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// Copyright (c) 2013, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#include "vm/globals.h" // Needed here to get TARGET_ARCH_ARM.
#if defined(TARGET_ARCH_ARM)
#include "vm/instructions.h"
#include "vm/instructions_arm.h"
#include "vm/compiler/assembler/assembler.h"
#include "vm/constants_arm.h"
#include "vm/cpu.h"
#include "vm/object.h"
namespace dart {
CallPattern::CallPattern(uword pc, const Code& code)
: object_pool_(ObjectPool::Handle(code.GetObjectPool())),
end_(pc),
ic_data_load_end_(0),
target_code_pool_index_(-1),
ic_data_(ICData::Handle()) {
ASSERT(code.ContainsInstructionAt(pc));
// Last instruction: blx lr.
ASSERT(*(reinterpret_cast<uword*>(end_) - 1) == 0xe12fff3e);
Register reg;
ic_data_load_end_ = InstructionPattern::DecodeLoadWordFromPool(
end_ - 2 * Instr::kInstrSize, &reg, &target_code_pool_index_);
ASSERT(reg == CODE_REG);
}
NativeCallPattern::NativeCallPattern(uword pc, const Code& code)
: object_pool_(ObjectPool::Handle(code.GetObjectPool())),
end_(pc),
native_function_pool_index_(-1),
target_code_pool_index_(-1) {
ASSERT(code.ContainsInstructionAt(pc));
// Last instruction: blx lr.
ASSERT(*(reinterpret_cast<uword*>(end_) - 1) == 0xe12fff3e);
Register reg;
uword native_function_load_end = InstructionPattern::DecodeLoadWordFromPool(
end_ - 2 * Instr::kInstrSize, &reg, &target_code_pool_index_);
ASSERT(reg == CODE_REG);
InstructionPattern::DecodeLoadWordFromPool(native_function_load_end, &reg,
&native_function_pool_index_);
ASSERT(reg == R9);
}
RawCode* NativeCallPattern::target() const {
return reinterpret_cast<RawCode*>(
object_pool_.ObjectAt(target_code_pool_index_));
}
void NativeCallPattern::set_target(const Code& new_target) const {
object_pool_.SetObjectAt(target_code_pool_index_, new_target);
// No need to flush the instruction cache, since the code is not modified.
}
NativeFunction NativeCallPattern::native_function() const {
return reinterpret_cast<NativeFunction>(
object_pool_.RawValueAt(native_function_pool_index_));
}
void NativeCallPattern::set_native_function(NativeFunction func) const {
object_pool_.SetRawValueAt(native_function_pool_index_,
reinterpret_cast<uword>(func));
}
// Decodes a load sequence ending at 'end' (the last instruction of the load
// sequence is the instruction before the one at end). Returns a pointer to
// the first instruction in the sequence. Returns the register being loaded
// and the loaded object in the output parameters 'reg' and 'obj'
// respectively.
uword InstructionPattern::DecodeLoadObject(uword end,
const ObjectPool& object_pool,
Register* reg,
Object* obj) {
uword start = 0;
Instr* instr = Instr::At(end - Instr::kInstrSize);
if ((instr->InstructionBits() & 0xfff00000) == 0xe5900000) {
// ldr reg, [reg, #+offset]
intptr_t index = 0;
start = DecodeLoadWordFromPool(end, reg, &index);
*obj = object_pool.ObjectAt(index);
} else {
intptr_t value = 0;
start = DecodeLoadWordImmediate(end, reg, &value);
*obj = reinterpret_cast<RawObject*>(value);
}
return start;
}
// Decodes a load sequence ending at 'end' (the last instruction of the load
// sequence is the instruction before the one at end). Returns a pointer to
// the first instruction in the sequence. Returns the register being loaded
// and the loaded immediate value in the output parameters 'reg' and 'value'
// respectively.
uword InstructionPattern::DecodeLoadWordImmediate(uword end,
Register* reg,
intptr_t* value) {
uword start = end - Instr::kInstrSize;
int32_t instr = Instr::At(start)->InstructionBits();
intptr_t imm = 0;
const ARMVersion version = TargetCPUFeatures::arm_version();
if ((version == ARMv5TE) || (version == ARMv6)) {
ASSERT((instr & 0xfff00000) == 0xe3800000); // orr rd, rd, byte0
imm |= (instr & 0x000000ff);
start -= Instr::kInstrSize;
instr = Instr::At(start)->InstructionBits();
ASSERT((instr & 0xfff00000) == 0xe3800c00); // orr rd, rd, (byte1 rot 12)
imm |= (instr & 0x000000ff);
start -= Instr::kInstrSize;
instr = Instr::At(start)->InstructionBits();
ASSERT((instr & 0xfff00f00) == 0xe3800800); // orr rd, rd, (byte2 rot 8)
imm |= (instr & 0x000000ff);
start -= Instr::kInstrSize;
instr = Instr::At(start)->InstructionBits();
ASSERT((instr & 0xffff0f00) == 0xe3a00400); // mov rd, (byte3 rot 4)
imm |= (instr & 0x000000ff);
*reg = static_cast<Register>((instr & 0x0000f000) >> 12);
*value = imm;
} else {
ASSERT(version == ARMv7);
if ((instr & 0xfff00000) == 0xe3400000) { // movt reg, #imm_hi
imm |= (instr & 0xf0000) << 12;
imm |= (instr & 0xfff) << 16;
start -= Instr::kInstrSize;
instr = Instr::At(start)->InstructionBits();
}
ASSERT((instr & 0xfff00000) == 0xe3000000); // movw reg, #imm_lo
imm |= (instr & 0xf0000) >> 4;
imm |= instr & 0xfff;
*reg = static_cast<Register>((instr & 0xf000) >> 12);
*value = imm;
}
return start;
}
static bool IsLoadWithOffset(int32_t instr,
Register base,
intptr_t* offset,
Register* dst) {
if ((instr & 0xffff0000) == (0xe5900000 | (base << 16))) {
// ldr reg, [base, #+offset]
*offset = instr & 0xfff;
*dst = static_cast<Register>((instr & 0xf000) >> 12);
return true;
}
return false;
}
// Decodes a load sequence ending at 'end' (the last instruction of the load
// sequence is the instruction before the one at end). Returns a pointer to
// the first instruction in the sequence. Returns the register being loaded
// and the index in the pool being read from in the output parameters 'reg'
// and 'index' respectively.
uword InstructionPattern::DecodeLoadWordFromPool(uword end,
Register* reg,
intptr_t* index) {
uword start = end - Instr::kInstrSize;
int32_t instr = Instr::At(start)->InstructionBits();
intptr_t offset = 0;
if (IsLoadWithOffset(instr, PP, &offset, reg)) {
// ldr reg, [PP, #+offset]
} else {
ASSERT((instr & 0xfff00000) == 0xe5900000); // ldr reg, [reg, #+offset]
offset = instr & 0xfff;
start -= Instr::kInstrSize;
instr = Instr::At(start)->InstructionBits();
if ((instr & 0xffff0000) == (0xe2850000 | (PP << 16))) {
// add reg, pp, operand
const intptr_t rot = (instr & 0xf00) >> 7;
const intptr_t imm8 = instr & 0xff;
offset += (imm8 >> rot) | (imm8 << (32 - rot));
*reg = static_cast<Register>((instr & 0xf000) >> 12);
} else {
ASSERT((instr & 0xffff0000) == (0xe0800000 | (PP << 16)));
// add reg, pp, reg
end = DecodeLoadWordImmediate(end, reg, &offset);
}
}
*index = ObjectPool::IndexFromOffset(offset);
return start;
}
bool DecodeLoadObjectFromPoolOrThread(uword pc, const Code& code, Object* obj) {
ASSERT(code.ContainsInstructionAt(pc));
int32_t instr = Instr::At(pc)->InstructionBits();
intptr_t offset;
Register dst;
if (IsLoadWithOffset(instr, PP, &offset, &dst)) {
intptr_t index = ObjectPool::IndexFromOffset(offset);
const ObjectPool& pool = ObjectPool::Handle(code.object_pool());
if (!pool.IsNull()) {
if (pool.TypeAt(index) == ObjectPool::kTaggedObject) {
*obj = pool.ObjectAt(index);
return true;
}
}
} else if (IsLoadWithOffset(instr, THR, &offset, &dst)) {
return Thread::ObjectAtOffset(offset, obj);
}
// TODO(rmacnak): Sequence for loads beyond 12 bits.
return false;
}
RawICData* CallPattern::IcData() {
if (ic_data_.IsNull()) {
Register reg;
InstructionPattern::DecodeLoadObject(ic_data_load_end_, object_pool_, &reg,
&ic_data_);
ASSERT(reg == R9);
}
return ic_data_.raw();
}
RawCode* CallPattern::TargetCode() const {
return reinterpret_cast<RawCode*>(
object_pool_.ObjectAt(target_code_pool_index_));
}
void CallPattern::SetTargetCode(const Code& target_code) const {
object_pool_.SetObjectAt(target_code_pool_index_, target_code);
}
SwitchableCallPattern::SwitchableCallPattern(uword pc, const Code& code)
: object_pool_(ObjectPool::Handle(code.GetObjectPool())),
data_pool_index_(-1),
target_pool_index_(-1) {
ASSERT(code.ContainsInstructionAt(pc));
// Last instruction: blx lr.
ASSERT(*(reinterpret_cast<uword*>(pc) - 1) == 0xe12fff3e);
Register reg;
uword data_load_end = InstructionPattern::DecodeLoadWordFromPool(
pc - Instr::kInstrSize, &reg, &data_pool_index_);
ASSERT(reg == R9);
InstructionPattern::DecodeLoadWordFromPool(data_load_end - Instr::kInstrSize,
&reg, &target_pool_index_);
ASSERT(reg == CODE_REG);
}
RawObject* SwitchableCallPattern::data() const {
return object_pool_.ObjectAt(data_pool_index_);
}
RawCode* SwitchableCallPattern::target() const {
return reinterpret_cast<RawCode*>(object_pool_.ObjectAt(target_pool_index_));
}
void SwitchableCallPattern::SetData(const Object& data) const {
ASSERT(!Object::Handle(object_pool_.ObjectAt(data_pool_index_)).IsCode());
object_pool_.SetObjectAt(data_pool_index_, data);
}
void SwitchableCallPattern::SetTarget(const Code& target) const {
ASSERT(Object::Handle(object_pool_.ObjectAt(target_pool_index_)).IsCode());
object_pool_.SetObjectAt(target_pool_index_, target);
}
ReturnPattern::ReturnPattern(uword pc) : pc_(pc) {}
bool ReturnPattern::IsValid() const {
Instr* bx_lr = Instr::At(pc_);
const int32_t B4 = 1 << 4;
const int32_t B21 = 1 << 21;
const int32_t B24 = 1 << 24;
int32_t instruction = (static_cast<int32_t>(AL) << kConditionShift) | B24 |
B21 | (0xfff << 8) | B4 |
(static_cast<int32_t>(LR) << kRmShift);
const ARMVersion version = TargetCPUFeatures::arm_version();
if ((version == ARMv5TE) || (version == ARMv6)) {
return bx_lr->InstructionBits() == instruction;
} else {
ASSERT(version == ARMv7);
return bx_lr->InstructionBits() == instruction;
}
return false;
}
bool PcRelativeCallPattern::IsValid() const {
// bl <offset>
const uint32_t word = *reinterpret_cast<uint32_t*>(pc_);
const uint32_t cond_all = 0xe0;
const uint32_t branch_link = 0x0b;
return (word >> 24) == (cond_all | branch_link);
}
bool PcRelativeJumpPattern::IsValid() const {
// b <offset>
const uint32_t word = *reinterpret_cast<uint32_t*>(pc_);
const uint32_t cond_all = 0xe0;
const uint32_t branch_nolink = 0x0a;
return (word >> 24) == (cond_all | branch_nolink);
}
intptr_t TypeTestingStubCallPattern::GetSubtypeTestCachePoolIndex() {
// Calls to the type testing stubs look like:
// ldr R3, [PP+idx]
// blx R9
// Ensure the caller of the type testing stub (whose return address is [pc_])
// branched via the `blx R9` instruction.
ASSERT(*reinterpret_cast<uint32_t*>(pc_ - Instr::kInstrSize) == 0xe12fff39);
const uword load_instr_end = pc_ - Instr::kInstrSize;
Register reg;
intptr_t pool_index = -1;
InstructionPattern::DecodeLoadWordFromPool(load_instr_end, &reg, &pool_index);
ASSERT(reg == R3);
return pool_index;
}
} // namespace dart
#endif // defined TARGET_ARCH_ARM