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//===- DWARFAbbreviationDeclaration.cpp -----------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/DebugInfo/DWARF/DWARFAbbreviationDeclaration.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/Optional.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
#include "llvm/DebugInfo/DWARF/DWARFUnit.h"
#include "llvm/Support/DataExtractor.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/raw_ostream.h"
#include <cstddef>
#include <cstdint>
using namespace llvm;
using namespace dwarf;
void DWARFAbbreviationDeclaration::clear() {
Code = 0;
Tag = DW_TAG_null;
CodeByteSize = 0;
HasChildren = false;
AttributeSpecs.clear();
FixedAttributeSize.reset();
}
DWARFAbbreviationDeclaration::DWARFAbbreviationDeclaration() {
clear();
}
bool
DWARFAbbreviationDeclaration::extract(DataExtractor Data,
uint32_t* OffsetPtr) {
clear();
const uint32_t Offset = *OffsetPtr;
Code = Data.getULEB128(OffsetPtr);
if (Code == 0) {
return false;
}
CodeByteSize = *OffsetPtr - Offset;
Tag = static_cast<llvm::dwarf::Tag>(Data.getULEB128(OffsetPtr));
if (Tag == DW_TAG_null) {
clear();
return false;
}
uint8_t ChildrenByte = Data.getU8(OffsetPtr);
HasChildren = (ChildrenByte == DW_CHILDREN_yes);
// Assign a value to our optional FixedAttributeSize member variable. If
// this member variable still has a value after the while loop below, then
// all attribute data in this abbreviation declaration has a fixed byte size.
FixedAttributeSize = FixedSizeInfo();
// Read all of the abbreviation attributes and forms.
while (true) {
auto A = static_cast<Attribute>(Data.getULEB128(OffsetPtr));
auto F = static_cast<Form>(Data.getULEB128(OffsetPtr));
if (A && F) {
bool IsImplicitConst = (F == DW_FORM_implicit_const);
if (IsImplicitConst) {
int64_t V = Data.getSLEB128(OffsetPtr);
AttributeSpecs.push_back(AttributeSpec(A, F, V));
continue;
}
Optional<uint8_t> ByteSize;
// If this abbrevation still has a fixed byte size, then update the
// FixedAttributeSize as needed.
switch (F) {
case DW_FORM_addr:
if (FixedAttributeSize)
++FixedAttributeSize->NumAddrs;
break;
case DW_FORM_ref_addr:
if (FixedAttributeSize)
++FixedAttributeSize->NumRefAddrs;
break;
case DW_FORM_strp:
case DW_FORM_GNU_ref_alt:
case DW_FORM_GNU_strp_alt:
case DW_FORM_line_strp:
case DW_FORM_sec_offset:
case DW_FORM_strp_sup:
if (FixedAttributeSize)
++FixedAttributeSize->NumDwarfOffsets;
break;
default:
// The form has a byte size that doesn't depend on Params.
// If it's a fixed size, keep track of it.
if ((ByteSize =
DWARFFormValue::getFixedByteSize(F, DWARFFormParams()))) {
if (FixedAttributeSize)
FixedAttributeSize->NumBytes += *ByteSize;
break;
}
// Indicate we no longer have a fixed byte size for this
// abbreviation by clearing the FixedAttributeSize optional value
// so it doesn't have a value.
FixedAttributeSize.reset();
break;
}
// Record this attribute and its fixed size if it has one.
AttributeSpecs.push_back(AttributeSpec(A, F, ByteSize));
} else if (A == 0 && F == 0) {
// We successfully reached the end of this abbreviation declaration
// since both attribute and form are zero.
break;
} else {
// Attribute and form pairs must either both be non-zero, in which case
// they are added to the abbreviation declaration, or both be zero to
// terminate the abbrevation declaration. In this case only one was
// zero which is an error.
clear();
return false;
}
}
return true;
}
void DWARFAbbreviationDeclaration::dump(raw_ostream &OS) const {
auto tagString = TagString(getTag());
OS << '[' << getCode() << "] ";
if (!tagString.empty())
OS << tagString;
else
OS << format("DW_TAG_Unknown_%x", getTag());
OS << "\tDW_CHILDREN_" << (hasChildren() ? "yes" : "no") << '\n';
for (const AttributeSpec &Spec : AttributeSpecs) {
OS << '\t';
auto attrString = AttributeString(Spec.Attr);
if (!attrString.empty())
OS << attrString;
else
OS << format("DW_AT_Unknown_%x", Spec.Attr);
OS << '\t';
auto formString = FormEncodingString(Spec.Form);
if (!formString.empty())
OS << formString;
else
OS << format("DW_FORM_Unknown_%x", Spec.Form);
if (Spec.isImplicitConst())
OS << '\t' << Spec.getImplicitConstValue();
OS << '\n';
}
OS << '\n';
}
Optional<uint32_t>
DWARFAbbreviationDeclaration::findAttributeIndex(dwarf::Attribute Attr) const {
for (uint32_t i = 0, e = AttributeSpecs.size(); i != e; ++i) {
if (AttributeSpecs[i].Attr == Attr)
return i;
}
return None;
}
Optional<DWARFFormValue> DWARFAbbreviationDeclaration::getAttributeValue(
const uint32_t DIEOffset, const dwarf::Attribute Attr,
const DWARFUnit &U) const {
Optional<uint32_t> MatchAttrIndex = findAttributeIndex(Attr);
if (!MatchAttrIndex)
return None;
auto DebugInfoData = U.getDebugInfoExtractor();
// Add the byte size of ULEB that for the abbrev Code so we can start
// skipping the attribute data.
uint32_t Offset = DIEOffset + CodeByteSize;
uint32_t AttrIndex = 0;
for (const auto &Spec : AttributeSpecs) {
if (*MatchAttrIndex == AttrIndex) {
// We have arrived at the attribute to extract, extract if from Offset.
DWARFFormValue FormValue(Spec.Form);
if (Spec.isImplicitConst()) {
FormValue.setSValue(Spec.getImplicitConstValue());
return FormValue;
}
if (FormValue.extractValue(DebugInfoData, &Offset, U.getFormParams(), &U))
return FormValue;
}
// March Offset along until we get to the attribute we want.
if (auto FixedSize = Spec.getByteSize(U))
Offset += *FixedSize;
else
DWARFFormValue::skipValue(Spec.Form, DebugInfoData, &Offset,
U.getFormParams());
++AttrIndex;
}
return None;
}
size_t DWARFAbbreviationDeclaration::FixedSizeInfo::getByteSize(
const DWARFUnit &U) const {
size_t ByteSize = NumBytes;
if (NumAddrs)
ByteSize += NumAddrs * U.getAddressByteSize();
if (NumRefAddrs)
ByteSize += NumRefAddrs * U.getRefAddrByteSize();
if (NumDwarfOffsets)
ByteSize += NumDwarfOffsets * U.getDwarfOffsetByteSize();
return ByteSize;
}
Optional<int64_t> DWARFAbbreviationDeclaration::AttributeSpec::getByteSize(
const DWARFUnit &U) const {
if (isImplicitConst())
return 0;
if (ByteSize.HasByteSize)
return ByteSize.ByteSize;
Optional<int64_t> S;
auto FixedByteSize =
DWARFFormValue::getFixedByteSize(Form, U.getFormParams());
if (FixedByteSize)
S = *FixedByteSize;
return S;
}
Optional<size_t> DWARFAbbreviationDeclaration::getFixedAttributesByteSize(
const DWARFUnit &U) const {
if (FixedAttributeSize)
return FixedAttributeSize->getByteSize(U);
return None;
}
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