void rewriteFunctionType(IrFuncTy &fty) override {
const bool externD = (fty.type->linkage == LINKd &&
fty.type->parameterList.varargs != VARARGvariadic);
// return value:
if (!fty.ret->byref) {
Type *rt = fty.type->next->toBasetype(); // for sret, rt == void
if (isAggregate(rt) && !isMagicCppStruct(rt) && canRewriteAsInt(rt) &&
// don't rewrite cfloat for extern(D)
!(externD && rt->ty == Tcomplex32)) {
integerRewrite.applyToIfNotObsolete(*fty.ret);
}
}
// extern(D): try passing an argument in EAX
if (externD) {
// try an implicit argument...
if (fty.arg_this) {
Logger::println("Putting 'this' in register");
fty.arg_this->attrs.addAttribute(LLAttribute::InReg);
} else if (fty.arg_nest) {
Logger::println("Putting context ptr in register");
fty.arg_nest->attrs.addAttribute(LLAttribute::InReg);
} else if (IrFuncTyArg *sret = fty.arg_sret) {
Logger::println("Putting sret ptr in register");
// sret and inreg are incompatible, but the ABI requires the
// sret parameter to be in EAX in this situation...
sret->attrs.removeAttribute(LLAttribute::StructRet);
sret->attrs.addAttribute(LLAttribute::InReg);
}
// ... otherwise try the last argument
else if (!fty.args.empty()) {
// The last parameter is passed in EAX rather than being pushed on the
// stack if the following conditions are met:
// * It fits in EAX.
// * It is not a 3 byte struct.
// * It is not a floating point type.
IrFuncTyArg *last = fty.args.back();
Type *lastTy = last->type->toBasetype();
unsigned sz = lastTy->size();
if (last->byref && !last->isByVal()) {
Logger::println("Putting last (byref) parameter in register");
last->attrs.addAttribute(LLAttribute::InReg);
} else if (!lastTy->isfloating() && (sz == 1 || sz == 2 || sz == 4)) {
// rewrite aggregates as integers to make inreg work
if (lastTy->ty == Tstruct || lastTy->ty == Tsarray) {
integerRewrite.applyTo(*last);
// undo byval semantics applied via passByVal() returning true
last->byref = false;
last->attrs.clear();
}
last->attrs.addAttribute(LLAttribute::InReg);
}
}
// all other arguments are passed on the stack, don't rewrite
}
// extern(C++) on Posix: non-POD args are passed indirectly by-value
else if (!isMSVC && fty.type->linkage == LINKcpp) {
for (auto arg : fty.args) {
if (!arg->byref && !isPOD(arg->type))
indirectByvalRewrite.applyTo(*arg);
}
}
workaroundIssue1356(fty.args);
// Clang does not pass empty structs, while it seems that GCC does,
// at least on Linux x86. We don't know whether the C compiler will
// be Clang or GCC, so just assume Clang on OS X and G++ on Linux.
if (externD || !isOSX)
return;
size_t i = 0;
while (i < fty.args.size()) {
Type *type = fty.args[i]->type->toBasetype();
if (type->ty == Tstruct) {
// Do not pass empty structs at all for C++ ABI compatibility.
// Tests with clang reveal that more complex "empty" types, for
// example a struct containing an empty struct, are not
// optimized in the same way.
auto sd = static_cast<TypeStruct *>(type)->sym;
if (sd->fields.empty()) {
fty.args.erase(fty.args.begin() + i);
continue;
}
}
++i;
}
}
static void addExplicitArguments(std::vector<LLValue *> &args, AttrSet &attrs,
IrFuncTy &irFty, LLFunctionType *callableTy,
const std::vector<DValue *> &argvals,
int numFormalParams) {
// Number of arguments added to the LLVM type that are implicit on the
// frontend side of things (this, context pointers, etc.)
const size_t implicitLLArgCount = args.size();
// Number of formal arguments in the LLVM type (i.e. excluding varargs).
const size_t formalLLArgCount = irFty.args.size();
// The number of explicit arguments in the D call expression (including
// varargs), not all of which necessarily generate a LLVM argument.
const size_t explicitDArgCount = argvals.size();
// construct and initialize an IrFuncTyArg object for each vararg
std::vector<IrFuncTyArg *> optionalIrArgs;
for (size_t i = numFormalParams; i < explicitDArgCount; i++) {
Type *argType = argvals[i]->getType();
bool passByVal = gABI->passByVal(argType);
AttrBuilder initialAttrs;
if (passByVal) {
initialAttrs.add(LLAttribute::ByVal);
} else {
initialAttrs.add(DtoShouldExtend(argType));
}
optionalIrArgs.push_back(new IrFuncTyArg(argType, passByVal, initialAttrs));
optionalIrArgs.back()->parametersIdx = i;
}
// let the ABI rewrite the IrFuncTyArg objects
gABI->rewriteVarargs(irFty, optionalIrArgs);
const size_t explicitLLArgCount = formalLLArgCount + optionalIrArgs.size();
args.resize(implicitLLArgCount + explicitLLArgCount,
static_cast<llvm::Value *>(nullptr));
// Iterate the explicit arguments from left to right in the D source,
// which is the reverse of the LLVM order if irFty.reverseParams is true.
for (size_t i = 0; i < explicitLLArgCount; ++i) {
const bool isVararg = (i >= irFty.args.size());
IrFuncTyArg *irArg = nullptr;
if (isVararg) {
irArg = optionalIrArgs[i - numFormalParams];
} else {
irArg = irFty.args[i];
}
DValue *const argval = argvals[irArg->parametersIdx];
Type *const argType = argval->getType();
llvm::Value *llVal = nullptr;
if (isVararg) {
llVal = irFty.putParam(*irArg, argval);
} else {
llVal = irFty.putParam(i, argval);
}
const size_t llArgIdx =
implicitLLArgCount +
(irFty.reverseParams ? explicitLLArgCount - i - 1 : i);
llvm::Type *const callableArgType =
(isVararg ? nullptr : callableTy->getParamType(llArgIdx));
// Hack around LDC assuming structs and static arrays are in memory:
// If the function wants a struct, and the argument value is a
// pointer to a struct, load from it before passing it in.
if (isaPointer(llVal) && DtoIsPassedByRef(argType) &&
((!isVararg && !isaPointer(callableArgType)) ||
(isVararg && !irArg->byref && !irArg->isByVal()))) {
Logger::println("Loading struct type for function argument");
llVal = DtoLoad(llVal);
}
// parameter type mismatch, this is hard to get rid of
if (!isVararg && llVal->getType() != callableArgType) {
IF_LOG {
Logger::cout() << "arg: " << *llVal << '\n';
Logger::cout() << "expects: " << *callableArgType << '\n';
}
if (isaStruct(llVal)) {
llVal = DtoAggrPaint(llVal, callableArgType);
} else {
llVal = DtoBitCast(llVal, callableArgType);
}
}
args[llArgIdx] = llVal;
// +1 as index 0 contains the function attributes.
attrs.add(llArgIdx + 1, irArg->attrs);
if (isVararg) {
delete irArg;
}
}
void rewriteFunctionType(TypeFunction* tf, IrFuncTy &fty)
{
// extern(D)
if (tf->linkage == LINKd)
{
// IMPLICIT PARAMETERS
// mark this/nested params inreg
if (fty.arg_this)
{
Logger::println("Putting 'this' in register");
fty.arg_this->attrs.clear()
.add(LDC_ATTRIBUTE(InReg));
}
else if (fty.arg_nest)
{
Logger::println("Putting context ptr in register");
fty.arg_nest->attrs.clear()
.add(LDC_ATTRIBUTE(InReg));
}
else if (IrFuncTyArg* sret = fty.arg_sret)
{
Logger::println("Putting sret ptr in register");
// sret and inreg are incompatible, but the ABI requires the
// sret parameter to be in EAX in this situation...
sret->attrs.add(LDC_ATTRIBUTE(InReg)).remove(LDC_ATTRIBUTE(StructRet));
}
// otherwise try to mark the last param inreg
else if (!fty.args.empty())
{
// The last parameter is passed in EAX rather than being pushed on the stack if the following conditions are met:
// * It fits in EAX.
// * It is not a 3 byte struct.
// * It is not a floating point type.
IrFuncTyArg* last = fty.args.back();
Type* lastTy = last->type->toBasetype();
unsigned sz = lastTy->size();
if (last->byref && !last->isByVal())
{
Logger::println("Putting last (byref) parameter in register");
last->attrs.add(LDC_ATTRIBUTE(InReg));
}
else if (!lastTy->isfloating() && (sz == 1 || sz == 2 || sz == 4)) // right?
{
// rewrite the struct into an integer to make inreg work
if (lastTy->ty == Tstruct || lastTy->ty == Tsarray)
{
last->rewrite = &integerRewrite;
last->ltype = integerRewrite.type(last->type, last->ltype);
last->byref = false;
// erase previous attributes
last->attrs.clear();
}
last->attrs.add(LDC_ATTRIBUTE(InReg));
}
}
// FIXME: tf->varargs == 1 need to use C calling convention and vararg mechanism to live up to the spec:
// "The caller is expected to clean the stack. _argptr is not passed, it is computed by the callee."
// EXPLICIT PARAMETERS
// reverse parameter order
// for non variadics
if (!fty.args.empty() && tf->varargs != 1)
{
fty.reverseParams = true;
}
}
// extern(C) and all others
else
{
// RETURN VALUE
// cfloat -> i64
if (tf->next->toBasetype() == Type::tcomplex32)
{
fty.ret->rewrite = &integerRewrite;
fty.ret->ltype = integerRewrite.type(fty.ret->type, fty.ret->ltype);
}
// IMPLICIT PARAMETERS
// EXPLICIT PARAMETERS
}
}
void rewriteFunctionType(TypeFunction* tf)
{
IrFuncTy& fty = tf->fty;
Type* rt = fty.ret->type->toBasetype();
// extern(D)
if (tf->linkage == LINKd)
{
// RETURN VALUE
// complex {re,im} -> {im,re}
if (rt->iscomplex())
{
Logger::println("Rewriting complex return value");
fty.ret->rewrite = &swapComplex;
}
// IMPLICIT PARAMETERS
// mark this/nested params inreg
if (fty.arg_this)
{
Logger::println("Putting 'this' in register");
#if LDC_LLVM_VER >= 302
fty.arg_this->attrs = llvm::Attributes::get(gIR->context(), llvm::AttrBuilder().addAttribute(llvm::Attributes::InReg));
#else
fty.arg_this->attrs = llvm::Attribute::InReg;
#endif
}
else if (fty.arg_nest)
{
Logger::println("Putting context ptr in register");
#if LDC_LLVM_VER >= 302
fty.arg_nest->attrs = llvm::Attributes::get(gIR->context(), llvm::AttrBuilder().addAttribute(llvm::Attributes::InReg));
#else
fty.arg_nest->attrs = llvm::Attribute::InReg;
#endif
}
else if (IrFuncTyArg* sret = fty.arg_sret)
{
Logger::println("Putting sret ptr in register");
// sret and inreg are incompatible, but the ABI requires the
// sret parameter to be in EAX in this situation...
#if LDC_LLVM_VER >= 302
sret->attrs = llvm::Attributes::get(gIR->context(), llvm::AttrBuilder(sret->attrs).addAttribute(llvm::Attributes::InReg)
.removeAttribute(llvm::Attributes::StructRet));
#else
sret->attrs = (sret->attrs | llvm::Attribute::InReg)
& ~llvm::Attribute::StructRet;
#endif
}
// otherwise try to mark the last param inreg
else if (!fty.args.empty())
{
// The last parameter is passed in EAX rather than being pushed on the stack if the following conditions are met:
// * It fits in EAX.
// * It is not a 3 byte struct.
// * It is not a floating point type.
IrFuncTyArg* last = fty.args.back();
Type* lastTy = last->type->toBasetype();
unsigned sz = lastTy->size();
if (last->byref && !last->isByVal())
{
Logger::println("Putting last (byref) parameter in register");
#if LDC_LLVM_VER >= 302
last->attrs = llvm::Attributes::get(gIR->context(), llvm::AttrBuilder(last->attrs).addAttribute(llvm::Attributes::InReg));
#else
last->attrs |= llvm::Attribute::InReg;
#endif
}
else if (!lastTy->isfloating() && (sz == 1 || sz == 2 || sz == 4)) // right?
{
// rewrite the struct into an integer to make inreg work
if (lastTy->ty == Tstruct || lastTy->ty == Tsarray)
{
last->rewrite = &compositeToInt;
last->ltype = compositeToInt.type(last->type, last->ltype);
last->byref = false;
// erase previous attributes
#if LDC_LLVM_VER >= 302
last->attrs = llvm::Attributes();
#else
last->attrs = llvm::Attribute::None;
#endif
}
#if LDC_LLVM_VER >= 302
last->attrs = llvm::Attributes::get(gIR->context(), llvm::AttrBuilder(last->attrs).addAttribute(llvm::Attributes::InReg));
#else
last->attrs |= llvm::Attribute::InReg;
#endif
}
}
// FIXME: tf->varargs == 1 need to use C calling convention and vararg mechanism to live up to the spec:
// "The caller is expected to clean the stack. _argptr is not passed, it is computed by the callee."
// EXPLICIT PARAMETERS
// reverse parameter order
// for non variadics
if (!fty.args.empty() && tf->varargs != 1)
{
fty.reverseParams = true;
}
}
// extern(C) and all others
else
{
// RETURN VALUE
// cfloat -> i64
if (tf->next->toBasetype() == Type::tcomplex32)
{
fty.ret->rewrite = &cfloatToInt;
fty.ret->ltype = LLType::getInt64Ty(gIR->context());
}
// IMPLICIT PARAMETERS
// EXPLICIT PARAMETERS
}
}
