It's not necessary to do rounding for alloca operations when the requested

alignment is equal to the stack alignment.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40004 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 41 insertions, 0 deletions

diff --git a/include/llvm/Support/MutexGuard.h b/include/llvm/Support/MutexGuard.h
new file mode 100644
index 0000000..21c756d
--- /dev/null
+++ b/include/llvm/Support/MutexGuard.h
@@ -0,0 +1,41 @@
+//===-- Support/MutexGuard.h - Acquire/Release Mutex In Scope ---*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines a guard for a block of code that ensures a Mutex is locked
+// upon construction and released upon destruction.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_MUTEXGUARD_H
+#define LLVM_SUPPORT_MUTEXGUARD_H
+
+#include <llvm/System/Mutex.h>
+
+namespace llvm {
+  /// Instances of this class acquire a given Mutex Lock when constructed and
+  /// hold that lock until destruction. The intention is to instantiate one of
+  /// these on the stack at the top of some scope to be assured that C++
+  /// destruction of the object will always release the Mutex and thus avoid
+  /// a host of nasty multi-threading problems in the face of exceptions, etc.
+  /// @brief Guard a section of code with a Mutex.
+  class MutexGuard {
+    sys::Mutex &M;
+    MutexGuard(const MutexGuard &);    // DO NOT IMPLEMENT
+    void operator=(const MutexGuard &); // DO NOT IMPLEMENT
+  public:
+    MutexGuard(sys::Mutex &m) : M(m) { M.acquire(); }
+    ~MutexGuard() { M.release(); }
+    /// holds - Returns true if this locker instance holds the specified lock.
+    /// This is mostly used in assertions to validate that the correct mutex
+    /// is held.
+    bool holds(const sys::Mutex& lock) const { return &M == &lock; }
+  };
+}
+
+#endif // LLVM_SUPPORT_MUTEXGUARD_H