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FrameEntry doesn't need to hold a reference to the section it is located in. Instead, pass DataExtractor as an argument of parsing function. No functionality change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207461 91177308-0d34-0410-b5e6-96231b3b80d8
374 lines
12 KiB
C++
374 lines
12 KiB
C++
//===-- DWARFDebugFrame.h - Parsing of .debug_frame -------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "DWARFDebugFrame.h"
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#include "llvm/ADT/SmallString.h"
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#include "llvm/Support/DataTypes.h"
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#include "llvm/Support/Dwarf.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/Format.h"
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#include "llvm/Support/raw_ostream.h"
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#include <string>
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#include <vector>
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using namespace llvm;
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using namespace dwarf;
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/// \brief Abstract frame entry defining the common interface concrete
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/// entries implement.
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class llvm::FrameEntry {
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public:
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enum FrameKind {FK_CIE, FK_FDE};
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FrameEntry(FrameKind K, uint64_t Offset, uint64_t Length)
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: Kind(K), Offset(Offset), Length(Length) {}
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virtual ~FrameEntry() {
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}
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FrameKind getKind() const { return Kind; }
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virtual uint64_t getOffset() const { return Offset; }
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/// \brief Parse and store a sequence of CFI instructions from Data,
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/// starting at *Offset and ending at EndOffset. If everything
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/// goes well, *Offset should be equal to EndOffset when this method
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/// returns. Otherwise, an error occurred.
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virtual void parseInstructions(DataExtractor Data, uint32_t *Offset,
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uint32_t EndOffset);
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/// \brief Dump the entry header to the given output stream.
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virtual void dumpHeader(raw_ostream &OS) const = 0;
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/// \brief Dump the entry's instructions to the given output stream.
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virtual void dumpInstructions(raw_ostream &OS) const;
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protected:
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const FrameKind Kind;
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/// \brief Offset of this entry in the section.
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uint64_t Offset;
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/// \brief Entry length as specified in DWARF.
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uint64_t Length;
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/// An entry may contain CFI instructions. An instruction consists of an
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/// opcode and an optional sequence of operands.
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typedef std::vector<uint64_t> Operands;
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struct Instruction {
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Instruction(uint8_t Opcode)
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: Opcode(Opcode)
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{}
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uint8_t Opcode;
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Operands Ops;
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};
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std::vector<Instruction> Instructions;
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/// Convenience methods to add a new instruction with the given opcode and
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/// operands to the Instructions vector.
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void addInstruction(uint8_t Opcode) {
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Instructions.push_back(Instruction(Opcode));
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}
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void addInstruction(uint8_t Opcode, uint64_t Operand1) {
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Instructions.push_back(Instruction(Opcode));
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Instructions.back().Ops.push_back(Operand1);
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}
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void addInstruction(uint8_t Opcode, uint64_t Operand1, uint64_t Operand2) {
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Instructions.push_back(Instruction(Opcode));
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Instructions.back().Ops.push_back(Operand1);
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Instructions.back().Ops.push_back(Operand2);
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}
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};
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// See DWARF standard v3, section 7.23
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const uint8_t DWARF_CFI_PRIMARY_OPCODE_MASK = 0xc0;
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const uint8_t DWARF_CFI_PRIMARY_OPERAND_MASK = 0x3f;
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void FrameEntry::parseInstructions(DataExtractor Data, uint32_t *Offset,
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uint32_t EndOffset) {
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while (*Offset < EndOffset) {
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uint8_t Opcode = Data.getU8(Offset);
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// Some instructions have a primary opcode encoded in the top bits.
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uint8_t Primary = Opcode & DWARF_CFI_PRIMARY_OPCODE_MASK;
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if (Primary) {
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// If it's a primary opcode, the first operand is encoded in the bottom
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// bits of the opcode itself.
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uint64_t Op1 = Opcode & DWARF_CFI_PRIMARY_OPERAND_MASK;
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switch (Primary) {
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default: llvm_unreachable("Impossible primary CFI opcode");
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case DW_CFA_advance_loc:
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case DW_CFA_restore:
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addInstruction(Primary, Op1);
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break;
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case DW_CFA_offset:
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addInstruction(Primary, Op1, Data.getULEB128(Offset));
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break;
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}
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} else {
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// Extended opcode - its value is Opcode itself.
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switch (Opcode) {
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default: llvm_unreachable("Invalid extended CFI opcode");
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case DW_CFA_nop:
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case DW_CFA_remember_state:
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case DW_CFA_restore_state:
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case DW_CFA_GNU_window_save:
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// No operands
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addInstruction(Opcode);
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break;
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case DW_CFA_set_loc:
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// Operands: Address
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addInstruction(Opcode, Data.getAddress(Offset));
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break;
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case DW_CFA_advance_loc1:
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// Operands: 1-byte delta
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addInstruction(Opcode, Data.getU8(Offset));
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break;
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case DW_CFA_advance_loc2:
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// Operands: 2-byte delta
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addInstruction(Opcode, Data.getU16(Offset));
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break;
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case DW_CFA_advance_loc4:
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// Operands: 4-byte delta
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addInstruction(Opcode, Data.getU32(Offset));
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break;
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case DW_CFA_restore_extended:
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case DW_CFA_undefined:
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case DW_CFA_same_value:
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case DW_CFA_def_cfa_register:
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case DW_CFA_def_cfa_offset:
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// Operands: ULEB128
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addInstruction(Opcode, Data.getULEB128(Offset));
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break;
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case DW_CFA_def_cfa_offset_sf:
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// Operands: SLEB128
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addInstruction(Opcode, Data.getSLEB128(Offset));
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break;
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case DW_CFA_offset_extended:
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case DW_CFA_register:
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case DW_CFA_def_cfa:
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case DW_CFA_val_offset:
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// Operands: ULEB128, ULEB128
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addInstruction(Opcode, Data.getULEB128(Offset),
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Data.getULEB128(Offset));
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break;
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case DW_CFA_offset_extended_sf:
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case DW_CFA_def_cfa_sf:
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case DW_CFA_val_offset_sf:
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// Operands: ULEB128, SLEB128
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addInstruction(Opcode, Data.getULEB128(Offset),
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Data.getSLEB128(Offset));
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break;
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case DW_CFA_def_cfa_expression:
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case DW_CFA_expression:
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case DW_CFA_val_expression:
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// TODO: implement this
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report_fatal_error("Values with expressions not implemented yet!");
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}
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}
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}
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}
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void FrameEntry::dumpInstructions(raw_ostream &OS) const {
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// TODO: at the moment only instruction names are dumped. Expand this to
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// dump operands as well.
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for (const auto &Instr : Instructions) {
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uint8_t Opcode = Instr.Opcode;
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if (Opcode & DWARF_CFI_PRIMARY_OPCODE_MASK)
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Opcode &= DWARF_CFI_PRIMARY_OPCODE_MASK;
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OS << " " << CallFrameString(Opcode) << ":\n";
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}
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}
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namespace {
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/// \brief DWARF Common Information Entry (CIE)
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class CIE : public FrameEntry {
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public:
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// CIEs (and FDEs) are simply container classes, so the only sensible way to
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// create them is by providing the full parsed contents in the constructor.
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CIE(uint64_t Offset, uint64_t Length, uint8_t Version,
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SmallString<8> Augmentation, uint64_t CodeAlignmentFactor,
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int64_t DataAlignmentFactor, uint64_t ReturnAddressRegister)
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: FrameEntry(FK_CIE, Offset, Length), Version(Version),
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Augmentation(Augmentation), CodeAlignmentFactor(CodeAlignmentFactor),
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DataAlignmentFactor(DataAlignmentFactor),
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ReturnAddressRegister(ReturnAddressRegister) {}
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~CIE() {
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}
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void dumpHeader(raw_ostream &OS) const override {
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OS << format("%08x %08x %08x CIE",
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(uint32_t)Offset, (uint32_t)Length, DW_CIE_ID)
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<< "\n";
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OS << format(" Version: %d\n", Version);
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OS << " Augmentation: \"" << Augmentation << "\"\n";
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OS << format(" Code alignment factor: %u\n",
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(uint32_t)CodeAlignmentFactor);
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OS << format(" Data alignment factor: %d\n",
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(int32_t)DataAlignmentFactor);
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OS << format(" Return address column: %d\n",
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(int32_t)ReturnAddressRegister);
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OS << "\n";
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}
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static bool classof(const FrameEntry *FE) {
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return FE->getKind() == FK_CIE;
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}
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private:
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/// The following fields are defined in section 6.4.1 of the DWARF standard v3
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uint8_t Version;
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SmallString<8> Augmentation;
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uint64_t CodeAlignmentFactor;
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int64_t DataAlignmentFactor;
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uint64_t ReturnAddressRegister;
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};
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/// \brief DWARF Frame Description Entry (FDE)
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class FDE : public FrameEntry {
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public:
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// Each FDE has a CIE it's "linked to". Our FDE contains is constructed with
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// an offset to the CIE (provided by parsing the FDE header). The CIE itself
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// is obtained lazily once it's actually required.
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FDE(uint64_t Offset, uint64_t Length, int64_t LinkedCIEOffset,
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uint64_t InitialLocation, uint64_t AddressRange)
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: FrameEntry(FK_FDE, Offset, Length), LinkedCIEOffset(LinkedCIEOffset),
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InitialLocation(InitialLocation), AddressRange(AddressRange),
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LinkedCIE(nullptr) {}
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~FDE() {
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}
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void dumpHeader(raw_ostream &OS) const override {
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OS << format("%08x %08x %08x FDE ",
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(uint32_t)Offset, (uint32_t)Length, (int32_t)LinkedCIEOffset);
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OS << format("cie=%08x pc=%08x...%08x\n",
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(int32_t)LinkedCIEOffset,
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(uint32_t)InitialLocation,
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(uint32_t)InitialLocation + (uint32_t)AddressRange);
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if (LinkedCIE) {
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OS << format("%p\n", LinkedCIE);
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}
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}
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static bool classof(const FrameEntry *FE) {
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return FE->getKind() == FK_FDE;
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}
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private:
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/// The following fields are defined in section 6.4.1 of the DWARF standard v3
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uint64_t LinkedCIEOffset;
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uint64_t InitialLocation;
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uint64_t AddressRange;
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CIE *LinkedCIE;
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};
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} // end anonymous namespace
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DWARFDebugFrame::DWARFDebugFrame() {
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}
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DWARFDebugFrame::~DWARFDebugFrame() {
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}
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static void LLVM_ATTRIBUTE_UNUSED dumpDataAux(DataExtractor Data,
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uint32_t Offset, int Length) {
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errs() << "DUMP: ";
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for (int i = 0; i < Length; ++i) {
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uint8_t c = Data.getU8(&Offset);
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errs().write_hex(c); errs() << " ";
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}
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errs() << "\n";
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}
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void DWARFDebugFrame::parse(DataExtractor Data) {
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uint32_t Offset = 0;
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while (Data.isValidOffset(Offset)) {
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uint32_t StartOffset = Offset;
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bool IsDWARF64 = false;
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uint64_t Length = Data.getU32(&Offset);
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uint64_t Id;
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if (Length == UINT32_MAX) {
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// DWARF-64 is distinguished by the first 32 bits of the initial length
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// field being 0xffffffff. Then, the next 64 bits are the actual entry
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// length.
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IsDWARF64 = true;
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Length = Data.getU64(&Offset);
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}
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// At this point, Offset points to the next field after Length.
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// Length is the structure size excluding itself. Compute an offset one
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// past the end of the structure (needed to know how many instructions to
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// read).
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// TODO: For honest DWARF64 support, DataExtractor will have to treat
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// offset_ptr as uint64_t*
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uint32_t EndStructureOffset = Offset + static_cast<uint32_t>(Length);
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// The Id field's size depends on the DWARF format
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Id = Data.getUnsigned(&Offset, IsDWARF64 ? 8 : 4);
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bool IsCIE = ((IsDWARF64 && Id == DW64_CIE_ID) || Id == DW_CIE_ID);
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if (IsCIE) {
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// Note: this is specifically DWARFv3 CIE header structure. It was
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// changed in DWARFv4. We currently don't support reading DWARFv4
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// here because LLVM itself does not emit it (and LLDB doesn't
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// support it either).
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uint8_t Version = Data.getU8(&Offset);
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const char *Augmentation = Data.getCStr(&Offset);
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uint64_t CodeAlignmentFactor = Data.getULEB128(&Offset);
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int64_t DataAlignmentFactor = Data.getSLEB128(&Offset);
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uint64_t ReturnAddressRegister = Data.getULEB128(&Offset);
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Entries.emplace_back(new CIE(StartOffset, Length, Version,
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StringRef(Augmentation), CodeAlignmentFactor,
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DataAlignmentFactor, ReturnAddressRegister));
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} else {
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// FDE
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uint64_t CIEPointer = Id;
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uint64_t InitialLocation = Data.getAddress(&Offset);
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uint64_t AddressRange = Data.getAddress(&Offset);
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Entries.emplace_back(new FDE(StartOffset, Length, CIEPointer,
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InitialLocation, AddressRange));
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}
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Entries.back()->parseInstructions(Data, &Offset, EndStructureOffset);
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if (Offset != EndStructureOffset) {
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std::string Str;
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raw_string_ostream OS(Str);
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OS << format("Parsing entry instructions at %lx failed", StartOffset);
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report_fatal_error(Str);
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}
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}
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}
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void DWARFDebugFrame::dump(raw_ostream &OS) const {
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OS << "\n";
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for (const auto &Entry : Entries) {
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Entry->dumpHeader(OS);
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Entry->dumpInstructions(OS);
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OS << "\n";
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}
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}
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