For PR540:

This patch completes the changes for making lli thread-safe. Here's the list
of changes:
* The Support/ThreadSupport* files were removed and replaced with the
  MutexGuard.h file since all ThreadSupport* declared was a Mutex Guard.
  The implementation of MutexGuard.h is now based on sys::Mutex which hides
  its implementation and makes it unnecessary to have the -NoSupport.h and
  -PThreads.h versions of ThreadSupport.

* All places in ExecutionEngine that previously referred to "Mutex" now
  refer to sys::Mutex

* All places in ExecutionEngine that previously referred to "MutexLocker"
  now refer to MutexGuard (this is frivolous but I believe the technically
  correct name for such a class is "Guard" not a "Locker").

These changes passed all of llvm-test. All we need now are some test cases
that actually use multiple threads.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22404 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 68 insertions, 180 deletions

diff --git a/include/llvm/ExecutionEngine/ExecutionEngine.h b/include/llvm/ExecutionEngine/ExecutionEngine.h
index 13bc9ccc13..301b6d6eeb 100644
--- a/include/llvm/ExecutionEngine/ExecutionEngine.h
+++ b/include/llvm/ExecutionEngine/ExecutionEngine.h
@@ -19,6 +19,7 @@
 #include <map>
 #include <cassert>
 #include <string>
+#include "llvm/Support/MutexGuard.h"
 
 namespace llvm {
 
@@ -33,10 +34,9 @@ class TargetData;
 class Type;
 class IntrinsicLowering;
 
-class ExecutionEngine {
-  Module &CurMod;
-  const TargetData *TD;
 
+class ExecutionEngineState {
+private:
   /// GlobalAddressMap - A mapping between LLVM global values and their
   /// actualized version...
   std::map<const GlobalValue*, void *> GlobalAddressMap;
@@ -46,6 +46,24 @@ class ExecutionEngine {
   /// at the address.  This map is not computed unless getGlobalValueAtAddress
   /// is called at some point.
   std::map<void *, const GlobalValue*> GlobalAddressReverseMap;
+
+public:
+  std::map<const GlobalValue*, void *>& getGlobalAddressMap(const MutexGuard& locked) {
+    return GlobalAddressMap;
+  }
+
+  std::map<void *, const GlobalValue*>& getGlobalAddressReverseMap(const MutexGuard& locked) {
+    return GlobalAddressReverseMap;
+  }
+};
+
+
+class ExecutionEngine {
+  Module &CurMod;
+  const TargetData *TD;
+
+  ExecutionEngineState state;
+
 protected:
   ModuleProvider *MP;
 
@@ -54,6 +72,10 @@ protected:
   }
 
 public:
+  /// lock - This lock is protects the ExecutionEngine, JIT, JITResolver and JITEmitter classes.
+  /// It must be held while changing the internal state of any of those classes.
+  sys::Mutex lock; // Used to make this class and subclasses thread-safe
+
   ExecutionEngine(ModuleProvider *P);
   ExecutionEngine(Module *M);
   virtual ~ExecutionEngine();
@@ -81,13 +103,15 @@ public:
 
 
   void addGlobalMapping(const GlobalValue *GV, void *Addr) {
-    void *&CurVal = GlobalAddressMap[GV];
+    MutexGuard locked(lock);
+
+    void *&CurVal = state.getGlobalAddressMap(locked)[GV];
     assert((CurVal == 0 || Addr == 0) && "GlobalMapping already established!");
     CurVal = Addr;
 
     // If we are using the reverse mapping, add it too
-    if (!GlobalAddressReverseMap.empty()) {
-      const GlobalValue *&V = GlobalAddressReverseMap[Addr];
+    if (!state.getGlobalAddressReverseMap(locked).empty()) {
+      const GlobalValue *&V = state.getGlobalAddressReverseMap(locked)[Addr];
       assert((V == 0 || GV == 0) && "GlobalMapping already established!");
       V = GV;
     }
@@ -96,21 +120,25 @@ public:
   /// clearAllGlobalMappings - Clear all global mappings and start over again
   /// use in dynamic compilation scenarios when you want to move globals
   void clearAllGlobalMappings() {
-    GlobalAddressMap.clear();
-    GlobalAddressReverseMap.clear();
+    MutexGuard locked(lock);
+
+    state.getGlobalAddressMap(locked).clear();
+    state.getGlobalAddressReverseMap(locked).clear();
   }
 
   /// updateGlobalMapping - Replace an existing mapping for GV with a new
   /// address.  This updates both maps as required.
   void updateGlobalMapping(const GlobalValue *GV, void *Addr) {
-    void *&CurVal = GlobalAddressMap[GV];
-    if (CurVal && !GlobalAddressReverseMap.empty())
-      GlobalAddressReverseMap.erase(CurVal);
+    MutexGuard locked(lock);
+
+    void *&CurVal = state.getGlobalAddressMap(locked)[GV];
+    if (CurVal && !state.getGlobalAddressReverseMap(locked).empty())
+      state.getGlobalAddressReverseMap(locked).erase(CurVal);
     CurVal = Addr;
 
     // If we are using the reverse mapping, add it too
-    if (!GlobalAddressReverseMap.empty()) {
-      const GlobalValue *&V = GlobalAddressReverseMap[Addr];
+    if (!state.getGlobalAddressReverseMap(locked).empty()) {
+      const GlobalValue *&V = state.getGlobalAddressReverseMap(locked)[Addr];
       assert((V == 0 || GV == 0) && "GlobalMapping already established!");
       V = GV;
     }
@@ -120,8 +148,10 @@ public:
   /// global value if it is available, otherwise it returns null.
   ///
   void *getPointerToGlobalIfAvailable(const GlobalValue *GV) {
-    std::map<const GlobalValue*, void*>::iterator I = GlobalAddressMap.find(GV);
-    return I != GlobalAddressMap.end() ? I->second : 0;
+    MutexGuard locked(lock);
+
+    std::map<const GlobalValue*, void*>::iterator I = state.getGlobalAddressMap(locked).find(GV);
+    return I != state.getGlobalAddressMap(locked).end() ? I->second : 0;
   }
 
   /// getPointerToGlobal - This returns the address of the specified global
diff --git a/include/llvm/Support/MutexGuard.h b/include/llvm/Support/MutexGuard.h
index bed1a9cec7..24bbbe1bb3 100644
--- a/include/llvm/Support/MutexGuard.h
+++ b/include/llvm/Support/MutexGuard.h
@@ -1,4 +1,4 @@
-//===-- Support/ThreadSupport.h - Generic threading support -----*- C++ -*-===//
+//===-- Support/MutexGuard.h - Acquire/Release Mutex In Scope ---*- C++ -*-===//
 // 
 //                     The LLVM Compiler Infrastructure
 //
@@ -7,36 +7,35 @@
 // 
 //===----------------------------------------------------------------------===//
 //
-// This file defines platform-agnostic interfaces that can be used to write
-// multi-threaded programs.  Autoconf is used to chose the correct
-// implementation of these interfaces, or default to a non-thread-capable system
-// if no matching system support is available.
+// 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_THREADSUPPORT_H
-#define LLVM_SUPPORT_THREADSUPPORT_H
+#ifndef LLVM_SUPPORT_MUTEXGUARD_H
+#define LLVM_SUPPORT_MUTEXGUARD_H
 
-#undef HAVE_PTHREAD_MUTEX_LOCK
-
-#ifdef HAVE_PTHREAD_MUTEX_LOCK
-#include "llvm/Support/ThreadSupport-PThreads.h"
-#else
-#include "llvm/Support/ThreadSupport-NoSupport.h"
-#endif // If no system support is available
+#include <llvm/System/Mutex.h>
 
 namespace llvm {
-  /// MutexLocker - Instances of this class acquire a given Lock when
-  /// constructed and hold that lock until destruction.
-  ///
-  class MutexLocker {
-    Mutex &M;
-    MutexLocker(const MutexLocker &);    // DO NOT IMPLEMENT
-    void operator=(const MutexLocker &); // DO NOT IMPLEMENT
+  /// 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:
-    MutexLocker(Mutex &m) : M(m) { M.acquire(); }
-    ~MutexLocker() { M.release(); }
+    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 // SUPPORT_THREADSUPPORT_H
+#endif // LLVM_SUPPORT_MUTEXGUARD_H
diff --git a/include/llvm/Support/ThreadSupport-NoSupport.h b/include/llvm/Support/ThreadSupport-NoSupport.h
deleted file mode 100644
index 058f82b41f..0000000000
--- a/include/llvm/Support/ThreadSupport-NoSupport.h
+++ /dev/null
@@ -1,34 +0,0 @@
-//===-- llvm/Support/ThreadSupport-NoSupport.h - Generic Impl ---*- 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 generic ThreadSupport implementation used when there is
-// no supported threading mechanism on the current system.  Users should never
-// #include this file directly!
-//
-//===----------------------------------------------------------------------===//
-
-// Users should never #include this file directly!  As such, no include guards
-// are needed.
-
-#ifndef LLVM_SUPPORT_THREADSUPPORT_H
-#error "Code should not #include Support/ThreadSupport-NoSupport.h directly!"
-#endif
-
-namespace llvm {
-  /// Mutex - This class allows user code to protect variables shared between
-  /// threads.  It implements a "recursive" mutex, to simplify user code.
-  ///
-  /// Since there is no platform support for _creating threads_, the non-thread
-  /// implementation of this class is a noop.
-  ///
-  struct Mutex {
-    void acquire () {}
-    void release () {}
-  };
-}
diff --git a/include/llvm/Support/ThreadSupport-PThreads.h b/include/llvm/Support/ThreadSupport-PThreads.h
deleted file mode 100644
index 84c6fac588..0000000000
--- a/include/llvm/Support/ThreadSupport-PThreads.h
+++ /dev/null
@@ -1,65 +0,0 @@
-//===-- llvm/Support/ThreadSupport-PThreads.h - PThreads support *- 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 pthreads implementations of the generic threading
-// mechanisms.  Users should never #include this file directly!
-//
-//===----------------------------------------------------------------------===//
-
-// Users should never #include this file directly!  As such, no include guards
-// are needed.
-
-#ifndef LLVM_SUPPORT_THREADSUPPORT_H
-#error "Code should not #include Support/ThreadSupport/PThreads.h directly!"
-#endif
-
-#include <pthread.h>
-
-namespace llvm {
-
-  /// Mutex - This class allows user code to protect variables shared between
-  /// threads.  It implements a "recursive" mutex, to simplify user code.
-  ///
-  class Mutex {
-    pthread_mutex_t mutex;
-    Mutex(const Mutex &);           // DO NOT IMPLEMENT
-    void operator=(const Mutex &);  // DO NOT IMPLEMENT
-  public:
-    Mutex() {
-      // Initialize the mutex as a recursive mutex
-      pthread_mutexattr_t Attr;
-      int errorcode = pthread_mutexattr_init(&Attr);
-      assert(errorcode == 0);
-
-      errorcode = pthread_mutexattr_settype(&Attr, PTHREAD_MUTEX_RECURSIVE);
-      assert(errorcode == 0);
-
-      errorcode = pthread_mutex_init(&mutex, &Attr);
-      assert(errorcode == 0);
-
-      errorcode = pthread_mutexattr_destroy(&Attr);
-      assert(errorcode == 0);
-    }
-
-    ~Mutex() {
-      int errorcode = pthread_mutex_destroy(&mutex);
-      assert(errorcode == 0);
-    }
-
-    void acquire () {
-      int errorcode = pthread_mutex_lock(&mutex);
-      assert(errorcode == 0);
-    }
-
-    void release () {
-      int errorcode = pthread_mutex_unlock(&mutex);
-      assert(errorcode == 0);
-    }
-  };
-} // end namespace llvm
diff --git a/include/llvm/Support/ThreadSupport.h.in b/include/llvm/Support/ThreadSupport.h.in
deleted file mode 100644
index bed1a9cec7..0000000000
--- a/include/llvm/Support/ThreadSupport.h.in
+++ /dev/null
@@ -1,42 +0,0 @@
-//===-- Support/ThreadSupport.h - Generic threading support -----*- 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 platform-agnostic interfaces that can be used to write
-// multi-threaded programs.  Autoconf is used to chose the correct
-// implementation of these interfaces, or default to a non-thread-capable system
-// if no matching system support is available.
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef LLVM_SUPPORT_THREADSUPPORT_H
-#define LLVM_SUPPORT_THREADSUPPORT_H
-
-#undef HAVE_PTHREAD_MUTEX_LOCK
-
-#ifdef HAVE_PTHREAD_MUTEX_LOCK
-#include "llvm/Support/ThreadSupport-PThreads.h"
-#else
-#include "llvm/Support/ThreadSupport-NoSupport.h"
-#endif // If no system support is available
-
-namespace llvm {
-  /// MutexLocker - Instances of this class acquire a given Lock when
-  /// constructed and hold that lock until destruction.
-  ///
-  class MutexLocker {
-    Mutex &M;
-    MutexLocker(const MutexLocker &);    // DO NOT IMPLEMENT
-    void operator=(const MutexLocker &); // DO NOT IMPLEMENT
-  public:
-    MutexLocker(Mutex &m) : M(m) { M.acquire(); }
-    ~MutexLocker() { M.release(); }
-  };
-}
-
-#endif // SUPPORT_THREADSUPPORT_H