diff options
Diffstat (limited to 'gdb')
| -rw-r--r-- | gdb/testsuite/gdb.base/value-history-unavailable.c | 29 | ||||
| -rw-r--r-- | gdb/testsuite/gdb.base/value-history-unavailable.exp | 73 | ||||
| -rw-r--r-- | gdb/valarith.c | 15 | ||||
| -rw-r--r-- | gdb/value.c | 17 |
4 files changed, 133 insertions, 1 deletions
diff --git a/gdb/testsuite/gdb.base/value-history-unavailable.c b/gdb/testsuite/gdb.base/value-history-unavailable.c new file mode 100644 index 0000000..b0c2f0a --- /dev/null +++ b/gdb/testsuite/gdb.base/value-history-unavailable.c @@ -0,0 +1,29 @@ +/* This testcase is part of GDB, the GNU debugger. + + Copyright (C) 2023 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/>. */ + +struct +{ + unsigned char x[1024]; + unsigned char a[1024]; + unsigned char y[1024]; +} a = { {-1} }; + +int +main () +{ + return 0; +} diff --git a/gdb/testsuite/gdb.base/value-history-unavailable.exp b/gdb/testsuite/gdb.base/value-history-unavailable.exp new file mode 100644 index 0000000..8949be0 --- /dev/null +++ b/gdb/testsuite/gdb.base/value-history-unavailable.exp @@ -0,0 +1,73 @@ +# Copyright (C) 2023 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/>. + +# Test GDB's value availability ranges. + +standard_testfile + +if { [prepare_for_testing "failed to prepare" $testfile $srcfile] } { + return -1 +} + +if ![runto_main] then { + perror "couldn't run to breakpoint" + continue +} + +set target_char_mask [get_valueof "/u" "a.x\[0]" "255" "get target char mask"] +set target_char_bit 0 +for {set i $target_char_mask} {$i > 0} {set i [expr $i >> 1]} { + incr target_char_bit +} +set target_char_rank -1 +for {set i $target_char_bit} {$i > 0} {set i [expr $i >> 1]} { + incr target_char_rank +} + +# Verify accesses to original inferior data. +gdb_test "print a.a" "\\\$2 = '\\\\000' <repeats 1023 times>" +gdb_test "print a.a\[-1\]" "\\\$3 = 0 '\\\\000'" +gdb_test "print a.a\[1024\]" "\\\$4 = 0 '\\\\000'" + +# Verify in-range value history accesses. +gdb_test "print \$2" "\\\$5 = '\\\\000' <repeats 1023 times>" +gdb_test "print \$2\[0\]" "\\\$6 = 0 '\\\\000'" +gdb_test "print \$2\[1023\]" "\\\$7 = 0 '\\\\000'" + +# Values outside the array recorded will have not been retrieved. +gdb_test "print \$2\[-1\]" "\\\$8 = <unavailable>" +gdb_test "print \$2\[1024\]" "\\\$9 = <unavailable>" +gdb_test "print \$2\[-1LL << 63 - $target_char_rank\]" \ + "\\\$10 = <unavailable>" +gdb_test "print \$2\[(1LL << 63 - $target_char_rank) - 1\]" \ + "\\\$11 = <unavailable>" + +# Accesses through pointers in history go straight to the inferior though. +gdb_test "print \$2\[0\]@1" "\\\$12 = \"\"" +gdb_test "print \$2\[-1\]@1" "\\\$13 = \"\"" +gdb_test "print \$2\[1024\]@1" "\\\$14 = \"\"" + +# Verify out-of-range value history accesses. +gdb_test "print \$2\[(-1LL << 63 - $target_char_rank) - 1\]" \ + "Integer overflow in data location calculation" +gdb_test "print \$2\[(1LL << 63 - $target_char_rank)\]" \ + "Integer overflow in data location calculation" +gdb_test "print \$2\[-1LL << 63\]" \ + "Integer overflow in data location calculation" +gdb_test "print \$2\[(1ULL << 63) - 1\]" \ + "Integer overflow in data location calculation" + +# Sanity-check a copy of an unavailable value. +gdb_test "print \$11" "\\\$15 = <unavailable>" diff --git a/gdb/valarith.c b/gdb/valarith.c index 1dce9d0..7312f0b 100644 --- a/gdb/valarith.c +++ b/gdb/valarith.c @@ -182,6 +182,21 @@ value_subscript (struct value *array, LONGEST index) } index -= *lowerbound; + + /* Do not try to dereference a pointer to an unavailable value. + Instead mock up a new one and give it the original address. */ + struct type *elt_type = check_typedef (tarray->target_type ()); + LONGEST elt_size = type_length_units (elt_type); + if (!value_lazy (array) + && !value_bytes_available (array, elt_size * index, elt_size)) + { + struct value *val = allocate_value (elt_type); + mark_value_bytes_unavailable (val, 0, elt_size); + VALUE_LVAL (val) = lval_memory; + set_value_address (val, value_address (array) + elt_size * index); + return val; + } + array = value_coerce_array (array); } diff --git a/gdb/value.c b/gdb/value.c index 57625b0..fbdb079 100644 --- a/gdb/value.c +++ b/gdb/value.c @@ -185,6 +185,7 @@ struct value initialized (1), stack (0), is_zero (false), + in_history (false), type (type_), enclosing_type (type_) { @@ -239,6 +240,9 @@ struct value otherwise. */ bool is_zero : 1; + /* True if this a value recorded in value history; false otherwise. */ + bool in_history : 1; + /* Location of value (if lval). */ union { @@ -385,7 +389,13 @@ value_bits_available (const struct value *value, { gdb_assert (!value->lazy); - return !ranges_contain (value->unavailable, offset, length); + /* Don't pretend we have anything available there in the history beyond + the boundaries of the value recorded. It's not like inferior memory + where there is actual stuff underneath. */ + ULONGEST val_len = TARGET_CHAR_BIT * value_enclosing_type (value)->length (); + return !((value->in_history + && (offset < 0 || offset + length > val_len)) + || ranges_contain (value->unavailable, offset, length)); } int @@ -1797,6 +1807,7 @@ value_copy (const value *arg) val->modifiable = arg->modifiable; val->stack = arg->stack; val->is_zero = arg->is_zero; + val->in_history = arg->in_history; val->initialized = arg->initialized; val->unavailable = arg->unavailable; val->optimized_out = arg->optimized_out; @@ -1950,6 +1961,10 @@ record_latest_value (struct value *val) a value on the value history never changes. */ if (value_lazy (val)) value_fetch_lazy (val); + + /* Mark the value as recorded in the history for the availability check. */ + val->in_history = true; + /* We preserve VALUE_LVAL so that the user can find out where it was fetched from. This is a bit dubious, because then *&$1 does not just return $1 but the current contents of that location. c'est la vie... */ |