4597dce483
Summary:
getRelocatedValue may compute incorrect value for SHT_RELA-typed relocation entries.
// DWARFDataExtractor.cpp
uint64_t DWARFDataExtractor::getRelocatedValue(uint32_t Size, uint32_t *Off,
...
// This formula is correct for REL, but may be incorrect for RELA if the value
// stored in the location (getUnsigned(Off, Size)) is not zero.
return getUnsigned(Off, Size) + Rel->Value;
In this patch, we
* refactor these visit* functions to include a new parameter `uint64_t A`.
Since these visit* functions are no longer used as visitors, rename them to resolve*.
+ REL: A is used as the addend. A is the value stored in the location where the
relocation applies: getUnsigned(Off, Size)
+ RELA: The addend encoded in RelocationRef is used, e.g. getELFAddend(R)
* and add another set of supports* functions to check if a given relocation type is handled.
DWARFObjInMemory uses them to fail early.
Reviewers: echristo, dblaikie
Reviewed By: echristo
Subscribers: mgorny, aprantl, aheejin, fedor.sergeev, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D57939
llvm-svn: 356729
97 lines
2.6 KiB
C++
97 lines
2.6 KiB
C++
//===- DWARFDataExtractor.cpp ---------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/DebugInfo/DWARF/DWARFDataExtractor.h"
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#include "llvm/BinaryFormat/Dwarf.h"
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#include "llvm/DebugInfo/DWARF/DWARFContext.h"
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using namespace llvm;
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uint64_t DWARFDataExtractor::getRelocatedValue(uint32_t Size, uint32_t *Off,
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uint64_t *SecNdx) const {
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if (SecNdx)
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*SecNdx = object::SectionedAddress::UndefSection;
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if (!Section)
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return getUnsigned(Off, Size);
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Optional<RelocAddrEntry> E = Obj->find(*Section, *Off);
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uint64_t A = getUnsigned(Off, Size);
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if (!E)
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return A;
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if (SecNdx)
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*SecNdx = E->SectionIndex;
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return E->Resolver(E->Reloc, E->SymbolValue, A);
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}
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Optional<uint64_t>
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DWARFDataExtractor::getEncodedPointer(uint32_t *Offset, uint8_t Encoding,
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uint64_t PCRelOffset) const {
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if (Encoding == dwarf::DW_EH_PE_omit)
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return None;
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uint64_t Result = 0;
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uint32_t OldOffset = *Offset;
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// First get value
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switch (Encoding & 0x0F) {
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case dwarf::DW_EH_PE_absptr:
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switch (getAddressSize()) {
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case 2:
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case 4:
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case 8:
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Result = getUnsigned(Offset, getAddressSize());
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break;
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default:
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return None;
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}
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break;
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case dwarf::DW_EH_PE_uleb128:
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Result = getULEB128(Offset);
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break;
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case dwarf::DW_EH_PE_sleb128:
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Result = getSLEB128(Offset);
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break;
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case dwarf::DW_EH_PE_udata2:
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Result = getUnsigned(Offset, 2);
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break;
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case dwarf::DW_EH_PE_udata4:
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Result = getUnsigned(Offset, 4);
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break;
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case dwarf::DW_EH_PE_udata8:
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Result = getUnsigned(Offset, 8);
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break;
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case dwarf::DW_EH_PE_sdata2:
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Result = getSigned(Offset, 2);
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break;
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case dwarf::DW_EH_PE_sdata4:
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Result = getSigned(Offset, 4);
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break;
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case dwarf::DW_EH_PE_sdata8:
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Result = getSigned(Offset, 8);
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break;
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default:
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return None;
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}
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// Then add relative offset, if required
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switch (Encoding & 0x70) {
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case dwarf::DW_EH_PE_absptr:
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// do nothing
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break;
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case dwarf::DW_EH_PE_pcrel:
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Result += PCRelOffset;
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break;
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case dwarf::DW_EH_PE_datarel:
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case dwarf::DW_EH_PE_textrel:
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case dwarf::DW_EH_PE_funcrel:
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case dwarf::DW_EH_PE_aligned:
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default:
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*Offset = OldOffset;
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return None;
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}
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return Result;
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}
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