llvm/lib/DebugInfo/DWARF/DWARFListTable.cpp
Alex Bradbury bfd9349162 [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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@366402 91177308-0d34-0410-b5e6-96231b3b80d8
2019-07-18 05:22:55 +00:00

109 lines
4.8 KiB
C++

//===- DWARFListTable.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/DWARFListTable.h"
#include "llvm/BinaryFormat/Dwarf.h"
#include "llvm/Support/Errc.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
Error DWARFListTableHeader::extract(DWARFDataExtractor Data,
uint32_t *OffsetPtr) {
HeaderOffset = *OffsetPtr;
// Read and verify the length field.
if (!Data.isValidOffsetForDataOfSize(*OffsetPtr, sizeof(uint32_t)))
return createStringError(errc::invalid_argument,
"section is not large enough to contain a "
"%s table length at offset 0x%" PRIx32,
SectionName.data(), *OffsetPtr);
// TODO: Add support for DWARF64.
HeaderData.Length = Data.getRelocatedValue(4, OffsetPtr);
if (HeaderData.Length == 0xffffffffu)
return createStringError(errc::not_supported,
"DWARF64 is not supported in %s at offset 0x%" PRIx32,
SectionName.data(), HeaderOffset);
Format = dwarf::DwarfFormat::DWARF32;
if (HeaderData.Length + sizeof(uint32_t) < sizeof(Header))
return createStringError(errc::invalid_argument,
"%s table at offset 0x%" PRIx32
" has too small length (0x%" PRIx32
") to contain a complete header",
SectionName.data(), HeaderOffset, length());
uint32_t End = HeaderOffset + length();
if (!Data.isValidOffsetForDataOfSize(HeaderOffset, End - HeaderOffset))
return createStringError(errc::invalid_argument,
"section is not large enough to contain a %s table "
"of length 0x%" PRIx32 " at offset 0x%" PRIx32,
SectionName.data(), length(), HeaderOffset);
HeaderData.Version = Data.getU16(OffsetPtr);
HeaderData.AddrSize = Data.getU8(OffsetPtr);
HeaderData.SegSize = Data.getU8(OffsetPtr);
HeaderData.OffsetEntryCount = Data.getU32(OffsetPtr);
// Perform basic validation of the remaining header fields.
if (HeaderData.Version != 5)
return createStringError(errc::invalid_argument,
"unrecognised %s table version %" PRIu16
" in table at offset 0x%" PRIx32,
SectionName.data(), HeaderData.Version, HeaderOffset);
if (HeaderData.AddrSize != 4 && HeaderData.AddrSize != 8)
return createStringError(errc::not_supported,
"%s table at offset 0x%" PRIx32
" has unsupported address size %" PRIu8,
SectionName.data(), HeaderOffset, HeaderData.AddrSize);
if (HeaderData.SegSize != 0)
return createStringError(errc::not_supported,
"%s table at offset 0x%" PRIx32
" has unsupported segment selector size %" PRIu8,
SectionName.data(), HeaderOffset, HeaderData.SegSize);
if (End < HeaderOffset + sizeof(HeaderData) +
HeaderData.OffsetEntryCount * sizeof(uint32_t))
return createStringError(errc::invalid_argument,
"%s table at offset 0x%" PRIx32 " has more offset entries (%" PRIu32
") than there is space for",
SectionName.data(), HeaderOffset, HeaderData.OffsetEntryCount);
Data.setAddressSize(HeaderData.AddrSize);
for (uint32_t I = 0; I < HeaderData.OffsetEntryCount; ++I)
Offsets.push_back(Data.getRelocatedValue(4, OffsetPtr));
return Error::success();
}
void DWARFListTableHeader::dump(raw_ostream &OS, DIDumpOptions DumpOpts) const {
if (DumpOpts.Verbose)
OS << format("0x%8.8" PRIx32 ": ", HeaderOffset);
OS << format(
"%s list header: length = 0x%8.8" PRIx32 ", version = 0x%4.4" PRIx16 ", "
"addr_size = 0x%2.2" PRIx8 ", seg_size = 0x%2.2" PRIx8
", offset_entry_count = "
"0x%8.8" PRIx32 "\n",
ListTypeString.data(), HeaderData.Length, HeaderData.Version,
HeaderData.AddrSize, HeaderData.SegSize, HeaderData.OffsetEntryCount);
if (HeaderData.OffsetEntryCount > 0) {
OS << "offsets: [";
for (const auto &Off : Offsets) {
OS << format("\n0x%8.8" PRIx32, Off);
if (DumpOpts.Verbose)
OS << format(" => 0x%8.8" PRIx32,
Off + HeaderOffset + sizeof(HeaderData));
}
OS << "\n]\n";
}
}
uint32_t DWARFListTableHeader::length() const {
if (HeaderData.Length == 0)
return 0;
// TODO: DWARF64 support.
return HeaderData.Length + sizeof(uint32_t);
}