bad-regnum.c: New file.
* gdb.dwarf2/bad-regnum.exp: New file.
diff --git a/gdb/dwarf2-frame.c b/gdb/dwarf2-frame.c
index 8fb2ac7..eb9f09c 100644
--- a/gdb/dwarf2-frame.c
+++ b/gdb/dwarf2-frame.c
@@ -292,7 +292,7 @@ read_addr_from_reg (void *baton, int reg)
{
struct frame_info *this_frame = (struct frame_info *) baton;
struct gdbarch *gdbarch = get_frame_arch (this_frame);
- int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg);
+ int regnum = dwarf2_reg_to_regnum_or_error (gdbarch, reg);
return address_from_register (regnum, this_frame);
}
@@ -304,7 +304,7 @@ get_reg_value (void *baton, struct type *type, int reg)
{
struct frame_info *this_frame = (struct frame_info *) baton;
struct gdbarch *gdbarch = get_frame_arch (this_frame);
- int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, reg);
+ int regnum = dwarf2_reg_to_regnum_or_error (gdbarch, reg);
return value_from_register (type, regnum, this_frame);
}
@@ -936,11 +936,7 @@ dwarf2_fetch_cfa_info (struct gdbarch *gdbarch,
CORE_ADDR pc,
{
case CFA_REG_OFFSET:
{
- int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, fs.regs.cfa_reg);
-
- if (regnum == -1)
- error (_("Unable to access DWARF register number %d"),
- (int) fs.regs.cfa_reg); /* FIXME */
+ int regnum = dwarf2_reg_to_regnum_or_error (gdbarch, fs.regs.cfa_reg);
*regnum_out = regnum;
if (fs.armcc_cfa_offsets_reversed)
@@ -1324,8 +1320,8 @@ dwarf2_frame_prev_register (struct frame_info
*this_frame, void **this_cache,
return frame_unwind_got_memory (this_frame, regnum, addr);
case DWARF2_FRAME_REG_SAVED_REG:
- realnum
- = gdbarch_dwarf2_reg_to_regnum (gdbarch, cache->reg[regnum].loc.reg);
+ realnum = dwarf2_reg_to_regnum_or_error
+ (gdbarch, cache->reg[regnum].loc.reg);
return frame_unwind_got_register (this_frame, regnum, realnum);
case DWARF2_FRAME_REG_SAVED_EXP:
@@ -1368,7 +1364,7 @@ dwarf2_frame_prev_register (struct frame_info
*this_frame, void **this_cache,
case DWARF2_FRAME_REG_RA_OFFSET:
addr = cache->reg[regnum].loc.offset;
- regnum = gdbarch_dwarf2_reg_to_regnum
+ regnum = dwarf2_reg_to_regnum_or_error
(gdbarch, cache->retaddr_reg.loc.reg);
addr += get_frame_register_unsigned (this_frame, regnum);
return frame_unwind_got_address (this_frame, regnum, addr);
diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c
index d8e432e..b8f172d 100644
--- a/gdb/dwarf2loc.c
+++ b/gdb/dwarf2loc.c
@@ -312,7 +312,7 @@ dwarf_expr_read_addr_from_reg (void *baton, int
dwarf_regnum)
{
struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
struct gdbarch *gdbarch = get_frame_arch (debaton->frame);
- int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, dwarf_regnum);
+ int regnum = dwarf2_reg_to_regnum_or_error (gdbarch, dwarf_regnum);
return address_from_register (regnum, debaton->frame);
}
@@ -324,7 +324,7 @@ dwarf_expr_get_reg_value (void *baton, struct type
*type, int dwarf_regnum)
{
struct dwarf_expr_baton *debaton = (struct dwarf_expr_baton *) baton;
struct gdbarch *gdbarch = get_frame_arch (debaton->frame);
- int regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, dwarf_regnum);
+ int regnum = dwarf2_reg_to_regnum_or_error (gdbarch, dwarf_regnum);
return value_from_register (type, regnum, debaton->frame);
}
@@ -1682,40 +1682,31 @@ read_pieced_value (struct value *v)
case DWARF_VALUE_REGISTER:
{
struct gdbarch *arch = get_frame_arch (frame);
- int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, p->v.regno);
+ int gdb_regnum = dwarf2_reg_to_regnum_or_error (arch, p->v.regno);
+ int optim, unavail;
+ int reg_offset = source_offset;
- if (gdb_regnum != -1)
+ if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
+ && this_size < register_size (arch, gdb_regnum))
{
- int optim, unavail;
- int reg_offset = source_offset;
-
- if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
- && this_size < register_size (arch, gdb_regnum))
- {
- /* Big-endian, and we want less than full size. */
- reg_offset = register_size (arch, gdb_regnum) - this_size;
- /* We want the lower-order THIS_SIZE_BITS of the bytes
- we extract from the register. */
- source_offset_bits += 8 * this_size - this_size_bits;
- }
-
- if (!get_frame_register_bytes (frame, gdb_regnum, reg_offset,
- this_size, buffer,
- &optim, &unavail))
- {
- /* Just so garbage doesn't ever shine through. */
- memset (buffer, 0, this_size);
-
- if (optim)
- mark_value_bits_optimized_out (v, offset, this_size_bits);
- if (unavail)
- mark_value_bits_unavailable (v, offset, this_size_bits);
- }
+ /* Big-endian, and we want less than full size. */
+ reg_offset = register_size (arch, gdb_regnum) - this_size;
+ /* We want the lower-order THIS_SIZE_BITS of the bytes
+ we extract from the register. */
+ source_offset_bits += 8 * this_size - this_size_bits;
}
- else
+
+ if (!get_frame_register_bytes (frame, gdb_regnum, reg_offset,
+ this_size, buffer,
+ &optim, &unavail))
{
- error (_("Unable to access DWARF register number %s"),
- paddress (arch, p->v.regno));
+ /* Just so garbage doesn't ever shine through. */
+ memset (buffer, 0, this_size);
+
+ if (optim)
+ mark_value_bits_optimized_out (v, offset, this_size_bits);
+ if (unavail)
+ mark_value_bits_unavailable (v, offset, this_size_bits);
}
}
break;
@@ -1874,52 +1865,43 @@ write_pieced_value (struct value *to, struct value
*from)
case DWARF_VALUE_REGISTER:
{
struct gdbarch *arch = get_frame_arch (frame);
- int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, p->v.regno);
+ int gdb_regnum = dwarf2_reg_to_regnum_or_error (arch, p->v.regno);
+ int reg_offset = dest_offset;
- if (gdb_regnum != -1)
+ if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
+ && this_size <= register_size (arch, gdb_regnum))
{
- int reg_offset = dest_offset;
+ /* Big-endian, and we want less than full size. */
+ reg_offset = register_size (arch, gdb_regnum) - this_size;
+ }
- if (gdbarch_byte_order (arch) == BFD_ENDIAN_BIG
- && this_size <= register_size (arch, gdb_regnum))
- {
- /* Big-endian, and we want less than full size. */
- reg_offset = register_size (arch, gdb_regnum) - this_size;
- }
+ if (need_bitwise)
+ {
+ int optim, unavail;
- if (need_bitwise)
+ if (!get_frame_register_bytes (frame, gdb_regnum, reg_offset,
+ this_size, buffer,
+ &optim, &unavail))
{
- int optim, unavail;
-
- if (!get_frame_register_bytes (frame, gdb_regnum, reg_offset,
- this_size, buffer,
- &optim, &unavail))
- {
- if (optim)
- throw_error (OPTIMIZED_OUT_ERROR,
- _("Can't do read-modify-write to "
- "update bitfield; containing word "
- "has been optimized out"));
- if (unavail)
- throw_error (NOT_AVAILABLE_ERROR,
- _("Can't do read-modify-write to update "
- "bitfield; containing word "
- "is unavailable"));
- }
- copy_bitwise (buffer, dest_offset_bits,
- contents, source_offset_bits,
- this_size_bits,
- bits_big_endian);
+ if (optim)
+ throw_error (OPTIMIZED_OUT_ERROR,
+ _("Can't do read-modify-write to "
+ "update bitfield; containing word "
+ "has been optimized out"));
+ if (unavail)
+ throw_error (NOT_AVAILABLE_ERROR,
+ _("Can't do read-modify-write to update "
+ "bitfield; containing word "
+ "is unavailable"));
}
-
- put_frame_register_bytes (frame, gdb_regnum, reg_offset,
- this_size, source_buffer);
- }
- else
- {
- error (_("Unable to write to DWARF register number %s"),
- paddress (arch, p->v.regno));
+ copy_bitwise (buffer, dest_offset_bits,
+ contents, source_offset_bits,
+ this_size_bits,
+ bits_big_endian);
}
+
+ put_frame_register_bytes (frame, gdb_regnum, reg_offset,
+ this_size, source_buffer);
}
break;
case DWARF_VALUE_MEMORY:
@@ -2260,30 +2242,28 @@ dwarf2_evaluate_loc_desc_full (struct type *type,
struct frame_info *frame,
struct gdbarch *arch = get_frame_arch (frame);
int dwarf_regnum
= longest_to_int (value_as_long (dwarf_expr_fetch (ctx, 0)));
- int gdb_regnum = gdbarch_dwarf2_reg_to_regnum (arch, dwarf_regnum);
+ int gdb_regnum = dwarf2_reg_to_regnum_or_error
+ (arch, dwarf_regnum);
if (byte_offset != 0)
error (_("cannot use offset on synthetic pointer to register"));
do_cleanups (value_chain);
- if (gdb_regnum == -1)
- error (_("Unable to access DWARF register number %d"),
- dwarf_regnum);
- retval = value_from_register (type, gdb_regnum, frame);
- if (value_optimized_out (retval))
- {
- struct value *tmp;
-
- /* This means the register has undefined value / was
- not saved. As we're computing the location of some
- variable etc. in the program, not a value for
- inspecting a register ($pc, $sp, etc.), return a
- generic optimized out value instead, so that we show
- <optimized out> instead of <not saved>. */
- do_cleanups (value_chain);
- tmp = allocate_value (type);
- value_contents_copy (tmp, 0, retval, 0, TYPE_LENGTH (type));
- retval = tmp;
- }
+ retval = value_from_register (type, gdb_regnum, frame);
+ if (value_optimized_out (retval))
+ {
+ struct value *tmp;
+
+ /* This means the register has undefined value / was
+ not saved. As we're computing the location of some
+ variable etc. in the program, not a value for
+ inspecting a register ($pc, $sp, etc.), return a
+ generic optimized out value instead, so that we show
+ <optimized out> instead of <not saved>. */
+ do_cleanups (value_chain);
+ tmp = allocate_value (type);
+ value_contents_copy (tmp, 0, retval, 0, TYPE_LENGTH (type));
+ retval = tmp;
+ }
}
break;
@@ -2777,11 +2757,17 @@ unimplemented (unsigned int op)
/* See dwarf2loc.h. */
int
-dwarf2_reg_to_regnum_or_error (struct gdbarch *arch, int dwarf_reg)
+dwarf2_reg_to_regnum_or_error (struct gdbarch *arch, ULONGEST dwarf_reg)
{
- int reg = gdbarch_dwarf2_reg_to_regnum (arch, dwarf_reg);
+ int reg;
+
+ if (dwarf_reg > INT_MAX)
+ error (_("Unable to access DWARF register number %s"),
+ pulongest (dwarf_reg));
+ reg = gdbarch_dwarf2_reg_to_regnum (arch, (int) dwarf_reg);
if (reg == -1)
- error (_("Unable to access DWARF register number %d"), dwarf_reg);
+ error (_("Unable to access DWARF register number %s"),
+ pulongest (dwarf_reg));
return reg;
}
@@ -3572,7 +3558,17 @@ locexpr_regname (struct gdbarch *gdbarch, int
dwarf_regnum)
{
int regnum;
+ /* This doesn't use gdbarch_dwarf2_reg_to_regnum_or_error on purpose.
+ We'd rather print *something* here than throw an error. */
regnum = gdbarch_dwarf2_reg_to_regnum (gdbarch, dwarf_regnum);
+ /* gdbarch_register_name may just return "", return something more
+ descriptive for bad register numbers. */
+ if (regnum == -1)
+ {
+ /* The text is output as "$bad_register_number".
+ That is why we use the underscores. */
+ return _("bad_register_number");
+ }
return gdbarch_register_name (gdbarch, regnum);
}
diff --git a/gdb/dwarf2loc.h b/gdb/dwarf2loc.h
index f3630ac..41916eb 100644
--- a/gdb/dwarf2loc.h
+++ b/gdb/dwarf2loc.h
@@ -287,8 +287,12 @@ extern struct call_site_chain *call_site_find_chain
(struct gdbarch *gdbarch,
ARCH is the architecture.
DWARF_REG is the register.
This will throw an exception if the DWARF register cannot be
- translated to an architecture register. */
+ translated to an architecture register.
+ This takes a ULONGEST instead of an int because some callers actually
have
+ a ULONGEST. Negative values passed as ints will still be flagged as
+ invalid. */
-extern int dwarf2_reg_to_regnum_or_error (struct gdbarch *arch, int
dwarf_reg);
+extern int dwarf2_reg_to_regnum_or_error (struct gdbarch *arch,
+ ULONGEST dwarf_reg);
#endif /* dwarf2loc.h */
diff --git a/gdb/testsuite/gdb.dwarf2/bad-regnum.c
b/gdb/testsuite/gdb.dwarf2/bad-regnum.c
new file mode 100644
index 0000000..35230f2
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/bad-regnum.c
@@ -0,0 +1,22 @@
+/* Copyright 2015 Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+
+int
+main ()
+{
+ return 0;
+}
diff --git a/gdb/testsuite/gdb.dwarf2/bad-regnum.exp
b/gdb/testsuite/gdb.dwarf2/bad-regnum.exp
new file mode 100644
index 0000000..7356adb
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/bad-regnum.exp
@@ -0,0 +1,64 @@
+# Copyright 2015 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+load_lib dwarf.exp
+
+# This test can only be run on targets which support DWARF-2 and use gas.
+if {![dwarf2_support]} {
+ return 0
+}
+
+standard_testfile bad-regnum.c bad-regnum-dw.S
+
+# Make some DWARF for the test.
+set asm_file [standard_output_file $srcfile2]
+Dwarf::assemble $asm_file {
+ cu {} {
+ DW_TAG_compile_unit {
+ {DW_AT_language @DW_LANG_C}
+ {DW_AT_name bad-regnum-dw.c}
+ {DW_AT_comp_dir /tmp}
+ } {
+ declare_labels integer_label
+
+ integer_label: DW_TAG_base_type {
+ {DW_AT_byte_size 4 DW_FORM_sdata}
+ {DW_AT_encoding @DW_ATE_signed}
+ {DW_AT_name integer}
+ }
+
+ DW_TAG_variable {
+ {DW_AT_name foo}
+ {DW_AT_type :$integer_label}
+ {DW_AT_location {
+ DW_OP_regx 2147483647
+ } SPECIAL_expr}
+ {external 1 flag}
+ }
+ }
+ }
+}
+
+if { [prepare_for_testing ${testfile}.exp ${testfile} \
+ [list $srcfile $asm_file] {nodebug}] } {
+ return -1
+}
+
+if ![runto_main] {
+ return -1
+}
+
+gdb_test "info addr foo" \
+ "Symbol \"foo\" is warning: Unmapped DWARF Register #2147483647
encountered.\[\r\n\]+a variable in \\\$bad_register_number."
diff --git a/gdb/testsuite/lib/dwarf.exp b/gdb/testsuite/lib/dwarf.exp
index 515334e..df7a36d 100644
--- a/gdb/testsuite/lib/dwarf.exp
+++ b/gdb/testsuite/lib/dwarf.exp
@@ -836,6 +836,10 @@ namespace eval Dwarf {
_op .${_cu_addr_size}byte [lindex $line 1]
}
+ DW_OP_regx {
+ _op .uleb128 [lindex $line 1]
+ }
+
DW_OP_pick -
DW_OP_const1u -
DW_OP_const1s {
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