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gold patch committed: Put IRELATIVE relocs after JUMP_SLOT relocs
- From: Ian Lance Taylor <iant at google dot com>
- To: binutils at sourceware dot org
- Date: Fri, 08 Jul 2011 15:50:02 -0700
- Subject: gold patch committed: Put IRELATIVE relocs after JUMP_SLOT relocs
PR 12372 points out a problem in gold: if an STT_GNU_IFUNC symbol is
defined with a function that calls other functions through the PLT, then
it is essential that the dynamic linker prepare the PLT entries before
it invokes the function for the STT_GNU_IFUNC symbol. The GNU linker
does this by simply putting all IRELATIVE relocs after all JUMP_SLOT
relocs. This patch implements the same approach in gold. Committed to
mainline.
Ian
2011-07-08 Ian Lance Taylor <iant@google.com>
PR gold/12372
* target.h (Target::plt_address_for_global): New function.
(Target::plt_address_for_local): New function.
(Target::plt_section_for_global): Remove.
(Target::plt_section_for_local): Remove.
(Target::do_plt_address_for_global): New virtual function.
(Target::do_plt_address_for_local): New virtual function.
(Target::do_plt_section_for_global): Remove.
(Target::do_plt_section_for_local): Remove.
(Target::register_global_plt_entry): Add Symbol_table and Layout
parameters.
* output.cc (Output_data_got::Got_entry::write): Use
plt_address_for_global and plt_address_for_local.
* layout.cc (Layout::add_target_dynamic_tags): Use size and
address of output section.
* i386.cc (class Output_data_plt_i386): Add irelative_rel_,
got_irelative_, and irelative_count_ fields. Update
declarations.
(Output_data_plt_i386::has_irelative_section): New function.
(Output_data_plt_i386::entry_count): Add irelative_count_.
(Output_data_plt_i386::set_final_data_size): Likewise.
(class Target_i386): Add got_irelative_ and rel_irelative_
fields. Update declarations.
(Target_i386::Target_i386): Initialize new fields.
(Target_i386::do_plt_address_for_global): New function replacing
do_plt_section_for_global.
(Target_i386::do_plt_address_for_local): New function replacing
do_plt_section_for_local.
(Target_i386::got_section): Create got_irelative_.
(Target_i386::rel_irelative_section): New function.
(Output_data_plt_i386::Output_data_plt_i386): Initialize new
fields. Don't define __rel_iplt_{start,end}.
(Output_data_plt_i386::add_entry): Add symtab and layout
parameters. Change all callers. Use different PLT and GOT for
IFUNC symbols.
(Output_data_plt_i386::add_local_ifunc_entry): Add symtab and
layout parameters. Change all callers. Use different PLT and
GOT.
(Output_data_plt_i386::rel_tls_desc): Fix formatting.
(Output_data_plt_i386::rel_irelative): New function.
(Output_data_plt_i386::address_for_global): New function.
(Output_data_plt_i386::address_for_local): New function.
(Output_data_plt_i386::do_write): Write out IRELATIVE area. Use
IRELATIVE GOT when changing IFUNC GOT entries.
(Target_i386::Scan::global): Use IRELATIVE GOT for IRELATIVE
reloc.
(Target_i386::do_finalize_sections): Create the __rel_iplt symbols
if we didn't create an IRELATIVE GOT.
(Target_i386::Relocate::relocate): Use plt_address_for_global and
plt_address_for_local.
(Target_i386::do_dynsym_value): Use plt_address_for_global.
* x86_64.cc (class Output_data_plt_x86_64): Add irelative_rel_,
got_irelative_, and irelative_count_ fields. Update
declarations.
(Output_data_plt_x86_64::Output_data_plt_x86_64) [both versions]:
Initialize new fields. Remove symtab parameter. Change all
callers.
(Output_data_plt_x86_64::get_tlsdesc_plt_offset): Add
irelative_count_.
(Output_data_plt_x86_64::has_irelative_section): New function.
(Output_data_plt_x86_64::entry_count): Add irelative_count_.
(class Target_x86_64): Add got_irelative_ and rel_irelative_
fields. Update declarations.
(Target_x86_64::Target_x86_64): Initialize new fields.
(Target_x86_64::do_plt_address_for_global): New function replacing
do_plt_section_for_global.
(Target_x86_64::do_plt_address_for_local): New function replacing
do_plt_section_for_local.
(Target_x86_64::got_section): Create got_irelative_.
(Target_x86_64::rela_irelative_section): New function.
(Output_data_plt_x86_64::init): Remove symtab parameter. Change
all callers. Don't create __rel_iplt_{start,end}.
(Output_data_plt_x86_64::add_entry): Add symtab and layout
parameters. Change all callers. Use different PLT and GOT for
IFUNC symbols.
(Output_data_plt_x86_64::add_local_ifunc_entry): Add symtab and
layout parameters. Change all callers. Use different PLT and
GOT.
(Output_data_plt_x86_64::add_relocation): Add symtab and layout
parameters. Change all callers. Use different PLT and GOT for
IFUNC symbols.
(Output_data_plt_x86_64::rela_tlsdesc): Fix formatting.
(Output_data_plt_x86_64::rela_irelative): New function.
(Output_data_plt_x86_64::address_for_global): New function.
(Output_data_plt_x86_64::address_for_local): New function.
(Output_data_plt_x86_64::set_final_data_size): Likewise.
(Output_data_plt_x86_64::do_write): Write out IRELATIVE area.
(Target_x86_64::init_got_plt_for_update): Create got_irelative_.
(Target_x86_64::register_global_plt_entry): Add symtab and layout
parameters.
(Target_x86_64::Scan::global): Use IRELATIVE GOT for IRELATIVE
reloc.
(Target_x86_64::do_finalize_sections): Create the __rela_iplt
symbols if we didn't create an IRELATIVE GOT.
(Target_x86_64::Relocate::relocate): Use plt_address_for_global and
plt_address_for_local.
(Target_x86_64::do_dynsym_value): Use plt_address_for_global.
* testsuite/ifuncvar1.c: New test file.
* testsuite/ifuncvar2.c: New test file.
* testsuite/ifuncvar3.c: New test file.
* testsuite/Makefile.am (check_PROGRAMS): Add ifuncvar.
(ifuncvar1_pic.o, ifuncvar2_pic.o, ifuncvar.so): New targets.
(ifuncvar_SOURCES, ifuncvar_DEPENDENCIES): New variables.
(ifuncvar_LDFLAGS, ifuncvar_LDADD): New variables.
* testsuite/Makefile.in: Rebuild.
Index: i386.cc
===================================================================
RCS file: /cvs/src/src/gold/i386.cc,v
retrieving revision 1.135
diff -u -p -r1.135 i386.cc
--- i386.cc 6 Jul 2011 05:12:03 -0000 1.135
+++ i386.cc 8 Jul 2011 22:33:21 -0000
@@ -53,15 +53,16 @@ class Output_data_plt_i386 : public Outp
public:
typedef Output_data_reloc<elfcpp::SHT_REL, true, 32, false> Reloc_section;
- Output_data_plt_i386(Symbol_table*, Layout*, Output_data_space*);
+ Output_data_plt_i386(Layout*, Output_data_space*, Output_data_space*);
// 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<32, false>* relobj,
+ add_local_ifunc_entry(Symbol_table*, Layout*,
+ Sized_relobj_file<32, false>* relobj,
unsigned int local_sym_index);
// Return the .rel.plt section data.
@@ -73,10 +74,19 @@ class Output_data_plt_i386 : public Outp
Reloc_section*
rel_tls_desc(Layout*);
+ // Return where the IRELATIVE relocations should go.
+ Reloc_section*
+ rel_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
@@ -88,6 +98,14 @@ class Output_data_plt_i386 : public Outp
get_plt_entry_size()
{ return 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);
@@ -122,7 +140,10 @@ class Output_data_plt_i386 : public Outp
// Set the final size.
void
set_final_data_size()
- { this->set_data_size((this->count_ + 1) * plt_entry_size); }
+ {
+ this->set_data_size((this->count_ + this->irelative_count_ + 1)
+ * plt_entry_size);
+ }
// Write out the PLT data.
void
@@ -150,10 +171,18 @@ class Output_data_plt_i386 : public Outp
// The TLS_DESC relocations, if necessary. These must follow the
// regular PLT relocs.
Reloc_section* tls_desc_rel_;
+ // The IRELATIVE 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_;
+ // 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_386_IRELATIVE relocs. These follow
+ // the regular PLT entries.
+ unsigned int irelative_count_;
// Global STT_GNU_IFUNC symbols.
std::vector<Global_ifunc> global_ifuncs_;
// Local STT_GNU_IFUNC symbols.
@@ -172,9 +201,9 @@ class Target_i386 : public Sized_target<
Target_i386()
: 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_(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),
got_mod_index_offset_(-1U), tls_base_symbol_defined_(false)
{ }
@@ -281,14 +310,14 @@ class Target_i386 : public Sized_target<
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(); }
+ // Return the PLT address to use for a global symbol.
+ 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); }
// We can tell whether we take the address of a function.
inline bool
@@ -589,6 +618,10 @@ class Target_i386 : public Sized_target<
Reloc_section*
rel_tls_desc_section(Layout*) const;
+ // Get the section to use for IRELATIVE relocations.
+ Reloc_section*
+ rel_irelative_section(Layout*);
+
// Add a potential copy relocation.
void
copy_reloc(Symbol_table* symtab, Layout* layout,
@@ -625,12 +658,16 @@ class Target_i386 : public Sized_target<
Output_data_plt_i386* 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<32, false>* got_tlsdesc_;
// The _GLOBAL_OFFSET_TABLE_ symbol.
Symbol* global_offset_table_;
// The dynamic reloc section.
Reloc_section* rel_dyn_;
+ // The section to use for IRELATIVE relocs.
+ 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.
@@ -703,6 +740,15 @@ Target_i386::got_section(Symbol_table* s
elfcpp::STV_HIDDEN, 0,
false, false);
+ // If there are any IRELATIVE relocations, they get GOT entries
+ // in .got.plt after the jump slot relocations.
+ this->got_irelative_ = new Output_data_space(4, "** 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);
+
// 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>();
@@ -732,39 +778,45 @@ Target_i386::rel_dyn_section(Layout* lay
return this->rel_dyn_;
}
+// Get the section to use for IRELATIVE relocs, creating it if
+// necessary. These go in .rel.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_i386::Reloc_section*
+Target_i386::rel_irelative_section(Layout* layout)
+{
+ if (this->rel_irelative_ == NULL)
+ {
+ // Make sure we have already create the dynamic reloc section.
+ this->rel_dyn_section(layout);
+ this->rel_irelative_ = new Reloc_section(false);
+ layout->add_output_section_data(".rel.dyn", elfcpp::SHT_REL,
+ elfcpp::SHF_ALLOC, this->rel_irelative_,
+ ORDER_DYNAMIC_RELOCS, false);
+ gold_assert(this->rel_dyn_->output_section()
+ == this->rel_irelative_->output_section());
+ }
+ return this->rel_irelative_;
+}
+
// 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(Symbol_table* symtab,
- Layout* layout,
- Output_data_space* got_plt)
- : Output_section_data(16), tls_desc_rel_(NULL), got_plt_(got_plt), count_(0),
- global_ifuncs_(), local_ifuncs_()
+Output_data_plt_i386::Output_data_plt_i386(Layout* layout,
+ Output_data_space* got_plt,
+ Output_data_space* got_irelative)
+ : Output_section_data(16), 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,
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,
@@ -782,29 +834,23 @@ Output_data_plt_i386::do_adjust_output_s
// Add an entry to the PLT.
void
-Output_data_plt_i386::add_entry(Symbol* gsym)
+Output_data_plt_i386::add_entry(Symbol_table* symtab, Layout* layout,
+ Symbol* gsym)
{
gold_assert(!gsym->has_plt_offset());
- // Note that when setting the PLT offset we skip the initial
- // reserved PLT entry.
- gsym->set_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 will be changed by the dynamic linker, normally
- // lazily when the function is called).
- this->got_plt_->set_current_data_size(got_offset + 4);
-
// Every PLT entry needs a reloc.
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);
+ gsym->set_plt_offset(this->irelative_count_ * plt_entry_size);
+ ++this->irelative_count_;
+ section_offset_type got_offset =
+ this->got_irelative_->current_data_size();
+ this->got_irelative_->set_current_data_size(got_offset + 4);
+ Reloc_section* rel = this->rel_irelative(symtab, layout);
+ rel->add_symbolless_global_addend(gsym, elfcpp::R_386_IRELATIVE,
+ this->got_irelative_, got_offset);
struct Global_ifunc gi;
gi.sym = gsym;
gi.got_offset = got_offset;
@@ -812,6 +858,19 @@ Output_data_plt_i386::add_entry(Symbol*
}
else
{
+ // When setting the PLT offset we skip the initial reserved PLT
+ // entry.
+ gsym->set_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 will be changed by the dynamic linker,
+ // normally lazily when the function is called).
+ this->got_plt_->set_current_data_size(got_offset + 4);
+
gsym->set_needs_dynsym_entry();
this->rel_->add_global(gsym, elfcpp::R_386_JUMP_SLOT, this->got_plt_,
got_offset);
@@ -827,22 +886,25 @@ Output_data_plt_i386::add_entry(Symbol*
unsigned int
Output_data_plt_i386::add_local_ifunc_entry(
+ Symbol_table* symtab,
+ Layout* layout,
Sized_relobj_file<32, 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 + 4);
+ this->got_irelative_->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);
+ Reloc_section* rel = this->rel_irelative(symtab, layout);
+ rel->add_symbolless_local_addend(relobj, local_sym_index,
+ elfcpp::R_386_IRELATIVE,
+ this->got_irelative_, got_offset);
struct Local_ifunc li;
li.object = relobj;
@@ -865,12 +927,72 @@ Output_data_plt_i386::rel_tls_desc(Layou
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());
+ gold_assert(this->tls_desc_rel_->output_section()
+ == this->rel_->output_section());
}
return this->tls_desc_rel_;
}
+// Return where the IRELATIVE relocations should go in the PLT. These
+// follow the JUMP_SLOT and TLS_DESC relocations.
+
+Output_data_plt_i386::Reloc_section*
+Output_data_plt_i386::rel_irelative(Symbol_table* symtab, Layout* layout)
+{
+ if (this->irelative_rel_ == NULL)
+ {
+ // Make sure we have a place for the TLS_DESC relocations, in
+ // case we see any later on.
+ this->rel_tls_desc(layout);
+ this->irelative_rel_ = new Reloc_section(false);
+ layout->add_output_section_data(".rel.plt", elfcpp::SHT_REL,
+ 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 .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->irelative_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->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_i386::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_i386::address_for_local(const Relobj*, unsigned int)
+{
+ return this->address() + (this->count_ + 1) * plt_entry_size;
+}
+
// The first entry in the PLT for an executable.
const unsigned char Output_data_plt_i386::exec_first_plt_entry[plt_entry_size] =
@@ -976,8 +1098,12 @@ Output_data_plt_i386::do_write(Output_fi
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);
@@ -1006,7 +1132,7 @@ Output_data_plt_i386::do_write(Output_fi
unsigned int plt_offset = plt_entry_size;
unsigned int plt_rel_offset = 0;
unsigned int got_offset = 12;
- const unsigned int count = this->count_;
+ const unsigned int count = this->count_ + this->irelative_count_;
for (unsigned int i = 0;
i < count;
++i,
@@ -1043,6 +1169,7 @@ Output_data_plt_i386::do_write(Output_fi
// 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.
+ unsigned char* got_irelative_view = got_view + this->got_plt_->data_size();
for (std::vector<Global_ifunc>::const_iterator p =
this->global_ifuncs_.begin();
p != this->global_ifuncs_.end();
@@ -1050,7 +1177,7 @@ Output_data_plt_i386::do_write(Output_fi
{
const Sized_symbol<32>* ssym =
static_cast<const Sized_symbol<32>*>(p->sym);
- elfcpp::Swap<32, false>::writeval(got_view + p->got_offset,
+ elfcpp::Swap<32, false>::writeval(got_irelative_view + p->got_offset,
ssym->value());
}
@@ -1061,7 +1188,7 @@ Output_data_plt_i386::do_write(Output_fi
{
const Symbol_value<32>* psymval =
p->object->local_symbol(p->local_sym_index);
- elfcpp::Swap<32, false>::writeval(got_view + p->got_offset,
+ elfcpp::Swap<32, false>::writeval(got_irelative_view + p->got_offset,
psymval->value(p->object, 0));
}
@@ -1082,7 +1209,8 @@ Target_i386::make_plt_section(Symbol_tab
// Create the GOT sections first.
this->got_section(symtab, layout);
- this->plt_ = new Output_data_plt_i386(symtab, layout, this->got_plt_);
+ this->plt_ = new Output_data_plt_i386(layout, this->got_plt_,
+ this->got_irelative_);
layout->add_output_section_data(".plt", elfcpp::SHT_PROGBITS,
(elfcpp::SHF_ALLOC
| elfcpp::SHF_EXECINSTR),
@@ -1103,7 +1231,7 @@ Target_i386::make_plt_entry(Symbol_table
return;
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.
@@ -1117,7 +1245,8 @@ Target_i386::make_local_ifunc_plt_entry(
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);
}
@@ -1779,7 +1908,7 @@ Target_i386::Scan::global(Symbol_table*
// 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);
+ Reloc_section* rel_dyn = target->rel_irelative_section(layout);
rel_dyn->add_symbolless_global_addend(gsym,
elfcpp::R_386_IRELATIVE,
output_section,
@@ -2182,7 +2311,8 @@ Target_i386::do_finalize_sections(
symtab->get_sized_symbol<32>(sym)->set_symsize(data_size);
}
- if (parameters->doing_static_link() && this->plt_ == NULL)
+ if (parameters->doing_static_link()
+ && (this->plt_ == NULL || !this->plt_->has_irelative_section()))
{
// If linking statically, make sure that the __rel_iplt symbols
// were defined if necessary, even if we didn't create a PLT.
@@ -2312,7 +2442,7 @@ Target_i386::Relocate::relocate(const Re
else 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;
}
@@ -2321,7 +2451,7 @@ Target_i386::Relocate::relocate(const Re
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()
+ symval.set_output_value(target->plt_address_for_local(object, r_sym)
+ object->local_plt_offset(r_sym));
psymval = &symval;
}
@@ -3245,7 +3375,7 @@ uint64_t
Target_i386::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
Index: incremental.cc
===================================================================
RCS file: /cvs/src/src/gold/incremental.cc,v
retrieving revision 1.43
diff -u -p -r1.43 incremental.cc
--- incremental.cc 6 Jul 2011 22:26:37 -0000 1.43
+++ incremental.cc 8 Jul 2011 22:33:21 -0000
@@ -1,6 +1,6 @@
// inremental.cc -- incremental linking support for gold
-// Copyright 2009, 2010 Free Software Foundation, Inc.
+// Copyright 2009, 2010, 2011 Free Software Foundation, Inc.
// Written by Mikolaj Zalewski <mikolajz@google.com>.
// This file is part of gold.
@@ -674,7 +674,7 @@ Sized_incremental_binary<size, big_endia
gold_debug(DEBUG_INCREMENTAL,
"PLT entry %d: %s",
i, sym->name());
- target->register_global_plt_entry(i, sym);
+ target->register_global_plt_entry(symtab, layout, i, sym);
}
}
}
Index: layout.cc
===================================================================
RCS file: /cvs/src/src/gold/layout.cc,v
retrieving revision 1.212
diff -u -p -r1.212 layout.cc
--- layout.cc 6 Jul 2011 21:19:31 -0000 1.212
+++ layout.cc 8 Jul 2011 22:33:21 -0000
@@ -4027,7 +4027,8 @@ Layout::create_interp(const Target* targ
// some targets have multiple reloc sections in PLT_REL.
// If DYN_REL is not NULL, it is used for DT_REL/DT_RELA,
-// DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT.
+// DT_RELSZ/DT_RELASZ, DT_RELENT/DT_RELAENT. Again we use the output
+// section.
// If ADD_DEBUG is true, we add a DT_DEBUG entry when generating an
// executable.
@@ -4056,13 +4057,16 @@ Layout::add_target_dynamic_tags(bool use
if (dyn_rel != NULL && dyn_rel->output_section() != NULL)
{
odyn->add_section_address(use_rel ? elfcpp::DT_REL : elfcpp::DT_RELA,
- dyn_rel);
- if (plt_rel != NULL && dynrel_includes_plt)
+ dyn_rel->output_section());
+ if (plt_rel != NULL
+ && plt_rel->output_section() != NULL
+ && dynrel_includes_plt)
odyn->add_section_size(use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ,
- dyn_rel, plt_rel);
+ dyn_rel->output_section(),
+ plt_rel->output_section());
else
odyn->add_section_size(use_rel ? elfcpp::DT_RELSZ : elfcpp::DT_RELASZ,
- dyn_rel);
+ dyn_rel->output_section());
const int size = parameters->target().get_size();
elfcpp::DT rel_tag;
int rel_size;
Index: output.cc
===================================================================
RCS file: /cvs/src/src/gold/output.cc,v
retrieving revision 1.154
diff -u -p -r1.154 output.cc
--- output.cc 6 Jul 2011 21:19:32 -0000 1.154
+++ output.cc 8 Jul 2011 22:33:21 -0000
@@ -1347,7 +1347,7 @@ Output_data_got<size, big_endian>::Got_e
// RELATIVE relocation.
Symbol* gsym = this->u_.gsym;
if (this->use_plt_offset_ && gsym->has_plt_offset())
- val = (parameters->target().plt_section_for_global(gsym)->address()
+ val = (parameters->target().plt_address_for_global(gsym)
+ gsym->plt_offset());
else
{
@@ -1381,9 +1381,9 @@ Output_data_got<size, big_endian>::Got_e
val = symval->value(this->u_.object, 0);
else
{
- const Output_data* plt =
- parameters->target().plt_section_for_local(object, lsi);
- val = plt->address() + object->local_plt_offset(lsi);
+ uint64_t plt_address =
+ parameters->target().plt_address_for_local(object, lsi);
+ val = plt_address + object->local_plt_offset(lsi);
}
}
break;
Index: target.h
===================================================================
RCS file: /cvs/src/src/gold/target.h,v
retrieving revision 1.61
diff -u -p -r1.61 target.h
--- target.h 2 Jul 2011 00:03:25 -0000 1.61
+++ target.h 8 Jul 2011 22:33:21 -0000
@@ -246,17 +246,19 @@ class Target
reloc_addend(void* arg, unsigned int type, uint64_t addend) const
{ return this->do_reloc_addend(arg, type, addend); }
- // Return the PLT section to use for a global symbol. This is used
- // for STT_GNU_IFUNC symbols.
- Output_data*
- plt_section_for_global(const Symbol* sym) const
- { return this->do_plt_section_for_global(sym); }
-
- // Return the PLT section to use for a local symbol. This is used
- // for STT_GNU_IFUNC symbols.
- Output_data*
- plt_section_for_local(const Relobj* object, unsigned int symndx) const
- { return this->do_plt_section_for_local(object, symndx); }
+ // Return the PLT address to use for a global symbol. This is used
+ // for STT_GNU_IFUNC symbols. The symbol's plt_offset is relative
+ // to this PLT address.
+ uint64_t
+ plt_address_for_global(const Symbol* sym) const
+ { return this->do_plt_address_for_global(sym); }
+
+ // Return the PLT address to use for a local symbol. This is used
+ // for STT_GNU_IFUNC symbols. The symbol's plt_offset is relative
+ // to this PLT address.
+ uint64_t
+ plt_address_for_local(const Relobj* object, unsigned int symndx) const
+ { return this->do_plt_address_for_local(object, symndx); }
// Return whether this target can use relocation types to determine
// if a function's address is taken.
@@ -502,12 +504,12 @@ class Target
// Virtual functions that must be overridden by a target that uses
// STT_GNU_IFUNC symbols.
- virtual Output_data*
- do_plt_section_for_global(const Symbol*) const
+ virtual uint64_t
+ do_plt_address_for_global(const Symbol*) const
{ gold_unreachable(); }
- virtual Output_data*
- do_plt_section_for_local(const Relobj*, unsigned int) const
+ virtual uint64_t
+ do_plt_address_for_local(const Relobj*, unsigned int) const
{ gold_unreachable(); }
// Virtual function which may be overriden by the child class.
@@ -870,7 +872,8 @@ class Sized_target : public Target
// A target needs to implement this to support incremental linking.
virtual void
- register_global_plt_entry(unsigned int /* plt_index */,
+ register_global_plt_entry(Symbol_table*, Layout*,
+ unsigned int /* plt_index */,
Symbol*)
{ gold_unreachable(); }
Index: x86_64.cc
===================================================================
RCS file: /cvs/src/src/gold/x86_64.cc,v
retrieving revision 1.133
diff -u -p -r1.133 x86_64.cc
--- x86_64.cc 6 Jul 2011 05:12:03 -0000 1.133
+++ x86_64.cc 8 Jul 2011 22:33:21 -0000
@@ -54,22 +54,24 @@ class Output_data_plt_x86_64 : public Ou
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(16), 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(Layout* layout, Output_data_got<64, false>* got,
+ Output_data_space* got_plt,
+ Output_data_space* got_irelative)
+ : Output_section_data(16), 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(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,
unsigned int plt_count)
: Output_section_data((plt_count + 1) * plt_entry_size, 16, false),
- tlsdesc_rel_(NULL), got_(got), got_plt_(got_plt),
- count_(plt_count), tlsdesc_got_offset_(-1U), free_list_()
+ 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);
@@ -78,20 +80,22 @@ class Output_data_plt_x86_64 : public Ou
// 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
@@ -111,7 +115,7 @@ class Output_data_plt_x86_64 : public Ou
// 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*
@@ -122,10 +126,20 @@ class Output_data_plt_x86_64 : public Ou
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
@@ -145,6 +159,14 @@ class Output_data_plt_x86_64 : public Ou
(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);
@@ -188,12 +210,20 @@ class Output_data_plt_x86_64 : public Ou
// 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
@@ -217,10 +247,10 @@ class Target_x86_64 : public Sized_targe
Target_x86_64()
: Sized_target<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_(),
+ 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)
{ }
@@ -332,13 +362,13 @@ class Target_x86_64 : public Sized_targe
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(); }
-
- Output_data*
- do_plt_section_for_local(const Relobj*, unsigned int) 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
@@ -413,7 +443,8 @@ class Target_x86_64 : public Sized_targe
// 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
@@ -683,6 +714,10 @@ class Target_x86_64 : public Sized_targe
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,
@@ -733,12 +768,16 @@ class Target_x86_64 : public Sized_targe
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.
@@ -826,8 +865,17 @@ Target_x86_64::got_section(Symbol_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_,
+ ORDER_NON_RELRO_FIRST, false);
+
// 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
@@ -855,34 +903,39 @@ Target_x86_64::rela_dyn_section(Layout*
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,
@@ -898,7 +951,8 @@ Output_data_plt_x86_64::do_adjust_output
// 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());
@@ -906,25 +960,47 @@ Output_data_plt_x86_64::add_entry(Symbol
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)
@@ -935,13 +1011,13 @@ Output_data_plt_x86_64::add_entry(Symbol
// 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
@@ -953,22 +1029,25 @@ Output_data_plt_x86_64::add_entry(Symbol
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;
}
@@ -976,12 +1055,16 @@ Output_data_plt_x86_64::add_local_ifunc_
// 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();
@@ -1002,17 +1085,78 @@ Output_data_plt_x86_64::rela_tlsdesc(Lay
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);
@@ -1117,8 +1261,12 @@ Output_data_plt_x86_64::do_write(Output_
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);
@@ -1150,7 +1298,7 @@ Output_data_plt_x86_64::do_write(Output_
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,
@@ -1208,8 +1356,9 @@ Target_x86_64::make_plt_section(Symbol_t
// 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),
@@ -1241,7 +1390,7 @@ Target_x86_64::make_plt_entry(Symbol_tab
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.
@@ -1255,7 +1404,8 @@ Target_x86_64::make_local_ifunc_plt_entr
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);
}
@@ -1330,9 +1480,17 @@ Target_x86_64::init_got_plt_for_update(S
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);
@@ -1439,7 +1597,9 @@ Target_x86_64::reserve_global_got_entry(
// 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);
@@ -1450,7 +1610,7 @@ Target_x86_64::register_global_plt_entry
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.
@@ -2196,7 +2356,8 @@ Target_x86_64::Scan::global(Symbol_table
// 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,
@@ -2600,7 +2761,8 @@ Target_x86_64::do_finalize_sections(
symtab->get_sized_symbol<64>(sym)->set_symsize(data_size);
}
- if (parameters->doing_static_link() && this->plt_ == NULL)
+ 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.
@@ -2680,7 +2842,7 @@ Target_x86_64::Relocate::relocate(const
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;
}
@@ -2689,7 +2851,7 @@ Target_x86_64::Relocate::relocate(const
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;
}
@@ -3599,7 +3761,7 @@ uint64_t
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
Index: testsuite/Makefile.am
===================================================================
RCS file: /cvs/src/src/gold/testsuite/Makefile.am,v
retrieving revision 1.175
diff -u -p -r1.175 Makefile.am
--- testsuite/Makefile.am 7 Jul 2011 18:41:53 -0000 1.175
+++ testsuite/Makefile.am 8 Jul 2011 22:33:22 -0000
@@ -1833,6 +1833,18 @@ check_PROGRAMS += ifuncmain7pie
ifuncmain7pie: ifuncmain7pie.o gcctestdir/ld
$(LINK) -Bgcctestdir/ -pie ifuncmain7pie.o
+check_PROGRAMS += ifuncvar
+ifuncvar1_pic.o: ifuncvar1.c
+ $(COMPILE) -c -fpic -o $@ $<
+ifuncvar2_pic.o: ifuncvar2.c
+ $(COMPILE) -c -fpic -o $@ $<
+ifuncvar.so: ifuncvar1_pic.o ifuncvar2_pic.o gcctestdir/ld
+ $(LINK) -Bgcctestdir/ -shared ifuncvar1_pic.o ifuncvar2_pic.o
+ifuncvar_SOURCES = ifuncvar3.c
+ifuncvar_DEPENDENCIES = gcctestdir/ld ifuncvar.so
+ifuncvar_LDFLAGS = -Bgcctestdir/ -Wl,-R,.
+ifuncvar_LDADD = ifuncvar.so
+
endif IFUNC
# Test that strong reference to a weak symbol in a DSO remains strong.
Index: testsuite/ifuncvar1.c
===================================================================
RCS file: testsuite/ifuncvar1.c
diff -N testsuite/ifuncvar1.c
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ testsuite/ifuncvar1.c 8 Jul 2011 22:33:22 -0000
@@ -0,0 +1,20 @@
+/* Test global variable initialized to hidden STT_GNU_IFUNC symbol. */
+
+int didit;
+
+extern void doit (void);
+
+void
+doit (void)
+{
+ didit = 1;
+}
+
+void (*get_foo (void)) (void) __asm__ ("foo");
+__asm__ (".type foo, %gnu_indirect_function");
+__asm__ (".hidden foo");
+
+void (*get_foo (void)) (void)
+{
+ return &doit;
+}
Index: testsuite/ifuncvar2.c
===================================================================
RCS file: testsuite/ifuncvar2.c
diff -N testsuite/ifuncvar2.c
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ testsuite/ifuncvar2.c 8 Jul 2011 22:33:22 -0000
@@ -0,0 +1,12 @@
+/* Test global variable initialized to hidden STT_GNU_IFUNC symbol. */
+
+extern void foo (void);
+void (*f) (void) = &foo;
+
+extern void bar (void);
+
+void
+bar (void)
+{
+ f ();
+}
Index: testsuite/ifuncvar3.c
===================================================================
RCS file: testsuite/ifuncvar3.c
diff -N testsuite/ifuncvar3.c
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ testsuite/ifuncvar3.c 8 Jul 2011 22:33:22 -0000
@@ -0,0 +1,14 @@
+/* Test global variable initialized to hidden STT_GNU_IFUNC symbol. */
+
+#include <assert.h>
+
+extern void bar (void);
+extern int didit;
+
+int
+main (void)
+{
+ bar ();
+ assert (didit == 1);
+ return 0;
+}