[PATCH] gold: add incremental input structures definitions

[Mikolaj Zalewski <mikolajz at google dot com>]

  This patch adds some of the structures needed by incremental
linking. It has no effect yet, but I wanted to show it already. I have
chosen the next available SHT_ - is it OK, or should they be chosen
with care? As the incremental linking is specific to our linker, the
structures should go to gold/, or should they go to elfcpp/?
  If I understand, the design assumes that the command line is stored
as one string. Wouldn't it be easier to store it as a vector of
strings? This could make it easier to remove the --incremental-*
options.

2009-02-27  Mikolaj Zalewski  <mikolajz@google.com>

	* elfcpp/elfcpp.h: Add SHT_GNU_INCREMENTAL_INPUTS
	* gold/Makefile.in: Add incremental.cc
	* gold/Makefile.am: Add incremental.cc
	* gold/incremental.cc: New file
	* include/elf/common.h: Add SHT_GNU_INCREMENTAL_INPUTS

From 475b43e518d187a9a8398b8ef10e0afd65c8314d Mon Sep 17 00:00:00 2001
From: Mikolaj Zalewski <mikolajz@google.com>
Date: Fri, 27 Feb 2009 15:10:26 +0100
Subject: [PATCH] gold: add incremental input structures definitions

---
 elfcpp/elfcpp.h      |    6 ++-
 gold/Makefile.am     |    1 +
 gold/Makefile.in     |   17 ++++---
 gold/incremental.cc  |  146 ++++++++++++++++++++++++++++++++++++++++++++++++++
 include/elf/common.h |    1 +
 5 files changed, 162 insertions(+), 9 deletions(-)
 create mode 100644 gold/incremental.cc

diff --git a/elfcpp/elfcpp.h b/elfcpp/elfcpp.h
index 46306e7..ddf9e54 100644
--- a/elfcpp/elfcpp.h
+++ b/elfcpp/elfcpp.h
@@ -4,7 +4,7 @@
 // Written by Ian Lance Taylor <iant@google.com>.
 
 // This file is part of elfcpp.
-   
+
 // This program is free software; you can redistribute it and/or
 // modify it under the terms of the GNU Library General Public License
 // as published by the Free Software Foundation; either version 2, or
@@ -351,6 +351,8 @@ enum SHT
   SHT_LOUSER = 0x80000000,
   SHT_HIUSER = 0xffffffff,
   // The remaining values are not in the standard.
+  // Incremental build data.
+  SHT_GNU_INCREMENTAL_INPUTS = 0x6ffffff5,
   // Object attributes.
   SHT_GNU_ATTRIBUTES = 0x6ffffff5,
   // GNU style dynamic hash table.
@@ -934,7 +936,7 @@ class Ehdr_write
   void
   put_e_type(Elf_Half v)
   { this->p_->e_type = Convert<16, big_endian>::convert_host(v); }
-  
+
   void
   put_e_machine(Elf_Half v)
   { this->p_->e_machine = Convert<16, big_endian>::convert_host(v); }
diff --git a/gold/Makefile.am b/gold/Makefile.am
index aab1528..36c88e7 100644
--- a/gold/Makefile.am
+++ b/gold/Makefile.am
@@ -51,6 +51,7 @@ CCFILES = \
         gc.cc \
 	gold.cc \
 	gold-threads.cc \
+	incremental.cc \
 	layout.cc \
 	mapfile.cc \
 	merge.cc \
diff --git a/gold/Makefile.in b/gold/Makefile.in
index 20ad5b4..1f816f0 100644
--- a/gold/Makefile.in
+++ b/gold/Makefile.in
@@ -80,13 +80,14 @@ am__objects_1 = archive.$(OBJEXT) binary.$(OBJEXT) common.$(OBJEXT) \
 	dirsearch.$(OBJEXT) dynobj.$(OBJEXT) dwarf_reader.$(OBJEXT) \
 	ehframe.$(OBJEXT) errors.$(OBJEXT) expression.$(OBJEXT) \
 	fileread.$(OBJEXT) gc.$(OBJEXT) gold.$(OBJEXT) \
-	gold-threads.$(OBJEXT) layout.$(OBJEXT) mapfile.$(OBJEXT) \
-	merge.$(OBJEXT) object.$(OBJEXT) options.$(OBJEXT) \
-	output.$(OBJEXT) parameters.$(OBJEXT) plugin.$(OBJEXT) \
-	readsyms.$(OBJEXT) reduced_debug_output.$(OBJEXT) \
-	reloc.$(OBJEXT) resolve.$(OBJEXT) script-sections.$(OBJEXT) \
-	script.$(OBJEXT) stringpool.$(OBJEXT) symtab.$(OBJEXT) \
-	target-select.$(OBJEXT) version.$(OBJEXT) workqueue.$(OBJEXT) \
+	gold-threads.$(OBJEXT) incremental.$(OBJEXT) layout.$(OBJEXT) \
+	mapfile.$(OBJEXT) merge.$(OBJEXT) object.$(OBJEXT) \
+	options.$(OBJEXT) output.$(OBJEXT) parameters.$(OBJEXT) \
+	plugin.$(OBJEXT) readsyms.$(OBJEXT) \
+	reduced_debug_output.$(OBJEXT) reloc.$(OBJEXT) \
+	resolve.$(OBJEXT) script-sections.$(OBJEXT) script.$(OBJEXT) \
+	stringpool.$(OBJEXT) symtab.$(OBJEXT) target-select.$(OBJEXT) \
+	version.$(OBJEXT) workqueue.$(OBJEXT) \
 	workqueue-threads.$(OBJEXT)
 am__objects_2 =
 am__objects_3 = yyscript.$(OBJEXT)
@@ -333,6 +334,7 @@ CCFILES = \
         gc.cc \
 	gold.cc \
 	gold-threads.cc \
+	incremental.cc \
 	layout.cc \
 	mapfile.cc \
 	merge.cc \
@@ -552,6 +554,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/gold-threads.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/gold.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/i386.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/incremental.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/layout.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/main.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/mapfile.Po@am__quote@
diff --git a/gold/incremental.cc b/gold/incremental.cc
new file mode 100644
index 0000000..bd26bcd
--- /dev/null
+++ b/gold/incremental.cc
@@ -0,0 +1,146 @@
+// 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 "elfcpp.h"
+
+using elfcpp::Convert;
+
+namespace gold {
+
+// Version information. Will change frequently during the development, later
+// we could think about backward (and forward?) compatibility.
+const int INCREMENTAL_LINK_VERSION = 1;
+
+namespace internal {
+
+// Header of the .gnu_incremental_input section.
+struct Incremental_input_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_input_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_usec;
+
+  // Type of the input entry.
+  elfcpp::Elf_Half input_type;
+
+  // Padding.
+  elfcpp::Elf_Half reserved;
+};
+
+}
+
+// Accessors.
+
+// See internal::Incremental_input_header for fields descriptions.
+template<int size, bool big_endian>
+class Incremental_input_header_write
+{
+ public:
+  Incremental_input_header_write(unsigned char *p)
+    : p_(reinterpret_cast<internal::Incremental_input_header_data>(p))
+  { }
+
+  void
+  put_version(elfcpp::Elf_Word v)
+  { this->p_->version = Convert<32, big_endian>::convert_host(v); }
+
+  void
+  input_file_count(elfcpp::Elf_Word v)
+  { this->p_->input_file_count = Convert<32, big_endian>::convert_host(v); }
+
+  void
+  command_line_offset(elfcpp::Elf_Word v)
+  { this->p_->command_line_offset = Convert<32, big_endian>::convert_host(v); }
+
+  void
+  reserved(elfcpp::Elf_Word v)
+  { this->p_->reserved = Convert<32, big_endian>::convert_host(v); }
+
+ private:
+  internal::Incremental_input_header_data* p_;
+};
+
+// See internal::Incremental_input_entry for fields descriptions.
+template<int size, bool big_endian>
+class Incremental_input_entry_write
+{
+ public:
+  Incremental_input_entry_write(unsigned char *p)
+    : p_(reinterpret_cast<internal::Incremental_input_entry_data>(p))
+  { }
+
+  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_Word v)
+  { this->p_->timestamp_sec = Convert<32, big_endian>::convert_host(v); }
+
+  void
+  put_timestamp_usec(elfcpp::Elf_Word v)
+  { this->p_->timestamp_usec = 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_input_entry_data* p_;
+};
+
+
+}
diff --git a/include/elf/common.h b/include/elf/common.h
index 557c650..09d6d54 100644
--- a/include/elf/common.h
+++ b/include/elf/common.h
@@ -394,6 +394,7 @@
 #define SHT_LOOS	0x60000000	/* First of OS specific semantics */
 #define SHT_HIOS	0x6fffffff	/* Last of OS specific semantics */
 
+#define SHT_GNU_INCREMENTAL_INPUTS 0x6ffffff4   /* incremental build data */
 #define SHT_GNU_ATTRIBUTES 0x6ffffff5	/* Object attributes */
 #define SHT_GNU_HASH	0x6ffffff6	/* GNU style symbol hash table */
 #define SHT_GNU_LIBLIST	0x6ffffff7	/* List of prelink dependencies */
-- 
1.5.4.5