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Diffstat (limited to 'gold/arm.cc')
| -rw-r--r-- | gold/arm.cc | 672 |
1 files changed, 672 insertions, 0 deletions
diff --git a/gold/arm.cc b/gold/arm.cc new file mode 100644 index 0000000..580b3ef --- /dev/null +++ b/gold/arm.cc @@ -0,0 +1,672 @@ +// arm.cc -- arm target support for gold. + +// Copyright 2009 Free Software Foundation, Inc. +// Written by Doug Kwan <dougkwan@google.com> based on the i386 code +// 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. + +#include "gold.h" + +#include <cstring> +#include <limits> +#include <cstdio> +#include <string> + +#include "elfcpp.h" +#include "parameters.h" +#include "reloc.h" +#include "arm.h" +#include "object.h" +#include "symtab.h" +#include "layout.h" +#include "output.h" +#include "copy-relocs.h" +#include "target.h" +#include "target-reloc.h" +#include "target-select.h" +#include "tls.h" +#include "defstd.h" + +namespace +{ + +using namespace gold; + +// The arm target class. +// +// This is a very simple port of gold for ARM-EABI. It is intended for +// supporting Android only for the time being. Only these relocation types +// are supported. +// +// R_ARM_NONE +// R_ARM_ABS32 +// R_ARM_REL32 +// R_ARM_THM_CALL +// R_ARM_COPY +// R_ARM_GLOB_DAT +// R_ARM_BASE_PREL +// R_ARM_JUMP_SLOT +// R_ARM_RELATIVE +// R_ARM_GOTOFF32 +// R_ARM_GOT_BREL +// R_ARM_PLT32 +// R_ARM_CALL +// R_ARM_JUMP24 +// R_ARM_TARGET1 +// R_ARM_PREL31 +// +// Coming soon (pending patches): +// - Support for dynamic symbols (GOT, PLT and etc). +// - Local scanner +// - Global scanner +// - Relocation +// - Defining section symbols __exidx_start and __exidx_stop. +// - Support interworking. +// - Mergeing all .ARM.xxx.yyy sections into .ARM.xxx. Currently, they +// are incorrectly merged into an .ARM section. +// +// TODOs: +// - Create a PT_ARM_EXIDX program header for a shared object that +// might throw an exception. +// - Support more relocation types as needed. + +template<bool big_endian> +class Target_arm : public Sized_target<32, big_endian> +{ + public: + typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, big_endian> + Reloc_section; + + Target_arm() + : Sized_target<32, big_endian>(&arm_info) + { } + + // Process the relocations to determine unreferenced sections for + // garbage collection. + void + gc_process_relocs(const General_options& options, + Symbol_table* symtab, + Layout* layout, + Sized_relobj<32, 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); + + // Scan the relocations to look for symbol adjustments. + void + scan_relocs(const General_options& options, + Symbol_table* symtab, + Layout* layout, + Sized_relobj<32, 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); + + // Finalize the sections. + void + do_finalize_sections(Layout*); + + // Return the value to use for a dynamic which requires special + // treatment. + uint64_t + do_dynsym_value(const Symbol*) const; + + // Relocate a section. + void + relocate_section(const Relocate_info<32, 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, + elfcpp::Elf_types<32>::Elf_Addr view_address, + section_size_type view_size); + + // Scan the relocs during a relocatable link. + void + scan_relocatable_relocs(const General_options& options, + Symbol_table* symtab, + Layout* layout, + Sized_relobj<32, 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*); + + // Relocate a section during a relocatable link. + void + relocate_for_relocatable(const Relocate_info<32, 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, + elfcpp::Elf_types<32>::Elf_Addr view_address, + section_size_type view_size, + unsigned char* reloc_view, + section_size_type reloc_view_size); + + // Return whether SYM is defined by the ABI. + bool + do_is_defined_by_abi(Symbol* sym) const + { return strcmp(sym->name(), "__tls_get_addr") == 0; } + + // Map platform-specific reloc types + static unsigned int + get_real_reloc_type (unsigned int r_type); + + private: + // The class which scans relocations. + class Scan + { + public: + Scan() + { } + + inline void + local(const General_options& options, Symbol_table* symtab, + Layout* layout, Target_arm* target, + Sized_relobj<32, big_endian>* object, + unsigned int data_shndx, + Output_section* output_section, + const elfcpp::Rel<32, big_endian>& reloc, unsigned int r_type, + const elfcpp::Sym<32, big_endian>& lsym); + + inline void + global(const General_options& options, Symbol_table* symtab, + Layout* layout, Target_arm* target, + Sized_relobj<32, big_endian>* object, + unsigned int data_shndx, + Output_section* output_section, + const elfcpp::Rel<32, big_endian>& reloc, unsigned int r_type, + Symbol* gsym); + + private: + static void + unsupported_reloc_local(Sized_relobj<32, big_endian>*, + unsigned int r_type); + + static void + unsupported_reloc_global(Sized_relobj<32, big_endian>*, + unsigned int r_type, Symbol*); + }; + + // The class which implements relocation. + class Relocate + { + public: + Relocate() + { } + + ~Relocate() + { } + + // Do a relocation. Return false if the caller should not issue + // any warnings about this relocation. + inline bool + relocate(const Relocate_info<32, big_endian>*, Target_arm*, + Output_section*, size_t relnum, + const elfcpp::Rel<32, big_endian>&, + unsigned int r_type, const Sized_symbol<32>*, + const Symbol_value<32>*, + unsigned char*, elfcpp::Elf_types<32>::Elf_Addr, + section_size_type); + }; + + // A class which returns the size required for a relocation type, + // used while scanning relocs during a relocatable link. + class Relocatable_size_for_reloc + { + public: + unsigned int + get_size_for_reloc(unsigned int, Relobj*); + }; + + // Information about this specific target which we pass to the + // general Target structure. + static const Target::Target_info arm_info; +}; + +template<bool big_endian> +const Target::Target_info Target_arm<big_endian>::arm_info = +{ + 32, // size + big_endian, // is_big_endian + elfcpp::EM_ARM, // machine_code + false, // has_make_symbol + false, // has_resolve + false, // has_code_fill + true, // is_default_stack_executable + '\0', // wrap_char + "/usr/lib/libc.so.1", // dynamic_linker + 0x8000, // default_text_segment_address + 0x1000, // abi_pagesize (overridable by -z max-page-size) + 0x1000 // common_pagesize (overridable by -z common-page-size) +}; + +// Report an unsupported relocation against a local symbol. + +template<bool big_endian> +void +Target_arm<big_endian>::Scan::unsupported_reloc_local( + Sized_relobj<32, big_endian>* object, + unsigned int r_type) +{ + gold_error(_("%s: unsupported reloc %u against local symbol"), + object->name().c_str(), r_type); +} + +// Scan a relocation for a local symbol. + +template<bool big_endian> +inline void +Target_arm<big_endian>::Scan::local(const General_options&, + Symbol_table* /* symtab */, + Layout* /* layout */, + Target_arm* /* target */, + Sized_relobj<32, big_endian>* object, + unsigned int /* data_shndx */, + Output_section* /* output_section */, + const elfcpp::Rel<32, big_endian>& /* reloc */, + unsigned int r_type, + const elfcpp::Sym<32, big_endian>&) +{ + r_type = get_real_reloc_type(r_type); + switch (r_type) + { + case elfcpp::R_ARM_NONE: + break; + + default: + unsupported_reloc_local(object, r_type); + break; + } +} + +// Report an unsupported relocation against a global symbol. + +template<bool big_endian> +void +Target_arm<big_endian>::Scan::unsupported_reloc_global( + Sized_relobj<32, big_endian>* object, + unsigned int r_type, + Symbol* gsym) +{ + gold_error(_("%s: unsupported reloc %u against global symbol %s"), + object->name().c_str(), r_type, gsym->demangled_name().c_str()); +} + +// Scan a relocation for a global symbol. + +template<bool big_endian> +inline void +Target_arm<big_endian>::Scan::global(const General_options&, + Symbol_table* /* symtab */, + Layout* /* layout */, + Target_arm* /* target */, + Sized_relobj<32, big_endian>* object, + unsigned int /* data_shndx */, + Output_section* /* output_section */, + const elfcpp::Rel<32, big_endian>& /* reloc */, + unsigned int r_type, + Symbol* gsym) +{ + r_type = get_real_reloc_type(r_type); + switch (r_type) + { + case elfcpp::R_ARM_NONE: + break; + + default: + unsupported_reloc_global(object, r_type, gsym); + break; + } +} + +// Process relocations for gc. + +template<bool big_endian> +void +Target_arm<big_endian>::gc_process_relocs(const General_options& options, + Symbol_table* symtab, + Layout* layout, + Sized_relobj<32, big_endian>* object, + unsigned int data_shndx, + unsigned int, + 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) +{ + typedef Target_arm<big_endian> Arm; + typedef typename Target_arm<big_endian>::Scan Scan; + + gold::gc_process_relocs<32, big_endian, Arm, elfcpp::SHT_REL, Scan>( + options, + symtab, + layout, + this, + object, + data_shndx, + prelocs, + reloc_count, + output_section, + needs_special_offset_handling, + local_symbol_count, + plocal_symbols); +} + +// Scan relocations for a section. + +template<bool big_endian> +void +Target_arm<big_endian>::scan_relocs(const General_options& options, + Symbol_table* symtab, + Layout* layout, + Sized_relobj<32, 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) +{ + typedef typename Target_arm<big_endian>::Scan Scan; + if (sh_type == elfcpp::SHT_RELA) + { + gold_error(_("%s: unsupported RELA reloc section"), + object->name().c_str()); + return; + } + + gold::scan_relocs<32, big_endian, Target_arm, elfcpp::SHT_REL, Scan>( + options, + symtab, + layout, + this, + object, + data_shndx, + prelocs, + reloc_count, + output_section, + needs_special_offset_handling, + local_symbol_count, + plocal_symbols); +} + +// Finalize the sections. + +template<bool big_endian> +void +Target_arm<big_endian>::do_finalize_sections(Layout* /* layout */) +{ + gold_unreachable (); +} + +// Perform a relocation. + +template<bool big_endian> +inline bool +Target_arm<big_endian>::Relocate::relocate( + const Relocate_info<32, big_endian>* /* relinfo */, + Target_arm* /* target */, + Output_section* /* output_section */, + size_t /* relnum */, + const elfcpp::Rel<32, big_endian>& /* rel */, + unsigned int r_type, + const Sized_symbol<32>* /* gsym */, + const Symbol_value<32>* /* psymval */, + unsigned char* /* view */, + elfcpp::Elf_types<32>::Elf_Addr /* address */, + section_size_type /* view_size */ ) +{ + switch (r_type) + { + case elfcpp::R_ARM_NONE: + break; + + default: + gold_unreachable(); + } + + return true; +} + +// Relocate section data. + +template<bool big_endian> +void +Target_arm<big_endian>::relocate_section( + const Relocate_info<32, big_endian>* relinfo, + unsigned int sh_type, + const unsigned char* prelocs, + size_t reloc_count, + Output_section* output_section, + bool needs_special_offset_handling, + unsigned char* view, + elfcpp::Elf_types<32>::Elf_Addr address, + section_size_type view_size) +{ + typedef typename Target_arm<big_endian>::Relocate Arm_relocate; + gold_assert(sh_type == elfcpp::SHT_REL); + + gold::relocate_section<32, big_endian, Target_arm, elfcpp::SHT_REL, + Arm_relocate>( + relinfo, + this, + prelocs, + reloc_count, + output_section, + needs_special_offset_handling, + view, + address, + view_size); +} + +// Return the size of a relocation while scanning during a relocatable +// link. + +template<bool big_endian> +unsigned int +Target_arm<big_endian>::Relocatable_size_for_reloc::get_size_for_reloc( + unsigned int r_type, + Relobj* object) +{ + r_type = get_real_reloc_type(r_type); + switch (r_type) + { + case elfcpp::R_ARM_NONE: + return 0; + + case elfcpp::R_ARM_ABS32: + case elfcpp::R_ARM_REL32: + case elfcpp::R_ARM_THM_CALL: + case elfcpp::R_ARM_GOTOFF32: + case elfcpp::R_ARM_BASE_PREL: + case elfcpp::R_ARM_GOT_BREL: + case elfcpp::R_ARM_PLT32: + case elfcpp::R_ARM_CALL: + case elfcpp::R_ARM_JUMP24: + case elfcpp::R_ARM_PREL31: + return 4; + + case elfcpp::R_ARM_TARGET1: + // This should have been mapped to another type already. + // Fall through. + case elfcpp::R_ARM_COPY: + case elfcpp::R_ARM_GLOB_DAT: + case elfcpp::R_ARM_JUMP_SLOT: + case elfcpp::R_ARM_RELATIVE: + // These are relocations which should only be seen by the + // dynamic linker, and should never be seen here. + gold_error(_("%s: unexpected reloc %u in object file"), + object->name().c_str(), r_type); + return 0; + + default: + object->error(_("unsupported reloc %u in object file"), r_type); + return 0; + } +} + +// Scan the relocs during a relocatable link. + +template<bool big_endian> +void +Target_arm<big_endian>::scan_relocatable_relocs( + const General_options& options, + Symbol_table* symtab, + Layout* layout, + Sized_relobj<32, 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* rr) +{ + gold_assert(sh_type == elfcpp::SHT_REL); + + typedef gold::Default_scan_relocatable_relocs<elfcpp::SHT_REL, + Relocatable_size_for_reloc> Scan_relocatable_relocs; + + gold::scan_relocatable_relocs<32, big_endian, elfcpp::SHT_REL, + Scan_relocatable_relocs>( + options, + symtab, + layout, + object, + data_shndx, + prelocs, + reloc_count, + output_section, + needs_special_offset_handling, + local_symbol_count, + plocal_symbols, + rr); +} + +// Relocate a section during a relocatable link. + +template<bool big_endian> +void +Target_arm<big_endian>::relocate_for_relocatable( + const Relocate_info<32, big_endian>* relinfo, + 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* rr, + unsigned char* view, + elfcpp::Elf_types<32>::Elf_Addr view_address, + section_size_type view_size, + unsigned char* reloc_view, + section_size_type reloc_view_size) +{ + gold_assert(sh_type == elfcpp::SHT_REL); + + gold::relocate_for_relocatable<32, big_endian, elfcpp::SHT_REL>( + relinfo, + prelocs, + reloc_count, + output_section, + offset_in_output_section, + rr, + view, + view_address, + view_size, + reloc_view, + reloc_view_size); +} + +template<bool big_endian> +uint64_t +Target_arm<big_endian>::do_dynsym_value(const Symbol* /*gsym*/) const +{ + gold_unreachable (); + return 0; +} + +// Map platform-specific relocs to real relocs +// +template<bool big_endian> +unsigned int +Target_arm<big_endian>::get_real_reloc_type (unsigned int r_type) +{ + switch (r_type) + { + case elfcpp::R_ARM_TARGET1: + // This is either R_ARM_ABS32 or R_ARM_REL32; + return elfcpp::R_ARM_ABS32; + + case elfcpp::R_ARM_TARGET2: + // This can be any reloc type but ususally is R_ARM_GOT_PREL + return elfcpp::R_ARM_GOT_PREL; + + default: + return r_type; + } +} + +// The selector for arm object files. + +template<bool big_endian> +class Target_selector_arm : public Target_selector +{ + public: + Target_selector_arm() + : Target_selector(elfcpp::EM_ARM, 32, big_endian, + (big_endian ? "elf32-bigarm" : "elf32-littlearm")) + { } + + Target* + do_instantiate_target() + { return new Target_arm<big_endian>(); } +}; + +Target_selector_arm<false> target_selector_arm; +Target_selector_arm<true> target_selector_armbe; + +} // End anonymous namespace. |