krytarowski added a comment.
I've tried to build the LLDB code with mechanically * replaced `std::call_once`
-> `llvm::call_once` and `std::once_flag` -> `llvm::once_flag`:
--- /public/llvm/include/llvm/Support/Threading.h 2017-02-05
00:15:00.769574623 +0100
+++ /usr/pkg/include/llvm/Support/Threading.h 2017-02-05 04:14:03.334251557
+0100
@@ -62,12 +62,16 @@
/// This macro is the only way you should define your once flag for LLVM's
/// call_once.
-#define LLVM_DEFINE_ONCE_FLAG(flag) static ::llvm::once_flag flag
+#define LLVM_DEFINE_ONCE_FLAG(flag) static once_flag flag
#else
enum InitStatus { Uninitialized = 0, Wait = 1, Done = 2 };
- typedef volatile sys::cas_flag once_flag;
+ class once_flag {
+ public:
+ once_flag() : status(::llvm::Uninitialized) {};
+ volatile ::llvm::sys::cas_flag status;
+ };
/// This macro is the only way you should define your once flag for LLVM's
/// call_once.
@@ -96,24 +100,24 @@
#else
// For other platforms we use a generic (if brittle) version based on our
// atomics.
- sys::cas_flag old_val = sys::CompareAndSwap(&flag, Wait, Uninitialized);
+ sys::cas_flag old_val = sys::CompareAndSwap(&flag.status, Wait,
Uninitialized);
if (old_val == Uninitialized) {
std::forward<Function>(F)(std::forward<Args>(ArgList)...);
sys::MemoryFence();
TsanIgnoreWritesBegin();
- TsanHappensBefore(&flag);
- flag = Done;
+ TsanHappensBefore(&flag.status);
+ flag.status = Done;
TsanIgnoreWritesEnd();
} else {
// Wait until any thread doing the call has finished.
- sys::cas_flag tmp = flag;
+ sys::cas_flag tmp = flag.status;
sys::MemoryFence();
while (tmp != Done) {
- tmp = flag;
+ tmp = flag.status;
sys::MemoryFence();
}
}
- TsanHappensAfter(&flag);
+ TsanHappensAfter(&flag.status);
#endif
}
- there is one exception, I don't understand:
const DWARFDataExtractor &
SymbolFileDWARF::GetCachedSectionData(lldb::SectionType sect_type,
DWARFDataSegment &data_segment) {
#if 0
llvm::call_once(data_segment.m_flag, &SymbolFileDWARF::LoadSectionData,
this,
sect_type, std::ref(data_segment.m_data));
#else
llvm::call_once(data_segment.m_flag,
[this, sect_type, &data_segment] {
this->LoadSectionData(sect_type, std::ref(data_segment.m_data));
}
);
#endif
return data_segment.m_data;
}
This exception is valid for so far all versions of switches out of
`std::once_flag`.
Repository:
rL LLVM
https://reviews.llvm.org/D29288
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