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2010-01-07 Doug Kwan <dougkwan@google.com>

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* arm.cc (Insn_template::Type): New enum value THUMB16_SPECIAL_TYPE.
	(Insn_template::thumb16_bcond_insn): New method declaration.
	(Insn_template): Fix spelling.
	(Stub::thumb16_special): New method declaration.
	(Stub::do_write): Define virtual method which was previously pure
	virtual.
	(Stub::do_thumb16_special): New method declaration.
	(Stub::do_fixed_endian_write): New template member.
	(Reloc_stub::do_write): Remove.
	(Reloc_stub::do_fixed_endian_write): Remove.
	(Cortex_a8_stub): New class definition.
	(Stub_factory::make_cortex_a8_stub): New method definition.
	(Stub_factory::Stub_factory): Add missing static storage class
	qualifier for elf32_arm_stub_a8_veneer_blx.
This commit is contained in:
Doug Kwan 2010-01-07 18:38:43 +00:00
parent ed22650ea5
commit bb0d3eb035
2 changed files with 233 additions and 68 deletions
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17
gold/ChangeLog
View File

@ -1,3 +1,20 @@
2010-01-07 Doug Kwan <dougkwan@google.com>
* arm.cc (Insn_template::Type): New enum value THUMB16_SPECIAL_TYPE.
(Insn_template::thumb16_bcond_insn): New method declaration.
(Insn_template): Fix spelling.
(Stub::thumb16_special): New method declaration.
(Stub::do_write): Define virtual method which was previously pure
virtual.
(Stub::do_thumb16_special): New method declaration.
(Stub::do_fixed_endian_write): New template member.
(Reloc_stub::do_write): Remove.
(Reloc_stub::do_fixed_endian_write): Remove.
(Cortex_a8_stub): New class definition.
(Stub_factory::make_cortex_a8_stub): New method definition.
(Stub_factory::Stub_factory): Add missing static storage class
qualifier for elf32_arm_stub_a8_veneer_blx.
2010-01-07 Ian Lance Taylor <iant@google.com>
PR 10980

284
gold/arm.cc
View File

@ -137,22 +137,27 @@ class Insn_template
enum Type
{
THUMB16_TYPE = 1,
// THUMB16_SPECIAL_TYPE is used by sub-classes of Stub for instruction
// templates with class-specific semantics. Currently this is used
// only by the Cortex_a8_stub class for handling condition codes in
// conditional branches.
THUMB16_SPECIAL_TYPE,
THUMB32_TYPE,
ARM_TYPE,
DATA_TYPE
};
// Factory methods to create instrunction templates in different formats.
// Factory methods to create instruction templates in different formats.
static const Insn_template
thumb16_insn(uint32_t data)
{ return Insn_template(data, THUMB16_TYPE, elfcpp::R_ARM_NONE, 0); }
// A bit of a hack. A Thumb conditional branch, in which the proper
// condition is inserted when we build the stub.
// A Thumb conditional branch, in which the proper condition is inserted
// when we build the stub.
static const Insn_template
thumb16_bcond_insn(uint32_t data)
{ return Insn_template(data, THUMB16_TYPE, elfcpp::R_ARM_NONE, 1); }
{ return Insn_template(data, THUMB16_SPECIAL_TYPE, elfcpp::R_ARM_NONE, 1); }
static const Insn_template
thumb32_insn(uint32_t data)
@ -198,11 +203,11 @@ class Insn_template
reloc_addend() const
{ return this->reloc_addend_; }
// Return size of instrunction template in bytes.
// Return size of instruction template in bytes.
size_t
size() const;
// Return byte-alignment of instrunction template.
// Return byte-alignment of instruction template.
unsigned
alignment() const;
@ -410,16 +415,39 @@ class Stub
write(unsigned char* view, section_size_type view_size, bool big_endian)
{ this->do_write(view, view_size, big_endian); }
// Return the instruction for THUMB16_SPECIAL_TYPE instruction template
// for the i-th instruction.
uint16_t
thumb16_special(size_t i)
{ return this->do_thumb16_special(i); }
protected:
// This must be defined in the child class.
virtual Arm_address
do_reloc_target(size_t) = 0;
// This must be defined in the child class.
// This may be overridden in the child class.
virtual void
do_write(unsigned char*, section_size_type, bool) = 0;
do_write(unsigned char* view, section_size_type view_size, bool big_endian)
{
if (big_endian)
this->do_fixed_endian_write<true>(view, view_size);
else
this->do_fixed_endian_write<false>(view, view_size);
}
// This must be overridden if a child class uses the THUMB16_SPECIAL_TYPE
// instruction template.
virtual uint16_t
do_thumb16_special(size_t)
{ gold_unreachable(); }
private:
// A template to implement do_write.
template<bool big_endian>
void inline
do_fixed_endian_write(unsigned char*, section_size_type);
// Its template.
const Stub_template* stub_template_;
// Offset within the section of containing this stub.
@ -594,7 +622,6 @@ class Reloc_stub : public Stub
friend class Stub_factory;
private:
// Return the relocation target address of the i-th relocation in the
// stub.
Arm_address
@ -605,19 +632,117 @@ class Reloc_stub : public Stub
return this->destination_address_;
}
// A template to implement do_write below.
template<bool big_endian>
void inline
do_fixed_endian_write(unsigned char*, section_size_type);
// Write a stub.
void
do_write(unsigned char* view, section_size_type view_size, bool big_endian);
private:
// Address of destination.
Arm_address destination_address_;
};
// Cortex-A8 stub class. We need a Cortex-A8 stub to redirect any 32-bit
// THUMB branch that meets the following conditions:
//
// 1. The branch straddles across a page boundary. i.e. lower 12-bit of
// branch address is 0xffe.
// 2. The branch target address is in the same page as the first word of the
// branch.
// 3. The branch follows a 32-bit instruction which is not a branch.
//
// To do the fix up, we need to store the address of the branch instruction
// and its target at least. We also need to store the original branch
// instruction bits for the condition code in a conditional branch. The
// condition code is used in a special instruction template. We also want
// to identify input sections needing Cortex-A8 workaround quickly. We store
// extra information about object and section index of the code section
// containing a branch being fixed up. The information is used to mark
// the code section when we finalize the Cortex-A8 stubs.
//
class Cortex_a8_stub : public Stub
{
public:
~Cortex_a8_stub()
{ }
// Return the object of the code section containing the branch being fixed
// up.
Relobj*
relobj() const
{ return this->relobj_; }
// Return the section index of the code section containing the branch being
// fixed up.
unsigned int
shndx() const
{ return this->shndx_; }
// Return the source address of stub. This is the address of the original
// branch instruction. LSB is 1 always set to indicate that it is a THUMB
// instruction.
Arm_address
source_address() const
{ return this->source_address_; }
// Return the destination address of the stub. This is the branch taken
// address of the original branch instruction. LSB is 1 if it is a THUMB
// instruction address.
Arm_address
destination_address() const
{ return this->destination_address_; }
// Return the instruction being fixed up.
uint32_t
original_insn() const
{ return this->original_insn_; }
protected:
// Cortex_a8_stubs are created via a stub factory. So these are protected.
Cortex_a8_stub(const Stub_template* stub_template, Relobj* relobj,
unsigned int shndx, Arm_address source_address,
Arm_address destination_address, uint32_t original_insn)
: Stub(stub_template), relobj_(relobj), shndx_(shndx),
source_address_(source_address | 1U),
destination_address_(destination_address),
original_insn_(original_insn)
{ }
friend class Stub_factory;
// Return the relocation target address of the i-th relocation in the
// stub.
Arm_address
do_reloc_target(size_t i)
{
if (this->stub_template()->type() == arm_stub_a8_veneer_b_cond)
{
// The conditional branch veneer has two relocations.
gold_assert(i < 2);
return i == 0 ? this->source_address_ + 4 : this->destination_address_;
}
else
{
// All other Cortex-A8 stubs have only one relocation.
gold_assert(i == 0);
return this->destination_address_;
}
}
// Return an instruction for the THUMB16_SPECIAL_TYPE instruction template.
uint16_t
do_thumb16_special(size_t);
private:
// Object of the code section containing the branch being fixed up.
Relobj* relobj_;
// Section index of the code section containing the branch begin fixed up.
unsigned int shndx_;
// Source address of original branch.
Arm_address source_address_;
// Destination address of the original branch.
Arm_address destination_address_;
// Original branch instruction. This is needed for copying the condition
// code from a condition branch to its stub.
uint32_t original_insn_;
};
// Stub factory class.
class Stub_factory
@ -640,6 +765,18 @@ class Stub_factory
return new Reloc_stub(this->stub_templates_[stub_type]);
}
// Make a Cortex-A8 stub.
Cortex_a8_stub*
make_cortex_a8_stub(Stub_type stub_type, Relobj* relobj, unsigned int shndx,
Arm_address source, Arm_address destination,
uint32_t original_insn) const
{
gold_assert(stub_type >= arm_stub_cortex_a8_first
&& stub_type <= arm_stub_cortex_a8_last);
return new Cortex_a8_stub(this->stub_templates_[stub_type], relobj, shndx,
source, destination, original_insn);
}
private:
// Constructor and destructor are protected since we only return a single
// instance created in Stub_factory::get_instance().
@ -2728,6 +2865,51 @@ Stub_template::Stub_template(
this->size_ = offset;
}
// Stub methods.
// Template to implement do_write for a specific target endianity.
template<bool big_endian>
void inline
Stub::do_fixed_endian_write(unsigned char* view, section_size_type view_size)
{
const Stub_template* stub_template = this->stub_template();
const Insn_template* insns = stub_template->insns();
// FIXME: We do not handle BE8 encoding yet.
unsigned char* pov = view;
for (size_t i = 0; i < stub_template->insn_count(); i++)
{
switch (insns[i].type())
{
case Insn_template::THUMB16_TYPE:
elfcpp::Swap<16, big_endian>::writeval(pov, insns[i].data() & 0xffff);
break;
case Insn_template::THUMB16_SPECIAL_TYPE:
elfcpp::Swap<16, big_endian>::writeval(
pov,
this->thumb16_special(i));
break;
case Insn_template::THUMB32_TYPE:
{
uint32_t hi = (insns[i].data() >> 16) & 0xffff;
uint32_t lo = insns[i].data() & 0xffff;
elfcpp::Swap<16, big_endian>::writeval(pov, hi);
elfcpp::Swap<16, big_endian>::writeval(pov + 2, lo);
}
break;
case Insn_template::ARM_TYPE:
case Insn_template::DATA_TYPE:
elfcpp::Swap<32, big_endian>::writeval(pov, insns[i].data());
break;
default:
gold_unreachable();
}
pov += insns[i].size();
}
gold_assert(static_cast<section_size_type>(pov - view) == view_size);
}
// Reloc_stub::Key methods.
// Dump a Key as a string for debugging.
@ -2934,57 +3116,23 @@ Reloc_stub::stub_type_for_reloc(
return stub_type;
}
// Template to implement do_write for a specific target endianity.
// Cortex_a8_stub methods.
template<bool big_endian>
void inline
Reloc_stub::do_fixed_endian_write(unsigned char* view,
section_size_type view_size)
// Return the instruction for a THUMB16_SPECIAL_TYPE instruction template.
// I is the position of the instruction template in the stub template.
uint16_t
Cortex_a8_stub::do_thumb16_special(size_t i)
{
const Stub_template* stub_template = this->stub_template();
const Insn_template* insns = stub_template->insns();
// FIXME: We do not handle BE8 encoding yet.
unsigned char* pov = view;
for (size_t i = 0; i < stub_template->insn_count(); i++)
{
switch (insns[i].type())
{
case Insn_template::THUMB16_TYPE:
// Non-zero reloc addends are only used in Cortex-A8 stubs.
gold_assert(insns[i].reloc_addend() == 0);
elfcpp::Swap<16, big_endian>::writeval(pov, insns[i].data() & 0xffff);
break;
case Insn_template::THUMB32_TYPE:
{
uint32_t hi = (insns[i].data() >> 16) & 0xffff;
uint32_t lo = insns[i].data() & 0xffff;
elfcpp::Swap<16, big_endian>::writeval(pov, hi);
elfcpp::Swap<16, big_endian>::writeval(pov + 2, lo);
}
break;
case Insn_template::ARM_TYPE:
case Insn_template::DATA_TYPE:
elfcpp::Swap<32, big_endian>::writeval(pov, insns[i].data());
break;
default:
gold_unreachable();
}
pov += insns[i].size();
}
gold_assert(static_cast<section_size_type>(pov - view) == view_size);
}
// Write a reloc stub to VIEW with endianity specified by BIG_ENDIAN.
void
Reloc_stub::do_write(unsigned char* view, section_size_type view_size,
bool big_endian)
{
if (big_endian)
this->do_fixed_endian_write<true>(view, view_size);
else
this->do_fixed_endian_write<false>(view, view_size);
// The only use of this is to copy condition code from a conditional
// branch being worked around to the corresponding conditional branch in
// to the stub.
gold_assert(this->stub_template()->type() == arm_stub_a8_veneer_b_cond
&& i == 0);
uint16_t data = this->stub_template()->insns()[i].data();
gold_assert((data & 0xff00U) == 0xd000U);
data |= ((this->original_insn_ >> 22) & 0xf) << 8;
return data;
}
// Stub_factory methods.
@ -3162,7 +3310,7 @@ Stub_factory::Stub_factory()
// Stub used for Thumb-2 blx.w instructions. We modified the original blx.w
// instruction (which switches to ARM mode) to point to this stub. Jump to
// the real destination using an ARM-mode branch.
const Insn_template elf32_arm_stub_a8_veneer_blx[] =
static const Insn_template elf32_arm_stub_a8_veneer_blx[] =
{
Insn_template::arm_rel_insn(0xea000000, -8) // b dest
};