bool DWARFFormValue::extractValue(const DWARFDataExtractor &Data, uint32_t *OffsetPtr, DWARFFormParams FP, const DWARFUnit *CU) { 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.getU64(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: 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_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 = reinterpret_cast<const uint8_t *>(Str.data()); *OffsetPtr += Value.uval; } } return true; }
bool DWARFDebugLine::LineTable::parse(DWARFDataExtractor &DebugLineData, uint32_t *OffsetPtr, const DWARFUnit *U, raw_ostream *OS) { const uint32_t DebugLineOffset = *OffsetPtr; clear(); if (!Prologue.parse(DebugLineData, OffsetPtr, U)) { // Restore our offset and return false to indicate failure! *OffsetPtr = DebugLineOffset; return false; } if (OS) Prologue.dump(*OS); const uint32_t EndOffset = DebugLineOffset + Prologue.TotalLength + Prologue.sizeofTotalLength(); // See if we should tell the data extractor the address size. if (DebugLineData.getAddressSize() == 0) DebugLineData.setAddressSize(Prologue.getAddressSize()); else assert(Prologue.getAddressSize() == 0 || Prologue.getAddressSize() == DebugLineData.getAddressSize()); ParsingState State(this); while (*OffsetPtr < EndOffset) { if (OS) *OS << format("0x%08.08" PRIx32 ": ", *OffsetPtr); uint8_t Opcode = DebugLineData.getU8(OffsetPtr); if (OS) *OS << format("%02.02" PRIx8 " ", Opcode); if (Opcode == 0) { // Extended Opcodes always start with a zero opcode followed by // a uleb128 length so you can skip ones you don't know about uint64_t Len = DebugLineData.getULEB128(OffsetPtr); uint32_t ExtOffset = *OffsetPtr; // Tolerate zero-length; assume length is correct and soldier on. if (Len == 0) { if (OS) *OS << "Badly formed extended line op (length 0)\n"; continue; } uint8_t SubOpcode = DebugLineData.getU8(OffsetPtr); if (OS) *OS << LNExtendedString(SubOpcode); switch (SubOpcode) { case DW_LNE_end_sequence: // Set the end_sequence register of the state machine to true and // append a row to the matrix using the current values of the // state-machine registers. Then reset the registers to the initial // values specified above. Every statement program sequence must end // with a DW_LNE_end_sequence instruction which creates a row whose // address is that of the byte after the last target machine instruction // of the sequence. State.Row.EndSequence = true; State.appendRowToMatrix(*OffsetPtr); if (OS) { *OS << "\n"; OS->indent(12); State.Row.dump(*OS); } State.resetRowAndSequence(); break; case DW_LNE_set_address: // Takes a single relocatable address as an operand. The size of the // operand is the size appropriate to hold an address on the target // machine. Set the address register to the value given by the // relocatable address. All of the other statement program opcodes // that affect the address register add a delta to it. This instruction // stores a relocatable value into it instead. // // Make sure the extractor knows the address size. If not, infer it // from the size of the operand. if (DebugLineData.getAddressSize() == 0) DebugLineData.setAddressSize(Len - 1); else assert(DebugLineData.getAddressSize() == Len - 1); State.Row.Address = DebugLineData.getRelocatedAddress(OffsetPtr); if (OS) *OS << format(" (0x%16.16" PRIx64 ")", State.Row.Address); break; case DW_LNE_define_file: // Takes 4 arguments. The first is a null terminated string containing // a source file name. The second is an unsigned LEB128 number // representing the directory index of the directory in which the file // was found. The third is an unsigned LEB128 number representing the // time of last modification of the file. The fourth is an unsigned // LEB128 number representing the length in bytes of the file. The time // and length fields may contain LEB128(0) if the information is not // available. // // The directory index represents an entry in the include_directories // section of the statement program prologue. The index is LEB128(0) // if the file was found in the current directory of the compilation, // LEB128(1) if it was found in the first directory in the // include_directories section, and so on. The directory index is // ignored for file names that represent full path names. // // The files are numbered, starting at 1, in the order in which they // appear; the names in the prologue come before names defined by // the DW_LNE_define_file instruction. These numbers are used in the // the file register of the state machine. { FileNameEntry FileEntry; FileEntry.Name = DebugLineData.getCStr(OffsetPtr); FileEntry.DirIdx = DebugLineData.getULEB128(OffsetPtr); FileEntry.ModTime = DebugLineData.getULEB128(OffsetPtr); FileEntry.Length = DebugLineData.getULEB128(OffsetPtr); Prologue.FileNames.push_back(FileEntry); if (OS) *OS << " (" << FileEntry.Name.str() << ", dir=" << FileEntry.DirIdx << ", mod_time=" << format("(0x%16.16" PRIx64 ")", FileEntry.ModTime) << ", length=" << FileEntry.Length << ")"; } break; case DW_LNE_set_discriminator: State.Row.Discriminator = DebugLineData.getULEB128(OffsetPtr); if (OS) *OS << " (" << State.Row.Discriminator << ")"; break; default: if (OS) *OS << format("Unrecognized extended op 0x%02.02" PRIx8, SubOpcode) << format(" length %" PRIx64, Len); // Len doesn't include the zero opcode byte or the length itself, but // it does include the sub_opcode, so we have to adjust for that. (*OffsetPtr) += Len - 1; break; } // Make sure the stated and parsed lengths are the same. // Otherwise we have an unparseable line-number program. if (*OffsetPtr - ExtOffset != Len) { fprintf(stderr, "Unexpected line op length at offset 0x%8.8" PRIx32 " expected 0x%2.2" PRIx64 " found 0x%2.2" PRIx32 "\n", ExtOffset, Len, *OffsetPtr - ExtOffset); // Skip the rest of the line-number program. *OffsetPtr = EndOffset; return false; } } else if (Opcode < Prologue.OpcodeBase) { if (OS) *OS << LNStandardString(Opcode); switch (Opcode) { // Standard Opcodes case DW_LNS_copy: // Takes no arguments. Append a row to the matrix using the // current values of the state-machine registers. Then set // the basic_block register to false. State.appendRowToMatrix(*OffsetPtr); if (OS) { *OS << "\n"; OS->indent(12); State.Row.dump(*OS); *OS << "\n"; } break; case DW_LNS_advance_pc: // Takes a single unsigned LEB128 operand, multiplies it by the // min_inst_length field of the prologue, and adds the // result to the address register of the state machine. { uint64_t AddrOffset = DebugLineData.getULEB128(OffsetPtr) * Prologue.MinInstLength; State.Row.Address += AddrOffset; if (OS) *OS << " (" << AddrOffset << ")"; } break; case DW_LNS_advance_line: // Takes a single signed LEB128 operand and adds that value to // the line register of the state machine. State.Row.Line += DebugLineData.getSLEB128(OffsetPtr); if (OS) *OS << " (" << State.Row.Line << ")"; break; case DW_LNS_set_file: // Takes a single unsigned LEB128 operand and stores it in the file // register of the state machine. State.Row.File = DebugLineData.getULEB128(OffsetPtr); if (OS) *OS << " (" << State.Row.File << ")"; break; case DW_LNS_set_column: // Takes a single unsigned LEB128 operand and stores it in the // column register of the state machine. State.Row.Column = DebugLineData.getULEB128(OffsetPtr); if (OS) *OS << " (" << State.Row.Column << ")"; break; case DW_LNS_negate_stmt: // Takes no arguments. Set the is_stmt register of the state // machine to the logical negation of its current value. State.Row.IsStmt = !State.Row.IsStmt; break; case DW_LNS_set_basic_block: // Takes no arguments. Set the basic_block register of the // state machine to true State.Row.BasicBlock = true; break; case DW_LNS_const_add_pc: // Takes no arguments. Add to the address register of the state // machine the address increment value corresponding to special // opcode 255. The motivation for DW_LNS_const_add_pc is this: // when the statement program needs to advance the address by a // small amount, it can use a single special opcode, which occupies // a single byte. When it needs to advance the address by up to // twice the range of the last special opcode, it can use // DW_LNS_const_add_pc followed by a special opcode, for a total // of two bytes. Only if it needs to advance the address by more // than twice that range will it need to use both DW_LNS_advance_pc // and a special opcode, requiring three or more bytes. { uint8_t AdjustOpcode = 255 - Prologue.OpcodeBase; uint64_t AddrOffset = (AdjustOpcode / Prologue.LineRange) * Prologue.MinInstLength; State.Row.Address += AddrOffset; if (OS) *OS << format(" (0x%16.16" PRIx64 ")", AddrOffset); } break; case DW_LNS_fixed_advance_pc: // Takes a single uhalf operand. Add to the address register of // the state machine the value of the (unencoded) operand. This // is the only extended opcode that takes an argument that is not // a variable length number. The motivation for DW_LNS_fixed_advance_pc // is this: existing assemblers cannot emit DW_LNS_advance_pc or // special opcodes because they cannot encode LEB128 numbers or // judge when the computation of a special opcode overflows and // requires the use of DW_LNS_advance_pc. Such assemblers, however, // can use DW_LNS_fixed_advance_pc instead, sacrificing compression. { uint16_t PCOffset = DebugLineData.getU16(OffsetPtr); State.Row.Address += PCOffset; if (OS) *OS << format(" (0x%16.16" PRIx64 ")", PCOffset); } break; case DW_LNS_set_prologue_end: // Takes no arguments. Set the prologue_end register of the // state machine to true State.Row.PrologueEnd = true; break; case DW_LNS_set_epilogue_begin: // Takes no arguments. Set the basic_block register of the // state machine to true State.Row.EpilogueBegin = true; break; case DW_LNS_set_isa: // Takes a single unsigned LEB128 operand and stores it in the // column register of the state machine. State.Row.Isa = DebugLineData.getULEB128(OffsetPtr); if (OS) *OS << " (" << State.Row.Isa << ")"; break; default: // Handle any unknown standard opcodes here. We know the lengths // of such opcodes because they are specified in the prologue // as a multiple of LEB128 operands for each opcode. { assert(Opcode - 1U < Prologue.StandardOpcodeLengths.size()); uint8_t OpcodeLength = Prologue.StandardOpcodeLengths[Opcode - 1]; for (uint8_t I = 0; I < OpcodeLength; ++I) { uint64_t Value = DebugLineData.getULEB128(OffsetPtr); if (OS) *OS << format("Skipping ULEB128 value: 0x%16.16" PRIx64 ")\n", Value); } } break; } } else { // Special Opcodes // A special opcode value is chosen based on the amount that needs // to be added to the line and address registers. The maximum line // increment for a special opcode is the value of the line_base // field in the header, plus the value of the line_range field, // minus 1 (line base + line range - 1). If the desired line // increment is greater than the maximum line increment, a standard // opcode must be used instead of a special opcode. The "address // advance" is calculated by dividing the desired address increment // by the minimum_instruction_length field from the header. The // special opcode is then calculated using the following formula: // // opcode = (desired line increment - line_base) + // (line_range * address advance) + opcode_base // // If the resulting opcode is greater than 255, a standard opcode // must be used instead. // // To decode a special opcode, subtract the opcode_base from the // opcode itself to give the adjusted opcode. The amount to // increment the address register is the result of the adjusted // opcode divided by the line_range multiplied by the // minimum_instruction_length field from the header. That is: // // address increment = (adjusted opcode / line_range) * // minimum_instruction_length // // The amount to increment the line register is the line_base plus // the result of the adjusted opcode modulo the line_range. That is: // // line increment = line_base + (adjusted opcode % line_range) uint8_t AdjustOpcode = Opcode - Prologue.OpcodeBase; uint64_t AddrOffset = (AdjustOpcode / Prologue.LineRange) * Prologue.MinInstLength; int32_t LineOffset = Prologue.LineBase + (AdjustOpcode % Prologue.LineRange); State.Row.Line += LineOffset; State.Row.Address += AddrOffset; if (OS) { *OS << "address += " << ((uint32_t)AdjustOpcode) << ", line += " << LineOffset << "\n"; OS->indent(12); State.Row.dump(*OS); } State.appendRowToMatrix(*OffsetPtr); // Reset discriminator to 0. State.Row.Discriminator = 0; } if(OS) *OS << "\n"; } if (!State.Sequence.Empty) { fprintf(stderr, "warning: last sequence in debug line table is not" "terminated!\n"); } // Sort all sequences so that address lookup will work faster. if (!Sequences.empty()) { std::sort(Sequences.begin(), Sequences.end(), Sequence::orderByLowPC); // Note: actually, instruction address ranges of sequences should not // overlap (in shared objects and executables). If they do, the address // lookup would still work, though, but result would be ambiguous. // We don't report warning in this case. For example, // sometimes .so compiled from multiple object files contains a few // rudimentary sequences for address ranges [0x0, 0xsomething). } return EndOffset; }