llvm/lib/VMCore/Value.cpp
Nate Begeman ff155f03bd Move the operator new and operator delete out of line. This fixes an issue with
operator new() referring to the static initTags function, which has to be in the 
same linkage unit as any file including User.h.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51136 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-15 01:23:11 +00:00

377 lines
12 KiB
C++

//===-- 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 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 <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), SubclassData(0), Ty(checkType(ty)),
UseList(0), Name(0) {
if (isa<CallInst>(this) || isa<InvokeInst>(this))
assert((Ty->isFirstClassType() || Ty == Type::VoidTy ||
isa<OpaqueType>(ty) || Ty->getTypeID() == Type::StructTyID) &&
"invalid CallInst type!");
else if (!isa<Constant>(this) && !isa<BasicBlock>(this))
assert((Ty->isFirstClassType() || Ty == Type::VoidTy ||
isa<OpaqueType>(ty)) &&
"Cannot create non-first-class values except for constants!");
}
Value::~Value() {
#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()) {
DOUT << "While deleting: " << *Ty << " %" << getNameStr() << "\n";
for (use_iterator I = use_begin(), E = use_end(); I != E; ++I)
DOUT << "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;
}
/// 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!");
// 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) {
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 (ConstantExpr *CE = dyn_cast<ConstantExpr>(this)) {
if (CE->getOpcode() == Instruction::BitCast) {
if (isa<PointerType>(CE->getOperand(0)->getType()))
return CE->getOperand(0)->stripPointerCasts();
} else if (CE->getOpcode() == Instruction::GetElementPtr) {
for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
if (!CE->getOperand(i)->isNullValue())
return this;
return CE->getOperand(0)->stripPointerCasts();
}
return this;
}
if (BitCastInst *CI = dyn_cast<BitCastInst>(this)) {
if (isa<PointerType>(CI->getOperand(0)->getType()))
return CI->getOperand(0)->stripPointerCasts();
} else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(this)) {
if (GEP->hasAllZeroIndices())
return GEP->getOperand(0)->stripPointerCasts();
}
return this;
}
//===----------------------------------------------------------------------===//
// 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...
}
}
void *User::operator new(size_t s, unsigned Us) {
void *Storage = ::operator new(s + sizeof(Use) * Us);
Use *Start = static_cast<Use*>(Storage);
Use *End = Start + Us;
User *Obj = reinterpret_cast<User*>(End);
Obj->OperandList = Start;
Obj->NumOperands = Us;
Use::initTags(Start, End);
return Obj;
}
void User::operator delete(void *Usr) {
User *Start = static_cast<User*>(Usr);
Use *Storage = static_cast<Use*>(Usr) - Start->NumOperands;
::operator delete(Storage == Start->OperandList
? Storage
: Usr);
}