/* * 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 "arm_lir.h" #include "codegen_arm.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 * pairs. For each set, we'll load them as a pair using ldmia. * This means that the register number of the temp we use for the key * must be lower than the reg for the displacement. * * The test loop will look something like: * * adr r_base, * ldr r_val, [rARM_SP, v_reg_off] * mov r_idx, #table_size * lp: * ldmia r_base!, {r_key, r_disp} * sub r_idx, #1 * cmp r_val, r_key * ifeq * add rARM_PC, r_disp ; This is the branch from which we compute displacement * cbnz r_idx, lp */ void ArmMir2Lir::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(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(arena_->Alloc(size * sizeof(LIR*), kArenaAllocLIR)); switch_tables_.Insert(tab_rec); // Get the switch value rl_src = LoadValue(rl_src, kCoreReg); RegStorage r_base = AllocTemp(); /* Allocate key and disp temps */ RegStorage r_key = AllocTemp(); RegStorage r_disp = AllocTemp(); // Make sure r_key's register number is less than r_disp's number for ldmia if (r_key.GetReg() > r_disp.GetReg()) { RegStorage tmp = r_disp; r_disp = r_key; r_key = tmp; } // Materialize a pointer to the switch table NewLIR3(kThumb2Adr, r_base.GetReg(), 0, WrapPointer(tab_rec)); // Set up r_idx RegStorage r_idx = AllocTemp(); LoadConstant(r_idx, size); // Establish loop branch target LIR* target = NewLIR0(kPseudoTargetLabel); // Load next key/disp NewLIR2(kThumb2LdmiaWB, r_base.GetReg(), (1 << r_key.GetRegNum()) | (1 << r_disp.GetRegNum())); OpRegReg(kOpCmp, r_key, rl_src.reg); // Go if match. NOTE: No instruction set switch here - must stay Thumb2 LIR* it = OpIT(kCondEq, ""); LIR* switch_branch = NewLIR1(kThumb2AddPCR, r_disp.GetReg()); OpEndIT(it); tab_rec->anchor = switch_branch; // Needs to use setflags encoding here OpRegRegImm(kOpSub, r_idx, r_idx, 1); // For value == 1, this should set flags. DCHECK(last_lir_insn_->u.m.def_mask->HasBit(ResourceMask::kCCode)); OpCondBranch(kCondNe, target); } void ArmMir2Lir::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(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(arena_->Alloc(size * sizeof(LIR*), kArenaAllocLIR)); switch_tables_.Insert(tab_rec); // Get the switch value rl_src = LoadValue(rl_src, kCoreReg); RegStorage table_base = AllocTemp(); // Materialize a pointer to the switch table NewLIR3(kThumb2Adr, table_base.GetReg(), 0, WrapPointer(tab_rec)); 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(); LoadBaseIndexed(table_base, keyReg, disp_reg, 2, k32); // ..and go! NOTE: No instruction set switch here - must stay Thumb2 LIR* switch_branch = NewLIR1(kThumb2AddPCR, disp_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 ArmMir2Lir::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(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(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_r0); LoadWordDisp(rs_rARM_SELF, QUICK_ENTRYPOINT_OFFSET(4, pHandleFillArrayData).Int32Value(), rs_rARM_LR); // Materialize a pointer to the fill data image NewLIR3(kThumb2Adr, rs_r1.GetReg(), 0, WrapPointer(tab_rec)); ClobberCallerSave(); LIR* call_inst = OpReg(kOpBlx, rs_rARM_LR); MarkSafepointPC(call_inst); } /* * Handle unlocked -> thin locked transition inline or else call out to quick entrypoint. For more * details see monitor.cc. */ void ArmMir2Lir::GenMonitorEnter(int opt_flags, RegLocation rl_src) { FlushAllRegs(); // FIXME: need separate LoadValues for object references. LoadValueDirectFixed(rl_src, rs_r0); // Get obj LockCallTemps(); // Prepare for explicit register usage constexpr bool kArchVariantHasGoodBranchPredictor = false; // TODO: true if cortex-A15. if (kArchVariantHasGoodBranchPredictor) { 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_r0, 0, NULL); } } Load32Disp(rs_rARM_SELF, Thread::ThinLockIdOffset<4>().Int32Value(), rs_r2); NewLIR3(kThumb2Ldrex, rs_r1.GetReg(), rs_r0.GetReg(), mirror::Object::MonitorOffset().Int32Value() >> 2); MarkPossibleNullPointerException(opt_flags); LIR* not_unlocked_branch = OpCmpImmBranch(kCondNe, rs_r1, 0, NULL); NewLIR4(kThumb2Strex, rs_r1.GetReg(), rs_r2.GetReg(), rs_r0.GetReg(), mirror::Object::MonitorOffset().Int32Value() >> 2); LIR* lock_success_branch = OpCmpImmBranch(kCondEq, rs_r1, 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_rARM_SELF, QUICK_ENTRYPOINT_OFFSET(4, pLockObject).Int32Value(), rs_rARM_LR); ClobberCallerSave(); LIR* call_inst = OpReg(kOpBlx, rs_rARM_LR); MarkSafepointPC(call_inst); LIR* success_target = NewLIR0(kPseudoTargetLabel); lock_success_branch->target = success_target; GenMemBarrier(kLoadAny); } else { // Explicit null-check as slow-path is entered using an IT. GenNullCheck(rs_r0, opt_flags); Load32Disp(rs_rARM_SELF, Thread::ThinLockIdOffset<4>().Int32Value(), rs_r2); NewLIR3(kThumb2Ldrex, rs_r1.GetReg(), rs_r0.GetReg(), mirror::Object::MonitorOffset().Int32Value() >> 2); MarkPossibleNullPointerException(opt_flags); OpRegImm(kOpCmp, rs_r1, 0); LIR* it = OpIT(kCondEq, ""); NewLIR4(kThumb2Strex/*eq*/, rs_r1.GetReg(), rs_r2.GetReg(), rs_r0.GetReg(), mirror::Object::MonitorOffset().Int32Value() >> 2); OpEndIT(it); OpRegImm(kOpCmp, rs_r1, 0); it = OpIT(kCondNe, "T"); // Go expensive route - artLockObjectFromCode(self, obj); LoadWordDisp/*ne*/(rs_rARM_SELF, QUICK_ENTRYPOINT_OFFSET(4, pLockObject).Int32Value(), rs_rARM_LR); ClobberCallerSave(); LIR* call_inst = OpReg(kOpBlx/*ne*/, rs_rARM_LR); OpEndIT(it); MarkSafepointPC(call_inst); 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 ldrex/strex as the code holds the lock * and can only give away ownership if its suspended. */ void ArmMir2Lir::GenMonitorExit(int opt_flags, RegLocation rl_src) { FlushAllRegs(); LoadValueDirectFixed(rl_src, rs_r0); // Get obj LockCallTemps(); // Prepare for explicit register usage LIR* null_check_branch = nullptr; Load32Disp(rs_rARM_SELF, Thread::ThinLockIdOffset<4>().Int32Value(), rs_r2); constexpr bool kArchVariantHasGoodBranchPredictor = false; // TODO: true if cortex-A15. if (kArchVariantHasGoodBranchPredictor) { 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_r0, 0, NULL); } } Load32Disp(rs_r0, mirror::Object::MonitorOffset().Int32Value(), rs_r1); MarkPossibleNullPointerException(opt_flags); LoadConstantNoClobber(rs_r3, 0); LIR* slow_unlock_branch = OpCmpBranch(kCondNe, rs_r1, rs_r2, NULL); GenMemBarrier(kAnyStore); Store32Disp(rs_r0, mirror::Object::MonitorOffset().Int32Value(), rs_r3); 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_rARM_SELF, QUICK_ENTRYPOINT_OFFSET(4, pUnlockObject).Int32Value(), rs_rARM_LR); ClobberCallerSave(); LIR* call_inst = OpReg(kOpBlx, rs_rARM_LR); MarkSafepointPC(call_inst); LIR* success_target = NewLIR0(kPseudoTargetLabel); unlock_success_branch->target = success_target; } else { // Explicit null-check as slow-path is entered using an IT. GenNullCheck(rs_r0, opt_flags); Load32Disp(rs_r0, mirror::Object::MonitorOffset().Int32Value(), rs_r1); // Get lock MarkPossibleNullPointerException(opt_flags); Load32Disp(rs_rARM_SELF, Thread::ThinLockIdOffset<4>().Int32Value(), rs_r2); LoadConstantNoClobber(rs_r3, 0); // Is lock unheld on lock or held by us (==thread_id) on unlock? OpRegReg(kOpCmp, rs_r1, rs_r2); LIR* it = OpIT(kCondEq, "EE"); if (GenMemBarrier(kAnyStore)) { UpdateIT(it, "TEE"); } Store32Disp/*eq*/(rs_r0, mirror::Object::MonitorOffset().Int32Value(), rs_r3); // Go expensive route - UnlockObjectFromCode(obj); LoadWordDisp/*ne*/(rs_rARM_SELF, QUICK_ENTRYPOINT_OFFSET(4, pUnlockObject).Int32Value(), rs_rARM_LR); ClobberCallerSave(); LIR* call_inst = OpReg(kOpBlx/*ne*/, rs_rARM_LR); OpEndIT(it); MarkSafepointPC(call_inst); } } void ArmMir2Lir::GenMoveException(RegLocation rl_dest) { int ex_offset = Thread::ExceptionOffset<4>().Int32Value(); RegLocation rl_result = EvalLoc(rl_dest, kRefReg, true); RegStorage reset_reg = AllocTempRef(); LoadRefDisp(rs_rARM_SELF, ex_offset, rl_result.reg, kNotVolatile); LoadConstant(reset_reg, 0); StoreRefDisp(rs_rARM_SELF, ex_offset, reset_reg, kNotVolatile); FreeTemp(reset_reg); StoreValue(rl_dest, rl_result); } /* * Mark garbage collection card. Skip if the value we're storing is null. */ void ArmMir2Lir::MarkGCCard(RegStorage val_reg, RegStorage tgt_addr_reg) { RegStorage reg_card_base = AllocTemp(); RegStorage reg_card_no = AllocTemp(); LIR* branch_over = OpCmpImmBranch(kCondEq, val_reg, 0, NULL); LoadWordDisp(rs_rARM_SELF, Thread::CardTableOffset<4>().Int32Value(), reg_card_base); 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 ArmMir2Lir::GenEntrySequence(RegLocation* ArgLocs, RegLocation rl_method) { int spill_count = num_core_spills_ + num_fp_spills_; /* * On entry, r0, r1, r2 & r3 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 a single temp: r12. This should be enough. */ LockTemp(rs_r0); LockTemp(rs_r1); LockTemp(rs_r2); LockTemp(rs_r3); /* * 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_, kArm); NewLIR0(kPseudoMethodEntry); const size_t kStackOverflowReservedUsableBytes = GetStackOverflowReservedBytes(kArm); bool large_frame = (static_cast(frame_size_) > kStackOverflowReservedUsableBytes); bool generate_explicit_stack_overflow_check = large_frame || !cu_->compiler_driver->GetCompilerOptions().GetImplicitStackOverflowChecks(); if (!skip_overflow_check) { if (generate_explicit_stack_overflow_check) { if (!large_frame) { /* Load stack limit */ LockTemp(rs_r12); Load32Disp(rs_rARM_SELF, Thread::StackEndOffset<4>().Int32Value(), rs_r12); } } else { // Implicit stack overflow check. // Generate a load from [sp, #-overflowsize]. If this is in the stack // redzone we will get a segmentation fault. // // Caveat coder: if someone changes the kStackOverflowReservedBytes value // we need to make sure that it's loadable in an immediate field of // a sub instruction. Otherwise we will get a temp allocation and the // code size will increase. // // This is done before the callee save instructions to avoid any possibility // of these overflowing. This uses r12 and that's never saved in a callee // save. OpRegRegImm(kOpSub, rs_r12, rs_rARM_SP, GetStackOverflowReservedBytes(kArm)); Load32Disp(rs_r12, 0, rs_r12); MarkPossibleStackOverflowException(); } } /* Spill core callee saves */ NewLIR1(kThumb2Push, core_spill_mask_); /* Need to spill any FP regs? */ if (num_fp_spills_) { /* * NOTE: fp spills are a little different from core spills in that * they are pushed as a contiguous block. When promoting from * the fp set, we must allocate all singles from s16..highest-promoted */ NewLIR1(kThumb2VPushCS, num_fp_spills_); } const int spill_size = spill_count * 4; const int frame_size_without_spills = frame_size_ - spill_size; if (!skip_overflow_check) { if (generate_explicit_stack_overflow_check) { class StackOverflowSlowPath : public LIRSlowPath { public: StackOverflowSlowPath(Mir2Lir* m2l, LIR* branch, bool restore_lr, size_t sp_displace) : LIRSlowPath(m2l, m2l->GetCurrentDexPc(), branch, nullptr), restore_lr_(restore_lr), sp_displace_(sp_displace) { } void Compile() OVERRIDE { m2l_->ResetRegPool(); m2l_->ResetDefTracking(); GenerateTargetLabel(kPseudoThrowTarget); if (restore_lr_) { m2l_->LoadWordDisp(rs_rARM_SP, sp_displace_ - 4, rs_rARM_LR); } m2l_->OpRegImm(kOpAdd, rs_rARM_SP, sp_displace_); m2l_->ClobberCallerSave(); ThreadOffset<4> func_offset = QUICK_ENTRYPOINT_OFFSET(4, pThrowStackOverflow); // Load the entrypoint directly into the pc instead of doing a load + branch. Assumes // codegen and target are in thumb2 mode. // NOTE: native pointer. m2l_->LoadWordDisp(rs_rARM_SELF, func_offset.Int32Value(), rs_rARM_PC); } private: const bool restore_lr_; const size_t sp_displace_; }; if (large_frame) { // Note: may need a temp reg, and we only have r12 free at this point. OpRegRegImm(kOpSub, rs_rARM_LR, rs_rARM_SP, frame_size_without_spills); Load32Disp(rs_rARM_SELF, Thread::StackEndOffset<4>().Int32Value(), rs_r12); LIR* branch = OpCmpBranch(kCondUlt, rs_rARM_LR, rs_r12, nullptr); // Need to restore LR since we used it as a temp. AddSlowPath(new(arena_)StackOverflowSlowPath(this, branch, true, spill_size)); OpRegCopy(rs_rARM_SP, rs_rARM_LR); // Establish stack } else { /* * If the frame is small enough we are guaranteed to have enough space that remains to * handle signals on the user stack. However, we may not have any free temp * registers at this point, so we'll temporarily add LR to the temp pool. */ DCHECK(!GetRegInfo(rs_rARM_LR)->IsTemp()); MarkTemp(rs_rARM_LR); FreeTemp(rs_rARM_LR); OpRegRegImm(kOpSub, rs_rARM_SP, rs_rARM_SP, frame_size_without_spills); Clobber(rs_rARM_LR); UnmarkTemp(rs_rARM_LR); LIR* branch = OpCmpBranch(kCondUlt, rs_rARM_SP, rs_r12, nullptr); AddSlowPath(new(arena_)StackOverflowSlowPath(this, branch, false, frame_size_)); } } else { // Implicit stack overflow check has already been done. Just make room on the // stack for the frame now. OpRegImm(kOpSub, rs_rARM_SP, frame_size_without_spills); } } else { OpRegImm(kOpSub, rs_rARM_SP, frame_size_without_spills); } FlushIns(ArgLocs, rl_method); FreeTemp(rs_r0); FreeTemp(rs_r1); FreeTemp(rs_r2); FreeTemp(rs_r3); FreeTemp(rs_r12); } void ArmMir2Lir::GenExitSequence() { int spill_count = num_core_spills_ + num_fp_spills_; /* * In the exit path, r0/r1 are live - make sure they aren't * allocated by the register utilities as temps. */ LockTemp(rs_r0); LockTemp(rs_r1); NewLIR0(kPseudoMethodExit); OpRegImm(kOpAdd, rs_rARM_SP, frame_size_ - (spill_count * 4)); /* Need to restore any FP callee saves? */ if (num_fp_spills_) { NewLIR1(kThumb2VPopCS, num_fp_spills_); } if (core_spill_mask_ & (1 << rs_rARM_LR.GetRegNum())) { /* Unspill rARM_LR to rARM_PC */ core_spill_mask_ &= ~(1 << rs_rARM_LR.GetRegNum()); core_spill_mask_ |= (1 << rs_rARM_PC.GetRegNum()); } NewLIR1(kThumb2Pop, core_spill_mask_); if (!(core_spill_mask_ & (1 << rs_rARM_PC.GetRegNum()))) { /* We didn't pop to rARM_PC, so must do a bv rARM_LR */ NewLIR1(kThumbBx, rs_rARM_LR.GetReg()); } } void ArmMir2Lir::GenSpecialExitSequence() { NewLIR1(kThumbBx, rs_rARM_LR.GetReg()); } } // namespace art