// i386.cc -- i386 target support for gold.
-// Copyright 2006, 2007, 2008, 2009 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 "i386.h"
#include "target-select.h"
#include "tls.h"
#include "freebsd.h"
+#include "gc.h"
namespace
{
using namespace gold;
-class Output_data_plt_i386;
+// A class to handle the PLT data.
+
+class Output_data_plt_i386 : public Output_section_data
+{
+ public:
+ typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
+
+ Output_data_plt_i386(Symbol_table*, Layout*, Output_data_space*);
+
+ // Add an entry to the PLT.
+ void
+ add_entry(Symbol* gsym);
+
+ // Add an entry to the PLT for a local STT_GNU_IFUNC symbol.
+ unsigned int
+ add_local_ifunc_entry(Sized_relobj_file<32, false>* relobj,
+ unsigned int local_sym_index);
+
+ // Return the .rel.plt section data.
+ Reloc_section*
+ rel_plt() const
+ { return this->rel_; }
+
+ // Return where the TLS_DESC relocations should go.
+ Reloc_section*
+ rel_tls_desc(Layout*);
+
+ // Return the number of PLT entries.
+ unsigned int
+ entry_count() const
+ { return this->count_; }
+
+ // Return the offset of the first non-reserved PLT entry.
+ static unsigned int
+ first_plt_entry_offset()
+ { return plt_entry_size; }
+
+ // Return the size of a PLT entry.
+ static unsigned int
+ get_plt_entry_size()
+ { return plt_entry_size; }
+
+ protected:
+ 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;
+
+ // The first entry in the PLT for an executable.
+ static const unsigned char exec_first_plt_entry[plt_entry_size];
+
+ // The first entry in the PLT for a shared object.
+ static const unsigned char dyn_first_plt_entry[plt_entry_size];
+
+ // Other entries in the PLT for an executable.
+ static const unsigned char exec_plt_entry[plt_entry_size];
+
+ // Other entries in the PLT for a shared object.
+ static const unsigned char dyn_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
+ set_final_data_size()
+ { this->set_data_size((this->count_ + 1) * plt_entry_size); }
+
+ // Write out the PLT data.
+ void
+ do_write(Output_file*);
+
+ // We keep a list of global STT_GNU_IFUNC symbols, each with its
+ // offset in the GOT.
+ struct Global_ifunc
+ {
+ Symbol* sym;
+ unsigned int got_offset;
+ };
+
+ // We keep a list of local STT_GNU_IFUNC symbols, each with its
+ // offset in the GOT.
+ struct Local_ifunc
+ {
+ Sized_relobj_file<32, false>* object;
+ unsigned int local_sym_index;
+ unsigned int got_offset;
+ };
+
+ // The reloc section.
+ Reloc_section* rel_;
+ // The TLS_DESC relocations, if necessary. These must follow the
+ // regular PLT relocs.
+ Reloc_section* tls_desc_rel_;
+ // The .got.plt section.
+ Output_data_space* got_plt_;
+ // The number of PLT entries.
+ unsigned int count_;
+ // Global STT_GNU_IFUNC symbols.
+ std::vector<Global_ifunc> global_ifuncs_;
+ // Local STT_GNU_IFUNC symbols.
+ std::vector<Local_ifunc> local_ifuncs_;
+};
// The i386 target class.
// TLS info comes from
// http://people.redhat.com/drepper/tls.pdf
// http://www.lsd.ic.unicamp.br/~oliva/writeups/TLS/RFC-TLSDESC-x86.txt
-class Target_i386 : public Target_freebsd<32, false>
+class Target_i386 : public Sized_target<32, false>
{
public:
typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
Target_i386()
- : Target_freebsd<32, false>(&i386_info),
- got_(NULL), plt_(NULL), got_plt_(NULL), rel_dyn_(NULL),
+ : Sized_target<32, false>(&i386_info),
+ got_(NULL), plt_(NULL), got_plt_(NULL), got_tlsdesc_(NULL),
+ global_offset_table_(NULL), rel_dyn_(NULL),
copy_relocs_(elfcpp::R_386_COPY), dynbss_(NULL),
got_mod_index_offset_(-1U), tls_base_symbol_defined_(false)
{ }
// Process the relocations to determine unreferenced sections for
// garbage collection.
void
- gc_process_relocs(const General_options& options,
- Symbol_table* symtab,
+ gc_process_relocs(Symbol_table* symtab,
Layout* layout,
- Sized_relobj<32, false>* object,
+ Sized_relobj_file<32, false>* object,
unsigned int data_shndx,
unsigned int sh_type,
const unsigned char* prelocs,
// Scan the relocations to look for symbol adjustments.
void
- scan_relocs(const General_options& options,
- Symbol_table* symtab,
+ scan_relocs(Symbol_table* symtab,
Layout* layout,
- Sized_relobj<32, false>* object,
+ Sized_relobj_file<32, false>* object,
unsigned int data_shndx,
unsigned int sh_type,
const unsigned char* prelocs,
// Finalize the sections.
void
- do_finalize_sections(Layout*);
+ do_finalize_sections(Layout*, const Input_objects*, Symbol_table*);
// Return the value to use for a dynamic which requires special
// treatment.
bool needs_special_offset_handling,
unsigned char* view,
elfcpp::Elf_types<32>::Elf_Addr view_address,
- section_size_type view_size);
+ section_size_type view_size,
+ const Reloc_symbol_changes*);
// Scan the relocs during a relocatable link.
void
- scan_relocatable_relocs(const General_options& options,
- Symbol_table* symtab,
+ scan_relocatable_relocs(Symbol_table* symtab,
Layout* layout,
- Sized_relobj<32, false>* object,
+ Sized_relobj_file<32, false>* object,
unsigned int data_shndx,
unsigned int sh_type,
const unsigned char* prelocs,
do_is_defined_by_abi(const Symbol* sym) const
{ return strcmp(sym->name(), "___tls_get_addr") == 0; }
+ // Return whether a symbol name implies a local label. The UnixWare
+ // 2.1 cc generates temporary symbols that start with .X, so we
+ // recognize them here. FIXME: do other SVR4 compilers also use .X?.
+ // If so, we should move the .X recognition into
+ // Target::do_is_local_label_name.
+ bool
+ do_is_local_label_name(const char* name) const
+ {
+ if (name[0] == '.' && name[1] == 'X')
+ return true;
+ return Target::do_is_local_label_name(name);
+ }
+
+ // Return the PLT section.
+ Output_data*
+ do_plt_section_for_global(const Symbol*) const
+ { return this->plt_section(); }
+
+ Output_data*
+ do_plt_section_for_local(const Relobj*, unsigned int) const
+ { return this->plt_section(); }
+
+ // We can tell whether we take the address of a function.
+ inline bool
+ do_can_check_for_function_pointers() const
+ { return true; }
+
+ // Return whether SYM is call to a non-split function.
+ bool
+ do_is_call_to_non_split(const Symbol* sym, unsigned int) const;
+
+ // Adjust -fsplit-stack code which calls non-split-stack code.
+ void
+ do_calls_non_split(Relobj* object, unsigned int shndx,
+ section_offset_type fnoffset, section_size_type fnsize,
+ unsigned char* view, section_size_type view_size,
+ std::string* from, std::string* to) const;
+
// Return the size of the GOT section.
section_size_type
- got_size()
+ got_size() const
{
gold_assert(this->got_ != NULL);
return this->got_->data_size();
}
+ // Return the number of entries in the GOT.
+ unsigned int
+ got_entry_count() const
+ {
+ if (this->got_ == NULL)
+ return 0;
+ return this->got_size() / 4;
+ }
+
+ // Return the number of entries in the PLT.
+ unsigned int
+ plt_entry_count() const;
+
+ // Return the offset of the first non-reserved PLT entry.
+ unsigned int
+ first_plt_entry_offset() const;
+
+ // Return the size of each PLT entry.
+ unsigned int
+ plt_entry_size() const;
+
private:
// The class which scans relocations.
struct Scan
{
+ static inline int
+
+ get_reference_flags(unsigned int r_type);
+
inline void
- local(const General_options& options, Symbol_table* symtab,
- Layout* layout, Target_i386* target,
- Sized_relobj<32, false>* object,
+ local(Symbol_table* symtab, Layout* layout, Target_i386* target,
+ Sized_relobj_file<32, false>* object,
unsigned int data_shndx,
Output_section* output_section,
const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
const elfcpp::Sym<32, false>& lsym);
inline void
- global(const General_options& options, Symbol_table* symtab,
- Layout* layout, Target_i386* target,
- Sized_relobj<32, false>* object,
+ global(Symbol_table* symtab, Layout* layout, Target_i386* target,
+ Sized_relobj_file<32, false>* object,
unsigned int data_shndx,
Output_section* output_section,
const elfcpp::Rel<32, false>& reloc, unsigned int r_type,
Symbol* gsym);
+ inline bool
+ local_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
+ Target_i386* target,
+ Sized_relobj_file<32, false>* object,
+ unsigned int data_shndx,
+ Output_section* output_section,
+ const elfcpp::Rel<32, false>& reloc,
+ unsigned int r_type,
+ const elfcpp::Sym<32, false>& lsym);
+
+ inline bool
+ global_reloc_may_be_function_pointer(Symbol_table* symtab, Layout* layout,
+ Target_i386* target,
+ Sized_relobj_file<32, false>* object,
+ unsigned int data_shndx,
+ Output_section* output_section,
+ const elfcpp::Rel<32, false>& reloc,
+ unsigned int r_type,
+ Symbol* gsym);
+
+ inline bool
+ possible_function_pointer_reloc(unsigned int r_type);
+
+ bool
+ reloc_needs_plt_for_ifunc(Sized_relobj_file<32, false>*,
+ unsigned int r_type);
+
static void
- unsupported_reloc_local(Sized_relobj<32, false>*, unsigned int r_type);
+ unsupported_reloc_local(Sized_relobj_file<32, false>*, unsigned int r_type);
static void
- unsupported_reloc_global(Sized_relobj<32, false>*, unsigned int r_type,
+ unsupported_reloc_global(Sized_relobj_file<32, false>*, unsigned int r_type,
Symbol*);
};
// Return whether the static relocation needs to be applied.
inline bool
should_apply_static_reloc(const Sized_symbol<32>* gsym,
- int ref_flags,
+ unsigned int r_type,
bool is_32bit,
Output_section* output_section);
return this->got_plt_;
}
+ // Get the GOT section for TLSDESC entries.
+ Output_data_got<32, false>*
+ got_tlsdesc_section() const
+ {
+ gold_assert(this->got_tlsdesc_ != NULL);
+ return this->got_tlsdesc_;
+ }
+
+ // Create the PLT section.
+ void
+ make_plt_section(Symbol_table* symtab, Layout* layout);
+
// Create a PLT entry for a global symbol.
void
make_plt_entry(Symbol_table*, Layout*, Symbol*);
+ // Create a PLT entry for a local STT_GNU_IFUNC symbol.
+ void
+ make_local_ifunc_plt_entry(Symbol_table*, Layout*,
+ Sized_relobj_file<32, false>* relobj,
+ unsigned int local_sym_index);
+
// Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
void
define_tls_base_symbol(Symbol_table*, Layout*);
// Create a GOT entry for the TLS module index.
unsigned int
got_mod_index_entry(Symbol_table* symtab, Layout* layout,
- Sized_relobj<32, false>* object);
+ Sized_relobj_file<32, false>* object);
// Get the PLT section.
- const Output_data_plt_i386*
+ Output_data_plt_i386*
plt_section() const
{
gold_assert(this->plt_ != NULL);
Reloc_section*
rel_dyn_section(Layout*);
- // Return true if the symbol may need a COPY relocation.
- // References from an executable object to non-function symbols
- // defined in a dynamic object may need a COPY relocation.
- bool
- may_need_copy_reloc(Symbol* gsym)
- {
- return (!parameters->options().shared()
- && gsym->is_from_dynobj()
- && gsym->type() != elfcpp::STT_FUNC);
- }
+ // Get the section to use for TLS_DESC relocations.
+ Reloc_section*
+ rel_tls_desc_section(Layout*) const;
// Add a potential copy relocation.
void
copy_reloc(Symbol_table* symtab, Layout* layout,
- Sized_relobj<32, false>* object,
+ Sized_relobj_file<32, false>* object,
unsigned int shndx, Output_section* output_section,
Symbol* sym, const elfcpp::Rel<32, false>& reloc)
{
static const Target::Target_info i386_info;
// The types of GOT entries needed for this platform.
+ // These values are exposed to the ABI in an incremental link.
+ // Do not renumber existing values without changing the version
+ // number of the .gnu_incremental_inputs section.
enum Got_type
{
GOT_TYPE_STANDARD = 0, // GOT entry for a regular symbol
Output_data_plt_i386* plt_;
// The GOT PLT section.
Output_data_space* got_plt_;
+ // The GOT section for TLSDESC relocations.
+ Output_data_got<32, false>* got_tlsdesc_;
+ // The _GLOBAL_OFFSET_TABLE_ symbol.
+ Symbol* global_offset_table_;
// The dynamic reloc section.
Reloc_section* rel_dyn_;
// Relocs saved to avoid a COPY reloc.
false, // has_resolve
true, // has_code_fill
true, // is_default_stack_executable
+ true, // can_icf_inline_merge_sections
'\0', // wrap_char
"/usr/lib/libc.so.1", // dynamic_linker
0x08048000, // default_text_segment_address
0x1000, // abi_pagesize (overridable by -z max-page-size)
- 0x1000 // common_pagesize (overridable by -z common-page-size)
+ 0x1000, // common_pagesize (overridable by -z common-page-size)
+ elfcpp::SHN_UNDEF, // small_common_shndx
+ elfcpp::SHN_UNDEF, // large_common_shndx
+ 0, // small_common_section_flags
+ 0, // large_common_section_flags
+ NULL, // attributes_section
+ NULL // attributes_vendor
};
// Get the GOT section, creating it if necessary.
this->got_ = new Output_data_got<32, false>();
- 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.
+ layout->add_output_section_data(".got", elfcpp::SHT_PROGBITS,
+ (elfcpp::SHF_ALLOC
+ | elfcpp::SHF_WRITE),
+ this->got_, ORDER_RELRO_LAST, true);
+
this->got_plt_ = new Output_data_space(4, "** 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();
+ layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
+ (elfcpp::SHF_ALLOC
+ | elfcpp::SHF_WRITE),
+ this->got_plt_, ORDER_NON_RELRO_FIRST,
+ false);
// The first three entries are reserved.
this->got_plt_->set_current_data_size(3 * 4);
+ // Those bytes can go into the relro segment.
+ layout->increase_relro(3 * 4);
+
// Define _GLOBAL_OFFSET_TABLE_ at the start of the PLT.
- symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
- this->got_plt_,
- 0, 0, elfcpp::STT_OBJECT,
- elfcpp::STB_LOCAL,
- elfcpp::STV_HIDDEN, 0,
- false, false);
+ this->global_offset_table_ =
+ symtab->define_in_output_data("_GLOBAL_OFFSET_TABLE_", NULL,
+ Symbol_table::PREDEFINED,
+ this->got_plt_,
+ 0, 0, elfcpp::STT_OBJECT,
+ elfcpp::STB_LOCAL,
+ elfcpp::STV_HIDDEN, 0,
+ false, false);
+
+ // If there are any TLSDESC relocations, they get GOT entries in
+ // .got.plt after the jump slot entries.
+ this->got_tlsdesc_ = new Output_data_got<32, 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);
}
return this->got_;
gold_assert(layout != NULL);
this->rel_dyn_ = new Reloc_section(parameters->options().combreloc());
layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
- elfcpp::SHF_ALLOC, this->rel_dyn_);
+ elfcpp::SHF_ALLOC, this->rel_dyn_,
+ ORDER_DYNAMIC_RELOCS, false);
}
return this->rel_dyn_;
}
-// A class to handle the PLT data.
-
-class Output_data_plt_i386 : public Output_section_data
-{
- public:
- typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
-
- Output_data_plt_i386(Layout*, Output_data_space*);
-
- // Add an entry to the PLT.
- void
- add_entry(Symbol* gsym);
-
- // Return the .rel.plt section data.
- const Reloc_section*
- rel_plt() const
- { return this->rel_; }
-
- protected:
- 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;
-
- // The first entry in the PLT for an executable.
- static unsigned char exec_first_plt_entry[plt_entry_size];
-
- // The first entry in the PLT for a shared object.
- static unsigned char dyn_first_plt_entry[plt_entry_size];
-
- // Other entries in the PLT for an executable.
- static unsigned char exec_plt_entry[plt_entry_size];
-
- // Other entries in the PLT for a shared object.
- static unsigned char dyn_plt_entry[plt_entry_size];
-
- // Set the final size.
- void
- set_final_data_size()
- { this->set_data_size((this->count_ + 1) * plt_entry_size); }
-
- // Write out the PLT data.
- void
- do_write(Output_file*);
-
- // The reloc section.
- Reloc_section* rel_;
- // The .got.plt section.
- Output_data_space* got_plt_;
- // The number of PLT entries.
- unsigned int count_;
-};
-
// Create the PLT section. The ordinary .got section is an argument,
// since we need to refer to the start. We also create our own .got
// section just for PLT entries.
-Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
+Output_data_plt_i386::Output_data_plt_i386(Symbol_table* symtab,
+ Layout* layout,
Output_data_space* got_plt)
- : Output_section_data(4), got_plt_(got_plt), count_(0)
+ : Output_section_data(16), tls_desc_rel_(NULL), got_plt_(got_plt), count_(0),
+ global_ifuncs_(), local_ifuncs_()
{
this->rel_ = new Reloc_section(false);
layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
- elfcpp::SHF_ALLOC, this->rel_);
+ elfcpp::SHF_ALLOC, this->rel_,
+ ORDER_DYNAMIC_PLT_RELOCS, false);
+
+ if (parameters->doing_static_link())
+ {
+ // A statically linked executable will only have a .rel.plt
+ // section to hold R_386_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("__rel_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("__rel_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
this->got_plt_->set_current_data_size(got_offset + 4);
// Every PLT entry needs a reloc.
- gsym->set_needs_dynsym_entry();
- this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
- got_offset);
+ if (gsym->type() == elfcpp::STT_GNU_IFUNC
+ && gsym->can_use_relative_reloc(false))
+ {
+ this->rel_->add_symbolless_global_addend(gsym, elfcpp::R_386_IRELATIVE,
+ this->got_plt_, got_offset);
+ struct Global_ifunc gi;
+ gi.sym = gsym;
+ gi.got_offset = got_offset;
+ this->global_ifuncs_.push_back(gi);
+ }
+ else
+ {
+ gsym->set_needs_dynsym_entry();
+ this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
+ 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
// appear in the relocations.
}
+// Add an entry to the PLT for a local STT_GNU_IFUNC symbol. Return
+// the PLT offset.
+
+unsigned int
+Output_data_plt_i386::add_local_ifunc_entry(
+ Sized_relobj_file<32, false>* relobj,
+ unsigned int local_sym_index)
+{
+ unsigned int plt_offset = (this->count_ + 1) * plt_entry_size;
+ ++this->count_;
+
+ section_offset_type got_offset = this->got_plt_->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 + 4);
+
+ // Every PLT entry needs a reloc.
+ this->rel_->add_symbolless_local_addend(relobj, local_sym_index,
+ elfcpp::R_386_IRELATIVE,
+ this->got_plt_, got_offset);
+
+ struct Local_ifunc li;
+ li.object = relobj;
+ li.local_sym_index = local_sym_index;
+ li.got_offset = got_offset;
+ this->local_ifuncs_.push_back(li);
+
+ return plt_offset;
+}
+
+// Return where the TLS_DESC relocations should go, creating it if
+// necessary. These follow the JUMP_SLOT relocations.
+
+Output_data_plt_i386::Reloc_section*
+Output_data_plt_i386::rel_tls_desc(Layout* layout)
+{
+ if (this->tls_desc_rel_ == NULL)
+ {
+ this->tls_desc_rel_ = new Reloc_section(false);
+ layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
+ elfcpp::SHF_ALLOC, this->tls_desc_rel_,
+ ORDER_DYNAMIC_PLT_RELOCS, false);
+ gold_assert(this->tls_desc_rel_->output_section() ==
+ this->rel_->output_section());
+ }
+ return this->tls_desc_rel_;
+}
+
// The first entry in the PLT for an executable.
-unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] =
+const unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] =
{
0xff, 0x35, // pushl contents of memory address
0, 0, 0, 0, // replaced with address of .got + 4
// The first entry in the PLT for a shared object.
-unsigned char Output_data_plt_i386::dyn_first_plt_entry[plt_entry_size] =
+const unsigned char Output_data_plt_i386::dyn_first_plt_entry[plt_entry_size] =
{
0xff, 0xb3, 4, 0, 0, 0, // pushl 4(%ebx)
0xff, 0xa3, 8, 0, 0, 0, // jmp *8(%ebx)
// Subsequent entries in the PLT for an executable.
-unsigned char Output_data_plt_i386::exec_plt_entry[plt_entry_size] =
+const unsigned char Output_data_plt_i386::exec_plt_entry[plt_entry_size] =
{
0xff, 0x25, // jmp indirect
0, 0, 0, 0, // replaced with address of symbol in .got
// Subsequent entries in the PLT for a shared object.
-unsigned char Output_data_plt_i386::dyn_plt_entry[plt_entry_size] =
+const unsigned char Output_data_plt_i386::dyn_plt_entry[plt_entry_size] =
{
0xff, 0xa3, // jmp *offset(%ebx)
0, 0, 0, 0, // replaced with offset of symbol in .got
0, 0, 0, 0 // replaced with offset to start of .plt
};
+// The .eh_frame unwind information for the PLT.
+
+const unsigned char
+Output_data_plt_i386::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.
+ 0x7c, // Data alignment factor.
+ 8, // Return address column.
+ 1, // Augmentation size.
+ (elfcpp::DW_EH_PE_pcrel // FDE encoding.
+ | elfcpp::DW_EH_PE_sdata4),
+ elfcpp::DW_CFA_def_cfa, 4, 4, // DW_CFA_def_cfa: r4 (esp) ofs 4.
+ elfcpp::DW_CFA_offset + 8, 1, // DW_CFA_offset: r8 (eip) at cfa-4.
+ elfcpp::DW_CFA_nop, // Align to 16 bytes.
+ elfcpp::DW_CFA_nop
+};
+
+const unsigned char
+Output_data_plt_i386::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, 8, // DW_CFA_def_cfa_offset: 8.
+ elfcpp::DW_CFA_advance_loc + 6, // Advance 6 to __PLT__ + 6.
+ elfcpp::DW_CFA_def_cfa_offset, 12, // DW_CFA_def_cfa_offset: 12.
+ 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_breg4, 4, // Push %esp + 4.
+ elfcpp::DW_OP_breg8, 0, // Push %eip.
+ elfcpp::DW_OP_lit15, // Push 0xf.
+ elfcpp::DW_OP_and, // & (%eip & 0xf).
+ elfcpp::DW_OP_lit11, // Push 0xb.
+ elfcpp::DW_OP_ge, // >= ((%eip & 0xf) >= 0xb)
+ elfcpp::DW_OP_lit2, // Push 2.
+ elfcpp::DW_OP_shl, // << (((%eip & 0xf) >= 0xb) << 2)
+ elfcpp::DW_OP_plus, // + ((((%eip&0xf)>=0xb)<<2)+%esp+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 all specified by the i386 ELF
// Processor Supplement.
elfcpp::Elf_types<32>::Elf_Addr plt_address = this->address();
elfcpp::Elf_types<32>::Elf_Addr got_address = this->got_plt_->address();
- if (parameters->options().shared())
+ if (parameters->options().output_is_position_independent())
memcpy(pov, dyn_first_plt_entry, plt_entry_size);
else
{
{
// Set and adjust the PLT entry itself.
- if (parameters->options().shared())
+ if (parameters->options().output_is_position_independent())
{
memcpy(pov, dyn_plt_entry, plt_entry_size);
elfcpp::Swap_unaligned<32, false>::writeval(pov + 2, got_offset);
elfcpp::Swap<32, false>::writeval(got_pov, plt_address + plt_offset + 6);
}
+ // If any STT_GNU_IFUNC symbols have PLT entries, we need to change
+ // the GOT to point to the actual symbol value, rather than point to
+ // the PLT entry. That will let the dynamic linker call the right
+ // function when resolving IRELATIVE relocations.
+ for (std::vector<Global_ifunc>::const_iterator p =
+ this->global_ifuncs_.begin();
+ p != this->global_ifuncs_.end();
+ ++p)
+ {
+ const Sized_symbol<32>* ssym =
+ static_cast<const Sized_symbol<32>*>(p->sym);
+ elfcpp::Swap<32, false>::writeval(got_view + p->got_offset,
+ ssym->value());
+ }
+
+ for (std::vector<Local_ifunc>::const_iterator p =
+ this->local_ifuncs_.begin();
+ p != this->local_ifuncs_.end();
+ ++p)
+ {
+ const Symbol_value<32>* psymval =
+ p->object->local_symbol(p->local_sym_index);
+ elfcpp::Swap<32, false>::writeval(got_view + p->got_offset,
+ psymval->value(p->object, 0));
+ }
+
gold_assert(static_cast<section_size_type>(pov - oview) == oview_size);
gold_assert(static_cast<section_size_type>(got_pov - got_view) == got_size);
of->write_output_view(got_file_offset, got_size, got_view);
}
-// Create a PLT entry for a global symbol.
+// Create the PLT section.
void
-Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
+Target_i386::make_plt_section(Symbol_table* symtab, Layout* layout)
{
- if (gsym->has_plt_offset())
- return;
-
if (this->plt_ == NULL)
{
// Create the GOT sections first.
this->got_section(symtab, layout);
- this->plt_ = new Output_data_plt_i386(layout, this->got_plt_);
+ this->plt_ = new Output_data_plt_i386(symtab, layout, this->got_plt_);
layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
(elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR),
- this->plt_);
+ this->plt_, ORDER_PLT, false);
+
+ // Make the sh_info field of .rel.plt point to .plt.
+ Output_section* rel_plt_os = this->plt_->rel_plt()->output_section();
+ rel_plt_os->set_info_section(this->plt_->output_section());
}
+}
+// Create a PLT entry for a global symbol.
+
+void
+Target_i386::make_plt_entry(Symbol_table* symtab, Layout* layout, Symbol* gsym)
+{
+ if (gsym->has_plt_offset())
+ return;
+ if (this->plt_ == NULL)
+ this->make_plt_section(symtab, layout);
this->plt_->add_entry(gsym);
}
+// Make a PLT entry for a local STT_GNU_IFUNC symbol.
+
+void
+Target_i386::make_local_ifunc_plt_entry(Symbol_table* symtab, Layout* layout,
+ Sized_relobj_file<32, false>* relobj,
+ unsigned int local_sym_index)
+{
+ if (relobj->local_has_plt_offset(local_sym_index))
+ return;
+ if (this->plt_ == NULL)
+ this->make_plt_section(symtab, layout);
+ unsigned int plt_offset = this->plt_->add_local_ifunc_entry(relobj,
+ local_sym_index);
+ relobj->set_local_plt_offset(local_sym_index, plt_offset);
+}
+
+// Return the number of entries in the PLT.
+
+unsigned int
+Target_i386::plt_entry_count() const
+{
+ if (this->plt_ == NULL)
+ return 0;
+ return this->plt_->entry_count();
+}
+
+// Return the offset of the first non-reserved PLT entry.
+
+unsigned int
+Target_i386::first_plt_entry_offset() const
+{
+ return Output_data_plt_i386::first_plt_entry_offset();
+}
+
+// Return the size of each PLT entry.
+
+unsigned int
+Target_i386::plt_entry_size() const
+{
+ return Output_data_plt_i386::get_plt_entry_size();
+}
+
+// Get the section to use for TLS_DESC relocations.
+
+Target_i386::Reloc_section*
+Target_i386::rel_tls_desc_section(Layout* layout) const
+{
+ return this->plt_section()->rel_tls_desc(layout);
+}
+
// Define the _TLS_MODULE_BASE_ symbol in the TLS segment.
void
{
bool is_exec = parameters->options().output_is_executable();
symtab->define_in_output_segment("_TLS_MODULE_BASE_", NULL,
+ Symbol_table::PREDEFINED,
tls_segment, 0, 0,
elfcpp::STT_TLS,
elfcpp::STB_LOCAL,
unsigned int
Target_i386::got_mod_index_entry(Symbol_table* symtab, Layout* layout,
- Sized_relobj<32, false>* object)
+ Sized_relobj_file<32, false>* object)
{
if (this->got_mod_index_offset_ == -1U)
{
}
}
+// Get the Reference_flags for a particular relocation.
+
+int
+Target_i386::Scan::get_reference_flags(unsigned int r_type)
+{
+ switch (r_type)
+ {
+ case elfcpp::R_386_NONE:
+ case elfcpp::R_386_GNU_VTINHERIT:
+ case elfcpp::R_386_GNU_VTENTRY:
+ case elfcpp::R_386_GOTPC:
+ // No symbol reference.
+ return 0;
+
+ case elfcpp::R_386_32:
+ case elfcpp::R_386_16:
+ case elfcpp::R_386_8:
+ return Symbol::ABSOLUTE_REF;
+
+ case elfcpp::R_386_PC32:
+ case elfcpp::R_386_PC16:
+ case elfcpp::R_386_PC8:
+ case elfcpp::R_386_GOTOFF:
+ return Symbol::RELATIVE_REF;
+
+ case elfcpp::R_386_PLT32:
+ return Symbol::FUNCTION_CALL | Symbol::RELATIVE_REF;
+
+ case elfcpp::R_386_GOT32:
+ // Absolute in GOT.
+ return Symbol::ABSOLUTE_REF;
+
+ case elfcpp::R_386_TLS_GD: // Global-dynamic
+ case elfcpp::R_386_TLS_GOTDESC: // Global-dynamic (from ~oliva url)
+ case elfcpp::R_386_TLS_DESC_CALL:
+ case elfcpp::R_386_TLS_LDM: // Local-dynamic
+ case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
+ case elfcpp::R_386_TLS_IE: // Initial-exec
+ case elfcpp::R_386_TLS_IE_32:
+ case elfcpp::R_386_TLS_GOTIE:
+ case elfcpp::R_386_TLS_LE: // Local-exec
+ case elfcpp::R_386_TLS_LE_32:
+ return Symbol::TLS_REF;
+
+ case elfcpp::R_386_COPY:
+ case elfcpp::R_386_GLOB_DAT:
+ case elfcpp::R_386_JUMP_SLOT:
+ case elfcpp::R_386_RELATIVE:
+ case elfcpp::R_386_IRELATIVE:
+ case elfcpp::R_386_TLS_TPOFF:
+ case elfcpp::R_386_TLS_DTPMOD32:
+ case elfcpp::R_386_TLS_DTPOFF32:
+ case elfcpp::R_386_TLS_TPOFF32:
+ case elfcpp::R_386_TLS_DESC:
+ case elfcpp::R_386_32PLT:
+ case elfcpp::R_386_TLS_GD_32:
+ case elfcpp::R_386_TLS_GD_PUSH:
+ case elfcpp::R_386_TLS_GD_CALL:
+ case elfcpp::R_386_TLS_GD_POP:
+ case elfcpp::R_386_TLS_LDM_32:
+ case elfcpp::R_386_TLS_LDM_PUSH:
+ case elfcpp::R_386_TLS_LDM_CALL:
+ case elfcpp::R_386_TLS_LDM_POP:
+ case elfcpp::R_386_USED_BY_INTEL_200:
+ default:
+ // Not expected. We will give an error later.
+ return 0;
+ }
+}
+
// Report an unsupported relocation against a local symbol.
void
-Target_i386::Scan::unsupported_reloc_local(Sized_relobj<32, false>* object,
+Target_i386::Scan::unsupported_reloc_local(Sized_relobj_file<32, false>* object,
unsigned int r_type)
{
gold_error(_("%s: unsupported reloc %u against local symbol"),
object->name().c_str(), r_type);
}
+// Return whether we need to make a PLT entry for a relocation of a
+// given type against a STT_GNU_IFUNC symbol.
+
+bool
+Target_i386::Scan::reloc_needs_plt_for_ifunc(
+ Sized_relobj_file<32, false>* object,
+ unsigned int r_type)
+{
+ int flags = Scan::get_reference_flags(r_type);
+ if (flags & Symbol::TLS_REF)
+ gold_error(_("%s: unsupported TLS reloc %u for IFUNC symbol"),
+ object->name().c_str(), r_type);
+ return flags != 0;
+}
+
// Scan a relocation for a local symbol.
inline void
-Target_i386::Scan::local(const General_options&,
- Symbol_table* symtab,
+Target_i386::Scan::local(Symbol_table* symtab,
Layout* layout,
Target_i386* target,
- Sized_relobj<32, false>* object,
+ Sized_relobj_file<32, false>* object,
unsigned int data_shndx,
Output_section* output_section,
const elfcpp::Rel<32, false>& reloc,
unsigned int r_type,
const elfcpp::Sym<32, 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))
+ {
+ unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
+ target->make_local_ifunc_plt_entry(symtab, layout, object, r_sym);
+ }
+
switch (r_type)
{
case elfcpp::R_386_NONE:
{
Reloc_section* rel_dyn = target->rel_dyn_section(layout);
unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
- rel_dyn->add_local_relative(object, r_sym, elfcpp::R_386_RELATIVE,
- output_section, data_shndx,
- reloc.get_r_offset());
+ rel_dyn->add_local_relative(object, r_sym, elfcpp::R_386_RELATIVE,
+ output_section, data_shndx,
+ reloc.get_r_offset());
}
break;
// The symbol requires a GOT entry.
Output_data_got<32, false>* got = target->got_section(symtab, layout);
unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
- if (got->add_local(object, r_sym, GOT_TYPE_STANDARD))
+
+ // For a STT_GNU_IFUNC symbol we want the PLT offset. That
+ // 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)
+ is_new = got->add_local_plt(object, r_sym, GOT_TYPE_STANDARD);
+ else
+ is_new = got->add_local(object, r_sym, GOT_TYPE_STANDARD);
+ if (is_new)
{
// If we are generating a shared object, we need to add a
// dynamic RELATIVE relocation for this symbol's GOT entry.
if (parameters->options().output_is_position_independent())
{
Reloc_section* rel_dyn = target->rel_dyn_section(layout);
- unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
- rel_dyn->add_local_relative(
- object, r_sym, elfcpp::R_386_RELATIVE, got,
- object->local_got_offset(r_sym, GOT_TYPE_STANDARD));
+ unsigned int got_offset =
+ object->local_got_offset(r_sym, GOT_TYPE_STANDARD);
+ rel_dyn->add_local_relative(object, r_sym,
+ elfcpp::R_386_RELATIVE,
+ got, got_offset);
}
}
}
case elfcpp::R_386_GLOB_DAT:
case elfcpp::R_386_JUMP_SLOT:
case elfcpp::R_386_RELATIVE:
+ case elfcpp::R_386_IRELATIVE:
case elfcpp::R_386_TLS_TPOFF:
case elfcpp::R_386_TLS_DTPMOD32:
case elfcpp::R_386_TLS_DTPOFF32:
target->define_tls_base_symbol(symtab, layout);
if (optimized_type == tls::TLSOPT_NONE)
{
- // Create a double GOT entry with an R_386_TLS_DESC reloc.
- Output_data_got<32, false>* got
- = target->got_section(symtab, layout);
+ // Create a double GOT entry with an R_386_TLS_DESC
+ // reloc. The R_386_TLS_DESC reloc is resolved
+ // lazily, so the GOT entry needs to be in an area in
+ // .got.plt, not .got. Call got_section to make sure
+ // the section has been created.
+ target->got_section(symtab, layout);
+ Output_data_got<32, false>* got = target->got_tlsdesc_section();
unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
- 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_rel(object, r_sym, shndx,
- GOT_TYPE_TLS_DESC,
- target->rel_dyn_section(layout),
- elfcpp::R_386_TLS_DESC, 0);
+ if (!object->local_has_got_offset(r_sym, GOT_TYPE_TLS_DESC))
+ {
+ unsigned int got_offset = got->add_constant(0);
+ // The local symbol value is stored in the second
+ // GOT entry.
+ got->add_local(object, r_sym, GOT_TYPE_TLS_DESC);
+ // That set the GOT offset of the local symbol to
+ // point to the second entry, but we want it to
+ // point to the first.
+ object->set_local_got_offset(r_sym, GOT_TYPE_TLS_DESC,
+ got_offset);
+ Reloc_section* rt = target->rel_tls_desc_section(layout);
+ rt->add_absolute(elfcpp::R_386_TLS_DESC, got, got_offset);
+ }
}
else if (optimized_type != tls::TLSOPT_TO_LE)
unsupported_reloc_local(object, r_type);
// Report an unsupported relocation against a global symbol.
void
-Target_i386::Scan::unsupported_reloc_global(Sized_relobj<32, false>* object,
- unsigned int r_type,
- Symbol* gsym)
+Target_i386::Scan::unsupported_reloc_global(
+ Sized_relobj_file<32, false>* object,
+ unsigned int r_type,
+ Symbol* gsym)
{
gold_error(_("%s: unsupported reloc %u against global symbol %s"),
object->name().c_str(), r_type, gsym->demangled_name().c_str());
}
+inline bool
+Target_i386::Scan::possible_function_pointer_reloc(unsigned int r_type)
+{
+ switch (r_type)
+ {
+ case elfcpp::R_386_32:
+ case elfcpp::R_386_16:
+ case elfcpp::R_386_8:
+ case elfcpp::R_386_GOTOFF:
+ case elfcpp::R_386_GOT32:
+ {
+ return true;
+ }
+ default:
+ return false;
+ }
+ return false;
+}
+
+inline bool
+Target_i386::Scan::local_reloc_may_be_function_pointer(
+ Symbol_table* ,
+ Layout* ,
+ Target_i386* ,
+ Sized_relobj_file<32, false>* ,
+ unsigned int ,
+ Output_section* ,
+ const elfcpp::Rel<32, false>& ,
+ unsigned int r_type,
+ const elfcpp::Sym<32, false>&)
+{
+ return possible_function_pointer_reloc(r_type);
+}
+
+inline bool
+Target_i386::Scan::global_reloc_may_be_function_pointer(
+ Symbol_table* ,
+ Layout* ,
+ Target_i386* ,
+ Sized_relobj_file<32, false>* ,
+ unsigned int ,
+ Output_section* ,
+ const elfcpp::Rel<32, false>& ,
+ unsigned int r_type,
+ Symbol*)
+{
+ return possible_function_pointer_reloc(r_type);
+}
+
// Scan a relocation for a global symbol.
inline void
-Target_i386::Scan::global(const General_options&,
- Symbol_table* symtab,
+Target_i386::Scan::global(Symbol_table* symtab,
Layout* layout,
Target_i386* target,
- Sized_relobj<32, false>* object,
+ Sized_relobj_file<32, false>* object,
unsigned int data_shndx,
Output_section* output_section,
const elfcpp::Rel<32, false>& reloc,
unsigned int r_type,
Symbol* gsym)
{
+ // A STT_GNU_IFUNC symbol may require a PLT entry.
+ if (gsym->type() == elfcpp::STT_GNU_IFUNC
+ && this->reloc_needs_plt_for_ifunc(object, r_type))
+ target->make_plt_entry(symtab, layout, gsym);
+
switch (r_type)
{
case elfcpp::R_386_NONE:
gsym->set_needs_dynsym_value();
}
// Make a dynamic relocation if necessary.
- if (gsym->needs_dynamic_reloc(Symbol::ABSOLUTE_REF))
+ if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
{
- if (target->may_need_copy_reloc(gsym))
+ if (gsym->may_need_copy_reloc())
{
target->copy_reloc(symtab, layout, object,
data_shndx, output_section, gsym, reloc);
}
+ else if (r_type == elfcpp::R_386_32
+ && gsym->type() == elfcpp::STT_GNU_IFUNC
+ && gsym->can_use_relative_reloc(false)
+ && !gsym->is_from_dynobj()
+ && !gsym->is_undefined()
+ && !gsym->is_preemptible())
+ {
+ // Use an IRELATIVE reloc for a locally defined
+ // 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* rel_dyn = target->rel_dyn_section(layout);
+ rel_dyn->add_symbolless_global_addend(gsym,
+ elfcpp::R_386_IRELATIVE,
+ output_section,
+ object, data_shndx,
+ reloc.get_r_offset());
+ }
else if (r_type == elfcpp::R_386_32
&& gsym->can_use_relative_reloc(false))
{
Reloc_section* rel_dyn = target->rel_dyn_section(layout);
- rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
- output_section, object,
- data_shndx, reloc.get_r_offset());
+ rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
+ output_section, object,
+ data_shndx, reloc.get_r_offset());
}
else
{
target->make_plt_entry(symtab, layout, gsym);
}
// Make a dynamic relocation if necessary.
- int flags = Symbol::NON_PIC_REF;
- if (gsym->type() == elfcpp::STT_FUNC)
- flags |= Symbol::FUNCTION_CALL;
- if (gsym->needs_dynamic_reloc(flags))
+ if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
{
- if (target->may_need_copy_reloc(gsym))
+ if (gsym->may_need_copy_reloc())
{
target->copy_reloc(symtab, layout, object,
data_shndx, output_section, gsym, reloc);
// The symbol requires a GOT entry.
Output_data_got<32, false>* got = target->got_section(symtab, layout);
if (gsym->final_value_is_known())
- got->add_global(gsym, GOT_TYPE_STANDARD);
+ {
+ // For a STT_GNU_IFUNC symbol we want the PLT address.
+ if (gsym->type() == elfcpp::STT_GNU_IFUNC)
+ got->add_global_plt(gsym, GOT_TYPE_STANDARD);
+ else
+ got->add_global(gsym, GOT_TYPE_STANDARD);
+ }
else
{
// If this symbol is not fully resolved, we need to add a
Reloc_section* rel_dyn = target->rel_dyn_section(layout);
if (gsym->is_from_dynobj()
|| gsym->is_undefined()
- || gsym->is_preemptible())
+ || gsym->is_preemptible()
+ || (gsym->type() == elfcpp::STT_GNU_IFUNC
+ && parameters->options().output_is_position_independent()))
got->add_global_with_rel(gsym, GOT_TYPE_STANDARD,
rel_dyn, elfcpp::R_386_GLOB_DAT);
else
{
- if (got->add_global(gsym, GOT_TYPE_STANDARD))
- rel_dyn->add_global_relative(
- gsym, elfcpp::R_386_RELATIVE, got,
- gsym->got_offset(GOT_TYPE_STANDARD));
+ // For a STT_GNU_IFUNC symbol we want to write the PLT
+ // offset into the GOT, so that function pointer
+ // comparisons work correctly.
+ bool is_new;
+ if (gsym->type() != elfcpp::STT_GNU_IFUNC)
+ is_new = got->add_global(gsym, GOT_TYPE_STANDARD);
+ else
+ {
+ is_new = got->add_global_plt(gsym, GOT_TYPE_STANDARD);
+ // Tell the dynamic linker to use the PLT address
+ // when resolving relocations.
+ if (gsym->is_from_dynobj()
+ && !parameters->options().shared())
+ gsym->set_needs_dynsym_value();
+ }
+ if (is_new)
+ {
+ unsigned int got_off = gsym->got_offset(GOT_TYPE_STANDARD);
+ rel_dyn->add_global_relative(gsym, elfcpp::R_386_RELATIVE,
+ got, got_off);
+ }
}
}
}
case elfcpp::R_386_GLOB_DAT:
case elfcpp::R_386_JUMP_SLOT:
case elfcpp::R_386_RELATIVE:
+ case elfcpp::R_386_IRELATIVE:
case elfcpp::R_386_TLS_TPOFF:
case elfcpp::R_386_TLS_DTPMOD32:
case elfcpp::R_386_TLS_DTPOFF32:
target->define_tls_base_symbol(symtab, layout);
if (optimized_type == tls::TLSOPT_NONE)
{
- // Create a double GOT entry with an R_386_TLS_DESC reloc.
- Output_data_got<32, false>* got
- = target->got_section(symtab, layout);
- got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC,
- target->rel_dyn_section(layout),
+ // Create a double GOT entry with an R_386_TLS_DESC
+ // reloc. The R_386_TLS_DESC reloc is resolved
+ // lazily, so the GOT entry needs to be in an area in
+ // .got.plt, not .got. Call got_section to make sure
+ // the section has been created.
+ target->got_section(symtab, layout);
+ Output_data_got<32, false>* got = target->got_tlsdesc_section();
+ Reloc_section* rt = target->rel_tls_desc_section(layout);
+ got->add_global_pair_with_rel(gsym, GOT_TYPE_TLS_DESC, rt,
elfcpp::R_386_TLS_DESC, 0);
}
else if (optimized_type == tls::TLSOPT_TO_IE)
// Process relocations for gc.
void
-Target_i386::gc_process_relocs(const General_options& options,
- Symbol_table* symtab,
+Target_i386::gc_process_relocs(Symbol_table* symtab,
Layout* layout,
- Sized_relobj<32, false>* object,
+ Sized_relobj_file<32, false>* object,
unsigned int data_shndx,
unsigned int,
const unsigned char* prelocs,
const unsigned char* plocal_symbols)
{
gold::gc_process_relocs<32, false, Target_i386, elfcpp::SHT_REL,
- Target_i386::Scan>(
- options,
+ Target_i386::Scan,
+ Target_i386::Relocatable_size_for_reloc>(
symtab,
layout,
this,
// Scan relocations for a section.
void
-Target_i386::scan_relocs(const General_options& options,
- Symbol_table* symtab,
+Target_i386::scan_relocs(Symbol_table* symtab,
Layout* layout,
- Sized_relobj<32, false>* object,
+ Sized_relobj_file<32, false>* object,
unsigned int data_shndx,
unsigned int sh_type,
const unsigned char* prelocs,
gold::scan_relocs<32, false, Target_i386, elfcpp::SHT_REL,
Target_i386::Scan>(
- options,
symtab,
layout,
this,
// Finalize the sections.
void
-Target_i386::do_finalize_sections(Layout* layout)
+Target_i386::do_finalize_sections(
+ Layout* layout,
+ const Input_objects*,
+ Symbol_table* symtab)
{
- // Fill in some more dynamic tags.
- Output_data_dynamic* const odyn = layout->dynamic_data();
- if (odyn != NULL)
- {
- if (this->got_plt_ != NULL)
- odyn->add_section_address(elfcpp::DT_PLTGOT, this->got_plt_);
-
- if (this->plt_ != NULL)
- {
- const Output_data* od = this->plt_->rel_plt();
- odyn->add_section_size(elfcpp::DT_PLTRELSZ, od);
- odyn->add_section_address(elfcpp::DT_JMPREL, od);
- odyn->add_constant(elfcpp::DT_PLTREL, elfcpp::DT_REL);
- }
-
- if (this->rel_dyn_ != NULL)
- {
- const Output_data* od = this->rel_dyn_;
- odyn->add_section_address(elfcpp::DT_REL, od);
- odyn->add_section_size(elfcpp::DT_RELSZ, od);
- odyn->add_constant(elfcpp::DT_RELENT,
- elfcpp::Elf_sizes<32>::rel_size);
- }
-
- if (!parameters->options().shared())
- {
- // The value of the DT_DEBUG tag is filled in by the dynamic
- // linker at run time, and used by the debugger.
- odyn->add_constant(elfcpp::DT_DEBUG, 0);
- }
- }
+ const Reloc_section* rel_plt = (this->plt_ == NULL
+ ? NULL
+ : this->plt_->rel_plt());
+ layout->add_target_dynamic_tags(true, this->got_plt_, rel_plt,
+ this->rel_dyn_, true, false);
// Emit any relocs we saved in an attempt to avoid generating COPY
// relocs.
if (this->copy_relocs_.any_saved_relocs())
this->copy_relocs_.emit(this->rel_dyn_section(layout));
+
+ // Set the size of the _GLOBAL_OFFSET_TABLE_ symbol to the size of
+ // the .got.plt section.
+ Symbol* sym = this->global_offset_table_;
+ if (sym != NULL)
+ {
+ uint32_t data_size = this->got_plt_->current_data_size();
+ symtab->get_sized_symbol<32>(sym)->set_symsize(data_size);
+ }
}
// Return whether a direct absolute static relocation needs to be applied.
inline bool
Target_i386::Relocate::should_apply_static_reloc(const Sized_symbol<32>* gsym,
- int ref_flags,
+ unsigned int r_type,
bool is_32bit,
Output_section* output_section)
{
if ((output_section->flags() & elfcpp::SHF_ALLOC) == 0)
return true;
+ int ref_flags = Scan::get_reference_flags(r_type);
+
// For local symbols, we will have created a non-RELATIVE dynamic
// relocation only if (a) the output is position independent,
// (b) the relocation is absolute (not pc- or segment-relative), and
inline bool
Target_i386::Relocate::relocate(const Relocate_info<32, false>* relinfo,
Target_i386* target,
- Output_section *output_section,
+ Output_section* output_section,
size_t relnum,
const elfcpp::Rel<32, false>& rel,
unsigned int r_type,
}
}
+ const Sized_relobj_file<32, false>* object = relinfo->object;
+
// Pick the value to use for symbols defined in shared objects.
Symbol_value<32> symval;
if (gsym != NULL
- && gsym->use_plt_offset(r_type == elfcpp::R_386_PC8
- || r_type == elfcpp::R_386_PC16
- || r_type == elfcpp::R_386_PC32))
+ && gsym->type() == elfcpp::STT_GNU_IFUNC
+ && r_type == elfcpp::R_386_32
+ && gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type))
+ && gsym->can_use_relative_reloc(false)
+ && !gsym->is_from_dynobj()
+ && !gsym->is_undefined()
+ && !gsym->is_preemptible())
+ {
+ // In this case we are generating a R_386_IRELATIVE reloc. We
+ // want to use the real value of the symbol, not the PLT offset.
+ }
+ else if (gsym != NULL
+ && gsym->use_plt_offset(Scan::get_reference_flags(r_type)))
{
symval.set_output_value(target->plt_section()->address()
+ gsym->plt_offset());
psymval = &symval;
}
-
- const Sized_relobj<32, false>* object = relinfo->object;
+ else if (gsym == NULL && psymval->is_ifunc_symbol())
+ {
+ unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
+ if (object->local_has_plt_offset(r_sym))
+ {
+ symval.set_output_value(target->plt_section()->address()
+ + object->local_plt_offset(r_sym));
+ psymval = &symval;
+ }
+ }
// Get the GOT offset if needed.
// The GOT pointer points to the end of the GOT section.
break;
case elfcpp::R_386_32:
- if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, true,
- output_section))
+ if (should_apply_static_reloc(gsym, r_type, true, output_section))
Relocate_functions<32, false>::rel32(view, object, psymval);
break;
case elfcpp::R_386_PC32:
- {
- int ref_flags = Symbol::NON_PIC_REF;
- if (gsym != NULL && gsym->type() == elfcpp::STT_FUNC)
- ref_flags |= Symbol::FUNCTION_CALL;
- if (should_apply_static_reloc(gsym, ref_flags, true, output_section))
- Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
- }
+ if (should_apply_static_reloc(gsym, r_type, true, output_section))
+ Relocate_functions<32, false>::pcrel32(view, object, psymval, address);
break;
case elfcpp::R_386_16:
- if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false,
- output_section))
+ if (should_apply_static_reloc(gsym, r_type, false, output_section))
Relocate_functions<32, false>::rel16(view, object, psymval);
break;
case elfcpp::R_386_PC16:
- {
- int ref_flags = Symbol::NON_PIC_REF;
- if (gsym != NULL && gsym->type() == elfcpp::STT_FUNC)
- ref_flags |= Symbol::FUNCTION_CALL;
- if (should_apply_static_reloc(gsym, ref_flags, false, output_section))
- Relocate_functions<32, false>::pcrel16(view, object, psymval, address);
- }
+ if (should_apply_static_reloc(gsym, r_type, false, output_section))
+ Relocate_functions<32, false>::pcrel16(view, object, psymval, address);
break;
case elfcpp::R_386_8:
- if (should_apply_static_reloc(gsym, Symbol::ABSOLUTE_REF, false,
- output_section))
+ if (should_apply_static_reloc(gsym, r_type, false, output_section))
Relocate_functions<32, false>::rel8(view, object, psymval);
break;
case elfcpp::R_386_PC8:
- {
- int ref_flags = Symbol::NON_PIC_REF;
- if (gsym != NULL && gsym->type() == elfcpp::STT_FUNC)
- ref_flags |= Symbol::FUNCTION_CALL;
- if (should_apply_static_reloc(gsym, ref_flags, false,
- output_section))
- Relocate_functions<32, false>::pcrel8(view, object, psymval, address);
- }
+ if (should_apply_static_reloc(gsym, r_type, false, output_section))
+ Relocate_functions<32, false>::pcrel8(view, object, psymval, address);
break;
case elfcpp::R_386_PLT32:
case elfcpp::R_386_GLOB_DAT:
case elfcpp::R_386_JUMP_SLOT:
case elfcpp::R_386_RELATIVE:
+ case elfcpp::R_386_IRELATIVE:
// These are outstanding tls relocs, which are unexpected when
// linking.
case elfcpp::R_386_TLS_TPOFF:
{
Output_segment* tls_segment = relinfo->layout->tls_segment();
- const Sized_relobj<32, false>* object = relinfo->object;
+ const Sized_relobj_file<32, false>* object = relinfo->object;
elfcpp::Elf_types<32>::Elf_Addr value = psymval->value(object, 0);
- const bool is_final =
- (gsym == NULL
- ? !parameters->options().output_is_position_independent()
- : gsym->final_value_is_known());
+ const bool is_final = (gsym == NULL
+ ? !parameters->options().shared()
+ : gsym->final_value_is_known());
const tls::Tls_optimization optimized_type
= Target_i386::optimize_tls_reloc(is_final, r_type);
switch (r_type)
unsigned int got_type = (optimized_type == tls::TLSOPT_TO_IE
? GOT_TYPE_TLS_NOFFSET
: GOT_TYPE_TLS_DESC);
- unsigned int got_offset;
+ unsigned int got_offset = 0;
+ if (r_type == elfcpp::R_386_TLS_GOTDESC
+ && optimized_type == tls::TLSOPT_NONE)
+ {
+ // We created GOT entries in the .got.tlsdesc portion of
+ // the .got.plt section, but the offset stored in the
+ // symbol is the offset within .got.tlsdesc.
+ got_offset = (target->got_size()
+ + target->got_plt_section()->data_size());
+ }
if (gsym != NULL)
{
gold_assert(gsym->has_got_offset(got_type));
- got_offset = gsym->got_offset(got_type) - target->got_size();
+ got_offset += gsym->got_offset(got_type) - target->got_size();
}
else
{
unsigned int r_sym = elfcpp::elf_r_sym<32>(rel.get_r_info());
gold_assert(object->local_has_got_offset(r_sym, got_type));
- got_offset = (object->local_got_offset(r_sym, got_type)
- - target->got_size());
+ got_offset += (object->local_got_offset(r_sym, got_type)
+ - target->got_size());
}
if (optimized_type == tls::TLSOPT_TO_IE)
{
break;
case elfcpp::R_386_TLS_LDO_32: // Alternate local-dynamic
- // This reloc can appear in debugging sections, in which case we
- // won't see the TLS_LDM reloc. The local_dynamic_type field
- // tells us this.
- if (optimized_type == tls::TLSOPT_TO_LE
- && this->local_dynamic_type_ != LOCAL_DYNAMIC_NONE)
+ if (optimized_type == tls::TLSOPT_TO_LE)
{
- gold_assert(tls_segment != NULL);
- value -= tls_segment->memsz();
+ // This reloc can appear in debugging sections, in which
+ // case we must not convert to local-exec. We decide what
+ // to do based on whether the section is marked as
+ // containing executable code. That is what the GNU linker
+ // does as well.
+ elfcpp::Shdr<32, false> shdr(relinfo->data_shdr);
+ if ((shdr.get_sh_flags() & elfcpp::SHF_EXECINSTR) != 0)
+ {
+ gold_assert(tls_segment != NULL);
+ value -= tls_segment->memsz();
+ }
}
Relocate_functions<32, false>::rel32(view, value);
break;
bool needs_special_offset_handling,
unsigned char* view,
elfcpp::Elf_types<32>::Elf_Addr address,
- section_size_type view_size)
+ section_size_type view_size,
+ const Reloc_symbol_changes* reloc_symbol_changes)
{
gold_assert(sh_type == elfcpp::SHT_REL);
needs_special_offset_handling,
view,
address,
- view_size);
+ view_size,
+ reloc_symbol_changes);
}
// Return the size of a relocation while scanning during a relocatable
case elfcpp::R_386_GLOB_DAT:
case elfcpp::R_386_JUMP_SLOT:
case elfcpp::R_386_RELATIVE:
+ case elfcpp::R_386_IRELATIVE:
case elfcpp::R_386_TLS_TPOFF:
case elfcpp::R_386_TLS_DTPMOD32:
case elfcpp::R_386_TLS_DTPOFF32:
// Scan the relocs during a relocatable link.
void
-Target_i386::scan_relocatable_relocs(const General_options& options,
- Symbol_table* symtab,
+Target_i386::scan_relocatable_relocs(Symbol_table* symtab,
Layout* layout,
- Sized_relobj<32, false>* object,
+ Sized_relobj_file<32, false>* object,
unsigned int data_shndx,
unsigned int sh_type,
const unsigned char* prelocs,
gold::scan_relocatable_relocs<32, false, elfcpp::SHT_REL,
Scan_relocatable_relocs>(
- options,
symtab,
layout,
object,
return std::string(nops[length], length);
}
+// Return whether SYM should be treated as a call to a non-split
+// function. We don't want that to be true of a call to a
+// get_pc_thunk function.
+
+bool
+Target_i386::do_is_call_to_non_split(const Symbol* sym, unsigned int) const
+{
+ return (sym->type() == elfcpp::STT_FUNC
+ && !is_prefix_of("__i686.get_pc_thunk.", sym->name()));
+}
+
+// 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
+// that it has enough stack space to run some random function.
+
+void
+Target_i386::do_calls_non_split(Relobj* object, unsigned int shndx,
+ section_offset_type fnoffset,
+ section_size_type fnsize,
+ unsigned char* view,
+ section_size_type view_size,
+ std::string* from,
+ std::string* to) const
+{
+ // The function starts with a comparison of the stack pointer and a
+ // field in the TCB. This is followed by a jump.
+
+ // cmp %gs:NN,%esp
+ if (this->match_view(view, view_size, fnoffset, "\x65\x3b\x25", 3)
+ && fnsize > 7)
+ {
+ // We will call __morestack if the carry flag is set after this
+ // comparison. We turn the comparison into an stc instruction
+ // and some nops.
+ view[fnoffset] = '\xf9';
+ this->set_view_to_nop(view, view_size, fnoffset + 1, 6);
+ }
+ // lea NN(%esp),%ecx
+ // lea NN(%esp),%edx
+ else if ((this->match_view(view, view_size, fnoffset, "\x8d\x8c\x24", 3)
+ || this->match_view(view, view_size, fnoffset, "\x8d\x94\x24", 3))
+ && fnsize > 7)
+ {
+ // This is loading an offset from the stack pointer for a
+ // comparison. The offset is negative, so we decrease the
+ // offset by the amount of space we need for the stack. This
+ // means we will avoid calling __morestack if there happens to
+ // be plenty of space on the stack already.
+ unsigned char* pval = view + fnoffset + 3;
+ uint32_t val = elfcpp::Swap_unaligned<32, false>::readval(pval);
+ val -= parameters->options().split_stack_adjust_size();
+ elfcpp::Swap_unaligned<32, false>::writeval(pval, val);
+ }
+ else
+ {
+ if (!object->has_no_split_stack())
+ object->error(_("failed to match split-stack sequence at "
+ "section %u offset %0zx"),
+ shndx, static_cast<size_t>(fnoffset));
+ return;
+ }
+
+ // We have to change the function so that it calls
+ // __morestack_non_split instead of __morestack. The former will
+ // allocate additional stack space.
+ *from = "__morestack";
+ *to = "__morestack_non_split";
+}
+
// The selector for i386 object files.
class Target_selector_i386 : public Target_selector_freebsd
public:
Target_selector_i386()
: Target_selector_freebsd(elfcpp::EM_386, 32, false,
- "elf32-i386", "elf32-i386-freebsd")
+ "elf32-i386", "elf32-i386-freebsd",
+ "elf_i386")
{ }
Target*
projects / deliverable / binutils-gdb.git / blobdiff