--- /dev/null
+// inremental.cc -- incremental linking support for gold
+
+// Copyright 2009 Free Software Foundation, Inc.
+// Written by Mikolaj Zalewski <mikolajz@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 <cstdarg>
+
+#include "elfcpp.h"
+#include "output.h"
+#include "incremental.h"
+#include "archive.h"
+#include "output.h"
+#include "target-select.h"
+
+using elfcpp::Convert;
+
+namespace gold {
+
+// Version information. Will change frequently during the development, later
+// we could think about backward (and forward?) compatibility.
+const unsigned int INCREMENTAL_LINK_VERSION = 1;
+
+namespace internal {
+
+// Header of the .gnu_incremental_input section.
+struct Incremental_inputs_header_data
+{
+ // Incremental linker version.
+ elfcpp::Elf_Word version;
+
+ // Numer of input files in the link.
+ elfcpp::Elf_Word input_file_count;
+
+ // Offset of command line options in .gnu_incremental_strtab.
+ elfcpp::Elf_Word command_line_offset;
+
+ // Padding.
+ elfcpp::Elf_Word reserved;
+};
+
+// Data stored in .gnu_incremental_input after the header for each of the
+// Incremental_input_header_data::input_file_count input entries.
+struct Incremental_inputs_entry_data
+{
+ // Offset of file name in .gnu_incremental_strtab section.
+ elfcpp::Elf_Word filename_offset;
+
+ // Offset of data in .gnu_incremental_input.
+ elfcpp::Elf_Word data_offset;
+
+ // Timestamp (in seconds).
+ elfcpp::Elf_Xword timestamp_sec;
+
+ // Nano-second part of timestamp (if supported).
+ elfcpp::Elf_Word timestamp_nsec;
+
+ // Type of the input entry.
+ elfcpp::Elf_Half input_type;
+
+ // Padding.
+ elfcpp::Elf_Half reserved;
+};
+
+}
+
+// Accessors.
+
+// Reader class for .gnu_incremental_inputs header. See
+// internal::Incremental_input_header for fields descriptions.
+
+template<int size, bool big_endian>
+class Incremental_inputs_header
+{
+ public:
+ Incremental_inputs_header(const unsigned char *p)
+ : p_(reinterpret_cast<const internal::Incremental_inputs_header_data*>(p))
+ { }
+
+ static const int data_size = sizeof(internal::Incremental_inputs_header_data);
+
+ elfcpp::Elf_Word
+ get_version() const
+ { return Convert<32, big_endian>::convert_host(this->p_->version); }
+
+ elfcpp::Elf_Word
+ get_input_file_count() const
+ { return Convert<32, big_endian>::convert_host(this->p_->input_file_count); }
+
+ elfcpp::Elf_Word
+ get_command_line_offset() const
+ { return Convert<32, big_endian>::convert_host(this->p_->command_line_offset); }
+
+ elfcpp::Elf_Word
+ get_reserved() const
+ { return Convert<32, big_endian>::convert_host(this->p_->reserved); }
+
+ private:
+ const internal::Incremental_inputs_header_data* p_;
+};
+
+// Writer class for .gnu_incremental_inputs header. See
+// internal::Incremental_input_header for fields descriptions.
+
+template<int size, bool big_endian>
+class Incremental_inputs_header_write
+{
+ public:
+ Incremental_inputs_header_write(unsigned char *p)
+ : p_(reinterpret_cast<internal::Incremental_inputs_header_data*>(p))
+ { }
+
+ static const int data_size = sizeof(internal::Incremental_inputs_header_data);
+
+ void
+ put_version(elfcpp::Elf_Word v)
+ { this->p_->version = Convert<32, big_endian>::convert_host(v); }
+
+ void
+ put_input_file_count(elfcpp::Elf_Word v)
+ { this->p_->input_file_count = Convert<32, big_endian>::convert_host(v); }
+
+ void
+ put_command_line_offset(elfcpp::Elf_Word v)
+ { this->p_->command_line_offset = Convert<32, big_endian>::convert_host(v); }
+
+ void
+ put_reserved(elfcpp::Elf_Word v)
+ { this->p_->reserved = Convert<32, big_endian>::convert_host(v); }
+
+ private:
+ internal::Incremental_inputs_header_data* p_;
+};
+
+// Reader class for an .gnu_incremental_inputs entry. See
+// internal::Incremental_input_entry for fields descriptions.
+template<int size, bool big_endian>
+class Incremental_inputs_entry
+{
+ public:
+ Incremental_inputs_entry(const unsigned char *p)
+ : p_(reinterpret_cast<const internal::Incremental_inputs_entry_data*>(p))
+ { }
+
+ static const int data_size = sizeof(internal::Incremental_inputs_entry_data);
+
+ elfcpp::Elf_Word
+ get_filename_offset(elfcpp::Elf_Word v)
+ { return Convert<32, big_endian>::convert_host(this->p_->filename_offset); }
+
+ elfcpp::Elf_Word
+ get_data_offset(elfcpp::Elf_Word v)
+ { return Convert<32, big_endian>::convert_host(this->p_->data_offset); }
+
+ elfcpp::Elf_Xword
+ get_timestamp_sec(elfcpp::Elf_Xword v)
+ { return Convert<64, big_endian>::convert_host(this->p_->timestamp_sec); }
+
+ elfcpp::Elf_Word
+ get_timestamp_nsec(elfcpp::Elf_Word v)
+ { return Convert<32, big_endian>::convert_host(this->p_->timestamp_nsec); }
+
+ elfcpp::Elf_Word
+ get_input_type(elfcpp::Elf_Word v)
+ { return Convert<32, big_endian>::convert_host(this->p_->input_type); }
+
+ elfcpp::Elf_Word
+ get_reserved(elfcpp::Elf_Word v)
+ { return Convert<32, big_endian>::convert_host(this->p_->reserved); }
+
+ private:
+ const internal::Incremental_inputs_entry_data* p_;
+};
+
+// Writer class for an .gnu_incremental_inputs entry. See
+// internal::Incremental_input_entry for fields descriptions.
+template<int size, bool big_endian>
+class Incremental_inputs_entry_write
+{
+ public:
+ Incremental_inputs_entry_write(unsigned char *p)
+ : p_(reinterpret_cast<internal::Incremental_inputs_entry_data*>(p))
+ { }
+
+ static const int data_size = sizeof(internal::Incremental_inputs_entry_data);
+
+ void
+ put_filename_offset(elfcpp::Elf_Word v)
+ { this->p_->filename_offset = Convert<32, big_endian>::convert_host(v); }
+
+ void
+ put_data_offset(elfcpp::Elf_Word v)
+ { this->p_->data_offset = Convert<32, big_endian>::convert_host(v); }
+
+ void
+ put_timestamp_sec(elfcpp::Elf_Xword v)
+ { this->p_->timestamp_sec = Convert<64, big_endian>::convert_host(v); }
+
+ void
+ put_timestamp_nsec(elfcpp::Elf_Word v)
+ { this->p_->timestamp_nsec = Convert<32, big_endian>::convert_host(v); }
+
+ void
+ put_input_type(elfcpp::Elf_Word v)
+ { this->p_->input_type = Convert<32, big_endian>::convert_host(v); }
+
+ void
+ put_reserved(elfcpp::Elf_Word v)
+ { this->p_->reserved = Convert<32, big_endian>::convert_host(v); }
+
+ private:
+ internal::Incremental_inputs_entry_data* p_;
+};
+
+// Inform the user why we don't do an incremental link. Not called in
+// the obvious case of missing output file. TODO: Is this helpful?
+
+void
+vexplain_no_incremental(const char* format, va_list args)
+{
+ char* buf = NULL;
+ if (vasprintf(&buf, format, args) < 0)
+ gold_nomem();
+ gold_info(_("the link might take longer: "
+ "cannot perform incremental link: %s"), buf);
+ free(buf);
+}
+
+void
+explain_no_incremental(const char* format, ...)
+{
+ va_list args;
+ va_start(args, format);
+ vexplain_no_incremental(format, args);
+ va_end(args);
+}
+
+// Report an error.
+
+void
+Incremental_binary::error(const char* format, ...) const
+{
+ va_list args;
+ va_start(args, format);
+ // Current code only checks if the file can be used for incremental linking,
+ // so errors shouldn't fail the build, but only result in a fallback to a
+ // full build.
+ // TODO: when we implement incremental editing of the file, we may need a
+ // flag that will cause errors to be treated seriously.
+ vexplain_no_incremental(format, args);
+ va_end(args);
+}
+
+template<int size, bool big_endian>
+bool
+Sized_incremental_binary<size, big_endian>::do_find_incremental_inputs_section(
+ Location* location,
+ unsigned int* strtab_shndx)
+{
+ unsigned int shndx = this->elf_file_.find_section_by_type(
+ elfcpp::SHT_GNU_INCREMENTAL_INPUTS);
+ if (shndx == elfcpp::SHN_UNDEF) // Not found.
+ return false;
+ *strtab_shndx = this->elf_file_.section_link(shndx);
+ *location = this->elf_file_.section_contents(shndx);
+ return true;
+}
+
+template<int size, bool big_endian>
+bool
+Sized_incremental_binary<size, big_endian>::do_check_inputs(
+ Incremental_inputs* incremental_inputs)
+{
+ const int entry_size =
+ Incremental_inputs_entry_write<size, big_endian>::data_size;
+ const int header_size =
+ Incremental_inputs_header_write<size, big_endian>::data_size;
+
+ unsigned int strtab_shndx;
+ Location location;
+
+ if (!do_find_incremental_inputs_section(&location, &strtab_shndx))
+ {
+ explain_no_incremental(_("no incremental data from previous build"));
+ return false;
+ }
+ if (location.data_size < header_size
+ || strtab_shndx >= this->elf_file_.shnum()
+ || this->elf_file_.section_type(strtab_shndx) != elfcpp::SHT_STRTAB)
+ {
+ explain_no_incremental(_("invalid incremental build data"));
+ return false;
+ }
+
+ Location strtab_location(this->elf_file_.section_contents(strtab_shndx));
+ View data_view(view(location));
+ View strtab_view(view(strtab_location));
+ elfcpp::Elf_strtab strtab(strtab_view.data(), strtab_location.data_size);
+ Incremental_inputs_header<size, big_endian> header(data_view.data());
+
+ if (header.get_version() != INCREMENTAL_LINK_VERSION)
+ {
+ explain_no_incremental(_("different version of incremental build data"));
+ return false;
+ }
+
+ const char* command_line;
+ // We divide instead of multiplying to make sure there is no integer
+ // overflow.
+ size_t max_input_entries = (location.data_size - header_size) / entry_size;
+ if (header.get_input_file_count() > max_input_entries
+ || !strtab.get_c_string(header.get_command_line_offset(), &command_line))
+ {
+ explain_no_incremental(_("invalid incremental build data"));
+ return false;
+ }
+
+ if (incremental_inputs->command_line() != command_line)
+ {
+ explain_no_incremental(_("command line changed"));
+ return false;
+ }
+
+ // TODO: compare incremental_inputs->inputs() with entries in data_view.
+ return true;
+}
+
+namespace
+{
+
+// Create a Sized_incremental_binary object of the specified size and
+// endianness. Fails if the target architecture is not supported.
+
+template<int size, bool big_endian>
+Incremental_binary*
+make_sized_incremental_binary(Output_file* file,
+ const elfcpp::Ehdr<size, big_endian>& ehdr)
+{
+ Target* target = select_target(ehdr.get_e_machine(), size, big_endian,
+ ehdr.get_e_ident()[elfcpp::EI_OSABI],
+ ehdr.get_e_ident()[elfcpp::EI_ABIVERSION]);
+ if (target == NULL)
+ {
+ explain_no_incremental(_("unsupported ELF machine number %d"),
+ ehdr.get_e_machine());
+ return NULL;
+ }
+
+ return new Sized_incremental_binary<size, big_endian>(file, ehdr, target);
+}
+
+} // End of anonymous namespace.
+
+// Create an Incremental_binary object for FILE. Returns NULL is this is not
+// possible, e.g. FILE is not an ELF file or has an unsupported target. FILE
+// should be opened.
+
+Incremental_binary*
+open_incremental_binary(Output_file* file)
+{
+ off_t filesize = file->filesize();
+ int want = elfcpp::Elf_recognizer::max_header_size;
+ if (filesize < want)
+ want = filesize;
+
+ const unsigned char* p = file->get_input_view(0, want);
+ if (!elfcpp::Elf_recognizer::is_elf_file(p, want))
+ {
+ explain_no_incremental(_("output is not an ELF file."));
+ return NULL;
+ }
+
+ int size;
+ bool big_endian;
+ std::string error;
+ if (!elfcpp::Elf_recognizer::is_valid_header(p, want, &size, &big_endian,
+ &error))
+ {
+ explain_no_incremental(error.c_str());
+ return NULL;
+ }
+
+ Incremental_binary* result = NULL;
+ if (size == 32)
+ {
+ if (big_endian)
+ {
+#ifdef HAVE_TARGET_32_BIG
+ result = make_sized_incremental_binary<32, true>(
+ file, elfcpp::Ehdr<32, true>(p));
+#else
+ explain_no_incremental(_("unsupported file: 32-bit, big-endian"));
+#endif
+ }
+ else
+ {
+#ifdef HAVE_TARGET_32_LITTLE
+ result = make_sized_incremental_binary<32, false>(
+ file, elfcpp::Ehdr<32, false>(p));
+#else
+ explain_no_incremental(_("unsupported file: 32-bit, little-endian"));
+#endif
+ }
+ }
+ else if (size == 64)
+ {
+ if (big_endian)
+ {
+#ifdef HAVE_TARGET_64_BIG
+ result = make_sized_incremental_binary<64, true>(
+ file, elfcpp::Ehdr<64, true>(p));
+#else
+ explain_no_incremental(_("unsupported file: 64-bit, big-endian"));
+#endif
+ }
+ else
+ {
+#ifdef HAVE_TARGET_64_LITTLE
+ result = make_sized_incremental_binary<64, false>(
+ file, elfcpp::Ehdr<64, false>(p));
+#else
+ explain_no_incremental(_("unsupported file: 64-bit, little-endian"));
+#endif
+ }
+ }
+ else
+ gold_unreachable();
+
+ return result;
+}
+
+// Analyzes the output file to check if incremental linking is possible and
+// (to be done) what files need to be relinked.
+
+bool
+Incremental_checker::can_incrementally_link_output_file()
+{
+ Output_file output(this->output_name_);
+ if (!output.open_for_modification())
+ return false;
+ Incremental_binary* binary = open_incremental_binary(&output);
+ if (binary == NULL)
+ return false;
+ return binary->check_inputs(this->incremental_inputs_);
+}
+
+// Add the command line to the string table, setting
+// command_line_key_. In incremental builds, the command line is
+// stored in .gnu_incremental_inputs so that the next linker run can
+// check if the command line options didn't change.
+
+void
+Incremental_inputs::report_command_line(int argc, const char* const* argv)
+{
+ // Always store 'gold' as argv[0] to avoid a full relink if the user used a
+ // different path to the linker.
+ std::string args("gold");
+ // Copied from collect_argv in main.cc.
+ for (int i = 1; i < argc; ++i)
+ {
+ // Adding/removing these options should result in a full relink.
+ if (strcmp(argv[i], "--incremental-changed") == 0
+ || strcmp(argv[i], "--incremental-unchanged") == 0
+ || strcmp(argv[i], "--incremental-unknown") == 0)
+ continue;
+
+ args.append(" '");
+ // Now append argv[i], but with all single-quotes escaped
+ const char* argpos = argv[i];
+ while (1)
+ {
+ const int len = strcspn(argpos, "'");
+ args.append(argpos, len);
+ if (argpos[len] == '\0')
+ break;
+ args.append("'\"'\"'");
+ argpos += len + 1;
+ }
+ args.append("'");
+ }
+
+ this->command_line_ = args;
+ this->strtab_->add(this->command_line_.c_str(), false,
+ &this->command_line_key_);
+}
+
+// Record that the input argument INPUT is an achive ARCHIVE. This is
+// called by Read_symbols after finding out the type of the file.
+
+void
+Incremental_inputs::report_archive(const Input_argument* input,
+ Archive* archive)
+{
+ Hold_lock hl(*this->lock_);
+
+ Input_info info;
+ info.type = INCREMENTAL_INPUT_ARCHIVE;
+ info.archive = archive;
+ info.mtime = archive->file().get_mtime();
+ this->inputs_map_.insert(std::make_pair(input, info));
+}
+
+// Record that the input argument INPUT is an object OBJ. This is
+// called by Read_symbols after finding out the type of the file.
+
+void
+Incremental_inputs::report_object(const Input_argument* input,
+ Object* obj)
+{
+ Hold_lock hl(*this->lock_);
+
+ Input_info info;
+ info.type = (obj->is_dynamic()
+ ? INCREMENTAL_INPUT_SHARED_LIBRARY
+ : INCREMENTAL_INPUT_OBJECT);
+ info.object = obj;
+ info.mtime = obj->input_file()->file().get_mtime();
+ this->inputs_map_.insert(std::make_pair(input, info));
+}
+
+// Record that the input argument INPUT is an script SCRIPT. This is
+// called by read_script after parsing the script and reading the list
+// of inputs added by this script.
+
+void
+Incremental_inputs::report_script(const Input_argument* input,
+ Timespec mtime,
+ Script_info* script)
+{
+ Hold_lock hl(*this->lock_);
+
+ Input_info info;
+ info.type = INCREMENTAL_INPUT_SCRIPT;
+ info.script = script;
+ info.mtime = mtime;
+ this->inputs_map_.insert(std::make_pair(input, info));
+}
+
+// Compute indexes in the order in which the inputs should appear in
+// .gnu_incremental_inputs. This needs to be done after all the
+// scripts are parsed. The function is first called for the command
+// line inputs arguments and may call itself recursively for e.g. a
+// list of elements of a group or a list of inputs added by a script.
+// The [BEGIN; END) interval to analyze and *INDEX is the current
+// value of the index (that will be updated).
+
+void
+Incremental_inputs::finalize_inputs(
+ Input_argument_list::const_iterator begin,
+ Input_argument_list::const_iterator end,
+ unsigned int* index)
+{
+ for (Input_argument_list::const_iterator p = begin; p != end; ++p)
+ {
+ if (p->is_group())
+ {
+ finalize_inputs(p->group()->begin(), p->group()->end(), index);
+ continue;
+ }
+
+ Inputs_info_map::iterator it = this->inputs_map_.find(&(*p));
+ // TODO: turn it into an assert when the code will be more stable.
+ if (it == this->inputs_map_.end())
+ {
+ gold_error("internal error: %s: incremental build info not provided",
+ (p->is_file() ? p->file().name() : "[group]"));
+ continue;
+ }
+ Input_info* info = &it->second;
+ info->index = *index;
+ (*index)++;
+ this->strtab_->add(p->file().name(), false, &info->filename_key);
+ if (info->type == INCREMENTAL_INPUT_SCRIPT)
+ {
+ finalize_inputs(info->script->inputs()->begin(),
+ info->script->inputs()->end(),
+ index);
+ }
+ }
+}
+
+// Finalize the incremental link information. Called from
+// Layout::finalize.
+
+void
+Incremental_inputs::finalize()
+{
+ unsigned int index = 0;
+ finalize_inputs(this->inputs_->begin(), this->inputs_->end(), &index);
+
+ // Sanity check.
+ for (Inputs_info_map::const_iterator p = this->inputs_map_.begin();
+ p != this->inputs_map_.end();
+ ++p)
+ {
+ gold_assert(p->second.filename_key != 0);
+ }
+
+ this->strtab_->set_string_offsets();
+}
+
+// Create the content of the .gnu_incremental_inputs section.
+
+Output_section_data*
+Incremental_inputs::create_incremental_inputs_section_data()
+{
+ switch (parameters->size_and_endianness())
+ {
+#ifdef HAVE_TARGET_32_LITTLE
+ case Parameters::TARGET_32_LITTLE:
+ return this->sized_create_inputs_section_data<32, false>();
+#endif
+#ifdef HAVE_TARGET_32_BIG
+ case Parameters::TARGET_32_BIG:
+ return this->sized_create_inputs_section_data<32, true>();
+#endif
+#ifdef HAVE_TARGET_64_LITTLE
+ case Parameters::TARGET_64_LITTLE:
+ return this->sized_create_inputs_section_data<64, false>();
+#endif
+#ifdef HAVE_TARGET_64_BIG
+ case Parameters::TARGET_64_BIG:
+ return this->sized_create_inputs_section_data<64, true>();
+#endif
+ default:
+ gold_unreachable();
+ }
+}
+
+// Sized creation of .gnu_incremental_inputs section.
+
+template<int size, bool big_endian>
+Output_section_data*
+Incremental_inputs::sized_create_inputs_section_data()
+{
+ const int entry_size =
+ Incremental_inputs_entry_write<size, big_endian>::data_size;
+ const int header_size =
+ Incremental_inputs_header_write<size, big_endian>::data_size;
+
+ unsigned int sz = header_size + entry_size * this->inputs_map_.size();
+ unsigned char* buffer = new unsigned char[sz];
+ unsigned char* inputs_base = buffer + header_size;
+
+ Incremental_inputs_header_write<size, big_endian> header_writer(buffer);
+ gold_assert(this->command_line_key_ > 0);
+ int cmd_offset = this->strtab_->get_offset_from_key(this->command_line_key_);
+
+ header_writer.put_version(INCREMENTAL_LINK_VERSION);
+ header_writer.put_input_file_count(this->inputs_map_.size());
+ header_writer.put_command_line_offset(cmd_offset);
+ header_writer.put_reserved(0);
+
+ for (Inputs_info_map::const_iterator it = this->inputs_map_.begin();
+ it != this->inputs_map_.end();
+ ++it)
+ {
+ gold_assert(it->second.index < this->inputs_map_.size());
+
+ unsigned char* entry_buffer =
+ inputs_base + it->second.index * entry_size;
+ Incremental_inputs_entry_write<size, big_endian> entry(entry_buffer);
+ int filename_offset =
+ this->strtab_->get_offset_from_key(it->second.filename_key);
+ entry.put_filename_offset(filename_offset);
+ // TODO: add per input data and timestamp. Currently we store
+ // an out-of-bounds offset for future version of gold to reject
+ // such an incremental_inputs section.
+ entry.put_data_offset(0xffffffff);
+ entry.put_timestamp_sec(it->second.mtime.seconds);
+ entry.put_timestamp_nsec(it->second.mtime.nanoseconds);
+ entry.put_input_type(it->second.type);
+ entry.put_reserved(0);
+ }
+
+ return new Output_data_const_buffer(buffer, sz, 8,
+ "** incremental link inputs list");
+}
+
+// Instantiate the templates we need.
+
+#ifdef HAVE_TARGET_32_LITTLE
+template
+class Sized_incremental_binary<32, false>;
+#endif
+
+#ifdef HAVE_TARGET_32_BIG
+template
+class Sized_incremental_binary<32, true>;
+#endif
+
+#ifdef HAVE_TARGET_64_LITTLE
+template
+class Sized_incremental_binary<64, false>;
+#endif
+
+#ifdef HAVE_TARGET_64_BIG
+template
+class Sized_incremental_binary<64, true>;
+#endif
+
+} // End namespace gold.
projects / msp430-binutils.git / blobdiff