X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=gold%2Fmerge.h;h=47af24db07bedad0440e33a07997095c64655b00;hb=9ef9e6a6a0dd8f948708cb67c9afcfd0be40cb0a;hp=a64932180ec762f22a83492f6e5782c00a49e925;hpb=8383303e0acce6e4332e2a2097b832e2deb880ec;p=deliverable%2Fbinutils-gdb.git diff --git a/gold/merge.h b/gold/merge.h index a64932180e..47af24db07 100644 --- a/gold/merge.h +++ b/gold/merge.h @@ -1,6 +1,6 @@ // merge.h -- handle section merging for gold -*- C++ -*- -// Copyright 2006, 2007 Free Software Foundation, Inc. +// Copyright (C) 2006-2016 Free Software Foundation, Inc. // Written by Ian Lance Taylor . // This file is part of gold. @@ -24,6 +24,8 @@ #define GOLD_MERGE_H #include +#include +#include #include "stringpool.h" #include "output.h" @@ -31,34 +33,138 @@ namespace gold { -// This class manages mappings from input sections to offsets in an -// output section. This is used where input sections are merged. The -// actual data is stored in fields in Object. +// For each object with merge sections, we store an Object_merge_map. +// This is used to map locations in input sections to a merged output +// section. The output section itself is not recorded here--it can be +// found in the output_sections_ field of the Object. -class Merge_map +class Object_merge_map { public: - Merge_map() + Object_merge_map() + : section_merge_maps_() { } - // Add a mapping for the bytes from OFFSET to OFFSET + LENGTH in the - // input section SHNDX in object OBJECT to OUTPUT_OFFSET in the + ~Object_merge_map(); + + // Add a mapping for MERGE_MAP, for the bytes from OFFSET to OFFSET + // + LENGTH in the input section SHNDX to OUTPUT_OFFSET in the // output section. An OUTPUT_OFFSET of -1 means that the bytes are - // discarded. + // discarded. OUTPUT_OFFSET is relative to the start of the merged + // data in the output section. void - add_mapping(Relobj* object, unsigned int shndx, - section_offset_type offset, section_size_type length, - section_offset_type output_offset); - - // Return the output offset for an input address. The input address - // is at offset OFFSET in section SHNDX in OBJECT. This sets - // *OUTPUT_OFFSET to the offset in the output section; this will be - // -1 if the bytes are not being copied to the output. This returns - // true if the mapping is known, false otherwise. + add_mapping(const Output_section_data*, unsigned int shndx, + section_offset_type offset, section_size_type length, + section_offset_type output_offset); + + // Get the output offset for an input address. MERGE_MAP is the map + // we are looking for, or NULL if we don't care. The input address + // is at offset OFFSET in section SHNDX. This sets *OUTPUT_OFFSET + // to the offset in the output section; this will be -1 if the bytes + // are not being copied to the output. This returns true if the + // mapping is known, false otherwise. *OUTPUT_OFFSET is relative to + // the start of the merged data in the output section. bool - get_output_offset(const Relobj* object, unsigned int shndx, + get_output_offset(unsigned int shndx, section_offset_type offset, - section_offset_type *output_offset) const; + section_offset_type* output_offset); + + const Output_section_data* + find_merge_section(unsigned int shndx) const; + + // Initialize an mapping from input offsets to output addresses for + // section SHNDX. STARTING_ADDRESS is the output address of the + // merged section. + template + void + initialize_input_to_output_map( + unsigned int shndx, + typename elfcpp::Elf_types::Elf_Addr starting_address, + Unordered_map::Elf_Addr>*); + + // Map input section offsets to a length and an output section + // offset. An output section offset of -1 means that this part of + // the input section is being discarded. + struct Input_merge_entry + { + // The offset in the input section. + section_offset_type input_offset; + // The length. + section_size_type length; + // The offset in the output section. + section_offset_type output_offset; + }; + + // A list of entries for a particular input section. + struct Input_merge_map + { + void add_mapping(section_offset_type input_offset, section_size_type length, + section_offset_type output_offset); + + typedef std::vector Entries; + + // We store these with the Relobj, and we look them up by input + // section. It is possible to have two different merge maps + // associated with a single output section. For example, this + // happens routinely with .rodata, when merged string constants + // and merged fixed size constants are both put into .rodata. The + // output offset that we store is not the offset from the start of + // the output section; it is the offset from the start of the + // merged data in the output section. That means that the caller + // is going to add the offset of the merged data within the output + // section, which means that the caller needs to know which set of + // merged data it found the entry in. So it's not enough to find + // this data based on the input section and the output section; we + // also have to find it based on a set of merged data in the + // output section. In order to verify that we are looking at the + // right data, we store a pointer to the Merge_map here, and we + // pass in a pointer when looking at the data. If we are asked to + // look up information for a different Merge_map, we report that + // we don't have it, rather than trying a lookup and returning an + // answer which will receive the wrong offset. + const Output_section_data* output_data; + // The list of mappings. + Entries entries; + // Whether the ENTRIES field is sorted by input_offset. + bool sorted; + + Input_merge_map() + : output_data(NULL), entries(), sorted(true) + { } + }; + + // Get or make the Input_merge_map to use for the section SHNDX + // with MERGE_MAP. + Input_merge_map* + get_or_make_input_merge_map(const Output_section_data* merge_map, + unsigned int shndx); + + private: + // A less-than comparison routine for Input_merge_entry. + struct Input_merge_compare + { + bool + operator()(const Input_merge_entry& i1, const Input_merge_entry& i2) const + { return i1.input_offset < i2.input_offset; } + }; + + // Map input section indices to merge maps. + typedef std::vector > + Section_merge_maps; + + // Return a pointer to the Input_merge_map to use for the input + // section SHNDX, or NULL. + const Input_merge_map* + get_input_merge_map(unsigned int shndx) const; + + Input_merge_map * + get_input_merge_map(unsigned int shndx) { + return const_cast(static_cast( + this)->get_input_merge_map(shndx)); + } + + Section_merge_maps section_merge_maps_; }; // A general class for SHF_MERGE data, to hold functions shared by @@ -68,37 +174,102 @@ class Output_merge_base : public Output_section_data { public: Output_merge_base(uint64_t entsize, uint64_t addralign) - : Output_section_data(addralign), merge_map_(), entsize_(entsize) + : Output_section_data(addralign), entsize_(entsize), + keeps_input_sections_(false), first_relobj_(NULL), first_shndx_(-1), + input_sections_() { } - // Return the output offset for an input offset. - bool - do_output_offset(const Relobj* object, unsigned int shndx, - section_offset_type offset, - section_offset_type* poutput) const; - - protected: // Return the entry size. uint64_t entsize() const { return this->entsize_; } - // Add a mapping from an OFFSET in input section SHNDX in object - // OBJECT to an OUTPUT_OFFSET in the output section. + // Whether this is a merge string section. This is only true of + // Output_merge_string. + bool + is_string() + { return this->do_is_string(); } + + // Whether this keeps input sections. + bool + keeps_input_sections() const + { return this->keeps_input_sections_; } + + // Set the keeps-input-sections flag. This is virtual so that sub-classes + // can perform additional checks. void - add_mapping(Relobj* object, unsigned int shndx, section_offset_type offset, - section_size_type length, section_offset_type output_offset) + set_keeps_input_sections() + { this->do_set_keeps_input_sections(); } + + // Return the object of the first merged input section. This used + // for script processing. This is NULL if merge section is empty. + Relobj* + first_relobj() const + { return this->first_relobj_; } + + // Return the section index of the first merged input section. This + // is used for script processing. This is valid only if merge section + // is not valid. + unsigned int + first_shndx() const + { + gold_assert(this->first_relobj_ != NULL); + return this->first_shndx_; + } + + // Set of merged input sections. + typedef Unordered_set Input_sections; + + // Beginning of merged input sections. + Input_sections::const_iterator + input_sections_begin() const { - this->merge_map_.add_mapping(object, shndx, offset, length, output_offset); + gold_assert(this->keeps_input_sections_); + return this->input_sections_.begin(); } + // Beginning of merged input sections. + Input_sections::const_iterator + input_sections_end() const + { + gold_assert(this->keeps_input_sections_); + return this->input_sections_.end(); + } + + protected: + // Return the output offset for an input offset. + bool + do_output_offset(const Relobj* object, unsigned int shndx, + section_offset_type offset, + section_offset_type* poutput) const; + + // This may be overridden by the child class. + virtual bool + do_is_string() + { return false; } + + // This may be overridden by the child class. + virtual void + do_set_keeps_input_sections() + { this->keeps_input_sections_ = true; } + + // Record the merged input section for script processing. + void + record_input_section(Relobj* relobj, unsigned int shndx); + private: - // A mapping from input object/section/offset to offset in output - // section. - Merge_map merge_map_; // The entry size. For fixed-size constants, this is the size of // the constants. For strings, this is the size of a character. uint64_t entsize_; + // Whether we keep input sections. + bool keeps_input_sections_; + // Object of the first merged input section. We use this for script + // processing. + Relobj* first_relobj_; + // Section index of the first merged input section. + unsigned int first_shndx_; + // Input sections. We only keep them is keeps_input_sections_ is true. + Input_sections input_sections_; }; // Handle SHF_MERGE sections with fixed-size constant data. @@ -108,9 +279,11 @@ class Output_merge_data : public Output_merge_base public: Output_merge_data(uint64_t entsize, uint64_t addralign) : Output_merge_base(entsize, addralign), p_(NULL), len_(0), alc_(0), + input_count_(0), hashtable_(128, Merge_data_hash(this), Merge_data_eq(this)) { } + protected: // Add an input section. bool do_add_input_section(Relobj* object, unsigned int shndx); @@ -127,6 +300,23 @@ class Output_merge_data : public Output_merge_base void do_write_to_buffer(unsigned char*); + // Write to a map file. + void + do_print_to_mapfile(Mapfile* mapfile) const + { mapfile->print_output_data(this, _("** merge constants")); } + + // Print merge stats to stderr. + void + do_print_merge_stats(const char* section_name); + + // Set keeps-input-sections flag. + void + do_set_keeps_input_sections() + { + gold_assert(this->input_count_ == 0); + Output_merge_base::do_set_keeps_input_sections(); + } + private: // We build a hash table of the fixed-size constants. Each constant // is stored as a pointer into the section data we are accumulating. @@ -197,6 +387,8 @@ class Output_merge_data : public Output_merge_base section_size_type len_; // The size of the allocated buffer. section_size_type alc_; + // The number of entries seen in input files. + size_t input_count_; // The hash table. Merge_data_hashtable hashtable_; }; @@ -209,10 +401,9 @@ class Output_merge_string : public Output_merge_base { public: Output_merge_string(uint64_t addralign) - : Output_merge_base(sizeof(Char_type), addralign), stringpool_(), - merged_strings_() + : Output_merge_base(sizeof(Char_type), addralign), stringpool_(addralign), + merged_strings_lists_(), input_count_(0), input_size_(0) { - gold_assert(addralign <= sizeof(Char_type)); this->stringpool_.set_no_zero_null(); } @@ -238,6 +429,15 @@ class Output_merge_string : public Output_merge_base void do_write_to_buffer(unsigned char*); + // Write to a map file. + void + do_print_to_mapfile(Mapfile* mapfile) const + { mapfile->print_output_data(this, _("** merge strings")); } + + // Print merge stats to stderr. + void + do_print_merge_stats(const char* section_name); + // Writes the stringpool to a buffer. void stringpool_to_buffer(unsigned char* buffer, section_size_type buffer_size) @@ -248,37 +448,65 @@ class Output_merge_string : public Output_merge_base clear_stringpool() { this->stringpool_.clear(); } + // Whether this is a merge string section. + virtual bool + do_is_string() + { return true; } + + // Set keeps-input-sections flag. + void + do_set_keeps_input_sections() + { + gold_assert(this->input_count_ == 0); + Output_merge_base::do_set_keeps_input_sections(); + } + private: + // The name of the string type, for stats. + const char* + string_name(); + // As we see input sections, we build a mapping from object, section // index and offset to strings. struct Merged_string { - // The input object where the string was found. - Relobj* object; - // The input section in the input object. - unsigned int shndx; // The offset in the input section. section_offset_type offset; - // The string itself, a pointer into a Stringpool. - const Char_type* string; - // The length of the string in bytes, including the null terminator. - size_t length; - - Merged_string(Relobj *objecta, unsigned int shndxa, - section_offset_type offseta, const Char_type* stringa, - size_t lengtha) - : object(objecta), shndx(shndxa), offset(offseta), string(stringa), - length(lengtha) + // The key in the Stringpool. + Stringpool::Key stringpool_key; + + Merged_string(section_offset_type offseta, Stringpool::Key stringpool_keya) + : offset(offseta), stringpool_key(stringpool_keya) { } }; typedef std::vector Merged_strings; + struct Merged_strings_list + { + // The input object where the strings were found. + Relobj* object; + // The input section in the input object. + unsigned int shndx; + // The list of merged strings. + Merged_strings merged_strings; + + Merged_strings_list(Relobj* objecta, unsigned int shndxa) + : object(objecta), shndx(shndxa), merged_strings() + { } + }; + + typedef std::vector Merged_strings_lists; + // As we see the strings, we add them to a Stringpool. Stringpool_template stringpool_; // Map from a location in an input object to an entry in the // Stringpool. - Merged_strings merged_strings_; + Merged_strings_lists merged_strings_lists_; + // The number of entries seen in input files. + size_t input_count_; + // The total size of input sections. + size_t input_size_; }; } // End namespace gold.