Import LLVM, at r72732.

1 files changed, 581 insertions, 0 deletions

diff --git a/lib/VMCore/Value.cpp b/lib/VMCore/Value.cpp
new file mode 100644
index 0000000..3af161f
--- /dev/null
+++ b/lib/VMCore/Value.cpp
@@ -0,0 +1,581 @@
+//===-- Value.cpp - Implement the Value 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 Value, ValueHandle, and User classes.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Constant.h"
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/InstrTypes.h"
+#include "llvm/Instructions.h"
+#include "llvm/Module.h"
+#include "llvm/ValueSymbolTable.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/LeakDetector.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/ValueHandle.h"
+#include "llvm/ADT/DenseMap.h"
+#include <algorithm>
+using namespace llvm;
+
+//===----------------------------------------------------------------------===//
+//                                Value Class
+//===----------------------------------------------------------------------===//
+
+static inline const Type *checkType(const Type *Ty) {
+  assert(Ty && "Value defined with a null type: Error!");
+  return Ty;
+}
+
+Value::Value(const Type *ty, unsigned scid)
+  : SubclassID(scid), HasValueHandle(0), SubclassData(0), VTy(checkType(ty)),
+    UseList(0), Name(0) {
+  if (isa<CallInst>(this) || isa<InvokeInst>(this))
+    assert((VTy->isFirstClassType() || VTy == Type::VoidTy ||
+            isa<OpaqueType>(ty) || VTy->getTypeID() == Type::StructTyID) &&
+           "invalid CallInst  type!");
+  else if (!isa<Constant>(this) && !isa<BasicBlock>(this))
+    assert((VTy->isFirstClassType() || VTy == Type::VoidTy ||
+           isa<OpaqueType>(ty)) &&
+           "Cannot create non-first-class values except for constants!");
+}
+
+Value::~Value() {
+  // Notify all ValueHandles (if present) that this value is going away.
+  if (HasValueHandle)
+    ValueHandleBase::ValueIsDeleted(this);
+  
+#ifndef NDEBUG      // Only in -g mode...
+  // Check to make sure that there are no uses of this value that are still
+  // around when the value is destroyed.  If there are, then we have a dangling
+  // reference and something is wrong.  This code is here to print out what is
+  // still being referenced.  The value in question should be printed as
+  // a <badref>
+  //
+  if (!use_empty()) {
+    cerr << "While deleting: " << *VTy << " %" << getNameStr() << "\n";
+    for (use_iterator I = use_begin(), E = use_end(); I != E; ++I)
+      cerr << "Use still stuck around after Def is destroyed:"
+           << **I << "\n";
+  }
+#endif
+  assert(use_empty() && "Uses remain when a value is destroyed!");
+
+  // If this value is named, destroy the name.  This should not be in a symtab
+  // at this point.
+  if (Name)
+    Name->Destroy();
+  
+  // There should be no uses of this object anymore, remove it.
+  LeakDetector::removeGarbageObject(this);
+}
+
+/// hasNUses - Return true if this Value has exactly N users.
+///
+bool Value::hasNUses(unsigned N) const {
+  use_const_iterator UI = use_begin(), E = use_end();
+
+  for (; N; --N, ++UI)
+    if (UI == E) return false;  // Too few.
+  return UI == E;
+}
+
+/// hasNUsesOrMore - Return true if this value has N users or more.  This is
+/// logically equivalent to getNumUses() >= N.
+///
+bool Value::hasNUsesOrMore(unsigned N) const {
+  use_const_iterator UI = use_begin(), E = use_end();
+
+  for (; N; --N, ++UI)
+    if (UI == E) return false;  // Too few.
+
+  return true;
+}
+
+/// isUsedInBasicBlock - Return true if this value is used in the specified
+/// basic block.
+bool Value::isUsedInBasicBlock(const BasicBlock *BB) const {
+  for (use_const_iterator I = use_begin(), E = use_end(); I != E; ++I) {
+    const Instruction *User = dyn_cast<Instruction>(*I);
+    if (User && User->getParent() == BB)
+      return true;
+  }
+  return false;
+}
+
+
+/// getNumUses - This method computes the number of uses of this Value.  This
+/// is a linear time operation.  Use hasOneUse or hasNUses to check for specific
+/// values.
+unsigned Value::getNumUses() const {
+  return (unsigned)std::distance(use_begin(), use_end());
+}
+
+static bool getSymTab(Value *V, ValueSymbolTable *&ST) {
+  ST = 0;
+  if (Instruction *I = dyn_cast<Instruction>(V)) {
+    if (BasicBlock *P = I->getParent())
+      if (Function *PP = P->getParent())
+        ST = &PP->getValueSymbolTable();
+  } else if (BasicBlock *BB = dyn_cast<BasicBlock>(V)) {
+    if (Function *P = BB->getParent()) 
+      ST = &P->getValueSymbolTable();
+  } else if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
+    if (Module *P = GV->getParent()) 
+      ST = &P->getValueSymbolTable();
+  } else if (Argument *A = dyn_cast<Argument>(V)) {
+    if (Function *P = A->getParent()) 
+      ST = &P->getValueSymbolTable();
+  } else {
+    assert(isa<Constant>(V) && "Unknown value type!");
+    return true;  // no name is setable for this.
+  }
+  return false;
+}
+
+/// getNameStart - Return a pointer to a null terminated string for this name.
+/// Note that names can have null characters within the string as well as at
+/// their end.  This always returns a non-null pointer.
+const char *Value::getNameStart() const {
+  if (Name == 0) return "";
+  return Name->getKeyData();
+}
+
+/// getNameLen - Return the length of the string, correctly handling nul
+/// characters embedded into them.
+unsigned Value::getNameLen() const {
+  return Name ? Name->getKeyLength() : 0;
+}
+
+/// isName - Return true if this value has the name specified by the provided
+/// nul terminated string.
+bool Value::isName(const char *N) const {
+  unsigned InLen = strlen(N);
+  return InLen == getNameLen() && memcmp(getNameStart(), N, InLen) == 0;
+}
+
+
+std::string Value::getNameStr() const {
+  if (Name == 0) return "";
+  return std::string(Name->getKeyData(),
+                     Name->getKeyData()+Name->getKeyLength());
+}
+
+void Value::setName(const std::string &name) {
+  setName(&name[0], name.size());
+}
+
+void Value::setName(const char *Name) {
+  setName(Name, Name ? strlen(Name) : 0);
+}
+
+void Value::setName(const char *NameStr, unsigned NameLen) {
+  if (NameLen == 0 && !hasName()) return;
+  assert(getType() != Type::VoidTy && "Cannot assign a name to void values!");
+  
+  // Get the symbol table to update for this object.
+  ValueSymbolTable *ST;
+  if (getSymTab(this, ST))
+    return;  // Cannot set a name on this value (e.g. constant).
+
+  if (!ST) { // No symbol table to update?  Just do the change.
+    if (NameLen == 0) {
+      // Free the name for this value.
+      Name->Destroy();
+      Name = 0;
+      return;
+    }
+    
+    if (Name) {
+      // Name isn't changing?
+      if (NameLen == Name->getKeyLength() &&
+          !memcmp(Name->getKeyData(), NameStr, NameLen))
+        return;
+      Name->Destroy();
+    }
+    
+    // NOTE: Could optimize for the case the name is shrinking to not deallocate
+    // then reallocated.
+      
+    // Create the new name.
+    Name = ValueName::Create(NameStr, NameStr+NameLen);
+    Name->setValue(this);
+    return;
+  }
+  
+  // NOTE: Could optimize for the case the name is shrinking to not deallocate
+  // then reallocated.
+  if (hasName()) {
+    // Name isn't changing?
+    if (NameLen == Name->getKeyLength() &&
+        !memcmp(Name->getKeyData(), NameStr, NameLen))
+      return;
+
+    // Remove old name.
+    ST->removeValueName(Name);
+    Name->Destroy();
+    Name = 0;
+
+    if (NameLen == 0)
+      return;
+  }
+
+  // Name is changing to something new.
+  Name = ST->createValueName(NameStr, NameLen, this);
+}
+
+
+/// takeName - transfer the name from V to this value, setting V's name to
+/// empty.  It is an error to call V->takeName(V). 
+void Value::takeName(Value *V) {
+  ValueSymbolTable *ST = 0;
+  // If this value has a name, drop it.
+  if (hasName()) {
+    // Get the symtab this is in.
+    if (getSymTab(this, ST)) {
+      // We can't set a name on this value, but we need to clear V's name if
+      // it has one.
+      if (V->hasName()) V->setName(0, 0);
+      return;  // Cannot set a name on this value (e.g. constant).
+    }
+    
+    // Remove old name.
+    if (ST)
+      ST->removeValueName(Name);
+    Name->Destroy();
+    Name = 0;
+  } 
+  
+  // Now we know that this has no name.
+  
+  // If V has no name either, we're done.
+  if (!V->hasName()) return;
+   
+  // Get this's symtab if we didn't before.
+  if (!ST) {
+    if (getSymTab(this, ST)) {
+      // Clear V's name.
+      V->setName(0, 0);
+      return;  // Cannot set a name on this value (e.g. constant).
+    }
+  }
+  
+  // Get V's ST, this should always succed, because V has a name.
+  ValueSymbolTable *VST;
+  bool Failure = getSymTab(V, VST);
+  assert(!Failure && "V has a name, so it should have a ST!"); Failure=Failure;
+  
+  // If these values are both in the same symtab, we can do this very fast.
+  // This works even if both values have no symtab yet.
+  if (ST == VST) {
+    // Take the name!
+    Name = V->Name;
+    V->Name = 0;
+    Name->setValue(this);
+    return;
+  }
+  
+  // Otherwise, things are slightly more complex.  Remove V's name from VST and
+  // then reinsert it into ST.
+  
+  if (VST)
+    VST->removeValueName(V->Name);
+  Name = V->Name;
+  V->Name = 0;
+  Name->setValue(this);
+  
+  if (ST)
+    ST->reinsertValue(this);
+}
+
+
+// uncheckedReplaceAllUsesWith - This is exactly the same as replaceAllUsesWith,
+// except that it doesn't have all of the asserts.  The asserts fail because we
+// are half-way done resolving types, which causes some types to exist as two
+// different Type*'s at the same time.  This is a sledgehammer to work around
+// this problem.
+//
+void Value::uncheckedReplaceAllUsesWith(Value *New) {
+  // Notify all ValueHandles (if present) that this value is going away.
+  if (HasValueHandle)
+    ValueHandleBase::ValueIsRAUWd(this, New);
+ 
+  while (!use_empty()) {
+    Use &U = *UseList;
+    // Must handle Constants specially, we cannot call replaceUsesOfWith on a
+    // constant because they are uniqued.
+    if (Constant *C = dyn_cast<Constant>(U.getUser())) {
+      if (!isa<GlobalValue>(C)) {
+        C->replaceUsesOfWithOnConstant(this, New, &U);
+        continue;
+      }
+    }
+    
+    U.set(New);
+  }
+}
+
+void Value::replaceAllUsesWith(Value *New) {
+  assert(New && "Value::replaceAllUsesWith(<null>) is invalid!");
+  assert(New != this && "this->replaceAllUsesWith(this) is NOT valid!");
+  assert(New->getType() == getType() &&
+         "replaceAllUses of value with new value of different type!");
+
+  uncheckedReplaceAllUsesWith(New);
+}
+
+Value *Value::stripPointerCasts() {
+  if (!isa<PointerType>(getType()))
+    return this;
+  Value *V = this;
+  do {
+    if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
+      if (CE->getOpcode() == Instruction::GetElementPtr) {
+        for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
+          if (!CE->getOperand(i)->isNullValue())
+            return V;
+        V = CE->getOperand(0);
+      } else if (CE->getOpcode() == Instruction::BitCast) {
+        V = CE->getOperand(0);
+      } else {
+        return V;
+      }
+    } else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(V)) {
+      if (!GEP->hasAllZeroIndices())
+        return V;
+      V = GEP->getOperand(0);
+    } else if (BitCastInst *CI = dyn_cast<BitCastInst>(V)) {
+      V = CI->getOperand(0);
+    } else {
+      return V;
+    }
+    assert(isa<PointerType>(V->getType()) && "Unexpected operand type!");
+  } while (1);
+}
+
+Value *Value::getUnderlyingObject() {
+  if (!isa<PointerType>(getType()))
+    return this;
+  Value *V = this;
+  unsigned MaxLookup = 6;
+  do {
+    if (Instruction *I = dyn_cast<Instruction>(V)) {
+      if (!isa<BitCastInst>(I) && !isa<GetElementPtrInst>(I))
+        return V;
+      V = I->getOperand(0);
+    } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
+      if (CE->getOpcode() != Instruction::BitCast &&
+          CE->getOpcode() != Instruction::GetElementPtr)
+        return V;
+      V = CE->getOperand(0);
+    } else {
+      return V;
+    }
+    assert(isa<PointerType>(V->getType()) && "Unexpected operand type!");
+  } while (--MaxLookup);
+  return V;
+}
+
+/// DoPHITranslation - If this value is a PHI node with CurBB as its parent,
+/// return the value in the PHI node corresponding to PredBB.  If not, return
+/// ourself.  This is useful if you want to know the value something has in a
+/// predecessor block.
+Value *Value::DoPHITranslation(const BasicBlock *CurBB, 
+                               const BasicBlock *PredBB) {
+  PHINode *PN = dyn_cast<PHINode>(this);
+  if (PN && PN->getParent() == CurBB)
+    return PN->getIncomingValueForBlock(PredBB);
+  return this;
+}
+
+//===----------------------------------------------------------------------===//
+//                             ValueHandleBase Class
+//===----------------------------------------------------------------------===//
+
+/// ValueHandles - This map keeps track of all of the value handles that are
+/// watching a Value*.  The Value::HasValueHandle bit is used to know whether or
+/// not a value has an entry in this map.
+typedef DenseMap<Value*, ValueHandleBase*> ValueHandlesTy;
+static ManagedStatic<ValueHandlesTy> ValueHandles;
+
+/// AddToExistingUseList - Add this ValueHandle to the use list for VP, where
+/// List is known to point into the existing use list.
+void ValueHandleBase::AddToExistingUseList(ValueHandleBase **List) {
+  assert(List && "Handle list is null?");
+  
+  // Splice ourselves into the list.
+  Next = *List;
+  *List = this;
+  setPrevPtr(List);
+  if (Next) {
+    Next->setPrevPtr(&Next);
+    assert(VP == Next->VP && "Added to wrong list?");
+  }
+}
+
+/// AddToUseList - Add this ValueHandle to the use list for VP.
+void ValueHandleBase::AddToUseList() {
+  assert(VP && "Null pointer doesn't have a use list!");
+  if (VP->HasValueHandle) {
+    // If this value already has a ValueHandle, then it must be in the
+    // ValueHandles map already.
+    ValueHandleBase *&Entry = (*ValueHandles)[VP];
+    assert(Entry != 0 && "Value doesn't have any handles?");
+    return AddToExistingUseList(&Entry);
+  }
+  
+  // Ok, it doesn't have any handles yet, so we must insert it into the
+  // DenseMap.  However, doing this insertion could cause the DenseMap to
+  // reallocate itself, which would invalidate all of the PrevP pointers that
+  // point into the old table.  Handle this by checking for reallocation and
+  // updating the stale pointers only if needed.
+  ValueHandlesTy &Handles = *ValueHandles;
+  const void *OldBucketPtr = Handles.getPointerIntoBucketsArray();
+  
+  ValueHandleBase *&Entry = Handles[VP];
+  assert(Entry == 0 && "Value really did already have handles?");
+  AddToExistingUseList(&Entry);
+  VP->HasValueHandle = true;
+  
+  // If reallocation didn't happen or if this was the first insertion, don't
+  // walk the table.
+  if (Handles.isPointerIntoBucketsArray(OldBucketPtr) || 
+      Handles.size() == 1)
+    return;
+  
+  // Okay, reallocation did happen.  Fix the Prev Pointers.
+  for (ValueHandlesTy::iterator I = Handles.begin(), E = Handles.end();
+       I != E; ++I) {
+    assert(I->second && I->first == I->second->VP && "List invariant broken!");
+    I->second->setPrevPtr(&I->second);
+  }
+}
+
+/// RemoveFromUseList - Remove this ValueHandle from its current use list.
+void ValueHandleBase::RemoveFromUseList() {
+  assert(VP && VP->HasValueHandle && "Pointer doesn't have a use list!");
+
+  // Unlink this from its use list.
+  ValueHandleBase **PrevPtr = getPrevPtr();
+  assert(*PrevPtr == this && "List invariant broken");
+  
+  *PrevPtr = Next;
+  if (Next) {
+    assert(Next->getPrevPtr() == &Next && "List invariant broken");
+    Next->setPrevPtr(PrevPtr);
+    return;
+  }
+  
+  // If the Next pointer was null, then it is possible that this was the last
+  // ValueHandle watching VP.  If so, delete its entry from the ValueHandles
+  // map.
+  ValueHandlesTy &Handles = *ValueHandles;
+  if (Handles.isPointerIntoBucketsArray(PrevPtr)) {
+    Handles.erase(VP);
+    VP->HasValueHandle = false;
+  }
+}
+
+
+void ValueHandleBase::ValueIsDeleted(Value *V) {
+  assert(V->HasValueHandle && "Should only be called if ValueHandles present");
+
+  // Get the linked list base, which is guaranteed to exist since the
+  // HasValueHandle flag is set.
+  ValueHandleBase *Entry = (*ValueHandles)[V];
+  assert(Entry && "Value bit set but no entries exist");
+  
+  while (Entry) {
+    // Advance pointer to avoid invalidation.
+    ValueHandleBase *ThisNode = Entry;
+    Entry = Entry->Next;
+    
+    switch (ThisNode->getKind()) {
+    case Assert:
+#ifndef NDEBUG      // Only in -g mode...
+      cerr << "While deleting: " << *V->getType() << " %" << V->getNameStr()
+           << "\n";
+#endif
+      cerr << "An asserting value handle still pointed to this value!\n";
+      abort();
+    case Weak:
+      // Weak just goes to null, which will unlink it from the list.
+      ThisNode->operator=(0);
+      break;
+    case Callback:
+      // Forward to the subclass's implementation.
+      static_cast<CallbackVH*>(ThisNode)->deleted();
+      break;
+    }
+  }
+  
+  // All callbacks and weak references should be dropped by now.
+  assert(!V->HasValueHandle && "All references to V were not removed?");
+}
+
+
+void ValueHandleBase::ValueIsRAUWd(Value *Old, Value *New) {
+  assert(Old->HasValueHandle &&"Should only be called if ValueHandles present");
+  assert(Old != New && "Changing value into itself!");
+  
+  // Get the linked list base, which is guaranteed to exist since the
+  // HasValueHandle flag is set.
+  ValueHandleBase *Entry = (*ValueHandles)[Old];
+  assert(Entry && "Value bit set but no entries exist");
+  
+  while (Entry) {
+    // Advance pointer to avoid invalidation.
+    ValueHandleBase *ThisNode = Entry;
+    Entry = Entry->Next;
+    
+    switch (ThisNode->getKind()) {
+    case Assert:
+      // Asserting handle does not follow RAUW implicitly.
+      break;
+    case Weak:
+      // Weak goes to the new value, which will unlink it from Old's list.
+      ThisNode->operator=(New);
+      break;
+    case Callback:
+      // Forward to the subclass's implementation.
+      static_cast<CallbackVH*>(ThisNode)->allUsesReplacedWith(New);
+      break;
+    }
+  }
+}
+
+/// ~CallbackVH. Empty, but defined here to avoid emitting the vtable
+/// more than once.
+CallbackVH::~CallbackVH() {}
+
+
+//===----------------------------------------------------------------------===//
+//                                 User Class
+//===----------------------------------------------------------------------===//
+
+// replaceUsesOfWith - Replaces all references to the "From" definition with
+// references to the "To" definition.
+//
+void User::replaceUsesOfWith(Value *From, Value *To) {
+  if (From == To) return;   // Duh what?
+
+  assert((!isa<Constant>(this) || isa<GlobalValue>(this)) &&
+         "Cannot call User::replaceUsesofWith on a constant!");
+
+  for (unsigned i = 0, E = getNumOperands(); i != E; ++i)
+    if (getOperand(i) == From) {  // Is This operand is pointing to oldval?
+      // The side effects of this setOperand call include linking to
+      // "To", adding "this" to the uses list of To, and
+      // most importantly, removing "this" from the use list of "From".
+      setOperand(i, To); // Fix it now...
+    }
+}
+