void rewriteArgument(IrFuncTy& fty, IrFuncTyArg& arg)
{
Type* ty = arg.type->toBasetype();
if (ty->ty == Tstruct || ty->ty == Tsarray)
{
if (canRewriteAsInt(ty))
{
arg.rewrite = &integerRewrite;
arg.ltype = integerRewrite.type(arg.type, arg.ltype);
}
else
{
// these types are passed byval:
// the caller allocates a copy and then passes a pointer to the copy
arg.rewrite = &byvalRewrite;
arg.ltype = byvalRewrite.type(arg.type, arg.ltype);
// the copy is treated as a local variable of the callee
// hence add the NoAlias and NoCapture attributes
arg.attrs.clear()
.add(LDC_ATTRIBUTE(NoAlias))
.add(LDC_ATTRIBUTE(NoCapture));
}
}
}
void Win64TargetABI::rewriteArgument(IrFuncTy& fty, IrFuncTyArg& arg)
{
LLType* originalLType = arg.ltype;
Type* t = arg.type->toBasetype();
if (isPassedWithByvalSemantics(t))
{
// these types are passed byval:
// the caller allocates a copy and then passes a pointer to the copy
arg.rewrite = &byvalRewrite;
arg.ltype = byvalRewrite.type(arg.type, arg.ltype);
// the copy is treated as a local variable of the callee
// hence add the NoAlias and NoCapture attributes
arg.attrs.clear()
.add(LDC_ATTRIBUTE(NoAlias))
.add(LDC_ATTRIBUTE(NoCapture));
}
else if (isAggregate(t) && canRewriteAsInt(t) && !IntegerRewrite::isObsoleteFor(originalLType))
{
arg.rewrite = &integerRewrite;
arg.ltype = integerRewrite.type(arg.type, arg.ltype);
}
IF_LOG if (arg.rewrite)
{
Logger::println("Rewriting argument type %s", t->toChars());
LOG_SCOPE;
Logger::cout() << *originalLType << " => " << *arg.ltype << '\n';
}
}
void rewriteFunctionType(TypeFunction *tf, IrFuncTy &fty) override {
Type *retTy = fty.ret->type->toBasetype();
if (!fty.ret->byref && retTy->ty == Tstruct) {
// Rewrite HFAs only because union HFAs are turned into IR types that are
// non-HFA and messes up register selection
if (isHFA((TypeStruct *)retTy, &fty.ret->ltype)) {
fty.ret->rewrite = &hfaToArray;
fty.ret->ltype = hfaToArray.type(fty.ret->type);
}
else {
fty.ret->rewrite = &integerRewrite;
fty.ret->ltype = integerRewrite.type(fty.ret->type);
}
}
for (auto arg : fty.args) {
if (!arg->byref)
rewriteArgument(fty, *arg);
}
// extern(D): reverse parameter order for non variadics, for DMD-compliance
if (tf->linkage == LINKd && tf->varargs != 1 && fty.args.size() > 1) {
fty.reverseParams = true;
}
}
void rewriteFunctionType(IrFuncTy &fty) override {
Type *retTy = fty.ret->type->toBasetype();
if (!fty.ret->byref && retTy->ty == Tstruct) {
// Rewrite HFAs only because union HFAs are turned into IR types that are
// non-HFA and messes up register selection
if (isHFA((TypeStruct *)retTy, &fty.ret->ltype)) {
hfaToArray.applyTo(*fty.ret, fty.ret->ltype);
} else {
integerRewrite.applyTo(*fty.ret);
}
}
for (auto arg : fty.args) {
if (!arg->byref)
rewriteArgument(fty, *arg);
}
}
void rewriteArgument(IrFuncTy &fty, IrFuncTyArg &arg) override {
Type *ty = arg.type->toBasetype();
if (ty->ty == Tstruct || ty->ty == Tsarray) {
if (ty->ty == Tstruct && isHFA((TypeStruct *)ty, &arg.ltype, 8)) {
arg.rewrite = &hfaToArray;
arg.ltype = hfaToArray.type(arg.type);
} else if (canRewriteAsInt(ty, true)) {
arg.rewrite = &integerRewrite;
arg.ltype = integerRewrite.type(arg.type);
} else {
arg.rewrite = &compositeToArray64;
arg.ltype = compositeToArray64.type(arg.type);
}
} else if (ty->isintegral()) {
arg.attrs.add(ty->isunsigned() ? LLAttribute::ZExt : LLAttribute::SExt);
}
}
void rewriteFunctionType(TypeFunction *tf, IrFuncTy &fty) override {
Type *retTy = fty.ret->type->toBasetype();
if (!fty.ret->byref && retTy->ty == Tstruct) {
// Rewrite HFAs only because union HFAs are turned into IR types that are
// non-HFA and messes up register selection
if (isHFA((TypeStruct *)retTy, &fty.ret->ltype)) {
fty.ret->rewrite = &hfaToArray;
fty.ret->ltype = hfaToArray.type(fty.ret->type);
}
else {
fty.ret->rewrite = &integerRewrite;
fty.ret->ltype = integerRewrite.type(fty.ret->type);
}
}
for (auto arg : fty.args) {
if (!arg->byref)
rewriteArgument(fty, *arg);
else if (passByVal(arg->type))
arg->attrs.remove(LLAttribute::ByVal);
}
}
void rewriteArgument(IrFuncTy &fty, IrFuncTyArg &arg) override {
Type *ty = arg.type->toBasetype();
if (ty->ty == Tstruct || ty->ty == Tsarray) {
if (canRewriteAsInt(ty, Is64Bit)) {
if (!IntegerRewrite::isObsoleteFor(arg.ltype)) {
arg.rewrite = &integerRewrite;
arg.ltype = integerRewrite.type(arg.type, arg.ltype);
}
} else {
// these types are passed byval:
// the caller allocates a copy and then passes a pointer to the copy
arg.rewrite = &byvalRewrite;
arg.ltype = byvalRewrite.type(arg.type, arg.ltype);
// the copy is treated as a local variable of the callee
// hence add the NoAlias and NoCapture attributes
arg.attrs.clear()
.add(LLAttribute::NoAlias)
.add(LLAttribute::NoCapture)
.addAlignment(byvalRewrite.alignment(arg.type));
}
}
}
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;
}
}
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
}
}