[lldb][plugin] Use counter directly for number of readers (#139252)
Here we were initializing & locking a shared_mutex in a thread, while
releasing it in the parent which may/often turned out to be a different
thread (shared_mutex::unlock_shared is undefined behavior if called from
a thread that doesn't hold the lock).
Switch to counter to more simply keep track of number of readers and
simply lock/unlock rather than utilizing reader mutex to verify last
freed (and so requiring this matching thread init/destroy behavior).
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp b/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
index 7d0afc0..ffd6f1d 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.cpp
@@ -189,21 +189,20 @@
}
DWARFUnit::ScopedExtractDIEs::ScopedExtractDIEs(DWARFUnit &cu) : m_cu(&cu) {
- m_cu->m_die_array_scoped_mutex.lock_shared();
+ llvm::sys::ScopedLock lock(m_cu->m_die_array_scoped_mutex);
+ ++m_cu->m_die_array_scoped_count;
}
DWARFUnit::ScopedExtractDIEs::~ScopedExtractDIEs() {
if (!m_cu)
return;
- m_cu->m_die_array_scoped_mutex.unlock_shared();
- if (!m_clear_dies || m_cu->m_cancel_scopes)
- return;
- // Be sure no other ScopedExtractDIEs is running anymore.
- llvm::sys::ScopedWriter lock_scoped(m_cu->m_die_array_scoped_mutex);
- llvm::sys::ScopedWriter lock(m_cu->m_die_array_mutex);
- if (m_cu->m_cancel_scopes)
- return;
- m_cu->ClearDIEsRWLocked();
+ llvm::sys::ScopedLock lock(m_cu->m_die_array_scoped_mutex);
+ --m_cu->m_die_array_scoped_count;
+ if (m_cu->m_die_array_scoped_count == 0 && m_clear_dies &&
+ !m_cu->m_cancel_scopes) {
+ llvm::sys::ScopedWriter lock(m_cu->m_die_array_mutex);
+ m_cu->ClearDIEsRWLocked();
+ }
}
DWARFUnit::ScopedExtractDIEs::ScopedExtractDIEs(ScopedExtractDIEs &&rhs)
diff --git a/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h b/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h
index 75a003e..c05bba3 100644
--- a/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h
+++ b/lldb/source/Plugins/SymbolFile/DWARF/DWARFUnit.h
@@ -17,6 +17,7 @@
#include "llvm/DebugInfo/DWARF/DWARFAddressRange.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugAbbrev.h"
#include "llvm/DebugInfo/DWARF/DWARFDebugRnglists.h"
+#include "llvm/Support/Mutex.h"
#include "llvm/Support/RWMutex.h"
#include <atomic>
#include <optional>
@@ -328,7 +329,8 @@
DWARFDebugInfoEntry::collection m_die_array;
mutable llvm::sys::RWMutex m_die_array_mutex;
// It is used for tracking of ScopedExtractDIEs instances.
- mutable llvm::sys::RWMutex m_die_array_scoped_mutex;
+ mutable llvm::sys::Mutex m_die_array_scoped_mutex;
+ mutable int m_die_array_scoped_count = 0;
// ScopedExtractDIEs instances should not call ClearDIEsRWLocked()
// as someone called ExtractDIEsIfNeeded().
std::atomic<bool> m_cancel_scopes;
diff --git a/lldb/test/API/tools/lldb-dap/console/TestDAP_console.py b/lldb/test/API/tools/lldb-dap/console/TestDAP_console.py
index 8642e31..9cdb978 100644
--- a/lldb/test/API/tools/lldb-dap/console/TestDAP_console.py
+++ b/lldb/test/API/tools/lldb-dap/console/TestDAP_console.py
@@ -176,7 +176,7 @@
f"target create --core {core}", context="repl"
)
- output = self.get_important()
+ output = self.get_important(timeout=2.0)
self.assertIn(
"warning: unable to retrieve process ID from minidump file",
output,
