X-Git-Url: http://git.ipfire.org/?a=blobdiff_plain;f=gold%2Fdwarf_reader.cc;h=78111397d3136aa6a8103071e70365a11c398651;hb=d87bef3a7bc827fa36a69d2c334aa82f7d188d81;hp=1873091b4973ab2ba0d45b89bdb33d083dfc72f5;hpb=338f2eba1ad8e08b031986d6a517c6ff53f556cd;p=thirdparty%2Fbinutils-gdb.git diff --git a/gold/dwarf_reader.cc b/gold/dwarf_reader.cc index 1873091b497..78111397d31 100644 --- a/gold/dwarf_reader.cc +++ b/gold/dwarf_reader.cc @@ -1,6 +1,6 @@ // dwarf_reader.cc -- parse dwarf2/3 debug information -// Copyright 2007 Free Software Foundation, Inc. +// Copyright (C) 2007-2023 Free Software Foundation, Inc. // Written by Ian Lance Taylor . // This file is part of gold. @@ -22,72 +22,1751 @@ #include "gold.h" +#include +#include +#include + +#include "debug.h" #include "elfcpp_swap.h" #include "dwarf.h" +#include "object.h" +#include "reloc.h" #include "dwarf_reader.h" +#include "int_encoding.h" +#include "compressed_output.h" + +namespace gold { -namespace { +// Class Sized_elf_reloc_mapper -// Read an unsigned LEB128 number. Each byte contains 7 bits of -// information, plus one bit saying whether the number continues or -// not. +// Initialize the relocation tracker for section RELOC_SHNDX. -uint64_t -read_unsigned_LEB_128(const unsigned char* buffer, size_t* len) +template +bool +Sized_elf_reloc_mapper::do_initialize( + unsigned int reloc_shndx, unsigned int reloc_type) +{ + this->reloc_type_ = reloc_type; + return this->track_relocs_.initialize(this->object_, reloc_shndx, + reloc_type); +} + +// Looks in the symtab to see what section a symbol is in. + +template +unsigned int +Sized_elf_reloc_mapper::symbol_section( + unsigned int symndx, Address* value, bool* is_ordinary) { - uint64_t result = 0; - size_t num_read = 0; - unsigned int shift = 0; - unsigned char byte; + const int symsize = elfcpp::Elf_sizes::sym_size; + gold_assert(static_cast((symndx + 1) * symsize) <= this->symtab_size_); + elfcpp::Sym elfsym(this->symtab_ + symndx * symsize); + *value = elfsym.get_st_value(); + return this->object_->adjust_sym_shndx(symndx, elfsym.get_st_shndx(), + is_ordinary); +} - do +// Return the section index and offset within the section of +// the target of the relocation for RELOC_OFFSET. + +template +unsigned int +Sized_elf_reloc_mapper::do_get_reloc_target( + off_t reloc_offset, off_t* target_offset) +{ + this->track_relocs_.advance(reloc_offset); + if (reloc_offset != this->track_relocs_.next_offset()) + return 0; + unsigned int symndx = this->track_relocs_.next_symndx(); + typename elfcpp::Elf_types::Elf_Addr value; + bool is_ordinary; + unsigned int target_shndx = this->symbol_section(symndx, &value, + &is_ordinary); + if (!is_ordinary) + return 0; + if (this->reloc_type_ == elfcpp::SHT_RELA) + value += this->track_relocs_.next_addend(); + *target_offset = value; + return target_shndx; +} + +static inline Elf_reloc_mapper* +make_elf_reloc_mapper(Relobj* object, const unsigned char* symtab, + off_t symtab_size) +{ + if (object->elfsize() == 32) { - byte = *buffer++; - num_read++; - result |= (static_cast(byte & 0x7f)) << shift; - shift += 7; + if (object->is_big_endian()) + { +#ifdef HAVE_TARGET_32_BIG + return new Sized_elf_reloc_mapper<32, true>(object, symtab, + symtab_size); +#else + gold_unreachable(); +#endif + } + else + { +#ifdef HAVE_TARGET_32_LITTLE + return new Sized_elf_reloc_mapper<32, false>(object, symtab, + symtab_size); +#else + gold_unreachable(); +#endif + } } - while (byte & 0x80); + else if (object->elfsize() == 64) + { + if (object->is_big_endian()) + { +#ifdef HAVE_TARGET_64_BIG + return new Sized_elf_reloc_mapper<64, true>(object, symtab, + symtab_size); +#else + gold_unreachable(); +#endif + } + else + { +#ifdef HAVE_TARGET_64_LITTLE + return new Sized_elf_reloc_mapper<64, false>(object, symtab, + symtab_size); +#else + gold_unreachable(); +#endif + } + } + else + gold_unreachable(); +} - *len = num_read; +// class Dwarf_abbrev_table - return result; +void +Dwarf_abbrev_table::clear_abbrev_codes() +{ + for (unsigned int code = 0; code < this->low_abbrev_code_max_; ++code) + { + if (this->low_abbrev_codes_[code] != NULL) + { + delete this->low_abbrev_codes_[code]; + this->low_abbrev_codes_[code] = NULL; + } + } + for (Abbrev_code_table::iterator it = this->high_abbrev_codes_.begin(); + it != this->high_abbrev_codes_.end(); + ++it) + { + if (it->second != NULL) + delete it->second; + } + this->high_abbrev_codes_.clear(); +} + +// Read the abbrev table from an object file. + +bool +Dwarf_abbrev_table::do_read_abbrevs( + Relobj* object, + unsigned int abbrev_shndx, + off_t abbrev_offset) +{ + this->clear_abbrev_codes(); + + // If we don't have relocations, abbrev_shndx will be 0, and + // we'll have to hunt for the .debug_abbrev section. + if (abbrev_shndx == 0 && this->abbrev_shndx_ > 0) + abbrev_shndx = this->abbrev_shndx_; + else if (abbrev_shndx == 0) + { + for (unsigned int i = 1; i < object->shnum(); ++i) + { + std::string name = object->section_name(i); + if (name == ".debug_abbrev" || name == ".zdebug_abbrev") + { + abbrev_shndx = i; + // Correct the offset. For incremental update links, we have a + // relocated offset that is relative to the output section, but + // here we need an offset relative to the input section. + abbrev_offset -= object->output_section_offset(i); + break; + } + } + if (abbrev_shndx == 0) + return false; + } + + // Get the section contents and decompress if necessary. + if (abbrev_shndx != this->abbrev_shndx_) + { + if (this->owns_buffer_ && this->buffer_ != NULL) + { + delete[] this->buffer_; + this->owns_buffer_ = false; + } + + section_size_type buffer_size; + this->buffer_ = + object->decompressed_section_contents(abbrev_shndx, + &buffer_size, + &this->owns_buffer_); + this->buffer_end_ = this->buffer_ + buffer_size; + this->abbrev_shndx_ = abbrev_shndx; + } + + this->buffer_pos_ = this->buffer_ + abbrev_offset; + return true; } -// Read a signed LEB128 number. These are like regular LEB128 -// numbers, except the last byte may have a sign bit set. +// Lookup the abbrev code entry for CODE. This function is called +// only when the abbrev code is not in the direct lookup table. +// It may be in the hash table, it may not have been read yet, +// or it may not exist in the abbrev table. + +const Dwarf_abbrev_table::Abbrev_code* +Dwarf_abbrev_table::do_get_abbrev(unsigned int code) +{ + // See if the abbrev code is already in the hash table. + Abbrev_code_table::const_iterator it = this->high_abbrev_codes_.find(code); + if (it != this->high_abbrev_codes_.end()) + return it->second; + + // Read and store abbrev code definitions until we find the + // one we're looking for. + for (;;) + { + // Read the abbrev code. A zero here indicates the end of the + // abbrev table. + size_t len; + if (this->buffer_pos_ >= this->buffer_end_) + return NULL; + uint64_t nextcode = read_unsigned_LEB_128(this->buffer_pos_, &len); + if (nextcode == 0) + { + this->buffer_pos_ = this->buffer_end_; + return NULL; + } + this->buffer_pos_ += len; + + // Read the tag. + if (this->buffer_pos_ >= this->buffer_end_) + return NULL; + uint64_t tag = read_unsigned_LEB_128(this->buffer_pos_, &len); + this->buffer_pos_ += len; + + // Read the has_children flag. + if (this->buffer_pos_ >= this->buffer_end_) + return NULL; + bool has_children = *this->buffer_pos_ == elfcpp::DW_CHILDREN_yes; + this->buffer_pos_ += 1; + + // Read the list of (attribute, form) pairs. + Abbrev_code* entry = new Abbrev_code(tag, has_children); + for (;;) + { + // Read the attribute. + if (this->buffer_pos_ >= this->buffer_end_) + return NULL; + uint64_t attr = read_unsigned_LEB_128(this->buffer_pos_, &len); + this->buffer_pos_ += len; + + // Read the form. + if (this->buffer_pos_ >= this->buffer_end_) + return NULL; + uint64_t form = read_unsigned_LEB_128(this->buffer_pos_, &len); + this->buffer_pos_ += len; + + // For DW_FORM_implicit_const, read the constant. + int64_t implicit_const = 0; + if (form == elfcpp::DW_FORM_implicit_const) + { + implicit_const = read_signed_LEB_128(this->buffer_pos_, &len); + this->buffer_pos_ += len; + } + + // A (0,0) pair terminates the list. + if (attr == 0 && form == 0) + break; + + if (attr == elfcpp::DW_AT_sibling) + entry->has_sibling_attribute = true; + + entry->add_attribute(attr, form, implicit_const); + } + + this->store_abbrev(nextcode, entry); + if (nextcode == code) + return entry; + } + + return NULL; +} + +// class Dwarf_ranges_table + +// Read the ranges table from an object file. + +bool +Dwarf_ranges_table::read_ranges_table( + Relobj* object, + const unsigned char* symtab, + off_t symtab_size, + unsigned int ranges_shndx, + unsigned int version) +{ + const std::string section_name(version < 5 + ? ".debug_ranges" + : ".debug_rnglists"); + const std::string compressed_section_name(version < 5 + ? ".zdebug_ranges" + : ".zdebug_rnglists"); + + // If we've already read this abbrev table, return immediately. + if (this->ranges_shndx_ > 0 + && this->ranges_shndx_ == ranges_shndx) + return true; + + // If we don't have relocations, ranges_shndx will be 0, and + // we'll have to hunt for the .debug_ranges section. + if (ranges_shndx == 0 && this->ranges_shndx_ > 0) + ranges_shndx = this->ranges_shndx_; + else if (ranges_shndx == 0) + { + for (unsigned int i = 1; i < object->shnum(); ++i) + { + std::string name = object->section_name(i); + if (name == section_name || name == compressed_section_name) + { + ranges_shndx = i; + this->output_section_offset_ = object->output_section_offset(i); + break; + } + } + if (ranges_shndx == 0) + return false; + } + + // Get the section contents and decompress if necessary. + if (ranges_shndx != this->ranges_shndx_) + { + if (this->owns_ranges_buffer_ && this->ranges_buffer_ != NULL) + { + delete[] this->ranges_buffer_; + this->owns_ranges_buffer_ = false; + } + + section_size_type buffer_size; + this->ranges_buffer_ = + object->decompressed_section_contents(ranges_shndx, + &buffer_size, + &this->owns_ranges_buffer_); + this->ranges_buffer_end_ = this->ranges_buffer_ + buffer_size; + this->ranges_shndx_ = ranges_shndx; + } + + if (this->ranges_reloc_mapper_ != NULL) + { + delete this->ranges_reloc_mapper_; + this->ranges_reloc_mapper_ = NULL; + } + + // For incremental objects, we have no relocations. + if (object->is_incremental()) + return true; + + // Find the relocation section for ".debug_ranges". + unsigned int reloc_shndx = 0; + unsigned int reloc_type = 0; + for (unsigned int i = 0; i < object->shnum(); ++i) + { + reloc_type = object->section_type(i); + if ((reloc_type == elfcpp::SHT_REL + || reloc_type == elfcpp::SHT_RELA) + && object->section_info(i) == ranges_shndx) + { + reloc_shndx = i; + break; + } + } + + this->ranges_reloc_mapper_ = make_elf_reloc_mapper(object, symtab, + symtab_size); + this->ranges_reloc_mapper_->initialize(reloc_shndx, reloc_type); + this->reloc_type_ = reloc_type; + + return true; +} + +// Read a range list from section RANGES_SHNDX at offset RANGES_OFFSET. + +Dwarf_range_list* +Dwarf_ranges_table::read_range_list( + Relobj* object, + const unsigned char* symtab, + off_t symtab_size, + unsigned int addr_size, + unsigned int ranges_shndx, + off_t offset) +{ + Dwarf_range_list* ranges; + + if (!this->read_ranges_table(object, symtab, symtab_size, ranges_shndx, 4)) + return NULL; + + // Correct the offset. For incremental update links, we have a + // relocated offset that is relative to the output section, but + // here we need an offset relative to the input section. + offset -= this->output_section_offset_; + + // Read the range list at OFFSET. + ranges = new Dwarf_range_list(); + off_t base = 0; + for (; + this->ranges_buffer_ + offset < this->ranges_buffer_end_; + offset += 2 * addr_size) + { + off_t start; + off_t end; + + // Read the raw contents of the section. + if (addr_size == 4) + { + start = this->dwinfo_->read_from_pointer<32>(this->ranges_buffer_ + + offset); + end = this->dwinfo_->read_from_pointer<32>(this->ranges_buffer_ + + offset + 4); + } + else + { + start = this->dwinfo_->read_from_pointer<64>(this->ranges_buffer_ + + offset); + end = this->dwinfo_->read_from_pointer<64>(this->ranges_buffer_ + + offset + 8); + } + + // Check for relocations and adjust the values. + unsigned int shndx1 = 0; + unsigned int shndx2 = 0; + if (this->ranges_reloc_mapper_ != NULL) + { + shndx1 = this->lookup_reloc(offset, &start); + shndx2 = this->lookup_reloc(offset + addr_size, &end); + } + + // End of list is marked by a pair of zeroes. + if (shndx1 == 0 && start == 0 && end == 0) + break; + + // A "base address selection entry" is identified by + // 0xffffffff for the first value of the pair. The second + // value is used as a base for subsequent range list entries. + if (shndx1 == 0 && start == -1) + base = end; + else if (shndx1 == shndx2) + { + if (shndx1 == 0 || object->is_section_included(shndx1)) + ranges->add(shndx1, base + start, base + end); + } + else + gold_warning(_("%s: DWARF info may be corrupt; offsets in a " + "range list entry are in different sections"), + object->name().c_str()); + } + + return ranges; +} + +// Read a DWARF 5 range list from section RANGES_SHNDX at offset RANGES_OFFSET. + +Dwarf_range_list* +Dwarf_ranges_table::read_range_list_v5( + Relobj* object, + const unsigned char* symtab, + off_t symtab_size, + unsigned int addr_size, + unsigned int ranges_shndx, + off_t offset) +{ + Dwarf_range_list* ranges; + + if (!this->read_ranges_table(object, symtab, symtab_size, ranges_shndx, 5)) + return NULL; + + ranges = new Dwarf_range_list(); + off_t base = 0; + unsigned int shndx0 = 0; + + // Correct the offset. For incremental update links, we have a + // relocated offset that is relative to the output section, but + // here we need an offset relative to the input section. + offset -= this->output_section_offset_; + + // Read the range list at OFFSET. + const unsigned char* prle = this->ranges_buffer_ + offset; + while (prle < this->ranges_buffer_end_) + { + off_t start; + off_t end; + unsigned int shndx1 = 0; + unsigned int shndx2 = 0; + size_t len; + + // Read the entry type. + unsigned int rle_type = *prle++; + offset += 1; + + if (rle_type == elfcpp::DW_RLE_end_of_list) + break; + + switch (rle_type) + { + case elfcpp::DW_RLE_base_address: + if (addr_size == 4) + base = this->dwinfo_->read_from_pointer<32>(prle); + else + base = this->dwinfo_->read_from_pointer<64>(prle); + if (this->ranges_reloc_mapper_ != NULL) + shndx0 = this->lookup_reloc(offset, &base); + prle += addr_size; + offset += addr_size; + break; + + case elfcpp::DW_RLE_offset_pair: + start = read_unsigned_LEB_128(prle, &len); + prle += len; + offset += len; + end = read_unsigned_LEB_128(prle, &len); + prle += len; + offset += len; + if (shndx0 == 0 || object->is_section_included(shndx0)) + ranges->add(shndx0, base + start, base + end); + break; + + case elfcpp::DW_RLE_start_end: + if (addr_size == 4) + { + start = this->dwinfo_->read_from_pointer<32>(prle); + end = this->dwinfo_->read_from_pointer<32>(prle + 4); + } + else + { + start = this->dwinfo_->read_from_pointer<64>(prle); + end = this->dwinfo_->read_from_pointer<64>(prle + 8); + } + if (this->ranges_reloc_mapper_ != NULL) + { + shndx1 = this->lookup_reloc(offset, &start); + shndx2 = this->lookup_reloc(offset + addr_size, &end); + if (shndx1 != shndx2) + gold_warning(_("%s: DWARF info may be corrupt; offsets in a " + "range list entry are in different sections"), + object->name().c_str()); + } + prle += addr_size * 2; + offset += addr_size * 2; + if (shndx1 == 0 || object->is_section_included(shndx1)) + ranges->add(shndx1, start, end); + break; + + case elfcpp::DW_RLE_start_length: + if (addr_size == 4) + start = this->dwinfo_->read_from_pointer<32>(prle); + else + start = this->dwinfo_->read_from_pointer<64>(prle); + if (this->ranges_reloc_mapper_ != NULL) + shndx1 = this->lookup_reloc(offset, &start); + prle += addr_size; + offset += addr_size; + end = start + read_unsigned_LEB_128(prle, &len); + prle += len; + offset += len; + if (shndx1 == 0 || object->is_section_included(shndx1)) + ranges->add(shndx1, start, end); + break; + + default: + gold_warning(_("%s: DWARF range list contains " + "unsupported entry type (%d)"), + object->name().c_str(), rle_type); + break; + } + } + + return ranges; +} + +// Look for a relocation at offset OFF in the range table, +// and return the section index and offset of the target. + +unsigned int +Dwarf_ranges_table::lookup_reloc(off_t off, off_t* target_off) +{ + off_t value; + unsigned int shndx = + this->ranges_reloc_mapper_->get_reloc_target(off, &value); + if (shndx == 0) + return 0; + if (this->reloc_type_ == elfcpp::SHT_REL) + *target_off += value; + else + *target_off = value; + return shndx; +} + +// class Dwarf_pubnames_table + +// Read the pubnames section from the object file. + +bool +Dwarf_pubnames_table::read_section(Relobj* object, const unsigned char* symtab, + off_t symtab_size) +{ + section_size_type buffer_size; + unsigned int shndx = 0; + const char* name = this->is_pubtypes_ ? "pubtypes" : "pubnames"; + const char* gnu_name = (this->is_pubtypes_ + ? "gnu_pubtypes" + : "gnu_pubnames"); + + for (unsigned int i = 1; i < object->shnum(); ++i) + { + std::string section_name = object->section_name(i); + const char* section_name_suffix = section_name.c_str(); + if (is_prefix_of(".debug_", section_name_suffix)) + section_name_suffix += 7; + else if (is_prefix_of(".zdebug_", section_name_suffix)) + section_name_suffix += 8; + else + continue; + if (strcmp(section_name_suffix, name) == 0) + { + shndx = i; + break; + } + else if (strcmp(section_name_suffix, gnu_name) == 0) + { + shndx = i; + this->is_gnu_style_ = true; + break; + } + } + if (shndx == 0) + return false; + + this->buffer_ = object->decompressed_section_contents(shndx, + &buffer_size, + &this->owns_buffer_); + if (this->buffer_ == NULL) + return false; + this->buffer_end_ = this->buffer_ + buffer_size; + + // For incremental objects, we have no relocations. + if (object->is_incremental()) + return true; + + // Find the relocation section + unsigned int reloc_shndx = 0; + unsigned int reloc_type = 0; + for (unsigned int i = 0; i < object->shnum(); ++i) + { + reloc_type = object->section_type(i); + if ((reloc_type == elfcpp::SHT_REL + || reloc_type == elfcpp::SHT_RELA) + && object->section_info(i) == shndx) + { + reloc_shndx = i; + break; + } + } + + this->reloc_mapper_ = make_elf_reloc_mapper(object, symtab, symtab_size); + this->reloc_mapper_->initialize(reloc_shndx, reloc_type); + this->reloc_type_ = reloc_type; + + return true; +} + +// Read the header for the set at OFFSET. + +bool +Dwarf_pubnames_table::read_header(off_t offset) +{ + // Make sure we have actually read the section. + gold_assert(this->buffer_ != NULL); + + if (offset < 0 || offset + 14 >= this->buffer_end_ - this->buffer_) + return false; + + const unsigned char* pinfo = this->buffer_ + offset; + + // Read the unit_length field. + uint64_t unit_length = this->dwinfo_->read_from_pointer<32>(pinfo); + pinfo += 4; + if (unit_length == 0xffffffff) + { + unit_length = this->dwinfo_->read_from_pointer<64>(pinfo); + this->unit_length_ = unit_length + 12; + pinfo += 8; + this->offset_size_ = 8; + } + else + { + this->unit_length_ = unit_length + 4; + this->offset_size_ = 4; + } + this->end_of_table_ = pinfo + unit_length; + + // If unit_length is too big, maybe we should reject the whole table, + // but in cases we know about, it seems OK to assume that the table + // is valid through the actual end of the section. + if (this->end_of_table_ > this->buffer_end_) + this->end_of_table_ = this->buffer_end_; + + // Check the version. + unsigned int version = this->dwinfo_->read_from_pointer<16>(pinfo); + pinfo += 2; + if (version != 2) + return false; + + this->reloc_mapper_->get_reloc_target(pinfo - this->buffer_, + &this->cu_offset_); + + // Skip the debug_info_offset and debug_info_size fields. + pinfo += 2 * this->offset_size_; + + if (pinfo >= this->buffer_end_) + return false; + + this->pinfo_ = pinfo; + return true; +} + +// Read the next name from the set. + +const char* +Dwarf_pubnames_table::next_name(uint8_t* flag_byte) +{ + const unsigned char* pinfo = this->pinfo_; + + // Check for end of list. The table should be terminated by an + // entry containing nothing but a DIE offset of 0. + if (pinfo + this->offset_size_ >= this->end_of_table_) + return NULL; + + // Skip the offset within the CU. If this is zero, but we're not + // at the end of the table, then we have a real pubnames entry + // whose DIE offset is 0 (likely to be a GCC bug). Since we + // don't actually use the DIE offset in building .gdb_index, + // it's harmless. + pinfo += this->offset_size_; + + if (this->is_gnu_style_) + *flag_byte = *pinfo++; + else + *flag_byte = 0; + + // Return a pointer to the string at the current location, + // and advance the pointer to the next entry. + const char* ret = reinterpret_cast(pinfo); + while (pinfo < this->buffer_end_ && *pinfo != '\0') + ++pinfo; + if (pinfo < this->buffer_end_) + ++pinfo; + + this->pinfo_ = pinfo; + return ret; +} + +// class Dwarf_die + +Dwarf_die::Dwarf_die( + Dwarf_info_reader* dwinfo, + off_t die_offset, + Dwarf_die* parent) + : dwinfo_(dwinfo), parent_(parent), die_offset_(die_offset), + child_offset_(0), sibling_offset_(0), abbrev_code_(NULL), attributes_(), + attributes_read_(false), name_(NULL), name_off_(-1), linkage_name_(NULL), + linkage_name_off_(-1), string_shndx_(0), specification_(0), + abstract_origin_(0) +{ + size_t len; + const unsigned char* pdie = dwinfo->buffer_at_offset(die_offset); + if (pdie == NULL) + return; + unsigned int code = read_unsigned_LEB_128(pdie, &len); + if (code == 0) + { + if (parent != NULL) + parent->set_sibling_offset(die_offset + len); + return; + } + this->attr_offset_ = len; + + // Lookup the abbrev code in the abbrev table. + this->abbrev_code_ = dwinfo->get_abbrev(code); +} + +// Read all the attributes of the DIE. + +bool +Dwarf_die::read_attributes() +{ + if (this->attributes_read_) + return true; + + gold_assert(this->abbrev_code_ != NULL); + + const unsigned char* pdie = + this->dwinfo_->buffer_at_offset(this->die_offset_); + if (pdie == NULL) + return false; + const unsigned char* pattr = pdie + this->attr_offset_; + + unsigned int nattr = this->abbrev_code_->attributes.size(); + this->attributes_.reserve(nattr); + for (unsigned int i = 0; i < nattr; ++i) + { + size_t len; + unsigned int attr = this->abbrev_code_->attributes[i].attr; + unsigned int form = this->abbrev_code_->attributes[i].form; + if (form == elfcpp::DW_FORM_indirect) + { + form = read_unsigned_LEB_128(pattr, &len); + pattr += len; + } + off_t attr_off = this->die_offset_ + (pattr - pdie); + bool ref_form = false; + Attribute_value attr_value; + attr_value.attr = attr; + attr_value.form = form; + attr_value.aux.shndx = 0; + switch(form) + { + case elfcpp::DW_FORM_flag_present: + attr_value.val.intval = 1; + break; + case elfcpp::DW_FORM_implicit_const: + attr_value.val.intval = + this->abbrev_code_->attributes[i].implicit_const; + break; + case elfcpp::DW_FORM_strp: + case elfcpp::DW_FORM_strp_sup: + case elfcpp::DW_FORM_line_strp: + { + off_t str_off; + if (this->dwinfo_->offset_size() == 4) + str_off = this->dwinfo_->read_from_pointer<32>(&pattr); + else + str_off = this->dwinfo_->read_from_pointer<64>(&pattr); + unsigned int shndx = + this->dwinfo_->lookup_reloc(attr_off, &str_off); + attr_value.aux.shndx = shndx; + attr_value.val.refval = str_off; + break; + } + case elfcpp::DW_FORM_strx: + case elfcpp::DW_FORM_GNU_str_index: + attr_value.val.uintval = read_unsigned_LEB_128(pattr, &len); + pattr += len; + break; + case elfcpp::DW_FORM_strx1: + attr_value.val.uintval = *pattr++; + break; + case elfcpp::DW_FORM_strx2: + attr_value.val.uintval = + this->dwinfo_->read_from_pointer<16>(&pattr); + break; + case elfcpp::DW_FORM_strx3: + attr_value.val.uintval = + this->dwinfo_->read_3bytes_from_pointer(&pattr); + break; + case elfcpp::DW_FORM_strx4: + attr_value.val.uintval = + this->dwinfo_->read_from_pointer<32>(&pattr); + break; + case elfcpp::DW_FORM_sec_offset: + { + off_t sec_off; + if (this->dwinfo_->offset_size() == 4) + sec_off = this->dwinfo_->read_from_pointer<32>(&pattr); + else + sec_off = this->dwinfo_->read_from_pointer<64>(&pattr); + unsigned int shndx = + this->dwinfo_->lookup_reloc(attr_off, &sec_off); + attr_value.aux.shndx = shndx; + attr_value.val.refval = sec_off; + ref_form = true; + break; + } + case elfcpp::DW_FORM_addr: + { + off_t sec_off; + if (this->dwinfo_->address_size() == 4) + sec_off = this->dwinfo_->read_from_pointer<32>(&pattr); + else + sec_off = this->dwinfo_->read_from_pointer<64>(&pattr); + unsigned int shndx = + this->dwinfo_->lookup_reloc(attr_off, &sec_off); + attr_value.aux.shndx = shndx; + attr_value.val.refval = sec_off; + break; + } + case elfcpp::DW_FORM_ref_addr: + { + off_t sec_off; + if (this->dwinfo_->ref_addr_size() == 4) + sec_off = this->dwinfo_->read_from_pointer<32>(&pattr); + else + sec_off = this->dwinfo_->read_from_pointer<64>(&pattr); + unsigned int shndx = + this->dwinfo_->lookup_reloc(attr_off, &sec_off); + attr_value.aux.shndx = shndx; + attr_value.val.refval = sec_off; + ref_form = true; + break; + } + case elfcpp::DW_FORM_block1: + attr_value.aux.blocklen = *pattr++; + attr_value.val.blockval = pattr; + pattr += attr_value.aux.blocklen; + break; + case elfcpp::DW_FORM_block2: + attr_value.aux.blocklen = + this->dwinfo_->read_from_pointer<16>(&pattr); + attr_value.val.blockval = pattr; + pattr += attr_value.aux.blocklen; + break; + case elfcpp::DW_FORM_block4: + attr_value.aux.blocklen = + this->dwinfo_->read_from_pointer<32>(&pattr); + attr_value.val.blockval = pattr; + pattr += attr_value.aux.blocklen; + break; + case elfcpp::DW_FORM_block: + case elfcpp::DW_FORM_exprloc: + attr_value.aux.blocklen = read_unsigned_LEB_128(pattr, &len); + attr_value.val.blockval = pattr + len; + pattr += len + attr_value.aux.blocklen; + break; + case elfcpp::DW_FORM_data1: + case elfcpp::DW_FORM_flag: + attr_value.val.intval = *pattr++; + break; + case elfcpp::DW_FORM_ref1: + attr_value.val.refval = *pattr++; + ref_form = true; + break; + case elfcpp::DW_FORM_data2: + attr_value.val.intval = + this->dwinfo_->read_from_pointer<16>(&pattr); + break; + case elfcpp::DW_FORM_ref2: + attr_value.val.refval = + this->dwinfo_->read_from_pointer<16>(&pattr); + ref_form = true; + break; + case elfcpp::DW_FORM_data4: + { + off_t sec_off; + sec_off = this->dwinfo_->read_from_pointer<32>(&pattr); + unsigned int shndx = + this->dwinfo_->lookup_reloc(attr_off, &sec_off); + attr_value.aux.shndx = shndx; + attr_value.val.intval = sec_off; + break; + } + case elfcpp::DW_FORM_ref4: + case elfcpp::DW_FORM_ref_sup4: + { + off_t sec_off; + sec_off = this->dwinfo_->read_from_pointer<32>(&pattr); + unsigned int shndx = + this->dwinfo_->lookup_reloc(attr_off, &sec_off); + attr_value.aux.shndx = shndx; + attr_value.val.refval = sec_off; + ref_form = true; + break; + } + case elfcpp::DW_FORM_data8: + { + off_t sec_off; + sec_off = this->dwinfo_->read_from_pointer<64>(&pattr); + unsigned int shndx = + this->dwinfo_->lookup_reloc(attr_off, &sec_off); + attr_value.aux.shndx = shndx; + attr_value.val.intval = sec_off; + break; + } + case elfcpp::DW_FORM_data16: + { + // For now, treat this as a 16-byte block. + attr_value.val.blockval = pattr; + attr_value.aux.blocklen = 16; + pattr += 16; + break; + } + case elfcpp::DW_FORM_ref_sig8: + attr_value.val.uintval = + this->dwinfo_->read_from_pointer<64>(&pattr); + break; + case elfcpp::DW_FORM_ref8: + case elfcpp::DW_FORM_ref_sup8: + { + off_t sec_off; + sec_off = this->dwinfo_->read_from_pointer<64>(&pattr); + unsigned int shndx = + this->dwinfo_->lookup_reloc(attr_off, &sec_off); + attr_value.aux.shndx = shndx; + attr_value.val.refval = sec_off; + ref_form = true; + break; + } + case elfcpp::DW_FORM_ref_udata: + attr_value.val.refval = read_unsigned_LEB_128(pattr, &len); + ref_form = true; + pattr += len; + break; + case elfcpp::DW_FORM_udata: + attr_value.val.uintval = read_unsigned_LEB_128(pattr, &len); + pattr += len; + break; + case elfcpp::DW_FORM_addrx: + case elfcpp::DW_FORM_GNU_addr_index: + attr_value.val.uintval = read_unsigned_LEB_128(pattr, &len); + pattr += len; + break; + case elfcpp::DW_FORM_addrx1: + attr_value.val.uintval = *pattr++; + break; + case elfcpp::DW_FORM_addrx2: + attr_value.val.uintval = + this->dwinfo_->read_from_pointer<16>(&pattr); + break; + case elfcpp::DW_FORM_addrx3: + attr_value.val.uintval = + this->dwinfo_->read_3bytes_from_pointer(&pattr); + break; + case elfcpp::DW_FORM_addrx4: + attr_value.val.uintval = + this->dwinfo_->read_from_pointer<32>(&pattr); + break; + case elfcpp::DW_FORM_sdata: + attr_value.val.intval = read_signed_LEB_128(pattr, &len); + pattr += len; + break; + case elfcpp::DW_FORM_string: + attr_value.val.stringval = reinterpret_cast(pattr); + len = strlen(attr_value.val.stringval); + pattr += len + 1; + break; + case elfcpp::DW_FORM_loclistx: + case elfcpp::DW_FORM_rnglistx: + attr_value.val.uintval = read_unsigned_LEB_128(pattr, &len); + pattr += len; + break; + default: + return false; + } + + // Cache the most frequently-requested attributes. + switch (attr) + { + case elfcpp::DW_AT_name: + if (form == elfcpp::DW_FORM_string) + this->name_ = attr_value.val.stringval; + else if (form == elfcpp::DW_FORM_strp) + { + // All indirect strings should refer to the same + // string section, so we just save the last one seen. + this->string_shndx_ = attr_value.aux.shndx; + this->name_off_ = attr_value.val.refval; + } + break; + case elfcpp::DW_AT_linkage_name: + case elfcpp::DW_AT_MIPS_linkage_name: + if (form == elfcpp::DW_FORM_string) + this->linkage_name_ = attr_value.val.stringval; + else if (form == elfcpp::DW_FORM_strp) + { + // All indirect strings should refer to the same + // string section, so we just save the last one seen. + this->string_shndx_ = attr_value.aux.shndx; + this->linkage_name_off_ = attr_value.val.refval; + } + break; + case elfcpp::DW_AT_specification: + if (ref_form) + this->specification_ = attr_value.val.refval; + break; + case elfcpp::DW_AT_abstract_origin: + if (ref_form) + this->abstract_origin_ = attr_value.val.refval; + break; + case elfcpp::DW_AT_sibling: + if (ref_form && attr_value.aux.shndx == 0) + this->sibling_offset_ = attr_value.val.refval; + default: + break; + } + + this->attributes_.push_back(attr_value); + } + + // Now that we know where the next DIE begins, record the offset + // to avoid later recalculation. + if (this->has_children()) + this->child_offset_ = this->die_offset_ + (pattr - pdie); + else + this->sibling_offset_ = this->die_offset_ + (pattr - pdie); + + this->attributes_read_ = true; + return true; +} + +// Skip all the attributes of the DIE and return the offset of the next DIE. + +off_t +Dwarf_die::skip_attributes() +{ + gold_assert(this->abbrev_code_ != NULL); + + const unsigned char* pdie = + this->dwinfo_->buffer_at_offset(this->die_offset_); + if (pdie == NULL) + return 0; + const unsigned char* pattr = pdie + this->attr_offset_; + + for (unsigned int i = 0; i < this->abbrev_code_->attributes.size(); ++i) + { + size_t len; + unsigned int form = this->abbrev_code_->attributes[i].form; + if (form == elfcpp::DW_FORM_indirect) + { + form = read_unsigned_LEB_128(pattr, &len); + pattr += len; + } + switch(form) + { + case elfcpp::DW_FORM_flag_present: + case elfcpp::DW_FORM_implicit_const: + break; + case elfcpp::DW_FORM_strp: + case elfcpp::DW_FORM_sec_offset: + case elfcpp::DW_FORM_strp_sup: + case elfcpp::DW_FORM_line_strp: + pattr += this->dwinfo_->offset_size(); + break; + case elfcpp::DW_FORM_addr: + pattr += this->dwinfo_->address_size(); + break; + case elfcpp::DW_FORM_ref_addr: + pattr += this->dwinfo_->ref_addr_size(); + break; + case elfcpp::DW_FORM_block1: + pattr += 1 + *pattr; + break; + case elfcpp::DW_FORM_block2: + { + uint16_t block_size; + block_size = this->dwinfo_->read_from_pointer<16>(&pattr); + pattr += block_size; + break; + } + case elfcpp::DW_FORM_block4: + { + uint32_t block_size; + block_size = this->dwinfo_->read_from_pointer<32>(&pattr); + pattr += block_size; + break; + } + case elfcpp::DW_FORM_block: + case elfcpp::DW_FORM_exprloc: + { + uint64_t block_size; + block_size = read_unsigned_LEB_128(pattr, &len); + pattr += len + block_size; + break; + } + case elfcpp::DW_FORM_data1: + case elfcpp::DW_FORM_ref1: + case elfcpp::DW_FORM_flag: + case elfcpp::DW_FORM_strx1: + case elfcpp::DW_FORM_addrx1: + pattr += 1; + break; + case elfcpp::DW_FORM_data2: + case elfcpp::DW_FORM_ref2: + case elfcpp::DW_FORM_strx2: + case elfcpp::DW_FORM_addrx2: + pattr += 2; + break; + case elfcpp::DW_FORM_strx3: + case elfcpp::DW_FORM_addrx3: + pattr += 3; + break; + case elfcpp::DW_FORM_data4: + case elfcpp::DW_FORM_ref4: + case elfcpp::DW_FORM_ref_sup4: + case elfcpp::DW_FORM_strx4: + case elfcpp::DW_FORM_addrx4: + pattr += 4; + break; + case elfcpp::DW_FORM_data8: + case elfcpp::DW_FORM_ref8: + case elfcpp::DW_FORM_ref_sig8: + case elfcpp::DW_FORM_ref_sup8: + pattr += 8; + break; + case elfcpp::DW_FORM_data16: + pattr += 16; + break; + case elfcpp::DW_FORM_ref_udata: + case elfcpp::DW_FORM_udata: + case elfcpp::DW_FORM_addrx: + case elfcpp::DW_FORM_strx: + case elfcpp::DW_FORM_loclistx: + case elfcpp::DW_FORM_rnglistx: + case elfcpp::DW_FORM_GNU_addr_index: + case elfcpp::DW_FORM_GNU_str_index: + read_unsigned_LEB_128(pattr, &len); + pattr += len; + break; + case elfcpp::DW_FORM_sdata: + read_signed_LEB_128(pattr, &len); + pattr += len; + break; + case elfcpp::DW_FORM_string: + len = strlen(reinterpret_cast(pattr)); + pattr += len + 1; + break; + default: + return 0; + } + } + + return this->die_offset_ + (pattr - pdie); +} + +// Get the name of the DIE and cache it. + +void +Dwarf_die::set_name() +{ + if (this->name_ != NULL || !this->read_attributes()) + return; + if (this->name_off_ != -1) + this->name_ = this->dwinfo_->get_string(this->name_off_, + this->string_shndx_); +} + +// Get the linkage name of the DIE and cache it. + +void +Dwarf_die::set_linkage_name() +{ + if (this->linkage_name_ != NULL || !this->read_attributes()) + return; + if (this->linkage_name_off_ != -1) + this->linkage_name_ = this->dwinfo_->get_string(this->linkage_name_off_, + this->string_shndx_); +} + +// Return the value of attribute ATTR. + +const Dwarf_die::Attribute_value* +Dwarf_die::attribute(unsigned int attr) +{ + if (!this->read_attributes()) + return NULL; + for (unsigned int i = 0; i < this->attributes_.size(); ++i) + { + if (this->attributes_[i].attr == attr) + return &this->attributes_[i]; + } + return NULL; +} + +const char* +Dwarf_die::string_attribute(unsigned int attr) +{ + const Attribute_value* attr_val = this->attribute(attr); + if (attr_val == NULL) + return NULL; + switch (attr_val->form) + { + case elfcpp::DW_FORM_string: + return attr_val->val.stringval; + case elfcpp::DW_FORM_strp: + return this->dwinfo_->get_string(attr_val->val.refval, + attr_val->aux.shndx); + default: + return NULL; + } +} int64_t -read_signed_LEB_128(const unsigned char* buffer, size_t* len) +Dwarf_die::int_attribute(unsigned int attr) { - int64_t result = 0; - int shift = 0; - size_t num_read = 0; - unsigned char byte; + const Attribute_value* attr_val = this->attribute(attr); + if (attr_val == NULL) + return 0; + switch (attr_val->form) + { + case elfcpp::DW_FORM_flag_present: + case elfcpp::DW_FORM_data1: + case elfcpp::DW_FORM_flag: + case elfcpp::DW_FORM_data2: + case elfcpp::DW_FORM_data4: + case elfcpp::DW_FORM_data8: + case elfcpp::DW_FORM_sdata: + return attr_val->val.intval; + default: + return 0; + } +} - do +uint64_t +Dwarf_die::uint_attribute(unsigned int attr) +{ + const Attribute_value* attr_val = this->attribute(attr); + if (attr_val == NULL) + return 0; + switch (attr_val->form) { - byte = *buffer++; - num_read++; - result |= (static_cast(byte & 0x7f) << shift); - shift += 7; + case elfcpp::DW_FORM_flag_present: + case elfcpp::DW_FORM_data1: + case elfcpp::DW_FORM_flag: + case elfcpp::DW_FORM_data4: + case elfcpp::DW_FORM_data8: + case elfcpp::DW_FORM_ref_sig8: + case elfcpp::DW_FORM_udata: + return attr_val->val.uintval; + default: + return 0; } - while (byte & 0x80); +} - if ((shift < 8 * static_cast(sizeof(result))) && (byte & 0x40)) - result |= -((static_cast(1)) << shift); - *len = num_read; - return result; +off_t +Dwarf_die::ref_attribute(unsigned int attr, unsigned int* shndx) +{ + const Attribute_value* attr_val = this->attribute(attr); + if (attr_val == NULL) + return -1; + switch (attr_val->form) + { + case elfcpp::DW_FORM_sec_offset: + case elfcpp::DW_FORM_addr: + case elfcpp::DW_FORM_ref_addr: + case elfcpp::DW_FORM_ref1: + case elfcpp::DW_FORM_ref2: + case elfcpp::DW_FORM_ref4: + case elfcpp::DW_FORM_ref8: + case elfcpp::DW_FORM_ref_udata: + *shndx = attr_val->aux.shndx; + return attr_val->val.refval; + case elfcpp::DW_FORM_ref_sig8: + *shndx = attr_val->aux.shndx; + return attr_val->val.uintval; + case elfcpp::DW_FORM_data4: + case elfcpp::DW_FORM_data8: + *shndx = attr_val->aux.shndx; + return attr_val->val.intval; + default: + return -1; + } +} + +off_t +Dwarf_die::address_attribute(unsigned int attr, unsigned int* shndx) +{ + const Attribute_value* attr_val = this->attribute(attr); + if (attr_val == NULL || attr_val->form != elfcpp::DW_FORM_addr) + return -1; + + *shndx = attr_val->aux.shndx; + return attr_val->val.refval; } -} // End anonymous namespace. +// Return the offset of this DIE's first child. + +off_t +Dwarf_die::child_offset() +{ + gold_assert(this->abbrev_code_ != NULL); + if (!this->has_children()) + return 0; + if (this->child_offset_ == 0) + this->child_offset_ = this->skip_attributes(); + return this->child_offset_; +} +// Return the offset of this DIE's next sibling. -namespace gold { +off_t +Dwarf_die::sibling_offset() +{ + gold_assert(this->abbrev_code_ != NULL); -// This is the format of a DWARF2/3 line state machine that we process -// opcodes using. There is no need for anything outside the lineinfo -// processor to know how this works. + if (this->sibling_offset_ != 0) + return this->sibling_offset_; + + if (!this->has_children()) + { + this->sibling_offset_ = this->skip_attributes(); + return this->sibling_offset_; + } + + if (this->has_sibling_attribute()) + { + if (!this->read_attributes()) + return 0; + if (this->sibling_offset_ != 0) + return this->sibling_offset_; + } + + // Skip over the children. + off_t child_offset = this->child_offset(); + while (child_offset > 0) + { + Dwarf_die die(this->dwinfo_, child_offset, this); + // The Dwarf_die ctor will set this DIE's sibling offset + // when it reads a zero abbrev code. + if (die.tag() == 0) + break; + child_offset = die.sibling_offset(); + } + + // This should be set by now. If not, there was a problem reading + // the DWARF info, and we return 0. + return this->sibling_offset_; +} + +// class Dwarf_info_reader + +// Begin parsing the debug info. This calls visit_compilation_unit() +// or visit_type_unit() for each compilation or type unit found in the +// section, and visit_die() for each top-level DIE. + +void +Dwarf_info_reader::parse() +{ + if (this->object_->is_big_endian()) + { +#if defined(HAVE_TARGET_32_BIG) || defined(HAVE_TARGET_64_BIG) + this->do_parse(); +#else + gold_unreachable(); +#endif + } + else + { +#if defined(HAVE_TARGET_32_LITTLE) || defined(HAVE_TARGET_64_LITTLE) + this->do_parse(); +#else + gold_unreachable(); +#endif + } +} + +template +void +Dwarf_info_reader::do_parse() +{ + // Get the section contents and decompress if necessary. + section_size_type buffer_size; + bool buffer_is_new; + this->buffer_ = this->object_->decompressed_section_contents(this->shndx_, + &buffer_size, + &buffer_is_new); + if (this->buffer_ == NULL || buffer_size == 0) + return; + this->buffer_end_ = this->buffer_ + buffer_size; + + // The offset of this input section in the output section. + off_t section_offset = this->object_->output_section_offset(this->shndx_); + + // Start tracking relocations for this section. + this->reloc_mapper_ = make_elf_reloc_mapper(this->object_, this->symtab_, + this->symtab_size_); + this->reloc_mapper_->initialize(this->reloc_shndx_, this->reloc_type_); + + // Loop over compilation units (or type units). + unsigned int abbrev_shndx = this->abbrev_shndx_; + off_t abbrev_offset = 0; + const unsigned char* pinfo = this->buffer_; + while (pinfo < this->buffer_end_) + { + // Read the compilation (or type) unit header. + const unsigned char* cu_start = pinfo; + this->cu_offset_ = cu_start - this->buffer_; + this->cu_length_ = this->buffer_end_ - cu_start; + + // Read unit_length (4 or 12 bytes). + if (!this->check_buffer(pinfo + 4)) + break; + uint32_t unit_length = + elfcpp::Swap_unaligned<32, big_endian>::readval(pinfo); + pinfo += 4; + if (unit_length == 0xffffffff) + { + if (!this->check_buffer(pinfo + 8)) + break; + unit_length = elfcpp::Swap_unaligned<64, big_endian>::readval(pinfo); + pinfo += 8; + this->offset_size_ = 8; + } + else + this->offset_size_ = 4; + if (!this->check_buffer(pinfo + unit_length)) + break; + const unsigned char* cu_end = pinfo + unit_length; + this->cu_length_ = cu_end - cu_start; + if (!this->check_buffer(pinfo + 2 + this->offset_size_ + 1)) + break; + + // Read version (2 bytes). + this->cu_version_ = + elfcpp::Swap_unaligned<16, big_endian>::readval(pinfo); + pinfo += 2; + + // DWARF 5: Read the unit type (1 byte) and address size (1 byte). + if (this->cu_version_ >= 5) + { + this->unit_type_ = *pinfo++; + this->address_size_ = *pinfo++; + } + + // Read debug_abbrev_offset (4 or 8 bytes). + if (this->offset_size_ == 4) + abbrev_offset = elfcpp::Swap_unaligned<32, big_endian>::readval(pinfo); + else + abbrev_offset = elfcpp::Swap_unaligned<64, big_endian>::readval(pinfo); + if (this->reloc_shndx_ > 0) + { + off_t reloc_offset = pinfo - this->buffer_; + off_t value; + abbrev_shndx = + this->reloc_mapper_->get_reloc_target(reloc_offset, &value); + if (abbrev_shndx == 0) + return; + if (this->reloc_type_ == elfcpp::SHT_REL) + abbrev_offset += value; + else + abbrev_offset = value; + } + pinfo += this->offset_size_; + + // DWARF 2-4: Read address_size (1 byte). + if (this->cu_version_ < 5) + this->address_size_ = *pinfo++; + + // For type units, read the two extra fields. + uint64_t signature = 0; + off_t type_offset = 0; + if (this->is_type_unit()) + { + if (!this->check_buffer(pinfo + 8 + this->offset_size_)) + break; + + // Read type_signature (8 bytes). + signature = elfcpp::Swap_unaligned<64, big_endian>::readval(pinfo); + pinfo += 8; + + // Read type_offset (4 or 8 bytes). + if (this->offset_size_ == 4) + type_offset = + elfcpp::Swap_unaligned<32, big_endian>::readval(pinfo); + else + type_offset = + elfcpp::Swap_unaligned<64, big_endian>::readval(pinfo); + pinfo += this->offset_size_; + } + + // Read the .debug_abbrev table. + this->abbrev_table_.read_abbrevs(this->object_, abbrev_shndx, + abbrev_offset); + + // Visit the root DIE. + Dwarf_die root_die(this, + pinfo - (this->buffer_ + this->cu_offset_), + NULL); + if (root_die.tag() != 0) + { + // Visit the CU or TU. + if (this->is_type_unit()) + this->visit_type_unit(section_offset + this->cu_offset_, + cu_end - cu_start, type_offset, signature, + &root_die); + else + this->visit_compilation_unit(section_offset + this->cu_offset_, + cu_end - cu_start, &root_die); + } + + // Advance to the next CU. + pinfo = cu_end; + } + + if (buffer_is_new) + { + delete[] this->buffer_; + this->buffer_ = NULL; + } +} + +// Read the DWARF string table. + +bool +Dwarf_info_reader::do_read_string_table(unsigned int string_shndx) +{ + Relobj* object = this->object_; + + // If we don't have relocations, string_shndx will be 0, and + // we'll have to hunt for the .debug_str section. + if (string_shndx == 0) + { + for (unsigned int i = 1; i < this->object_->shnum(); ++i) + { + std::string name = object->section_name(i); + if (name == ".debug_str" || name == ".zdebug_str") + { + string_shndx = i; + this->string_output_section_offset_ = + object->output_section_offset(i); + break; + } + } + if (string_shndx == 0) + return false; + } + + if (this->owns_string_buffer_ && this->string_buffer_ != NULL) + { + delete[] this->string_buffer_; + this->owns_string_buffer_ = false; + } + + // Get the secton contents and decompress if necessary. + section_size_type buffer_size; + const unsigned char* buffer = + object->decompressed_section_contents(string_shndx, + &buffer_size, + &this->owns_string_buffer_); + this->string_buffer_ = reinterpret_cast(buffer); + this->string_buffer_end_ = this->string_buffer_ + buffer_size; + this->string_shndx_ = string_shndx; + return true; +} + +// Read a possibly unaligned integer of SIZE. +template +inline typename elfcpp::Valtype_base::Valtype +Dwarf_info_reader::read_from_pointer(const unsigned char* source) +{ + typename elfcpp::Valtype_base::Valtype return_value; + if (this->object_->is_big_endian()) + return_value = elfcpp::Swap_unaligned::readval(source); + else + return_value = elfcpp::Swap_unaligned::readval(source); + return return_value; +} + +// Read a possibly unaligned integer of SIZE. Update SOURCE after read. +template +inline typename elfcpp::Valtype_base::Valtype +Dwarf_info_reader::read_from_pointer(const unsigned char** source) +{ + typename elfcpp::Valtype_base::Valtype return_value; + if (this->object_->is_big_endian()) + return_value = elfcpp::Swap_unaligned::readval(*source); + else + return_value = elfcpp::Swap_unaligned::readval(*source); + *source += valsize / 8; + return return_value; +} + +// Read a 3-byte integer. Update SOURCE after read. +inline typename elfcpp::Valtype_base<32>::Valtype +Dwarf_info_reader::read_3bytes_from_pointer(const unsigned char** source) +{ + typename elfcpp::Valtype_base<32>::Valtype return_value; + if (this->object_->is_big_endian()) + return_value = ((*source)[0] << 16) | ((*source)[1] << 8) | (*source)[2]; + else + return_value = ((*source)[2] << 16) | ((*source)[1] << 8) | (*source)[0]; + *source += 3; + return return_value; +} + +// Look for a relocation at offset ATTR_OFF in the dwarf info, +// and return the section index and offset of the target. + +unsigned int +Dwarf_info_reader::lookup_reloc(off_t attr_off, off_t* target_off) +{ + off_t value; + attr_off += this->cu_offset_; + unsigned int shndx = this->reloc_mapper_->get_reloc_target(attr_off, &value); + if (shndx == 0) + return 0; + if (this->reloc_type_ == elfcpp::SHT_REL) + *target_off += value; + else + *target_off = value; + return shndx; +} + +// Return a string from the DWARF string table. + +const char* +Dwarf_info_reader::get_string(off_t str_off, unsigned int string_shndx) +{ + if (!this->read_string_table(string_shndx)) + return NULL; + + // Correct the offset. For incremental update links, we have a + // relocated offset that is relative to the output section, but + // here we need an offset relative to the input section. + str_off -= this->string_output_section_offset_; + + const char* p = this->string_buffer_ + str_off; + + if (p < this->string_buffer_ || p >= this->string_buffer_end_) + return NULL; + + return p; +} + +// The following are default, do-nothing, implementations of the +// hook methods normally provided by a derived class. We provide +// default implementations rather than no implementation so that +// a derived class needs to implement only the hooks that it needs +// to use. + +// Process a compilation unit and parse its child DIE. + +void +Dwarf_info_reader::visit_compilation_unit(off_t, off_t, Dwarf_die*) +{ +} + +// Process a type unit and parse its child DIE. + +void +Dwarf_info_reader::visit_type_unit(off_t, off_t, off_t, uint64_t, Dwarf_die*) +{ +} + +// Print a warning about a corrupt debug section. + +void +Dwarf_info_reader::warn_corrupt_debug_section() const +{ + gold_warning(_("%s: corrupt debug info in %s"), + this->object_->name().c_str(), + this->object_->section_name(this->shndx_).c_str()); +} + +// class Sized_dwarf_line_info struct LineStateMachine { @@ -114,60 +1793,177 @@ ResetLineStateMachine(struct LineStateMachine* lsm, bool default_is_stmt) lsm->end_sequence = false; } +template +Sized_dwarf_line_info::Sized_dwarf_line_info( + Object* object, + unsigned int read_shndx) + : data_valid_(false), buffer_(NULL), buffer_start_(NULL), + str_buffer_(NULL), str_buffer_start_(NULL), + reloc_mapper_(NULL), symtab_buffer_(NULL), directories_(), files_(), + current_header_index_(-1), reloc_map_(), line_number_map_() +{ + unsigned int debug_line_shndx = 0; + unsigned int debug_line_str_shndx = 0; + + for (unsigned int i = 1; i < object->shnum(); ++i) + { + section_size_type buffer_size; + bool is_new = false; + + // FIXME: do this more efficiently: section_name() isn't super-fast + std::string name = object->section_name(i); + if (name == ".debug_line" || name == ".zdebug_line") + { + this->buffer_ = + object->decompressed_section_contents(i, &buffer_size, &is_new); + if (is_new) + this->buffer_start_ = this->buffer_; + this->buffer_end_ = this->buffer_ + buffer_size; + debug_line_shndx = i; + } + else if (name == ".debug_line_str" || name == ".zdebug_line_str") + { + this->str_buffer_ = + object->decompressed_section_contents(i, &buffer_size, &is_new); + if (is_new) + this->str_buffer_start_ = this->str_buffer_; + this->str_buffer_end_ = this->str_buffer_ + buffer_size; + debug_line_str_shndx = i; + } + if (debug_line_shndx > 0 && debug_line_str_shndx > 0) + break; + } + if (this->buffer_ == NULL) + return; + + // Find the relocation section for ".debug_line". + // We expect these for relobjs (.o's) but not dynobjs (.so's). + unsigned int reloc_shndx = 0; + for (unsigned int i = 0; i < object->shnum(); ++i) + { + unsigned int reloc_sh_type = object->section_type(i); + if ((reloc_sh_type == elfcpp::SHT_REL + || reloc_sh_type == elfcpp::SHT_RELA) + && object->section_info(i) == debug_line_shndx) + { + reloc_shndx = i; + this->track_relocs_type_ = reloc_sh_type; + break; + } + } + + // Finally, we need the symtab section to interpret the relocs. + if (reloc_shndx != 0) + { + unsigned int symtab_shndx; + for (symtab_shndx = 0; symtab_shndx < object->shnum(); ++symtab_shndx) + if (object->section_type(symtab_shndx) == elfcpp::SHT_SYMTAB) + { + this->symtab_buffer_ = object->section_contents( + symtab_shndx, &this->symtab_buffer_size_, false); + break; + } + if (this->symtab_buffer_ == NULL) + return; + } + + this->reloc_mapper_ = + new Sized_elf_reloc_mapper(object, + this->symtab_buffer_, + this->symtab_buffer_size_); + if (!this->reloc_mapper_->initialize(reloc_shndx, this->track_relocs_type_)) + return; + + // Now that we have successfully read all the data, parse the debug + // info. + this->data_valid_ = true; + this->read_line_mappings(read_shndx); +} + // Read the DWARF header. template const unsigned char* -Dwarf_line_info::read_header_prolog( +Sized_dwarf_line_info::read_header_prolog( const unsigned char* lineptr) { - uint32_t initial_length = elfcpp::Swap<32, big_endian>::readval(lineptr); + uint32_t initial_length = elfcpp::Swap_unaligned<32, big_endian>::readval(lineptr); lineptr += 4; - // In DWARF2/3, if the initial length is all 1 bits, then the offset + // In DWARF, if the initial length is all 1 bits, then the offset // size is 8 and we need to read the next 8 bytes for the real length. if (initial_length == 0xffffffff) { - header_.offset_size = 8; - initial_length = elfcpp::Swap<64, big_endian>::readval(lineptr); + this->header_.offset_size = 8; + initial_length = elfcpp::Swap_unaligned<64, big_endian>::readval(lineptr); lineptr += 8; } else - header_.offset_size = 4; + this->header_.offset_size = 4; - header_.total_length = initial_length; + this->header_.total_length = initial_length; - gold_assert(lineptr + header_.total_length <= buffer_end_); + this->end_of_unit_ = lineptr + initial_length; + gold_assert(this->end_of_unit_ <= buffer_end_); - header_.version = elfcpp::Swap<16, big_endian>::readval(lineptr); + this->header_.version = + elfcpp::Swap_unaligned<16, big_endian>::readval(lineptr); lineptr += 2; - if (header_.offset_size == 4) - header_.prologue_length = elfcpp::Swap<32, big_endian>::readval(lineptr); + // We can only read versions 2-5 of the DWARF line number table. + // For other versions, just skip the entire line number table. + if (this->header_.version < 2 || this->header_.version > 5) + return this->end_of_unit_; + + // DWARF 5 only: address size and segment selector. + if (this->header_.version >= 5) + { + this->header_.address_size = *lineptr; + // We ignore the segment selector. + lineptr += 2; + } + + if (this->header_.offset_size == 4) + this->header_.prologue_length = + elfcpp::Swap_unaligned<32, big_endian>::readval(lineptr); else - header_.prologue_length = elfcpp::Swap<64, big_endian>::readval(lineptr); - lineptr += header_.offset_size; + this->header_.prologue_length = + elfcpp::Swap_unaligned<64, big_endian>::readval(lineptr); + lineptr += this->header_.offset_size; + + this->end_of_header_length_ = lineptr; - header_.min_insn_length = *lineptr; + this->header_.min_insn_length = *lineptr; lineptr += 1; - header_.default_is_stmt = *lineptr; + if (this->header_.version < 4) + this->header_.max_ops_per_insn = 1; + else + { + // DWARF 4 added the maximum_operations_per_instruction field. + this->header_.max_ops_per_insn = *lineptr; + lineptr += 1; + // TODO: Add support for values other than 1. + gold_assert(this->header_.max_ops_per_insn == 1); + } + + this->header_.default_is_stmt = *lineptr; lineptr += 1; - header_.line_base = *reinterpret_cast(lineptr); + this->header_.line_base = *reinterpret_cast(lineptr); lineptr += 1; - header_.line_range = *lineptr; + this->header_.line_range = *lineptr; lineptr += 1; - header_.opcode_base = *lineptr; + this->header_.opcode_base = *lineptr; lineptr += 1; - header_.std_opcode_lengths.reserve(header_.opcode_base + 1); - header_.std_opcode_lengths[0] = 0; - for (int i = 1; i < header_.opcode_base; i++) + this->header_.std_opcode_lengths.resize(this->header_.opcode_base + 1); + this->header_.std_opcode_lengths[0] = 0; + for (int i = 1; i < this->header_.opcode_base; i++) { - header_.std_opcode_lengths[i] = *lineptr; + this->header_.std_opcode_lengths[i] = *lineptr; lineptr += 1; } @@ -176,22 +1972,36 @@ Dwarf_line_info::read_header_prolog( // The header for a debug_line section is mildly complicated, because // the line info is very tightly encoded. +// This routine is for DWARF versions 2, 3, and 4. template const unsigned char* -Dwarf_line_info::read_header_tables( +Sized_dwarf_line_info::read_header_tables_v2( const unsigned char* lineptr) { + ++this->current_header_index_; + + // Create a new directories_ entry and a new files_ entry for our new + // header. We initialize each with a single empty element, because + // dwarf indexes directory and filenames starting at 1. + gold_assert(static_cast(this->directories_.size()) + == this->current_header_index_); + gold_assert(static_cast(this->files_.size()) + == this->current_header_index_); + this->directories_.push_back(std::vector(1)); + this->files_.push_back(std::vector >(1)); + // It is legal for the directory entry table to be empty. if (*lineptr) { int dirindex = 1; while (*lineptr) { - const unsigned char* dirname = lineptr; - gold_assert(dirindex == static_cast(directories_.size())); - directories_.push_back(reinterpret_cast(dirname)); - lineptr += directories_.back().size() + 1; + const char* dirname = reinterpret_cast(lineptr); + gold_assert(dirindex + == static_cast(this->directories_.back().size())); + this->directories_.back().push_back(dirname); + lineptr += this->directories_.back().back().size() + 1; dirindex++; } } @@ -208,18 +2018,21 @@ Dwarf_line_info::read_header_tables( lineptr += strlen(filename) + 1; uint64_t dirindex = read_unsigned_LEB_128(lineptr, &len); - if (dirindex >= directories_.size()) - dirindex = 0; lineptr += len; + if (dirindex >= this->directories_.back().size()) + dirindex = 0; + int dirindexi = static_cast(dirindex); + read_unsigned_LEB_128(lineptr, &len); // mod_time lineptr += len; read_unsigned_LEB_128(lineptr, &len); // filelength lineptr += len; - gold_assert(fileindex == static_cast(files_.size())); - files_.push_back(std::pair(dirindex, filename)); + gold_assert(fileindex + == static_cast(this->files_.back().size())); + this->files_.back().push_back(std::make_pair(dirindexi, filename)); fileindex++; } } @@ -228,15 +2041,174 @@ Dwarf_line_info::read_header_tables( return lineptr; } -// Process a single opcode in the .debug.line structure. +// This routine is for DWARF version 5. + +template +const unsigned char* +Sized_dwarf_line_info::read_header_tables_v5( + const unsigned char* lineptr) +{ + size_t len; + + ++this->current_header_index_; + + gold_assert(static_cast(this->directories_.size()) + == this->current_header_index_); + gold_assert(static_cast(this->files_.size()) + == this->current_header_index_); + + // Read the directory list. + unsigned int format_count = *lineptr; + lineptr += 1; + + unsigned int *types = new unsigned int[format_count]; + unsigned int *forms = new unsigned int[format_count]; + + for (unsigned int i = 0; i < format_count; i++) + { + types[i] = read_unsigned_LEB_128(lineptr, &len); + lineptr += len; + forms[i] = read_unsigned_LEB_128(lineptr, &len); + lineptr += len; + } + + uint64_t entry_count = read_unsigned_LEB_128(lineptr, &len); + lineptr += len; + this->directories_.push_back(std::vector(0)); + std::vector& dir_list = this->directories_.back(); + + for (unsigned int j = 0; j < entry_count; j++) + { + std::string dirname; + + for (unsigned int i = 0; i < format_count; i++) + { + if (types[i] == elfcpp::DW_LNCT_path) + { + if (forms[i] == elfcpp::DW_FORM_string) + { + dirname = reinterpret_cast(lineptr); + lineptr += dirname.size() + 1; + } + else if (forms[i] == elfcpp::DW_FORM_line_strp) + { + uint64_t offset; + if (this->header_.offset_size == 4) + offset = + elfcpp::Swap_unaligned<32, big_endian>::readval(lineptr); + else + offset = + elfcpp::Swap_unaligned<64, big_endian>::readval(lineptr); + typename Reloc_map::const_iterator it + = this->reloc_map_.find(lineptr - this->buffer_); + if (it != reloc_map_.end()) + { + if (this->track_relocs_type_ == elfcpp::SHT_RELA) + offset = 0; + offset += it->second.second; + } + lineptr += this->header_.offset_size; + dirname = reinterpret_cast(this->str_buffer_ + + offset); + } + else + return lineptr; + } + else + return lineptr; + } + dir_list.push_back(dirname); + } + + delete[] types; + delete[] forms; + + // Read the filenames list. + format_count = *lineptr; + lineptr += 1; + + types = new unsigned int[format_count]; + forms = new unsigned int[format_count]; + + for (unsigned int i = 0; i < format_count; i++) + { + types[i] = read_unsigned_LEB_128(lineptr, &len); + lineptr += len; + forms[i] = read_unsigned_LEB_128(lineptr, &len); + lineptr += len; + } -// Templating on size and big_endian would yield more efficient (and -// simpler) code, but would bloat the binary. Speed isn't important -// here. + entry_count = read_unsigned_LEB_128(lineptr, &len); + lineptr += len; + this->files_.push_back( + std::vector >(0)); + std::vector >& file_list = this->files_.back(); + + for (unsigned int j = 0; j < entry_count; j++) + { + const char* path = NULL; + int dirindex = 0; + + for (unsigned int i = 0; i < format_count; i++) + { + if (types[i] == elfcpp::DW_LNCT_path) + { + if (forms[i] == elfcpp::DW_FORM_string) + { + path = reinterpret_cast(lineptr); + lineptr += strlen(path) + 1; + } + else if (forms[i] == elfcpp::DW_FORM_line_strp) + { + uint64_t offset; + if (this->header_.offset_size == 4) + offset = elfcpp::Swap_unaligned<32, big_endian>::readval(lineptr); + else + offset = elfcpp::Swap_unaligned<64, big_endian>::readval(lineptr); + typename Reloc_map::const_iterator it + = this->reloc_map_.find(lineptr - this->buffer_); + if (it != reloc_map_.end()) + { + if (this->track_relocs_type_ == elfcpp::SHT_RELA) + offset = 0; + offset += it->second.second; + } + lineptr += this->header_.offset_size; + path = reinterpret_cast(this->str_buffer_ + + offset); + } + else + return lineptr; + } + else if (types[i] == elfcpp::DW_LNCT_directory_index) + { + if (forms[i] == elfcpp::DW_FORM_udata) + { + dirindex = read_unsigned_LEB_128(lineptr, &len); + lineptr += len; + } + else + return lineptr; + } + else + return lineptr; + } + gold_debug(DEBUG_LOCATION, "File %3d: %s", + static_cast(file_list.size()), path); + file_list.push_back(std::make_pair(dirindex, path)); + } + + delete[] types; + delete[] forms; + + return lineptr; +} + +// Process a single opcode in the .debug.line structure. template bool -Dwarf_line_info::process_one_opcode( +Sized_dwarf_line_info::process_one_opcode( const unsigned char* start, struct LineStateMachine* lsm, size_t* len) { size_t oplen = 0; @@ -247,15 +2219,15 @@ Dwarf_line_info::process_one_opcode( // If the opcode is great than the opcode_base, it is a special // opcode. Most line programs consist mainly of special opcodes. - if (opcode >= header_.opcode_base) + if (opcode >= this->header_.opcode_base) { - opcode -= header_.opcode_base; - const int advance_address = ((opcode / header_.line_range) - * header_.min_insn_length); + opcode -= this->header_.opcode_base; + const int advance_address = ((opcode / this->header_.line_range) + * this->header_.min_insn_length); lsm->address += advance_address; - const int advance_line = ((opcode % header_.line_range) - + header_.line_base); + const int advance_line = ((opcode % this->header_.line_range) + + this->header_.line_base); lsm->line_num += advance_line; lsm->basic_block = true; *len = oplen; @@ -275,13 +2247,13 @@ Dwarf_line_info::process_one_opcode( const uint64_t advance_address = read_unsigned_LEB_128(start, &templen); oplen += templen; - lsm->address += header_.min_insn_length * advance_address; + lsm->address += this->header_.min_insn_length * advance_address; } break; case elfcpp::DW_LNS_advance_line: { - const uint64_t advance_line = read_signed_LEB_128(start, &templen); + const int64_t advance_line = read_signed_LEB_128(start, &templen); oplen += templen; lsm->line_num += advance_line; } @@ -314,7 +2286,7 @@ Dwarf_line_info::process_one_opcode( case elfcpp::DW_LNS_fixed_advance_pc: { int advance_address; - advance_address = elfcpp::Swap<16, big_endian>::readval(start); + advance_address = elfcpp::Swap_unaligned<16, big_endian>::readval(start); oplen += 2; lsm->address += advance_address; } @@ -322,9 +2294,9 @@ Dwarf_line_info::process_one_opcode( case elfcpp::DW_LNS_const_add_pc: { - const int advance_address = (header_.min_insn_length - * ((255 - header_.opcode_base) - / header_.line_range)); + const int advance_address = (this->header_.min_insn_length + * ((255 - this->header_.opcode_base) + / this->header_.line_range)); lsm->address += advance_address; } break; @@ -342,17 +2314,42 @@ Dwarf_line_info::process_one_opcode( switch (extended_op) { case elfcpp::DW_LNE_end_sequence: + // This means that the current byte is the one immediately + // after a set of instructions. Record the current line + // for up to one less than the current address. + lsm->line_num = -1; lsm->end_sequence = true; *len = oplen; return true; case elfcpp::DW_LNE_set_address: - // FIXME: modify the address based on the reloc - lsm->address = elfcpp::Swap::readval(start); - // FIXME: set lsm->shndx from the reloc - lsm->shndx = 1; - break; - + { + lsm->address = + elfcpp::Swap_unaligned::readval(start); + typename Reloc_map::const_iterator it + = this->reloc_map_.find(start - this->buffer_); + if (it != reloc_map_.end()) + { + // If this is a SHT_RELA section, then ignore the + // section contents. This assumes that this is a + // straight reloc which just uses the reloc addend. + // The reloc addend has already been included in the + // symbol value. + if (this->track_relocs_type_ == elfcpp::SHT_RELA) + lsm->address = 0; + // Add in the symbol value. + lsm->address += it->second.second; + lsm->shndx = it->second.first; + } + else + { + // If we're a normal .o file, with relocs, every + // set_address should have an associated relocation. + if (this->input_is_relobj()) + this->data_valid_ = false; + } + break; + } case elfcpp::DW_LNE_define_file: { const char* filename = reinterpret_cast(start); @@ -360,17 +2357,18 @@ Dwarf_line_info::process_one_opcode( start += templen; uint64_t dirindex = read_unsigned_LEB_128(start, &templen); - if (dirindex >= directories_.size()) - dirindex = 0; - oplen += templen; - read_unsigned_LEB_128(start, &templen); // mod_time - oplen += templen; + if (dirindex >= this->directories_.back().size()) + dirindex = 0; + int dirindexi = static_cast(dirindex); - read_unsigned_LEB_128(start, &templen); // filelength - oplen += templen; + // This opcode takes two additional ULEB128 parameters + // (mod_time and filelength), but we don't use those + // values. Because OPLEN already tells us how far to + // skip to the next opcode, we don't need to read + // them at all. - files_.push_back(std::pair(dirindex, + this->files_.back().push_back(std::make_pair(dirindexi, filename)); } break; @@ -381,7 +2379,7 @@ Dwarf_line_info::process_one_opcode( default: { // Ignore unknown opcode silently - for (int i = 0; i < header_.std_opcode_lengths[opcode]; i++) + for (int i = 0; i < this->header_.std_opcode_lengths[opcode]; i++) { size_t templen; read_unsigned_LEB_128(start, &templen); @@ -400,52 +2398,100 @@ Dwarf_line_info::process_one_opcode( template unsigned const char* -Dwarf_line_info::read_lines(unsigned const char* lineptr) +Sized_dwarf_line_info::read_lines(unsigned const char* lineptr, + unsigned const char* endptr, + unsigned int shndx) { struct LineStateMachine lsm; - // LENGTHSTART is the place the length field is based on. It is the - // point in the header after the initial length field. - const unsigned char* lengthstart = buffer_; - - // In 64 bit dwarf, the initial length is 12 bytes, because of the - // 0xffffffff at the start. - if (header_.offset_size == 8) - lengthstart += 12; - else - lengthstart += 4; - - while (lineptr < lengthstart + header_.total_length) + while (lineptr < endptr) { - ResetLineStateMachine(&lsm, header_.default_is_stmt); + ResetLineStateMachine(&lsm, this->header_.default_is_stmt); while (!lsm.end_sequence) { size_t oplength; + + if (lineptr >= endptr) + break; + bool add_line = this->process_one_opcode(lineptr, &lsm, &oplength); - if (add_line) + lineptr += oplength; + + if (add_line + && (shndx == -1U || lsm.shndx == -1U || shndx == lsm.shndx)) { Offset_to_lineno_entry entry - = { lsm.address, lsm.file_num, lsm.line_num }; - line_number_map_[lsm.shndx].push_back(entry); + = { static_cast(lsm.address), + this->current_header_index_, + static_cast(lsm.file_num), + true, lsm.line_num }; + std::vector& + map(this->line_number_map_[lsm.shndx]); + // If we see two consecutive entries with the same + // offset and a real line number, then mark the first + // one as non-canonical. + if (!map.empty() + && (map.back().offset == static_cast(lsm.address)) + && lsm.line_num != -1 + && map.back().line_num != -1) + map.back().last_line_for_offset = false; + map.push_back(entry); } - lineptr += oplength; } } - return lengthstart + header_.total_length; + return endptr; +} + +// Read the relocations into a Reloc_map. + +template +void +Sized_dwarf_line_info::read_relocs() +{ + if (this->symtab_buffer_ == NULL) + return; + + off_t value; + off_t reloc_offset; + while ((reloc_offset = this->reloc_mapper_->next_offset()) != -1) + { + const unsigned int shndx = + this->reloc_mapper_->get_reloc_target(reloc_offset, &value); + + // There is no reason to record non-ordinary section indexes, or + // SHN_UNDEF, because they will never match the real section. + if (shndx != 0) + this->reloc_map_[reloc_offset] = std::make_pair(shndx, value); + + this->reloc_mapper_->advance(reloc_offset + 1); + } } +// Read the line number info. + template void -Dwarf_line_info::read_line_mappings() +Sized_dwarf_line_info::read_line_mappings(unsigned int shndx) { - while (buffer_ < buffer_end_) + gold_assert(this->data_valid_ == true); + + this->read_relocs(); + while (this->buffer_ < this->buffer_end_) { - const unsigned char* lineptr = buffer_; + const unsigned char* lineptr = this->buffer_; lineptr = this->read_header_prolog(lineptr); - lineptr = this->read_header_tables(lineptr); - lineptr = this->read_lines(lineptr); - buffer_ = lineptr; + if (this->header_.version >= 2 && this->header_.version <= 4) + { + lineptr = this->read_header_tables_v2(lineptr); + lineptr = this->read_lines(lineptr, this->end_of_unit_, shndx); + } + else if (this->header_.version == 5) + { + lineptr = this->read_header_tables_v5(lineptr); + lineptr = this->read_lines(lineptr, this->end_of_unit_, shndx); + } + this->buffer_ = this->end_of_unit_; } // Sort the lines numbers, so addr2line can use binary search. @@ -453,37 +2499,229 @@ Dwarf_line_info::read_line_mappings() it != line_number_map_.end(); ++it) // Each vector needs to be sorted by offset. - sort(it->second.begin(), it->second.end()); + std::sort(it->second.begin(), it->second.end()); } -// Return a string for a file name and line number. +// Some processing depends on whether the input is a .o file or not. +// For instance, .o files have relocs, and have .debug_lines +// information on a per section basis. .so files, on the other hand, +// lack relocs, and offsets are unique, so we can ignore the section +// information. + +template +bool +Sized_dwarf_line_info::input_is_relobj() +{ + // Only .o files have relocs and the symtab buffer that goes with them. + return this->symtab_buffer_ != NULL; +} + +// Given an Offset_to_lineno_entry vector, and an offset, figure out +// if the offset points into a function according to the vector (see +// comments below for the algorithm). If it does, return an iterator +// into the vector that points to the line-number that contains that +// offset. If not, it returns vector::end(). + +static std::vector::const_iterator +offset_to_iterator(const std::vector* offsets, + off_t offset) +{ + const Offset_to_lineno_entry lookup_key = { offset, 0, 0, true, 0 }; + + // lower_bound() returns the smallest offset which is >= lookup_key. + // If no offset in offsets is >= lookup_key, returns end(). + std::vector::const_iterator it + = std::lower_bound(offsets->begin(), offsets->end(), lookup_key); + + // This code is easiest to understand with a concrete example. + // Here's a possible offsets array: + // {{offset = 3211, header_num = 0, file_num = 1, last, line_num = 16}, // 0 + // {offset = 3224, header_num = 0, file_num = 1, last, line_num = 20}, // 1 + // {offset = 3226, header_num = 0, file_num = 1, last, line_num = 22}, // 2 + // {offset = 3231, header_num = 0, file_num = 1, last, line_num = 25}, // 3 + // {offset = 3232, header_num = 0, file_num = 1, last, line_num = -1}, // 4 + // {offset = 3232, header_num = 0, file_num = 1, last, line_num = 65}, // 5 + // {offset = 3235, header_num = 0, file_num = 1, last, line_num = 66}, // 6 + // {offset = 3236, header_num = 0, file_num = 1, last, line_num = -1}, // 7 + // {offset = 5764, header_num = 0, file_num = 1, last, line_num = 48}, // 8 + // {offset = 5764, header_num = 0, file_num = 1,!last, line_num = 47}, // 9 + // {offset = 5765, header_num = 0, file_num = 1, last, line_num = 49}, // 10 + // {offset = 5767, header_num = 0, file_num = 1, last, line_num = 50}, // 11 + // {offset = 5768, header_num = 0, file_num = 1, last, line_num = 51}, // 12 + // {offset = 5773, header_num = 0, file_num = 1, last, line_num = -1}, // 13 + // {offset = 5787, header_num = 1, file_num = 1, last, line_num = 19}, // 14 + // {offset = 5790, header_num = 1, file_num = 1, last, line_num = 20}, // 15 + // {offset = 5793, header_num = 1, file_num = 1, last, line_num = 67}, // 16 + // {offset = 5793, header_num = 1, file_num = 1, last, line_num = -1}, // 17 + // {offset = 5793, header_num = 1, file_num = 1,!last, line_num = 66}, // 18 + // {offset = 5795, header_num = 1, file_num = 1, last, line_num = 68}, // 19 + // {offset = 5798, header_num = 1, file_num = 1, last, line_num = -1}, // 20 + // The entries with line_num == -1 mark the end of a function: the + // associated offset is one past the last instruction in the + // function. This can correspond to the beginning of the next + // function (as is true for offset 3232); alternately, there can be + // a gap between the end of one function and the start of the next + // (as is true for some others, most obviously from 3236->5764). + // + // Case 1: lookup_key has offset == 10. lower_bound returns + // offsets[0]. Since it's not an exact match and we're + // at the beginning of offsets, we return end() (invalid). + // Case 2: lookup_key has offset 10000. lower_bound returns + // offset[21] (end()). We return end() (invalid). + // Case 3: lookup_key has offset == 3211. lower_bound matches + // offsets[0] exactly, and that's the entry we return. + // Case 4: lookup_key has offset == 3232. lower_bound returns + // offsets[4]. That's an exact match, but indicates + // end-of-function. We check if offsets[5] is also an + // exact match but not end-of-function. It is, so we + // return offsets[5]. + // Case 5: lookup_key has offset == 3214. lower_bound returns + // offsets[1]. Since it's not an exact match, we back + // up to the offset that's < lookup_key, offsets[0]. + // We note offsets[0] is a valid entry (not end-of-function), + // so that's the entry we return. + // Case 6: lookup_key has offset == 4000. lower_bound returns + // offsets[8]. Since it's not an exact match, we back + // up to offsets[7]. Since offsets[7] indicates + // end-of-function, we know lookup_key is between + // functions, so we return end() (not a valid offset). + // Case 7: lookup_key has offset == 5794. lower_bound returns + // offsets[19]. Since it's not an exact match, we back + // up to offsets[16]. Note we back up to the *first* + // entry with offset 5793, not just offsets[19-1]. + // We note offsets[16] is a valid entry, so we return it. + // If offsets[16] had had line_num == -1, we would have + // checked offsets[17]. The reason for this is that + // 16 and 17 can be in an arbitrary order, since we sort + // only by offset and last_line_for_offset. (Note it + // doesn't help to use line_number as a tertiary sort key, + // since sometimes we want the -1 to be first and sometimes + // we want it to be last.) + + // This deals with cases (1) and (2). + if ((it == offsets->begin() && offset < it->offset) + || it == offsets->end()) + return offsets->end(); + + // This deals with cases (3) and (4). + if (offset == it->offset) + { + while (it != offsets->end() + && it->offset == offset + && it->line_num == -1) + ++it; + if (it == offsets->end() || it->offset != offset) + return offsets->end(); + else + return it; + } + + // This handles the first part of case (7) -- we back up to the + // *first* entry that has the offset that's behind us. + gold_assert(it != offsets->begin()); + std::vector::const_iterator range_end = it; + --it; + const off_t range_value = it->offset; + while (it != offsets->begin() && (it-1)->offset == range_value) + --it; + + // This handles cases (5), (6), and (7): if any entry in the + // equal_range [it, range_end) has a line_num != -1, it's a valid + // match. If not, we're not in a function. The line number we saw + // last for an offset will be sorted first, so it'll get returned if + // it's present. + for (; it != range_end; ++it) + if (it->line_num != -1) + return it; + return offsets->end(); +} + +// Returns the canonical filename:lineno for the address passed in. +// If other_lines is not NULL, appends the non-canonical lines +// assigned to the same address. template std::string -Dwarf_line_info::addr2line(unsigned int shndx, off_t offset) +Sized_dwarf_line_info::do_addr2line( + unsigned int shndx, + off_t offset, + std::vector* other_lines) { - const Offset_to_lineno_entry lookup_key = { offset, 0, 0 }; - std::vector& offsets = line_number_map_[shndx]; - typename std::vector::const_iterator it - = std::lower_bound(offsets.begin(), offsets.end(), lookup_key); + gold_debug(DEBUG_LOCATION, "do_addr2line: shndx %u offset %08x", + shndx, static_cast(offset)); + + if (this->data_valid_ == false) + return ""; + + const std::vector* offsets; + // If we do not have reloc information, then our input is a .so or + // some similar data structure where all the information is held in + // the offset. In that case, we ignore the input shndx. + if (this->input_is_relobj()) + offsets = &this->line_number_map_[shndx]; + else + offsets = &this->line_number_map_[-1U]; + if (offsets->empty()) + return ""; - // If we found an exact match, great, otherwise find the last entry - // before the passed-in offset. - if (it->offset > offset) + typename std::vector::const_iterator it + = offset_to_iterator(offsets, offset); + if (it == offsets->end()) + return ""; + + std::string result = this->format_file_lineno(*it); + gold_debug(DEBUG_LOCATION, "do_addr2line: canonical result: %s", + result.c_str()); + if (other_lines != NULL) { - if (it == offsets.begin()) - return ""; - --it; - gold_assert(it->offset < offset); + unsigned int last_file_num = it->file_num; + int last_line_num = it->line_num; + // Return up to 4 more locations from the beginning of the function + // for fuzzy matching. + for (++it; it != offsets->end(); ++it) + { + if (it->offset == offset && it->line_num == -1) + continue; // The end of a previous function. + if (it->line_num == -1) + break; // The end of the current function. + if (it->file_num != last_file_num || it->line_num != last_line_num) + { + other_lines->push_back(this->format_file_lineno(*it)); + gold_debug(DEBUG_LOCATION, "do_addr2line: other: %s", + other_lines->back().c_str()); + last_file_num = it->file_num; + last_line_num = it->line_num; + } + if (it->offset > offset && other_lines->size() >= 4) + break; + } } - // Convert the file_num + line_num into a string. + return result; +} + +// Convert the file_num + line_num into a string. + +template +std::string +Sized_dwarf_line_info::format_file_lineno( + const Offset_to_lineno_entry& loc) const +{ std::string ret; - gold_assert(it->file_num < static_cast(files_.size())); - const std::pair& filename_pair = files_[it->file_num]; - gold_assert(filename_pair.first < static_cast(directories_.size())); - const std::string& dirname = directories_[filename_pair.first]; + + gold_assert(loc.header_num < static_cast(this->files_.size())); + gold_assert(loc.file_num + < static_cast(this->files_[loc.header_num].size())); + const std::pair& filename_pair + = this->files_[loc.header_num][loc.file_num]; const std::string& filename = filename_pair.second; + + gold_assert(loc.header_num < static_cast(this->directories_.size())); + gold_assert(filename_pair.first + < static_cast(this->directories_[loc.header_num].size())); + const std::string& dirname + = this->directories_[loc.header_num][filename_pair.first]; + if (!dirname.empty()) { ret += dirname; @@ -494,31 +2732,150 @@ Dwarf_line_info::addr2line(unsigned int shndx, off_t offset) ret = "(unknown)"; char buffer[64]; // enough to hold a line number - snprintf(buffer, sizeof(buffer), "%d", it->line_num); + snprintf(buffer, sizeof(buffer), "%d", loc.line_num); ret += ":"; ret += buffer; return ret; } +// Dwarf_line_info routines. + +static unsigned int next_generation_count = 0; + +struct Addr2line_cache_entry +{ + Object* object; + unsigned int shndx; + Dwarf_line_info* dwarf_line_info; + unsigned int generation_count; + unsigned int access_count; + + Addr2line_cache_entry(Object* o, unsigned int s, Dwarf_line_info* d) + : object(o), shndx(s), dwarf_line_info(d), + generation_count(next_generation_count), access_count(0) + { + if (next_generation_count < (1U << 31)) + ++next_generation_count; + } +}; +// We expect this cache to be small, so don't bother with a hashtable +// or priority queue or anything: just use a simple vector. +static std::vector addr2line_cache; + +std::string +Dwarf_line_info::one_addr2line(Object* object, + unsigned int shndx, off_t offset, + size_t cache_size, + std::vector* other_lines) +{ + Dwarf_line_info* lineinfo = NULL; + std::vector::iterator it; + + // First, check the cache. If we hit, update the counts. + for (it = addr2line_cache.begin(); it != addr2line_cache.end(); ++it) + { + if (it->object == object && it->shndx == shndx) + { + lineinfo = it->dwarf_line_info; + it->generation_count = next_generation_count; + // We cap generation_count at 2^31 -1 to avoid overflow. + if (next_generation_count < (1U << 31)) + ++next_generation_count; + // We cap access_count at 31 so 2^access_count doesn't overflow + if (it->access_count < 31) + ++it->access_count; + break; + } + } + + // If we don't hit the cache, create a new object and insert into the + // cache. + if (lineinfo == NULL) + { + switch (parameters->size_and_endianness()) + { +#ifdef HAVE_TARGET_32_LITTLE + case Parameters::TARGET_32_LITTLE: + lineinfo = new Sized_dwarf_line_info<32, false>(object, shndx); break; +#endif +#ifdef HAVE_TARGET_32_BIG + case Parameters::TARGET_32_BIG: + lineinfo = new Sized_dwarf_line_info<32, true>(object, shndx); break; +#endif +#ifdef HAVE_TARGET_64_LITTLE + case Parameters::TARGET_64_LITTLE: + lineinfo = new Sized_dwarf_line_info<64, false>(object, shndx); break; +#endif +#ifdef HAVE_TARGET_64_BIG + case Parameters::TARGET_64_BIG: + lineinfo = new Sized_dwarf_line_info<64, true>(object, shndx); break; +#endif + default: + gold_unreachable(); + } + addr2line_cache.push_back(Addr2line_cache_entry(object, shndx, lineinfo)); + } + + // Now that we have our object, figure out the answer + std::string retval = lineinfo->addr2line(shndx, offset, other_lines); + + // Finally, if our cache has grown too big, delete old objects. We + // assume the common (probably only) case is deleting only one object. + // We use a pretty simple scheme to evict: function of LRU and MFU. + while (addr2line_cache.size() > cache_size) + { + unsigned int lowest_score = ~0U; + std::vector::iterator lowest + = addr2line_cache.end(); + for (it = addr2line_cache.begin(); it != addr2line_cache.end(); ++it) + { + const unsigned int score = (it->generation_count + + (1U << it->access_count)); + if (score < lowest_score) + { + lowest_score = score; + lowest = it; + } + } + if (lowest != addr2line_cache.end()) + { + delete lowest->dwarf_line_info; + addr2line_cache.erase(lowest); + } + } + + return retval; +} + +void +Dwarf_line_info::clear_addr2line_cache() +{ + for (std::vector::iterator it = addr2line_cache.begin(); + it != addr2line_cache.end(); + ++it) + delete it->dwarf_line_info; + addr2line_cache.clear(); +} + #ifdef HAVE_TARGET_32_LITTLE template -class Dwarf_line_info<32, false>; +class Sized_dwarf_line_info<32, false>; #endif #ifdef HAVE_TARGET_32_BIG template -class Dwarf_line_info<32, true>; +class Sized_dwarf_line_info<32, true>; #endif #ifdef HAVE_TARGET_64_LITTLE template -class Dwarf_line_info<64, false>; +class Sized_dwarf_line_info<64, false>; #endif #ifdef HAVE_TARGET_64_BIG template -class Dwarf_line_info<64, true>; +class Sized_dwarf_line_info<64, true>; #endif } // End namespace gold.