1 files changed, 273 insertions, 0 deletions
diff --git a/lib/VMCore/Globals.cpp b/lib/VMCore/Globals.cpp
new file mode 100644
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+++ b/lib/VMCore/Globals.cpp
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+//===-- Globals.cpp - Implement the GlobalValue & GlobalVariable class ----===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the GlobalValue & GlobalVariable classes for the VMCore
+// library.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Constants.h"
+#include "llvm/GlobalVariable.h"
+#include "llvm/GlobalAlias.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Module.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/Support/LeakDetector.h"
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+//                            GlobalValue Class
+//===----------------------------------------------------------------------===//
+
+/// removeDeadUsersOfConstant - If the specified constantexpr is dead, remove
+/// it.  This involves recursively eliminating any dead users of the
+/// constantexpr.
+static bool removeDeadUsersOfConstant(const Constant *C) {
+  if (isa<GlobalValue>(C)) return false; // Cannot remove this
+
+  while (!C->use_empty()) {
+    const Constant *User = dyn_cast<Constant>(C->use_back());
+    if (!User) return false; // Non-constant usage;
+    if (!removeDeadUsersOfConstant(User))
+      return false; // Constant wasn't dead
+  }
+
+  const_cast<Constant*>(C)->destroyConstant();
+  return true;
+}
+
+/// removeDeadConstantUsers - If there are any dead constant users dangling
+/// off of this global value, remove them.  This method is useful for clients
+/// that want to check to see if a global is unused, but don't want to deal
+/// with potentially dead constants hanging off of the globals.
+void GlobalValue::removeDeadConstantUsers() const {
+  Value::use_const_iterator I = use_begin(), E = use_end();
+  Value::use_const_iterator LastNonDeadUser = E;
+  while (I != E) {
+    if (const Constant *User = dyn_cast<Constant>(*I)) {
+      if (!removeDeadUsersOfConstant(User)) {
+        // If the constant wasn't dead, remember that this was the last live use
+        // and move on to the next constant.
+        LastNonDeadUser = I;
+        ++I;
+      } else {
+        // If the constant was dead, then the iterator is invalidated.
+        if (LastNonDeadUser == E) {
+          I = use_begin();
+          if (I == E) break;
+        } else {
+          I = LastNonDeadUser;
+          ++I;
+        }
+      }
+    } else {
+      LastNonDeadUser = I;
+      ++I;
+    }
+  }
+}
+
+/// Override destroyConstant to make sure it doesn't get called on
+/// GlobalValue's because they shouldn't be treated like other constants.
+void GlobalValue::destroyConstant() {
+  assert(0 && "You can't GV->destroyConstant()!");
+  abort();
+}
+
+/// copyAttributesFrom - copy all additional attributes (those not needed to
+/// create a GlobalValue) from the GlobalValue Src to this one.
+void GlobalValue::copyAttributesFrom(const GlobalValue *Src) {
+  setAlignment(Src->getAlignment());
+  setSection(Src->getSection());
+  setVisibility(Src->getVisibility());
+}
+
+
+//===----------------------------------------------------------------------===//
+// GlobalVariable Implementation
+//===----------------------------------------------------------------------===//
+
+GlobalVariable::GlobalVariable(const Type *Ty, bool constant, LinkageTypes Link,
+                               Constant *InitVal, const std::string &Name,
+                               Module *ParentModule, bool ThreadLocal, 
+                               unsigned AddressSpace)
+  : GlobalValue(PointerType::get(Ty, AddressSpace), Value::GlobalVariableVal,
+                OperandTraits<GlobalVariable>::op_begin(this),
+                InitVal != 0, Link, Name),
+    isConstantGlobal(constant), isThreadLocalSymbol(ThreadLocal) {
+  if (InitVal) {
+    assert(InitVal->getType() == Ty &&
+           "Initializer should be the same type as the GlobalVariable!");
+    Op<0>() = InitVal;
+  }
+
+  LeakDetector::addGarbageObject(this);
+
+  if (ParentModule)
+    ParentModule->getGlobalList().push_back(this);
+}
+
+GlobalVariable::GlobalVariable(const Type *Ty, bool constant, LinkageTypes Link,
+                               Constant *InitVal, const std::string &Name,
+                               GlobalVariable *Before, bool ThreadLocal,
+                               unsigned AddressSpace)
+  : GlobalValue(PointerType::get(Ty, AddressSpace), Value::GlobalVariableVal,
+                OperandTraits<GlobalVariable>::op_begin(this),
+                InitVal != 0, Link, Name),
+    isConstantGlobal(constant), isThreadLocalSymbol(ThreadLocal) {
+  if (InitVal) {
+    assert(InitVal->getType() == Ty &&
+           "Initializer should be the same type as the GlobalVariable!");
+    Op<0>() = InitVal;
+  }
+  
+  LeakDetector::addGarbageObject(this);
+  
+  if (Before)
+    Before->getParent()->getGlobalList().insert(Before, this);
+}
+
+void GlobalVariable::setParent(Module *parent) {
+  if (getParent())
+    LeakDetector::addGarbageObject(this);
+  Parent = parent;
+  if (getParent())
+    LeakDetector::removeGarbageObject(this);
+}
+
+void GlobalVariable::removeFromParent() {
+  getParent()->getGlobalList().remove(this);
+}
+
+void GlobalVariable::eraseFromParent() {
+  getParent()->getGlobalList().erase(this);
+}
+
+void GlobalVariable::replaceUsesOfWithOnConstant(Value *From, Value *To,
+                                                 Use *U) {
+  // If you call this, then you better know this GVar has a constant
+  // initializer worth replacing. Enforce that here.
+  assert(getNumOperands() == 1 &&
+         "Attempt to replace uses of Constants on a GVar with no initializer");
+
+  // And, since you know it has an initializer, the From value better be
+  // the initializer :)
+  assert(getOperand(0) == From &&
+         "Attempt to replace wrong constant initializer in GVar");
+
+  // And, you better have a constant for the replacement value
+  assert(isa<Constant>(To) &&
+         "Attempt to replace GVar initializer with non-constant");
+
+  // Okay, preconditions out of the way, replace the constant initializer.
+  this->setOperand(0, cast<Constant>(To));
+}
+
+/// copyAttributesFrom - copy all additional attributes (those not needed to
+/// create a GlobalVariable) from the GlobalVariable Src to this one.
+void GlobalVariable::copyAttributesFrom(const GlobalValue *Src) {
+  assert(isa<GlobalVariable>(Src) && "Expected a GlobalVariable!");
+  GlobalValue::copyAttributesFrom(Src);
+  const GlobalVariable *SrcVar = cast<GlobalVariable>(Src);
+  setThreadLocal(SrcVar->isThreadLocal());
+}
+
+
+//===----------------------------------------------------------------------===//
+// GlobalAlias Implementation
+//===----------------------------------------------------------------------===//
+
+GlobalAlias::GlobalAlias(const Type *Ty, LinkageTypes Link,
+                         const std::string &Name, Constant* aliasee,
+                         Module *ParentModule)
+  : GlobalValue(Ty, Value::GlobalAliasVal, &Op<0>(), 1, Link, Name) {
+  LeakDetector::addGarbageObject(this);
+
+  if (aliasee)
+    assert(aliasee->getType() == Ty && "Alias and aliasee types should match!");
+  Op<0>() = aliasee;
+
+  if (ParentModule)
+    ParentModule->getAliasList().push_back(this);
+}
+
+void GlobalAlias::setParent(Module *parent) {
+  if (getParent())
+    LeakDetector::addGarbageObject(this);
+  Parent = parent;
+  if (getParent())
+    LeakDetector::removeGarbageObject(this);
+}
+
+void GlobalAlias::removeFromParent() {
+  getParent()->getAliasList().remove(this);
+}
+
+void GlobalAlias::eraseFromParent() {
+  getParent()->getAliasList().erase(this);
+}
+
+bool GlobalAlias::isDeclaration() const {
+  const GlobalValue* AV = getAliasedGlobal();
+  if (AV)
+    return AV->isDeclaration();
+  else
+    return false;
+}
+
+void GlobalAlias::setAliasee(Constant *Aliasee) 
+{
+  if (Aliasee)
+    assert(Aliasee->getType() == getType() &&
+           "Alias and aliasee types should match!");
+  
+  setOperand(0, Aliasee);
+}
+
+const GlobalValue *GlobalAlias::getAliasedGlobal() const {
+  const Constant *C = getAliasee();
+  if (C) {
+    if (const GlobalValue *GV = dyn_cast<GlobalValue>(C))
+      return GV;
+    else {
+      const ConstantExpr *CE = 0;
+      if ((CE = dyn_cast<ConstantExpr>(C)) &&
+          (CE->getOpcode() == Instruction::BitCast || 
+           CE->getOpcode() == Instruction::GetElementPtr))
+        return dyn_cast<GlobalValue>(CE->getOperand(0));
+      else
+        assert(0 && "Unsupported aliasee");
+    }
+  }
+  return 0;
+}
+
+const GlobalValue *GlobalAlias::resolveAliasedGlobal(bool stopOnWeak) const {
+  SmallPtrSet<const GlobalValue*, 3> Visited;
+
+  // Check if we need to stop early.
+  if (stopOnWeak && mayBeOverridden())
+    return this;
+
+  const GlobalValue *GV = getAliasedGlobal();
+  Visited.insert(GV);
+
+  // Iterate over aliasing chain, stopping on weak alias if necessary.
+  while (const GlobalAlias *GA = dyn_cast<GlobalAlias>(GV)) {
+    if (stopOnWeak && GA->mayBeOverridden())
+      break;
+
+    GV = GA->getAliasedGlobal();
+
+    if (!Visited.insert(GV))
+      return NULL;
+  }
+
+  return GV;
+}