--- /dev/null
+// reduced_debug_output.cc -- output reduced debugging information to save space
+
+// Copyright 2008 Free Software Foundation, Inc.
+// Written by Caleb Howe <cshowe@google.com>.
+
+// This file is part of gold.
+
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
+// MA 02110-1301, USA.
+
+#include "gold.h"
+
+#include "parameters.h"
+#include "options.h"
+#include "dwarf.h"
+#include "dwarf_reader.h"
+#include "reduced_debug_output.h"
+
+#include <vector>
+
+namespace gold
+{
+
+void
+write_unsigned_LEB_128(std::vector<unsigned char>* buffer, uint64_t value)
+{
+ do
+ {
+ unsigned char current_byte = value & 0x7f;
+ value >>= 7;
+ if (value != 0)
+ {
+ current_byte |= 0x80;
+ }
+ buffer->push_back(current_byte);
+ }
+ while (value != 0);
+}
+
+size_t
+get_length_as_unsigned_LEB_128(uint64_t value)
+{
+ size_t length = 0;
+ do
+ {
+ unsigned char current_byte = value & 0x7f;
+ value >>= 7;
+ if (value != 0)
+ {
+ current_byte |= 0x80;
+ }
+ length++;
+ }
+ while (value != 0);
+ return length;
+}
+
+template <int valsize>
+void Insert_into_vector(std::vector<unsigned char>* destination,
+ typename elfcpp::Valtype_base<valsize>::Valtype value)
+{
+ union
+ {
+ unsigned char buffer[valsize / 8];
+ long long align;
+ } u;
+ if (parameters->target().is_big_endian())
+ elfcpp::Swap<valsize, true>::writeval(u.buffer, value);
+ else
+ elfcpp::Swap<valsize, false>::writeval(u.buffer, value);
+ destination->insert(destination->end(), u.buffer, u.buffer + valsize / 8);
+}
+
+template <int valsize>
+typename elfcpp::Valtype_base<valsize>::Valtype
+read_from_pointer(unsigned char** source)
+{
+ typename elfcpp::Valtype_base<valsize>::Valtype return_value;
+ if (parameters->target().is_big_endian())
+ return_value = elfcpp::Swap_unaligned<valsize, true>::readval(*source);
+ else
+ return_value = elfcpp::Swap_unaligned<valsize, false>::readval(*source);
+ *source += valsize / 8;
+ return return_value;
+}
+
+// Given a pointer to the beginning of a die and the beginning of the associated
+// abbreviation fills in die_end with the end of the information entry. If
+// successful returns true. Get_die_end also takes a pointer to the end of the
+// buffer containing the die. If die_end would be beyond the end of the
+// buffer, or if an unsupported dwarf form is encountered returns false.
+bool
+Output_reduced_debug_info_section::get_die_end(
+ unsigned char* die, unsigned char* abbrev, unsigned char** die_end,
+ unsigned char* buffer_end, int address_size, bool is64)
+{
+ size_t LEB_size;
+ uint64_t LEB_decoded;
+ for(;;)
+ {
+ uint64_t attribute = read_unsigned_LEB_128(abbrev, &LEB_size);
+ abbrev += LEB_size;
+ elfcpp::DW_FORM form =
+ static_cast<elfcpp::DW_FORM>(read_unsigned_LEB_128(abbrev,
+ &LEB_size));
+ abbrev += LEB_size;
+ if (!(attribute || form))
+ break;
+ if (die >= buffer_end)
+ return false;
+ switch(form)
+ {
+ case elfcpp::DW_FORM_null:
+ break;
+ case elfcpp::DW_FORM_strp:
+ die += is64 ? 8 : 4;
+ break;
+ case elfcpp::DW_FORM_addr:
+ case elfcpp::DW_FORM_ref_addr:
+ die += address_size;
+ break;
+ case elfcpp::DW_FORM_block1:
+ die += *die;
+ die += 1;
+ break;
+ case elfcpp::DW_FORM_block2:
+ {
+ uint16_t block_size;
+ block_size = read_from_pointer<16>(&die);
+ die += block_size;
+ break;
+ }
+ case elfcpp::DW_FORM_block4:
+ {
+ uint32_t block_size;
+ block_size = read_from_pointer<32>(&die);
+ die += block_size;
+ break;
+ }
+ case elfcpp::DW_FORM_block:
+ LEB_decoded = read_unsigned_LEB_128(die, &LEB_size);
+ die += (LEB_decoded + LEB_size);
+ break;
+ case elfcpp::DW_FORM_data1:
+ case elfcpp::DW_FORM_ref1:
+ case elfcpp::DW_FORM_flag:
+ die += 1;
+ break;
+ case elfcpp::DW_FORM_data2:
+ case elfcpp::DW_FORM_ref2:
+ die += 2;
+ break;
+ case elfcpp::DW_FORM_data4:
+ case elfcpp::DW_FORM_ref4:
+ die += 4;
+ break;
+ case elfcpp::DW_FORM_data8:
+ case elfcpp::DW_FORM_ref8:
+ die += 8;
+ break;
+ case elfcpp::DW_FORM_ref_udata:
+ case elfcpp::DW_FORM_udata:
+ read_unsigned_LEB_128(die, &LEB_size);
+ die += LEB_size;
+ break;
+ case elfcpp::DW_FORM_string:
+ {
+ size_t length = strlen(reinterpret_cast<char*>(die));
+ die += length + 1;
+ break;
+ }
+ case elfcpp::DW_FORM_sdata:
+ case elfcpp::DW_FORM_indirect:
+ return false;
+ }
+ }
+ *die_end = die;
+ return true;
+}
+
+void
+Output_reduced_debug_abbrev_section::set_final_data_size()
+{
+ if (this->sized_ || this->failed_)
+ return;
+
+ uint64_t abbrev_number;
+ size_t LEB_size;
+ unsigned char* abbrev_data = this->postprocessing_buffer();
+ unsigned char* abbrev_end = this->postprocessing_buffer() +
+ this->postprocessing_buffer_size();
+ this->write_to_postprocessing_buffer();
+ while(abbrev_data < abbrev_end)
+ {
+ uint64_t abbrev_offset = abbrev_data - this->postprocessing_buffer();
+ while((abbrev_number = read_unsigned_LEB_128(abbrev_data, &LEB_size)))
+ {
+ if (abbrev_data >= abbrev_end)
+ {
+ failed("Debug abbreviations extend beyond .debug_abbrev "
+ "section; failed to reduce debug abbreviations");
+ return;
+ }
+ abbrev_data += LEB_size;
+
+ // Together with the abbreviation number these fields make up
+ // the header for each abbreviation
+ uint64_t abbrev_type = read_unsigned_LEB_128(abbrev_data, &LEB_size);
+ abbrev_data += LEB_size;
+
+ // This would ordinarily be the has_children field of the
+ // abbreviation. But it's going to be false after reducting the
+ // information, so there's no point in storing it
+ abbrev_data++;
+
+ // Read to the end of the current abbreviation
+ // This is indicated by two zero unsigned LEBs in a row. We don't
+ // need to parse the data yet, so we just scan through the data
+ // looking for two consecutive 0 bytes indicating the end of the
+ // abbreviation
+ unsigned char* current_abbrev;
+ for (current_abbrev = abbrev_data;
+ current_abbrev[0] || current_abbrev[1];
+ current_abbrev++)
+ {
+ if (current_abbrev >= abbrev_end)
+ {
+ this->failed(_("Debug abbreviations extend beyond "
+ ".debug_abbrev section; failed to reduce "
+ "debug abbreviations"));
+ return;
+ }
+ }
+ // Account for the two nulls and advance to the start of the
+ // next abbreviation.
+ current_abbrev += 2;
+
+ // We're eliminating every entry except for compile units, so we
+ // only need to store abbreviations that describe them
+ if (abbrev_type == elfcpp::DW_TAG_compile_unit)
+ {
+ write_unsigned_LEB_128(&this->data_, ++this->abbrev_count_);
+ write_unsigned_LEB_128(&this->data_, abbrev_type);
+ // has_children is false for all entries
+ this->data_.push_back(0);
+ this->abbrev_mapping_[std::make_pair(abbrev_offset,
+ abbrev_number)] =
+ std::make_pair(abbrev_count_, this->data_.size());
+ this->data_.insert(this->data_.end(), abbrev_data,
+ current_abbrev);
+ }
+ abbrev_data = current_abbrev;
+ }
+ gold_assert(LEB_size == 1);
+ abbrev_data += LEB_size;
+ }
+ // Null terminate the list of abbreviations
+ this->data_.push_back(0);
+ this->set_data_size(data_.size());
+ this->sized_ = true;
+}
+
+void
+Output_reduced_debug_abbrev_section::do_write(Output_file* of)
+{
+ off_t offset = this->offset();
+ off_t data_size = this->data_size();
+ unsigned char* view = of->get_output_view(offset, data_size);
+ if (this->failed_)
+ memcpy(view, this->postprocessing_buffer(),
+ this->postprocessing_buffer_size());
+ else
+ memcpy(view, &this->data_.front(), data_size);
+ of->write_output_view(offset, data_size, view);
+}
+
+// Locates the abbreviation with abbreviation_number abbrev_number in the
+// abbreviation table at offset abbrev_offset. abbrev_number is updated with
+// its new abbreviation number and a pointer to the beginning of the
+// abbreviation is returned.
+unsigned char*
+Output_reduced_debug_abbrev_section::get_new_abbrev(
+ uint64_t* abbrev_number, uint64_t abbrev_offset)
+{
+ set_final_data_size();
+ std::pair<uint64_t, uint64_t> abbrev_info =
+ this->abbrev_mapping_[std::make_pair(abbrev_offset, *abbrev_number)];
+ *abbrev_number = abbrev_info.first;
+ return &this->data_[abbrev_info.second];
+}
+
+void Output_reduced_debug_info_section::set_final_data_size()
+{
+ if (this->failed_)
+ return;
+ unsigned char* debug_info = this->postprocessing_buffer();
+ unsigned char* debug_info_end = (this->postprocessing_buffer()
+ + this->postprocessing_buffer_size());
+ unsigned char* next_compile_unit;
+ this->write_to_postprocessing_buffer();
+
+ while (debug_info < debug_info_end)
+ {
+ uint32_t compile_unit_start = read_from_pointer<32>(&debug_info);
+ // The first 4 bytes of each compile unit determine whether or
+ // not we're using dwarf32 or dwarf64. This is not necessarily
+ // related to whether the binary is 32 or 64 bits.
+ if (compile_unit_start == 0xFFFFFFFF)
+ {
+ // Technically the size can be up to 96 bits. Rather than handle
+ // 96/128 bit integers we just truncate the size at 64 bits.
+ if (0 != read_from_pointer<32>(&debug_info))
+ {
+ this->failed(_("Extremely large compile unit in debug info; "
+ "failed to reduce debug info"));
+ return;
+ }
+ const int dwarf64_header_size = sizeof(uint64_t) + sizeof(uint16_t) +
+ sizeof(uint64_t) + sizeof(uint8_t);
+ if (debug_info + dwarf64_header_size >= debug_info_end)
+ {
+ this->failed(_("Debug info extends beyond .debug_info section;"
+ "failed to reduce debug info"));
+ return;
+ }
+
+ uint64_t compile_unit_size = read_from_pointer<64>(&debug_info);
+ next_compile_unit = debug_info + compile_unit_size;
+ uint16_t version = read_from_pointer<16>(&debug_info);
+ uint64_t abbrev_offset = read_from_pointer<64>(&debug_info);
+ uint8_t address_size = read_from_pointer<8>(&debug_info);
+ size_t LEB_size;
+ uint64_t abbreviation_number = read_unsigned_LEB_128(debug_info,
+ &LEB_size);
+ debug_info += LEB_size;
+ unsigned char* die_abbrev = this->associated_abbrev_->get_new_abbrev(
+ &abbreviation_number, abbrev_offset);
+ unsigned char* die_end;
+ if (!this->get_die_end(debug_info, die_abbrev, &die_end,
+ debug_info_end, address_size, true))
+ {
+ this->failed(_("Invalid DIE in debug info; "
+ "failed to reduce debug info"));
+ return;
+ }
+
+ Insert_into_vector<32>(&this->data_, 0xFFFFFFFF);
+ Insert_into_vector<32>(&this->data_, 0);
+ Insert_into_vector<64>(
+ &this->data_,
+ (11 + get_length_as_unsigned_LEB_128(abbreviation_number)
+ + die_end - debug_info));
+ Insert_into_vector<16>(&this->data_, version);
+ Insert_into_vector<64>(&this->data_, 0);
+ Insert_into_vector<8>(&this->data_, address_size);
+ write_unsigned_LEB_128(&this->data_, abbreviation_number);
+ this->data_.insert(this->data_.end(), debug_info, die_end);
+ }
+ else
+ {
+ const int dwarf32_header_size =
+ sizeof(uint16_t) + sizeof(uint32_t) + sizeof(uint8_t);
+ if (debug_info + dwarf32_header_size >= debug_info_end)
+ {
+ this->failed(_("Debug info extends beyond .debug_info section; "
+ "failed to reduce debug info"));
+ return;
+ }
+ uint32_t compile_unit_size = compile_unit_start;
+ next_compile_unit = debug_info + compile_unit_size;
+ uint16_t version = read_from_pointer<16>(&debug_info);
+ uint32_t abbrev_offset = read_from_pointer<32>(&debug_info);
+ uint8_t address_size = read_from_pointer<8>(&debug_info);
+ size_t LEB_size;
+ uint64_t abbreviation_number = read_unsigned_LEB_128(debug_info,
+ &LEB_size);
+ debug_info += LEB_size;
+ unsigned char* die_abbrev = this->associated_abbrev_->get_new_abbrev(
+ &abbreviation_number, abbrev_offset);
+ unsigned char* die_end;
+ if (!this->get_die_end(debug_info, die_abbrev, &die_end,
+ debug_info_end, address_size, false))
+ {
+ this->failed(_("Invalid DIE in debug info; "
+ "failed to reduce debug info"));
+ return;
+ }
+
+ Insert_into_vector<32>(
+ &this->data_,
+ (7 + get_length_as_unsigned_LEB_128(abbreviation_number)
+ + die_end - debug_info));
+ Insert_into_vector<16>(&this->data_, version);
+ Insert_into_vector<32>(&this->data_, 0);
+ Insert_into_vector<8>(&this->data_, address_size);
+ write_unsigned_LEB_128(&this->data_, abbreviation_number);
+ this->data_.insert(this->data_.end(), debug_info, die_end);
+ }
+ debug_info = next_compile_unit;
+ }
+ this->set_data_size(data_.size());
+}
+
+void Output_reduced_debug_info_section::do_write(Output_file* of)
+{
+ off_t offset = this->offset();
+ off_t data_size = this->data_size();
+ unsigned char* view = of->get_output_view(offset, data_size);
+ if (this->failed_)
+ memcpy(view, this->postprocessing_buffer(),
+ this->postprocessing_buffer_size());
+ else
+ memcpy(view, &this->data_.front(), data_size);
+ of->write_output_view(offset, data_size, view);
+}
+
+} // End namespace gold.
--- /dev/null
+// reduced_debug_output.h -- reduce debugging information -*- C++ -*-
+
+// Copyright 2008 Free Software Foundation, Inc.
+// Written by Caleb Howe <cshowe@google.com>.
+
+// This file is part of gold.
+
+// This program is free software; you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation; either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
+// MA 02110-1301, USA.
+
+// Reduce the size of the debug sections by emitting only debug line number
+// information. We still need to emit skeleton debug_info and debug_abbrev
+// sections for standard tools to parse the debug information correctly. These
+// classes remove all debug information entries from the .debug_info section
+// except for those describing compilation units as these DIEs contain
+// references to the debug line information needed by most parsers.
+
+#ifndef GOLD_REDUCED_DEBUG_OUTPUT_H
+#define GOLD_REDUCED_DEBUG_OUTPUT_H
+
+#include <map>
+#include <utility>
+#include <vector>
+
+#include "output.h"
+
+namespace gold
+{
+
+class Output_reduced_debug_abbrev_section : public Output_section
+{
+ public:
+ Output_reduced_debug_abbrev_section(const char* name, elfcpp::Elf_Word flags,
+ elfcpp::Elf_Xword type)
+ : Output_section(name, flags, type), sized_(false),
+ abbrev_count_(0), failed_(false)
+ { this->set_requires_postprocessing(); }
+
+ unsigned char* get_new_abbrev(uint64_t* abbrev_number,
+ uint64_t abbrev_offset);
+
+ protected:
+ // Set the final data size.
+ void
+ set_final_data_size();
+
+ // Write out the new debug abbreviations
+ void
+ do_write(Output_file*);
+
+ private:
+ void
+ failed(std::string reason)
+ {
+ gold_warning(reason.c_str());
+ failed_ = true;
+ }
+
+ // The reduced debug abbreviations
+ std::vector<unsigned char> data_;
+
+ // We map the abbreviation table offset and abbreviation number of the
+ // old abbreviation to the number and size of the new abbreviation.
+ std::map<std::pair<uint64_t, uint64_t>,
+ std::pair<uint64_t, uint64_t> > abbrev_mapping_;
+
+ bool sized_;
+
+ // The count of abbreviations in the output data
+ int abbrev_count_;
+
+ // Whether or not the debug reduction has failed for any reason
+ bool failed_;
+};
+
+class Output_reduced_debug_info_section : public Output_section
+{
+ public:
+ Output_reduced_debug_info_section(const char* name, elfcpp::Elf_Word flags,
+ elfcpp::Elf_Xword type)
+ : Output_section(name, flags, type), failed_(false)
+ { this->set_requires_postprocessing(); }
+
+ void
+ set_abbreviations(Output_reduced_debug_abbrev_section* abbrevs)
+ { associated_abbrev_ = abbrevs; }
+
+ protected:
+ // Set the final data size.
+ void
+ set_final_data_size();
+
+ // Write out the new debug info
+ void
+ do_write(Output_file*);
+
+ private:
+ void
+ failed(std::string reason)
+ {
+ gold_warning(reason.c_str());
+ this->failed_ = true;
+ }
+
+ // Given a pointer to the beginning of a die and the beginning of the
+ // associated abbreviation fills in die_end with the end of the information
+ // entry. If successful returns true. Get_die_end also takes a pointer to
+ // the end of the buffer containing the die. If die_end would be beyond the
+ // end of the buffer, or if an unsupported dwarf form is encountered returns
+ // false.
+ bool
+ get_die_end(unsigned char* die, unsigned char* abbrev,
+ unsigned char** die_end, unsigned char* buffer_end,
+ int address_size, bool is64);
+
+ // The reduced debug info
+ std::vector<unsigned char> data_;
+
+ // Each debug info section needs to be associated with a debug abbrev section
+ Output_reduced_debug_abbrev_section* associated_abbrev_;
+
+ // Whether or not the debug reduction has failed for any reason
+ bool failed_;
+};
+
+} // End namespace gold.
+
+#endif // !defined(GOLD_REDUCED_DEBUG_OUTPUT_H)
projects / deliverable / binutils-gdb.git / commitdiff
