upload android base code part8

android/toolchain/binutils/binutils-2.25/gold/icf.h

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+// icf.h --  Identical Code Folding
+
+// Copyright (C) 2009-2014 Free Software Foundation, Inc.
+// Written by Sriraman Tallam <tmsriram@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.
+
+#ifndef GOLD_ICF_H
+#define GOLD_ICF_H
+
+#include <vector>
+
+#include "elfcpp.h"
+#include "symtab.h"
+#include "object.h"
+
+namespace gold
+{
+
+class Object;
+class Input_objects;
+class Symbol_table;
+
+class Icf
+{
+ public:
+  typedef std::vector<Section_id> Sections_reachable_info;
+  typedef std::vector<Symbol*> Symbol_info;
+  typedef std::vector<std::pair<long long, long long> > Addend_info;
+  typedef std::vector<uint64_t> Offset_info;
+  typedef std::vector<unsigned int> Reloc_addend_size_info;
+  typedef Unordered_map<Section_id,
+                        unsigned int,
+                        Section_id_hash> Uniq_secn_id_map;
+  typedef Unordered_set<Section_id, Section_id_hash> Secn_fptr_taken_set;
+
+  typedef struct
+  {
+    // This stores the section corresponding to the reloc.
+    Sections_reachable_info section_info;
+    // This stores the symbol corresponding to the reloc.
+    Symbol_info symbol_info;
+    // This stores the symbol value and the addend for a reloc.
+    Addend_info addend_info;
+    Offset_info offset_info;
+    Reloc_addend_size_info reloc_addend_size_info;
+  } Reloc_info;
+
+  typedef Unordered_map<Section_id, Reloc_info,
+                        Section_id_hash> Reloc_info_list;
+
+  Icf()
+  : id_section_(), section_id_(), kept_section_id_(),
+    fptr_section_id_(),
+    icf_ready_(false),
+    reloc_info_list_()
+  { }
+
+  // Returns the kept folded identical section corresponding to
+  // dup_obj and dup_shndx.
+  Section_id
+  get_folded_section(Object* dup_obj, unsigned int dup_shndx);
+
+  // Forms groups of identical sections where the first member
+  // of each group is the kept section during folding.
+  void
+  find_identical_sections(const Input_objects* input_objects,
+                          Symbol_table* symtab);
+
+  // This is set when ICF has been run and the groups of
+  // identical sections have been formed.
+  void
+  icf_ready()
+  { this->icf_ready_ = true; }
+
+  // Returns true if ICF has been run.
+  bool
+  is_icf_ready()
+  { return this->icf_ready_; }
+
+  // Unfolds the section denoted by OBJ and SHNDX if folded.
+  void
+  unfold_section(Object* obj, unsigned int shndx);
+
+  // Returns the kept section corresponding to the
+  // given section.
+  bool
+  is_section_folded(Object* obj, unsigned int shndx);
+
+  // Given an object and a section index, this returns true if the
+  // pointer of the function defined in this section is taken.
+  bool
+  section_has_function_pointers(Object* obj, unsigned int shndx)
+  {
+    return (this->fptr_section_id_.find(Section_id(obj, shndx))
+            != this->fptr_section_id_.end());
+  }
+
+  // Records that a pointer of the function defined in this section
+  // is taken.
+  void
+  set_section_has_function_pointers(Object* obj, unsigned int shndx)
+  {
+    this->fptr_section_id_.insert(Section_id(obj, shndx));
+  }
+
+  // Checks if the section_name should be searched for relocs
+  // corresponding to taken function pointers.  Ignores eh_frame
+  // and vtable sections.
+  inline bool
+  check_section_for_function_pointers(const std::string& section_name,
+                                      Target* target)
+  {
+    return (parameters->options().icf_safe_folding()
+	    && target->can_check_for_function_pointers()
+	    && target->section_may_have_icf_unsafe_pointers(
+	        section_name.c_str()));
+  }
+
+  // Returns a map of a section to info (Reloc_info) about its relocations.
+  Reloc_info_list&
+  reloc_info_list()
+  { return this->reloc_info_list_; }
+
+  // Returns a mapping of each section to a unique integer.
+  Uniq_secn_id_map&
+  section_to_int_map()
+  { return this->section_id_; }
+
+ private:
+
+  // Maps integers to sections.
+  std::vector<Section_id> id_section_;
+  // Does the reverse.
+  Uniq_secn_id_map section_id_;
+  // Given a section id, this maps it to the id of the kept
+  // section.  If the id's are the same then this section is
+  // not folded.
+  std::vector<unsigned int> kept_section_id_;
+  // Given a section id, this says if the pointer to this
+  // function is taken in which case it is dangerous to fold
+  // this function.
+  Secn_fptr_taken_set fptr_section_id_;
+  // Flag to indicate if ICF has been run.
+  bool icf_ready_;
+  // This list is populated by gc_process_relocs in gc.h.
+  Reloc_info_list reloc_info_list_;
+};
+
+// This function returns true if this section corresponds to a function that
+// should be considered by icf as a possible candidate for folding.  Some
+// earlier gcc versions, like 4.0.3, put constructors and destructors in
+// .gnu.linkonce.t sections and hence should be included too.
+inline bool
+is_section_foldable_candidate(const std::string& section_name)
+{
+  const char* section_name_cstr = section_name.c_str();
+  return (is_prefix_of(".text", section_name_cstr)
+          || is_prefix_of(".gnu.linkonce.t", section_name_cstr));
+}
+
+} // End of namespace gold.
+
+#endif