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| author | 2020-08-03 15:06:44 +0000 | |
|---|---|---|
| committer | 2020-08-03 15:06:44 +0000 | |
| commit | b64793999546ed8adebaeebd9d8345d18db8927d (patch) | |
| tree | 4357c27b561d73b0e089727c6ed659f2ceff5f47 /gnu/llvm/tools/lld/ELF/EhFrame.cpp | |
| parent | Add support for UTF-8 DISPLAY-HINTs with octet length. For now only (diff) | |
| download | wireguard-openbsd-b64793999546ed8adebaeebd9d8345d18db8927d.tar.xz wireguard-openbsd-b64793999546ed8adebaeebd9d8345d18db8927d.zip | |
Remove LLVM 8.0.1 files.
Diffstat (limited to 'gnu/llvm/tools/lld/ELF/EhFrame.cpp')
| -rw-r--r-- | gnu/llvm/tools/lld/ELF/EhFrame.cpp | 198 |
1 files changed, 0 insertions, 198 deletions
diff --git a/gnu/llvm/tools/lld/ELF/EhFrame.cpp b/gnu/llvm/tools/lld/ELF/EhFrame.cpp deleted file mode 100644 index 95d444bdc2a..00000000000 --- a/gnu/llvm/tools/lld/ELF/EhFrame.cpp +++ /dev/null @@ -1,198 +0,0 @@ -//===- EhFrame.cpp -------------------------------------------------------===// -// -// The LLVM Linker -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// -// -// .eh_frame section contains information on how to unwind the stack when -// an exception is thrown. The section consists of sequence of CIE and FDE -// records. The linker needs to merge CIEs and associate FDEs to CIEs. -// That means the linker has to understand the format of the section. -// -// This file contains a few utility functions to read .eh_frame contents. -// -//===----------------------------------------------------------------------===// - -#include "EhFrame.h" -#include "Config.h" -#include "InputSection.h" -#include "Relocations.h" -#include "Target.h" -#include "lld/Common/ErrorHandler.h" -#include "lld/Common/Strings.h" -#include "llvm/BinaryFormat/Dwarf.h" -#include "llvm/Object/ELF.h" - -using namespace llvm; -using namespace llvm::ELF; -using namespace llvm::dwarf; -using namespace llvm::object; - -using namespace lld; -using namespace lld::elf; - -namespace { -class EhReader { -public: - EhReader(InputSectionBase *S, ArrayRef<uint8_t> D) : IS(S), D(D) {} - size_t readEhRecordSize(); - uint8_t getFdeEncoding(); - -private: - template <class P> void failOn(const P *Loc, const Twine &Msg) { - fatal("corrupted .eh_frame: " + Msg + "\n>>> defined in " + - IS->getObjMsg((const uint8_t *)Loc - IS->data().data())); - } - - uint8_t readByte(); - void skipBytes(size_t Count); - StringRef readString(); - void skipLeb128(); - void skipAugP(); - - InputSectionBase *IS; - ArrayRef<uint8_t> D; -}; -} - -size_t elf::readEhRecordSize(InputSectionBase *S, size_t Off) { - return EhReader(S, S->data().slice(Off)).readEhRecordSize(); -} - -// .eh_frame section is a sequence of records. Each record starts with -// a 4 byte length field. This function reads the length. -size_t EhReader::readEhRecordSize() { - if (D.size() < 4) - failOn(D.data(), "CIE/FDE too small"); - - // First 4 bytes of CIE/FDE is the size of the record. - // If it is 0xFFFFFFFF, the next 8 bytes contain the size instead, - // but we do not support that format yet. - uint64_t V = read32(D.data()); - if (V == UINT32_MAX) - failOn(D.data(), "CIE/FDE too large"); - uint64_t Size = V + 4; - if (Size > D.size()) - failOn(D.data(), "CIE/FDE ends past the end of the section"); - return Size; -} - -// Read a byte and advance D by one byte. -uint8_t EhReader::readByte() { - if (D.empty()) - failOn(D.data(), "unexpected end of CIE"); - uint8_t B = D.front(); - D = D.slice(1); - return B; -} - -void EhReader::skipBytes(size_t Count) { - if (D.size() < Count) - failOn(D.data(), "CIE is too small"); - D = D.slice(Count); -} - -// Read a null-terminated string. -StringRef EhReader::readString() { - const uint8_t *End = std::find(D.begin(), D.end(), '\0'); - if (End == D.end()) - failOn(D.data(), "corrupted CIE (failed to read string)"); - StringRef S = toStringRef(D.slice(0, End - D.begin())); - D = D.slice(S.size() + 1); - return S; -} - -// Skip an integer encoded in the LEB128 format. -// Actual number is not of interest because only the runtime needs it. -// But we need to be at least able to skip it so that we can read -// the field that follows a LEB128 number. -void EhReader::skipLeb128() { - const uint8_t *ErrPos = D.data(); - while (!D.empty()) { - uint8_t Val = D.front(); - D = D.slice(1); - if ((Val & 0x80) == 0) - return; - } - failOn(ErrPos, "corrupted CIE (failed to read LEB128)"); -} - -static size_t getAugPSize(unsigned Enc) { - switch (Enc & 0x0f) { - case DW_EH_PE_absptr: - case DW_EH_PE_signed: - return Config->Wordsize; - case DW_EH_PE_udata2: - case DW_EH_PE_sdata2: - return 2; - case DW_EH_PE_udata4: - case DW_EH_PE_sdata4: - return 4; - case DW_EH_PE_udata8: - case DW_EH_PE_sdata8: - return 8; - } - return 0; -} - -void EhReader::skipAugP() { - uint8_t Enc = readByte(); - if ((Enc & 0xf0) == DW_EH_PE_aligned) - failOn(D.data() - 1, "DW_EH_PE_aligned encoding is not supported"); - size_t Size = getAugPSize(Enc); - if (Size == 0) - failOn(D.data() - 1, "unknown FDE encoding"); - if (Size >= D.size()) - failOn(D.data() - 1, "corrupted CIE"); - D = D.slice(Size); -} - -uint8_t elf::getFdeEncoding(EhSectionPiece *P) { - return EhReader(P->Sec, P->data()).getFdeEncoding(); -} - -uint8_t EhReader::getFdeEncoding() { - skipBytes(8); - int Version = readByte(); - if (Version != 1 && Version != 3) - failOn(D.data() - 1, - "FDE version 1 or 3 expected, but got " + Twine(Version)); - - StringRef Aug = readString(); - - // Skip code and data alignment factors. - skipLeb128(); - skipLeb128(); - - // Skip the return address register. In CIE version 1 this is a single - // byte. In CIE version 3 this is an unsigned LEB128. - if (Version == 1) - readByte(); - else - skipLeb128(); - - // We only care about an 'R' value, but other records may precede an 'R' - // record. Unfortunately records are not in TLV (type-length-value) format, - // so we need to teach the linker how to skip records for each type. - for (char C : Aug) { - if (C == 'R') - return readByte(); - if (C == 'z') { - skipLeb128(); - continue; - } - if (C == 'P') { - skipAugP(); - continue; - } - if (C == 'L') { - readByte(); - continue; - } - failOn(Aug.data(), "unknown .eh_frame augmentation string: " + Aug); - } - return DW_EH_PE_absptr; -} |
