diff options
Diffstat (limited to 'gold/output.cc')
| -rw-r--r-- | gold/output.cc | 161 |
1 files changed, 160 insertions, 1 deletions
diff --git a/gold/output.cc b/gold/output.cc index affc6f7..12268c9 100644 --- a/gold/output.cc +++ b/gold/output.cc @@ -36,6 +36,7 @@ #include "libiberty.h" +#include "dwarf.h" #include "parameters.h" #include "object.h" #include "symtab.h" @@ -1926,6 +1927,140 @@ Output_symtab_xindex::endian_do_write(unsigned char* const oview) } } +// Output_fill_debug_info methods. + +// Return the minimum size needed for a dummy compilation unit header. + +size_t +Output_fill_debug_info::do_minimum_hole_size() const +{ + // Compile unit header fields: unit_length, version, debug_abbrev_offset, + // address_size. + const size_t len = 4 + 2 + 4 + 1; + // For type units, add type_signature, type_offset. + if (this->is_debug_types_) + return len + 8 + 4; + return len; +} + +// Write a dummy compilation unit header to fill a hole in the +// .debug_info or .debug_types section. + +void +Output_fill_debug_info::do_write(Output_file* of, off_t off, size_t len) const +{ + gold_debug(DEBUG_INCREMENTAL, "fill_debug_info(%08lx, %08lx)", off, len); + + gold_assert(len >= this->do_minimum_hole_size()); + + unsigned char* const oview = of->get_output_view(off, len); + unsigned char* pov = oview; + + // Write header fields: unit_length, version, debug_abbrev_offset, + // address_size. + if (this->is_big_endian()) + { + elfcpp::Swap<32, true>::writeval(pov, len - 4); + elfcpp::Swap<16, true>::writeval(pov + 4, this->version); + elfcpp::Swap<32, true>::writeval(pov + 6, 0); + } + else + { + elfcpp::Swap<32, false>::writeval(pov, len - 4); + elfcpp::Swap<16, false>::writeval(pov + 4, this->version); + elfcpp::Swap<32, false>::writeval(pov + 6, 0); + } + pov += 4 + 2 + 4; + *pov++ = 4; + + // For type units, the additional header fields -- type_signature, + // type_offset -- can be filled with zeroes. + + // Fill the remainder of the free space with zeroes. The first + // zero should tell the consumer there are no DIEs to read in this + // compilation unit. + if (pov < oview + len) + memset(pov, 0, oview + len - pov); + + of->write_output_view(off, len, oview); +} + +// Output_fill_debug_line methods. + +// Return the minimum size needed for a dummy line number program header. + +size_t +Output_fill_debug_line::do_minimum_hole_size() const +{ + // Line number program header fields: unit_length, version, header_length, + // minimum_instruction_length, default_is_stmt, line_base, line_range, + // opcode_base, standard_opcode_lengths[], include_directories, filenames. + const size_t len = 4 + 2 + 4 + this->header_length; + return len; +} + +// Write a dummy line number program header to fill a hole in the +// .debug_line section. + +void +Output_fill_debug_line::do_write(Output_file* of, off_t off, size_t len) const +{ + gold_debug(DEBUG_INCREMENTAL, "fill_debug_line(%08lx, %08lx)", off, len); + + gold_assert(len >= this->do_minimum_hole_size()); + + unsigned char* const oview = of->get_output_view(off, len); + unsigned char* pov = oview; + + // Write header fields: unit_length, version, header_length, + // minimum_instruction_length, default_is_stmt, line_base, line_range, + // opcode_base, standard_opcode_lengths[], include_directories, filenames. + // We set the header_length field to cover the entire hole, so the + // line number program is empty. + if (this->is_big_endian()) + { + elfcpp::Swap<32, true>::writeval(pov, len - 4); + elfcpp::Swap<16, true>::writeval(pov + 4, this->version); + elfcpp::Swap<32, true>::writeval(pov + 6, len - (4 + 2 + 4)); + } + else + { + elfcpp::Swap<32, false>::writeval(pov, len - 4); + elfcpp::Swap<16, false>::writeval(pov + 4, this->version); + elfcpp::Swap<32, false>::writeval(pov + 6, len - (4 + 2 + 4)); + } + pov += 4 + 2 + 4; + *pov++ = 1; // minimum_instruction_length + *pov++ = 0; // default_is_stmt + *pov++ = 0; // line_base + *pov++ = 5; // line_range + *pov++ = 13; // opcode_base + *pov++ = 0; // standard_opcode_lengths[1] + *pov++ = 1; // standard_opcode_lengths[2] + *pov++ = 1; // standard_opcode_lengths[3] + *pov++ = 1; // standard_opcode_lengths[4] + *pov++ = 1; // standard_opcode_lengths[5] + *pov++ = 0; // standard_opcode_lengths[6] + *pov++ = 0; // standard_opcode_lengths[7] + *pov++ = 0; // standard_opcode_lengths[8] + *pov++ = 1; // standard_opcode_lengths[9] + *pov++ = 0; // standard_opcode_lengths[10] + *pov++ = 0; // standard_opcode_lengths[11] + *pov++ = 1; // standard_opcode_lengths[12] + *pov++ = 0; // include_directories (empty) + *pov++ = 0; // filenames (empty) + + // Some consumers don't check the header_length field, and simply + // start reading the line number program immediately following the + // header. For those consumers, we fill the remainder of the free + // space with DW_LNS_set_basic_block opcodes. These are effectively + // no-ops: the resulting line table program will not create any rows. + if (pov < oview + len) + memset(pov, elfcpp::DW_LNS_set_basic_block, oview + len - pov); + + of->write_output_view(off, len, oview); +} + // Output_section::Input_section methods. // Return the current data size. For an input section we store the size here. @@ -2158,6 +2293,7 @@ Output_section::Output_section(const char* name, elfcpp::Elf_Word type, checkpoint_(NULL), lookup_maps_(new Output_section_lookup_maps), free_list_(), + free_space_fill_(NULL), patch_space_(0) { // An unallocated section has no address. Forcing this means that @@ -2981,7 +3117,10 @@ Output_section::set_final_data_size() if (this->is_patch_space_allowed_ && parameters->incremental_full()) { double pct = parameters->options().incremental_patch(); - off_t extra = static_cast<off_t>(data_size * pct); + size_t extra = static_cast<size_t>(data_size * pct); + if (this->free_space_fill_ != NULL + && this->free_space_fill_->minimum_hole_size() > extra) + extra = this->free_space_fill_->minimum_hole_size(); off_t new_size = align_address(data_size + extra, this->addralign()); this->patch_space_ = new_size - data_size; gold_debug(DEBUG_INCREMENTAL, @@ -3515,6 +3654,26 @@ Output_section::do_write(Output_file* of) p->write(of); off = aligned_off + p->data_size(); } + + // For incremental links, fill in unused chunks in debug sections + // with dummy compilation unit headers. + if (this->free_space_fill_ != NULL) + { + for (Free_list::Const_iterator p = this->free_list_.begin(); + p != this->free_list_.end(); + ++p) + { + off_t off = p->start_; + size_t len = p->end_ - off; + this->free_space_fill_->write(of, this->offset() + off, len); + } + if (this->patch_space_ > 0) + { + off_t off = this->current_data_size_for_child() - this->patch_space_; + this->free_space_fill_->write(of, this->offset() + off, + this->patch_space_); + } + } } // If a section requires postprocessing, create the buffer to use. |