LineageOS/android_external_libcxx
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Fix UB in string.bench.cpp.

Browse Source 
The usage of aligned_storage failed to pass the alignment it wanted,
which caused it to have a larger size and alignment that the
std::string's it was intended to store.

This patch manually specifies the alignment, as well as cleaning up
type alias bugs.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@346779 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Eric Fiselier
2018-11-13 19:16:19 +00:00
parent 10180dc28f
commit 6b8b8a113d
1 changed files with 6 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
benchmarks/string.bench.cpp
View File

@@ -195,21 +195,21 @@ template <class Length>
struct StringMove {
static void run(benchmark::State& state) {
// Keep two object locations and move construct back and forth.
std::aligned_storage<sizeof(std::string)>::type Storage[2];
std::aligned_storage<sizeof(std::string), alignof(std::string)>::type Storage[2];
using S = std::string;
S* Data = reinterpret_cast<S*>(Storage);
size_t I = 0;
new (static_cast<void*>(Data)) std::string(makeString(Length()));
S *newS = new (static_cast<void*>(Storage)) std::string(makeString(Length()));
for (auto _ : state) {
// Switch locations.
I ^= 1;
benchmark::DoNotOptimize(Storage);
// Move construct into the new location,
new (static_cast<void*>(Storage + I)) S(std::move(Data[I ^ 1]));
S *tmpS = new (static_cast<void*>(Storage + I)) S(std::move(*newS));
// then destroy the old one.
Data[I ^ 1].~S();
newS->~S();
newS = tmpS;
}
Data[I].~S();
newS->~S();
}
static std::string name() { return "BM_StringMove" + Length::name(); }