//
//===----------------------------------------------------------------------===//
-#include "llvm/IR/GlobalValue.h"
#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/Triple.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/GlobalAlias.h"
+#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Operator.h"
return F->isMaterializable();
return false;
}
-bool GlobalValue::isDematerializable() const {
- return getParent() && getParent()->isDematerializable(this);
-}
std::error_code GlobalValue::materialize() {
return getParent()->materialize(this);
}
-void GlobalValue::dematerialize() {
- getParent()->dematerialize(this);
-}
-/// Override destroyConstant to make sure it doesn't get called on
+/// Override destroyConstantImpl to make sure it doesn't get called on
/// GlobalValue's because they shouldn't be treated like other constants.
-void GlobalValue::destroyConstant() {
- llvm_unreachable("You can't GV->destroyConstant()!");
+void GlobalValue::destroyConstantImpl() {
+ llvm_unreachable("You can't GV->destroyConstantImpl()!");
+}
+
+Value *GlobalValue::handleOperandChangeImpl(Value *From, Value *To, Use *U) {
+ llvm_unreachable("Unsupported class for handleOperandChange()!");
}
/// copyAttributesFrom - copy all additional attributes (those not needed to
}
void GlobalObject::copyAttributesFrom(const GlobalValue *Src) {
- const auto *GV = cast<GlobalObject>(Src);
- GlobalValue::copyAttributesFrom(GV);
- setAlignment(GV->getAlignment());
- setSection(GV->getSection());
+ GlobalValue::copyAttributesFrom(Src);
+ if (const auto *GV = dyn_cast<GlobalObject>(Src)) {
+ setAlignment(GV->getAlignment());
+ setSection(GV->getSection());
+ }
}
const char *GlobalValue::getSection() const {
return false;
}
+bool GlobalValue::canIncreaseAlignment() const {
+ // Firstly, can only increase the alignment of a global if it
+ // is a strong definition.
+ if (!isStrongDefinitionForLinker())
+ return false;
+
+ // It also has to either not have a section defined, or, not have
+ // alignment specified. (If it is assigned a section, the global
+ // could be densely packed with other objects in the section, and
+ // increasing the alignment could cause padding issues.)
+ if (hasSection() && getAlignment() > 0)
+ return false;
+
+ // On ELF platforms, we're further restricted in that we can't
+ // increase the alignment of any variable which might be emitted
+ // into a shared library, and which is exported. If the main
+ // executable accesses a variable found in a shared-lib, the main
+ // exe actually allocates memory for and exports the symbol ITSELF,
+ // overriding the symbol found in the library. That is, at link
+ // time, the observed alignment of the variable is copied into the
+ // executable binary. (A COPY relocation is also generated, to copy
+ // the initial data from the shadowed variable in the shared-lib
+ // into the location in the main binary, before running code.)
+ //
+ // And thus, even though you might think you are defining the
+ // global, and allocating the memory for the global in your object
+ // file, and thus should be able to set the alignment arbitrarily,
+ // that's not actually true. Doing so can cause an ABI breakage; an
+ // executable might have already been built with the previous
+ // alignment of the variable, and then assuming an increased
+ // alignment will be incorrect.
+
+ // Conservatively assume ELF if there's no parent pointer.
+ bool isELF =
+ (!Parent || Triple(Parent->getTargetTriple()).isOSBinFormatELF());
+ if (isELF && hasDefaultVisibility() && !hasLocalLinkage())
+ return false;
+
+ return true;
+}
+
//===----------------------------------------------------------------------===//
// GlobalVariable Implementation
//===----------------------------------------------------------------------===//
Constant *InitVal, const Twine &Name,
ThreadLocalMode TLMode, unsigned AddressSpace,
bool isExternallyInitialized)
- : GlobalObject(PointerType::get(Ty, AddressSpace), Value::GlobalVariableVal,
+ : GlobalObject(Ty, Value::GlobalVariableVal,
OperandTraits<GlobalVariable>::op_begin(this),
- InitVal != nullptr, Link, Name),
+ InitVal != nullptr, Link, Name, AddressSpace),
isConstantGlobal(constant),
isExternallyInitializedConstant(isExternallyInitialized) {
setThreadLocalMode(TLMode);
const Twine &Name, GlobalVariable *Before,
ThreadLocalMode TLMode, unsigned AddressSpace,
bool isExternallyInitialized)
- : GlobalObject(PointerType::get(Ty, AddressSpace), Value::GlobalVariableVal,
+ : GlobalObject(Ty, Value::GlobalVariableVal,
OperandTraits<GlobalVariable>::op_begin(this),
- InitVal != nullptr, Link, Name),
+ InitVal != nullptr, Link, Name, AddressSpace),
isConstantGlobal(constant),
isExternallyInitializedConstant(isExternallyInitialized) {
setThreadLocalMode(TLMode);
}
if (Before)
- Before->getParent()->getGlobalList().insert(Before, this);
+ Before->getParent()->getGlobalList().insert(Before->getIterator(), this);
else
M.getGlobalList().push_back(this);
}
}
void GlobalVariable::removeFromParent() {
- getParent()->getGlobalList().remove(this);
+ getParent()->getGlobalList().remove(getIterator());
}
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));
+ getParent()->getGlobalList().erase(getIterator());
}
void GlobalVariable::setInitializer(Constant *InitVal) {
}
}
-/// copyAttributesFrom - copy all additional attributes (those not needed to
-/// create a GlobalVariable) from the GlobalVariable Src to this one.
+/// 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!");
GlobalObject::copyAttributesFrom(Src);
- const GlobalVariable *SrcVar = cast<GlobalVariable>(Src);
- setThreadLocalMode(SrcVar->getThreadLocalMode());
- setExternallyInitialized(SrcVar->isExternallyInitialized());
+ if (const GlobalVariable *SrcVar = dyn_cast<GlobalVariable>(Src)) {
+ setThreadLocalMode(SrcVar->getThreadLocalMode());
+ setExternallyInitialized(SrcVar->isExternallyInitialized());
+ }
}
// GlobalAlias Implementation
//===----------------------------------------------------------------------===//
-GlobalAlias::GlobalAlias(PointerType *Ty, LinkageTypes Link, const Twine &Name,
- Constant *Aliasee, Module *ParentModule)
- : GlobalValue(Ty, Value::GlobalAliasVal, &Op<0>(), 1, Link, Name) {
+GlobalAlias::GlobalAlias(Type *Ty, unsigned AddressSpace, LinkageTypes Link,
+ const Twine &Name, Constant *Aliasee,
+ Module *ParentModule)
+ : GlobalValue(Ty, Value::GlobalAliasVal, &Op<0>(), 1, Link, Name,
+ AddressSpace) {
Op<0>() = Aliasee;
if (ParentModule)
ParentModule->getAliasList().push_back(this);
}
-GlobalAlias *GlobalAlias::create(PointerType *Ty, LinkageTypes Link,
- const Twine &Name, Constant *Aliasee,
- Module *ParentModule) {
- return new GlobalAlias(Ty, Link, Name, Aliasee, ParentModule);
+GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace,
+ LinkageTypes Link, const Twine &Name,
+ Constant *Aliasee, Module *ParentModule) {
+ return new GlobalAlias(Ty, AddressSpace, Link, Name, Aliasee, ParentModule);
}
-GlobalAlias *GlobalAlias::create(PointerType *Ty, LinkageTypes Linkage,
- const Twine &Name, Module *Parent) {
- return create(Ty, Linkage, Name, nullptr, Parent);
+GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace,
+ LinkageTypes Linkage, const Twine &Name,
+ Module *Parent) {
+ return create(Ty, AddressSpace, Linkage, Name, nullptr, Parent);
}
-GlobalAlias *GlobalAlias::create(PointerType *Ty, LinkageTypes Linkage,
- const Twine &Name, GlobalValue *Aliasee) {
- return create(Ty, Linkage, Name, Aliasee, Aliasee->getParent());
+GlobalAlias *GlobalAlias::create(Type *Ty, unsigned AddressSpace,
+ LinkageTypes Linkage, const Twine &Name,
+ GlobalValue *Aliasee) {
+ return create(Ty, AddressSpace, Linkage, Name, Aliasee, Aliasee->getParent());
}
GlobalAlias *GlobalAlias::create(LinkageTypes Link, const Twine &Name,
GlobalValue *Aliasee) {
PointerType *PTy = Aliasee->getType();
- return create(PTy, Link, Name, Aliasee);
+ return create(PTy->getElementType(), PTy->getAddressSpace(), Link, Name,
+ Aliasee);
}
GlobalAlias *GlobalAlias::create(const Twine &Name, GlobalValue *Aliasee) {
}
void GlobalAlias::removeFromParent() {
- getParent()->getAliasList().remove(this);
+ getParent()->getAliasList().remove(getIterator());
}
void GlobalAlias::eraseFromParent() {
- getParent()->getAliasList().erase(this);
+ getParent()->getAliasList().erase(getIterator());
}
void GlobalAlias::setAliasee(Constant *Aliasee) {
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