// Compute the size and offset of a DIE. The offset is relative to start of the
// CU. It returns the offset after laying out the DIE.
unsigned DwarfFile::computeSizeAndOffset(DIE &Die, unsigned Offset) {
// Record the abbreviation.
assignAbbrevNumber(Die.getAbbrev());
// Get the abbreviation for this DIE.
const DIEAbbrev &Abbrev = Die.getAbbrev();
// Set DIE offset
Die.setOffset(Offset);
// Start the size with the size of abbreviation code.
Offset += getULEB128Size(Die.getAbbrevNumber());
const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
// Size the DIE attribute values.
for (unsigned i = 0, N = Values.size(); i < N; ++i)
// Size attribute value.
Offset += Values[i]->SizeOf(Asm, AbbrevData[i].getForm());
// Get the children.
const auto &Children = Die.getChildren();
// Size the DIE children if any.
if (!Children.empty()) {
assert(Abbrev.hasChildren() && "Children flag not set");
for (auto &Child : Children)
Offset = computeSizeAndOffset(*Child, Offset);
// End of children marker.
Offset += sizeof(int8_t);
}
Die.setSize(Offset - Die.getOffset());
return Offset;
}
void AsmPrinter::emitDwarfDIE(const DIE &Die) const {
// Get the abbreviation for this DIE.
const DIEAbbrev &Abbrev = Die.getAbbrev();
// Emit the code (index) for the abbreviation.
if (isVerbose())
OutStreamer.AddComment("Abbrev [" + Twine(Abbrev.getNumber()) +
"] 0x" + Twine::utohexstr(Die.getOffset()) +
":0x" + Twine::utohexstr(Die.getSize()) + " " +
dwarf::TagString(Abbrev.getTag()));
EmitULEB128(Abbrev.getNumber());
const SmallVectorImpl<DIEValue *> &Values = Die.getValues();
const SmallVectorImpl<DIEAbbrevData> &AbbrevData = Abbrev.getData();
// Emit the DIE attribute values.
for (unsigned i = 0, N = Values.size(); i < N; ++i) {
dwarf::Attribute Attr = AbbrevData[i].getAttribute();
dwarf::Form Form = AbbrevData[i].getForm();
assert(Form && "Too many attributes for DIE (check abbreviation)");
if (isVerbose()) {
OutStreamer.AddComment(dwarf::AttributeString(Attr));
if (Attr == dwarf::DW_AT_accessibility)
OutStreamer.AddComment(dwarf::AccessibilityString(
cast<DIEInteger>(Values[i])->getValue()));
}
// Emit an attribute using the defined form.
Values[i]->EmitValue(this, Form);
}
// Emit the DIE children if any.
if (Abbrev.hasChildren()) {
for (auto &Child : Die.getChildren())
emitDwarfDIE(Child);
OutStreamer.AddComment("End Of Children Mark");
EmitInt8(0);
}
}