/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* This file contains codegen for the X86 ISA */
#include "codegen_x86.h"
#include "dex/quick/mir_to_lir-inl.h"
#include "gc/accounting/card_table.h"
#include "x86_lir.h"
namespace art {
/*
* The sparse table in the literal pool is an array of <key,displacement>
* pairs.
*/
void X86Mir2Lir::GenLargeSparseSwitch(MIR* mir, DexOffset table_offset, RegLocation rl_src) {
const uint16_t* table = cu_->insns + current_dalvik_offset_ + table_offset;
if (cu_->verbose) {
DumpSparseSwitchTable(table);
}
int entries = table[1];
const int32_t* keys = reinterpret_cast<const int32_t*>(&table[2]);
const int32_t* targets = &keys[entries];
rl_src = LoadValue(rl_src, kCoreReg);
for (int i = 0; i < entries; i++) {
int key = keys[i];
BasicBlock* case_block =
mir_graph_->FindBlock(current_dalvik_offset_ + targets[i]);
OpCmpImmBranch(kCondEq, rl_src.reg, key, &block_label_list_[case_block->id]);
}
}
/*
* Code pattern will look something like:
*
* mov r_val, ..
* call 0
* pop r_start_of_method
* sub r_start_of_method, ..
* mov r_key_reg, r_val
* sub r_key_reg, low_key
* cmp r_key_reg, size-1 ; bound check
* ja done
* mov r_disp, [r_start_of_method + r_key_reg * 4 + table_offset]
* add r_start_of_method, r_disp
* jmp r_start_of_method
* done:
*/
void X86Mir2Lir::GenLargePackedSwitch(MIR* mir, DexOffset table_offset, RegLocation rl_src) {
const uint16_t* table = cu_->insns + current_dalvik_offset_ + table_offset;
if (cu_->verbose) {
DumpPackedSwitchTable(table);
}
// Add the table to the list - we'll process it later
SwitchTable* tab_rec =
static_cast<SwitchTable*>(arena_->Alloc(sizeof(SwitchTable), kArenaAllocData));
tab_rec->table = table;
tab_rec->vaddr = current_dalvik_offset_;
int size = table[1];
tab_rec->targets = static_cast<LIR**>(arena_->Alloc(size * sizeof(LIR*),
kArenaAllocLIR));
switch_tables_.Insert(tab_rec);
// Get the switch value
rl_src = LoadValue(rl_src, kCoreReg);
// NewLIR0(kX86Bkpt);
// Materialize a pointer to the switch table
RegStorage start_of_method_reg;
if (base_of_code_ != nullptr) {
// We can use the saved value.
RegLocation rl_method = mir_graph_->GetRegLocation(base_of_code_->s_reg_low);
if (rl_method.wide) {
rl_method = LoadValueWide(rl_method, kCoreReg);
} else {
rl_method = LoadValue(rl_method, kCoreReg);
}
start_of_method_reg = rl_method.reg;
store_method_addr_used_ = true;
} else {
start_of_method_reg = AllocTempRef();
NewLIR1(kX86StartOfMethod, start_of_method_reg.GetReg());
}
DCHECK_EQ(start_of_method_reg.Is64Bit(), cu_->target64);
int low_key = s4FromSwitchData(&table[2]);
RegStorage keyReg;
// Remove the bias, if necessary
if (low_key == 0) {
keyReg = rl_src.reg;
} else {
keyReg = AllocTemp();
OpRegRegImm(kOpSub, keyReg, rl_src.reg, low_key);
}
// Bounds check - if < 0 or >= size continue following switch
OpRegImm(kOpCmp, keyReg, size - 1);
LIR* branch_over = OpCondBranch(kCondHi, NULL);
// Load the displacement from the switch table
RegStorage disp_reg = AllocTemp();
NewLIR5(kX86PcRelLoadRA, disp_reg.GetReg(), start_of_method_reg.GetReg(), keyReg.GetReg(),
2, WrapPointer(tab_rec));
// Add displacement to start of method
OpRegReg(kOpAdd, start_of_method_reg, cu_->target64 ? As64BitReg(disp_reg) : disp_reg);
// ..and go!
LIR* switch_branch = NewLIR1(kX86JmpR, start_of_method_reg.GetReg());
tab_rec->anchor = switch_branch;
/* branch_over target here */
LIR* target = NewLIR0(kPseudoTargetLabel);
branch_over->target = target;
}
/*
* Array data table format:
* ushort ident = 0x0300 magic value
* ushort width width of each element in the table
* uint size number of elements in the table
* ubyte data[size*width] table of data values (may contain a single-byte
* padding at the end)
*
* Total size is 4+(width * size + 1)/2 16-bit code units.
*/
void X86Mir2Lir::GenFillArrayData(DexOffset table_offset, RegLocation rl_src) {
const uint16_t* table = cu_->insns + current_dalvik_offset_ + table_offset;
// Add the table to the list - we'll process it later
FillArrayData* tab_rec =
static_cast<FillArrayData*>(arena_->Alloc(sizeof(FillArrayData), kArenaAllocData));
tab_rec->table = table;
tab_rec->vaddr = current_dalvik_offset_;
uint16_t width = tab_rec->table[1];
uint32_t size = tab_rec->table[2] | ((static_cast<uint32_t>(tab_rec->table[3])) << 16);
tab_rec->size = (size * width) + 8;
fill_array_data_.Insert(tab_rec);
// Making a call - use explicit registers
FlushAllRegs(); /* Everything to home location */
RegStorage array_ptr = TargetReg(kArg0, kRef);
RegStorage payload = TargetPtrReg(kArg1);
RegStorage method_start = TargetPtrReg(kArg2);
LoadValueDirectFixed(rl_src, array_ptr);
// Materialize a pointer to the fill data image
if (base_of_code_ != nullptr) {
// We can use the saved value.
RegLocation rl_method = mir_graph_->GetRegLocation(base_of_code_->s_reg_low);
if (rl_method.wide) {
LoadValueDirectWide(rl_method, method_start);
} else {
LoadValueDirect(rl_method, method_start);
}
store_method_addr_used_ = true;
} else {
NewLIR1(kX86StartOfMethod, method_start.GetReg());
}
NewLIR2(kX86PcRelAdr, payload.GetReg(), WrapPointer(tab_rec));
OpRegReg(kOpAdd, payload, method_start);
CallRuntimeHelperRegReg(kQuickHandleFillArrayData, array_ptr, payload, true);
}
void X86Mir2Lir::GenMoveException(RegLocation rl_dest) {
int ex_offset = cu_->target64 ?
Thread::ExceptionOffset<8>().Int32Value() :
Thread::ExceptionOffset<4>().Int32Value();
RegLocation rl_result = EvalLoc(rl_dest, kRefReg, true);
NewLIR2(cu_->target64 ? kX86Mov64RT : kX86Mov32RT, rl_result.reg.GetReg(), ex_offset);
NewLIR2(cu_->target64 ? kX86Mov64TI : kX86Mov32TI, ex_offset, 0);
StoreValue(rl_dest, rl_result);
}
/*
* Mark garbage collection card. Skip if the value we're storing is null.
*/
void X86Mir2Lir::MarkGCCard(RegStorage val_reg, RegStorage tgt_addr_reg) {
DCHECK_EQ(tgt_addr_reg.Is64Bit(), cu_->target64);
DCHECK_EQ(val_reg.Is64Bit(), cu_->target64);
RegStorage reg_card_base = AllocTempRef();
RegStorage reg_card_no = AllocTempRef();
LIR* branch_over = OpCmpImmBranch(kCondEq, val_reg, 0, NULL);
int ct_offset = cu_->target64 ?
Thread::CardTableOffset<8>().Int32Value() :
Thread::CardTableOffset<4>().Int32Value();
NewLIR2(cu_->target64 ? kX86Mov64RT : kX86Mov32RT, reg_card_base.GetReg(), ct_offset);
OpRegRegImm(kOpLsr, reg_card_no, tgt_addr_reg, gc::accounting::CardTable::kCardShift);
StoreBaseIndexed(reg_card_base, reg_card_no, reg_card_base, 0, kUnsignedByte);
LIR* target = NewLIR0(kPseudoTargetLabel);
branch_over->target = target;
FreeTemp(reg_card_base);
FreeTemp(reg_card_no);
}
void X86Mir2Lir::GenEntrySequence(RegLocation* ArgLocs, RegLocation rl_method) {
/*
* On entry, rX86_ARG0, rX86_ARG1, rX86_ARG2 are live. Let the register
* allocation mechanism know so it doesn't try to use any of them when
* expanding the frame or flushing. This leaves the utility
* code with no spare temps.
*/
LockTemp(rs_rX86_ARG0);
LockTemp(rs_rX86_ARG1);
LockTemp(rs_rX86_ARG2);
/*
* We can safely skip the stack overflow check if we're
* a leaf *and* our frame size < fudge factor.
*/
InstructionSet isa = cu_->target64 ? kX86_64 : kX86;
bool skip_overflow_check = mir_graph_->MethodIsLeaf() && !FrameNeedsStackCheck(frame_size_, isa);
// If we doing an implicit stack overflow check, perform the load immediately
// before the stack pointer is decremented and anything is saved.
if (!skip_overflow_check &&
cu_->compiler_driver->GetCompilerOptions().GetImplicitStackOverflowChecks()) {
// Implicit stack overflow check.
// test eax,[esp + -overflow]
int overflow = GetStackOverflowReservedBytes(isa);
NewLIR3(kX86Test32RM, rs_rAX.GetReg(), rs_rX86_SP.GetReg(), -overflow);
MarkPossibleStackOverflowException();
}
/* Build frame, return address already on stack */
stack_decrement_ = OpRegImm(kOpSub, rs_rX86_SP, frame_size_ -
GetInstructionSetPointerSize(cu_->instruction_set));
NewLIR0(kPseudoMethodEntry);
/* Spill core callee saves */
SpillCoreRegs();
SpillFPRegs();
if (!skip_overflow_check) {
class StackOverflowSlowPath : public LIRSlowPath {
public:
StackOverflowSlowPath(Mir2Lir* m2l, LIR* branch, size_t sp_displace)
: LIRSlowPath(m2l, m2l->GetCurrentDexPc(), branch, nullptr), sp_displace_(sp_displace) {
}
void Compile() OVERRIDE {
m2l_->ResetRegPool();
m2l_->ResetDefTracking();
GenerateTargetLabel(kPseudoThrowTarget);
m2l_->OpRegImm(kOpAdd, rs_rX86_SP, sp_displace_);
m2l_->ClobberCallerSave();
// Assumes codegen and target are in thumb2 mode.
m2l_->CallHelper(RegStorage::InvalidReg(), kQuickThrowStackOverflow,
false /* MarkSafepointPC */, false /* UseLink */);
}
private:
const size_t sp_displace_;
};
if (!cu_->compiler_driver->GetCompilerOptions().GetImplicitStackOverflowChecks()) {
// TODO: for large frames we should do something like:
// spill ebp
// lea ebp, [esp + frame_size]
// cmp ebp, fs:[stack_end_]
// jcc stack_overflow_exception
// mov esp, ebp
// in case a signal comes in that's not using an alternate signal stack and the large frame
// may have moved us outside of the reserved area at the end of the stack.
// cmp rs_rX86_SP, fs:[stack_end_]; jcc throw_slowpath
if (cu_->target64) {
OpRegThreadMem(kOpCmp, rs_rX86_SP, Thread::StackEndOffset<8>());
} else {
OpRegThreadMem(kOpCmp, rs_rX86_SP, Thread::StackEndOffset<4>());
}
LIR* branch = OpCondBranch(kCondUlt, nullptr);
AddSlowPath(
new(arena_)StackOverflowSlowPath(this, branch,
frame_size_ -
GetInstructionSetPointerSize(cu_->instruction_set)));
}
}
FlushIns(ArgLocs, rl_method);
if (base_of_code_ != nullptr) {
RegStorage method_start = TargetPtrReg(kArg0);
// We have been asked to save the address of the method start for later use.
setup_method_address_[0] = NewLIR1(kX86StartOfMethod, method_start.GetReg());
int displacement = SRegOffset(base_of_code_->s_reg_low);
// Native pointer - must be natural word size.
setup_method_address_[1] = StoreBaseDisp(rs_rX86_SP, displacement, method_start,
cu_->target64 ? k64 : k32, kNotVolatile);
}
FreeTemp(rs_rX86_ARG0);
FreeTemp(rs_rX86_ARG1);
FreeTemp(rs_rX86_ARG2);
}
void X86Mir2Lir::GenExitSequence() {
/*
* In the exit path, rX86_RET0/rX86_RET1 are live - make sure they aren't
* allocated by the register utilities as temps.
*/
LockTemp(rs_rX86_RET0);
LockTemp(rs_rX86_RET1);
NewLIR0(kPseudoMethodExit);
UnSpillCoreRegs();
UnSpillFPRegs();
/* Remove frame except for return address */
stack_increment_ = OpRegImm(kOpAdd, rs_rX86_SP, frame_size_ - GetInstructionSetPointerSize(cu_->instruction_set));
NewLIR0(kX86Ret);
}
void X86Mir2Lir::GenSpecialExitSequence() {
NewLIR0(kX86Ret);
}
void X86Mir2Lir::GenImplicitNullCheck(RegStorage reg, int opt_flags) {
if (!(cu_->disable_opt & (1 << kNullCheckElimination)) && (opt_flags & MIR_IGNORE_NULL_CHECK)) {
return;
}
// Implicit null pointer check.
// test eax,[arg1+0]
NewLIR3(kX86Test32RM, rs_rAX.GetReg(), reg.GetReg(), 0);
MarkPossibleNullPointerException(opt_flags);
}
} // namespace art