// target.h -- target support for gold -*- C++ -*-
+// Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
+// Written by Ian Lance Taylor <iant@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.
+
// The abstract class Target is the interface for target specific
// support. It defines abstract methods which each target must
// implement. Typically there will be one target per processor, but
#ifndef GOLD_TARGET_H
#define GOLD_TARGET_H
-#include <cassert>
-
#include "elfcpp.h"
+#include "options.h"
+#include "parameters.h"
namespace gold
{
class Object;
template<int size, bool big_endian>
class Sized_relobj;
+class Relocatable_relocs;
template<int size, bool big_endian>
-struct Relocate_info;
+class Relocate_info;
class Symbol;
template<int size>
class Sized_symbol;
class Symbol_table;
+class Output_section;
// The abstract class for target specific handling.
has_resolve() const
{ return this->pti_->has_resolve; }
+ // Whether this target has a specific code fill function.
+ bool
+ has_code_fill() const
+ { return this->pti_->has_code_fill; }
+
// Return the default name of the dynamic linker.
const char*
dynamic_linker() const
// Return the default address to use for the text segment.
uint64_t
- text_segment_address() const
- { return this->pti_->text_segment_address; }
+ default_text_segment_address() const
+ { return this->pti_->default_text_segment_address; }
// Return the ABI specified page size.
uint64_t
abi_pagesize() const
- { return this->pti_->abi_pagesize; }
+ {
+ if (parameters->options().max_page_size() > 0)
+ return parameters->options().max_page_size();
+ else
+ return this->pti_->abi_pagesize;
+ }
// Return the common page size used on actual systems.
uint64_t
common_pagesize() const
- { return this->pti_->common_pagesize; }
+ {
+ if (parameters->options().common_page_size() > 0)
+ return std::min(parameters->options().common_page_size(),
+ this->abi_pagesize());
+ else
+ return std::min(this->pti_->common_pagesize,
+ this->abi_pagesize());
+ }
+
+ // If we see some object files with .note.GNU-stack sections, and
+ // some objects files without them, this returns whether we should
+ // consider the object files without them to imply that the stack
+ // should be executable.
+ bool
+ is_default_stack_executable() const
+ { return this->pti_->is_default_stack_executable; }
+
+ // Return a character which may appear as a prefix for a wrap
+ // symbol. If this character appears, we strip it when checking for
+ // wrapping and add it back when forming the final symbol name.
+ // This should be '\0' if not special prefix is required, which is
+ // the normal case.
+ char
+ wrap_char() const
+ { return this->pti_->wrap_char; }
+
+ // This is called to tell the target to complete any sections it is
+ // handling. After this all sections must have their final size.
+ void
+ finalize_sections(Layout* layout)
+ { return this->do_finalize_sections(layout); }
+
+ // Return the value to use for a global symbol which needs a special
+ // value in the dynamic symbol table. This will only be called if
+ // the backend first calls symbol->set_needs_dynsym_value().
+ uint64_t
+ dynsym_value(const Symbol* sym) const
+ { return this->do_dynsym_value(sym); }
+
+ // Return a string to use to fill out a code section. This is
+ // basically one or more NOPS which must fill out the specified
+ // length in bytes.
+ std::string
+ code_fill(section_size_type length) const
+ { return this->do_code_fill(length); }
+
+ // Return whether SYM is known to be defined by the ABI. This is
+ // used to avoid inappropriate warnings about undefined symbols.
+ bool
+ is_defined_by_abi(const Symbol* sym) const
+ { return this->do_is_defined_by_abi(sym); }
+
+ // Adjust the output file header before it is written out. VIEW
+ // points to the header in external form. LEN is the length.
+ void
+ adjust_elf_header(unsigned char* view, int len) const
+ { return this->do_adjust_elf_header(view, len); }
protected:
// This struct holds the constant information for a child class. We
bool has_make_symbol;
// Whether this target has a specific resolve function.
bool has_resolve;
+ // Whether this target has a specific code fill function.
+ bool has_code_fill;
+ // Whether an object file with no .note.GNU-stack sections implies
+ // that the stack should be executable.
+ bool is_default_stack_executable;
+ // Prefix character to strip when checking for wrapping.
+ char wrap_char;
// The default dynamic linker name.
const char* dynamic_linker;
// The default text segment address.
- uint64_t text_segment_address;
+ uint64_t default_text_segment_address;
// The ABI specified page size.
uint64_t abi_pagesize;
// The common page size used by actual implementations.
: pti_(pti)
{ }
+ // Virtual function which may be implemented by the child class.
+ virtual void
+ do_finalize_sections(Layout*)
+ { }
+
+ // Virtual function which may be implemented by the child class.
+ virtual uint64_t
+ do_dynsym_value(const Symbol*) const
+ { gold_unreachable(); }
+
+ // Virtual function which must be implemented by the child class if
+ // needed.
+ virtual std::string
+ do_code_fill(section_size_type) const
+ { gold_unreachable(); }
+
+ // Virtual function which may be implemented by the child class.
+ virtual bool
+ do_is_defined_by_abi(const Symbol*) const
+ { return false; }
+
+ // Adjust the output file header before it is written out. VIEW
+ // points to the header in external form. LEN is the length, and
+ // will be one of the values of elfcpp::Elf_sizes<size>::ehdr_size.
+ // By default, we do nothing.
+ virtual void
+ do_adjust_elf_header(unsigned char*, int) const
+ { }
+
private:
Target(const Target&);
Target& operator=(const Target&);
// symbol table. This will only be called if has_make_symbol()
// returns true.
virtual Sized_symbol<size>*
- make_symbol()
- { abort(); }
+ make_symbol() const
+ { gold_unreachable(); }
// Resolve a symbol for the target. This should be overridden by a
// target which needs to take special action. TO is the
// pre-existing symbol. SYM is the new symbol, seen in OBJECT.
- // This will only be called if has_resolve() returns true.
+ // VERSION is the version of SYM. This will only be called if
+ // has_resolve() returns true.
+ virtual void
+ resolve(Symbol*, const elfcpp::Sym<size, big_endian>&, Object*,
+ const char*)
+ { gold_unreachable(); }
+
+ // Process the relocs for a section, and record information of the
+ // mapping from source to destination sections. This mapping is later
+ // used to determine unreferenced garbage sections. This procedure is
+ // only called during garbage collection.
virtual void
- resolve(Symbol*, const elfcpp::Sym<size, big_endian>&, Object*)
- { abort(); }
+ gc_process_relocs(const General_options& options,
+ Symbol_table* symtab,
+ Layout* layout,
+ Sized_relobj<size, big_endian>* object,
+ unsigned int data_shndx,
+ unsigned int sh_type,
+ const unsigned char* prelocs,
+ size_t reloc_count,
+ Output_section* output_section,
+ bool needs_special_offset_handling,
+ size_t local_symbol_count,
+ const unsigned char* plocal_symbols) = 0;
// Scan the relocs for a section, and record any information
// required for the symbol. OPTIONS is the command line options.
// SYMTAB is the symbol table. OBJECT is the object in which the
- // section appears. SH_TYPE is the type of the relocation section,
+ // section appears. DATA_SHNDX is the section index that these
+ // relocs apply to. SH_TYPE is the type of the relocation section,
// SHT_REL or SHT_RELA. PRELOCS points to the relocation data.
// RELOC_COUNT is the number of relocs. LOCAL_SYMBOL_COUNT is the
- // number of local symbols. PLOCAL_SYMBOLS points to the local
- // symbol data from OBJECT. GLOBAL_SYMBOLS is the array of pointers
- // to the global symbol table from OBJECT.
+ // number of local symbols. OUTPUT_SECTION is the output section.
+ // NEEDS_SPECIAL_OFFSET_HANDLING is true if offsets to the output
+ // sections are not mapped as usual. PLOCAL_SYMBOLS points to the
+ // local symbol data from OBJECT. GLOBAL_SYMBOLS is the array of
+ // pointers to the global symbol table from OBJECT.
virtual void
scan_relocs(const General_options& options,
Symbol_table* symtab,
Layout* layout,
Sized_relobj<size, big_endian>* object,
+ unsigned int data_shndx,
unsigned int sh_type,
const unsigned char* prelocs,
size_t reloc_count,
+ Output_section* output_section,
+ bool needs_special_offset_handling,
size_t local_symbol_count,
- const unsigned char* plocal_symbols,
- Symbol** global_symbols) = 0;
+ const unsigned char* plocal_symbols) = 0;
// Relocate section data. SH_TYPE is the type of the relocation
// section, SHT_REL or SHT_RELA. PRELOCS points to the relocation
- // information. RELOC_COUNT is the number of relocs. VIEW is a
- // view into the output file holding the section contents,
- // VIEW_ADDRESS is the virtual address of the view, and VIEW_SIZE is
- // the size of the view.
+ // information. RELOC_COUNT is the number of relocs.
+ // OUTPUT_SECTION is the output section.
+ // NEEDS_SPECIAL_OFFSET_HANDLING is true if offsets must be mapped
+ // to correspond to the output section. VIEW is a view into the
+ // output file holding the section contents, VIEW_ADDRESS is the
+ // virtual address of the view, and VIEW_SIZE is the size of the
+ // view. If NEEDS_SPECIAL_OFFSET_HANDLING is true, the VIEW_xx
+ // parameters refer to the complete output section data, not just
+ // the input section data.
virtual void
relocate_section(const Relocate_info<size, big_endian>*,
unsigned int sh_type,
const unsigned char* prelocs,
size_t reloc_count,
+ Output_section* output_section,
+ bool needs_special_offset_handling,
unsigned char* view,
typename elfcpp::Elf_types<size>::Elf_Addr view_address,
- off_t view_size) = 0;
+ section_size_type view_size) = 0;
+
+ // Scan the relocs during a relocatable link. The parameters are
+ // like scan_relocs, with an additional Relocatable_relocs
+ // parameter, used to record the disposition of the relocs.
+ virtual void
+ scan_relocatable_relocs(const General_options& options,
+ Symbol_table* symtab,
+ Layout* layout,
+ Sized_relobj<size, big_endian>* object,
+ unsigned int data_shndx,
+ unsigned int sh_type,
+ const unsigned char* prelocs,
+ size_t reloc_count,
+ Output_section* output_section,
+ bool needs_special_offset_handling,
+ size_t local_symbol_count,
+ const unsigned char* plocal_symbols,
+ Relocatable_relocs*) = 0;
+
+ // Relocate a section during a relocatable link. The parameters are
+ // like relocate_section, with additional parameters for the view of
+ // the output reloc section.
+ virtual void
+ relocate_for_relocatable(const Relocate_info<size, big_endian>*,
+ unsigned int sh_type,
+ const unsigned char* prelocs,
+ size_t reloc_count,
+ Output_section* output_section,
+ off_t offset_in_output_section,
+ const Relocatable_relocs*,
+ unsigned char* view,
+ typename elfcpp::Elf_types<size>::Elf_Addr
+ view_address,
+ section_size_type view_size,
+ unsigned char* reloc_view,
+ section_size_type reloc_view_size) = 0;
protected:
Sized_target(const Target::Target_info* pti)
: Target(pti)
{
- assert(pti->size == size);
- assert(pti->is_big_endian ? big_endian : !big_endian);
+ gold_assert(pti->size == size);
+ gold_assert(pti->is_big_endian ? big_endian : !big_endian);
}
};
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