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author | Paul Keir <paul.keir@uws.ac.uk> | 2024-02-12 18:15:49 +0000 |
---|---|---|
committer | Patrick Palka <ppalka@redhat.com> | 2024-02-12 18:18:04 -0500 |
commit | 065dddc6e07a917c57c7955db13b1fe77abbcabc (patch) | |
tree | d66655fe863159f63beaa409c1e2eb7aeae927eb | |
parent | 39d989022dd0eacf1a7b95b7b20621acbe717d70 (diff) | |
download | gcc-065dddc6e07a917c57c7955db13b1fe77abbcabc.zip gcc-065dddc6e07a917c57c7955db13b1fe77abbcabc.tar.gz gcc-065dddc6e07a917c57c7955db13b1fe77abbcabc.tar.bz2 |
libstdc++: Fix constexpr basic_string union member [PR113294]
A call to `basic_string::clear()` in the std::string move assignment
operator leads to a constexpr error from an access of inactive union
member `_M_local_buf` in the added test (`test_move()`). Changing
`__str._M_local_buf` to `__str._M_use_local_data()` in
`operator=(basic_string&& __str)` fixes this.
PR libstdc++/113294
libstdc++-v3/ChangeLog:
* include/bits/basic_string.h (basic_string::operator=): Use
_M_use_local_data() instead of _M_local_buf on the moved-from
string.
* testsuite/21_strings/basic_string/modifiers/constexpr.cc
(test_move): New test.
Signed-off-by: Paul Keir <paul.keir@uws.ac.uk>
Reviewed-by: Patrick Palka <ppalka@redhat.com>
Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
-rw-r--r-- | libstdc++-v3/include/bits/basic_string.h | 2 | ||||
-rw-r--r-- | libstdc++-v3/testsuite/21_strings/basic_string/modifiers/constexpr.cc | 14 |
2 files changed, 15 insertions, 1 deletions
diff --git a/libstdc++-v3/include/bits/basic_string.h b/libstdc++-v3/include/bits/basic_string.h index 43efc99..8a695a4 100644 --- a/libstdc++-v3/include/bits/basic_string.h +++ b/libstdc++-v3/include/bits/basic_string.h @@ -909,7 +909,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11 __str._M_capacity(__capacity); } else - __str._M_data(__str._M_local_buf); + __str._M_data(__str._M_use_local_data()); } else // Need to do a deep copy assign(__str); diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/modifiers/constexpr.cc b/libstdc++-v3/testsuite/21_strings/basic_string/modifiers/constexpr.cc index 0e28a6d..d7022af 100644 --- a/libstdc++-v3/testsuite/21_strings/basic_string/modifiers/constexpr.cc +++ b/libstdc++-v3/testsuite/21_strings/basic_string/modifiers/constexpr.cc @@ -50,3 +50,17 @@ test_erasure() } static_assert( test_erasure() ); + +constexpr bool +test_move() +{ + // PR libstdc++/113294 + std::string s1; + std::string s2 = "1234567890123456"; // 16 chars: more than _S_local_capacity + s1 = std::move(s2); + VERIFY( s1 == "1234567890123456" ); + + return true; +} + +static_assert( test_move() ); |