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clang-p2996/llvm/lib/DebugInfo/DWARF/DWARFFormValue.cpp
Alex Bradbury 44deaf7e54 [DWARF][RISCV] Add support for RISC-V relocations needed for debug info 
When code relaxation is enabled many RISC-V fixups are not resolved but
instead relocations are emitted. This happens even for DWARF debug
sections. Therefore, to properly support the parsing of DWARF debug info
we need to be able to resolve RISC-V relocations. This patch adds:

* Support for RISC-V relocations in RelocationResolver
* DWARF support for two relocations per object file offset
* DWARF changes to support relocations in more DIE fields

The two relocations per offset change is needed because some RISC-V
relocations (used for label differences) come in pairs.

Relocations can also be emitted for DWARF fields where relocations were
not yet evaluated. Adding relocation support for some of these fields is
essencial. On the other hand, LLVM currently emits RISC-V relocations
for fixups that could be safely evaluated, since they can never be
affected by code relaxations. This patch also adds relocation support
for the fields affected by those extraneous relocations (the DWARF unit
entry Length, and the DWARF debug line entry TotalLength and
PrologueLength), for testing purposes.

Differential Revision: https://reviews.llvm.org/D62062
Patch by Luís Marques.

llvm-svn: 366402
2019-07-18 05:22:55 +00:00

720 lines
21 KiB
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Raw Blame History

//===- DWARFFormValue.cpp -------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/DebugInfo/DWARF/DWARFFormValue.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/DebugInfo/DWARF/DWARFContext.h"
#include "llvm/DebugInfo/DWARF/DWARFRelocMap.h"
#include "llvm/DebugInfo/DWARF/DWARFUnit.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/WithColor.h"
#include "llvm/Support/raw_ostream.h"
#include <cinttypes>
#include <cstdint>
#include <limits>
using namespace llvm;
using namespace dwarf;
static const DWARFFormValue::FormClass DWARF5FormClasses[] = {
DWARFFormValue::FC_Unknown, // 0x0
DWARFFormValue::FC_Address, // 0x01 DW_FORM_addr
DWARFFormValue::FC_Unknown, // 0x02 unused
DWARFFormValue::FC_Block, // 0x03 DW_FORM_block2
DWARFFormValue::FC_Block, // 0x04 DW_FORM_block4
DWARFFormValue::FC_Constant, // 0x05 DW_FORM_data2
// --- These can be FC_SectionOffset in DWARF3 and below:
DWARFFormValue::FC_Constant, // 0x06 DW_FORM_data4
DWARFFormValue::FC_Constant, // 0x07 DW_FORM_data8
// ---
DWARFFormValue::FC_String, // 0x08 DW_FORM_string
DWARFFormValue::FC_Block, // 0x09 DW_FORM_block
DWARFFormValue::FC_Block, // 0x0a DW_FORM_block1
DWARFFormValue::FC_Constant, // 0x0b DW_FORM_data1
DWARFFormValue::FC_Flag, // 0x0c DW_FORM_flag
DWARFFormValue::FC_Constant, // 0x0d DW_FORM_sdata
DWARFFormValue::FC_String, // 0x0e DW_FORM_strp
DWARFFormValue::FC_Constant, // 0x0f DW_FORM_udata
DWARFFormValue::FC_Reference, // 0x10 DW_FORM_ref_addr
DWARFFormValue::FC_Reference, // 0x11 DW_FORM_ref1
DWARFFormValue::FC_Reference, // 0x12 DW_FORM_ref2
DWARFFormValue::FC_Reference, // 0x13 DW_FORM_ref4
DWARFFormValue::FC_Reference, // 0x14 DW_FORM_ref8
DWARFFormValue::FC_Reference, // 0x15 DW_FORM_ref_udata
DWARFFormValue::FC_Indirect, // 0x16 DW_FORM_indirect
DWARFFormValue::FC_SectionOffset, // 0x17 DW_FORM_sec_offset
DWARFFormValue::FC_Exprloc, // 0x18 DW_FORM_exprloc
DWARFFormValue::FC_Flag, // 0x19 DW_FORM_flag_present
DWARFFormValue::FC_String, // 0x1a DW_FORM_strx
DWARFFormValue::FC_Address, // 0x1b DW_FORM_addrx
DWARFFormValue::FC_Reference, // 0x1c DW_FORM_ref_sup4
DWARFFormValue::FC_String, // 0x1d DW_FORM_strp_sup
DWARFFormValue::FC_Constant, // 0x1e DW_FORM_data16
DWARFFormValue::FC_String, // 0x1f DW_FORM_line_strp
DWARFFormValue::FC_Reference, // 0x20 DW_FORM_ref_sig8
DWARFFormValue::FC_Constant, // 0x21 DW_FORM_implicit_const
DWARFFormValue::FC_SectionOffset, // 0x22 DW_FORM_loclistx
DWARFFormValue::FC_SectionOffset, // 0x23 DW_FORM_rnglistx
DWARFFormValue::FC_Reference, // 0x24 DW_FORM_ref_sup8
DWARFFormValue::FC_String, // 0x25 DW_FORM_strx1
DWARFFormValue::FC_String, // 0x26 DW_FORM_strx2
DWARFFormValue::FC_String, // 0x27 DW_FORM_strx3
DWARFFormValue::FC_String, // 0x28 DW_FORM_strx4
DWARFFormValue::FC_Address, // 0x29 DW_FORM_addrx1
DWARFFormValue::FC_Address, // 0x2a DW_FORM_addrx2
DWARFFormValue::FC_Address, // 0x2b DW_FORM_addrx3
DWARFFormValue::FC_Address, // 0x2c DW_FORM_addrx4
};
DWARFFormValue DWARFFormValue::createFromSValue(dwarf::Form F, int64_t V) {
return DWARFFormValue(F, ValueType(V));
}
DWARFFormValue DWARFFormValue::createFromUValue(dwarf::Form F, uint64_t V) {
return DWARFFormValue(F, ValueType(V));
}
DWARFFormValue DWARFFormValue::createFromPValue(dwarf::Form F, const char *V) {
return DWARFFormValue(F, ValueType(V));
}
DWARFFormValue DWARFFormValue::createFromBlockValue(dwarf::Form F,
ArrayRef<uint8_t> D) {
ValueType V;
V.uval = D.size();
V.data = D.data();
return DWARFFormValue(F, V);
}
DWARFFormValue DWARFFormValue::createFromUnit(dwarf::Form F, const DWARFUnit *U,
uint32_t *OffsetPtr) {
DWARFFormValue FormValue(F);
FormValue.extractValue(U->getDebugInfoExtractor(), OffsetPtr,
U->getFormParams(), U);
return FormValue;
}
bool DWARFFormValue::skipValue(dwarf::Form Form, DataExtractor DebugInfoData,
uint32_t *OffsetPtr,
const dwarf::FormParams Params) {
bool Indirect = false;
do {
switch (Form) {
// Blocks of inlined data that have a length field and the data bytes
// inlined in the .debug_info.
case DW_FORM_exprloc:
case DW_FORM_block: {
uint64_t size = DebugInfoData.getULEB128(OffsetPtr);
*OffsetPtr += size;
return true;
}
case DW_FORM_block1: {
uint8_t size = DebugInfoData.getU8(OffsetPtr);
*OffsetPtr += size;
return true;
}
case DW_FORM_block2: {
uint16_t size = DebugInfoData.getU16(OffsetPtr);
*OffsetPtr += size;
return true;
}
case DW_FORM_block4: {
uint32_t size = DebugInfoData.getU32(OffsetPtr);
*OffsetPtr += size;
return true;
}
// Inlined NULL terminated C-strings.
case DW_FORM_string:
DebugInfoData.getCStr(OffsetPtr);
return true;
case DW_FORM_addr:
case DW_FORM_ref_addr:
case DW_FORM_flag_present:
case DW_FORM_data1:
case DW_FORM_data2:
case DW_FORM_data4:
case DW_FORM_data8:
case DW_FORM_data16:
case DW_FORM_flag:
case DW_FORM_ref1:
case DW_FORM_ref2:
case DW_FORM_ref4:
case DW_FORM_ref8:
case DW_FORM_ref_sig8:
case DW_FORM_ref_sup4:
case DW_FORM_ref_sup8:
case DW_FORM_strx1:
case DW_FORM_strx2:
case DW_FORM_strx4:
case DW_FORM_addrx1:
case DW_FORM_addrx2:
case DW_FORM_addrx4:
case DW_FORM_sec_offset:
case DW_FORM_strp:
case DW_FORM_strp_sup:
case DW_FORM_line_strp:
case DW_FORM_GNU_ref_alt:
case DW_FORM_GNU_strp_alt:
if (Optional<uint8_t> FixedSize =
dwarf::getFixedFormByteSize(Form, Params)) {
*OffsetPtr += *FixedSize;
return true;
}
return false;
// signed or unsigned LEB 128 values.
case DW_FORM_sdata:
DebugInfoData.getSLEB128(OffsetPtr);
return true;
case DW_FORM_udata:
case DW_FORM_ref_udata:
case DW_FORM_strx:
case DW_FORM_addrx:
case DW_FORM_loclistx:
case DW_FORM_rnglistx:
case DW_FORM_GNU_addr_index:
case DW_FORM_GNU_str_index:
DebugInfoData.getULEB128(OffsetPtr);
return true;
case DW_FORM_indirect:
Indirect = true;
Form = static_cast<dwarf::Form>(DebugInfoData.getULEB128(OffsetPtr));
break;
default:
return false;
}
} while (Indirect);
return true;
}
bool DWARFFormValue::isFormClass(DWARFFormValue::FormClass FC) const {
// First, check DWARF5 form classes.
if (Form < makeArrayRef(DWARF5FormClasses).size() &&
DWARF5FormClasses[Form] == FC)
return true;
// Check more forms from extensions and proposals.
switch (Form) {
case DW_FORM_GNU_ref_alt:
return (FC == FC_Reference);
case DW_FORM_GNU_addr_index:
return (FC == FC_Address);
case DW_FORM_GNU_str_index:
case DW_FORM_GNU_strp_alt:
return (FC == FC_String);
default:
break;
}
if (FC == FC_SectionOffset) {
if (Form == DW_FORM_strp || Form == DW_FORM_line_strp)
return true;
// In DWARF3 DW_FORM_data4 and DW_FORM_data8 served also as a section
// offset. If we don't have a DWARFUnit, default to the old behavior.
if (Form == DW_FORM_data4 || Form == DW_FORM_data8)
return !U || U->getVersion() <= 3;
}
return false;
}
bool DWARFFormValue::extractValue(const DWARFDataExtractor &Data,
uint32_t *OffsetPtr, dwarf::FormParams FP,
const DWARFContext *Ctx,
const DWARFUnit *CU) {
if (!Ctx && CU)
Ctx = &CU->getContext();
C = Ctx;
U = CU;
bool Indirect = false;
bool IsBlock = false;
Value.data = nullptr;
// Read the value for the form into value and follow and DW_FORM_indirect
// instances we run into
do {
Indirect = false;
switch (Form) {
case DW_FORM_addr:
case DW_FORM_ref_addr: {
uint16_t Size =
(Form == DW_FORM_addr) ? FP.AddrSize : FP.getRefAddrByteSize();
Value.uval = Data.getRelocatedValue(Size, OffsetPtr, &Value.SectionIndex);
break;
}
case DW_FORM_exprloc:
case DW_FORM_block:
Value.uval = Data.getULEB128(OffsetPtr);
IsBlock = true;
break;
case DW_FORM_block1:
Value.uval = Data.getU8(OffsetPtr);
IsBlock = true;
break;
case DW_FORM_block2:
Value.uval = Data.getU16(OffsetPtr);
IsBlock = true;
break;
case DW_FORM_block4:
Value.uval = Data.getU32(OffsetPtr);
IsBlock = true;
break;
case DW_FORM_data1:
case DW_FORM_ref1:
case DW_FORM_flag:
case DW_FORM_strx1:
case DW_FORM_addrx1:
Value.uval = Data.getU8(OffsetPtr);
break;
case DW_FORM_data2:
case DW_FORM_ref2:
case DW_FORM_strx2:
case DW_FORM_addrx2:
Value.uval = Data.getU16(OffsetPtr);
break;
case DW_FORM_strx3:
Value.uval = Data.getU24(OffsetPtr);
break;
case DW_FORM_data4:
case DW_FORM_ref4:
case DW_FORM_ref_sup4:
case DW_FORM_strx4:
case DW_FORM_addrx4:
Value.uval = Data.getRelocatedValue(4, OffsetPtr);
break;
case DW_FORM_data8:
case DW_FORM_ref8:
case DW_FORM_ref_sup8:
Value.uval = Data.getRelocatedValue(8, OffsetPtr);
break;
case DW_FORM_data16:
// Treat this like a 16-byte block.
Value.uval = 16;
IsBlock = true;
break;
case DW_FORM_sdata:
Value.sval = Data.getSLEB128(OffsetPtr);
break;
case DW_FORM_udata:
case DW_FORM_ref_udata:
case DW_FORM_rnglistx:
Value.uval = Data.getULEB128(OffsetPtr);
break;
case DW_FORM_string:
Value.cstr = Data.getCStr(OffsetPtr);
break;
case DW_FORM_indirect:
Form = static_cast<dwarf::Form>(Data.getULEB128(OffsetPtr));
Indirect = true;
break;
case DW_FORM_strp:
case DW_FORM_sec_offset:
case DW_FORM_GNU_ref_alt:
case DW_FORM_GNU_strp_alt:
case DW_FORM_line_strp:
case DW_FORM_strp_sup: {
Value.uval =
Data.getRelocatedValue(FP.getDwarfOffsetByteSize(), OffsetPtr);
break;
}
case DW_FORM_flag_present:
Value.uval = 1;
break;
case DW_FORM_ref_sig8:
Value.uval = Data.getU64(OffsetPtr);
break;
case DW_FORM_GNU_addr_index:
case DW_FORM_GNU_str_index:
case DW_FORM_addrx:
case DW_FORM_strx:
Value.uval = Data.getULEB128(OffsetPtr);
break;
default:
// DWARFFormValue::skipValue() will have caught this and caused all
// DWARF DIEs to fail to be parsed, so this code is not be reachable.
llvm_unreachable("unsupported form");
}
} while (Indirect);
if (IsBlock) {
StringRef Str = Data.getData().substr(*OffsetPtr, Value.uval);
Value.data = nullptr;
if (!Str.empty()) {
Value.data = Str.bytes_begin();
*OffsetPtr += Value.uval;
}
}
return true;
}
void DWARFFormValue::dumpSectionedAddress(raw_ostream &OS,
DIDumpOptions DumpOpts,
object::SectionedAddress SA) const {
OS << format("0x%016" PRIx64, SA.Address);
dumpAddressSection(U->getContext().getDWARFObj(), OS, DumpOpts,
SA.SectionIndex);
}
void DWARFFormValue::dumpAddressSection(const DWARFObject &Obj, raw_ostream &OS,
DIDumpOptions DumpOpts,
uint64_t SectionIndex) {
if (!DumpOpts.Verbose || SectionIndex == -1ULL)
return;
ArrayRef<SectionName> SectionNames = Obj.getSectionNames();
const auto &SecRef = SectionNames[SectionIndex];
OS << " \"" << SecRef.Name << '\"';
// Print section index if name is not unique.
if (!SecRef.IsNameUnique)
OS << format(" [%" PRIu64 "]", SectionIndex);
}
void DWARFFormValue::dump(raw_ostream &OS, DIDumpOptions DumpOpts) const {
uint64_t UValue = Value.uval;
bool CURelativeOffset = false;
raw_ostream &AddrOS = DumpOpts.ShowAddresses
? WithColor(OS, HighlightColor::Address).get()
: nulls();
switch (Form) {
case DW_FORM_addr:
dumpSectionedAddress(AddrOS, DumpOpts, {Value.uval, Value.SectionIndex});
break;
case DW_FORM_addrx:
case DW_FORM_addrx1:
case DW_FORM_addrx2:
case DW_FORM_addrx3:
case DW_FORM_addrx4:
case DW_FORM_GNU_addr_index: {
if (U == nullptr) {
OS << "<invalid dwarf unit>";
break;
}
Optional<object::SectionedAddress> A = U->getAddrOffsetSectionItem(UValue);
if (!A || DumpOpts.Verbose)
AddrOS << format("indexed (%8.8x) address = ", (uint32_t)UValue);
if (A)
dumpSectionedAddress(AddrOS, DumpOpts, *A);
else
OS << "<no .debug_addr section>";
break;
}
case DW_FORM_flag_present:
OS << "true";
break;
case DW_FORM_flag:
case DW_FORM_data1:
OS << format("0x%02x", (uint8_t)UValue);
break;
case DW_FORM_data2:
OS << format("0x%04x", (uint16_t)UValue);
break;
case DW_FORM_data4:
OS << format("0x%08x", (uint32_t)UValue);
break;
case DW_FORM_ref_sig8:
AddrOS << format("0x%016" PRIx64, UValue);
break;
case DW_FORM_data8:
OS << format("0x%016" PRIx64, UValue);
break;
case DW_FORM_data16:
OS << format_bytes(ArrayRef<uint8_t>(Value.data, 16), None, 16, 16);
break;
case DW_FORM_string:
OS << '"';
OS.write_escaped(Value.cstr);
OS << '"';
break;
case DW_FORM_exprloc:
case DW_FORM_block:
case DW_FORM_block1:
case DW_FORM_block2:
case DW_FORM_block4:
if (UValue > 0) {
switch (Form) {
case DW_FORM_exprloc:
case DW_FORM_block:
AddrOS << format("<0x%" PRIx64 "> ", UValue);
break;
case DW_FORM_block1:
AddrOS << format("<0x%2.2x> ", (uint8_t)UValue);
break;
case DW_FORM_block2:
AddrOS << format("<0x%4.4x> ", (uint16_t)UValue);
break;
case DW_FORM_block4:
AddrOS << format("<0x%8.8x> ", (uint32_t)UValue);
break;
default:
break;
}
const uint8_t *DataPtr = Value.data;
if (DataPtr) {
// UValue contains size of block
const uint8_t *EndDataPtr = DataPtr + UValue;
while (DataPtr < EndDataPtr) {
AddrOS << format("%2.2x ", *DataPtr);
++DataPtr;
}
} else
OS << "NULL";
}
break;
case DW_FORM_sdata:
OS << Value.sval;
break;
case DW_FORM_udata:
OS << Value.uval;
break;
case DW_FORM_strp:
if (DumpOpts.Verbose)
OS << format(" .debug_str[0x%8.8x] = ", (uint32_t)UValue);
dumpString(OS);
break;
case DW_FORM_line_strp:
if (DumpOpts.Verbose)
OS << format(" .debug_line_str[0x%8.8x] = ", (uint32_t)UValue);
dumpString(OS);
break;
case DW_FORM_strx:
case DW_FORM_strx1:
case DW_FORM_strx2:
case DW_FORM_strx3:
case DW_FORM_strx4:
case DW_FORM_GNU_str_index:
if (DumpOpts.Verbose)
OS << format("indexed (%8.8x) string = ", (uint32_t)UValue);
dumpString(OS);
break;
case DW_FORM_GNU_strp_alt:
if (DumpOpts.Verbose)
OS << format("alt indirect string, offset: 0x%" PRIx64 "", UValue);
dumpString(OS);
break;
case DW_FORM_ref_addr:
AddrOS << format("0x%016" PRIx64, UValue);
break;
case DW_FORM_ref1:
CURelativeOffset = true;
if (DumpOpts.Verbose)
AddrOS << format("cu + 0x%2.2x", (uint8_t)UValue);
break;
case DW_FORM_ref2:
CURelativeOffset = true;
if (DumpOpts.Verbose)
AddrOS << format("cu + 0x%4.4x", (uint16_t)UValue);
break;
case DW_FORM_ref4:
CURelativeOffset = true;
if (DumpOpts.Verbose)
AddrOS << format("cu + 0x%4.4x", (uint32_t)UValue);
break;
case DW_FORM_ref8:
CURelativeOffset = true;
if (DumpOpts.Verbose)
AddrOS << format("cu + 0x%8.8" PRIx64, UValue);
break;
case DW_FORM_ref_udata:
CURelativeOffset = true;
if (DumpOpts.Verbose)
AddrOS << format("cu + 0x%" PRIx64, UValue);
break;
case DW_FORM_GNU_ref_alt:
AddrOS << format("<alt 0x%" PRIx64 ">", UValue);
break;
// All DW_FORM_indirect attributes should be resolved prior to calling
// this function
case DW_FORM_indirect:
OS << "DW_FORM_indirect";
break;
case DW_FORM_rnglistx:
OS << format("indexed (0x%x) rangelist = ", (uint32_t)UValue);
break;
// Should be formatted to 64-bit for DWARF64.
case DW_FORM_sec_offset:
AddrOS << format("0x%08x", (uint32_t)UValue);
break;
default:
OS << format("DW_FORM(0x%4.4x)", Form);
break;
}
if (CURelativeOffset) {
if (DumpOpts.Verbose)
OS << " => {";
if (DumpOpts.ShowAddresses)
WithColor(OS, HighlightColor::Address).get()
<< format("0x%8.8" PRIx64, UValue + (U ? U->getOffset() : 0));
if (DumpOpts.Verbose)
OS << "}";
}
}
void DWARFFormValue::dumpString(raw_ostream &OS) const {
Optional<const char *> DbgStr = getAsCString();
if (DbgStr.hasValue()) {
auto COS = WithColor(OS, HighlightColor::String);
COS.get() << '"';
COS.get().write_escaped(DbgStr.getValue());
COS.get() << '"';
}
}
Optional<const char *> DWARFFormValue::getAsCString() const {
if (!isFormClass(FC_String))
return None;
if (Form == DW_FORM_string)
return Value.cstr;
// FIXME: Add support for DW_FORM_GNU_strp_alt
if (Form == DW_FORM_GNU_strp_alt || C == nullptr)
return None;
uint32_t Offset = Value.uval;
if (Form == DW_FORM_line_strp) {
// .debug_line_str is tracked in the Context.
if (const char *Str = C->getLineStringExtractor().getCStr(&Offset))
return Str;
return None;
}
if (Form == DW_FORM_GNU_str_index || Form == DW_FORM_strx ||
Form == DW_FORM_strx1 || Form == DW_FORM_strx2 || Form == DW_FORM_strx3 ||
Form == DW_FORM_strx4) {
if (!U)
return None;
Optional<uint64_t> StrOffset = U->getStringOffsetSectionItem(Offset);
if (!StrOffset)
return None;
Offset = *StrOffset;
}
// Prefer the Unit's string extractor, because for .dwo it will point to
// .debug_str.dwo, while the Context's extractor always uses .debug_str.
if (U) {
if (const char *Str = U->getStringExtractor().getCStr(&Offset))
return Str;
return None;
}
if (const char *Str = C->getStringExtractor().getCStr(&Offset))
return Str;
return None;
}
Optional<uint64_t> DWARFFormValue::getAsAddress() const {
if (auto SA = getAsSectionedAddress())
return SA->Address;
return None;
}
Optional<object::SectionedAddress>
DWARFFormValue::getAsSectionedAddress() const {
if (!isFormClass(FC_Address))
return None;
if (Form == DW_FORM_GNU_addr_index || Form == DW_FORM_addrx) {
uint32_t Index = Value.uval;
if (!U)
return None;
Optional<object::SectionedAddress> SA = U->getAddrOffsetSectionItem(Index);
if (!SA)
return None;
return SA;
}
return {{Value.uval, Value.SectionIndex}};
}
Optional<uint64_t> DWARFFormValue::getAsReference() const {
if (auto R = getAsRelativeReference())
return R->Unit ? R->Unit->getOffset() + R->Offset : R->Offset;
return None;
}
Optional<DWARFFormValue::UnitOffset> DWARFFormValue::getAsRelativeReference() const {
if (!isFormClass(FC_Reference))
return None;
switch (Form) {
case DW_FORM_ref1:
case DW_FORM_ref2:
case DW_FORM_ref4:
case DW_FORM_ref8:
case DW_FORM_ref_udata:
if (!U)
return None;
return UnitOffset{const_cast<DWARFUnit*>(U), Value.uval};
case DW_FORM_ref_addr:
case DW_FORM_ref_sig8:
case DW_FORM_GNU_ref_alt:
return UnitOffset{nullptr, Value.uval};
default:
return None;
}
}
Optional<uint64_t> DWARFFormValue::getAsSectionOffset() const {
if (!isFormClass(FC_SectionOffset))
return None;
return Value.uval;
}
Optional<uint64_t> DWARFFormValue::getAsUnsignedConstant() const {
if ((!isFormClass(FC_Constant) && !isFormClass(FC_Flag)) ||
Form == DW_FORM_sdata)
return None;
return Value.uval;
}
Optional<int64_t> DWARFFormValue::getAsSignedConstant() const {
if ((!isFormClass(FC_Constant) && !isFormClass(FC_Flag)) ||
(Form == DW_FORM_udata &&
uint64_t(std::numeric_limits<int64_t>::max()) < Value.uval))
return None;
switch (Form) {
case DW_FORM_data4:
return int32_t(Value.uval);
case DW_FORM_data2:
return int16_t(Value.uval);
case DW_FORM_data1:
return int8_t(Value.uval);
case DW_FORM_sdata:
case DW_FORM_data8:
default:
return Value.sval;
}
}
Optional<ArrayRef<uint8_t>> DWARFFormValue::getAsBlock() const {
if (!isFormClass(FC_Block) && !isFormClass(FC_Exprloc) &&
Form != DW_FORM_data16)
return None;
return makeArrayRef(Value.data, Value.uval);
}
Optional<uint64_t> DWARFFormValue::getAsCStringOffset() const {
if (!isFormClass(FC_String) && Form == DW_FORM_string)
return None;
return Value.uval;
}
Optional<uint64_t> DWARFFormValue::getAsReferenceUVal() const {
if (!isFormClass(FC_Reference))
return None;
return Value.uval;
}
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