* elf32-spu.c (build_stub): Fix malloc under-allocation.
[binutils.git] / gold / icf.h
blobf1581375c3b52a35bf4a261adc58807a1ad46abc
1 // icf.h -- Identical Code Folding
3 // Copyright 2009, 2010 Free Software Foundation, Inc.
4 // Written by Sriraman Tallam <tmsriram@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
23 #ifndef GOLD_ICF_H
24 #define GOLD_ICF_H
26 #include <vector>
28 #include "elfcpp.h"
29 #include "symtab.h"
30 #include "object.h"
32 namespace gold
35 class Object;
36 class Input_objects;
37 class Symbol_table;
39 class Icf
41 public:
42 typedef std::vector<Section_id> Sections_reachable_info;
43 typedef std::vector<Symbol*> Symbol_info;
44 typedef std::vector<std::pair<long long, long long> > Addend_info;
45 typedef std::vector<uint64_t> Offset_info;
46 typedef std::vector<unsigned int> Reloc_addend_size_info;
47 typedef Unordered_map<Section_id,
48 unsigned int,
49 Section_id_hash> Uniq_secn_id_map;
50 typedef Unordered_set<Section_id, Section_id_hash> Secn_fptr_taken_set;
52 typedef struct
54 // This stores the section corresponding to the reloc.
55 Sections_reachable_info section_info;
56 // This stores the symbol corresponding to the reloc.
57 Symbol_info symbol_info;
58 // This stores the symbol value and the addend for a reloc.
59 Addend_info addend_info;
60 Offset_info offset_info;
61 Reloc_addend_size_info reloc_addend_size_info;
62 } Reloc_info;
64 typedef Unordered_map<Section_id, Reloc_info,
65 Section_id_hash> Reloc_info_list;
67 Icf()
68 : id_section_(), section_id_(), kept_section_id_(),
69 fptr_section_id_(),
70 num_tracked_relocs(NULL), icf_ready_(false),
71 reloc_info_list_()
72 { }
74 // Returns the kept folded identical section corresponding to
75 // dup_obj and dup_shndx.
76 Section_id
77 get_folded_section(Object* dup_obj, unsigned int dup_shndx);
79 // Forms groups of identical sections where the first member
80 // of each group is the kept section during folding.
81 void
82 find_identical_sections(const Input_objects* input_objects,
83 Symbol_table* symtab);
85 // This is set when ICF has been run and the groups of
86 // identical sections have been formed.
87 void
88 icf_ready()
89 { this->icf_ready_ = true; }
91 // Returns true if ICF has been run.
92 bool
93 is_icf_ready()
94 { return this->icf_ready_; }
96 // Unfolds the section denoted by OBJ and SHNDX if folded.
97 void
98 unfold_section(Object* obj, unsigned int shndx);
100 // Returns the kept section corresponding to the
101 // given section.
102 bool
103 is_section_folded(Object* obj, unsigned int shndx);
105 // Given an object and a section index, this returns true if the
106 // pointer of the function defined in this section is taken.
107 bool
108 section_has_function_pointers(Object* obj, unsigned int shndx)
110 return (this->fptr_section_id_.find(Section_id(obj, shndx))
111 != this->fptr_section_id_.end());
114 // Records that a pointer of the function defined in this section
115 // is taken.
116 void
117 set_section_has_function_pointers(Object* obj, unsigned int shndx)
119 this->fptr_section_id_.insert(Section_id(obj, shndx));
122 // Checks if the section_name should be searched for relocs
123 // corresponding to taken function pointers. Ignores eh_frame
124 // and vtable sections.
125 inline bool
126 check_section_for_function_pointers(const std::string& section_name,
127 Target* target)
129 return (parameters->options().icf_safe_folding()
130 && target->can_check_for_function_pointers()
131 && target->section_may_have_icf_unsafe_pointers(
132 section_name.c_str()));
135 // Returns a map of a section to info (Reloc_info) about its relocations.
136 Reloc_info_list&
137 reloc_info_list()
138 { return this->reloc_info_list_; }
140 // Returns a mapping of each section to a unique integer.
141 Uniq_secn_id_map&
142 section_to_int_map()
143 { return this->section_id_; }
145 private:
147 // Maps integers to sections.
148 std::vector<Section_id> id_section_;
149 // Does the reverse.
150 Uniq_secn_id_map section_id_;
151 // Given a section id, this maps it to the id of the kept
152 // section. If the id's are the same then this section is
153 // not folded.
154 std::vector<unsigned int> kept_section_id_;
155 // Given a section id, this says if the pointer to this
156 // function is taken in which case it is dangerous to fold
157 // this function.
158 Secn_fptr_taken_set fptr_section_id_;
159 unsigned int* num_tracked_relocs;
160 // Flag to indicate if ICF has been run.
161 bool icf_ready_;
162 // This list is populated by gc_process_relocs in gc.h.
163 Reloc_info_list reloc_info_list_;
166 // This function returns true if this section corresponds to a function that
167 // should be considered by icf as a possible candidate for folding. Some
168 // earlier gcc versions, like 4.0.3, put constructors and destructors in
169 // .gnu.linkonce.t sections and hence should be included too.
170 inline bool
171 is_section_foldable_candidate(const std::string& section_name)
173 const char* section_name_cstr = section_name.c_str();
174 return (is_prefix_of(".text", section_name_cstr)
175 || is_prefix_of(".gnu.linkonce.t", section_name_cstr));
178 } // End of namespace gold.
180 #endif