// x86_64.cc -- x86_64 target support for gold.
-// Copyright 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
+// Copyright 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
#include <cstring>
#include "elfcpp.h"
+#include "dwarf.h"
#include "parameters.h"
#include "reloc.h"
#include "x86_64.h"
public:
typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
- Output_data_plt_x86_64(Symbol_table* symtab, Layout* layout,
- Output_data_got<64, false>* got,
- Output_data_space* got_plt)
- : Output_section_data(8), tlsdesc_rel_(NULL), got_(got), got_plt_(got_plt),
- count_(0), tlsdesc_got_offset_(-1U), free_list_()
- { this->init(symtab, layout); }
-
- Output_data_plt_x86_64(Symbol_table* symtab, Layout* layout,
- Output_data_got<64, false>* got,
+ Output_data_plt_x86_64(Layout* layout, Output_data_got<64, false>* got,
+ Output_data_space* got_plt,
+ Output_data_space* got_irelative)
+ : Output_section_data(16), layout_(layout), tlsdesc_rel_(NULL),
+ irelative_rel_(NULL), got_(got), got_plt_(got_plt),
+ got_irelative_(got_irelative), count_(0), irelative_count_(0),
+ tlsdesc_got_offset_(-1U), free_list_()
+ { this->init(layout); }
+
+ Output_data_plt_x86_64(Layout* layout, Output_data_got<64, false>* got,
Output_data_space* got_plt,
+ Output_data_space* got_irelative,
unsigned int plt_count)
- : Output_section_data((plt_count + 1) * plt_entry_size, 8, false),
- tlsdesc_rel_(NULL), got_(got), got_plt_(got_plt),
- count_(plt_count), tlsdesc_got_offset_(-1U), free_list_()
+ : Output_section_data((plt_count + 1) * plt_entry_size, 16, false),
+ layout_(layout), tlsdesc_rel_(NULL), irelative_rel_(NULL), got_(got),
+ got_plt_(got_plt), got_irelative_(got_irelative), count_(plt_count),
+ irelative_count_(0), tlsdesc_got_offset_(-1U), free_list_()
{
- this->init(symtab, layout);
+ this->init(layout);
// Initialize the free list and reserve the first entry.
this->free_list_.init((plt_count + 1) * plt_entry_size, false);
// Initialize the PLT section.
void
- init(Symbol_table* symtab, Layout* layout);
+ init(Layout* layout);
// Add an entry to the PLT.
void
- add_entry(Symbol* gsym);
+ add_entry(Symbol_table*, Layout*, Symbol* gsym);
// Add an entry to the PLT for a local STT_GNU_IFUNC symbol.
unsigned int
- add_local_ifunc_entry(Sized_relobj_file<64, false>* relobj,
+ add_local_ifunc_entry(Symbol_table* symtab, Layout*,
+ Sized_relobj_file<64, false>* relobj,
unsigned int local_sym_index);
// Add the relocation for a PLT entry.
void
- add_relocation(Symbol* gsym, unsigned int got_offset);
+ add_relocation(Symbol_table*, Layout*, Symbol* gsym,
+ unsigned int got_offset);
// Add the reserved TLSDESC_PLT entry to the PLT.
void
// Return the offset of the reserved TLSDESC_PLT entry.
unsigned int
get_tlsdesc_plt_offset() const
- { return (this->count_ + 1) * plt_entry_size; }
+ { return (this->count_ + this->irelative_count_ + 1) * plt_entry_size; }
// Return the .rela.plt section data.
Reloc_section*
Reloc_section*
rela_tlsdesc(Layout*);
+ // Return where the IRELATIVE relocations should go in the PLT
+ // relocations.
+ Reloc_section*
+ rela_irelative(Symbol_table*, Layout*);
+
+ // Return whether we created a section for IRELATIVE relocations.
+ bool
+ has_irelative_section() const
+ { return this->irelative_rel_ != NULL; }
+
// Return the number of PLT entries.
unsigned int
entry_count() const
- { return this->count_; }
+ { return this->count_ + this->irelative_count_; }
// Return the offset of the first non-reserved PLT entry.
static unsigned int
(plt_index + 2) * plt_entry_size);
}
+ // Return the PLT address to use for a global symbol.
+ uint64_t
+ address_for_global(const Symbol*);
+
+ // Return the PLT address to use for a local symbol.
+ uint64_t
+ address_for_local(const Relobj*, unsigned int symndx);
+
protected:
void
do_adjust_output_section(Output_section* os);
// The first entry in the PLT.
// From the AMD64 ABI: "Unlike Intel386 ABI, this ABI uses the same
// procedure linkage table for both programs and shared objects."
- static unsigned char first_plt_entry[plt_entry_size];
+ static const unsigned char first_plt_entry[plt_entry_size];
// Other entries in the PLT for an executable.
- static unsigned char plt_entry[plt_entry_size];
+ static const unsigned char plt_entry[plt_entry_size];
// The reserved TLSDESC entry in the PLT for an executable.
- static unsigned char tlsdesc_plt_entry[plt_entry_size];
+ static const unsigned char tlsdesc_plt_entry[plt_entry_size];
+
+ // The .eh_frame unwind information for the PLT.
+ static const int plt_eh_frame_cie_size = 16;
+ static const int plt_eh_frame_fde_size = 32;
+ static const unsigned char plt_eh_frame_cie[plt_eh_frame_cie_size];
+ static const unsigned char plt_eh_frame_fde[plt_eh_frame_fde_size];
// Set the final size.
void
void
do_write(Output_file*);
+ // A pointer to the Layout class, so that we can find the .dynamic
+ // section when we write out the GOT PLT section.
+ Layout* layout_;
// The reloc section.
Reloc_section* rel_;
// The TLSDESC relocs, if necessary. These must follow the regular
// PLT relocs.
Reloc_section* tlsdesc_rel_;
+ // The IRELATIVE relocs, if necessary. These must follow the
+ // regular PLT relocations and the TLSDESC relocations.
+ Reloc_section* irelative_rel_;
// The .got section.
Output_data_got<64, false>* got_;
// The .got.plt section.
Output_data_space* got_plt_;
+ // The part of the .got.plt section used for IRELATIVE relocs.
+ Output_data_space* got_irelative_;
// The number of PLT entries.
unsigned int count_;
+ // Number of PLT entries with R_X86_64_IRELATIVE relocs. These
+ // follow the regular PLT entries.
+ unsigned int irelative_count_;
// Offset of the reserved TLSDESC_GOT entry when needed.
unsigned int tlsdesc_got_offset_;
// List of available regions within the section, for incremental
// http://people.redhat.com/drepper/tls.pdf
// http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
-class Target_x86_64 : public Target_freebsd<64, false>
+class Target_x86_64 : public Sized_target<64, false>
{
public:
// In the x86_64 ABI (p 68), it says "The AMD64 ABI architectures
typedef Output_data_reloc<elfcpp::SHT_RELA, true, 64, false> Reloc_section;
Target_x86_64()
- : Target_freebsd<64, false>(&x86_64_info),
- got_(NULL), plt_(NULL), got_plt_(NULL), got_tlsdesc_(NULL),
- global_offset_table_(NULL), rela_dyn_(NULL),
- copy_relocs_(elfcpp::R_X86_64_COPY), dynbss_(NULL),
- got_mod_index_offset_(-1U), tlsdesc_reloc_info_(),
+ : Sized_target<64, false>(&x86_64_info),
+ got_(NULL), plt_(NULL), got_plt_(NULL), got_irelative_(NULL),
+ got_tlsdesc_(NULL), global_offset_table_(NULL), rela_dyn_(NULL),
+ rela_irelative_(NULL), copy_relocs_(elfcpp::R_X86_64_COPY),
+ dynbss_(NULL), got_mod_index_offset_(-1U), tlsdesc_reloc_info_(),
tls_base_symbol_defined_(false)
{ }
- // This function should be defined in targets that can use relocation
- // types to determine (implemented in local_reloc_may_be_function_pointer
- // and global_reloc_may_be_function_pointer)
- // if a function's pointer is taken. ICF uses this in safe mode to only
- // fold those functions whose pointer is defintely not taken. For x86_64
- // pie binaries, safe ICF cannot be done by looking at relocation types.
- inline bool
- can_check_for_function_pointers() const
- { return !parameters->options().pie(); }
-
- virtual bool
- can_icf_inline_merge_sections () const
- { return true; }
-
// Hook for a new output section.
void
do_new_output_section(Output_section*) const;
do_reloc_addend(void* arg, unsigned int r_type, uint64_t addend) const;
// Return the PLT section.
- Output_data*
- do_plt_section_for_global(const Symbol*) const
- { return this->plt_section(); }
+ uint64_t
+ do_plt_address_for_global(const Symbol* gsym) const
+ { return this->plt_section()->address_for_global(gsym); }
+
+ uint64_t
+ do_plt_address_for_local(const Relobj* relobj, unsigned int symndx) const
+ { return this->plt_section()->address_for_local(relobj, symndx); }
+
+ // This function should be defined in targets that can use relocation
+ // types to determine (implemented in local_reloc_may_be_function_pointer
+ // and global_reloc_may_be_function_pointer)
+ // if a function's pointer is taken. ICF uses this in safe mode to only
+ // fold those functions whose pointer is defintely not taken. For x86_64
+ // pie binaries, safe ICF cannot be done by looking at relocation types.
+ bool
+ do_can_check_for_function_pointers() const
+ { return !parameters->options().pie(); }
- Output_data*
- do_plt_section_for_local(const Relobj*, unsigned int) const
- { return this->plt_section(); }
+ // Return the base for a DW_EH_PE_datarel encoding.
+ uint64_t
+ do_ehframe_datarel_base() const;
// Adjust -fsplit-stack code which calls non-split-stack code.
void
// Register an existing PLT entry for a global symbol.
void
- register_global_plt_entry(unsigned int plt_index, Symbol* gsym);
+ register_global_plt_entry(Symbol_table*, Layout*, unsigned int plt_index,
+ Symbol* gsym);
// Force a COPY relocation for a given symbol.
void
Symbol*);
void
- check_non_pic(Relobj*, unsigned int r_type);
+ check_non_pic(Relobj*, unsigned int r_type, Symbol*);
inline bool
possible_function_pointer_reloc(unsigned int r_type);
Reloc_section*
rela_tlsdesc_section(Layout*) const;
+ // Get the section to use for IRELATIVE relocations.
+ Reloc_section*
+ rela_irelative_section(Layout*);
+
// Add a potential copy relocation.
void
copy_reloc(Symbol_table* symtab, Layout* layout,
Output_data_plt_x86_64* plt_;
// The GOT PLT section.
Output_data_space* got_plt_;
+ // The GOT section for IRELATIVE relocations.
+ Output_data_space* got_irelative_;
// The GOT section for TLSDESC relocations.
Output_data_got<64, false>* got_tlsdesc_;
// The _GLOBAL_OFFSET_TABLE_ symbol.
Symbol* global_offset_table_;
// The dynamic reloc section.
Reloc_section* rela_dyn_;
+ // The section to use for IRELATIVE relocs.
+ Reloc_section* rela_irelative_;
// Relocs saved to avoid a COPY reloc.
Copy_relocs<elfcpp::SHT_RELA, 64, false> copy_relocs_;
// Space for variables copied with a COPY reloc.
false, // has_resolve
true, // has_code_fill
true, // is_default_stack_executable
+ true, // can_icf_inline_merge_sections
'\0', // wrap_char
"/lib/ld64.so.1", // program interpreter
0x400000, // default_text_segment_address
{
gold_assert(symtab != NULL && layout != NULL);
+ // When using -z now, we can treat .got.plt as a relro section.
+ // Without -z now, it is modified after program startup by lazy
+ // PLT relocations.
+ bool is_got_plt_relro = parameters->options().now();
+ Output_section_order got_order = (is_got_plt_relro
+ ? ORDER_RELRO
+ : ORDER_RELRO_LAST);
+ Output_section_order got_plt_order = (is_got_plt_relro
+ ? ORDER_RELRO
+ : ORDER_NON_RELRO_FIRST);
+
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_, ORDER_RELRO_LAST,
- true);
+ this->got_, got_order, true);
this->got_plt_ = new Output_data_space(8, "** GOT PLT");
layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
(elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE),
- this->got_plt_, ORDER_NON_RELRO_FIRST,
- false);
+ this->got_plt_, got_plt_order,
+ is_got_plt_relro);
// The first three entries are reserved.
this->got_plt_->set_current_data_size(3 * 8);
- // Those bytes can go into the relro segment.
- layout->increase_relro(3 * 8);
+ if (!is_got_plt_relro)
+ {
+ // Those bytes can go into the relro segment.
+ layout->increase_relro(3 * 8);
+ }
// Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
this->global_offset_table_ =
elfcpp::STV_HIDDEN, 0,
false, false);
+ // If there are any IRELATIVE relocations, they get GOT entries
+ // in .got.plt after the jump slot entries.
+ this->got_irelative_ = new Output_data_space(8, "** GOT IRELATIVE PLT");
+ layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
+ (elfcpp::SHF_ALLOC
+ | elfcpp::SHF_WRITE),
+ this->got_irelative_,
+ got_plt_order, is_got_plt_relro);
+
// If there are any TLSDESC relocations, they get GOT entries in
- // .got.plt after the jump slot entries.
+ // .got.plt after the jump slot and IRELATIVE entries.
this->got_tlsdesc_ = new Output_data_got<64, false>();
layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
(elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE),
this->got_tlsdesc_,
- ORDER_NON_RELRO_FIRST, false);
+ got_plt_order, is_got_plt_relro);
}
return this->got_;
return this->rela_dyn_;
}
+// Get the section to use for IRELATIVE relocs, creating it if
+// necessary. These go in .rela.dyn, but only after all other dynamic
+// relocations. They need to follow the other dynamic relocations so
+// that they can refer to global variables initialized by those
+// relocs.
+
+Target_x86_64::Reloc_section*
+Target_x86_64::rela_irelative_section(Layout* layout)
+{
+ if (this->rela_irelative_ == NULL)
+ {
+ // Make sure we have already created the dynamic reloc section.
+ this->rela_dyn_section(layout);
+ this->rela_irelative_ = new Reloc_section(false);
+ layout->add_output_section_data(".rela.dyn", elfcpp::SHT_RELA,
+ elfcpp::SHF_ALLOC, this->rela_irelative_,
+ ORDER_DYNAMIC_RELOCS, false);
+ gold_assert(this->rela_dyn_->output_section()
+ == this->rela_irelative_->output_section());
+ }
+ return this->rela_irelative_;
+}
+
// Initialize the PLT section.
void
-Output_data_plt_x86_64::init(Symbol_table* symtab, Layout* layout)
+Output_data_plt_x86_64::init(Layout* layout)
{
this->rel_ = new Reloc_section(false);
layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
elfcpp::SHF_ALLOC, this->rel_,
ORDER_DYNAMIC_PLT_RELOCS, false);
- if (parameters->doing_static_link())
- {
- // A statically linked executable will only have a .rela.plt
- // section to hold R_X86_64_IRELATIVE relocs for STT_GNU_IFUNC
- // symbols. The library will use these symbols to locate the
- // IRELATIVE relocs at program startup time.
- symtab->define_in_output_data("__rela_iplt_start", NULL,
- Symbol_table::PREDEFINED,
- this->rel_, 0, 0, elfcpp::STT_NOTYPE,
- elfcpp::STB_GLOBAL, elfcpp::STV_HIDDEN,
- 0, false, true);
- symtab->define_in_output_data("__rela_iplt_end", NULL,
- Symbol_table::PREDEFINED,
- this->rel_, 0, 0, elfcpp::STT_NOTYPE,
- elfcpp::STB_GLOBAL, elfcpp::STV_HIDDEN,
- 0, true, true);
- }
+ // Add unwind information if requested.
+ if (parameters->options().ld_generated_unwind_info())
+ layout->add_eh_frame_for_plt(this, plt_eh_frame_cie, plt_eh_frame_cie_size,
+ plt_eh_frame_fde, plt_eh_frame_fde_size);
}
void
// Add an entry to the PLT.
void
-Output_data_plt_x86_64::add_entry(Symbol* gsym)
+Output_data_plt_x86_64::add_entry(Symbol_table* symtab, Layout* layout,
+ Symbol* gsym)
{
gold_assert(!gsym->has_plt_offset());
off_t plt_offset;
section_offset_type got_offset;
+ unsigned int* pcount;
+ unsigned int offset;
+ unsigned int reserved;
+ Output_data_space* got;
+ if (gsym->type() == elfcpp::STT_GNU_IFUNC
+ && gsym->can_use_relative_reloc(false))
+ {
+ pcount = &this->irelative_count_;
+ offset = 0;
+ reserved = 0;
+ got = this->got_irelative_;
+ }
+ else
+ {
+ pcount = &this->count_;
+ offset = 1;
+ reserved = 3;
+ got = this->got_plt_;
+ }
+
if (!this->is_data_size_valid())
{
- // Note that when setting the PLT offset we skip the initial
- // reserved PLT entry.
- plt_index = this->count_ + 1;
+ // Note that when setting the PLT offset for a non-IRELATIVE
+ // entry we skip the initial reserved PLT entry.
+ plt_index = *pcount + offset;
plt_offset = plt_index * plt_entry_size;
- ++this->count_;
+ ++*pcount;
- got_offset = (plt_index - 1 + 3) * 8;
- gold_assert(got_offset == this->got_plt_->current_data_size());
+ got_offset = (plt_index - offset + reserved) * 8;
+ gold_assert(got_offset == got->current_data_size());
// Every PLT entry needs a GOT entry which points back to the PLT
// entry (this will be changed by the dynamic linker, normally
// lazily when the function is called).
- this->got_plt_->set_current_data_size(got_offset + 8);
+ got->set_current_data_size(got_offset + 8);
}
else
{
+ // FIXME: This is probably not correct for IRELATIVE relocs.
+
// For incremental updates, find an available slot.
plt_offset = this->free_list_.allocate(plt_entry_size, plt_entry_size, 0);
if (plt_offset == -1)
// can be calculated from the PLT index, adjusting for the three
// reserved entries at the beginning of the GOT.
plt_index = plt_offset / plt_entry_size - 1;
- got_offset = (plt_index - 1 + 3) * 8;
+ got_offset = (plt_index - offset + reserved) * 8;
}
gsym->set_plt_offset(plt_offset);
// Every PLT entry needs a reloc.
- this->add_relocation(gsym, got_offset);
+ this->add_relocation(symtab, layout, gsym, got_offset);
// Note that we don't need to save the symbol. The contents of the
// PLT are independent of which symbols are used. The symbols only
unsigned int
Output_data_plt_x86_64::add_local_ifunc_entry(
+ Symbol_table* symtab,
+ Layout* layout,
Sized_relobj_file<64, false>* relobj,
unsigned int local_sym_index)
{
- unsigned int plt_offset = (this->count_ + 1) * plt_entry_size;
- ++this->count_;
+ unsigned int plt_offset = this->irelative_count_ * plt_entry_size;
+ ++this->irelative_count_;
- section_offset_type got_offset = this->got_plt_->current_data_size();
+ section_offset_type got_offset = this->got_irelative_->current_data_size();
// Every PLT entry needs a GOT entry which points back to the PLT
// entry.
- this->got_plt_->set_current_data_size(got_offset + 8);
+ this->got_irelative_->set_current_data_size(got_offset + 8);
// Every PLT entry needs a reloc.
- this->rel_->add_symbolless_local_addend(relobj, local_sym_index,
- elfcpp::R_X86_64_IRELATIVE,
- this->got_plt_, got_offset, 0);
+ Reloc_section* rela = this->rela_irelative(symtab, layout);
+ rela->add_symbolless_local_addend(relobj, local_sym_index,
+ elfcpp::R_X86_64_IRELATIVE,
+ this->got_irelative_, got_offset, 0);
return plt_offset;
}
// Add the relocation for a PLT entry.
void
-Output_data_plt_x86_64::add_relocation(Symbol* gsym, unsigned int got_offset)
+Output_data_plt_x86_64::add_relocation(Symbol_table* symtab, Layout* layout,
+ Symbol* gsym, unsigned int got_offset)
{
if (gsym->type() == elfcpp::STT_GNU_IFUNC
&& gsym->can_use_relative_reloc(false))
- this->rel_->add_symbolless_global_addend(gsym, elfcpp::R_X86_64_IRELATIVE,
- this->got_plt_, got_offset, 0);
+ {
+ Reloc_section* rela = this->rela_irelative(symtab, layout);
+ rela->add_symbolless_global_addend(gsym, elfcpp::R_X86_64_IRELATIVE,
+ this->got_irelative_, got_offset, 0);
+ }
else
{
gsym->set_needs_dynsym_entry();
layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
elfcpp::SHF_ALLOC, this->tlsdesc_rel_,
ORDER_DYNAMIC_PLT_RELOCS, false);
- gold_assert(this->tlsdesc_rel_->output_section() ==
- this->rel_->output_section());
+ gold_assert(this->tlsdesc_rel_->output_section()
+ == this->rel_->output_section());
}
return this->tlsdesc_rel_;
}
+// Return where the IRELATIVE relocations should go in the PLT. These
+// follow the JUMP_SLOT and the TLSDESC relocations.
+
+Output_data_plt_x86_64::Reloc_section*
+Output_data_plt_x86_64::rela_irelative(Symbol_table* symtab, Layout* layout)
+{
+ if (this->irelative_rel_ == NULL)
+ {
+ // Make sure we have a place for the TLSDESC relocations, in
+ // case we see any later on.
+ this->rela_tlsdesc(layout);
+ this->irelative_rel_ = new Reloc_section(false);
+ layout->add_output_section_data(".rela.plt", elfcpp::SHT_RELA,
+ elfcpp::SHF_ALLOC, this->irelative_rel_,
+ ORDER_DYNAMIC_PLT_RELOCS, false);
+ gold_assert(this->irelative_rel_->output_section()
+ == this->rel_->output_section());
+
+ if (parameters->doing_static_link())
+ {
+ // A statically linked executable will only have a .rela.plt
+ // section to hold R_X86_64_IRELATIVE relocs for
+ // STT_GNU_IFUNC symbols. The library will use these
+ // symbols to locate the IRELATIVE relocs at program startup
+ // time.
+ symtab->define_in_output_data("__rela_iplt_start", NULL,
+ Symbol_table::PREDEFINED,
+ this->irelative_rel_, 0, 0,
+ elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
+ elfcpp::STV_HIDDEN, 0, false, true);
+ symtab->define_in_output_data("__rela_iplt_end", NULL,
+ Symbol_table::PREDEFINED,
+ this->irelative_rel_, 0, 0,
+ elfcpp::STT_NOTYPE, elfcpp::STB_GLOBAL,
+ elfcpp::STV_HIDDEN, 0, true, true);
+ }
+ }
+ return this->irelative_rel_;
+}
+
+// Return the PLT address to use for a global symbol.
+
+uint64_t
+Output_data_plt_x86_64::address_for_global(const Symbol* gsym)
+{
+ uint64_t offset = 0;
+ if (gsym->type() == elfcpp::STT_GNU_IFUNC
+ && gsym->can_use_relative_reloc(false))
+ offset = (this->count_ + 1) * plt_entry_size;
+ return this->address() + offset;
+}
+
+// Return the PLT address to use for a local symbol. These are always
+// IRELATIVE relocs.
+
+uint64_t
+Output_data_plt_x86_64::address_for_local(const Relobj*, unsigned int)
+{
+ return this->address() + (this->count_ + 1) * plt_entry_size;
+}
+
// Set the final size.
void
Output_data_plt_x86_64::set_final_data_size()
{
- unsigned int count = this->count_;
+ unsigned int count = this->count_ + this->irelative_count_;
if (this->has_tlsdesc_entry())
++count;
this->set_data_size((count + 1) * plt_entry_size);
// The first entry in the PLT for an executable.
-unsigned char Output_data_plt_x86_64::first_plt_entry[plt_entry_size] =
+const unsigned char Output_data_plt_x86_64::first_plt_entry[plt_entry_size] =
{
// From AMD64 ABI Draft 0.98, page 76
0xff, 0x35, // pushq contents of memory address
// Subsequent entries in the PLT for an executable.
-unsigned char Output_data_plt_x86_64::plt_entry[plt_entry_size] =
+const unsigned char Output_data_plt_x86_64::plt_entry[plt_entry_size] =
{
// From AMD64 ABI Draft 0.98, page 76
0xff, 0x25, // jmpq indirect
// The reserved TLSDESC entry in the PLT for an executable.
-unsigned char Output_data_plt_x86_64::tlsdesc_plt_entry[plt_entry_size] =
+const unsigned char Output_data_plt_x86_64::tlsdesc_plt_entry[plt_entry_size] =
{
// From Alexandre Oliva, "Thread-Local Storage Descriptors for IA32
// and AMD64/EM64T", Version 0.9.4 (2005-10-10).
0x40, 0
};
+// The .eh_frame unwind information for the PLT.
+
+const unsigned char
+Output_data_plt_x86_64::plt_eh_frame_cie[plt_eh_frame_cie_size] =
+{
+ 1, // CIE version.
+ 'z', // Augmentation: augmentation size included.
+ 'R', // Augmentation: FDE encoding included.
+ '\0', // End of augmentation string.
+ 1, // Code alignment factor.
+ 0x78, // Data alignment factor.
+ 16, // Return address column.
+ 1, // Augmentation size.
+ (elfcpp::DW_EH_PE_pcrel // FDE encoding.
+ | elfcpp::DW_EH_PE_sdata4),
+ elfcpp::DW_CFA_def_cfa, 7, 8, // DW_CFA_def_cfa: r7 (rsp) ofs 8.
+ elfcpp::DW_CFA_offset + 16, 1,// DW_CFA_offset: r16 (rip) at cfa-8.
+ elfcpp::DW_CFA_nop, // Align to 16 bytes.
+ elfcpp::DW_CFA_nop
+};
+
+const unsigned char
+Output_data_plt_x86_64::plt_eh_frame_fde[plt_eh_frame_fde_size] =
+{
+ 0, 0, 0, 0, // Replaced with offset to .plt.
+ 0, 0, 0, 0, // Replaced with size of .plt.
+ 0, // Augmentation size.
+ elfcpp::DW_CFA_def_cfa_offset, 16, // DW_CFA_def_cfa_offset: 16.
+ elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6.
+ elfcpp::DW_CFA_def_cfa_offset, 24, // DW_CFA_def_cfa_offset: 24.
+ elfcpp::DW_CFA_advance_loc + 10, // Advance 10 to __PLT__ + 16.
+ elfcpp::DW_CFA_def_cfa_expression, // DW_CFA_def_cfa_expression.
+ 11, // Block length.
+ elfcpp::DW_OP_breg7, 8, // Push %rsp + 8.
+ elfcpp::DW_OP_breg16, 0, // Push %rip.
+ elfcpp::DW_OP_lit15, // Push 0xf.
+ elfcpp::DW_OP_and, // & (%rip & 0xf).
+ elfcpp::DW_OP_lit11, // Push 0xb.
+ elfcpp::DW_OP_ge, // >= ((%rip & 0xf) >= 0xb)
+ elfcpp::DW_OP_lit3, // Push 3.
+ elfcpp::DW_OP_shl, // << (((%rip & 0xf) >= 0xb) << 3)
+ elfcpp::DW_OP_plus, // + ((((%rip&0xf)>=0xb)<<3)+%rsp+8
+ elfcpp::DW_CFA_nop, // Align to 32 bytes.
+ elfcpp::DW_CFA_nop,
+ elfcpp::DW_CFA_nop,
+ elfcpp::DW_CFA_nop
+};
+
// Write out the PLT. This uses the hand-coded instructions above,
// and adjusts them as needed. This is specified by the AMD64 ABI.
unsigned char* const oview = of->get_output_view(offset, oview_size);
const off_t got_file_offset = this->got_plt_->offset();
+ gold_assert(parameters->incremental_update()
+ || (got_file_offset + this->got_plt_->data_size()
+ == this->got_irelative_->offset()));
const section_size_type got_size =
- convert_to_section_size_type(this->got_plt_->data_size());
+ convert_to_section_size_type(this->got_plt_->data_size()
+ + this->got_irelative_->data_size());
unsigned char* const got_view = of->get_output_view(got_file_offset,
got_size);
unsigned char* got_pov = got_view;
- memset(got_pov, 0, 24);
- got_pov += 24;
+ // The first entry in the GOT is the address of the .dynamic section
+ // aka the PT_DYNAMIC segment. The next two entries are reserved.
+ // We saved space for them when we created the section in
+ // Target_x86_64::got_section.
+ Output_section* dynamic = this->layout_->dynamic_section();
+ uint32_t dynamic_addr = dynamic == NULL ? 0 : dynamic->address();
+ elfcpp::Swap<64, false>::writeval(got_pov, dynamic_addr);
+ got_pov += 8;
+ memset(got_pov, 0, 16);
+ got_pov += 16;
unsigned int plt_offset = plt_entry_size;
unsigned int got_offset = 24;
- const unsigned int count = this->count_;
+ const unsigned int count = this->count_ + this->irelative_count_;
for (unsigned int plt_index = 0;
plt_index < count;
++plt_index,
// Create the GOT sections first.
this->got_section(symtab, layout);
- this->plt_ = new Output_data_plt_x86_64(symtab, layout, this->got_,
- this->got_plt_);
+ this->plt_ = new Output_data_plt_x86_64(layout, this->got_,
+ this->got_plt_,
+ this->got_irelative_);
layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
(elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR),
if (this->plt_ == NULL)
this->make_plt_section(symtab, layout);
- this->plt_->add_entry(gsym);
+ this->plt_->add_entry(symtab, layout, gsym);
}
// Make a PLT entry for a local STT_GNU_IFUNC symbol.
return;
if (this->plt_ == NULL)
this->make_plt_section(symtab, layout);
- unsigned int plt_offset = this->plt_->add_local_ifunc_entry(relobj,
+ unsigned int plt_offset = this->plt_->add_local_ifunc_entry(symtab, layout,
+ relobj,
local_sym_index);
relobj->set_local_plt_offset(local_sym_index, plt_offset);
}
this->got_tlsdesc_,
ORDER_NON_RELRO_FIRST, false);
+ // If there are any IRELATIVE relocations, they get GOT entries in
+ // .got.plt after the jump slot and TLSDESC entries.
+ this->got_irelative_ = new Output_data_space(0, 8, "** GOT IRELATIVE PLT");
+ layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
+ elfcpp::SHF_ALLOC | elfcpp::SHF_WRITE,
+ this->got_irelative_,
+ ORDER_NON_RELRO_FIRST, false);
+
// Create the PLT section.
- this->plt_ = new Output_data_plt_x86_64(symtab, layout, this->got_,
- this->got_plt_, plt_count);
+ this->plt_ = new Output_data_plt_x86_64(layout, this->got_, this->got_plt_,
+ this->got_irelative_, plt_count);
layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
elfcpp::SHF_ALLOC | elfcpp::SHF_EXECINSTR,
this->plt_, ORDER_PLT, false);
case GOT_TYPE_STANDARD:
if (parameters->options().output_is_position_independent())
rela_dyn->add_local_relative(obj, r_sym, elfcpp::R_X86_64_RELATIVE,
- this->got_, got_offset, 0);
+ this->got_, got_offset, 0, false);
break;
case GOT_TYPE_TLS_OFFSET:
rela_dyn->add_local(obj, r_sym, elfcpp::R_X86_64_TPOFF64,
// Register an existing PLT entry for a global symbol.
void
-Target_x86_64::register_global_plt_entry(unsigned int plt_index,
+Target_x86_64::register_global_plt_entry(Symbol_table* symtab,
+ Layout* layout,
+ unsigned int plt_index,
Symbol* gsym)
{
gold_assert(this->plt_ != NULL);
gsym->set_plt_offset((plt_index + 1) * this->plt_entry_size());
unsigned int got_offset = (plt_index + 3) * 8;
- this->plt_->add_relocation(gsym, got_offset);
+ this->plt_->add_relocation(symtab, layout, gsym, got_offset);
}
// Force a COPY relocation for a given symbol.
// Here we know the section is allocated, but we don't know that it is
// read-only. But we check for all the relocation types which the
// glibc dynamic linker supports, so it seems appropriate to issue an
-// error even if the section is not read-only.
+// error even if the section is not read-only. If GSYM is not NULL,
+// it is the symbol the relocation is against; if it is NULL, the
+// relocation is against a local symbol.
void
-Target_x86_64::Scan::check_non_pic(Relobj* object, unsigned int r_type)
+Target_x86_64::Scan::check_non_pic(Relobj* object, unsigned int r_type,
+ Symbol* gsym)
{
switch (r_type)
{
return;
// glibc supports these reloc types, but they can overflow.
- case elfcpp::R_X86_64_32:
case elfcpp::R_X86_64_PC32:
+ // A PC relative reference is OK against a local symbol or if
+ // the symbol is defined locally.
+ if (gsym == NULL
+ || (!gsym->is_from_dynobj()
+ && !gsym->is_undefined()
+ && !gsym->is_preemptible()))
+ return;
+ /* Fall through. */
+ case elfcpp::R_X86_64_32:
if (this->issued_non_pic_error_)
return;
gold_assert(parameters->options().output_is_position_independent());
- object->error(_("requires dynamic reloc which may overflow at runtime; "
- "recompile with -fPIC"));
+ if (gsym == NULL)
+ object->error(_("requires dynamic R_X86_64_32 reloc which may "
+ "overflow at runtime; recompile with -fPIC"));
+ else
+ object->error(_("requires dynamic %s reloc against '%s' which may "
+ "overflow at runtime; recompile with -fPIC"),
+ (r_type == elfcpp::R_X86_64_32
+ ? "R_X86_64_32"
+ : "R_X86_64_PC32"),
+ gsym->name());
this->issued_non_pic_error_ = true;
return;
if (this->issued_non_pic_error_)
return;
gold_assert(parameters->options().output_is_position_independent());
- object->error(_("requires unsupported dynamic reloc; "
- "recompile with -fPIC"));
+ object->error(_("requires unsupported dynamic reloc %u; "
+ "recompile with -fPIC"),
+ r_type);
this->issued_non_pic_error_ = true;
return;
const elfcpp::Sym<64, false>& lsym)
{
// A local STT_GNU_IFUNC symbol may require a PLT entry.
- if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC
- && this->reloc_needs_plt_for_ifunc(object, r_type))
+ bool is_ifunc = lsym.get_st_type() == elfcpp::STT_GNU_IFUNC;
+ if (is_ifunc && this->reloc_needs_plt_for_ifunc(object, r_type))
{
unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym);
elfcpp::R_X86_64_RELATIVE,
output_section, data_shndx,
reloc.get_r_offset(),
- reloc.get_r_addend());
+ reloc.get_r_addend(), is_ifunc);
}
break;
// because that is always a 64-bit relocation.
if (parameters->options().output_is_position_independent())
{
- this->check_non_pic(object, r_type);
+ this->check_non_pic(object, r_type, NULL);
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
unsigned int r_sym = elfcpp::elf_r_sym<64>(reloc.get_r_info());
// lets function pointers compare correctly with shared
// libraries. Otherwise we would need an IRELATIVE reloc.
bool is_new;
- if (lsym.get_st_type() == elfcpp::STT_GNU_IFUNC)
+ if (is_ifunc)
is_new = got->add_local_plt(object, r_sym, GOT_TYPE_STANDARD);
else
is_new = got->add_local(object, r_sym, GOT_TYPE_STANDARD);
object->local_got_offset(r_sym, GOT_TYPE_STANDARD);
rela_dyn->add_local_relative(object, r_sym,
elfcpp::R_X86_64_RELATIVE,
- got, got_offset, 0);
+ got, got_offset, 0, is_ifunc);
}
else
{
- this->check_non_pic(object, r_type);
+ this->check_non_pic(object, r_type, NULL);
gold_assert(lsym.get_st_type() != elfcpp::STT_SECTION);
rela_dyn->add_local(
// STT_GNU_IFUNC symbol. This makes a function
// address in a PIE executable match the address in a
// shared library that it links against.
- Reloc_section* rela_dyn = target->rela_dyn_section(layout);
+ Reloc_section* rela_dyn =
+ target->rela_irelative_section(layout);
unsigned int r_type = elfcpp::R_X86_64_IRELATIVE;
rela_dyn->add_symbolless_global_addend(gsym, r_type,
output_section, object,
}
else
{
- this->check_non_pic(object, r_type);
+ this->check_non_pic(object, r_type, gsym);
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
rela_dyn->add_global(gsym, r_type, output_section, object,
data_shndx, reloc.get_r_offset(),
}
else
{
- this->check_non_pic(object, r_type);
+ this->check_non_pic(object, r_type, gsym);
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
rela_dyn->add_global(gsym, r_type, output_section, object,
data_shndx, reloc.get_r_offset(),
// If this symbol is not fully resolved, we need to add a
// dynamic relocation for it.
Reloc_section* rela_dyn = target->rela_dyn_section(layout);
+
+ // Use a GLOB_DAT rather than a RELATIVE reloc if:
+ //
+ // 1) The symbol may be defined in some other module.
+ //
+ // 2) We are building a shared library and this is a
+ // protected symbol; using GLOB_DAT means that the dynamic
+ // linker can use the address of the PLT in the main
+ // executable when appropriate so that function address
+ // comparisons work.
+ //
+ // 3) This is a STT_GNU_IFUNC symbol in position dependent
+ // code, again so that function address comparisons work.
if (gsym->is_from_dynobj()
|| gsym->is_undefined()
|| gsym->is_preemptible()
+ || (gsym->visibility() == elfcpp::STV_PROTECTED
+ && parameters->options().shared())
|| (gsym->type() == elfcpp::STT_GNU_IFUNC
&& parameters->options().output_is_position_independent()))
got->add_global_with_rela(gsym, GOT_TYPE_STANDARD, rela_dyn,
uint64_t data_size = this->got_plt_->current_data_size();
symtab->get_sized_symbol<64>(sym)->set_symsize(data_size);
}
+
+ if (parameters->doing_static_link()
+ && (this->plt_ == NULL || !this->plt_->has_irelative_section()))
+ {
+ // If linking statically, make sure that the __rela_iplt symbols
+ // were defined if necessary, even if we didn't create a PLT.
+ static const Define_symbol_in_segment syms[] =
+ {
+ {
+ "__rela_iplt_start", // name
+ elfcpp::PT_LOAD, // segment_type
+ elfcpp::PF_W, // segment_flags_set
+ elfcpp::PF(0), // segment_flags_clear
+ 0, // value
+ 0, // size
+ elfcpp::STT_NOTYPE, // type
+ elfcpp::STB_GLOBAL, // binding
+ elfcpp::STV_HIDDEN, // visibility
+ 0, // nonvis
+ Symbol::SEGMENT_START, // offset_from_base
+ true // only_if_ref
+ },
+ {
+ "__rela_iplt_end", // name
+ elfcpp::PT_LOAD, // segment_type
+ elfcpp::PF_W, // segment_flags_set
+ elfcpp::PF(0), // segment_flags_clear
+ 0, // value
+ 0, // size
+ elfcpp::STT_NOTYPE, // type
+ elfcpp::STB_GLOBAL, // binding
+ elfcpp::STV_HIDDEN, // visibility
+ 0, // nonvis
+ Symbol::SEGMENT_START, // offset_from_base
+ true // only_if_ref
+ }
+ };
+
+ symtab->define_symbols(layout, 2, syms,
+ layout->script_options()->saw_sections_clause());
+ }
}
// Perform a relocation.
if (gsym != NULL
&& gsym->use_plt_offset(Scan::get_reference_flags(r_type)))
{
- symval.set_output_value(target->plt_section()->address()
+ symval.set_output_value(target->plt_address_for_global(gsym)
+ gsym->plt_offset());
psymval = &symval;
}
unsigned int r_sym = elfcpp::elf_r_sym<64>(rela.get_r_info());
if (object->local_has_plt_offset(r_sym))
{
- symval.set_output_value(target->plt_section()->address()
+ symval.set_output_value(target->plt_address_for_local(object, r_sym)
+ object->local_plt_offset(r_sym));
psymval = &symval;
}
}
if (optimized_type == tls::TLSOPT_TO_LE)
{
- gold_assert(tls_segment != NULL);
+ if (tls_segment == NULL)
+ {
+ gold_assert(parameters->errors()->error_count() > 0
+ || issue_undefined_symbol_error(gsym));
+ return;
+ }
this->tls_gd_to_le(relinfo, relnum, tls_segment,
rela, r_type, value, view,
view_size);
}
if (optimized_type == tls::TLSOPT_TO_IE)
{
- gold_assert(tls_segment != NULL);
+ if (tls_segment == NULL)
+ {
+ gold_assert(parameters->errors()->error_count() > 0
+ || issue_undefined_symbol_error(gsym));
+ return;
+ }
value = target->got_plt_section()->address() + got_offset;
this->tls_gd_to_ie(relinfo, relnum, tls_segment, rela, r_type,
value, view, address, view_size);
}
if (optimized_type == tls::TLSOPT_TO_LE)
{
- gold_assert(tls_segment != NULL);
+ if (tls_segment == NULL)
+ {
+ gold_assert(parameters->errors()->error_count() > 0
+ || issue_undefined_symbol_error(gsym));
+ return;
+ }
this->tls_desc_gd_to_le(relinfo, relnum, tls_segment,
rela, r_type, value, view,
view_size);
}
if (optimized_type == tls::TLSOPT_TO_IE)
{
- gold_assert(tls_segment != NULL);
+ if (tls_segment == NULL)
+ {
+ gold_assert(parameters->errors()->error_count() > 0
+ || issue_undefined_symbol_error(gsym));
+ return;
+ }
value = target->got_plt_section()->address() + got_offset;
this->tls_desc_gd_to_ie(relinfo, relnum, tls_segment,
rela, r_type, value, view, address,
}
if (optimized_type == tls::TLSOPT_TO_LE)
{
- gold_assert(tls_segment != NULL);
+ if (tls_segment == NULL)
+ {
+ gold_assert(parameters->errors()->error_count() > 0
+ || issue_undefined_symbol_error(gsym));
+ return;
+ }
this->tls_ld_to_le(relinfo, relnum, tls_segment, rela, r_type,
value, view, view_size);
break;
// R_X86_64_TLSLD.
if (optimized_type == tls::TLSOPT_TO_LE && is_executable)
{
- gold_assert(tls_segment != NULL);
+ if (tls_segment == NULL)
+ {
+ gold_assert(parameters->errors()->error_count() > 0
+ || issue_undefined_symbol_error(gsym));
+ return;
+ }
value -= tls_segment->memsz();
}
Relocate_functions<64, false>::rela32(view, value, addend);
// See R_X86_64_DTPOFF32, just above, for why we check for is_executable.
if (optimized_type == tls::TLSOPT_TO_LE && is_executable)
{
- gold_assert(tls_segment != NULL);
+ if (tls_segment == NULL)
+ {
+ gold_assert(parameters->errors()->error_count() > 0
+ || issue_undefined_symbol_error(gsym));
+ return;
+ }
value -= tls_segment->memsz();
}
Relocate_functions<64, false>::rela64(view, value, addend);
case elfcpp::R_X86_64_GOTTPOFF: // Initial-exec
if (optimized_type == tls::TLSOPT_TO_LE)
{
- gold_assert(tls_segment != NULL);
+ if (tls_segment == NULL)
+ {
+ gold_assert(parameters->errors()->error_count() > 0
+ || issue_undefined_symbol_error(gsym));
+ return;
+ }
Target_x86_64::Relocate::tls_ie_to_le(relinfo, relnum, tls_segment,
rela, r_type, value, view,
view_size);
break;
case elfcpp::R_X86_64_TPOFF32: // Local-exec
+ if (tls_segment == NULL)
+ {
+ gold_assert(parameters->errors()->error_count() > 0
+ || issue_undefined_symbol_error(gsym));
+ return;
+ }
value -= tls_segment->memsz();
Relocate_functions<64, false>::rela32(view, value, addend);
break;
Target_x86_64::do_dynsym_value(const Symbol* gsym) const
{
gold_assert(gsym->is_from_dynobj() && gsym->has_plt_offset());
- return this->plt_section()->address() + gsym->plt_offset();
+ return this->plt_address_for_global(gsym) + gsym->plt_offset();
}
// Return a string used to fill a code section with nops to take up
return psymval->value(ti.object, 0);
}
+// Return the value to use for the base of a DW_EH_PE_datarel offset
+// in an FDE. Solaris and SVR4 use DW_EH_PE_datarel because their
+// assembler can not write out the difference between two labels in
+// different sections, so instead of using a pc-relative value they
+// use an offset from the GOT.
+
+uint64_t
+Target_x86_64::do_ehframe_datarel_base() const
+{
+ gold_assert(this->global_offset_table_ != NULL);
+ Symbol* sym = this->global_offset_table_;
+ Sized_symbol<64>* ssym = static_cast<Sized_symbol<64>*>(sym);
+ return ssym->value();
+}
+
// FNOFFSET in section SHNDX in OBJECT is the start of a function
// compiled with -fsplit-stack. The function calls non-split-stack
// code. We have to change the function so that it always ensures
public:
Target_selector_x86_64()
: Target_selector_freebsd(elfcpp::EM_X86_64, 64, false, "elf64-x86-64",
- "elf64-x86-64-freebsd")
+ "elf64-x86-64-freebsd", "elf_x86_64")
{ }
Target*
projects / deliverable / binutils-gdb.git / blobdiff