From 9233b15d01ca62445bfc638f782243988c672e01 Mon Sep 17 00:00:00 2001
From: Jeffrey Yasskin <jyasskin@google.com>
Date: Thu, 11 Feb 2010 06:41:30 +0000
Subject: [PATCH] Fix some of the memcheck errors found in the JIT unittests.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95856 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/DerivedTypes.h           |  1 +
 include/llvm/Support/SourceMgr.h      |  2 +-
 lib/VMCore/LLVMContextImpl.h          | 13 +++++++++++--
 lib/VMCore/Type.cpp                   | 25 +------------------------
 unittests/VMCore/DerivedTypesTest.cpp | 10 ++++++----
 5 files changed, 20 insertions(+), 31 deletions(-)

diff --git a/include/llvm/DerivedTypes.h b/include/llvm/DerivedTypes.h
index c22060852ac..881fbc81e50 100644
--- a/include/llvm/DerivedTypes.h
+++ b/include/llvm/DerivedTypes.h
@@ -496,6 +496,7 @@ public:
 /// OpaqueType - Class to represent abstract types
 ///
 class OpaqueType : public DerivedType {
+  friend class LLVMContextImpl;
   OpaqueType(const OpaqueType &);                   // DO NOT IMPLEMENT
   const OpaqueType &operator=(const OpaqueType &);  // DO NOT IMPLEMENT
   OpaqueType(LLVMContext &C);
diff --git a/include/llvm/Support/SourceMgr.h b/include/llvm/Support/SourceMgr.h
index bed2f138ddb..fd56b16639c 100644
--- a/include/llvm/Support/SourceMgr.h
+++ b/include/llvm/Support/SourceMgr.h
@@ -132,7 +132,7 @@ class SMDiagnostic {
   unsigned ShowLine : 1;
 
 public:
-  SMDiagnostic() : LineNo(0), ColumnNo(0) {}
+  SMDiagnostic() : LineNo(0), ColumnNo(0), ShowLine(0) {}
   SMDiagnostic(const std::string &FN, int Line, int Col,
                const std::string &Msg, const std::string &LineStr,
                bool showline = true)
diff --git a/lib/VMCore/LLVMContextImpl.h b/lib/VMCore/LLVMContextImpl.h
index ccca7892095..f7f4860614a 100644
--- a/lib/VMCore/LLVMContextImpl.h
+++ b/lib/VMCore/LLVMContextImpl.h
@@ -164,7 +164,10 @@ public:
   // Opaque types are not structurally uniqued, so don't use TypeMap.
   typedef SmallPtrSet<const OpaqueType*, 8> OpaqueTypesTy;
   OpaqueTypesTy OpaqueTypes;
-  
+
+  /// Used as an abstract type that will never be resolved.
+  OpaqueType *const AlwaysOpaqueTy;
+
 
   /// ValueHandles - This map keeps track of all of the value handles that are
   /// watching a Value*.  The Value::HasValueHandle bit is used to know
@@ -196,7 +199,12 @@ public:
     Int8Ty(C, 8),
     Int16Ty(C, 16),
     Int32Ty(C, 32),
-    Int64Ty(C, 64) { }
+    Int64Ty(C, 64),
+    AlwaysOpaqueTy(new OpaqueType(C)) {
+    // Make sure the AlwaysOpaqueTy stays alive as long as the Context.
+    AlwaysOpaqueTy->addRef();
+    OpaqueTypes.insert(AlwaysOpaqueTy);
+  }
 
   ~LLVMContextImpl() {
     ExprConstants.freeConstants();
@@ -217,6 +225,7 @@ public:
         delete I->second;
     }
     MDNodeSet.clear();
+    AlwaysOpaqueTy->dropRef();
     for (OpaqueTypesTy::iterator I = OpaqueTypes.begin(), E = OpaqueTypes.end();
         I != E; ++I) {
       (*I)->AbstractTypeUsers.clear();
diff --git a/lib/VMCore/Type.cpp b/lib/VMCore/Type.cpp
index 044de4fb393..cf851987df8 100644
--- a/lib/VMCore/Type.cpp
+++ b/lib/VMCore/Type.cpp
@@ -507,30 +507,7 @@ void DerivedType::dropAllTypeUses() {
   if (NumContainedTys != 0) {
     // The type must stay abstract.  To do this, we insert a pointer to a type
     // that will never get resolved, thus will always be abstract.
-    static Type *AlwaysOpaqueTy = 0;
-    static PATypeHolder* Holder = 0;
-    Type *tmp = AlwaysOpaqueTy;
-    if (llvm_is_multithreaded()) {
-      sys::MemoryFence();
-      if (!tmp) {
-        llvm_acquire_global_lock();
-        tmp = AlwaysOpaqueTy;
-        if (!tmp) {
-          tmp = OpaqueType::get(getContext());
-          PATypeHolder* tmp2 = new PATypeHolder(tmp);
-          sys::MemoryFence();
-          AlwaysOpaqueTy = tmp;
-          Holder = tmp2;
-        }
-      
-        llvm_release_global_lock();
-      }
-    } else if (!AlwaysOpaqueTy) {
-      AlwaysOpaqueTy = OpaqueType::get(getContext());
-      Holder = new PATypeHolder(AlwaysOpaqueTy);
-    } 
-        
-    ContainedTys[0] = AlwaysOpaqueTy;
+    ContainedTys[0] = getContext().pImpl->AlwaysOpaqueTy;
 
     // Change the rest of the types to be Int32Ty's.  It doesn't matter what we
     // pick so long as it doesn't point back to this type.  We choose something
diff --git a/unittests/VMCore/DerivedTypesTest.cpp b/unittests/VMCore/DerivedTypesTest.cpp
index 11b4dffb5f4..2e0450d6e5c 100644
--- a/unittests/VMCore/DerivedTypesTest.cpp
+++ b/unittests/VMCore/DerivedTypesTest.cpp
@@ -18,14 +18,16 @@ namespace {
 
 TEST(OpaqueTypeTest, RegisterWithContext) {
   LLVMContext C;
-  LLVMContextImpl *pImpl = C.pImpl;  
+  LLVMContextImpl *pImpl = C.pImpl;
 
-  EXPECT_EQ(0u, pImpl->OpaqueTypes.size());
+  // 1 refers to the AlwaysOpaqueTy allocated in the Context's constructor and
+  // destroyed in the destructor.
+  EXPECT_EQ(1u, pImpl->OpaqueTypes.size());
   {
     PATypeHolder Type = OpaqueType::get(C);
-    EXPECT_EQ(1u, pImpl->OpaqueTypes.size());
+    EXPECT_EQ(2u, pImpl->OpaqueTypes.size());
   }
-  EXPECT_EQ(0u, pImpl->OpaqueTypes.size());
+  EXPECT_EQ(1u, pImpl->OpaqueTypes.size());
 }
 
 }  // namespace