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| author | Ali Tamur <tamur@google.com> | 2019-08-27 18:58:57 -0700 |
|---|---|---|
| committer | Ali Tamur <tamur@google.com> | 2019-09-11 12:21:50 -0700 |
| commit | 9cab7ecda21c6499b0559f6e676fe222e26141be (patch) | |
| tree | 48692643c655d394dfc56b8afa81d738b6821ccf | |
| parent | 67547d896b0593b0fa62e23ac68c483a7e8566e2 (diff) | |
| download | gdb-9cab7ecda21c6499b0559f6e676fe222e26141be.zip gdb-9cab7ecda21c6499b0559f6e676fe222e26141be.tar.gz gdb-9cab7ecda21c6499b0559f6e676fe222e26141be.tar.bz2 | |
Fix float to LONGEST conversion.
The code used to have undefined behaviour when template parameter is float and
host_float is NaN, because it attempted to convert NaN value to LONGEST at the
last statement. This frequently caused crashes on tests that checked "info
all-registers" (at least when the code is compiled with clang; I didn't test
with gdb).
gdb/ChangeLog:
*target-float.c (host_float_ops<T>::to_longest): Update
implementation.
| -rw-r--r-- | gdb/ChangeLog | 5 | ||||
| -rw-r--r-- | gdb/target-float.c | 17 |
2 files changed, 16 insertions, 6 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 3b28884..eccd4ef 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2019-09-11 Ali Tamur <tamur@google.com> + + *gdb/target-float.c (host_float_ops<T>::to_longest): Update + implementation. + 2019-09-11 Christian Biesinger <cbiesinger@google.com> * dbxread.c (read_dbx_symtab): Update. diff --git a/gdb/target-float.c b/gdb/target-float.c index 39abb12..0fd71c0 100644 --- a/gdb/target-float.c +++ b/gdb/target-float.c @@ -1007,13 +1007,18 @@ host_float_ops<T>::to_longest (const gdb_byte *addr, { T host_float; from_target (type, addr, &host_float); - /* Converting an out-of-range value is undefined behavior in C, but we - prefer to return a defined value here. */ - if (host_float > std::numeric_limits<LONGEST>::max()) - return std::numeric_limits<LONGEST>::max(); - if (host_float < std::numeric_limits<LONGEST>::min()) + T min_possible_range = static_cast<T>(std::numeric_limits<LONGEST>::min()); + T max_possible_range = -min_possible_range; + /* host_float can be converted to an integer as long as it's in + the range [min_possible_range, max_possible_range). If not, it is either + too large, or too small, or is NaN; in this case return the maximum or + minimum possible value. */ + if (host_float < max_possible_range && host_float >= min_possible_range) + return static_cast<LONGEST> (host_float); + if (host_float < min_possible_range) return std::numeric_limits<LONGEST>::min(); - return (LONGEST) host_float; + /* This line will be executed if host_float is NaN. */ + return std::numeric_limits<LONGEST>::max(); } /* Convert signed integer VAL to a target floating-number of type TYPE |