1
//===-- Globals.cpp - Implement the GlobalValue & GlobalVariable class ----===//
3
// The LLVM Compiler Infrastructure
5
// This file is distributed under the University of Illinois Open Source
6
// License. See LICENSE.TXT for details.
8
//===----------------------------------------------------------------------===//
10
// This file implements the GlobalValue & GlobalVariable classes for the VMCore
13
//===----------------------------------------------------------------------===//
15
#include "llvm/Constants.h"
16
#include "llvm/GlobalVariable.h"
17
#include "llvm/GlobalAlias.h"
18
#include "llvm/DerivedTypes.h"
19
#include "llvm/Module.h"
20
#include "llvm/ADT/SmallPtrSet.h"
21
#include "llvm/Support/ErrorHandling.h"
22
#include "llvm/Support/LeakDetector.h"
25
//===----------------------------------------------------------------------===//
27
//===----------------------------------------------------------------------===//
29
/// removeDeadUsersOfConstant - If the specified constantexpr is dead, remove
30
/// it. This involves recursively eliminating any dead users of the
32
static bool removeDeadUsersOfConstant(const Constant *C) {
33
if (isa<GlobalValue>(C)) return false; // Cannot remove this
35
while (!C->use_empty()) {
36
const Constant *User = dyn_cast<Constant>(C->use_back());
37
if (!User) return false; // Non-constant usage;
38
if (!removeDeadUsersOfConstant(User))
39
return false; // Constant wasn't dead
42
const_cast<Constant*>(C)->destroyConstant();
46
bool GlobalValue::isMaterializable() const {
47
return getParent() && getParent()->isMaterializable(this);
49
bool GlobalValue::isDematerializable() const {
50
return getParent() && getParent()->isDematerializable(this);
52
bool GlobalValue::Materialize(std::string *ErrInfo) {
53
return getParent()->Materialize(this, ErrInfo);
55
void GlobalValue::Dematerialize() {
56
getParent()->Dematerialize(this);
59
/// removeDeadConstantUsers - If there are any dead constant users dangling
60
/// off of this global value, remove them. This method is useful for clients
61
/// that want to check to see if a global is unused, but don't want to deal
62
/// with potentially dead constants hanging off of the globals.
63
void GlobalValue::removeDeadConstantUsers() const {
64
Value::use_const_iterator I = use_begin(), E = use_end();
65
Value::use_const_iterator LastNonDeadUser = E;
67
if (const Constant *User = dyn_cast<Constant>(*I)) {
68
if (!removeDeadUsersOfConstant(User)) {
69
// If the constant wasn't dead, remember that this was the last live use
70
// and move on to the next constant.
74
// If the constant was dead, then the iterator is invalidated.
75
if (LastNonDeadUser == E) {
91
/// Override destroyConstant to make sure it doesn't get called on
92
/// GlobalValue's because they shouldn't be treated like other constants.
93
void GlobalValue::destroyConstant() {
94
llvm_unreachable("You can't GV->destroyConstant()!");
97
/// copyAttributesFrom - copy all additional attributes (those not needed to
98
/// create a GlobalValue) from the GlobalValue Src to this one.
99
void GlobalValue::copyAttributesFrom(const GlobalValue *Src) {
100
setAlignment(Src->getAlignment());
101
setSection(Src->getSection());
102
setVisibility(Src->getVisibility());
106
//===----------------------------------------------------------------------===//
107
// GlobalVariable Implementation
108
//===----------------------------------------------------------------------===//
110
GlobalVariable::GlobalVariable(const Type *Ty, bool constant, LinkageTypes Link,
111
Constant *InitVal, const Twine &Name,
112
bool ThreadLocal, unsigned AddressSpace)
113
: GlobalValue(PointerType::get(Ty, AddressSpace),
114
Value::GlobalVariableVal,
115
OperandTraits<GlobalVariable>::op_begin(this),
116
InitVal != 0, Link, Name),
117
isConstantGlobal(constant), isThreadLocalSymbol(ThreadLocal) {
119
assert(InitVal->getType() == Ty &&
120
"Initializer should be the same type as the GlobalVariable!");
124
LeakDetector::addGarbageObject(this);
127
GlobalVariable::GlobalVariable(Module &M, const Type *Ty, bool constant,
128
LinkageTypes Link, Constant *InitVal,
130
GlobalVariable *Before, bool ThreadLocal,
131
unsigned AddressSpace)
132
: GlobalValue(PointerType::get(Ty, AddressSpace),
133
Value::GlobalVariableVal,
134
OperandTraits<GlobalVariable>::op_begin(this),
135
InitVal != 0, Link, Name),
136
isConstantGlobal(constant), isThreadLocalSymbol(ThreadLocal) {
138
assert(InitVal->getType() == Ty &&
139
"Initializer should be the same type as the GlobalVariable!");
143
LeakDetector::addGarbageObject(this);
146
Before->getParent()->getGlobalList().insert(Before, this);
148
M.getGlobalList().push_back(this);
151
void GlobalVariable::setParent(Module *parent) {
153
LeakDetector::addGarbageObject(this);
156
LeakDetector::removeGarbageObject(this);
159
void GlobalVariable::removeFromParent() {
160
getParent()->getGlobalList().remove(this);
163
void GlobalVariable::eraseFromParent() {
164
getParent()->getGlobalList().erase(this);
167
void GlobalVariable::replaceUsesOfWithOnConstant(Value *From, Value *To,
169
// If you call this, then you better know this GVar has a constant
170
// initializer worth replacing. Enforce that here.
171
assert(getNumOperands() == 1 &&
172
"Attempt to replace uses of Constants on a GVar with no initializer");
174
// And, since you know it has an initializer, the From value better be
175
// the initializer :)
176
assert(getOperand(0) == From &&
177
"Attempt to replace wrong constant initializer in GVar");
179
// And, you better have a constant for the replacement value
180
assert(isa<Constant>(To) &&
181
"Attempt to replace GVar initializer with non-constant");
183
// Okay, preconditions out of the way, replace the constant initializer.
184
this->setOperand(0, cast<Constant>(To));
187
void GlobalVariable::setInitializer(Constant *InitVal) {
189
if (hasInitializer()) {
194
assert(InitVal->getType() == getType()->getElementType() &&
195
"Initializer type must match GlobalVariable type");
196
if (!hasInitializer())
198
Op<0>().set(InitVal);
202
/// copyAttributesFrom - copy all additional attributes (those not needed to
203
/// create a GlobalVariable) from the GlobalVariable Src to this one.
204
void GlobalVariable::copyAttributesFrom(const GlobalValue *Src) {
205
assert(isa<GlobalVariable>(Src) && "Expected a GlobalVariable!");
206
GlobalValue::copyAttributesFrom(Src);
207
const GlobalVariable *SrcVar = cast<GlobalVariable>(Src);
208
setThreadLocal(SrcVar->isThreadLocal());
212
//===----------------------------------------------------------------------===//
213
// GlobalAlias Implementation
214
//===----------------------------------------------------------------------===//
216
GlobalAlias::GlobalAlias(const Type *Ty, LinkageTypes Link,
217
const Twine &Name, Constant* aliasee,
218
Module *ParentModule)
219
: GlobalValue(Ty, Value::GlobalAliasVal, &Op<0>(), 1, Link, Name) {
220
LeakDetector::addGarbageObject(this);
223
assert(aliasee->getType() == Ty && "Alias and aliasee types should match!");
227
ParentModule->getAliasList().push_back(this);
230
void GlobalAlias::setParent(Module *parent) {
232
LeakDetector::addGarbageObject(this);
235
LeakDetector::removeGarbageObject(this);
238
void GlobalAlias::removeFromParent() {
239
getParent()->getAliasList().remove(this);
242
void GlobalAlias::eraseFromParent() {
243
getParent()->getAliasList().erase(this);
246
bool GlobalAlias::isDeclaration() const {
247
const GlobalValue* AV = getAliasedGlobal();
249
return AV->isDeclaration();
254
void GlobalAlias::setAliasee(Constant *Aliasee)
257
assert(Aliasee->getType() == getType() &&
258
"Alias and aliasee types should match!");
260
setOperand(0, Aliasee);
263
const GlobalValue *GlobalAlias::getAliasedGlobal() const {
264
const Constant *C = getAliasee();
266
if (const GlobalValue *GV = dyn_cast<GlobalValue>(C))
269
const ConstantExpr *CE = 0;
270
if ((CE = dyn_cast<ConstantExpr>(C)) &&
271
(CE->getOpcode() == Instruction::BitCast ||
272
CE->getOpcode() == Instruction::GetElementPtr))
273
return dyn_cast<GlobalValue>(CE->getOperand(0));
275
llvm_unreachable("Unsupported aliasee");
281
const GlobalValue *GlobalAlias::resolveAliasedGlobal(bool stopOnWeak) const {
282
SmallPtrSet<const GlobalValue*, 3> Visited;
284
// Check if we need to stop early.
285
if (stopOnWeak && mayBeOverridden())
288
const GlobalValue *GV = getAliasedGlobal();
291
// Iterate over aliasing chain, stopping on weak alias if necessary.
292
while (const GlobalAlias *GA = dyn_cast<GlobalAlias>(GV)) {
293
if (stopOnWeak && GA->mayBeOverridden())
296
GV = GA->getAliasedGlobal();
298
if (!Visited.insert(GV))