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[GOLD] PowerPC tls_get_addr_optimize

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This implements the special __tls_get_addr_opt call stub for powerpc
gold that returns __thread variable addresses without actually making
a call to __tls_get_addr in most cases.  Shared libraries that are
loaded at program load time (ie. dlopen is not used) have a known
layout for their __thread variables, and thus DTPMOD64/DPTREL64 pairs
describing those variables can be set up by ld.so for the
__tls_get_addr_opt call stub fast exit.
Ref https://sourceware.org/ml/libc-alpha/2015-03/msg00626.html

I really, really wish I'd used a differently versioned __tls_get_addr
symbol than the base symbol to indicate glibc support for the
optimized call, rather than having glibc export __tls_get_addr_opt.  A
lot of the messing around here, flipping symbols from __tls_get_addr
to __tls_get_addr_opt, is caused by that decision.  About the only
benefit is that a user can see at a glance that their disassembled
code is calling __tls_get_addr via the fancy call stub..  Anyway, we
need references to __tls_get_addr to seem like they were to
__tls_get_addr_opt, and in cases like the tsan interceptor, a
definition of __tls_get_addr to seem like one of __tls_get_addr_opt
as well.  That's the reason for Symbol::clear_in_reg and
Symbol_table::clone, and why symbols are substituted in Scan::global
and other places dealing with dynamic linking.

elfcpp/
	* elfcpp.h (DT_PPC_OPT): Define.
	* powerpc.h (PPC_OPT_TLS): Define.
gold/
	* options.h (tls_get_addr_optimize): New option.
	* symtab.h (Symbol::clear_in_reg, clone): New functions.
	(Sized_symbol::clone): New function.
	(Symbol_table::clone): New function.
	* resolve.cc (Symbol::clone, Sized_symbol::clone): New functions.
	* powerpc.cc (Target_powerpc::has_tls_get_addr_opt_,
	tls_get_addr_, tls_get_addr_opt_): New vars.
	(Target_powerpc::tls_get_addr_opt, tls_get_addr,
	is_tls_get_addr_opt, replace_tls_get_addr,
	set_has_tls_get_addr_opt, stk_linker): New functions.
	(Target_powerpc::Track_tls::maybe_skip_tls_get_addr_call): Add
	target param.  Update callers.  Compare symbols rather than names.
	(Target_powerpc::do_define_standard_symbols): Init tls_get_addr_
	and tls_get_addr_opt_.
	(Target_powerpc::Branch_info::mark_pltcall): Translate tls_get_addr
	sym to tls_get_addr_opt.
	(Target_powerpc::Branch_info::make_stub): Likewise.
	(Stub_table::define_stub_syms): Likewise.
	(Target_powerpc::Scan::global): Likewise.
	(Target_powerpc::Relocate::relocate): Likewise.
	(add_3_12_2, add_3_12_13, bctrl, beqlr, cmpdi_11_0, cmpwi_11_0,
	ld_11_1, ld_11_3, ld_12_3, lwz_11_3, lwz_12_3, mr_0_3, mr_3_0,
	mtlr_11, std_11_1): New constants.
	(Stub_table::eh_frame_added_): Delete.
	(Stub_table::tls_get_addr_opt_bctrl_, plt_fde_len_, plt_fde_): New vars.
	(Stub_table::init_plt_fde): New functions.
	(Stub_table::add_eh_frame, replace_eh_frame): Move definition out
	of line.  Init and use plt_fde_.
	(Stub_table::plt_call_size): Return size for tls_get_addr stub.
	Extract alignment code to..
	(Stub_table::plt_call_align): ..this new function.  Adjust all callers.
	(Stub_table::add_plt_call_entry): Set has_tls_get_addr_opt and
	tls_get_addr_opt_bctrl, and align after that.
	(Stub_table::do_write): Write out tls_get_addr stub.
	(Target_powerpc::do_finalize_sections): Emit DT_PPC_OPT
	PPC_OPT_TLS/PPC64_OPT_TLS bit.
	(Target_powerpc::Relocate::relocate): Don't check for or modify
	nop following bl for tls_get_addr stub.
This commit is contained in:
Alan Modra 2017-08-29 15:55:33 +09:30
parent 34ca2bd7ac
commit 34e0882b83
8 changed files with 455 additions and 58 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
elfcpp/ChangeLog
View File

@ -1,3 +1,8 @@
2017-08-29 Alan Modra <amodra@gmail.com>
* elfcpp.h (DT_PPC_OPT): Define.
* powerpc.h (PPC_OPT_TLS): Define.
2017-07-28 H.J. Lu <hongjiu.lu@intel.com>
PR gold/21857

3
elfcpp/elfcpp.h
View File

@ -768,6 +768,9 @@ enum DT
// Specify the value of _GLOBAL_OFFSET_TABLE_.
DT_PPC_GOT = 0x70000000,
// Specify whether various optimisations are possible.
DT_PPC_OPT = 0x70000001,
// Specify the start of the .glink section.
DT_PPC64_GLINK = 0x70000000,

6
elfcpp/powerpc.h
View File

@ -228,6 +228,12 @@ enum
EF_PPC64_ABI = 3
};
// DT_PPC_OPT bits
enum
{
PPC_OPT_TLS = 1
};
// DT_PPC64_OPT bits
enum
{

41
gold/ChangeLog
View File

@ -1,3 +1,44 @@
2017-08-29 Alan Modra <amodra@gmail.com>
* options.h (tls_get_addr_optimize): New option.
* symtab.h (Symbol::clear_in_reg, clone): New functions.
(Sized_symbol::clone): New function.
(Symbol_table::clone): New function.
* resolve.cc (Symbol::clone, Sized_symbol::clone): New functions.
* powerpc.cc (Target_powerpc::has_tls_get_addr_opt_,
tls_get_addr_, tls_get_addr_opt_): New vars.
(Target_powerpc::tls_get_addr_opt, tls_get_addr,
is_tls_get_addr_opt, replace_tls_get_addr,
set_has_tls_get_addr_opt, stk_linker): New functions.
(Target_powerpc::Track_tls::maybe_skip_tls_get_addr_call): Add
target param. Update callers. Compare symbols rather than names.
(Target_powerpc::do_define_standard_symbols): Init tls_get_addr_
and tls_get_addr_opt_.
(Target_powerpc::Branch_info::mark_pltcall): Translate tls_get_addr
sym to tls_get_addr_opt.
(Target_powerpc::Branch_info::make_stub): Likewise.
(Stub_table::define_stub_syms): Likewise.
(Target_powerpc::Scan::global): Likewise.
(Target_powerpc::Relocate::relocate): Likewise.
(add_3_12_2, add_3_12_13, bctrl, beqlr, cmpdi_11_0, cmpwi_11_0,
ld_11_1, ld_11_3, ld_12_3, lwz_11_3, lwz_12_3, mr_0_3, mr_3_0,
mtlr_11, std_11_1): New constants.
(Stub_table::eh_frame_added_): Delete.
(Stub_table::tls_get_addr_opt_bctrl_, plt_fde_len_, plt_fde_): New vars.
(Stub_table::init_plt_fde): New functions.
(Stub_table::add_eh_frame, replace_eh_frame): Move definition out
of line. Init and use plt_fde_.
(Stub_table::plt_call_size): Return size for tls_get_addr stub.
Extract alignment code to..
(Stub_table::plt_call_align): ..this new function. Adjust all callers.
(Stub_table::add_plt_call_entry): Set has_tls_get_addr_opt and
tls_get_addr_opt_bctrl, and align after that.
(Stub_table::do_write): Write out tls_get_addr stub.
(Target_powerpc::do_finalize_sections): Emit DT_PPC_OPT
PPC_OPT_TLS/PPC64_OPT_TLS bit.
(Target_powerpc::Relocate::relocate): Don't check for or modify
nop following bl for tls_get_addr stub.
2017-08-29 Alan Modra <amodra@gmail.com>
* symtab.h (Symbol): Split u_ into u1_ and u2_. Adjust accessors

3
gold/options.h
View File

@ -1294,6 +1294,9 @@ class General_options
DEFINE_bool(tls_optimize, options::TWO_DASHES, '\0', true,
N_("(PowerPC/64 only) Optimize GD/LD/IE code to IE/LE"),
N_("(PowerPC/64 only) Don'\''t try to optimize TLS accesses"));
DEFINE_bool(tls_get_addr_optimize, options::TWO_DASHES, '\0', true,
N_("(PowerPC/64 only) Use a special __tls_get_addr call"),
N_("(PowerPC/64 only) Don't use a special __tls_get_addr call"));
DEFINE_bool(toc_optimize, options::TWO_DASHES, '\0', true,
N_("(PowerPC64 only) Optimize TOC code sequences"),

365
gold/powerpc.cc
View File

@ -613,8 +613,10 @@ class Target_powerpc : public Sized_target<size, big_endian>
stub_tables_(), branch_lookup_table_(), branch_info_(), tocsave_loc_(),
plt_thread_safe_(false), plt_localentry0_(false),
plt_localentry0_init_(false), has_localentry0_(false),
has_tls_get_addr_opt_(false),
relax_failed_(false), relax_fail_count_(0),
stub_group_size_(0), savres_section_(0)
stub_group_size_(0), savres_section_(0),
tls_get_addr_(NULL), tls_get_addr_opt_(NULL)
{
}
@ -1081,11 +1083,43 @@ class Target_powerpc : public Sized_target<size, big_endian>
this->set_processor_specific_flags(flags);
}
Symbol*
tls_get_addr_opt() const
{ return this->tls_get_addr_opt_; }
Symbol*
tls_get_addr() const
{ return this->tls_get_addr_; }
// If optimizing __tls_get_addr calls, whether this is the
// "__tls_get_addr" symbol.
bool
is_tls_get_addr_opt(const Symbol* gsym) const
{
return this->tls_get_addr_opt_ && (gsym == this->tls_get_addr_
|| gsym == this->tls_get_addr_opt_);
}
bool
replace_tls_get_addr(const Symbol* gsym) const
{ return this->tls_get_addr_opt_ && gsym == this->tls_get_addr_; }
void
set_has_tls_get_addr_opt()
{ this->has_tls_get_addr_opt_ = true; }
// Offset to toc save stack slot
int
stk_toc() const
{ return this->abiversion() < 2 ? 40 : 24; }
// Offset to linker save stack slot. ELFv2 doesn't have a linker word,
// so use the CR save slot. Used only by __tls_get_addr call stub,
// relying on __tls_get_addr not saving CR itself.
int
stk_linker() const
{ return this->abiversion() < 2 ? 32 : 8; }
private:
class Track_tls
@ -1139,12 +1173,14 @@ class Target_powerpc : public Sized_target<size, big_endian>
{this->tls_get_addr_state_ = SKIP; }
Tls_get_addr
maybe_skip_tls_get_addr_call(unsigned int r_type, const Symbol* gsym)
maybe_skip_tls_get_addr_call(Target_powerpc<size, big_endian>* target,
unsigned int r_type, const Symbol* gsym)
{
bool is_tls_call = ((r_type == elfcpp::R_POWERPC_REL24
|| r_type == elfcpp::R_PPC_PLTREL24)
&& gsym != NULL
&& strcmp(gsym->name(), "__tls_get_addr") == 0);
&& (gsym == target->tls_get_addr()
|| gsym == target->tls_get_addr_opt()));
Tls_get_addr last_tls = this->tls_get_addr_state_;
this->tls_get_addr_state_ = NOT_EXPECTED;
if (is_tls_call && last_tls != EXPECTED)
@ -1549,12 +1585,18 @@ class Target_powerpc : public Sized_target<size, big_endian>
bool plt_localentry0_;
bool plt_localentry0_init_;
bool has_localentry0_;
bool has_tls_get_addr_opt_;
bool relax_failed_;
int relax_fail_count_;
int32_t stub_group_size_;
Output_data_save_res<size, big_endian> *savres_section_;
// The "__tls_get_addr" symbol, if present
Symbol* tls_get_addr_;
// If optimizing __tls_get_addr calls, the "__tls_get_addr_opt" symbol.
Symbol* tls_get_addr_opt_;
};
template<>
@ -2459,6 +2501,36 @@ Target_powerpc<size, big_endian>::do_define_standard_symbols(
false, false);
}
}
this->tls_get_addr_ = symtab->lookup("__tls_get_addr");
if (parameters->options().tls_get_addr_optimize()
&& this->tls_get_addr_ != NULL
&& this->tls_get_addr_->in_reg())
this->tls_get_addr_opt_ = symtab->lookup("__tls_get_addr_opt");
if (this->tls_get_addr_opt_ != NULL)
{
if (this->tls_get_addr_->is_undefined()
|| this->tls_get_addr_->is_from_dynobj())
{
// Make it seem as if references to __tls_get_addr are
// really to __tls_get_addr_opt, so the latter symbol is
// made dynamic, not the former.
this->tls_get_addr_->clear_in_reg();
this->tls_get_addr_opt_->set_in_reg();
}
// We have a non-dynamic definition for __tls_get_addr.
// Make __tls_get_addr_opt the same, if it does not already have
// a non-dynamic definition.
else if (this->tls_get_addr_opt_->is_undefined()
|| this->tls_get_addr_opt_->is_from_dynobj())
{
Sized_symbol<size>* from
= static_cast<Sized_symbol<size>*>(this->tls_get_addr_);
Sized_symbol<size>* to
= static_cast<Sized_symbol<size>*>(this->tls_get_addr_opt_);
symtab->clone<size>(to, from);
}
}
}
// Set up PowerPC target specific relobj.
@ -3030,6 +3102,8 @@ Target_powerpc<size, big_endian>::Branch_info::mark_pltcall(
return false;
Symbol* sym = this->object_->global_symbol(this->r_sym_);
if (target->replace_tls_get_addr(sym))
sym = target->tls_get_addr_opt();
if (sym != NULL && sym->is_forwarder())
sym = symtab->resolve_forwards(sym);
const Sized_symbol<size>* gsym = static_cast<const Sized_symbol<size>*>(sym);
@ -3055,12 +3129,14 @@ Target_powerpc<size, big_endian>::Branch_info::make_stub(
Symbol_table* symtab) const
{
Symbol* sym = this->object_->global_symbol(this->r_sym_);
if (sym != NULL && sym->is_forwarder())
sym = symtab->resolve_forwards(sym);
const Sized_symbol<size>* gsym = static_cast<const Sized_symbol<size>*>(sym);
Target_powerpc<size, big_endian>* target =
static_cast<Target_powerpc<size, big_endian>*>(
parameters->sized_target<size, big_endian>());
if (target->replace_tls_get_addr(sym))
sym = target->tls_get_addr_opt();
if (sym != NULL && sym->is_forwarder())
sym = symtab->resolve_forwards(sym);
const Sized_symbol<size>* gsym = static_cast<const Sized_symbol<size>*>(sym);
bool ok = true;
if (gsym != NULL
@ -3675,6 +3751,8 @@ static const uint32_t add_2_2_11 = 0x7c425a14;
static const uint32_t add_2_2_12 = 0x7c426214;
static const uint32_t add_3_3_2 = 0x7c631214;
static const uint32_t add_3_3_13 = 0x7c636a14;
static const uint32_t add_3_12_2 = 0x7c6c1214;
static const uint32_t add_3_12_13 = 0x7c6c6a14;
static const uint32_t add_11_0_11 = 0x7d605a14;
static const uint32_t add_11_2_11 = 0x7d625a14;
static const uint32_t add_11_11_2 = 0x7d6b1214;
@ -3696,10 +3774,14 @@ static const uint32_t addis_12_12 = 0x3d8c0000;
static const uint32_t b = 0x48000000;
static const uint32_t bcl_20_31 = 0x429f0005;
static const uint32_t bctr = 0x4e800420;
static const uint32_t bctrl = 0x4e800421;
static const uint32_t beqlr = 0x4d820020;
static const uint32_t blr = 0x4e800020;
static const uint32_t bnectr_p4 = 0x4ce20420;
static const uint32_t cmpld_7_12_0 = 0x7fac0040;
static const uint32_t cmpldi_2_0 = 0x28220000;
static const uint32_t cmpdi_11_0 = 0x2c2b0000;
static const uint32_t cmpwi_11_0 = 0x2c0b0000;
static const uint32_t cror_15_15_15 = 0x4def7b82;
static const uint32_t cror_31_31_31 = 0x4ffffb82;
static const uint32_t ld_0_1 = 0xe8010000;
@ -3708,9 +3790,12 @@ static const uint32_t ld_2_1 = 0xe8410000;
static const uint32_t ld_2_2 = 0xe8420000;
static const uint32_t ld_2_11 = 0xe84b0000;
static const uint32_t ld_2_12 = 0xe84c0000;
static const uint32_t ld_11_1 = 0xe9610000;
static const uint32_t ld_11_2 = 0xe9620000;
static const uint32_t ld_11_3 = 0xe9630000;
static const uint32_t ld_11_11 = 0xe96b0000;
static const uint32_t ld_12_2 = 0xe9820000;
static const uint32_t ld_12_3 = 0xe9830000;
static const uint32_t ld_12_11 = 0xe98b0000;
static const uint32_t ld_12_12 = 0xe98c0000;
static const uint32_t lfd_0_1 = 0xc8010000;
@ -3722,17 +3807,22 @@ static const uint32_t lis_11 = 0x3d600000;
static const uint32_t lis_12 = 0x3d800000;
static const uint32_t lvx_0_12_0 = 0x7c0c00ce;
static const uint32_t lwz_0_12 = 0x800c0000;
static const uint32_t lwz_11_3 = 0x81630000;
static const uint32_t lwz_11_11 = 0x816b0000;
static const uint32_t lwz_11_30 = 0x817e0000;
static const uint32_t lwz_12_3 = 0x81830000;
static const uint32_t lwz_12_12 = 0x818c0000;
static const uint32_t lwzu_0_12 = 0x840c0000;
static const uint32_t mflr_0 = 0x7c0802a6;
static const uint32_t mflr_11 = 0x7d6802a6;
static const uint32_t mflr_12 = 0x7d8802a6;
static const uint32_t mr_0_3 = 0x7c601b78;
static const uint32_t mr_3_0 = 0x7c030378;
static const uint32_t mtctr_0 = 0x7c0903a6;
static const uint32_t mtctr_11 = 0x7d6903a6;
static const uint32_t mtctr_12 = 0x7d8903a6;
static const uint32_t mtlr_0 = 0x7c0803a6;
static const uint32_t mtlr_11 = 0x7d6803a6;
static const uint32_t mtlr_12 = 0x7d8803a6;
static const uint32_t nop = 0x60000000;
static const uint32_t ori_0_0_0 = 0x60000000;
@ -3740,6 +3830,7 @@ static const uint32_t srdi_0_0_2 = 0x7800f082;
static const uint32_t std_0_1 = 0xf8010000;
static const uint32_t std_0_12 = 0xf80c0000;
static const uint32_t std_2_1 = 0xf8410000;
static const uint32_t std_11_1 = 0xf9610000;
static const uint32_t stfd_0_1 = 0xd8010000;
static const uint32_t stvx_0_12_0 = 0x7c0c01ce;
static const uint32_t sub_11_11_12 = 0x7d6c5850;
@ -4102,7 +4193,8 @@ class Stub_table : public Output_relaxed_input_section
orig_data_size_(owner->current_data_size()),
plt_size_(0), last_plt_size_(0),
branch_size_(0), last_branch_size_(0), min_size_threshold_(0),
eh_frame_added_(false), need_save_res_(false), uniq_(id)
need_save_res_(false), uniq_(id), tls_get_addr_opt_bctrl_(-1u),
plt_fde_len_(0)
{
this->set_output_section(output_section);
@ -4263,48 +4355,17 @@ class Stub_table : public Output_relaxed_input_section
return false;
}
// Add .eh_frame info for this stub section. Unlike other linker
// generated .eh_frame this is added late in the link, because we
// only want the .eh_frame info if this particular stub section is
// non-empty.
// Generate a suitable FDE to describe code in this stub group.
void
add_eh_frame(Layout* layout)
{
if (!parameters->options().ld_generated_unwind_info())
return;
// Since we add stub .eh_frame info late, it must be placed
// after all other linker generated .eh_frame info so that
// merge mapping need not be updated for input sections.
// There is no provision to use a different CIE to that used
// by .glink.
if (!this->targ_->has_glink())
return;
if (this->plt_size_ + this->branch_size_ + this->need_save_res_ == 0)
return;
layout->add_eh_frame_for_plt(this,
Eh_cie<size>::eh_frame_cie,
sizeof (Eh_cie<size>::eh_frame_cie),
default_fde,
sizeof (default_fde));
this->eh_frame_added_ = true;
}
init_plt_fde();
// Add .eh_frame info for this stub section.
void
remove_eh_frame(Layout* layout)
{
if (this->eh_frame_added_)
{
layout->remove_eh_frame_for_plt(this,
Eh_cie<size>::eh_frame_cie,
sizeof (Eh_cie<size>::eh_frame_cie),
default_fde,
sizeof (default_fde));
this->eh_frame_added_ = false;
}
}
add_eh_frame(Layout* layout);
// Remove .eh_frame info for this stub section.
void
remove_eh_frame(Layout* layout);
Target_powerpc<size, big_endian>*
targ() const
@ -4356,7 +4417,12 @@ class Stub_table : public Output_relaxed_input_section
plt_call_size(typename Plt_stub_entries::const_iterator p) const
{
if (size == 32)
return 16;
{
const Symbol* gsym = p->first.sym_;
if (this->targ_->is_tls_get_addr_opt(gsym))
return 12 * 4;
return 4 * 4;
}
bool is_iplt;
Address plt_addr = this->plt_off(p, &is_iplt);
@ -4370,6 +4436,9 @@ class Stub_table : public Output_relaxed_input_section
got_addr += ppcobj->toc_base_offset();
Address off = plt_addr - got_addr;
unsigned int bytes = 4 * 4 + 4 * (ha(off) != 0);
const Symbol* gsym = p->first.sym_;
if (this->targ_->is_tls_get_addr_opt(gsym))
bytes += 13 * 4;
if (this->targ_->abiversion() < 2)
{
bool static_chain = parameters->options().plt_static_chain();
@ -4379,6 +4448,12 @@ class Stub_table : public Output_relaxed_input_section
+ 8 * thread_safe
+ 4 * (ha(off + 8 + 8 * static_chain) != ha(off)));
}
return bytes;
}
unsigned int
plt_call_align(unsigned int bytes) const
{
unsigned int align = 1 << parameters->options().plt_align();
if (align > 1)
bytes = (bytes + align - 1) & -align;
@ -4518,13 +4593,16 @@ class Stub_table : public Output_relaxed_input_section
// a stub table, it is zero for the first few iterations, then
// increases monotonically.
Address min_size_threshold_;
// Whether .eh_frame info has been created for this stub section.
bool eh_frame_added_;
// Set if this stub group needs a copy of out-of-line register
// save/restore functions.
bool need_save_res_;
// Per stub table unique identifier.
uint32_t uniq_;
// The bctrl in the __tls_get_addr_opt stub, if present.
unsigned int tls_get_addr_opt_bctrl_;
// FDE unwind info for this stub group.
unsigned int plt_fde_len_;
unsigned char plt_fde_[20];
};
// Add a plt call stub, if we do not already have one for this
@ -4553,6 +4631,12 @@ Stub_table<size, big_endian>::add_plt_call_entry(
p.first->second.localentry0_ = 1;
this->targ_->set_has_localentry0();
}
if (this->targ_->is_tls_get_addr_opt(gsym))
{
this->targ_->set_has_tls_get_addr_opt();
this->tls_get_addr_opt_bctrl_ = this->plt_size_ - 5 * 4;
}
this->plt_size_ = this->plt_call_align(this->plt_size_);
}
if (size == 64
&& !tocsave
@ -4578,6 +4662,7 @@ Stub_table<size, big_endian>::add_plt_call_entry(
if (p.second)
{
this->plt_size_ = ent.off_ + this->plt_call_size(p.first);
this->plt_size_ = this->plt_call_align(this->plt_size_);
if (size == 64
&& this->targ_->is_elfv2_localentry0(object, locsym_index))
{
@ -4697,6 +4782,94 @@ Stub_table<size, big_endian>::find_long_branch_entry(
return p->second;
}
// Generate a suitable FDE to describe code in this stub group.
// The __tls_get_addr_opt call stub needs to describe where it saves
// LR, to support exceptions that might be thrown from __tls_get_addr.
template<int size, bool big_endian>
void
Stub_table<size, big_endian>::init_plt_fde()
{
unsigned char* p = this->plt_fde_;
// offset pcrel sdata4, size udata4, and augmentation size byte.
memset (p, 0, 9);
p += 9;
if (this->tls_get_addr_opt_bctrl_ != -1u)
{
unsigned int to_bctrl = this->tls_get_addr_opt_bctrl_ / 4;
if (to_bctrl < 64)
*p++ = elfcpp::DW_CFA_advance_loc + to_bctrl;
else if (to_bctrl < 256)
{
*p++ = elfcpp::DW_CFA_advance_loc1;
*p++ = to_bctrl;
}
else if (to_bctrl < 65536)
{
*p++ = elfcpp::DW_CFA_advance_loc2;
elfcpp::Swap<16, big_endian>::writeval(p, to_bctrl);
p += 2;
}
else
{
*p++ = elfcpp::DW_CFA_advance_loc4;
elfcpp::Swap<32, big_endian>::writeval(p, to_bctrl);
p += 4;
}
*p++ = elfcpp::DW_CFA_offset_extended_sf;
*p++ = 65;
*p++ = -(this->targ_->stk_linker() / 8) & 0x7f;
*p++ = elfcpp::DW_CFA_advance_loc + 4;
*p++ = elfcpp::DW_CFA_restore_extended;
*p++ = 65;
}
this->plt_fde_len_ = p - this->plt_fde_;
}
// Add .eh_frame info for this stub section. Unlike other linker
// generated .eh_frame this is added late in the link, because we
// only want the .eh_frame info if this particular stub section is
// non-empty.
template<int size, bool big_endian>
void
Stub_table<size, big_endian>::add_eh_frame(Layout* layout)
{
if (!parameters->options().ld_generated_unwind_info())
return;
// Since we add stub .eh_frame info late, it must be placed
// after all other linker generated .eh_frame info so that
// merge mapping need not be updated for input sections.
// There is no provision to use a different CIE to that used
// by .glink.
if (!this->targ_->has_glink())
return;
if (this->plt_size_ + this->branch_size_ + this->need_save_res_ == 0)
return;
this->init_plt_fde();
layout->add_eh_frame_for_plt(this,
Eh_cie<size>::eh_frame_cie,
sizeof (Eh_cie<size>::eh_frame_cie),
this->plt_fde_, this->plt_fde_len_);
}
template<int size, bool big_endian>
void
Stub_table<size, big_endian>::remove_eh_frame(Layout* layout)
{
if (this->plt_fde_len_ != 0)
{
layout->remove_eh_frame_for_plt(this,
Eh_cie<size>::eh_frame_cie,
sizeof (Eh_cie<size>::eh_frame_cie),
this->plt_fde_, this->plt_fde_len_);
this->plt_fde_len_ = 0;
}
}
// A class to handle .glink.
template<int size, bool big_endian>
@ -4896,13 +5069,15 @@ Stub_table<size, big_endian>::define_stub_syms(Symbol_table* symtab)
sprintf(localname, "%x", cs->first.locsym_);
symname = localname;
}
else if (this->targ_->is_tls_get_addr_opt(cs->first.sym_))
symname = this->targ_->tls_get_addr_opt()->name();
else
symname = cs->first.sym_->name();
char* name = new char[8 + 10 + strlen(obj) + strlen(symname) + strlen(add) + 1];
sprintf(name, "%08x.plt_call.%s%s%s", this->uniq_, obj, symname, add);
Address value
= this->stub_address() - this->address() + cs->second.off_;
unsigned int stub_size = this->plt_call_size(cs);
unsigned int stub_size = this->plt_call_align(this->plt_call_size(cs));
this->targ_->define_local(symtab, name, this, value, stub_size);
}
}
@ -5011,6 +5186,33 @@ Stub_table<size, big_endian>::do_write(Output_file* of)
}
p = oview + cs->second.off_;
const Symbol* gsym = cs->first.sym_;
if (this->targ_->is_tls_get_addr_opt(gsym))
{
write_insn<big_endian>(p, ld_11_3 + 0);
p += 4;
write_insn<big_endian>(p, ld_12_3 + 8);
p += 4;
write_insn<big_endian>(p, mr_0_3);
p += 4;
write_insn<big_endian>(p, cmpdi_11_0);
p += 4;
write_insn<big_endian>(p, add_3_12_13);
p += 4;
write_insn<big_endian>(p, beqlr);
p += 4;
write_insn<big_endian>(p, mr_3_0);
p += 4;
if (!cs->second.localentry0_)
{
write_insn<big_endian>(p, mflr_11);
p += 4;
write_insn<big_endian>(p, (std_11_1
+ this->targ_->stk_linker()));
p += 4;
}
use_fake_dep = thread_safe;
}
if (ha(off) != 0)
{
if (cs->second.r2save_)
@ -5097,7 +5299,20 @@ Stub_table<size, big_endian>::do_write(Output_file* of)
p += 4;
}
}
if (thread_safe && !use_fake_dep)
if (!cs->second.localentry0_
&& this->targ_->is_tls_get_addr_opt(gsym))
{
write_insn<big_endian>(p, bctrl);
p += 4;
write_insn<big_endian>(p, ld_2_1 + this->targ_->stk_toc());
p += 4;
write_insn<big_endian>(p, ld_11_1 + this->targ_->stk_linker());
p += 4;
write_insn<big_endian>(p, mtlr_11);
p += 4;
write_insn<big_endian>(p, blr);
}
else if (thread_safe && !use_fake_dep)
{
write_insn<big_endian>(p, cmpldi_2_0);
p += 4;
@ -5173,6 +5388,26 @@ Stub_table<size, big_endian>::do_write(Output_file* of)
plt_addr += plt_base;
p = oview + cs->second.off_;
const Symbol* gsym = cs->first.sym_;
if (this->targ_->is_tls_get_addr_opt(gsym))
{
write_insn<big_endian>(p, lwz_11_3 + 0);
p += 4;
write_insn<big_endian>(p, lwz_12_3 + 4);
p += 4;
write_insn<big_endian>(p, mr_0_3);
p += 4;
write_insn<big_endian>(p, cmpwi_11_0);
p += 4;
write_insn<big_endian>(p, add_3_12_2);
p += 4;
write_insn<big_endian>(p, beqlr);
p += 4;
write_insn<big_endian>(p, mr_3_0);
p += 4;
write_insn<big_endian>(p, nop);
p += 4;
}
if (parameters->options().output_is_position_independent())
{
Address got_addr;
@ -6225,7 +6460,7 @@ Target_powerpc<size, big_endian>::Scan::local(
const elfcpp::Sym<size, big_endian>& lsym,
bool is_discarded)
{
this->maybe_skip_tls_get_addr_call(r_type, NULL);
this->maybe_skip_tls_get_addr_call(target, r_type, NULL);
if ((size == 64 && r_type == elfcpp::R_PPC64_TLSGD)
|| (size == 32 && r_type == elfcpp::R_PPC_TLSGD))
@ -6772,9 +7007,15 @@ Target_powerpc<size, big_endian>::Scan::global(
unsigned int r_type,
Symbol* gsym)
{
if (this->maybe_skip_tls_get_addr_call(r_type, gsym) == Track_tls::SKIP)
if (this->maybe_skip_tls_get_addr_call(target, r_type, gsym)
== Track_tls::SKIP)
return;
if (target->replace_tls_get_addr(gsym))
// Change a __tls_get_addr reference to __tls_get_addr_opt
// so dynamic relocs are emitted against the latter symbol.
gsym = target->tls_get_addr_opt();
if ((size == 64 && r_type == elfcpp::R_PPC64_TLSGD)
|| (size == 32 && r_type == elfcpp::R_PPC_TLSGD))
{
@ -7904,6 +8145,8 @@ Target_powerpc<size, big_endian>::do_finalize_sections(
odyn->add_section_plus_offset(elfcpp::DT_PPC_GOT,
this->got_, this->got_->g_o_t());
}
if (this->has_tls_get_addr_opt_)
odyn->add_constant(elfcpp::DT_PPC_OPT, elfcpp::PPC_OPT_TLS);
}
else
{
@ -7915,9 +8158,12 @@ Target_powerpc<size, big_endian>::do_finalize_sections(
(this->glink_->pltresolve_size
- 32));
}
if (this->has_localentry0_)
if (this->has_localentry0_ || this->has_tls_get_addr_opt_)
odyn->add_constant(elfcpp::DT_PPC64_OPT,
elfcpp::PPC64_OPT_LOCALENTRY);
((this->has_localentry0_
? elfcpp::PPC64_OPT_LOCALENTRY : 0)
| (this->has_tls_get_addr_opt_
? elfcpp::PPC64_OPT_TLS : 0)));
}
}
@ -8035,9 +8281,12 @@ Target_powerpc<size, big_endian>::Relocate::relocate(
if (view == NULL)
return true;
if (target->replace_tls_get_addr(gsym))
gsym = static_cast<const Sized_symbol<size>*>(target->tls_get_addr_opt());
const elfcpp::Rela<size, big_endian> rela(preloc);
unsigned int r_type = elfcpp::elf_r_type<size>(rela.get_r_info());
switch (this->maybe_skip_tls_get_addr_call(r_type, gsym))
switch (this->maybe_skip_tls_get_addr_call(target, r_type, gsym))
{
case Track_tls::NOT_EXPECTED:
gold_error_at_location(relinfo, relnum, rela.get_r_offset(),
@ -8162,8 +8411,8 @@ Target_powerpc<size, big_endian>::Relocate::relocate(
{
typedef typename elfcpp::Swap<32, big_endian>::Valtype Valtype;
Valtype* wv = reinterpret_cast<Valtype*>(view);
bool can_plt_call = localentry0;
if (!localentry0 && rela.get_r_offset() + 8 <= view_size)
bool can_plt_call = localentry0 || target->is_tls_get_addr_opt(gsym);
if (!can_plt_call && rela.get_r_offset() + 8 <= view_size)
{
Valtype insn = elfcpp::Swap<32, big_endian>::readval(wv);
Valtype insn2 = elfcpp::Swap<32, big_endian>::readval(wv + 1);

62
gold/resolve.cc
View File

@ -917,6 +917,61 @@ Symbol_table::report_resolve_problem(bool is_error, const char* msg,
gold_info("%s: %s: previous definition here", program_name, objname);
}
// Completely override existing symbol. Everything bar name_,
// version_, and is_forced_local_ flag are copied. version_ is
// cleared if from->version_ is clear. Returns true if this symbol
// should be forced local.
bool
Symbol::clone(const Symbol* from)
{
// Don't allow cloning after dynamic linking info is attached to symbols.
// We aren't prepared to merge such.
gold_assert(!this->has_symtab_index() && !from->has_symtab_index());
gold_assert(!this->has_dynsym_index() && !from->has_dynsym_index());
gold_assert(this->got_offset_list()->get_list() == NULL
&& from->got_offset_list()->get_list() == NULL);
gold_assert(!this->has_plt_offset() && !from->has_plt_offset());
if (!from->version_)
this->version_ = from->version_;
this->u1_ = from->u1_;
this->u2_ = from->u2_;
this->type_ = from->type_;
this->binding_ = from->binding_;
this->visibility_ = from->visibility_;
this->nonvis_ = from->nonvis_;
this->source_ = from->source_;
this->is_def_ = from->is_def_;
this->is_forwarder_ = from->is_forwarder_;
this->has_alias_ = from->has_alias_;
this->needs_dynsym_entry_ = from->needs_dynsym_entry_;
this->in_reg_ = from->in_reg_;
this->in_dyn_ = from->in_dyn_;
this->needs_dynsym_value_ = from->needs_dynsym_value_;
this->has_warning_ = from->has_warning_;
this->is_copied_from_dynobj_ = from->is_copied_from_dynobj_;
this->is_ordinary_shndx_ = from->is_ordinary_shndx_;
this->in_real_elf_ = from->in_real_elf_;
this->is_defined_in_discarded_section_
= from->is_defined_in_discarded_section_;
this->undef_binding_set_ = from->undef_binding_set_;
this->undef_binding_weak_ = from->undef_binding_weak_;
this->is_predefined_ = from->is_predefined_;
this->is_protected_ = from->is_protected_;
this->non_zero_localentry_ = from->non_zero_localentry_;
return !this->is_forced_local_ && from->is_forced_local_;
}
template <int size>
bool
Sized_symbol<size>::clone(const Sized_symbol<size>* from)
{
this->value_ = from->value_;
this->symsize_ = from->symsize_;
return Symbol::clone(from);
}
// A special case of should_override which is only called for a strong
// defined symbol from a regular object file. This is used when
// defining special symbols.
@ -1116,4 +1171,11 @@ Symbol_table::override_with_special<64>(Sized_symbol<64>*,
const Sized_symbol<64>*);
#endif
template
bool
Sized_symbol<32>::clone(const Sized_symbol<32>*);
template
bool
Sized_symbol<64>::clone(const Sized_symbol<64>*);
} // End namespace gold.

28
gold/symtab.h
View File

@ -329,6 +329,11 @@ class Symbol
set_in_reg()
{ this->in_reg_ = true; }
// Forget this symbol was seen in a regular object.
void
clear_in_reg()
{ this->in_reg_ = false; }
// Return whether this symbol has been seen in a dynamic object.
bool
in_dyn() const
@ -893,6 +898,13 @@ class Symbol
set_non_zero_localentry()
{ this->non_zero_localentry_ = true; }
// Completely override existing symbol. Everything bar name_,
// version_, and is_forced_local_ flag are copied. version_ is
// cleared if from->version_ is clear. Returns true if this symbol
// should be forced local.
bool
clone(const Symbol* from);
protected:
// Instances of this class should always be created at a specific
// size.
@ -1182,6 +1194,13 @@ class Sized_symbol : public Symbol
void
allocate_common(Output_data*, Value_type value);
// Completely override existing symbol. Everything bar name_,
// version_, and is_forced_local_ flag are copied. version_ is
// cleared if from->version_ is clear. Returns true if this symbol
// should be forced local.
bool
clone(const Sized_symbol<size>* from);
private:
Sized_symbol(const Sized_symbol&);
Sized_symbol& operator=(const Sized_symbol&);
@ -1687,6 +1706,15 @@ class Symbol_table
version_script() const
{ return version_script_; }
// Completely override existing symbol.
template<int size>
void
clone(Sized_symbol<size>* to, const Sized_symbol<size>* from)
{
if (to->clone(from))
this->force_local(to);
}
private:
Symbol_table(const Symbol_table&);
Symbol_table& operator=(const Symbol_table&);