for (j = i; j != -1; j = GlobalSet.find_next(j)) {
Type *Ty = Globals[j]->getValueType();
- // Make sure we use the same alignment AsmPrinter would use. There
- // currently isn't any helper to compute that, so we compute it
- // explicitly here.
- //
- // getPreferredAlignment will sometimes return an alignment higher
- // than the explicitly specified alignment; we must ignore that
- // if the section is explicitly specified, to avoid inserting extra
- // padding into that section.
+ // Make sure we use the same alignment AsmPrinter would use.
unsigned Align = DL.getPreferredAlignment(Globals[j]);
- if (Globals[j]->hasSection() && Globals[j]->getAlignment())
- Align = Globals[j]->getAlignment();
unsigned Padding = alignTo(MergedSize, Align) - MergedSize;
MergedSize += Padding;
MergedSize += DL.getTypeAllocSize(Ty);
/// global. This includes an explicitly requested alignment (if the global
/// has one).
unsigned DataLayout::getPreferredAlignment(const GlobalVariable *GV) const {
+ unsigned GVAlignment = GV->getAlignment();
+ // If a section is specified, always precisely honor explicit alignment,
+ // so we don't insert padding into a section we don't control.
+ if (GVAlignment && GV->hasSection())
+ return GVAlignment;
+
+ // If no explicit alignment is specified, compute the alignment based on
+ // the IR type. If an alignment is specified, increase it to match the ABI
+ // alignment of the IR type.
+ //
+ // FIXME: Not sure it makes sense to use the alignment of the type if
+ // there's already an explicit alignment specification.
Type *ElemType = GV->getValueType();
unsigned Alignment = getPrefTypeAlignment(ElemType);
- unsigned GVAlignment = GV->getAlignment();
if (GVAlignment >= Alignment) {
Alignment = GVAlignment;
} else if (GVAlignment != 0) {
Alignment = std::max(GVAlignment, getABITypeAlignment(ElemType));
}
+ // If no explicit alignment is specified, and the global is large, increase
+ // the alignment to 16.
+ // FIXME: Why 16, specifically?
if (GV->hasInitializer() && GVAlignment == 0) {
if (Alignment < 16) {
// If the global is not external, see if it is large. If so, give it a