/*
* Copyright (C) 2011 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 Thumb2 ISA. */
#include "arm64_lir.h"
#include "codegen_arm64.h"
#include "dex/quick/mir_to_lir-inl.h"
#include "gc/accounting/card_table.h"
#include "entrypoints/quick/quick_entrypoints.h"
namespace art {
/*
* The sparse table in the literal pool is an array of <key,displacement>
* pairs. For each set, we'll load them as a pair using ldp.
* The test loop will look something like:
*
* adr r_base, <table>
* ldr r_val, [rA64_SP, v_reg_off]
* mov r_idx, #table_size
* loop:
* cbz r_idx, quit
* ldp r_key, r_disp, [r_base], #8
* sub r_idx, #1
* cmp r_val, r_key
* b.ne loop
* adr r_base, #0 ; This is the instruction from which we compute displacements
* add r_base, r_disp
* br r_base
* quit:
*/
void Arm64Mir2Lir::GenLargeSparseSwitch(MIR* mir, uint32_t table_offset, RegLocation rl_src) {
const uint16_t* table = cu_->insns + current_dalvik_offset_ + table_offset;
if (cu_->verbose) {
DumpSparseSwitchTable(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_;
uint32_t 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);
RegStorage r_base = AllocTempWide();
// Allocate key and disp temps.
RegStorage r_key = AllocTemp();
RegStorage r_disp = AllocTemp();
// Materialize a pointer to the switch table
NewLIR3(kA64Adr2xd, r_base.GetReg(), 0, WrapPointer(tab_rec));
// Set up r_idx
RegStorage r_idx = AllocTemp();
LoadConstant(r_idx, size);
// Entry of loop.
LIR* loop_entry = NewLIR0(kPseudoTargetLabel);
LIR* branch_out = NewLIR2(kA64Cbz2rt, r_idx.GetReg(), 0);
// Load next key/disp.
NewLIR4(kA64LdpPost4rrXD, r_key.GetReg(), r_disp.GetReg(), r_base.GetReg(), 2);
OpRegRegImm(kOpSub, r_idx, r_idx, 1);
// Go to next case, if key does not match.
OpRegReg(kOpCmp, r_key, rl_src.reg);
OpCondBranch(kCondNe, loop_entry);
// Key does match: branch to case label.
LIR* switch_label = NewLIR3(kA64Adr2xd, r_base.GetReg(), 0, -1);
tab_rec->anchor = switch_label;
// Add displacement to base branch address and go!
OpRegRegRegExtend(kOpAdd, r_base, r_base, As64BitReg(r_disp), kA64Sxtw, 0U);
NewLIR1(kA64Br1x, r_base.GetReg());
// Loop exit label.
LIR* loop_exit = NewLIR0(kPseudoTargetLabel);
branch_out->target = loop_exit;
}
void Arm64Mir2Lir::GenLargePackedSwitch(MIR* mir, uint32_t 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_;
uint32_t 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);
RegStorage table_base = AllocTempWide();
// Materialize a pointer to the switch table
NewLIR3(kA64Adr2xd, table_base.GetReg(), 0, WrapPointer(tab_rec));
int low_key = s4FromSwitchData(&table[2]);
RegStorage key_reg;
// Remove the bias, if necessary
if (low_key == 0) {
key_reg = rl_src.reg;
} else {
key_reg = AllocTemp();
OpRegRegImm(kOpSub, key_reg, rl_src.reg, low_key);
}
// Bounds check - if < 0 or >= size continue following switch
OpRegImm(kOpCmp, key_reg, size - 1);
LIR* branch_over = OpCondBranch(kCondHi, NULL);
// Load the displacement from the switch table
RegStorage disp_reg = AllocTemp();
LoadBaseIndexed(table_base, As64BitReg(key_reg), disp_reg, 2, k32);
// Get base branch address.
RegStorage branch_reg = AllocTempWide();
LIR* switch_label = NewLIR3(kA64Adr2xd, branch_reg.GetReg(), 0, -1);
tab_rec->anchor = switch_label;
// Add displacement to base branch address and go!
OpRegRegRegExtend(kOpAdd, branch_reg, branch_reg, As64BitReg(disp_reg), kA64Sxtw, 0U);
NewLIR1(kA64Br1x, branch_reg.GetReg());
// 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 Arm64Mir2Lir::GenFillArrayData(uint32_t 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 */
LoadValueDirectFixed(rl_src, rs_x0);
LoadWordDisp(rs_xSELF, QUICK_ENTRYPOINT_OFFSET(8, pHandleFillArrayData).Int32Value(),
rs_xLR);
// Materialize a pointer to the fill data image
NewLIR3(kA64Adr2xd, rx1, 0, WrapPointer(tab_rec));
ClobberCallerSave();
LIR* call_inst = OpReg(kOpBlx, rs_xLR);
MarkSafepointPC(call_inst);
}
/*
* Handle unlocked -> thin locked transition inline or else call out to quick entrypoint. For more
* details see monitor.cc.
*/
void Arm64Mir2Lir::GenMonitorEnter(int opt_flags, RegLocation rl_src) {
// x0/w0 = object
// w1 = thin lock thread id
// x2 = address of lock word
// w3 = lock word / store failure
// TUNING: How much performance we get when we inline this?
// Since we've already flush all register.
FlushAllRegs();
LoadValueDirectFixed(rl_src, rs_x0); // = TargetReg(kArg0, kRef)
LockCallTemps(); // Prepare for explicit register usage
LIR* null_check_branch = nullptr;
if ((opt_flags & MIR_IGNORE_NULL_CHECK) && !(cu_->disable_opt & (1 << kNullCheckElimination))) {
null_check_branch = nullptr; // No null check.
} else {
// If the null-check fails its handled by the slow-path to reduce exception related meta-data.
if (!cu_->compiler_driver->GetCompilerOptions().GetImplicitNullChecks()) {
null_check_branch = OpCmpImmBranch(kCondEq, rs_x0, 0, NULL);
}
}
Load32Disp(rs_xSELF, Thread::ThinLockIdOffset<8>().Int32Value(), rs_w1);
OpRegRegImm(kOpAdd, rs_x2, rs_x0, mirror::Object::MonitorOffset().Int32Value());
NewLIR2(kA64Ldxr2rX, rw3, rx2);
MarkPossibleNullPointerException(opt_flags);
LIR* not_unlocked_branch = OpCmpImmBranch(kCondNe, rs_w3, 0, NULL);
NewLIR3(kA64Stxr3wrX, rw3, rw1, rx2);
LIR* lock_success_branch = OpCmpImmBranch(kCondEq, rs_w3, 0, NULL);
LIR* slow_path_target = NewLIR0(kPseudoTargetLabel);
not_unlocked_branch->target = slow_path_target;
if (null_check_branch != nullptr) {
null_check_branch->target = slow_path_target;
}
// TODO: move to a slow path.
// Go expensive route - artLockObjectFromCode(obj);
LoadWordDisp(rs_xSELF, QUICK_ENTRYPOINT_OFFSET(8, pLockObject).Int32Value(), rs_xLR);
ClobberCallerSave();
LIR* call_inst = OpReg(kOpBlx, rs_xLR);
MarkSafepointPC(call_inst);
LIR* success_target = NewLIR0(kPseudoTargetLabel);
lock_success_branch->target = success_target;
GenMemBarrier(kLoadAny);
}
/*
* Handle thin locked -> unlocked transition inline or else call out to quick entrypoint. For more
* details see monitor.cc. Note the code below doesn't use ldxr/stxr as the code holds the lock
* and can only give away ownership if its suspended.
*/
void Arm64Mir2Lir::GenMonitorExit(int opt_flags, RegLocation rl_src) {
// x0/w0 = object
// w1 = thin lock thread id
// w2 = lock word
// TUNING: How much performance we get when we inline this?
// Since we've already flush all register.
FlushAllRegs();
LoadValueDirectFixed(rl_src, rs_x0); // Get obj
LockCallTemps(); // Prepare for explicit register usage
LIR* null_check_branch = nullptr;
if ((opt_flags & MIR_IGNORE_NULL_CHECK) && !(cu_->disable_opt & (1 << kNullCheckElimination))) {
null_check_branch = nullptr; // No null check.
} else {
// If the null-check fails its handled by the slow-path to reduce exception related meta-data.
if (!cu_->compiler_driver->GetCompilerOptions().GetImplicitNullChecks()) {
null_check_branch = OpCmpImmBranch(kCondEq, rs_x0, 0, NULL);
}
}
Load32Disp(rs_xSELF, Thread::ThinLockIdOffset<8>().Int32Value(), rs_w1);
Load32Disp(rs_x0, mirror::Object::MonitorOffset().Int32Value(), rs_w2);
MarkPossibleNullPointerException(opt_flags);
LIR* slow_unlock_branch = OpCmpBranch(kCondNe, rs_w1, rs_w2, NULL);
GenMemBarrier(kAnyStore);
Store32Disp(rs_x0, mirror::Object::MonitorOffset().Int32Value(), rs_wzr);
LIR* unlock_success_branch = OpUnconditionalBranch(NULL);
LIR* slow_path_target = NewLIR0(kPseudoTargetLabel);
slow_unlock_branch->target = slow_path_target;
if (null_check_branch != nullptr) {
null_check_branch->target = slow_path_target;
}
// TODO: move to a slow path.
// Go expensive route - artUnlockObjectFromCode(obj);
LoadWordDisp(rs_xSELF, QUICK_ENTRYPOINT_OFFSET(8, pUnlockObject).Int32Value(), rs_xLR);
ClobberCallerSave();
LIR* call_inst = OpReg(kOpBlx, rs_xLR);
MarkSafepointPC(call_inst);
LIR* success_target = NewLIR0(kPseudoTargetLabel);
unlock_success_branch->target = success_target;
}
void Arm64Mir2Lir::GenMoveException(RegLocation rl_dest) {
int ex_offset = Thread::ExceptionOffset<8>().Int32Value();
RegLocation rl_result = EvalLoc(rl_dest, kRefReg, true);
LoadRefDisp(rs_xSELF, ex_offset, rl_result.reg, kNotVolatile);
StoreRefDisp(rs_xSELF, ex_offset, rs_xzr, kNotVolatile);
StoreValue(rl_dest, rl_result);
}
/*
* Mark garbage collection card. Skip if the value we're storing is null.
*/
void Arm64Mir2Lir::MarkGCCard(RegStorage val_reg, RegStorage tgt_addr_reg) {
RegStorage reg_card_base = AllocTempWide();
RegStorage reg_card_no = AllocTempWide(); // Needs to be wide as addr is ref=64b
LIR* branch_over = OpCmpImmBranch(kCondEq, val_reg, 0, NULL);
LoadWordDisp(rs_xSELF, Thread::CardTableOffset<8>().Int32Value(), reg_card_base);
OpRegRegImm(kOpLsr, reg_card_no, tgt_addr_reg, gc::accounting::CardTable::kCardShift);
// TODO(Arm64): generate "strb wB, [xB, wC, uxtw]" rather than "strb wB, [xB, xC]"?
StoreBaseIndexed(reg_card_base, reg_card_no, As32BitReg(reg_card_base),
0, kUnsignedByte);
LIR* target = NewLIR0(kPseudoTargetLabel);
branch_over->target = target;
FreeTemp(reg_card_base);
FreeTemp(reg_card_no);
}
void Arm64Mir2Lir::GenEntrySequence(RegLocation* ArgLocs, RegLocation rl_method) {
/*
* On entry, x0 to x7 are live. Let the register allocation
* mechanism know so it doesn't try to use any of them when
* expanding the frame or flushing.
* Reserve x8 & x9 for temporaries.
*/
LockTemp(rs_x0);
LockTemp(rs_x1);
LockTemp(rs_x2);
LockTemp(rs_x3);
LockTemp(rs_x4);
LockTemp(rs_x5);
LockTemp(rs_x6);
LockTemp(rs_x7);
LockTemp(rs_xIP0);
LockTemp(rs_xIP1);
/* TUNING:
* Use AllocTemp() and reuse LR if possible to give us the freedom on adjusting the number
* of temp registers.
*/
/*
* We can safely skip the stack overflow check if we're
* a leaf *and* our frame size < fudge factor.
*/
bool skip_overflow_check = mir_graph_->MethodIsLeaf() && !FrameNeedsStackCheck(frame_size_, kArm64);
NewLIR0(kPseudoMethodEntry);
const size_t kStackOverflowReservedUsableBytes = GetStackOverflowReservedBytes(kArm64);
const bool large_frame = static_cast<size_t>(frame_size_) > kStackOverflowReservedUsableBytes;
bool generate_explicit_stack_overflow_check = large_frame ||
!cu_->compiler_driver->GetCompilerOptions().GetImplicitStackOverflowChecks();
const int spill_count = num_core_spills_ + num_fp_spills_;
const int spill_size = (spill_count * kArm64PointerSize + 15) & ~0xf; // SP 16 byte alignment.
const int frame_size_without_spills = frame_size_ - spill_size;
if (!skip_overflow_check) {
if (generate_explicit_stack_overflow_check) {
// Load stack limit
LoadWordDisp(rs_xSELF, Thread::StackEndOffset<8>().Int32Value(), rs_xIP1);
} else {
// Implicit stack overflow check.
// Generate a load from [sp, #-framesize]. If this is in the stack
// redzone we will get a segmentation fault.
// TODO: If the frame size is small enough, is it possible to make this a pre-indexed load,
// so that we can avoid the following "sub sp" when spilling?
OpRegRegImm(kOpSub, rs_x8, rs_sp, GetStackOverflowReservedBytes(kArm64));
LoadWordDisp(rs_x8, 0, rs_x8);
MarkPossibleStackOverflowException();
}
}
int spilled_already = 0;
if (spill_size > 0) {
spilled_already = SpillRegs(rs_sp, core_spill_mask_, fp_spill_mask_, frame_size_);
DCHECK(spill_size == spilled_already || frame_size_ == spilled_already);
}
if (spilled_already != frame_size_) {
OpRegImm(kOpSub, rs_sp, frame_size_without_spills);
}
if (!skip_overflow_check) {
if (generate_explicit_stack_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);
// Unwinds stack.
m2l_->OpRegImm(kOpAdd, rs_sp, sp_displace_);
m2l_->ClobberCallerSave();
ThreadOffset<8> func_offset = QUICK_ENTRYPOINT_OFFSET(8, pThrowStackOverflow);
m2l_->LockTemp(rs_xIP0);
m2l_->LoadWordDisp(rs_xSELF, func_offset.Int32Value(), rs_xIP0);
m2l_->NewLIR1(kA64Br1x, rs_xIP0.GetReg());
m2l_->FreeTemp(rs_xIP0);
}
private:
const size_t sp_displace_;
};
LIR* branch = OpCmpBranch(kCondUlt, rs_sp, rs_xIP1, nullptr);
AddSlowPath(new(arena_)StackOverflowSlowPath(this, branch, frame_size_));
}
}
FlushIns(ArgLocs, rl_method);
FreeTemp(rs_x0);
FreeTemp(rs_x1);
FreeTemp(rs_x2);
FreeTemp(rs_x3);
FreeTemp(rs_x4);
FreeTemp(rs_x5);
FreeTemp(rs_x6);
FreeTemp(rs_x7);
FreeTemp(rs_xIP0);
FreeTemp(rs_xIP1);
}
void Arm64Mir2Lir::GenExitSequence() {
/*
* In the exit path, r0/r1 are live - make sure they aren't
* allocated by the register utilities as temps.
*/
LockTemp(rs_x0);
LockTemp(rs_x1);
NewLIR0(kPseudoMethodExit);
UnspillRegs(rs_sp, core_spill_mask_, fp_spill_mask_, frame_size_);
// Finally return.
NewLIR0(kA64Ret);
}
void Arm64Mir2Lir::GenSpecialExitSequence() {
NewLIR0(kA64Ret);
}
} // namespace art