// i386.cc -- i386 target support for gold.
-// Copyright 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013
-// Free Software Foundation, Inc.
+// Copyright (C) 2006-2015 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
using namespace gold;
+// A class to handle the .got.plt section.
+
+class Output_data_got_plt_i386 : public Output_section_data_build
+{
+ public:
+ Output_data_got_plt_i386(Layout* layout)
+ : Output_section_data_build(4),
+ layout_(layout)
+ { }
+
+ protected:
+ // Write out the PLT data.
+ void
+ do_write(Output_file*);
+
+ // Write to a map file.
+ void
+ do_print_to_mapfile(Mapfile* mapfile) const
+ { mapfile->print_output_data(this, "** GOT PLT"); }
+
+ private:
+ // A pointer to the Layout class, so that we can find the .dynamic
+ // section when we write out the GOT PLT section.
+ Layout* layout_;
+};
+
// A class to handle the PLT data.
// This is an abstract base class that handles most of the linker details
// but does not know the actual contents of PLT entries. The derived
typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
Output_data_plt_i386(Layout*, uint64_t addralign,
- Output_data_space*, Output_data_space*);
+ Output_data_got_plt_i386*, Output_data_space*);
// Add an entry to the PLT.
void
unsigned int got_offset;
};
- // 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 TLS_DESC relocations, if necessary. These must follow the
// regular relocatoins and the TLS_DESC relocations.
Reloc_section* irelative_rel_;
// The .got.plt section.
- Output_data_space* got_plt_;
+ Output_data_got_plt_i386* got_plt_;
// The part of the .got.plt section used for IRELATIVE relocs.
Output_data_space* got_irelative_;
// The number of PLT entries.
{
public:
Output_data_plt_i386_standard(Layout* layout,
- Output_data_space* got_plt,
+ Output_data_got_plt_i386* got_plt,
Output_data_space* got_irelative)
: Output_data_plt_i386(layout, plt_entry_size, got_plt, got_irelative)
{ }
{
public:
Output_data_plt_i386_exec(Layout* layout,
- Output_data_space* got_plt,
+ Output_data_got_plt_i386* got_plt,
Output_data_space* got_irelative)
: Output_data_plt_i386_standard(layout, got_plt, got_irelative)
{ }
{
public:
Output_data_plt_i386_dyn(Layout* layout,
- Output_data_space* got_plt,
+ Output_data_got_plt_i386* got_plt,
Output_data_space* got_irelative)
: Output_data_plt_i386_standard(layout, got_plt, got_irelative)
{ }
: Sized_target<32, false>(info),
got_(NULL), plt_(NULL), got_plt_(NULL), got_irelative_(NULL),
got_tlsdesc_(NULL), global_offset_table_(NULL), rel_dyn_(NULL),
- rel_irelative_(NULL), copy_relocs_(elfcpp::R_386_COPY), dynbss_(NULL),
+ rel_irelative_(NULL), copy_relocs_(elfcpp::R_386_COPY),
got_mod_index_offset_(-1U), tls_base_symbol_defined_(false)
{ }
// This chooses the right PLT flavor for an executable or a shared object.
Output_data_plt_i386*
make_data_plt(Layout* layout,
- Output_data_space* got_plt,
+ Output_data_got_plt_i386* got_plt,
Output_data_space* got_irelative,
bool dyn)
{ return this->do_make_data_plt(layout, got_plt, got_irelative, dyn); }
virtual Output_data_plt_i386*
do_make_data_plt(Layout* layout,
- Output_data_space* got_plt,
+ Output_data_got_plt_i386* got_plt,
Output_data_space* got_irelative,
bool dyn)
{
static tls::Tls_optimization
optimize_tls_reloc(bool is_final, int r_type);
+ // Check if relocation against this symbol is a candidate for
+ // conversion from
+ // mov foo@GOT(%reg), %reg
+ // to
+ // lea foo@GOTOFF(%reg), %reg.
+ static bool
+ can_convert_mov_to_lea(const Symbol* gsym)
+ {
+ gold_assert(gsym != NULL);
+ return (gsym->type() != elfcpp::STT_GNU_IFUNC
+ && !gsym->is_undefined ()
+ && !gsym->is_from_dynobj()
+ && !gsym->is_preemptible()
+ && (!parameters->options().shared()
+ || (gsym->visibility() != elfcpp::STV_DEFAULT
+ && gsym->visibility() != elfcpp::STV_PROTECTED)
+ || parameters->options().Bsymbolic())
+ && strcmp(gsym->name(), "_DYNAMIC") != 0);
+ }
+
// Get the GOT section, creating it if necessary.
Output_data_got<32, false>*
got_section(Symbol_table*, Layout*);
// Get the GOT PLT section.
- Output_data_space*
+ Output_data_got_plt_i386*
got_plt_section() const
{
gold_assert(this->got_plt_ != NULL);
// The PLT section.
Output_data_plt_i386* plt_;
// The GOT PLT section.
- Output_data_space* got_plt_;
+ Output_data_got_plt_i386* got_plt_;
// The GOT section for IRELATIVE relocations.
Output_data_space* got_irelative_;
// The GOT section for TLSDESC relocations.
Reloc_section* rel_irelative_;
// Relocs saved to avoid a COPY reloc.
Copy_relocs<elfcpp::SHT_REL, 32, false> copy_relocs_;
- // Space for variables copied with a COPY reloc.
- Output_data_space* dynbss_;
// Offset of the GOT entry for the TLS module index.
unsigned int got_mod_index_offset_;
// True if the _TLS_MODULE_BASE_ symbol has been defined.
| elfcpp::SHF_WRITE),
this->got_, got_order, true);
- this->got_plt_ = new Output_data_space(4, "** GOT PLT");
+ this->got_plt_ = new Output_data_got_plt_i386(layout);
layout->add_output_section_data(".got.plt", elfcpp::SHT_PROGBITS,
(elfcpp::SHF_ALLOC
| elfcpp::SHF_WRITE),
return this->rel_irelative_;
}
+// Write the first three reserved words of the .got.plt section.
+// The remainder of the section is written while writing the PLT
+// in Output_data_plt_i386::do_write.
+
+void
+Output_data_got_plt_i386::do_write(Output_file* of)
+{
+ // 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_i386::got_section.
+ const off_t got_file_offset = this->offset();
+ gold_assert(this->data_size() >= 12);
+ unsigned char* const got_view = of->get_output_view(got_file_offset, 12);
+ Output_section* dynamic = this->layout_->dynamic_section();
+ uint32_t dynamic_addr = dynamic == NULL ? 0 : dynamic->address();
+ elfcpp::Swap<32, false>::writeval(got_view, dynamic_addr);
+ memset(got_view + 4, 0, 8);
+ of->write_output_view(got_file_offset, 12, got_view);
+}
+
// 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,
uint64_t addralign,
- Output_data_space* got_plt,
+ Output_data_got_plt_i386* got_plt,
Output_data_space* got_irelative)
: Output_section_data(addralign),
- layout_(layout), tls_desc_rel_(NULL),
- irelative_rel_(NULL), got_plt_(got_plt), got_irelative_(got_irelative),
- count_(0), irelative_count_(0), global_ifuncs_(), local_ifuncs_()
+ tls_desc_rel_(NULL), irelative_rel_(NULL), got_plt_(got_plt),
+ got_irelative_(got_irelative), count_(0), irelative_count_(0),
+ global_ifuncs_(), local_ifuncs_()
{
this->rel_ = new Reloc_section(false);
layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
const section_size_type got_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);
this->fill_first_plt_entry(pov, got_address);
pov += this->get_plt_entry_size();
- unsigned char* got_pov = got_view;
-
- // 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_i386::got_section.
- Output_section* dynamic = this->layout_->dynamic_section();
- uint32_t dynamic_addr = dynamic == NULL ? 0 : dynamic->address();
- elfcpp::Swap<32, false>::writeval(got_pov, dynamic_addr);
- got_pov += 4;
- memset(got_pov, 0, 8);
- got_pov += 8;
+ // The first three entries in the GOT are reserved, and are written
+ // by Output_data_got_plt_i386::do_write.
+ unsigned char* got_pov = got_view + 12;
const int rel_size = elfcpp::Elf_sizes<32>::rel_size;
case elfcpp::R_386_GOT32:
{
- // The symbol requires a GOT entry.
+ // We need GOT section.
Output_data_got<32, false>* got = target->got_section(symtab, layout);
+
+ // If the relocation symbol isn't IFUNC,
+ // and is local, then we will convert
+ // mov foo@GOT(%reg), %reg
+ // to
+ // lea foo@GOTOFF(%reg), %reg
+ // in Relocate::relocate.
+ if (reloc.get_r_offset() >= 2
+ && lsym.get_st_type() != elfcpp::STT_GNU_IFUNC)
+ {
+ section_size_type stype;
+ const unsigned char* view = object->section_contents(data_shndx,
+ &stype, true);
+ if (view[reloc.get_r_offset() - 2] == 0x8b)
+ break;
+ }
+
+ // Otherwise, the symbol requires a GOT entry.
unsigned int r_sym = elfcpp::elf_r_sym<32>(reloc.get_r_info());
// For a STT_GNU_IFUNC symbol we want the PLT offset. That
// Make a dynamic relocation if necessary.
if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
{
- if (gsym->may_need_copy_reloc())
+ if (!parameters->options().output_is_position_independent()
+ && gsym->may_need_copy_reloc())
{
target->copy_reloc(symtab, layout, object,
data_shndx, output_section, gsym, reloc);
// Make a dynamic relocation if necessary.
if (gsym->needs_dynamic_reloc(Scan::get_reference_flags(r_type)))
{
- if (gsym->may_need_copy_reloc())
+ if (parameters->options().output_is_executable()
+ && gsym->may_need_copy_reloc())
{
target->copy_reloc(symtab, layout, object,
data_shndx, output_section, gsym, reloc);
case elfcpp::R_386_GOT32:
{
- // The symbol requires a GOT entry.
+ // The symbol requires a GOT section.
Output_data_got<32, false>* got = target->got_section(symtab, layout);
+
+ // If we convert this from
+ // mov foo@GOT(%reg), %reg
+ // to
+ // lea foo@GOTOFF(%reg), %reg
+ // in Relocate::relocate, then there is nothing to do here.
+ if (reloc.get_r_offset() >= 2
+ && Target_i386::can_convert_mov_to_lea(gsym))
+ {
+ section_size_type stype;
+ const unsigned char* view = object->section_contents(data_shndx,
+ &stype, true);
+ if (view[reloc.get_r_offset() - 2] == 0x8b)
+ break;
+ }
+
if (gsym->final_value_is_known())
{
// For a STT_GNU_IFUNC symbol we want the PLT address.
}
}
- // Get the GOT offset if needed.
- // The GOT pointer points to the end of the GOT section.
- // We need to subtract the size of the GOT section to get
- // the actual offset to use in the relocation.
- bool have_got_offset = false;
- unsigned int got_offset = 0;
- switch (r_type)
- {
- case elfcpp::R_386_GOT32:
- if (gsym != NULL)
- {
- gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
- got_offset = (gsym->got_offset(GOT_TYPE_STANDARD)
- - 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_STANDARD));
- got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
- - target->got_size());
- }
- have_got_offset = true;
- break;
-
- default:
- break;
- }
-
switch (r_type)
{
case elfcpp::R_386_NONE:
break;
case elfcpp::R_386_GOT32:
- gold_assert(have_got_offset);
- Relocate_functions<32, false>::rel32(view, got_offset);
+ // Convert
+ // mov foo@GOT(%reg), %reg
+ // to
+ // lea foo@GOTOFF(%reg), %reg
+ // if possible.
+ if (rel.get_r_offset() >= 2
+ && view[-2] == 0x8b
+ && ((gsym == NULL && !psymval->is_ifunc_symbol())
+ || (gsym != NULL
+ && Target_i386::can_convert_mov_to_lea(gsym))))
+ {
+ view[-2] = 0x8d;
+ elfcpp::Elf_types<32>::Elf_Addr value;
+ value = (psymval->value(object, 0)
+ - target->got_plt_section()->address());
+ Relocate_functions<32, false>::rel32(view, value);
+ }
+ else
+ {
+ // The GOT pointer points to the end of the GOT section.
+ // We need to subtract the size of the GOT section to get
+ // the actual offset to use in the relocation.
+ unsigned int got_offset = 0;
+ if (gsym != NULL)
+ {
+ gold_assert(gsym->has_got_offset(GOT_TYPE_STANDARD));
+ got_offset = (gsym->got_offset(GOT_TYPE_STANDARD)
+ - 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_STANDARD));
+ got_offset = (object->local_got_offset(r_sym, GOT_TYPE_STANDARD)
+ - target->got_size());
+ }
+ Relocate_functions<32, false>::rel32(view, got_offset);
+ }
break;
case elfcpp::R_386_GOTOFF:
{
// leal foo(,%ebx,1),%eax; call ___tls_get_addr
// ==> movl %gs:0,%eax; addl foo@gotntpoff(%ebx),%eax
+ // leal foo(%ebx),%eax; call ___tls_get_addr; nop
+ // ==> movl %gs:0,%eax; addl foo@gotntpoff(%ebx),%eax
tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, -2);
tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 9);
op2 == 0x8d || op2 == 0x04);
tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[4] == 0xe8);
- int roff = 5;
-
- // FIXME: For now, support only the first (SIB) form.
- tls::check_tls(relinfo, relnum, rel.get_r_offset(), op2 == 0x04);
+ int roff;
if (op2 == 0x04)
{
tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[-3] == 0x8d);
tls::check_tls(relinfo, relnum, rel.get_r_offset(),
((op1 & 0xc7) == 0x05 && op1 != (4 << 3)));
- memcpy(view - 3, "\x65\xa1\0\0\0\0\x03\x83\0\0\0", 12);
+ roff = 5;
}
else
{
+ tls::check_range(relinfo, relnum, rel.get_r_offset(), view_size, 10);
tls::check_tls(relinfo, relnum, rel.get_r_offset(),
(op1 & 0xf8) == 0x80 && (op1 & 7) != 4);
- if (rel.get_r_offset() + 9 < view_size
- && view[9] == 0x90)
- {
- // FIXME: This is not the right instruction sequence.
- // There is a trailing nop. Use the size byte subl.
- memcpy(view - 2, "\x65\xa1\0\0\0\0\x81\xe8\0\0\0", 12);
- roff = 6;
- }
- else
- {
- // FIXME: This is not the right instruction sequence.
- // Use the five byte subl.
- memcpy(view - 2, "\x65\xa1\0\0\0\0\x2d\0\0\0", 11);
- }
+ tls::check_tls(relinfo, relnum, rel.get_r_offset(), view[9] == 0x90);
+ roff = 6;
}
+ memcpy(view + roff - 8, "\x65\xa1\0\0\0\0\x03\x83\0\0\0", 12);
Relocate_functions<32, false>::rel32(view + roff, value);
// The next reloc should be a PLT32 reloc against __tls_get_addr.
{
public:
Output_data_plt_i386_nacl(Layout* layout,
- Output_data_space* got_plt,
+ Output_data_got_plt_i386* got_plt,
Output_data_space* got_irelative)
: Output_data_plt_i386(layout, plt_entry_size, got_plt, got_irelative)
{ }
{
public:
Output_data_plt_i386_nacl_exec(Layout* layout,
- Output_data_space* got_plt,
+ Output_data_got_plt_i386* got_plt,
Output_data_space* got_irelative)
: Output_data_plt_i386_nacl(layout, got_plt, got_irelative)
{ }
{
public:
Output_data_plt_i386_nacl_dyn(Layout* layout,
- Output_data_space* got_plt,
+ Output_data_got_plt_i386* got_plt,
Output_data_space* got_irelative)
: Output_data_plt_i386_nacl(layout, got_plt, got_irelative)
{ }
protected:
virtual Output_data_plt_i386*
do_make_data_plt(Layout* layout,
- Output_data_space* got_plt,
+ Output_data_got_plt_i386* got_plt,
Output_data_space* got_irelative,
bool dyn)
{
return new Output_data_plt_i386_nacl_exec(layout, got_plt, got_irelative);
}
+ virtual std::string
+ do_code_fill(section_size_type length) const;
+
private:
static const Target::Target_info i386_nacl_info;
};
elfcpp::DW_CFA_nop
};
+// Return a string used to fill a code section with nops.
+// For NaCl, long NOPs are only valid if they do not cross
+// bundle alignment boundaries, so keep it simple with one-byte NOPs.
+std::string
+Target_i386_nacl::do_code_fill(section_size_type length) const
+{
+ return std::string(length, static_cast<char>(0x90));
+}
+
// The selector for i386-nacl object files.
class Target_selector_i386_nacl
projects / deliverable / binutils-gdb.git / blobdiff