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* [binutils-gdb] [gdb/go] 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=4c4d769ab7b01dab8ff8c66209f992de98095a00
commit 4c4d769ab7b01dab8ff8c66209f992de98095a00
Author: Tom de Vries <tdevries@suse.de>
Date: Sat Jun 4 13:17:33 2022 +0200
[gdb/go] Fix literal truncation
Make sure we error out on overflow instead of truncating in all cases.
The current implementation of parse_number contains a comment about PR16377,
but that's related to C-like languages. In absence of information of whether
the same fix is needed for go, take the conservative approach and keep
behaviour for decimals unchanged.
Tested on x86_64-linux, with a build with --enable-targets=all.
Diff:
---
gdb/go-exp.y | 95 ++++++++++-----------------------
gdb/testsuite/gdb.base/parse_number.exp | 2 +-
2 files changed, 30 insertions(+), 67 deletions(-)
diff --git a/gdb/go-exp.y b/gdb/go-exp.y
index 1b9b6ea7e90..f786ec20171 100644
--- a/gdb/go-exp.y
+++ b/gdb/go-exp.y
@@ -649,7 +649,6 @@ parse_number (struct parser_state *par_state,
{
ULONGEST n = 0;
ULONGEST prevn = 0;
- ULONGEST un;
int i = 0;
int c;
@@ -662,10 +661,6 @@ parse_number (struct parser_state *par_state,
/* We have found a "L" or "U" suffix. */
int found_suffix = 0;
- ULONGEST high_bit;
- struct type *signed_type;
- struct type *unsigned_type;
-
if (parsed_float)
{
const struct builtin_go_type *builtin_go_types
@@ -777,18 +772,12 @@ parse_number (struct parser_state *par_state,
if (i >= base)
return ERROR; /* Invalid digit in this base. */
- /* Portably test for overflow (only works for nonzero values, so make
- a second check for zero). FIXME: Can't we just make n and prevn
- unsigned and avoid this? */
- if (c != 'l' && c != 'u' && (prevn >= n) && n != 0)
- unsigned_p = 1; /* Try something unsigned. */
-
- /* Portably test for unsigned overflow.
- FIXME: This check is wrong; for example it doesn't find overflow
- on 0x123456789 when LONGEST is 32 bits. */
- if (c != 'l' && c != 'u' && n != 0)
+ if (c != 'l' && c != 'u')
{
- if ((unsigned_p && prevn >= n))
+ /* Test for overflow. */
+ if (n == 0 && prevn == 0)
+ ;
+ else if (prevn >= n)
error (_("Numeric constant too large."));
}
prevn = n;
@@ -806,57 +795,31 @@ parse_number (struct parser_state *par_state,
the case where it is we just always shift the value more than
once, with fewer bits each time. */
- un = n >> 2;
- if (long_p == 0
- && (un >> (gdbarch_int_bit (par_state->gdbarch ()) - 2)) == 0)
- {
- high_bit
- = ((ULONGEST)1) << (gdbarch_int_bit (par_state->gdbarch ()) - 1);
-
- /* A large decimal (not hex or octal) constant (between INT_MAX
- and UINT_MAX) is a long or unsigned long, according to ANSI,
- never an unsigned int, but this code treats it as unsigned
- int. This probably should be fixed. GCC gives a warning on
- such constants. */
-
- unsigned_type = parse_type (par_state)->builtin_unsigned_int;
- signed_type = parse_type (par_state)->builtin_int;
- }
- else if (long_p <= 1
- && (un >> (gdbarch_long_bit (par_state->gdbarch ()) - 2)) == 0)
- {
- high_bit
- = ((ULONGEST)1) << (gdbarch_long_bit (par_state->gdbarch ()) - 1);
- unsigned_type = parse_type (par_state)->builtin_unsigned_long;
- signed_type = parse_type (par_state)->builtin_long;
- }
+ int int_bits = gdbarch_int_bit (par_state->gdbarch ());
+ int long_bits = gdbarch_long_bit (par_state->gdbarch ());
+ int long_long_bits = gdbarch_long_long_bit (par_state->gdbarch ());
+ bool have_signed = !unsigned_p;
+ bool have_int = long_p == 0;
+ bool have_long = long_p <= 1;
+ if (have_int && have_signed && fits_in_type (1, n, int_bits, true))
+ putithere->typed_val_int.type = parse_type (par_state)->builtin_int;
+ else if (have_int && fits_in_type (1, n, int_bits, false))
+ putithere->typed_val_int.type
+ = parse_type (par_state)->builtin_unsigned_int;
+ else if (have_long && have_signed && fits_in_type (1, n, long_bits, true))
+ putithere->typed_val_int.type = parse_type (par_state)->builtin_long;
+ else if (have_long && fits_in_type (1, n, long_bits, false))
+ putithere->typed_val_int.type
+ = parse_type (par_state)->builtin_unsigned_long;
+ else if (have_signed && fits_in_type (1, n, long_long_bits, true))
+ putithere->typed_val_int.type
+ = parse_type (par_state)->builtin_long_long;
+ else if (fits_in_type (1, n, long_long_bits, false))
+ putithere->typed_val_int.type
+ = parse_type (par_state)->builtin_unsigned_long_long;
else
- {
- int shift;
- if (sizeof (ULONGEST) * HOST_CHAR_BIT
- < gdbarch_long_long_bit (par_state->gdbarch ()))
- /* A long long does not fit in a LONGEST. */
- shift = (sizeof (ULONGEST) * HOST_CHAR_BIT - 1);
- else
- shift = (gdbarch_long_long_bit (par_state->gdbarch ()) - 1);
- high_bit = (ULONGEST) 1 << shift;
- unsigned_type = parse_type (par_state)->builtin_unsigned_long_long;
- signed_type = parse_type (par_state)->builtin_long_long;
- }
-
- putithere->typed_val_int.val = n;
-
- /* If the high bit of the worked out type is set then this number
- has to be unsigned. */
-
- if (unsigned_p || (n & high_bit))
- {
- putithere->typed_val_int.type = unsigned_type;
- }
- else
- {
- putithere->typed_val_int.type = signed_type;
- }
+ error (_("Numeric constant too large."));
+ putithere->typed_val_int.val = n;
return INT;
}
diff --git a/gdb/testsuite/gdb.base/parse_number.exp b/gdb/testsuite/gdb.base/parse_number.exp
index 87554ccf995..bedb4d64c5a 100644
--- a/gdb/testsuite/gdb.base/parse_number.exp
+++ b/gdb/testsuite/gdb.base/parse_number.exp
@@ -214,7 +214,7 @@ proc parse_number { lang n } {
return [list "unsigned long long" $n]
} else {
# Overflow.
- if { [c_like $lang] } {
+ if { [c_like $lang] || $lang == "go" } {
return [list $re_overflow $re_overflow]
} else {
# Some truncated value or re_overflow, should be re_overflow.
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