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550 lines
14 KiB
C++
550 lines
14 KiB
C++
// reloc.cc -- relocate input files for gold.
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#include "gold.h"
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#include "workqueue.h"
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#include "object.h"
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#include "output.h"
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#include "reloc.h"
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namespace gold
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{
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// Read_relocs methods.
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// These tasks just read the relocation information from the file.
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// After reading it, the start another task to process the
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// information. These tasks requires access to the file.
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Task::Is_runnable_type
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Read_relocs::is_runnable(Workqueue*)
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{
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return this->object_->is_locked() ? IS_LOCKED : IS_RUNNABLE;
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}
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// Lock the file.
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Task_locker*
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Read_relocs::locks(Workqueue*)
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{
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return new Task_locker_obj<Object>(*this->object_);
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}
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// Read the relocations and then start a Scan_relocs_task.
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void
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Read_relocs::run(Workqueue* workqueue)
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{
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Read_relocs_data *rd = new Read_relocs_data;
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this->object_->read_relocs(rd);
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workqueue->queue_front(new Scan_relocs(this->options_, this->symtab_,
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this->layout_, this->object_, rd,
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this->symtab_lock_, this->blocker_));
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}
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// Scan_relocs methods.
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// These tasks scan the relocations read by Read_relocs and mark up
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// the symbol table to indicate which relocations are required. We
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// use a lock on the symbol table to keep them from interfering with
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// each other.
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Task::Is_runnable_type
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Scan_relocs::is_runnable(Workqueue*)
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{
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if (!this->symtab_lock_->is_writable() || this->object_->is_locked())
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return IS_LOCKED;
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return IS_RUNNABLE;
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}
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// Return the locks we hold: one on the file, one on the symbol table
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// and one blocker.
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class Scan_relocs::Scan_relocs_locker : public Task_locker
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{
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public:
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Scan_relocs_locker(Object* object, Task_token& symtab_lock, Task* task,
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Task_token& blocker, Workqueue* workqueue)
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: objlock_(*object), symtab_locker_(symtab_lock, task),
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blocker_(blocker, workqueue)
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{ }
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private:
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Task_locker_obj<Object> objlock_;
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Task_locker_write symtab_locker_;
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Task_locker_block blocker_;
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};
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Task_locker*
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Scan_relocs::locks(Workqueue* workqueue)
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{
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return new Scan_relocs_locker(this->object_, *this->symtab_lock_, this,
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*this->blocker_, workqueue);
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}
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// Scan the relocs.
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void
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Scan_relocs::run(Workqueue*)
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{
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this->object_->scan_relocs(this->options_, this->symtab_, this->layout_,
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this->rd_);
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delete this->rd_;
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this->rd_ = NULL;
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}
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// Relocate_task methods.
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// These tasks are always runnable.
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Task::Is_runnable_type
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Relocate_task::is_runnable(Workqueue*)
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{
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return IS_RUNNABLE;
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}
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// We want to lock the file while we run. We want to unblock
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// FINAL_BLOCKER when we are done.
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class Relocate_task::Relocate_locker : public Task_locker
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{
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public:
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Relocate_locker(Task_token& token, Workqueue* workqueue,
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Object* object)
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: blocker_(token, workqueue), objlock_(*object)
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{ }
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private:
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Task_locker_block blocker_;
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Task_locker_obj<Object> objlock_;
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};
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Task_locker*
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Relocate_task::locks(Workqueue* workqueue)
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{
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return new Relocate_locker(*this->final_blocker_, workqueue,
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this->object_);
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}
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// Run the task.
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void
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Relocate_task::run(Workqueue*)
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{
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this->object_->relocate(this->options_, this->symtab_, this->layout_,
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this->of_);
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}
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// Read the relocs and local symbols from the object file and store
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// the information in RD.
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template<int size, bool big_endian>
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void
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Sized_relobj<size, big_endian>::do_read_relocs(Read_relocs_data* rd)
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{
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rd->relocs.clear();
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unsigned int shnum = this->shnum();
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if (shnum == 0)
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return;
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rd->relocs.reserve(shnum / 2);
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const unsigned char *pshdrs = this->get_view(this->shoff_,
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shnum * This::shdr_size);
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// Skip the first, dummy, section.
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const unsigned char *ps = pshdrs + This::shdr_size;
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for (unsigned int i = 1; i < shnum; ++i, ps += This::shdr_size)
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{
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typename This::Shdr shdr(ps);
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unsigned int sh_type = shdr.get_sh_type();
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if (sh_type != elfcpp::SHT_REL && sh_type != elfcpp::SHT_RELA)
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continue;
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unsigned int shndx = shdr.get_sh_info();
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if (shndx >= shnum)
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{
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fprintf(stderr, _("%s: %s: relocation section %u has bad info %u\n"),
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program_name, this->name().c_str(), i, shndx);
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gold_exit(false);
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}
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if (!this->is_section_included(shndx))
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continue;
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// We are scanning relocations in order to fill out the GOT and
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// PLT sections. Relocations for sections which are not
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// allocated (typically debugging sections) should not add new
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// GOT and PLT entries. So we skip them.
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typename This::Shdr secshdr(pshdrs + shndx * This::shdr_size);
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if ((secshdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
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continue;
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if (shdr.get_sh_link() != this->symtab_shnum_)
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{
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fprintf(stderr,
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_("%s: %s: relocation section %u uses unexpected "
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"symbol table %u\n"),
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program_name, this->name().c_str(), i, shdr.get_sh_link());
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gold_exit(false);
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}
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off_t sh_size = shdr.get_sh_size();
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unsigned int reloc_size;
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if (sh_type == elfcpp::SHT_REL)
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reloc_size = elfcpp::Elf_sizes<size>::rel_size;
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else
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reloc_size = elfcpp::Elf_sizes<size>::rela_size;
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if (reloc_size != shdr.get_sh_entsize())
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{
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fprintf(stderr,
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_("%s: %s: unexpected entsize for reloc section %u: "
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"%lu != %u"),
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program_name, this->name().c_str(), i,
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static_cast<unsigned long>(shdr.get_sh_entsize()),
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reloc_size);
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gold_exit(false);
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}
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size_t reloc_count = sh_size / reloc_size;
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if (reloc_count * reloc_size != sh_size)
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{
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fprintf(stderr, _("%s: %s: reloc section %u size %lu uneven"),
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program_name, this->name().c_str(), i,
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static_cast<unsigned long>(sh_size));
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gold_exit(false);
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}
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rd->relocs.push_back(Section_relocs());
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Section_relocs& sr(rd->relocs.back());
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sr.reloc_shndx = i;
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sr.data_shndx = shndx;
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sr.contents = this->get_lasting_view(shdr.get_sh_offset(), sh_size);
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sr.sh_type = sh_type;
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sr.reloc_count = reloc_count;
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}
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// Read the local symbols.
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if (this->symtab_shnum_ == 0 || this->local_symbol_count_ == 0)
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rd->local_symbols = NULL;
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else
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{
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typename This::Shdr symtabshdr(pshdrs
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+ this->symtab_shnum_ * This::shdr_size);
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assert(symtabshdr.get_sh_type() == elfcpp::SHT_SYMTAB);
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const int sym_size = This::sym_size;
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const unsigned int loccount = this->local_symbol_count_;
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assert(loccount == symtabshdr.get_sh_info());
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off_t locsize = loccount * sym_size;
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rd->local_symbols = this->get_lasting_view(symtabshdr.get_sh_offset(),
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locsize);
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}
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}
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// Scan the relocs and adjust the symbol table. This looks for
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// relocations which require GOT/PLT/COPY relocations.
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template<int size, bool big_endian>
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void
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Sized_relobj<size, big_endian>::do_scan_relocs(const General_options& options,
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Symbol_table* symtab,
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Layout* layout,
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Read_relocs_data* rd)
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{
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Sized_target<size, big_endian>* target = this->sized_target();
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const unsigned char* local_symbols;
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if (rd->local_symbols == NULL)
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local_symbols = NULL;
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else
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local_symbols = rd->local_symbols->data();
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for (Read_relocs_data::Relocs_list::iterator p = rd->relocs.begin();
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p != rd->relocs.end();
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++p)
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{
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target->scan_relocs(options, symtab, layout, this, p->sh_type,
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p->contents->data(), p->reloc_count,
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this->local_symbol_count_,
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local_symbols,
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this->symbols_);
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delete p->contents;
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p->contents = NULL;
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}
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if (rd->local_symbols != NULL)
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{
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delete rd->local_symbols;
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rd->local_symbols = NULL;
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}
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}
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// Relocate the input sections and write out the local symbols.
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template<int size, bool big_endian>
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void
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Sized_relobj<size, big_endian>::do_relocate(const General_options& options,
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const Symbol_table* symtab,
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const Layout* layout,
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Output_file* of)
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{
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unsigned int shnum = this->shnum();
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// Read the section headers.
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const unsigned char* pshdrs = this->get_view(this->shoff_,
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shnum * This::shdr_size);
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Views views;
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views.resize(shnum);
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// Make two passes over the sections. The first one copies the
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// section data to the output file. The second one applies
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// relocations.
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this->write_sections(pshdrs, of, &views);
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// Apply relocations.
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this->relocate_sections(options, symtab, layout, pshdrs, &views);
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// Write out the accumulated views.
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for (unsigned int i = 1; i < shnum; ++i)
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{
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if (views[i].view != NULL)
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of->write_output_view(views[i].offset, views[i].view_size,
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views[i].view);
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}
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// Write out the local symbols.
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this->write_local_symbols(of, layout->sympool());
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}
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// Write section data to the output file. PSHDRS points to the
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// section headers. Record the views in *PVIEWS for use when
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// relocating.
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template<int size, bool big_endian>
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void
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Sized_relobj<size, big_endian>::write_sections(const unsigned char* pshdrs,
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Output_file* of,
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Views* pviews)
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{
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unsigned int shnum = this->shnum();
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std::vector<Map_to_output>& map_sections(this->map_to_output());
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const unsigned char* p = pshdrs + This::shdr_size;
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for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
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{
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View_size* pvs = &(*pviews)[i];
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pvs->view = NULL;
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const Output_section* os = map_sections[i].output_section;
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if (os == NULL)
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continue;
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typename This::Shdr shdr(p);
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if (shdr.get_sh_type() == elfcpp::SHT_NOBITS)
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continue;
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off_t start = os->offset() + map_sections[i].offset;
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off_t sh_size = shdr.get_sh_size();
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if (sh_size == 0)
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continue;
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assert(map_sections[i].offset >= 0
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&& map_sections[i].offset + sh_size <= os->data_size());
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unsigned char* view = of->get_output_view(start, sh_size);
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this->read(shdr.get_sh_offset(), sh_size, view);
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pvs->view = view;
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pvs->address = os->address() + map_sections[i].offset;
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pvs->offset = start;
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pvs->view_size = sh_size;
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}
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}
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// Relocate section data. VIEWS points to the section data as views
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// in the output file.
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template<int size, bool big_endian>
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void
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Sized_relobj<size, big_endian>::relocate_sections(
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const General_options& options,
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const Symbol_table* symtab,
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const Layout* layout,
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const unsigned char* pshdrs,
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Views* pviews)
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{
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unsigned int shnum = this->shnum();
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Sized_target<size, big_endian>* target = this->sized_target();
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Relocate_info<size, big_endian> relinfo;
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relinfo.options = &options;
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relinfo.symtab = symtab;
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relinfo.layout = layout;
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relinfo.object = this;
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relinfo.local_symbol_count = this->local_symbol_count_;
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relinfo.values = this->values_;
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relinfo.symbols = this->symbols_;
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const unsigned char* p = pshdrs + This::shdr_size;
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for (unsigned int i = 1; i < shnum; ++i, p += This::shdr_size)
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{
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typename This::Shdr shdr(p);
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unsigned int sh_type = shdr.get_sh_type();
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if (sh_type != elfcpp::SHT_REL && sh_type != elfcpp::SHT_RELA)
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continue;
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unsigned int index = shdr.get_sh_info();
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if (index >= this->shnum())
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{
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fprintf(stderr, _("%s: %s: relocation section %u has bad info %u\n"),
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program_name, this->name().c_str(), i, index);
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gold_exit(false);
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}
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if (!this->is_section_included(index))
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{
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// This relocation section is against a section which we
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// discarded.
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continue;
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}
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assert((*pviews)[index].view != NULL);
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if (shdr.get_sh_link() != this->symtab_shnum_)
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{
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fprintf(stderr,
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_("%s: %s: relocation section %u uses unexpected "
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"symbol table %u\n"),
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program_name, this->name().c_str(), i, shdr.get_sh_link());
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gold_exit(false);
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}
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off_t sh_size = shdr.get_sh_size();
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const unsigned char* prelocs = this->get_view(shdr.get_sh_offset(),
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sh_size);
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unsigned int reloc_size;
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if (sh_type == elfcpp::SHT_REL)
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reloc_size = elfcpp::Elf_sizes<size>::rel_size;
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else
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reloc_size = elfcpp::Elf_sizes<size>::rela_size;
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if (reloc_size != shdr.get_sh_entsize())
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{
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fprintf(stderr,
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_("%s: %s: unexpected entsize for reloc section %u: "
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"%lu != %u"),
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program_name, this->name().c_str(), i,
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static_cast<unsigned long>(shdr.get_sh_entsize()),
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reloc_size);
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gold_exit(false);
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}
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size_t reloc_count = sh_size / reloc_size;
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if (reloc_count * reloc_size != sh_size)
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{
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fprintf(stderr, _("%s: %s: reloc section %u size %lu uneven"),
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program_name, this->name().c_str(), i,
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static_cast<unsigned long>(sh_size));
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gold_exit(false);
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}
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relinfo.reloc_shndx = i;
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relinfo.data_shndx = index;
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target->relocate_section(&relinfo,
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sh_type,
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prelocs,
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reloc_count,
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(*pviews)[index].view,
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(*pviews)[index].address,
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(*pviews)[index].view_size);
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}
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}
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// Instantiate the templates we need. We could use the configure
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// script to restrict this to only the ones for implemented targets.
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template
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void
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Sized_relobj<32, false>::do_read_relocs(Read_relocs_data* rd);
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template
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void
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Sized_relobj<32, true>::do_read_relocs(Read_relocs_data* rd);
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template
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void
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Sized_relobj<64, false>::do_read_relocs(Read_relocs_data* rd);
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template
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void
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Sized_relobj<64, true>::do_read_relocs(Read_relocs_data* rd);
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template
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void
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Sized_relobj<32, false>::do_scan_relocs(const General_options& options,
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Symbol_table* symtab,
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Layout* layout,
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Read_relocs_data* rd);
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template
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void
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Sized_relobj<32, true>::do_scan_relocs(const General_options& options,
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Symbol_table* symtab,
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Layout* layout,
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Read_relocs_data* rd);
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template
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void
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Sized_relobj<64, false>::do_scan_relocs(const General_options& options,
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Symbol_table* symtab,
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Layout* layout,
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Read_relocs_data* rd);
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template
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void
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Sized_relobj<64, true>::do_scan_relocs(const General_options& options,
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Symbol_table* symtab,
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Layout* layout,
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Read_relocs_data* rd);
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template
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void
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Sized_relobj<32, false>::do_relocate(const General_options& options,
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const Symbol_table* symtab,
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const Layout* layout,
|
|
Output_file* of);
|
|
|
|
template
|
|
void
|
|
Sized_relobj<32, true>::do_relocate(const General_options& options,
|
|
const Symbol_table* symtab,
|
|
const Layout* layout,
|
|
Output_file* of);
|
|
|
|
template
|
|
void
|
|
Sized_relobj<64, false>::do_relocate(const General_options& options,
|
|
const Symbol_table* symtab,
|
|
const Layout* layout,
|
|
Output_file* of);
|
|
|
|
template
|
|
void
|
|
Sized_relobj<64, true>::do_relocate(const General_options& options,
|
|
const Symbol_table* symtab,
|
|
const Layout* layout,
|
|
Output_file* of);
|
|
|
|
|
|
} // End namespace gold.
|