// x86_64.cc -- x86_64 target support for gold.
-// Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
+// Copyright 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
#include "symtab.h"
#include "layout.h"
#include "output.h"
+#include "copy-relocs.h"
#include "target.h"
#include "target-reloc.h"
#include "target-select.h"
Target_x86_64()
: Sized_target<64, false>(&x86_64_info),
got_(NULL), plt_(NULL), got_plt_(NULL), rela_dyn_(NULL),
- copy_relocs_(NULL), dynbss_(NULL), got_mod_index_offset_(-1U)
+ copy_relocs_(elfcpp::R_X86_64_COPY), dynbss_(NULL),
+ got_mod_index_offset_(-1U), tls_base_symbol_defined_(false)
{ }
+ // Scan the relocations to look for symbol adjustments.
+ void
+ gc_process_relocs(const General_options& options,
+ Symbol_table* symtab,
+ Layout* layout,
+ Sized_relobj<64, false>* 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,
// Return whether SYM is defined by the ABI.
bool
- do_is_defined_by_abi(Symbol* sym) const
+ do_is_defined_by_abi(const Symbol* sym) const
{ return strcmp(sym->name(), "__tls_get_addr") == 0; }
// Return the size of the GOT section.
{
public:
Relocate()
- : skip_call_tls_get_addr_(false)
+ : skip_call_tls_get_addr_(false), saw_tls_block_reloc_(false)
{ }
~Relocate()
// Do a relocation. Return false if the caller should not issue
// any warnings about this relocation.
inline bool
- relocate(const Relocate_info<64, false>*, Target_x86_64*, size_t relnum,
- const elfcpp::Rela<64, false>&,
+ relocate(const Relocate_info<64, false>*, Target_x86_64*, Output_section*,
+ size_t relnum, const elfcpp::Rela<64, false>&,
unsigned int r_type, const Sized_symbol<64>*,
const Symbol_value<64>*,
unsigned char*, elfcpp::Elf_types<64>::Elf_Addr,
// This is set if we should skip the next reloc, which should be a
// PLT32 reloc against ___tls_get_addr.
bool skip_call_tls_get_addr_;
+
+ // This is set if we see a relocation which could load the address
+ // of the TLS block. Whether we see such a relocation determines
+ // how we handle the R_X86_64_DTPOFF32 relocation, which is used
+ // in debugging sections.
+ bool saw_tls_block_reloc_;
};
// A class which returns the size required for a relocation type,
void
make_plt_entry(Symbol_table*, Layout*, Symbol*);
+ // Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
+ void
+ define_tls_base_symbol(Symbol_table*, Layout*);
+
// Create the reserved PLT and GOT entries for the TLS descriptor resolver.
void
reserve_tlsdesc_entries(Symbol_table* symtab, Layout* layout);
&& gsym->type() != elfcpp::STT_FUNC);
}
- // Copy a relocation against a global symbol.
+ // Add a potential copy relocation.
void
- copy_reloc(const General_options*, Symbol_table*, Layout*,
- Sized_relobj<64, false>*, unsigned int,
- Output_section*, Symbol*, const elfcpp::Rela<64, false>&);
+ copy_reloc(Symbol_table* symtab, Layout* layout,
+ Sized_relobj<64, false>* object,
+ unsigned int shndx, Output_section* output_section,
+ Symbol* sym, const elfcpp::Rela<64, false>& reloc)
+ {
+ this->copy_relocs_.copy_reloc(symtab, layout,
+ symtab->get_sized_symbol<64>(sym),
+ object, shndx, output_section,
+ reloc, this->rela_dyn_section(layout));
+ }
// Information about this specific target which we pass to the
// general Target structure.
// The dynamic reloc section.
Reloc_section* rela_dyn_;
// Relocs saved to avoid a COPY reloc.
- Copy_relocs<64, false>* copy_relocs_;
+ Copy_relocs<elfcpp::SHT_RELA, 64, false> copy_relocs_;
// Space for variables copied with a COPY reloc.
Output_data_space* dynbss_;
// Offset of the GOT entry for the TLS module index.
unsigned int got_mod_index_offset_;
+ // True if the _TLS_MODULE_BASE_ symbol has been defined.
+ bool tls_base_symbol_defined_;
};
const Target::Target_info Target_x86_64::x86_64_info =
this->got_ = new Output_data_got<64, false>();
- layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
- elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
- this->got_);
+ Output_section* os;
+ os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
+ (elfcpp::SHF_ALLOC
+ | elfcpp::SHF_WRITE),
+ this->got_);
+ os->set_is_relro();
// The old GNU linker creates a .got.plt section. We just
// create another set of data in the .got section. Note that we
// always create a PLT if we create a GOT, although the PLT
// might be empty.
- this->got_plt_ = new Output_data_space(8);
- layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
- elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
- this->got_plt_);
+ this->got_plt_ = new Output_data_space(8, "** GOT PLT");
+ os = layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
+ (elfcpp::SHF_ALLOC
+ | elfcpp::SHF_WRITE),
+ this->got_plt_);
+ os->set_is_relro();
// The first three entries are reserved.
this->got_plt_->set_current_data_size(3 * 8);
if (this->rela_dyn_ == NULL)
{
gold_assert(layout != NULL);
- this->rela_dyn_ = new Reloc_section();
+ this->rela_dyn_ = new Reloc_section(parameters->options().combreloc());
layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
elfcpp::SHF_ALLOC, this->rela_dyn_);
}
void
do_adjust_output_section(Output_section* os);
+ // Write to a map file.
+ void
+ do_print_to_mapfile(Mapfile* mapfile) const
+ { mapfile->print_output_data(this, _("** PLT")); }
+
private:
// The size of an entry in the PLT.
static const int plt_entry_size = 16;
: Output_section_data(8), got_(got), got_plt_(got_plt), count_(0),
tlsdesc_got_offset_(-1U)
{
- this->rel_ = new Reloc_section();
+ this->rel_ = new Reloc_section(false);
layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
elfcpp::SHF_ALLOC, this->rel_);
}
unsigned char* pov = oview;
// The base address of the .plt section.
- elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
+ elfcpp::Elf_types<64>::Elf_Addr plt_address = this->address();
// The base address of the .got section.
- elfcpp::Elf_types<32>::Elf_Addr got_base = this->got_->address();
+ elfcpp::Elf_types<64>::Elf_Addr got_base = this->got_->address();
// The base address of the PLT portion of the .got section,
// which is where the GOT pointer will point, and where the
// three reserved GOT entries are located.
- elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
+ elfcpp::Elf_types<64>::Elf_Addr got_address = this->got_plt_->address();
memcpy(pov, first_plt_entry, plt_entry_size);
// We do a jmp relative to the PC at the end of this instruction.
- elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_address + 8
- - (plt_address + 6));
- elfcpp::Swap<32, false>::writeval(pov + 8, got_address + 16
- - (plt_address + 12));
+ elfcpp::Swap_unaligned<32, false>::writeval(pov + 2,
+ (got_address + 8
+ - (plt_address + 6)));
+ elfcpp::Swap<32, false>::writeval(pov + 8,
+ (got_address + 16
+ - (plt_address + 12)));
pov += plt_entry_size;
unsigned char* got_pov = got_view;
this->plt_->add_entry(gsym);
}
+// Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
+
+void
+Target_x86_64::define_tls_base_symbol(Symbol_table* symtab, Layout* layout)
+{
+ if (this->tls_base_symbol_defined_)
+ return;
+
+ Output_segment* tls_segment = layout->tls_segment();
+ if (tls_segment != NULL)
+ {
+ bool is_exec = parameters->options().output_is_executable();
+ symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
+ tls_segment, 0, 0,
+ elfcpp::STT_TLS,
+ elfcpp::STB_LOCAL,
+ elfcpp::STV_HIDDEN, 0,
+ (is_exec
+ ? Symbol::SEGMENT_END
+ : Symbol::SEGMENT_START),
+ true);
+ }
+ this->tls_base_symbol_defined_ = true;
+}
+
// Create the reserved PLT and GOT entries for the TLS descriptor resolver.
void
unsigned int got_offset = got->add_constant(0);
rela_dyn->add_local(object, 0, elfcpp::R_X86_64_DTPMOD64, got,
got_offset, 0);
+ got->add_constant(0);
this->got_mod_index_offset_ = got_offset;
}
return this->got_mod_index_offset_;
}
-// Handle a relocation against a non-function symbol defined in a
-// dynamic object. The traditional way to handle this is to generate
-// a COPY relocation to copy the variable at runtime from the shared
-// object into the executable's data segment. However, this is
-// undesirable in general, as if the size of the object changes in the
-// dynamic object, the executable will no longer work correctly. If
-// this relocation is in a writable section, then we can create a
-// dynamic reloc and the dynamic linker will resolve it to the correct
-// address at runtime. However, we do not want do that if the
-// relocation is in a read-only section, as it would prevent the
-// readonly segment from being shared. And if we have to eventually
-// generate a COPY reloc, then any dynamic relocations will be
-// useless. So this means that if this is a writable section, we need
-// to save the relocation until we see whether we have to create a
-// COPY relocation for this symbol for any other relocation.
-
-void
-Target_x86_64::copy_reloc(const General_options* options,
- Symbol_table* symtab,
- Layout* layout,
- Sized_relobj<64, false>* object,
- unsigned int data_shndx,
- Output_section* output_section,
- Symbol* gsym,
- const elfcpp::Rela<64, false>& rela)
-{
- Sized_symbol<64>* ssym = symtab->get_sized_symbol<64>(gsym);
-
- if (!Copy_relocs<64, false>::need_copy_reloc(options, object,
- data_shndx, ssym))
- {
- // So far we do not need a COPY reloc. Save this relocation.
- // If it turns out that we never need a COPY reloc for this
- // symbol, then we will emit the relocation.
- if (this->copy_relocs_ == NULL)
- this->copy_relocs_ = new Copy_relocs<64, false>();
- this->copy_relocs_->save(ssym, object, data_shndx, output_section, rela);
- }
- else
- {
- // Allocate space for this symbol in the .bss section.
-
- elfcpp::Elf_types<64>::Elf_WXword symsize = ssym->symsize();
-
- // There is no defined way to determine the required alignment
- // of the symbol. We pick the alignment based on the size. We
- // set an arbitrary maximum of 256.
- unsigned int align;
- for (align = 1; align < 512; align <<= 1)
- if ((symsize & align) != 0)
- break;
-
- if (this->dynbss_ == NULL)
- {
- this->dynbss_ = new Output_data_space(align);
- layout->add_output_section_data(".bss",
- elfcpp::SHT_NOBITS,
- (elfcpp::SHF_ALLOC
- | elfcpp::SHF_WRITE),
- this->dynbss_);
- }
-
- Output_data_space* dynbss = this->dynbss_;
-
- if (align > dynbss->addralign())
- dynbss->set_space_alignment(align);
-
- section_size_type dynbss_size = dynbss->current_data_size();
- dynbss_size = align_address(dynbss_size, align);
- section_size_type offset = dynbss_size;
- dynbss->set_current_data_size(dynbss_size + symsize);
-
- symtab->define_with_copy_reloc(ssym, dynbss, offset);
-
- // Add the COPY reloc.
- Reloc_section* rela_dyn = this->rela_dyn_section(layout);
- rela_dyn->add_global(ssym, elfcpp::R_X86_64_COPY, dynbss, offset, 0);
- }
-}
-
-
// Optimize the TLS relocation type based on what we know about the
// symbol. IS_FINAL is true if the final address of this symbol is
// known at link time.
this->check_non_pic(object, r_type);
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
+ unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
if (lsym.get_st_type() != elfcpp::STT_SECTION)
- {
- unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
- rela_dyn->add_local(object, r_sym, r_type, output_section,
- data_shndx, reloc.get_r_offset(),
- reloc.get_r_addend());
- }
+ rela_dyn->add_local(object, r_sym, r_type, output_section,
+ data_shndx, reloc.get_r_offset(),
+ reloc.get_r_addend());
else
{
gold_assert(lsym.get_st_value() == 0);
- rela_dyn->add_local_section(object, lsym.get_st_shndx(),
- r_type, output_section,
- data_shndx, reloc.get_r_offset(),
- reloc.get_r_addend());
+ unsigned int shndx = lsym.get_st_shndx();
+ bool is_ordinary;
+ shndx = object->adjust_sym_shndx(r_sym, shndx,
+ &is_ordinary);
+ if (!is_ordinary)
+ object->error(_("section symbol %u has bad shndx %u"),
+ r_sym, shndx);
+ else
+ rela_dyn->add_local_section(object, shndx,
+ r_type, output_section,
+ data_shndx, reloc.get_r_offset(),
+ reloc.get_r_addend());
}
}
break;
Output_data_got<64, false>* got
= target->got_section(symtab, layout);
unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
- got->add_local_pair_with_rela(object, r_sym,
- lsym.get_st_shndx(),
- GOT_TYPE_TLS_PAIR,
- target->rela_dyn_section(layout),
- elfcpp::R_X86_64_DTPMOD64, 0);
+ unsigned int shndx = lsym.get_st_shndx();
+ bool is_ordinary;
+ shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
+ if (!is_ordinary)
+ object->error(_("local symbol %u has bad shndx %u"),
+ r_sym, shndx);
+ else
+ got->add_local_pair_with_rela(object, r_sym,
+ shndx,
+ GOT_TYPE_TLS_PAIR,
+ target->rela_dyn_section(layout),
+ elfcpp::R_X86_64_DTPMOD64, 0);
}
else if (optimized_type != tls::TLSOPT_TO_LE)
unsupported_reloc_local(object, r_type);
break;
case elfcpp::R_X86_64_GOTPC32_TLSDESC:
+ target->define_tls_base_symbol(symtab, layout);
if (optimized_type == tls::TLSOPT_NONE)
{
// Create reserved PLT and GOT entries for the resolver.
Output_data_got<64, false>* got
= target->got_section(symtab, layout);
unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
- got->add_local_pair_with_rela(object, r_sym,
- lsym.get_st_shndx(),
- GOT_TYPE_TLS_DESC,
- target->rela_dyn_section(layout),
- elfcpp::R_X86_64_TLSDESC, 0);
+ unsigned int shndx = lsym.get_st_shndx();
+ bool is_ordinary;
+ shndx = object->adjust_sym_shndx(r_sym, shndx, &is_ordinary);
+ if (!is_ordinary)
+ object->error(_("local symbol %u has bad shndx %u"),
+ r_sym, shndx);
+ else
+ got->add_local_pair_with_rela(object, r_sym,
+ shndx,
+ GOT_TYPE_TLS_DESC,
+ target->rela_dyn_section(layout),
+ elfcpp::R_X86_64_TLSDESC, 0);
}
else if (optimized_type != tls::TLSOPT_TO_LE)
unsupported_reloc_local(object, r_type);
// Scan a relocation for a global symbol.
inline void
-Target_x86_64::Scan::global(const General_options& options,
+Target_x86_64::Scan::global(const General_options&,
Symbol_table* symtab,
Layout* layout,
Target_x86_64* target,
{
if (target->may_need_copy_reloc(gsym))
{
- target->copy_reloc(&options, symtab, layout, object,
+ target->copy_reloc(symtab, layout, object,
data_shndx, output_section, gsym, reloc);
}
else if (r_type == elfcpp::R_X86_64_64
{
if (target->may_need_copy_reloc(gsym))
{
- target->copy_reloc(&options, symtab, layout, object,
+ target->copy_reloc(symtab, layout, object,
data_shndx, output_section, gsym, reloc);
}
else
break;
case elfcpp::R_X86_64_GOTPC32_TLSDESC:
+ target->define_tls_base_symbol(symtab, layout);
if (optimized_type == tls::TLSOPT_NONE)
{
// Create reserved PLT and GOT entries for the resolver.
}
}
+void
+Target_x86_64::gc_process_relocs(const General_options& options,
+ Symbol_table* symtab,
+ Layout* layout,
+ Sized_relobj<64, false>* 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)
+{
+
+ if (sh_type == elfcpp::SHT_REL)
+ {
+ return;
+ }
+
+ gold::gc_process_relocs<64, false, Target_x86_64, elfcpp::SHT_RELA,
+ Target_x86_64::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.
void
// Emit any relocs we saved in an attempt to avoid generating COPY
// relocs.
- if (this->copy_relocs_ == NULL)
- return;
- if (this->copy_relocs_->any_to_emit())
- {
- Reloc_section* rela_dyn = this->rela_dyn_section(layout);
- this->copy_relocs_->emit(rela_dyn);
- }
- delete this->copy_relocs_;
- this->copy_relocs_ = NULL;
+ if (this->copy_relocs_.any_saved_relocs())
+ this->copy_relocs_.emit(this->rela_dyn_section(layout));
}
// Perform a relocation.
inline bool
Target_x86_64::Relocate::relocate(const Relocate_info<64, false>* relinfo,
Target_x86_64* target,
+ Output_section*,
size_t relnum,
const elfcpp::Rela<64, false>& rela,
unsigned int r_type,
{
if (this->skip_call_tls_get_addr_)
{
- if (r_type != elfcpp::R_X86_64_PLT32
+ if ((r_type != elfcpp::R_X86_64_PLT32
+ && r_type != elfcpp::R_X86_64_PC32)
|| gsym == NULL
|| strcmp(gsym->name(), "__tls_get_addr") != 0)
{
// Pick the value to use for symbols defined in shared objects.
Symbol_value<64> symval;
if (gsym != NULL
- && (gsym->is_from_dynobj()
- || (parameters->options().shared()
- && (gsym->is_undefined() || gsym->is_preemptible())))
- && gsym->has_plt_offset())
+ && gsym->use_plt_offset(r_type == elfcpp::R_X86_64_PC64
+ || r_type == elfcpp::R_X86_64_PC32
+ || r_type == elfcpp::R_X86_64_PC16
+ || r_type == elfcpp::R_X86_64_PC8))
{
symval.set_output_value(target->plt_section()->address()
+ gsym->plt_offset());
switch (r_type)
{
case elfcpp::R_X86_64_TLSGD: // Global-dynamic
+ this->saw_tls_block_reloc_ = true;
if (optimized_type == tls::TLSOPT_TO_LE)
{
gold_assert(tls_segment != NULL);
case elfcpp::R_X86_64_GOTPC32_TLSDESC: // Global-dynamic (from ~oliva url)
case elfcpp::R_X86_64_TLSDESC_CALL:
+ this->saw_tls_block_reloc_ = true;
if (optimized_type == tls::TLSOPT_TO_LE)
{
gold_assert(tls_segment != NULL);
break;
case elfcpp::R_X86_64_TLSLD: // Local-dynamic
+ this->saw_tls_block_reloc_ = true;
if (optimized_type == tls::TLSOPT_TO_LE)
{
gold_assert(tls_segment != NULL);
case elfcpp::R_X86_64_DTPOFF32:
gold_assert(tls_segment != NULL);
if (optimized_type == tls::TLSOPT_TO_LE)
- value -= tls_segment->memsz();
- Relocate_functions<64, false>::rela32(view, value, 0);
+ {
+ // This relocation type is used in debugging information.
+ // In that case we need to not optimize the value. If we
+ // haven't seen a TLSLD reloc, then we assume we should not
+ // optimize this reloc.
+ if (this->saw_tls_block_reloc_)
+ value -= tls_segment->memsz();
+ }
+ Relocate_functions<64, false>::rela32(view, value, addend);
break;
case elfcpp::R_X86_64_DTPOFF64:
gold_assert(tls_segment != NULL);
if (optimized_type == tls::TLSOPT_TO_LE)
- value -= tls_segment->memsz();
- Relocate_functions<64, false>::rela64(view, value, 0);
+ {
+ // See R_X86_64_DTPOFF32, just above, for why we test this.
+ if (this->saw_tls_block_reloc_)
+ value -= tls_segment->memsz();
+ }
+ Relocate_functions<64, false>::rela64(view, value, addend);
break;
case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
case elfcpp::R_X86_64_TPOFF32: // Local-exec
value -= tls_segment->memsz();
- Relocate_functions<64, false>::rela32(view, value, 0);
+ Relocate_functions<64, false>::rela32(view, value, addend);
break;
}
}
projects / deliverable / binutils-gdb.git / blobdiff