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Fix 64-bit shifts where long only has 32-bit size

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On systems where long has 32-bit size you get these failures:

print 1 << (unsigned long long) 0xffffffffffffffff
Cannot export value 18446744073709551615 as 32-bits unsigned integer (must be between 0 and 4294967295)
(gdb) FAIL: gdb.base/bitshift.exp: lang=c: max-uint64: print 1 << (unsigned long long) 0xffffffffffffffff
print 1 >> (unsigned long long) 0xffffffffffffffff
Cannot export value 18446744073709551615 as 32-bits unsigned integer (must be between 0 and 4294967295)
(gdb) FAIL: gdb.base/bitshift.exp: lang=c: max-uint64: print 1 >> (unsigned long long) 0xffffffffffffffff
print -1 << (unsigned long long) 0xffffffffffffffff
Cannot export value 18446744073709551615 as 32-bits unsigned integer (must be between 0 and 4294967295)
(gdb) FAIL: gdb.base/bitshift.exp: lang=c: max-uint64: print -1 << (unsigned long long) 0xffffffffffffffff
print -1 >> (unsigned long long) 0xffffffffffffffff
Cannot export value 18446744073709551615 as 32-bits unsigned integer (must be between 0 and 4294967295)
(gdb) FAIL: gdb.base/bitshift.exp: lang=c: max-uint64: print -1 >> (unsigned long long) 0xffffffffffffffff

Fixed by changing the number-of-bits variable to ULONGEST.

Approved-By: Tom Tromey <tom@tromey.com>
This commit is contained in:
Hannes Domani 2024-06-11 20:36:51 +02:00
parent 50f4e9c3c3
commit 3dd8c680a8
2 changed files with 16 additions and 4 deletions
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12
gdb/testsuite/gdb.base/bitshift.exp
View File

@ -363,6 +363,18 @@ proc test_shifts {} {
test_rshift_tl $lang \
"print -1 >> [make_uint64 $lang 0xffffffffffffffff]" " = -1"
}
# Check if shift value isn't silently truncated to 32bit.
with_test_prefix "lower-32bit-zero" {
test_lshift_tl $lang \
"print 1 << [make_uint64 $lang 0x100000000]" " = 0"
test_rshift_tl $lang \
"print 1 >> [make_uint64 $lang 0x100000000]" " = 0"
test_lshift_tl $lang \
"print -1 << [make_uint64 $lang 0x100000000]" " = 0"
test_rshift_tl $lang \
"print -1 >> [make_uint64 $lang 0x100000000]" " = -1"
}
}
}

8
gdb/valarith.c
View File

@ -1086,7 +1086,7 @@ type_length_bits (type *type)
static bool
check_valid_shift_count (enum exp_opcode op, type *result_type,
type *shift_count_type, const gdb_mpz &shift_count,
unsigned long &nbits)
ULONGEST &nbits)
{
if (!shift_count_type->is_unsigned ())
{
@ -1112,7 +1112,7 @@ check_valid_shift_count (enum exp_opcode op, type *result_type,
}
}
nbits = shift_count.as_integer<unsigned long> ();
nbits = shift_count.as_integer<ULONGEST> ();
if (nbits >= type_length_bits (result_type))
{
/* In Go, shifting by large amounts is defined. Be silent and
@ -1291,7 +1291,7 @@ scalar_binop (struct value *arg1, struct value *arg2, enum exp_opcode op)
case BINOP_LSH:
{
unsigned long nbits;
ULONGEST nbits;
if (!check_valid_shift_count (op, result_type, type2, v2, nbits))
v = 0;
else
@ -1301,7 +1301,7 @@ scalar_binop (struct value *arg1, struct value *arg2, enum exp_opcode op)
case BINOP_RSH:
{
unsigned long nbits;
ULONGEST nbits;
if (!check_valid_shift_count (op, result_type, type2, v2, nbits))
{
/* Pretend the too-large shift was decomposed in a