diff options
Diffstat (limited to 'gold/object.h')
| -rw-r--r-- | gold/object.h | 180 |
1 files changed, 142 insertions, 38 deletions
diff --git a/gold/object.h b/gold/object.h index 1ad9796..f5e4ab6 100644 --- a/gold/object.h +++ b/gold/object.h @@ -622,6 +622,71 @@ Relobj::output_section(unsigned int shndx, section_offset_type* poff) const return mo.output_section; } +// This class is used to handle relocations against a section symbol +// in an SHF_MERGE section. For such a symbol, we need to know the +// addend of the relocation before we can determine the final value. +// The addend gives us the location in the input section, and we can +// determine how it is mapped to the output section. For a +// non-section symbol, we apply the addend to the final value of the +// symbol; that is done in finalize_local_symbols, and does not use +// this class. + +template<int size> +class Merged_symbol_value +{ + public: + typedef typename elfcpp::Elf_types<size>::Elf_Addr Value; + + // We use a hash table to map offsets in the input section to output + // addresses. + typedef Unordered_map<section_offset_type, Value> Output_addresses; + + Merged_symbol_value(Value input_value, Value output_start_address) + : input_value_(input_value), output_start_address_(output_start_address), + output_addresses_() + { } + + // Initialize the hash table. + void + initialize_input_to_output_map(const Relobj*, unsigned int input_shndx); + + // Release the hash table to save space. + void + free_input_to_output_map() + { this->output_addresses_.clear(); } + + // Get the output value corresponding to an addend. The object and + // input section index are passed in because the caller will have + // them; otherwise we could store them here. + Value + value(const Relobj* object, unsigned int input_shndx, Value addend) const + { + Value input_offset = this->input_value_ + addend; + typename Output_addresses::const_iterator p = + this->output_addresses_.find(input_offset); + if (p != this->output_addresses_.end()) + return p->second; + + return this->value_from_output_section(object, input_shndx, input_offset); + } + + private: + // Get the output value for an input offset if we couldn't find it + // in the hash table. + Value + value_from_output_section(const Relobj*, unsigned int input_shndx, + Value input_offset) const; + + // The value of the section symbol in the input file. This is + // normally zero, but could in principle be something else. + Value input_value_; + // The start address of this merged section in the output file. + Value output_start_address_; + // A hash table which maps offsets in the input section to output + // addresses. This only maps specific offsets, not all offsets. + Output_addresses output_addresses_; +}; + // This POD class is holds the value of a symbol. This is used for // local symbols, and for all symbols during relocation processing. // For special sections, such as SHF_MERGE sections, this calls a @@ -636,8 +701,8 @@ class Symbol_value Symbol_value() : output_symtab_index_(0), output_dynsym_index_(-1U), input_shndx_(0), is_section_symbol_(false), is_tls_symbol_(false), - needs_output_address_(false), value_(0) - { } + has_output_value_(true) + { this->u_.value = 0; } // Get the value of this symbol. OBJECT is the object in which this // symbol is defined, and ADDEND is an addend to add to the value. @@ -645,41 +710,64 @@ class Symbol_value Value value(const Sized_relobj<size, big_endian>* object, Value addend) const { - if (!this->needs_output_address_) - return this->value_ + addend; - return object->local_value(this->input_shndx_, this->value_, - this->is_section_symbol_, addend); + if (this->has_output_value_) + return this->u_.value + addend; + else + return this->u_.merged_symbol_value->value(object, this->input_shndx_, + addend); } // Set the value of this symbol in the output symbol table. void set_output_value(Value value) + { this->u_.value = value; } + + // For a section symbol in a merged section, we need more + // information. + void + set_merged_symbol_value(Merged_symbol_value<size>* msv) { - this->value_ = value; - this->needs_output_address_ = false; + gold_assert(this->is_section_symbol_); + this->has_output_value_ = false; + this->u_.merged_symbol_value = msv; } - // Set the value of the symbol from the input file. This value - // will usually be replaced during finalization with the output - // value, but if the symbol is mapped to an output section which - // requires special handling to determine the output value, we - // leave the input value in place until later. This is used for - // SHF_MERGE sections. + // Initialize the input to output map for a section symbol in a + // merged section. We also initialize the value of a non-section + // symbol in a merged section. void - set_input_value(Value value) + initialize_input_to_output_map(const Relobj* object) { - this->value_ = value; - this->needs_output_address_ = true; + if (!this->has_output_value_) + { + gold_assert(this->is_section_symbol_); + Merged_symbol_value<size>* msv = this->u_.merged_symbol_value; + msv->initialize_input_to_output_map(object, this->input_shndx_); + } } - // Return the input value. - Value - input_value() const + // Free the input to output map for a section symbol in a merged + // section. + void + free_input_to_output_map() { - gold_assert(this->needs_output_address_); - return this->value_; + if (!this->has_output_value_) + this->u_.merged_symbol_value->free_input_to_output_map(); } + // Set the value of the symbol from the input file. This is only + // called by count_local_symbols, to communicate the value to + // finalize_local_symbols. + void + set_input_value(Value value) + { this->u_.value = value; } + + // Return the input value. This is only called by + // finalize_local_symbols. + Value + input_value() const + { return this->u_.value; } + // Return whether this symbol should go into the output symbol // table. bool @@ -757,6 +845,11 @@ class Symbol_value input_shndx() const { return this->input_shndx_; } + // Whether this is a section symbol. + bool + is_section_symbol() const + { return this->is_section_symbol_; } + // Record that this is a section symbol. void set_is_section_symbol() @@ -786,14 +879,23 @@ class Symbol_value bool is_section_symbol_ : 1; // Whether this is a STT_TLS symbol. bool is_tls_symbol_ : 1; - // Whether getting the value of this symbol requires calling an - // Output_section method. For example, this will be true of a - // symbol in a SHF_MERGE section. - bool needs_output_address_ : 1; - // The value of the symbol. If !needs_output_address_, this is the - // value in the output file. If needs_output_address_, this is the - // value in the input file. - Value value_; + // Whether this symbol has a value for the output file. This is + // normally set to true during Layout::finalize, by + // finalize_local_symbols. It will be false for a section symbol in + // a merge section, as for such symbols we can not determine the + // value to use in a relocation until we see the addend. + bool has_output_value_ : 1; + union + { + // This is used if has_output_value_ is true. Between + // count_local_symbols and finalize_local_symbols, this is the + // value in the input file. After finalize_local_symbols, it is + // the value in the output file. + Value value; + // This is used if has_output_value_ is false. It points to the + // information we need to get the value for a merge section. + Merged_symbol_value<size>* merged_symbol_value; + } u_; }; // A regular object file. This is size and endian specific. @@ -876,14 +978,6 @@ class Sized_relobj : public Relobj Address local_symbol_value(unsigned int symndx) const; - // Return the value of a local symbol defined in input section - // SHNDX, with value VALUE, adding addend ADDEND. IS_SECTION_SYMBOL - // indicates whether the symbol is a section symbol. This handles - // SHF_MERGE sections. - Address - local_value(unsigned int shndx, Address value, bool is_section_symbol, - Address addend) const; - void set_needs_output_dynsym_entry(unsigned int sym) { @@ -1119,6 +1213,16 @@ class Sized_relobj : public Relobj relocate_sections(const General_options& options, const Symbol_table*, const Layout*, const unsigned char* pshdrs, Views*); + // Initialize input to output maps for section symbols in merged + // sections. + void + initialize_input_to_output_maps(); + + // Free the input to output maps for section symbols in merged + // sections. + void + free_input_to_output_maps(); + // Write out the local symbols. void write_local_symbols(Output_file*, |