llvm::GlobalValue::LinkageTypes DtoExternalLinkage(Dsymbol* sym)
{
if (needsTemplateLinkage(sym))
return templateLinkage;
else if (isAvailableExternally(sym) && mustDefineSymbol(sym))
return llvm::GlobalValue::AvailableExternallyLinkage;
else
return llvm::GlobalValue::ExternalLinkage;
}
void DtoResolveStruct(StructDeclaration* sd)
{
// Make sure to resolve each struct type exactly once.
if (sd->ir.resolved) return;
sd->ir.resolved = true;
Logger::println("Resolving struct type: %s (%s)", sd->toChars(), sd->loc.toChars());
LOG_SCOPE;
// make sure type exists
DtoType(sd->type);
// if it's a forward declaration, all bets are off. The type should be enough
if (sd->sizeok != 1)
return;
// create the IrAggr
IrAggr* irstruct = new IrAggr(sd);
sd->ir.irStruct = irstruct;
// Set up our field metadata.
for (ArrayIter<VarDeclaration> it(sd->fields); !it.done(); it.next())
{
VarDeclaration* vd = it.get();
assert(!vd->ir.irField);
(void)new IrField(vd);
}
// perform definition
bool emitGlobalData = mustDefineSymbol(sd);
if (emitGlobalData)
{
// emit the initZ symbol
LLGlobalVariable* initZ = irstruct->getInitSymbol();
// set initZ initializer
initZ->setInitializer(irstruct->getDefaultInit());
}
// emit members
if (sd->members)
{
for (ArrayIter<Dsymbol> it(sd->members); !it.done(); it.next())
{
it.get()->codegen(Type::sir);
}
}
if (emitGlobalData)
{
// emit typeinfo
DtoTypeInfoOf(sd->type);
}
}
void VarDeclaration::codegen(Ir* p)
{
Logger::print("VarDeclaration::codegen(): %s | %s\n", toChars(), type->toChars());
LOG_SCOPE;
if (type->ty == Terror)
{ error("had semantic errors when compiling");
return;
}
// just forward aliases
if (aliassym)
{
Logger::println("alias sym");
toAlias()->codegen(p);
return;
}
// output the parent aggregate first
if (AggregateDeclaration* ad = isMember())
ad->codegen(p);
// global variable
// taken from dmd2/structs
if (isDataseg() || (storage_class & (STCconst | STCimmutable) && init))
{
Logger::println("data segment");
#if 0 // TODO:
assert(!(storage_class & STCmanifest) &&
"manifest constant being codegen'd!");
#endif
// don't duplicate work
if (this->ir.resolved) return;
this->ir.resolved = true;
this->ir.declared = true;
this->ir.irGlobal = new IrGlobal(this);
Logger::println("parent: %s (%s)", parent->toChars(), parent->kind());
// not sure why this is only needed for d2
bool _isconst = isConst() && init;
Logger::println("Creating global variable");
assert(!ir.initialized);
ir.initialized = gIR->dmodule;
std::string _name(mangle());
LLType *_type = DtoConstInitializerType(type, init);
// create the global variable
#if LDC_LLVM_VER >= 302
// FIXME: clang uses a command line option for the thread model
LLGlobalVariable* gvar = new LLGlobalVariable(*gIR->module, _type, _isconst,
DtoLinkage(this), NULL, _name, 0,
isThreadlocal() ? LLGlobalVariable::GeneralDynamicTLSModel
: LLGlobalVariable::NotThreadLocal);
#else
LLGlobalVariable* gvar = new LLGlobalVariable(*gIR->module, _type, _isconst,
DtoLinkage(this), NULL, _name, 0, isThreadlocal());
#endif
this->ir.irGlobal->value = gvar;
// Set the alignment (it is important not to use type->alignsize because
// VarDeclarations can have an align() attribute independent of the type
// as well).
if (alignment != STRUCTALIGN_DEFAULT)
gvar->setAlignment(alignment);
if (Logger::enabled())
Logger::cout() << *gvar << '\n';
// if this global is used from a nested function, this is necessary or
// optimization could potentially remove the global (if it's the only use)
if (nakedUse)
gIR->usedArray.push_back(DtoBitCast(gvar, getVoidPtrType()));
// assign the initializer
if (!(storage_class & STCextern) && mustDefineSymbol(this))
{
if (Logger::enabled())
{
Logger::println("setting initializer");
Logger::cout() << "global: " << *gvar << '\n';
#if 0
Logger::cout() << "init: " << *initVal << '\n';
#endif
}
// build the initializer
LLConstant *initVal = DtoConstInitializer(loc, type, init);
// set the initializer
assert(!ir.irGlobal->constInit);
ir.irGlobal->constInit = initVal;
gvar->setInitializer(initVal);
// do debug info
DtoDwarfGlobalVariable(gvar, this);
}
}
}
void DtoResolveStruct(StructDeclaration* sd)
{
// don't do anything if already been here
if (sd->ir.resolved) return;
// make sure above works :P
sd->ir.resolved = true;
// log what we're doing
Logger::println("Resolving struct type: %s (%s)", sd->toChars(), sd->loc.toChars());
LOG_SCOPE;
// make sure type exists
DtoType(sd->type);
// if it's a forward declaration, all bets are off. The type should be enough
if (sd->sizeok != 1)
return;
// create the IrStruct
IrStruct* irstruct = new IrStruct(sd);
sd->ir.irStruct = irstruct;
// make sure all fields really get their ir field
ArrayIter<VarDeclaration> it(sd->fields);
for (; !it.done(); it.next())
{
VarDeclaration* vd = it.get();
if (vd->ir.irField == NULL) {
new IrField(vd);
} else {
IF_LOG Logger::println("struct field already exists!!!");
}
}
// perform definition
bool needs_def = mustDefineSymbol(sd);
if (needs_def)
{
// emit the initZ symbol
LLGlobalVariable* initZ = irstruct->getInitSymbol();
// set initZ initializer
initZ->setInitializer(irstruct->getDefaultInit());
}
// emit members
if (sd->members)
{
ArrayIter<Dsymbol> it(*sd->members);
while (!it.done())
{
Dsymbol* member = it.get();
if (member)
member->codegen(Type::sir);
it.next();
}
}
if (needs_def)
{
// emit typeinfo
DtoTypeInfoOf(sd->type);
}
}
void DtoResolveClass(ClassDeclaration* cd)
{
// make sure the base classes are processed first
ArrayIter<BaseClass> base_iter(cd->baseclasses);
while (base_iter.more())
{
BaseClass* bc = base_iter.get();
if (bc)
{
bc->base->codegen(Type::sir);
}
base_iter.next();
}
if (cd->ir.resolved) return;
cd->ir.resolved = true;
Logger::println("DtoResolveClass(%s): %s", cd->toPrettyChars(), cd->loc.toChars());
LOG_SCOPE;
// make sure type exists
DtoType(cd->type);
// create IrStruct
assert(cd->ir.irStruct == NULL);
IrStruct* irstruct = new IrStruct(cd);
cd->ir.irStruct = irstruct;
// make sure all fields really get their ir field
ArrayIter<VarDeclaration> it(cd->fields);
for (; !it.done(); it.next())
{
VarDeclaration* vd = it.get();
if (vd->ir.irField == NULL) {
new IrField(vd);
} else {
IF_LOG Logger::println("class field already exists!!!");
}
}
bool needs_def = mustDefineSymbol(cd);
// emit the ClassZ symbol
LLGlobalVariable* ClassZ = irstruct->getClassInfoSymbol();
// emit the interfaceInfosZ symbol if necessary
if (cd->vtblInterfaces && cd->vtblInterfaces->dim > 0)
irstruct->getInterfaceArraySymbol(); // initializer is applied when it's built
// interface only emit typeinfo and classinfo
if (cd->isInterfaceDeclaration())
{
irstruct->initializeInterface();
}
else
{
// emit the initZ symbol
LLGlobalVariable* initZ = irstruct->getInitSymbol();
// emit the vtblZ symbol
LLGlobalVariable* vtblZ = irstruct->getVtblSymbol();
// perform definition
if (needs_def)
{
// set symbol initializers
initZ->setInitializer(irstruct->getDefaultInit());
vtblZ->setInitializer(irstruct->getVtblInit());
}
}
// emit members
if (cd->members)
{
ArrayIter<Dsymbol> it(*cd->members);
while (!it.done())
{
Dsymbol* member = it.get();
if (member)
member->codegen(Type::sir);
it.next();
}
}
if (needs_def)
{
// emit typeinfo
DtoTypeInfoOf(cd->type);
// define classinfo
ClassZ->setInitializer(irstruct->getClassInfoInit());
}
}
void VarDeclaration::codegen(Ir* p)
{
Logger::print("VarDeclaration::codegen(): %s | %s\n", toChars(), type->toChars());
LOG_SCOPE;
if (type->ty == Terror)
{ error("had semantic errors when compiling");
return;
}
// just forward aliases
if (aliassym)
{
Logger::println("alias sym");
toAlias()->codegen(p);
return;
}
// output the parent aggregate first
if (AggregateDeclaration* ad = isMember())
ad->codegen(p);
// global variable
if (isDataseg() || (storage_class & (STCconst | STCimmutable) && init))
{
Logger::println("data segment");
#if 0 // TODO:
assert(!(storage_class & STCmanifest) &&
"manifest constant being codegen'd!");
#endif
// don't duplicate work
if (this->ir.resolved) return;
this->ir.resolved = true;
this->ir.declared = true;
this->ir.irGlobal = new IrGlobal(this);
Logger::println("parent: %s (%s)", parent->toChars(), parent->kind());
const bool isLLConst = isConst() && init;
const llvm::GlobalValue::LinkageTypes llLinkage = DtoLinkage(this);
assert(!ir.initialized);
ir.initialized = gIR->dmodule;
std::string llName(mangle());
// Since the type of a global must exactly match the type of its
// initializer, we cannot know the type until after we have emitted the
// latter (e.g. in case of unions, …). However, it is legal for the
// initializer to refer to the address of the variable. Thus, we first
// create a global with the generic type (note the assignment to
// this->ir.irGlobal->value!), and in case we also do an initializer
// with a different type later, swap it out and replace any existing
// uses with bitcasts to the previous type.
llvm::GlobalVariable* gvar = getOrCreateGlobal(loc, *gIR->module,
i1ToI8(DtoType(type)), isLLConst, llLinkage, 0, llName,
isThreadlocal());
this->ir.irGlobal->value = gvar;
// Check if we are defining or just declaring the global in this module.
if (!(storage_class & STCextern) && mustDefineSymbol(this))
{
// Build the initializer. Might use this->ir.irGlobal->value!
LLConstant *initVal = DtoConstInitializer(loc, type, init);
// In case of type mismatch, swap out the variable.
if (initVal->getType() != gvar->getType()->getElementType())
{
llvm::GlobalVariable* newGvar = getOrCreateGlobal(loc,
*gIR->module, initVal->getType(), isLLConst, llLinkage, 0,
"", // We take on the name of the old global below.
isThreadlocal());
newGvar->takeName(gvar);
llvm::Constant* newValue =
llvm::ConstantExpr::getBitCast(newGvar, gvar->getType());
gvar->replaceAllUsesWith(newValue);
gvar->eraseFromParent();
gvar = newGvar;
this->ir.irGlobal->value = newGvar;
}
// Now, set the initializer.
assert(!ir.irGlobal->constInit);
ir.irGlobal->constInit = initVal;
gvar->setInitializer(initVal);
// Also set up the edbug info.
DtoDwarfGlobalVariable(gvar, this);
}
// Set the alignment (it is important not to use type->alignsize because
// VarDeclarations can have an align() attribute independent of the type
// as well).
if (alignment != STRUCTALIGN_DEFAULT)
gvar->setAlignment(alignment);
// If this global is used from a naked function, we need to create an
// artificial "use" for it, or it could be removed by the optimizer if
// the only reference to it is in inline asm.
if (nakedUse)
gIR->usedArray.push_back(DtoBitCast(gvar, getVoidPtrType()));
if (Logger::enabled())
Logger::cout() << *gvar << '\n';
}
}
LLGlobalValue::LinkageTypes DtoLinkage(Dsymbol* sym)
{
const bool mustDefine = mustDefineSymbol(sym);
// global/static variable
if (VarDeclaration* vd = sym->isVarDeclaration())
{
if (mustDefine)
{
IF_LOG Logger::println("Variable %savailable externally: %s",
(vd->availableExternally ? "" : "not "), vd->toChars());
}
// generated by inlining semantics run
if (vd->availableExternally && mustDefine)
return llvm::GlobalValue::AvailableExternallyLinkage;
// template
if (needsTemplateLinkage(sym))
return templateLinkage;
// Currently, we have to consider all variables, even function-local
// statics, to be external, as CTFE might cause template functions
// instances to be semantic3'd that occur within the body of a function
// from an imported module. Consequently, a copy of them is codegen'd
// in the importing module, even if they might reference a static in a
// function in the imported module (e.g. via an alias parameter).
//
// A fix for this would be to track instantiations/semantic3 runs made
// solely for CTFE purposes in a way similar to how the extra inlining
// semantic runs are handled.
//
// LDC_FIXME: Can this also occur for functions? Find a better solution.
if (true || vd->storage_class & STCextern)
return llvm::GlobalValue::ExternalLinkage;
}
else if (FuncDeclaration* fdecl = sym->isFuncDeclaration())
{
if (mustDefine)
{
IF_LOG Logger::println("Function %savailable externally: %s",
(fdecl->availableExternally ? "" : "not "), fdecl->toChars());
}
assert(fdecl->type->ty == Tfunction);
TypeFunction* ft = static_cast<TypeFunction*>(fdecl->type);
// intrinsics are always external
if (fdecl->llvmInternal == LLVMintrinsic)
return llvm::GlobalValue::ExternalLinkage;
// Mark functions generated by an inlining semantic run as
// available_externally. Naked functions are turned into module-level
// inline asm and are thus declaration-only as far as the LLVM IR level
// is concerned.
if (fdecl->availableExternally && mustDefine && !fdecl->naked)
return llvm::GlobalValue::AvailableExternallyLinkage;
// array operations are always template linkage
if (fdecl->isArrayOp == 1)
return templateLinkage;
// template instances should have weak linkage
// but only if there's a body, and it's not naked
// otherwise we make it external
if (needsTemplateLinkage(fdecl) && fdecl->fbody && !fdecl->naked)
return templateLinkage;
// extern(C) functions are always external
if (ft->linkage == LINKc)
return llvm::GlobalValue::ExternalLinkage;
// If a function without a body is nested in another
// function, we cannot use internal linkage for that
// function (see below about nested functions)
// FIXME: maybe there is a better way without emission
// of needless symbols?
if (!fdecl->fbody)
return llvm::GlobalValue::ExternalLinkage;
}
// class
else if (ClassDeclaration* cd = sym->isClassDeclaration())
{
if (mustDefine)
{
IF_LOG Logger::println("Class %savailable externally: %s",
(cd->availableExternally ? "" : "not "), vd->toChars());
}
// generated by inlining semantics run
if (cd->availableExternally && mustDefine)
return llvm::GlobalValue::AvailableExternallyLinkage;
// template
if (needsTemplateLinkage(cd))
return templateLinkage;
}
else
{
llvm_unreachable("not global/function");
}
// If the function needs to be defined in the current module, check if it
// is a nested function and we can declare it as internal.
bool canInternalize = mustDefine;
// Nested naked functions and the implicitly generated __require/__ensure
// functions for in/out contracts cannot be internalized. The reason
// for the latter is that contract functions, despite being nested, can be
// referenced from other D modules e.g. in the case of contracts on
// interface methods (where __require/__ensure are emitted to the module
// where the interface is declared, but an actual interface implementation
// can be in a completely different place).
if (canInternalize)
{
if (FuncDeclaration* fd = sym->isFuncDeclaration())
{
if ((fd->naked != 0) ||
(fd->ident == Id::require) || (fd->ident == Id::ensure))
{
canInternalize = false;
}
}
}
// Any symbol nested in a function that cannot be inlined can't be
// referenced directly from outside that function, so we can give
// such symbols internal linkage. This holds even if nested indirectly,
// such as member functions of aggregates nested in functions.
//
// Note: This must be checked after things like template member-ness or
// symbols nested in templates would get duplicated for each module,
// breaking things like
// ---
// int counter(T)() { static int i; return i++; }"
// ---
// if instances get emitted in multiple object files because they'd use
// different instances of 'i'.
// TODO: Check if we are giving away too much inlining potential due to
// canInline being overly conservative here.
if (canInternalize)
{
for (Dsymbol* parent = sym->parent; parent ; parent = parent->parent)
{
FuncDeclaration *fd = parent->isFuncDeclaration();
if (fd && !fd->canInline(fd->needThis(), false, false))
{
// We also cannot internalize nested functions which are
// leaked to the outside via a templated return type, because
// that type will also be codegen'd in any caller modules (see
// GitHub issue #131).
// Since we can't easily determine if this is really the case
// here, just don't internalize it if the parent returns a
// template at all, to be safe.
TypeFunction* tf = static_cast<TypeFunction*>(fd->type);
if (!DtoIsTemplateInstance(tf->next->toDsymbol(fd->scope)))
return llvm::GlobalValue::InternalLinkage;
}
}
}
// default to external linkage
return llvm::GlobalValue::ExternalLinkage;
}