//===-- Value.cpp - Implement the Value class -----------------------------===//
-//
+//
// 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 is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
//===----------------------------------------------------------------------===//
//
-// This file implements the Value and User classes.
+// 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/Operator.h"
#include "llvm/Module.h"
-#include "llvm/SymbolTable.h"
+#include "llvm/Metadata.h"
+#include "llvm/ValueSymbolTable.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/LeakDetector.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/ValueHandle.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/System/RWMutex.h"
+#include "llvm/System/Threading.h"
+#include "llvm/ADT/DenseMap.h"
#include <algorithm>
-#include <iostream>
using namespace llvm;
//===----------------------------------------------------------------------===//
return Ty;
}
-Value::Value(const Type *ty, unsigned scid, const std::string &name)
- : SubclassID(scid), SubclassData(0), Ty(checkType(ty)),
- UseList(0), Name(name) {
- if (!isa<Constant>(this) && !isa<BasicBlock>(this))
- assert((Ty->isFirstClassType() || Ty == Type::VoidTy ||
+Value::Value(const Type *ty, unsigned scid)
+ : SubclassID(scid), HasValueHandle(0), SubclassOptionalData(0),
+ SubclassData(0), VTy(checkType(ty)),
+ UseList(0), Name(0) {
+ if (isa<CallInst>(this) || isa<InvokeInst>(this))
+ assert((VTy->isFirstClassType() ||
+ VTy == Type::getVoidTy(ty->getContext()) ||
+ isa<OpaqueType>(ty) || VTy->getTypeID() == Type::StructTyID) &&
+ "invalid CallInst type!");
+ else if (!isa<Constant>(this) && !isa<BasicBlock>(this))
+ assert((VTy->isFirstClassType() ||
+ VTy == Type::getVoidTy(ty->getContext()) ||
isa<OpaqueType>(ty)) &&
"Cannot create non-first-class values except for constants!");
- if (ty == Type::VoidTy)
- assert(name.empty() && "Cannot have named void values!");
}
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
+ // still being referenced. The value in question should be printed as
// a <badref>
//
- if (use_begin() != use_end()) {
- std::cerr << "While deleting: " << *Ty << " %" << Name << "\n";
+ if (!use_empty()) {
+ errs() << "While deleting: " << *VTy << " %" << getNameStr() << "\n";
for (use_iterator I = use_begin(), E = use_end(); I != E; ++I)
- std::cerr << "Use still stuck around after Def is destroyed:"
- << **I << "\n";
+ errs() << "Use still stuck around after Def is destroyed:"
+ << **I << "\n";
}
#endif
- assert(use_begin() == use_end() && "Uses remain when a value is destroyed!");
+ 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);
}
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
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 if (NamedMDNode *N = dyn_cast<NamedMDNode>(V)) {
+ if (Module *P = N->getParent()) {
+ ST = &P->getValueSymbolTable();
+ }
+ } else if (isa<MDString>(V))
+ return true;
+ else {
+ assert(isa<Constant>(V) && "Unknown value type!");
+ return true; // no name is setable for this.
+ }
+ return false;
+}
-void Value::setName(const std::string &name) {
- if (Name == name) return; // Name is already set.
+StringRef Value::getName() const {
+ // Make sure the empty string is still a C string. For historical reasons,
+ // some clients want to call .data() on the result and expect it to be null
+ // terminated.
+ if (!Name) return StringRef("", 0);
+ return Name->getKey();
+}
+
+std::string Value::getNameStr() const {
+ return getName().str();
+}
+
+void Value::setName(const Twine &NewName) {
+ SmallString<32> NameData;
+ NewName.toVector(NameData);
+
+ const char *NameStr = NameData.data();
+ unsigned NameLen = NameData.size();
+ // Name isn't changing?
+ if (getName() == StringRef(NameStr, NameLen))
+ return;
+
+ assert(getType() != Type::getVoidTy(getContext()) &&
+ "Cannot assign a name to void values!");
+
// Get the symbol table to update for this object.
- SymbolTable *ST = 0;
- if (Instruction *I = dyn_cast<Instruction>(this)) {
- if (BasicBlock *P = I->getParent())
- if (Function *PP = P->getParent())
- ST = &PP->getSymbolTable();
- } else if (BasicBlock *BB = dyn_cast<BasicBlock>(this)) {
- if (Function *P = BB->getParent()) ST = &P->getSymbolTable();
- } else if (GlobalValue *GV = dyn_cast<GlobalValue>(this)) {
- if (Module *P = GV->getParent()) ST = &P->getSymbolTable();
- } else if (Argument *A = dyn_cast<Argument>(this)) {
- if (Function *P = A->getParent()) ST = &P->getSymbolTable();
- } else {
- assert(isa<Constant>(this) && "Unknown value type!");
- return; // no name is setable for this.
- }
-
- if (!ST) // No symbol table to update? Just do the change.
- Name = name;
- else if (hasName()) {
- if (!name.empty()) { // Replacing name.
- ST->changeName(this, name);
- } else { // Transitioning from hasName -> noname.
- ST->remove(this);
- Name.clear();
+ 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;
}
- } else { // Transitioning from noname -> hasName.
- Name = name;
- ST->insert(this);
+
+ if (Name)
+ 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()) {
+ // Remove old name.
+ ST->removeValueName(Name);
+ Name->Destroy();
+ Name = 0;
+
+ if (NameLen == 0)
+ return;
+ }
+
+ // Name is changing to something new.
+ Name = ST->createValueName(StringRef(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("");
+ 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("");
+ 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
// 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!
+ // constant because they are uniqued.
if (Constant *C = dyn_cast<Constant>(U.getUser())) {
- if (!isa<GlobalValue>(C))
- C->replaceUsesOfWithOnConstant(this, New, true);
- else
- U.set(New);
- } else {
- U.set(New);
+ if (!isa<GlobalValue>(C)) {
+ C->replaceUsesOfWithOnConstant(this, New, &U);
+ continue;
+ }
}
+
+ U.set(New);
}
}
uncheckedReplaceAllUsesWith(New);
}
+Value *Value::stripPointerCasts() {
+ if (!isa<PointerType>(getType()))
+ return this;
+ Value *V = this;
+ do {
+ if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
+ if (!GEP->hasAllZeroIndices())
+ return V;
+ V = GEP->getPointerOperand();
+ } else if (Operator::getOpcode(V) == Instruction::BitCast) {
+ V = cast<Operator>(V)->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 (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
+ V = GEP->getPointerOperand();
+ } else if (Operator::getOpcode(V) == Instruction::BitCast) {
+ V = cast<Operator>(V)->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;
+}
+
+LLVMContext &Value::getContext() const { return VTy->getContext(); }
+
+//===----------------------------------------------------------------------===//
+// 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;
+static ManagedStatic<sys::SmartRWMutex<true> > ValueHandlesLock;
+
+/// 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.
+ sys::SmartScopedReader<true> Reader(*ValueHandlesLock);
+ ValueHandleBase *&Entry = (*ValueHandles)[VP];
+ assert(Entry != 0 && "Value doesn't have any handles?");
+ AddToExistingUseList(&Entry);
+ return;
+ }
+
+ // 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.
+ sys::SmartScopedWriter<true> Writer(*ValueHandlesLock);
+ 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.
+ sys::SmartScopedWriter<true> Writer(*ValueHandlesLock);
+ 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.
+ ValueHandlesLock->reader_acquire();
+ ValueHandleBase *Entry = (*ValueHandles)[V];
+ ValueHandlesLock->reader_release();
+ 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...
+ errs() << "While deleting: " << *V->getType() << " %" << V->getNameStr()
+ << "\n";
+#endif
+ llvm_unreachable("An asserting value handle still pointed to this"
+ " value!");
+ 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.
+ ValueHandlesLock->reader_acquire();
+ ValueHandleBase *Entry = (*ValueHandles)[Old];
+ ValueHandlesLock->reader_release();
+ 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
//===----------------------------------------------------------------------===//
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!");
+ 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?
setOperand(i, To); // Fix it now...
}
}
-
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