/**
* Output a TLS symbol for Mach-O.
*
* A TLS variable in the Mach-O format consists of two symbols.
* One symbol for the data, which contains the initializer, if any.
* The name of this symbol is the same as the variable, but with the
* "$tlv$init" suffix. If the variable has an initializer it's placed in
* the __thread_data section. Otherwise it's placed in the __thread_bss
* section.
*
* The other symbol is for the TLV descriptor. The symbol has the same
* name as the variable and is placed in the __thread_vars section.
* A TLV descriptor has the following structure, where T is the type of
* the variable:
*
* struct TLVDescriptor(T)
* {
* extern(C) T* function(TLVDescriptor*) thunk;
* size_t key;
* size_t offset;
* }
*
* Input:
* vd the variable declaration for the symbol
* s the symbol to output
*/
void tlsToDt(VarDeclaration *vd, Symbol *s, DtBuilder& dtb)
{
assert(config.objfmt == OBJ_MACH && I64 && (s->ty() & mTYLINK) == mTYthread);
Symbol *tlvInit = createTLVDataSymbol(vd, s);
DtBuilder tlvInitDtb;
if (vd->_init)
initializerToDt(vd, tlvInitDtb);
else
Type_toDt(vd->type, &tlvInitDtb);
tlvInit->Sdt = tlvInitDtb.finish();
outdata(tlvInit);
if (I64)
tlvInit->Sclass = SCextern;
Symbol* tlvBootstrap = objmod->tlv_bootstrap();
dtb.xoff(tlvBootstrap, 0, TYnptr);
dtb.size(0);
dtb.xoff(tlvInit, 0, TYnptr);
}
void visit(VarDeclaration *vd)
{
//printf("VarDeclaration::toObjFile(%p '%s' type=%s) protection %d\n", vd, vd->toChars(), vd->type->toChars(), vd->protection);
//printf("\talign = %d\n", vd->alignment);
if (vd->type->ty == Terror)
{
vd->error("had semantic errors when compiling");
return;
}
if (vd->aliassym)
{
visitNoMultiObj(vd->toAlias());
return;
}
// Do not store variables we cannot take the address of
if (!vd->canTakeAddressOf())
{
return;
}
if (!vd->isDataseg() || vd->storage_class & STCextern)
return;
Symbol *s = toSymbol(vd);
unsigned sz = vd->type->size();
Dsymbol *parent = vd->toParent();
s->Sclass = SCglobal;
do
{
/* Global template data members need to be in comdat's
* in case multiple .obj files instantiate the same
* template with the same types.
*/
if (parent->isTemplateInstance() && !parent->isTemplateMixin())
{
s->Sclass = SCcomdat;
break;
}
parent = parent->parent;
} while (parent);
s->Sfl = FLdata;
if (vd->init)
{
s->Sdt = Initializer_toDt(vd->init);
// Look for static array that is block initialized
ExpInitializer *ie = vd->init->isExpInitializer();
Type *tb = vd->type->toBasetype();
if (tb->ty == Tsarray && ie &&
!tb->nextOf()->equals(ie->exp->type->toBasetype()->nextOf()) &&
ie->exp->implicitConvTo(tb->nextOf())
)
{
size_t dim = ((TypeSArray *)tb)->dim->toInteger();
// Duplicate Sdt 'dim-1' times, as we already have the first one
dt_t **pdt = &s->Sdt;
while (--dim > 0)
{
pdt = Expression_toDt(ie->exp, pdt);
}
}
}
else
{
Type_toDt(vd->type, &s->Sdt);
}
dt_optimize(s->Sdt);
// See if we can convert a comdat to a comdef,
// which saves on exe file space.
if (s->Sclass == SCcomdat &&
s->Sdt &&
dtallzeros(s->Sdt) &&
!vd->isThreadlocal())
{
s->Sclass = SCglobal;
dt2common(&s->Sdt);
}
if (!sz && vd->type->toBasetype()->ty != Tsarray)
assert(0); // this shouldn't be possible
if (sz || objmod->allowZeroSize())
{
outdata(s);
if (vd->isExport())
objmod->export_symbol(s, 0);
}
}
void visit(VarDeclaration *vd)
{
//printf("VarDeclaration::toObjFile(%p '%s' type=%s) protection %d\n", vd, vd->toChars(), vd->type->toChars(), vd->protection);
//printf("\talign = %d\n", vd->alignment);
if (vd->type->ty == Terror)
{
vd->error("had semantic errors when compiling");
return;
}
if (vd->aliassym)
{
visitNoMultiObj(vd->toAlias());
return;
}
// Do not store variables we cannot take the address of
if (!vd->canTakeAddressOf())
{
return;
}
if (!vd->isDataseg() || vd->storage_class & STCextern)
return;
Symbol *s = toSymbol(vd);
d_uns64 sz64 = vd->type->size(vd->loc);
if (sz64 == SIZE_INVALID)
{
vd->error("size overflow");
return;
}
if (sz64 >= 0x1000000) // there has to be some 'reasonable' limit on the size
{
vd->error("size of x%llx exceeds max allowed size 0x100_0000", sz64);
}
unsigned sz = (unsigned)sz64;
Dsymbol *parent = vd->toParent();
s->Sclass = SCglobal;
do
{
/* Global template data members need to be in comdat's
* in case multiple .obj files instantiate the same
* template with the same types.
*/
if (parent->isTemplateInstance() && !parent->isTemplateMixin())
{
s->Sclass = SCcomdat;
break;
}
parent = parent->parent;
} while (parent);
s->Sfl = FLdata;
if (config.objfmt == OBJ_MACH && I64 && (s->ty() & mTYLINK) == mTYthread)
{
DtBuilder dtb;
tlsToDt(vd, s, dtb);
s->Sdt = dtb.finish();
}
else if (vd->_init)
{
DtBuilder dtb;
initializerToDt(vd, dtb);
s->Sdt = dtb.finish();
}
else
{
DtBuilder dtb;
Type_toDt(vd->type, &dtb);
s->Sdt = dtb.finish();
}
// See if we can convert a comdat to a comdef,
// which saves on exe file space.
if (s->Sclass == SCcomdat &&
s->Sdt &&
dtallzeros(s->Sdt) &&
!vd->isThreadlocal())
{
s->Sclass = SCglobal;
dt2common(&s->Sdt);
}
if (!sz && vd->type->toBasetype()->ty != Tsarray)
assert(0); // this shouldn't be possible
if (sz || objmod->allowZeroSize())
{
outdata(s);
if (vd->isExport())
objmod->export_symbol(s, 0);
}
}
