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* [binutils-gdb] [gdb/fortran] Fix literal truncation
@ 2022-06-04 11:17 Tom de Vries
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From: Tom de Vries @ 2022-06-04 11:17 UTC (permalink / raw)
To: gdb-cvs
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=a2c0d041fdbf9d661099e31629c96cdd666e8b83
commit a2c0d041fdbf9d661099e31629c96cdd666e8b83
Author: Tom de Vries <tdevries@suse.de>
Date: Sat Jun 4 13:17:33 2022 +0200
[gdb/fortran] Fix literal truncation
As mentioned in commit 5b758627a18 ("Make gdb.base/parse_number.exp test all
architectures"):
...
There might be a bug that 32-bit fortran truncates 64-bit values to
32-bit, given "p/x 0xffffffffffffffff" returns "0xffffffff".
...
More concretely, we have:
...
$ for arch in i386:x86-64 i386; do \
gdb -q -batch -ex "set arch $arch" -ex "set lang fortran" \
-ex "p /x 0xffffffffffffffff"; \
done
The target architecture is set to "i386:x86-64".
$1 = 0xffffffffffffffff
The target architecture is set to "i386".
$1 = 0xffffffff
...
Fix this by adding a range check in parse_number in gdb/f-exp.y.
Furthermore, make sure we error out on overflow instead of truncating in all
other cases.
Tested on x86_64-linux.
Diff:
---
gdb/f-exp.y | 31 +++++++++++++++----------------
gdb/testsuite/gdb.base/parse_number.exp | 4 +---
2 files changed, 16 insertions(+), 19 deletions(-)
diff --git a/gdb/f-exp.y b/gdb/f-exp.y
index 90cc2c65c7b..62641083850 100644
--- a/gdb/f-exp.y
+++ b/gdb/f-exp.y
@@ -1076,16 +1076,11 @@ parse_number (struct parser_state *par_state,
n *= base;
n += i;
}
- /* Portably test for overflow (only works for nonzero values, so make
- a second check for zero). */
- if ((prevn >= n) && n != 0)
- unsigned_p=1; /* Try something unsigned */
- /* If range checking enabled, portably test for unsigned overflow. */
- if (RANGE_CHECK && n != 0)
- {
- if ((unsigned_p && prevn >= n))
- range_error (_("Overflow on numeric constant."));
- }
+ /* Test for overflow. */
+ if (prevn == 0 && n == 0)
+ ;
+ else if (RANGE_CHECK && prevn >= n)
+ range_error (_("Overflow on numeric constant."));
prevn = n;
}
@@ -1100,7 +1095,8 @@ parse_number (struct parser_state *par_state,
but too many compilers warn about that, when ints and longs
are the same size. So we shift it twice, with fewer bits
each time, for the same result. */
-
+
+ int bits_available;
if ((gdbarch_int_bit (par_state->gdbarch ())
!= gdbarch_long_bit (par_state->gdbarch ())
&& ((n >> 2)
@@ -1108,19 +1104,22 @@ parse_number (struct parser_state *par_state,
shift warning */
|| long_p)
{
- high_bit = ((ULONGEST)1)
- << (gdbarch_long_bit (par_state->gdbarch ())-1);
+ bits_available = gdbarch_long_bit (par_state->gdbarch ());
unsigned_type = parse_type (par_state)->builtin_unsigned_long;
signed_type = parse_type (par_state)->builtin_long;
- }
+ }
else
{
- high_bit =
- ((ULONGEST)1) << (gdbarch_int_bit (par_state->gdbarch ()) - 1);
+ bits_available = gdbarch_int_bit (par_state->gdbarch ());
unsigned_type = parse_type (par_state)->builtin_unsigned_int;
signed_type = parse_type (par_state)->builtin_int;
}
+ high_bit = ((ULONGEST)1) << (bits_available - 1);
+ if (RANGE_CHECK
+ && ((n >> 2) >> (bits_available - 2)))
+ range_error (_("Overflow on numeric constant."));
+
putithere->typed_val.val = n;
/* If the high bit of the worked out type is set then this number
diff --git a/gdb/testsuite/gdb.base/parse_number.exp b/gdb/testsuite/gdb.base/parse_number.exp
index 638ea342384..87554ccf995 100644
--- a/gdb/testsuite/gdb.base/parse_number.exp
+++ b/gdb/testsuite/gdb.base/parse_number.exp
@@ -176,9 +176,7 @@ proc parse_number { lang n } {
return [list "unsigned long" $n]
} else {
# Overflow.
- # Some truncated value or re_overflow, should be re_overflow.
- return [list "((unsigned )?(int|long)|$re_overflow)" \
- ($any|$re_overflow)]
+ return [list $re_overflow $re_overflow]
}
} else {
if { [c_like $lang] } {
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2022-06-04 11:17 [binutils-gdb] [gdb/fortran] Fix literal truncation Tom de Vries
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