// Copyright 2015, ARM Limited // All rights reserved. // // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions are met: // // * Redistributions of source code must retain the above copyright notice, // this list of conditions and the following disclaimer. // * Redistributions in binary form must reproduce the above copyright notice, // this list of conditions and the following disclaimer in the documentation // and/or other materials provided with the distribution. // * Neither the name of ARM Limited nor the names of its contributors may be // used to endorse or promote products derived from this software without // specific prior written permission. // // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND // ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED // WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. #include "jit/arm64/vixl/MacroAssembler-vixl.h" #include namespace vixl { MacroAssembler::MacroAssembler() : js::jit::Assembler(), sp_(x28), tmp_list_(ip0, ip1), fptmp_list_(d31) { } void MacroAssembler::FinalizeCode() { Assembler::FinalizeCode(); } int MacroAssembler::MoveImmediateHelper(MacroAssembler* masm, const Register &rd, uint64_t imm) { bool emit_code = (masm != NULL); VIXL_ASSERT(IsUint32(imm) || IsInt32(imm) || rd.Is64Bits()); // The worst case for size is mov 64-bit immediate to sp: // * up to 4 instructions to materialise the constant // * 1 instruction to move to sp MacroEmissionCheckScope guard(masm); // Immediates on Aarch64 can be produced using an initial value, and zero to // three move keep operations. // // Initial values can be generated with: // 1. 64-bit move zero (movz). // 2. 32-bit move inverted (movn). // 3. 64-bit move inverted. // 4. 32-bit orr immediate. // 5. 64-bit orr immediate. // Move-keep may then be used to modify each of the 16-bit half words. // // The code below supports all five initial value generators, and // applying move-keep operations to move-zero and move-inverted initial // values. // Try to move the immediate in one instruction, and if that fails, switch to // using multiple instructions. if (OneInstrMoveImmediateHelper(masm, rd, imm)) { return 1; } else { int instruction_count = 0; unsigned reg_size = rd.size(); // Generic immediate case. Imm will be represented by // [imm3, imm2, imm1, imm0], where each imm is 16 bits. // A move-zero or move-inverted is generated for the first non-zero or // non-0xffff immX, and a move-keep for subsequent non-zero immX. uint64_t ignored_halfword = 0; bool invert_move = false; // If the number of 0xffff halfwords is greater than the number of 0x0000 // halfwords, it's more efficient to use move-inverted. if (CountClearHalfWords(~imm, reg_size) > CountClearHalfWords(imm, reg_size)) { ignored_halfword = 0xffff; invert_move = true; } // Mov instructions can't move values into the stack pointer, so set up a // temporary register, if needed. UseScratchRegisterScope temps; Register temp; if (emit_code) { temps.Open(masm); temp = rd.IsSP() ? temps.AcquireSameSizeAs(rd) : rd; } // Iterate through the halfwords. Use movn/movz for the first non-ignored // halfword, and movk for subsequent halfwords. VIXL_ASSERT((reg_size % 16) == 0); bool first_mov_done = false; for (unsigned i = 0; i < (temp.size() / 16); i++) { uint64_t imm16 = (imm >> (16 * i)) & 0xffff; if (imm16 != ignored_halfword) { if (!first_mov_done) { if (invert_move) { if (emit_code) masm->movn(temp, ~imm16 & 0xffff, 16 * i); instruction_count++; } else { if (emit_code) masm->movz(temp, imm16, 16 * i); instruction_count++; } first_mov_done = true; } else { // Construct a wider constant. if (emit_code) masm->movk(temp, imm16, 16 * i); instruction_count++; } } } VIXL_ASSERT(first_mov_done); // Move the temporary if the original destination register was the stack // pointer. if (rd.IsSP()) { if (emit_code) masm->mov(rd, temp); instruction_count++; } return instruction_count; } } bool MacroAssembler::OneInstrMoveImmediateHelper(MacroAssembler* masm, const Register& dst, int64_t imm) { bool emit_code = masm != NULL; unsigned n, imm_s, imm_r; int reg_size = dst.size(); if (IsImmMovz(imm, reg_size) && !dst.IsSP()) { // Immediate can be represented in a move zero instruction. Movz can't write // to the stack pointer. if (emit_code) { masm->movz(dst, imm); } return true; } else if (IsImmMovn(imm, reg_size) && !dst.IsSP()) { // Immediate can be represented in a move negative instruction. Movn can't // write to the stack pointer. if (emit_code) { masm->movn(dst, dst.Is64Bits() ? ~imm : (~imm & kWRegMask)); } return true; } else if (IsImmLogical(imm, reg_size, &n, &imm_s, &imm_r)) { // Immediate can be represented in a logical orr instruction. VIXL_ASSERT(!dst.IsZero()); if (emit_code) { masm->LogicalImmediate( dst, AppropriateZeroRegFor(dst), n, imm_s, imm_r, ORR); } return true; } return false; } void MacroAssembler::B(Label* label, BranchType type, Register reg, int bit) { VIXL_ASSERT((reg.Is(NoReg) || (type >= kBranchTypeFirstUsingReg)) && ((bit == -1) || (type >= kBranchTypeFirstUsingBit))); if (kBranchTypeFirstCondition <= type && type <= kBranchTypeLastCondition) { B(static_cast(type), label); } else { switch (type) { case always: B(label); break; case never: break; case reg_zero: Cbz(reg, label); break; case reg_not_zero: Cbnz(reg, label); break; case reg_bit_clear: Tbz(reg, bit, label); break; case reg_bit_set: Tbnz(reg, bit, label); break; default: VIXL_UNREACHABLE(); } } } void MacroAssembler::B(Label* label) { SingleEmissionCheckScope guard(this); b(label); } void MacroAssembler::B(Label* label, Condition cond) { VIXL_ASSERT((cond != al) && (cond != nv)); EmissionCheckScope guard(this, 2 * kInstructionSize); if (label->bound() && LabelIsOutOfRange(label, CondBranchType)) { Label done; b(&done, InvertCondition(cond)); b(label); bind(&done); } else { b(label, cond); } } void MacroAssembler::Cbnz(const Register& rt, Label* label) { VIXL_ASSERT(!rt.IsZero()); EmissionCheckScope guard(this, 2 * kInstructionSize); if (label->bound() && LabelIsOutOfRange(label, CondBranchType)) { Label done; cbz(rt, &done); b(label); bind(&done); } else { cbnz(rt, label); } } void MacroAssembler::Cbz(const Register& rt, Label* label) { VIXL_ASSERT(!rt.IsZero()); EmissionCheckScope guard(this, 2 * kInstructionSize); if (label->bound() && LabelIsOutOfRange(label, CondBranchType)) { Label done; cbnz(rt, &done); b(label); bind(&done); } else { cbz(rt, label); } } void MacroAssembler::Tbnz(const Register& rt, unsigned bit_pos, Label* label) { VIXL_ASSERT(!rt.IsZero()); EmissionCheckScope guard(this, 2 * kInstructionSize); if (label->bound() && LabelIsOutOfRange(label, TestBranchType)) { Label done; tbz(rt, bit_pos, &done); b(label); bind(&done); } else { tbnz(rt, bit_pos, label); } } void MacroAssembler::Tbz(const Register& rt, unsigned bit_pos, Label* label) { VIXL_ASSERT(!rt.IsZero()); EmissionCheckScope guard(this, 2 * kInstructionSize); if (label->bound() && LabelIsOutOfRange(label, TestBranchType)) { Label done; tbnz(rt, bit_pos, &done); b(label); bind(&done); } else { tbz(rt, bit_pos, label); } } void MacroAssembler::And(const Register& rd, const Register& rn, const Operand& operand) { LogicalMacro(rd, rn, operand, AND); } void MacroAssembler::Ands(const Register& rd, const Register& rn, const Operand& operand) { LogicalMacro(rd, rn, operand, ANDS); } void MacroAssembler::Tst(const Register& rn, const Operand& operand) { Ands(AppropriateZeroRegFor(rn), rn, operand); } void MacroAssembler::Bic(const Register& rd, const Register& rn, const Operand& operand) { LogicalMacro(rd, rn, operand, BIC); } void MacroAssembler::Bics(const Register& rd, const Register& rn, const Operand& operand) { LogicalMacro(rd, rn, operand, BICS); } void MacroAssembler::Orr(const Register& rd, const Register& rn, const Operand& operand) { LogicalMacro(rd, rn, operand, ORR); } void MacroAssembler::Orn(const Register& rd, const Register& rn, const Operand& operand) { LogicalMacro(rd, rn, operand, ORN); } void MacroAssembler::Eor(const Register& rd, const Register& rn, const Operand& operand) { LogicalMacro(rd, rn, operand, EOR); } void MacroAssembler::Eon(const Register& rd, const Register& rn, const Operand& operand) { LogicalMacro(rd, rn, operand, EON); } void MacroAssembler::LogicalMacro(const Register& rd, const Register& rn, const Operand& operand, LogicalOp op) { // The worst case for size is logical immediate to sp: // * up to 4 instructions to materialise the constant // * 1 instruction to do the operation // * 1 instruction to move to sp MacroEmissionCheckScope guard(this); UseScratchRegisterScope temps(this); if (operand.IsImmediate()) { int64_t immediate = operand.immediate(); unsigned reg_size = rd.size(); // If the operation is NOT, invert the operation and immediate. if ((op & NOT) == NOT) { op = static_cast(op & ~NOT); immediate = ~immediate; } // Ignore the top 32 bits of an immediate if we're moving to a W register. if (rd.Is32Bits()) { // Check that the top 32 bits are consistent. VIXL_ASSERT(((immediate >> kWRegSize) == 0) || ((immediate >> kWRegSize) == -1)); immediate &= kWRegMask; } VIXL_ASSERT(rd.Is64Bits() || IsUint32(immediate)); // Special cases for all set or all clear immediates. if (immediate == 0) { switch (op) { case AND: Mov(rd, 0); return; case ORR: VIXL_FALLTHROUGH(); case EOR: Mov(rd, rn); return; case ANDS: VIXL_FALLTHROUGH(); case BICS: break; default: VIXL_UNREACHABLE(); } } else if ((rd.Is64Bits() && (immediate == -1)) || (rd.Is32Bits() && (immediate == 0xffffffff))) { switch (op) { case AND: Mov(rd, rn); return; case ORR: Mov(rd, immediate); return; case EOR: Mvn(rd, rn); return; case ANDS: VIXL_FALLTHROUGH(); case BICS: break; default: VIXL_UNREACHABLE(); } } unsigned n, imm_s, imm_r; if (IsImmLogical(immediate, reg_size, &n, &imm_s, &imm_r)) { // Immediate can be encoded in the instruction. LogicalImmediate(rd, rn, n, imm_s, imm_r, op); } else { // Immediate can't be encoded: synthesize using move immediate. Register temp = temps.AcquireSameSizeAs(rn); // If the left-hand input is the stack pointer, we can't pre-shift the // immediate, as the encoding won't allow the subsequent post shift. PreShiftImmMode mode = rn.IsSP() ? kNoShift : kAnyShift; Operand imm_operand = MoveImmediateForShiftedOp(temp, immediate, mode); // VIXL can acquire temp registers. Assert that the caller is aware. VIXL_ASSERT(!temp.Is(rd) && !temp.Is(rn)); VIXL_ASSERT(!temp.Is(operand.maybeReg())); if (rd.Is(sp)) { // If rd is the stack pointer we cannot use it as the destination // register so we use the temp register as an intermediate again. Logical(temp, rn, imm_operand, op); Mov(sp, temp); } else { Logical(rd, rn, imm_operand, op); } } } else if (operand.IsExtendedRegister()) { VIXL_ASSERT(operand.reg().size() <= rd.size()); // Add/sub extended supports shift <= 4. We want to support exactly the // same modes here. VIXL_ASSERT(operand.shift_amount() <= 4); VIXL_ASSERT(operand.reg().Is64Bits() || ((operand.extend() != UXTX) && (operand.extend() != SXTX))); temps.Exclude(operand.reg()); Register temp = temps.AcquireSameSizeAs(rn); // VIXL can acquire temp registers. Assert that the caller is aware. VIXL_ASSERT(!temp.Is(rd) && !temp.Is(rn)); VIXL_ASSERT(!temp.Is(operand.maybeReg())); EmitExtendShift(temp, operand.reg(), operand.extend(), operand.shift_amount()); Logical(rd, rn, Operand(temp), op); } else { // The operand can be encoded in the instruction. VIXL_ASSERT(operand.IsShiftedRegister()); Logical(rd, rn, operand, op); } } void MacroAssembler::Mov(const Register& rd, const Operand& operand, DiscardMoveMode discard_mode) { // The worst case for size is mov immediate with up to 4 instructions. MacroEmissionCheckScope guard(this); if (operand.IsImmediate()) { // Call the macro assembler for generic immediates. Mov(rd, operand.immediate()); } else if (operand.IsShiftedRegister() && (operand.shift_amount() != 0)) { // Emit a shift instruction if moving a shifted register. This operation // could also be achieved using an orr instruction (like orn used by Mvn), // but using a shift instruction makes the disassembly clearer. EmitShift(rd, operand.reg(), operand.shift(), operand.shift_amount()); } else if (operand.IsExtendedRegister()) { // Emit an extend instruction if moving an extended register. This handles // extend with post-shift operations, too. EmitExtendShift(rd, operand.reg(), operand.extend(), operand.shift_amount()); } else { // Otherwise, emit a register move only if the registers are distinct, or // if they are not X registers. // // Note that mov(w0, w0) is not a no-op because it clears the top word of // x0. A flag is provided (kDiscardForSameWReg) if a move between the same W // registers is not required to clear the top word of the X register. In // this case, the instruction is discarded. // // If the sp is an operand, add #0 is emitted, otherwise, orr #0. if (!rd.Is(operand.reg()) || (rd.Is32Bits() && (discard_mode == kDontDiscardForSameWReg))) { mov(rd, operand.reg()); } } } void MacroAssembler::Movi16bitHelper(const VRegister& vd, uint64_t imm) { VIXL_ASSERT(IsUint16(imm)); int byte1 = (imm & 0xff); int byte2 = ((imm >> 8) & 0xff); if (byte1 == byte2) { movi(vd.Is64Bits() ? vd.V8B() : vd.V16B(), byte1); } else if (byte1 == 0) { movi(vd, byte2, LSL, 8); } else if (byte2 == 0) { movi(vd, byte1); } else if (byte1 == 0xff) { mvni(vd, ~byte2 & 0xff, LSL, 8); } else if (byte2 == 0xff) { mvni(vd, ~byte1 & 0xff); } else { UseScratchRegisterScope temps(this); Register temp = temps.AcquireW(); movz(temp, imm); dup(vd, temp); } } void MacroAssembler::Movi32bitHelper(const VRegister& vd, uint64_t imm) { VIXL_ASSERT(IsUint32(imm)); uint8_t bytes[sizeof(imm)]; memcpy(bytes, &imm, sizeof(imm)); // All bytes are either 0x00 or 0xff. { bool all0orff = true; for (int i = 0; i < 4; ++i) { if ((bytes[i] != 0) && (bytes[i] != 0xff)) { all0orff = false; break; } } if (all0orff == true) { movi(vd.Is64Bits() ? vd.V1D() : vd.V2D(), ((imm << 32) | imm)); return; } } // Of the 4 bytes, only one byte is non-zero. for (int i = 0; i < 4; i++) { if ((imm & (0xff << (i * 8))) == imm) { movi(vd, bytes[i], LSL, i * 8); return; } } // Of the 4 bytes, only one byte is not 0xff. for (int i = 0; i < 4; i++) { uint32_t mask = ~(0xff << (i * 8)); if ((imm & mask) == mask) { mvni(vd, ~bytes[i] & 0xff, LSL, i * 8); return; } } // Immediate is of the form 0x00MMFFFF. if ((imm & 0xff00ffff) == 0x0000ffff) { movi(vd, bytes[2], MSL, 16); return; } // Immediate is of the form 0x0000MMFF. if ((imm & 0xffff00ff) == 0x000000ff) { movi(vd, bytes[1], MSL, 8); return; } // Immediate is of the form 0xFFMM0000. if ((imm & 0xff00ffff) == 0xff000000) { mvni(vd, ~bytes[2] & 0xff, MSL, 16); return; } // Immediate is of the form 0xFFFFMM00. if ((imm & 0xffff00ff) == 0xffff0000) { mvni(vd, ~bytes[1] & 0xff, MSL, 8); return; } // Top and bottom 16-bits are equal. if (((imm >> 16) & 0xffff) == (imm & 0xffff)) { Movi16bitHelper(vd.Is64Bits() ? vd.V4H() : vd.V8H(), imm & 0xffff); return; } // Default case. { UseScratchRegisterScope temps(this); Register temp = temps.AcquireW(); Mov(temp, imm); dup(vd, temp); } } void MacroAssembler::Movi64bitHelper(const VRegister& vd, uint64_t imm) { // All bytes are either 0x00 or 0xff. { bool all0orff = true; for (int i = 0; i < 8; ++i) { int byteval = (imm >> (i * 8)) & 0xff; if (byteval != 0 && byteval != 0xff) { all0orff = false; break; } } if (all0orff == true) { movi(vd, imm); return; } } // Top and bottom 32-bits are equal. if (((imm >> 32) & 0xffffffff) == (imm & 0xffffffff)) { Movi32bitHelper(vd.Is64Bits() ? vd.V2S() : vd.V4S(), imm & 0xffffffff); return; } // Default case. { UseScratchRegisterScope temps(this); Register temp = temps.AcquireX(); Mov(temp, imm); if (vd.Is1D()) { mov(vd.D(), 0, temp); } else { dup(vd.V2D(), temp); } } } void MacroAssembler::Movi(const VRegister& vd, uint64_t imm, Shift shift, int shift_amount) { MacroEmissionCheckScope guard(this); if (shift_amount != 0 || shift != LSL) { movi(vd, imm, shift, shift_amount); } else if (vd.Is8B() || vd.Is16B()) { // 8-bit immediate. VIXL_ASSERT(IsUint8(imm)); movi(vd, imm); } else if (vd.Is4H() || vd.Is8H()) { // 16-bit immediate. Movi16bitHelper(vd, imm); } else if (vd.Is2S() || vd.Is4S()) { // 32-bit immediate. Movi32bitHelper(vd, imm); } else { // 64-bit immediate. Movi64bitHelper(vd, imm); } } void MacroAssembler::Movi(const VRegister& vd, uint64_t hi, uint64_t lo) { VIXL_ASSERT(vd.Is128Bits()); UseScratchRegisterScope temps(this); // When hi == lo, the following generates good code. // // In situations where the constants are complex and hi != lo, the following // can turn into up to 10 instructions: 2*(mov + 3*movk + dup/insert). To do // any better, we could try to estimate whether splatting the high value and // updating the low value would generate fewer instructions than vice versa // (what we do now). // // (A PC-relative load from memory to the vector register (ADR + LD2) is going // to have fairly high latency but is fairly compact; not clear what the best // tradeoff is.) Movi(vd.V2D(), lo); if (hi != lo) { Register temp = temps.AcquireX(); Mov(temp, hi); Ins(vd.V2D(), 1, temp); } } void MacroAssembler::Mvn(const Register& rd, const Operand& operand) { // The worst case for size is mvn immediate with up to 4 instructions. MacroEmissionCheckScope guard(this); if (operand.IsImmediate()) { // Call the macro assembler for generic immediates. Mvn(rd, operand.immediate()); } else if (operand.IsExtendedRegister()) { UseScratchRegisterScope temps(this); temps.Exclude(operand.reg()); // Emit two instructions for the extend case. This differs from Mov, as // the extend and invert can't be achieved in one instruction. Register temp = temps.AcquireSameSizeAs(rd); // VIXL can acquire temp registers. Assert that the caller is aware. VIXL_ASSERT(!temp.Is(rd) && !temp.Is(operand.maybeReg())); EmitExtendShift(temp, operand.reg(), operand.extend(), operand.shift_amount()); mvn(rd, Operand(temp)); } else { // Otherwise, register and shifted register cases can be handled by the // assembler directly, using orn. mvn(rd, operand); } } void MacroAssembler::Mov(const Register& rd, uint64_t imm) { MoveImmediateHelper(this, rd, imm); } void MacroAssembler::Ccmp(const Register& rn, const Operand& operand, StatusFlags nzcv, Condition cond) { if (operand.IsImmediate() && (operand.immediate() < 0)) { ConditionalCompareMacro(rn, -operand.immediate(), nzcv, cond, CCMN); } else { ConditionalCompareMacro(rn, operand, nzcv, cond, CCMP); } } void MacroAssembler::Ccmn(const Register& rn, const Operand& operand, StatusFlags nzcv, Condition cond) { if (operand.IsImmediate() && (operand.immediate() < 0)) { ConditionalCompareMacro(rn, -operand.immediate(), nzcv, cond, CCMP); } else { ConditionalCompareMacro(rn, operand, nzcv, cond, CCMN); } } void MacroAssembler::ConditionalCompareMacro(const Register& rn, const Operand& operand, StatusFlags nzcv, Condition cond, ConditionalCompareOp op) { VIXL_ASSERT((cond != al) && (cond != nv)); // The worst case for size is ccmp immediate: // * up to 4 instructions to materialise the constant // * 1 instruction for ccmp MacroEmissionCheckScope guard(this); if ((operand.IsShiftedRegister() && (operand.shift_amount() == 0)) || (operand.IsImmediate() && IsImmConditionalCompare(operand.immediate()))) { // The immediate can be encoded in the instruction, or the operand is an // unshifted register: call the assembler. ConditionalCompare(rn, operand, nzcv, cond, op); } else { UseScratchRegisterScope temps(this); // The operand isn't directly supported by the instruction: perform the // operation on a temporary register. Register temp = temps.AcquireSameSizeAs(rn); VIXL_ASSERT(!temp.Is(rn) && !temp.Is(operand.maybeReg())); Mov(temp, operand); ConditionalCompare(rn, temp, nzcv, cond, op); } } void MacroAssembler::Csel(const Register& rd, const Register& rn, const Operand& operand, Condition cond) { VIXL_ASSERT(!rd.IsZero()); VIXL_ASSERT(!rn.IsZero()); VIXL_ASSERT((cond != al) && (cond != nv)); // The worst case for size is csel immediate: // * up to 4 instructions to materialise the constant // * 1 instruction for csel MacroEmissionCheckScope guard(this); if (operand.IsImmediate()) { // Immediate argument. Handle special cases of 0, 1 and -1 using zero // register. int64_t imm = operand.immediate(); Register zr = AppropriateZeroRegFor(rn); if (imm == 0) { csel(rd, rn, zr, cond); } else if (imm == 1) { csinc(rd, rn, zr, cond); } else if (imm == -1) { csinv(rd, rn, zr, cond); } else { UseScratchRegisterScope temps(this); Register temp = temps.AcquireSameSizeAs(rn); VIXL_ASSERT(!temp.Is(rd) && !temp.Is(rn)); VIXL_ASSERT(!temp.Is(operand.maybeReg())); Mov(temp, operand.immediate()); csel(rd, rn, temp, cond); } } else if (operand.IsShiftedRegister() && (operand.shift_amount() == 0)) { // Unshifted register argument. csel(rd, rn, operand.reg(), cond); } else { // All other arguments. UseScratchRegisterScope temps(this); Register temp = temps.AcquireSameSizeAs(rn); VIXL_ASSERT(!temp.Is(rd) && !temp.Is(rn)); VIXL_ASSERT(!temp.Is(operand.maybeReg())); Mov(temp, operand); csel(rd, rn, temp, cond); } } void MacroAssembler::Add(const Register& rd, const Register& rn, const Operand& operand, FlagsUpdate S) { if (operand.IsImmediate() && (operand.immediate() < 0) && IsImmAddSub(-operand.immediate())) { AddSubMacro(rd, rn, -operand.immediate(), S, SUB); } else { AddSubMacro(rd, rn, operand, S, ADD); } } void MacroAssembler::Adds(const Register& rd, const Register& rn, const Operand& operand) { Add(rd, rn, operand, SetFlags); } void MacroAssembler::Sub(const Register& rd, const Register& rn, const Operand& operand, FlagsUpdate S) { if (operand.IsImmediate() && (operand.immediate() < 0) && IsImmAddSub(-operand.immediate())) { AddSubMacro(rd, rn, -operand.immediate(), S, ADD); } else { AddSubMacro(rd, rn, operand, S, SUB); } } void MacroAssembler::Subs(const Register& rd, const Register& rn, const Operand& operand) { Sub(rd, rn, operand, SetFlags); } void MacroAssembler::Cmn(const Register& rn, const Operand& operand) { Adds(AppropriateZeroRegFor(rn), rn, operand); } void MacroAssembler::Cmp(const Register& rn, const Operand& operand) { Subs(AppropriateZeroRegFor(rn), rn, operand); } void MacroAssembler::Fcmp(const FPRegister& fn, double value, FPTrapFlags trap) { // The worst case for size is: // * 1 to materialise the constant, using literal pool if necessary // * 1 instruction for fcmp{e} MacroEmissionCheckScope guard(this); if (value != 0.0) { UseScratchRegisterScope temps(this); FPRegister tmp = temps.AcquireSameSizeAs(fn); VIXL_ASSERT(!tmp.Is(fn)); Fmov(tmp, value); FPCompareMacro(fn, tmp, trap); } else { FPCompareMacro(fn, value, trap); } } void MacroAssembler::Fcmpe(const FPRegister& fn, double value) { Fcmp(fn, value, EnableTrap); } void MacroAssembler::Fmov(VRegister vd, double imm) { // Floating point immediates are loaded through the literal pool. MacroEmissionCheckScope guard(this); if (vd.Is1S() || vd.Is2S() || vd.Is4S()) { Fmov(vd, static_cast(imm)); return; } VIXL_ASSERT(vd.Is1D() || vd.Is2D()); if (IsImmFP64(imm)) { fmov(vd, imm); } else { uint64_t rawbits = DoubleToRawbits(imm); if (vd.IsScalar()) { if (rawbits == 0) { fmov(vd, xzr); } else { Assembler::fImmPool64(vd, imm); } } else { // TODO: consider NEON support for load literal. Movi(vd, rawbits); } } } void MacroAssembler::Fmov(VRegister vd, float imm) { // Floating point immediates are loaded through the literal pool. MacroEmissionCheckScope guard(this); if (vd.Is1D() || vd.Is2D()) { Fmov(vd, static_cast(imm)); return; } VIXL_ASSERT(vd.Is1S() || vd.Is2S() || vd.Is4S()); if (IsImmFP32(imm)) { fmov(vd, imm); } else { uint32_t rawbits = FloatToRawbits(imm); if (vd.IsScalar()) { if (rawbits == 0) { fmov(vd, wzr); } else { Assembler::fImmPool32(vd, imm); } } else { // TODO: consider NEON support for load literal. Movi(vd, rawbits); } } } void MacroAssembler::Neg(const Register& rd, const Operand& operand) { if (operand.IsImmediate()) { Mov(rd, -operand.immediate()); } else { Sub(rd, AppropriateZeroRegFor(rd), operand); } } void MacroAssembler::Negs(const Register& rd, const Operand& operand) { Subs(rd, AppropriateZeroRegFor(rd), operand); } bool MacroAssembler::TryOneInstrMoveImmediate(const Register& dst, int64_t imm) { return OneInstrMoveImmediateHelper(this, dst, imm); } Operand MacroAssembler::MoveImmediateForShiftedOp(const Register& dst, int64_t imm, PreShiftImmMode mode) { int reg_size = dst.size(); // Encode the immediate in a single move instruction, if possible. if (TryOneInstrMoveImmediate(dst, imm)) { // The move was successful; nothing to do here. } else { // Pre-shift the immediate to the least-significant bits of the register. int shift_low = CountTrailingZeros(imm, reg_size); if (mode == kLimitShiftForSP) { // When applied to the stack pointer, the subsequent arithmetic operation // can use the extend form to shift left by a maximum of four bits. Right // shifts are not allowed, so we filter them out later before the new // immediate is tested. shift_low = std::min(shift_low, 4); } int64_t imm_low = imm >> shift_low; // Pre-shift the immediate to the most-significant bits of the register, // inserting set bits in the least-significant bits. int shift_high = CountLeadingZeros(imm, reg_size); int64_t imm_high = (imm << shift_high) | ((INT64_C(1) << shift_high) - 1); if ((mode != kNoShift) && TryOneInstrMoveImmediate(dst, imm_low)) { // The new immediate has been moved into the destination's low bits: // return a new leftward-shifting operand. return Operand(dst, LSL, shift_low); } else if ((mode == kAnyShift) && TryOneInstrMoveImmediate(dst, imm_high)) { // The new immediate has been moved into the destination's high bits: // return a new rightward-shifting operand. return Operand(dst, LSR, shift_high); } else { Mov(dst, imm); } } return Operand(dst); } void MacroAssembler::ComputeAddress(const Register& dst, const MemOperand& mem_op) { // We cannot handle pre-indexing or post-indexing. VIXL_ASSERT(mem_op.addrmode() == Offset); Register base = mem_op.base(); if (mem_op.IsImmediateOffset()) { Add(dst, base, mem_op.offset()); } else { VIXL_ASSERT(mem_op.IsRegisterOffset()); Register reg_offset = mem_op.regoffset(); Shift shift = mem_op.shift(); Extend extend = mem_op.extend(); if (shift == NO_SHIFT) { VIXL_ASSERT(extend != NO_EXTEND); Add(dst, base, Operand(reg_offset, extend, mem_op.shift_amount())); } else { VIXL_ASSERT(extend == NO_EXTEND); Add(dst, base, Operand(reg_offset, shift, mem_op.shift_amount())); } } } void MacroAssembler::AddSubMacro(const Register& rd, const Register& rn, const Operand& operand, FlagsUpdate S, AddSubOp op) { // Worst case is add/sub immediate: // * up to 4 instructions to materialise the constant // * 1 instruction for add/sub MacroEmissionCheckScope guard(this); if (operand.IsZero() && rd.Is(rn) && rd.Is64Bits() && rn.Is64Bits() && (S == LeaveFlags)) { // The instruction would be a nop. Avoid generating useless code. return; } if ((operand.IsImmediate() && !IsImmAddSub(operand.immediate())) || (rn.IsZero() && !operand.IsShiftedRegister()) || (operand.IsShiftedRegister() && (operand.shift() == ROR))) { UseScratchRegisterScope temps(this); Register temp = temps.AcquireSameSizeAs(rn); if (operand.IsImmediate()) { PreShiftImmMode mode = kAnyShift; // If the destination or source register is the stack pointer, we can // only pre-shift the immediate right by values supported in the add/sub // extend encoding. if (rd.IsSP()) { // If the destination is SP and flags will be set, we can't pre-shift // the immediate at all. mode = (S == SetFlags) ? kNoShift : kLimitShiftForSP; } else if (rn.IsSP()) { mode = kLimitShiftForSP; } Operand imm_operand = MoveImmediateForShiftedOp(temp, operand.immediate(), mode); AddSub(rd, rn, imm_operand, S, op); } else { Mov(temp, operand); AddSub(rd, rn, temp, S, op); } } else { AddSub(rd, rn, operand, S, op); } } void MacroAssembler::Adc(const Register& rd, const Register& rn, const Operand& operand) { AddSubWithCarryMacro(rd, rn, operand, LeaveFlags, ADC); } void MacroAssembler::Adcs(const Register& rd, const Register& rn, const Operand& operand) { AddSubWithCarryMacro(rd, rn, operand, SetFlags, ADC); } void MacroAssembler::Sbc(const Register& rd, const Register& rn, const Operand& operand) { AddSubWithCarryMacro(rd, rn, operand, LeaveFlags, SBC); } void MacroAssembler::Sbcs(const Register& rd, const Register& rn, const Operand& operand) { AddSubWithCarryMacro(rd, rn, operand, SetFlags, SBC); } void MacroAssembler::Ngc(const Register& rd, const Operand& operand) { Register zr = AppropriateZeroRegFor(rd); Sbc(rd, zr, operand); } void MacroAssembler::Ngcs(const Register& rd, const Operand& operand) { Register zr = AppropriateZeroRegFor(rd); Sbcs(rd, zr, operand); } void MacroAssembler::AddSubWithCarryMacro(const Register& rd, const Register& rn, const Operand& operand, FlagsUpdate S, AddSubWithCarryOp op) { VIXL_ASSERT(rd.size() == rn.size()); // Worst case is addc/subc immediate: // * up to 4 instructions to materialise the constant // * 1 instruction for add/sub MacroEmissionCheckScope guard(this); UseScratchRegisterScope temps(this); if (operand.IsImmediate() || (operand.IsShiftedRegister() && (operand.shift() == ROR))) { // Add/sub with carry (immediate or ROR shifted register.) Register temp = temps.AcquireSameSizeAs(rn); VIXL_ASSERT(!temp.Is(rd) && !temp.Is(rn) && !temp.Is(operand.maybeReg())); Mov(temp, operand); AddSubWithCarry(rd, rn, Operand(temp), S, op); } else if (operand.IsShiftedRegister() && (operand.shift_amount() != 0)) { // Add/sub with carry (shifted register). VIXL_ASSERT(operand.reg().size() == rd.size()); VIXL_ASSERT(operand.shift() != ROR); VIXL_ASSERT(IsUintN(rd.size() == kXRegSize ? kXRegSizeLog2 : kWRegSizeLog2, operand.shift_amount())); temps.Exclude(operand.reg()); Register temp = temps.AcquireSameSizeAs(rn); VIXL_ASSERT(!temp.Is(rd) && !temp.Is(rn) && !temp.Is(operand.maybeReg())); EmitShift(temp, operand.reg(), operand.shift(), operand.shift_amount()); AddSubWithCarry(rd, rn, Operand(temp), S, op); } else if (operand.IsExtendedRegister()) { // Add/sub with carry (extended register). VIXL_ASSERT(operand.reg().size() <= rd.size()); // Add/sub extended supports a shift <= 4. We want to support exactly the // same modes. VIXL_ASSERT(operand.shift_amount() <= 4); VIXL_ASSERT(operand.reg().Is64Bits() || ((operand.extend() != UXTX) && (operand.extend() != SXTX))); temps.Exclude(operand.reg()); Register temp = temps.AcquireSameSizeAs(rn); VIXL_ASSERT(!temp.Is(rd) && !temp.Is(rn) && !temp.Is(operand.maybeReg())); EmitExtendShift(temp, operand.reg(), operand.extend(), operand.shift_amount()); AddSubWithCarry(rd, rn, Operand(temp), S, op); } else { // The addressing mode is directly supported by the instruction. AddSubWithCarry(rd, rn, operand, S, op); } } #define DEFINE_FUNCTION(FN, REGTYPE, REG, OP) \ void MacroAssembler::FN(const REGTYPE REG, const MemOperand& addr) { \ LoadStoreMacro(REG, addr, OP); \ } LS_MACRO_LIST(DEFINE_FUNCTION) #undef DEFINE_FUNCTION void MacroAssembler::LoadStoreMacro(const CPURegister& rt, const MemOperand& addr, LoadStoreOp op) { // Worst case is ldr/str pre/post index: // * 1 instruction for ldr/str // * up to 4 instructions to materialise the constant // * 1 instruction to update the base MacroEmissionCheckScope guard(this); int64_t offset = addr.offset(); unsigned access_size = CalcLSDataSize(op); // Check if an immediate offset fits in the immediate field of the // appropriate instruction. If not, emit two instructions to perform // the operation. if (addr.IsImmediateOffset() && !IsImmLSScaled(offset, access_size) && !IsImmLSUnscaled(offset)) { // Immediate offset that can't be encoded using unsigned or unscaled // addressing modes. UseScratchRegisterScope temps(this); Register temp = temps.AcquireSameSizeAs(addr.base()); VIXL_ASSERT(!temp.Is(rt)); VIXL_ASSERT(!temp.Is(addr.base()) && !temp.Is(addr.regoffset())); Mov(temp, addr.offset()); LoadStore(rt, MemOperand(addr.base(), temp), op); } else if (addr.IsPostIndex() && !IsImmLSUnscaled(offset)) { // Post-index beyond unscaled addressing range. LoadStore(rt, MemOperand(addr.base()), op); Add(addr.base(), addr.base(), Operand(offset)); } else if (addr.IsPreIndex() && !IsImmLSUnscaled(offset)) { // Pre-index beyond unscaled addressing range. Add(addr.base(), addr.base(), Operand(offset)); LoadStore(rt, MemOperand(addr.base()), op); } else { // Encodable in one load/store instruction. LoadStore(rt, addr, op); } } #define DEFINE_FUNCTION(FN, REGTYPE, REG, REG2, OP) \ void MacroAssembler::FN(const REGTYPE REG, \ const REGTYPE REG2, \ const MemOperand& addr) { \ LoadStorePairMacro(REG, REG2, addr, OP); \ } LSPAIR_MACRO_LIST(DEFINE_FUNCTION) #undef DEFINE_FUNCTION void MacroAssembler::LoadStorePairMacro(const CPURegister& rt, const CPURegister& rt2, const MemOperand& addr, LoadStorePairOp op) { // TODO(all): Should we support register offset for load-store-pair? VIXL_ASSERT(!addr.IsRegisterOffset()); // Worst case is ldp/stp immediate: // * 1 instruction for ldp/stp // * up to 4 instructions to materialise the constant // * 1 instruction to update the base MacroEmissionCheckScope guard(this); int64_t offset = addr.offset(); unsigned access_size = CalcLSPairDataSize(op); // Check if the offset fits in the immediate field of the appropriate // instruction. If not, emit two instructions to perform the operation. if (IsImmLSPair(offset, access_size)) { // Encodable in one load/store pair instruction. LoadStorePair(rt, rt2, addr, op); } else { Register base = addr.base(); if (addr.IsImmediateOffset()) { UseScratchRegisterScope temps(this); Register temp = temps.AcquireSameSizeAs(base); Add(temp, base, offset); LoadStorePair(rt, rt2, MemOperand(temp), op); } else if (addr.IsPostIndex()) { LoadStorePair(rt, rt2, MemOperand(base), op); Add(base, base, offset); } else { VIXL_ASSERT(addr.IsPreIndex()); Add(base, base, offset); LoadStorePair(rt, rt2, MemOperand(base), op); } } } void MacroAssembler::Prfm(PrefetchOperation op, const MemOperand& addr) { MacroEmissionCheckScope guard(this); // There are no pre- or post-index modes for prfm. VIXL_ASSERT(addr.IsImmediateOffset() || addr.IsRegisterOffset()); // The access size is implicitly 8 bytes for all prefetch operations. unsigned size = kXRegSizeInBytesLog2; // Check if an immediate offset fits in the immediate field of the // appropriate instruction. If not, emit two instructions to perform // the operation. if (addr.IsImmediateOffset() && !IsImmLSScaled(addr.offset(), size) && !IsImmLSUnscaled(addr.offset())) { // Immediate offset that can't be encoded using unsigned or unscaled // addressing modes. UseScratchRegisterScope temps(this); Register temp = temps.AcquireSameSizeAs(addr.base()); Mov(temp, addr.offset()); Prefetch(op, MemOperand(addr.base(), temp)); } else { // Simple register-offsets are encodable in one instruction. Prefetch(op, addr); } } void MacroAssembler::PushStackPointer() { PrepareForPush(1, 8); // Pushing a stack pointer leads to implementation-defined // behavior, which may be surprising. In particular, // str x28, [x28, #-8]! // pre-decrements the stack pointer, storing the decremented value. // Additionally, sp is read as xzr in this context, so it cannot be pushed. // So we must use a scratch register. UseScratchRegisterScope temps(this); Register scratch = temps.AcquireX(); Mov(scratch, GetStackPointer64()); str(scratch, MemOperand(GetStackPointer64(), -8, PreIndex)); } void MacroAssembler::Push(const CPURegister& src0, const CPURegister& src1, const CPURegister& src2, const CPURegister& src3) { VIXL_ASSERT(AreSameSizeAndType(src0, src1, src2, src3)); VIXL_ASSERT(src0.IsValid()); int count = 1 + src1.IsValid() + src2.IsValid() + src3.IsValid(); int size = src0.SizeInBytes(); if (src0.Is(GetStackPointer64())) { VIXL_ASSERT(count == 1); VIXL_ASSERT(size == 8); PushStackPointer(); return; } PrepareForPush(count, size); PushHelper(count, size, src0, src1, src2, src3); } void MacroAssembler::Pop(const CPURegister& dst0, const CPURegister& dst1, const CPURegister& dst2, const CPURegister& dst3) { // It is not valid to pop into the same register more than once in one // instruction, not even into the zero register. VIXL_ASSERT(!AreAliased(dst0, dst1, dst2, dst3)); VIXL_ASSERT(AreSameSizeAndType(dst0, dst1, dst2, dst3)); VIXL_ASSERT(dst0.IsValid()); int count = 1 + dst1.IsValid() + dst2.IsValid() + dst3.IsValid(); int size = dst0.SizeInBytes(); PrepareForPop(count, size); PopHelper(count, size, dst0, dst1, dst2, dst3); } void MacroAssembler::PushCPURegList(CPURegList registers) { VIXL_ASSERT(!registers.Overlaps(*TmpList())); VIXL_ASSERT(!registers.Overlaps(*FPTmpList())); int reg_size = registers.RegisterSizeInBytes(); PrepareForPush(registers.Count(), reg_size); // Bump the stack pointer and store two registers at the bottom. int size = registers.TotalSizeInBytes(); const CPURegister& bottom_0 = registers.PopLowestIndex(); const CPURegister& bottom_1 = registers.PopLowestIndex(); if (bottom_0.IsValid() && bottom_1.IsValid()) { Stp(bottom_0, bottom_1, MemOperand(GetStackPointer64(), -size, PreIndex)); } else if (bottom_0.IsValid()) { Str(bottom_0, MemOperand(GetStackPointer64(), -size, PreIndex)); } int offset = 2 * reg_size; while (!registers.IsEmpty()) { const CPURegister& src0 = registers.PopLowestIndex(); const CPURegister& src1 = registers.PopLowestIndex(); if (src1.IsValid()) { Stp(src0, src1, MemOperand(GetStackPointer64(), offset)); } else { Str(src0, MemOperand(GetStackPointer64(), offset)); } offset += 2 * reg_size; } } void MacroAssembler::PopCPURegList(CPURegList registers) { VIXL_ASSERT(!registers.Overlaps(*TmpList())); VIXL_ASSERT(!registers.Overlaps(*FPTmpList())); int reg_size = registers.RegisterSizeInBytes(); PrepareForPop(registers.Count(), reg_size); int size = registers.TotalSizeInBytes(); const CPURegister& bottom_0 = registers.PopLowestIndex(); const CPURegister& bottom_1 = registers.PopLowestIndex(); int offset = 2 * reg_size; while (!registers.IsEmpty()) { const CPURegister& dst0 = registers.PopLowestIndex(); const CPURegister& dst1 = registers.PopLowestIndex(); if (dst1.IsValid()) { Ldp(dst0, dst1, MemOperand(GetStackPointer64(), offset)); } else { Ldr(dst0, MemOperand(GetStackPointer64(), offset)); } offset += 2 * reg_size; } // Load the two registers at the bottom and drop the stack pointer. if (bottom_0.IsValid() && bottom_1.IsValid()) { Ldp(bottom_0, bottom_1, MemOperand(GetStackPointer64(), size, PostIndex)); } else if (bottom_0.IsValid()) { Ldr(bottom_0, MemOperand(GetStackPointer64(), size, PostIndex)); } } void MacroAssembler::PushMultipleTimes(int count, Register src) { int size = src.SizeInBytes(); PrepareForPush(count, size); // Push up to four registers at a time if possible because if the current // stack pointer is sp and the register size is 32, registers must be pushed // in blocks of four in order to maintain the 16-byte alignment for sp. while (count >= 4) { PushHelper(4, size, src, src, src, src); count -= 4; } if (count >= 2) { PushHelper(2, size, src, src, NoReg, NoReg); count -= 2; } if (count == 1) { PushHelper(1, size, src, NoReg, NoReg, NoReg); count -= 1; } VIXL_ASSERT(count == 0); } void MacroAssembler::PushHelper(int count, int size, const CPURegister& src0, const CPURegister& src1, const CPURegister& src2, const CPURegister& src3) { // Ensure that we don't unintentionally modify scratch or debug registers. // Worst case for size is 2 stp. InstructionAccurateScope scope(this, 2, InstructionAccurateScope::kMaximumSize); VIXL_ASSERT(AreSameSizeAndType(src0, src1, src2, src3)); VIXL_ASSERT(size == src0.SizeInBytes()); // Pushing the stack pointer has unexpected behavior. See PushStackPointer(). VIXL_ASSERT(!src0.Is(GetStackPointer64()) && !src0.Is(sp)); VIXL_ASSERT(!src1.Is(GetStackPointer64()) && !src1.Is(sp)); VIXL_ASSERT(!src2.Is(GetStackPointer64()) && !src2.Is(sp)); VIXL_ASSERT(!src3.Is(GetStackPointer64()) && !src3.Is(sp)); // The JS engine should never push 4 bytes. VIXL_ASSERT(size >= 8); // When pushing multiple registers, the store order is chosen such that // Push(a, b) is equivalent to Push(a) followed by Push(b). switch (count) { case 1: VIXL_ASSERT(src1.IsNone() && src2.IsNone() && src3.IsNone()); str(src0, MemOperand(GetStackPointer64(), -1 * size, PreIndex)); break; case 2: VIXL_ASSERT(src2.IsNone() && src3.IsNone()); stp(src1, src0, MemOperand(GetStackPointer64(), -2 * size, PreIndex)); break; case 3: VIXL_ASSERT(src3.IsNone()); stp(src2, src1, MemOperand(GetStackPointer64(), -3 * size, PreIndex)); str(src0, MemOperand(GetStackPointer64(), 2 * size)); break; case 4: // Skip over 4 * size, then fill in the gap. This allows four W registers // to be pushed using sp, whilst maintaining 16-byte alignment for sp at // all times. stp(src3, src2, MemOperand(GetStackPointer64(), -4 * size, PreIndex)); stp(src1, src0, MemOperand(GetStackPointer64(), 2 * size)); break; default: VIXL_UNREACHABLE(); } } void MacroAssembler::PopHelper(int count, int size, const CPURegister& dst0, const CPURegister& dst1, const CPURegister& dst2, const CPURegister& dst3) { // Ensure that we don't unintentionally modify scratch or debug registers. // Worst case for size is 2 ldp. InstructionAccurateScope scope(this, 2, InstructionAccurateScope::kMaximumSize); VIXL_ASSERT(AreSameSizeAndType(dst0, dst1, dst2, dst3)); VIXL_ASSERT(size == dst0.SizeInBytes()); // When popping multiple registers, the load order is chosen such that // Pop(a, b) is equivalent to Pop(a) followed by Pop(b). switch (count) { case 1: VIXL_ASSERT(dst1.IsNone() && dst2.IsNone() && dst3.IsNone()); ldr(dst0, MemOperand(GetStackPointer64(), 1 * size, PostIndex)); break; case 2: VIXL_ASSERT(dst2.IsNone() && dst3.IsNone()); ldp(dst0, dst1, MemOperand(GetStackPointer64(), 2 * size, PostIndex)); break; case 3: VIXL_ASSERT(dst3.IsNone()); ldr(dst2, MemOperand(GetStackPointer64(), 2 * size)); ldp(dst0, dst1, MemOperand(GetStackPointer64(), 3 * size, PostIndex)); break; case 4: // Load the higher addresses first, then load the lower addresses and skip // the whole block in the second instruction. This allows four W registers // to be popped using sp, whilst maintaining 16-byte alignment for sp at // all times. ldp(dst2, dst3, MemOperand(GetStackPointer64(), 2 * size)); ldp(dst0, dst1, MemOperand(GetStackPointer64(), 4 * size, PostIndex)); break; default: VIXL_UNREACHABLE(); } } void MacroAssembler::PrepareForPush(int count, int size) { if (sp.Is(GetStackPointer64())) { // If the current stack pointer is sp, then it must be aligned to 16 bytes // on entry and the total size of the specified registers must also be a // multiple of 16 bytes. VIXL_ASSERT((count * size) % 16 == 0); } else { // Even if the current stack pointer is not the system stack pointer (sp), // the system stack pointer will still be modified in order to comply with // ABI rules about accessing memory below the system stack pointer. BumpSystemStackPointer(count * size); } } void MacroAssembler::PrepareForPop(int count, int size) { USE(count, size); if (sp.Is(GetStackPointer64())) { // If the current stack pointer is sp, then it must be aligned to 16 bytes // on entry and the total size of the specified registers must also be a // multiple of 16 bytes. VIXL_ASSERT((count * size) % 16 == 0); } } void MacroAssembler::Poke(const Register& src, const Operand& offset) { if (offset.IsImmediate()) { VIXL_ASSERT(offset.immediate() >= 0); } Str(src, MemOperand(GetStackPointer64(), offset)); } void MacroAssembler::Peek(const Register& dst, const Operand& offset) { if (offset.IsImmediate()) { VIXL_ASSERT(offset.immediate() >= 0); } Ldr(dst, MemOperand(GetStackPointer64(), offset)); } void MacroAssembler::Claim(const Operand& size) { if (size.IsZero()) { return; } if (size.IsImmediate()) { VIXL_ASSERT(size.immediate() > 0); if (sp.Is(GetStackPointer64())) { VIXL_ASSERT((size.immediate() % 16) == 0); } } Sub(GetStackPointer64(), GetStackPointer64(), size); // Make sure the real stack pointer reflects the claimed stack space. // We can't use stack memory below the stack pointer, it could be clobbered by // interupts and signal handlers. if (!sp.Is(GetStackPointer64())) { Mov(sp, GetStackPointer64()); } } void MacroAssembler::Drop(const Operand& size) { if (size.IsZero()) { return; } if (size.IsImmediate()) { VIXL_ASSERT(size.immediate() > 0); if (sp.Is(GetStackPointer64())) { VIXL_ASSERT((size.immediate() % 16) == 0); } } Add(GetStackPointer64(), GetStackPointer64(), size); } void MacroAssembler::PushCalleeSavedRegisters() { // Ensure that the macro-assembler doesn't use any scratch registers. // 10 stp will be emitted. // TODO(all): Should we use GetCalleeSaved and SavedFP. InstructionAccurateScope scope(this, 10); // This method must not be called unless the current stack pointer is sp. VIXL_ASSERT(sp.Is(GetStackPointer64())); MemOperand tos(sp, -2 * static_cast(kXRegSizeInBytes), PreIndex); stp(x29, x30, tos); stp(x27, x28, tos); stp(x25, x26, tos); stp(x23, x24, tos); stp(x21, x22, tos); stp(x19, x20, tos); stp(d14, d15, tos); stp(d12, d13, tos); stp(d10, d11, tos); stp(d8, d9, tos); } void MacroAssembler::PopCalleeSavedRegisters() { // Ensure that the macro-assembler doesn't use any scratch registers. // 10 ldp will be emitted. // TODO(all): Should we use GetCalleeSaved and SavedFP. InstructionAccurateScope scope(this, 10); // This method must not be called unless the current stack pointer is sp. VIXL_ASSERT(sp.Is(GetStackPointer64())); MemOperand tos(sp, 2 * kXRegSizeInBytes, PostIndex); ldp(d8, d9, tos); ldp(d10, d11, tos); ldp(d12, d13, tos); ldp(d14, d15, tos); ldp(x19, x20, tos); ldp(x21, x22, tos); ldp(x23, x24, tos); ldp(x25, x26, tos); ldp(x27, x28, tos); ldp(x29, x30, tos); } void MacroAssembler::LoadCPURegList(CPURegList registers, const MemOperand& src) { LoadStoreCPURegListHelper(kLoad, registers, src); } void MacroAssembler::StoreCPURegList(CPURegList registers, const MemOperand& dst) { LoadStoreCPURegListHelper(kStore, registers, dst); } void MacroAssembler::LoadStoreCPURegListHelper(LoadStoreCPURegListAction op, CPURegList registers, const MemOperand& mem) { // We do not handle pre-indexing or post-indexing. VIXL_ASSERT(!(mem.IsPreIndex() || mem.IsPostIndex())); VIXL_ASSERT(!registers.Overlaps(tmp_list_)); VIXL_ASSERT(!registers.Overlaps(fptmp_list_)); VIXL_ASSERT(!registers.IncludesAliasOf(sp)); UseScratchRegisterScope temps(this); MemOperand loc = BaseMemOperandForLoadStoreCPURegList(registers, mem, &temps); while (registers.Count() >= 2) { const CPURegister& dst0 = registers.PopLowestIndex(); const CPURegister& dst1 = registers.PopLowestIndex(); if (op == kStore) { Stp(dst0, dst1, loc); } else { VIXL_ASSERT(op == kLoad); Ldp(dst0, dst1, loc); } loc.AddOffset(2 * registers.RegisterSizeInBytes()); } if (!registers.IsEmpty()) { if (op == kStore) { Str(registers.PopLowestIndex(), loc); } else { VIXL_ASSERT(op == kLoad); Ldr(registers.PopLowestIndex(), loc); } } } MemOperand MacroAssembler::BaseMemOperandForLoadStoreCPURegList( const CPURegList& registers, const MemOperand& mem, UseScratchRegisterScope* scratch_scope) { // If necessary, pre-compute the base address for the accesses. if (mem.IsRegisterOffset()) { Register reg_base = scratch_scope->AcquireX(); ComputeAddress(reg_base, mem); return MemOperand(reg_base); } else if (mem.IsImmediateOffset()) { int reg_size = registers.RegisterSizeInBytes(); int total_size = registers.TotalSizeInBytes(); int64_t min_offset = mem.offset(); int64_t max_offset = mem.offset() + std::max(0, total_size - 2 * reg_size); if ((registers.Count() >= 2) && (!Assembler::IsImmLSPair(min_offset, WhichPowerOf2(reg_size)) || !Assembler::IsImmLSPair(max_offset, WhichPowerOf2(reg_size)))) { Register reg_base = scratch_scope->AcquireX(); ComputeAddress(reg_base, mem); return MemOperand(reg_base); } } return mem; } void MacroAssembler::BumpSystemStackPointer(const Operand& space) { VIXL_ASSERT(!sp.Is(GetStackPointer64())); // TODO: Several callers rely on this not using scratch registers, so we use // the assembler directly here. However, this means that large immediate // values of 'space' cannot be handled. InstructionAccurateScope scope(this, 1); sub(sp, GetStackPointer64(), space); } void MacroAssembler::Trace(TraceParameters parameters, TraceCommand command) { #ifdef JS_SIMULATOR_ARM64 // The arguments to the trace pseudo instruction need to be contiguous in // memory, so make sure we don't try to emit a literal pool. InstructionAccurateScope scope(this, kTraceLength / kInstructionSize); Label start; bind(&start); // Refer to simulator-a64.h for a description of the marker and its // arguments. hlt(kTraceOpcode); // VIXL_ASSERT(SizeOfCodeGeneratedSince(&start) == kTraceParamsOffset); dc32(parameters); // VIXL_ASSERT(SizeOfCodeGeneratedSince(&start) == kTraceCommandOffset); dc32(command); #else // Emit nothing on real hardware. USE(parameters, command); #endif } void MacroAssembler::Log(TraceParameters parameters) { #ifdef JS_SIMULATOR_ARM64 // The arguments to the log pseudo instruction need to be contiguous in // memory, so make sure we don't try to emit a literal pool. InstructionAccurateScope scope(this, kLogLength / kInstructionSize); Label start; bind(&start); // Refer to simulator-a64.h for a description of the marker and its // arguments. hlt(kLogOpcode); // VIXL_ASSERT(SizeOfCodeGeneratedSince(&start) == kLogParamsOffset); dc32(parameters); #else // Emit nothing on real hardware. USE(parameters); #endif } void MacroAssembler::EnableInstrumentation() { VIXL_ASSERT(!isprint(InstrumentStateEnable)); InstructionAccurateScope scope(this, 1); movn(xzr, InstrumentStateEnable); } void MacroAssembler::DisableInstrumentation() { VIXL_ASSERT(!isprint(InstrumentStateDisable)); InstructionAccurateScope scope(this, 1); movn(xzr, InstrumentStateDisable); } void MacroAssembler::AnnotateInstrumentation(const char* marker_name) { VIXL_ASSERT(strlen(marker_name) == 2); // We allow only printable characters in the marker names. Unprintable // characters are reserved for controlling features of the instrumentation. VIXL_ASSERT(isprint(marker_name[0]) && isprint(marker_name[1])); InstructionAccurateScope scope(this, 1); movn(xzr, (marker_name[1] << 8) | marker_name[0]); } void UseScratchRegisterScope::Open(MacroAssembler* masm) { VIXL_ASSERT(!initialised_); available_ = masm->TmpList(); availablefp_ = masm->FPTmpList(); old_available_ = available_->list(); old_availablefp_ = availablefp_->list(); VIXL_ASSERT(available_->type() == CPURegister::kRegister); VIXL_ASSERT(availablefp_->type() == CPURegister::kVRegister); #ifdef DEBUG initialised_ = true; #endif } void UseScratchRegisterScope::Close() { if (available_) { available_->set_list(old_available_); available_ = NULL; } if (availablefp_) { availablefp_->set_list(old_availablefp_); availablefp_ = NULL; } #ifdef DEBUG initialised_ = false; #endif } UseScratchRegisterScope::UseScratchRegisterScope(MacroAssembler* masm) { #ifdef DEBUG initialised_ = false; #endif Open(masm); } // This allows deferred (and optional) initialisation of the scope. UseScratchRegisterScope::UseScratchRegisterScope() : available_(NULL), availablefp_(NULL), old_available_(0), old_availablefp_(0) { #ifdef DEBUG initialised_ = false; #endif } UseScratchRegisterScope::~UseScratchRegisterScope() { Close(); } bool UseScratchRegisterScope::IsAvailable(const CPURegister& reg) const { return available_->IncludesAliasOf(reg) || availablefp_->IncludesAliasOf(reg); } Register UseScratchRegisterScope::AcquireSameSizeAs(const Register& reg) { int code = AcquireNextAvailable(available_).code(); return Register(code, reg.size()); } FPRegister UseScratchRegisterScope::AcquireSameSizeAs(const FPRegister& reg) { int code = AcquireNextAvailable(availablefp_).code(); return FPRegister(code, reg.size()); } void UseScratchRegisterScope::Release(const CPURegister& reg) { VIXL_ASSERT(initialised_); if (reg.IsRegister()) { ReleaseByCode(available_, reg.code()); } else if (reg.IsFPRegister()) { ReleaseByCode(availablefp_, reg.code()); } else { VIXL_ASSERT(reg.IsNone()); } } void UseScratchRegisterScope::Include(const CPURegList& list) { VIXL_ASSERT(initialised_); if (list.type() == CPURegister::kRegister) { // Make sure that neither sp nor xzr are included the list. IncludeByRegList(available_, list.list() & ~(xzr.Bit() | sp.Bit())); } else { VIXL_ASSERT(list.type() == CPURegister::kVRegister); IncludeByRegList(availablefp_, list.list()); } } void UseScratchRegisterScope::Include(const Register& reg1, const Register& reg2, const Register& reg3, const Register& reg4) { VIXL_ASSERT(initialised_); RegList include = reg1.Bit() | reg2.Bit() | reg3.Bit() | reg4.Bit(); // Make sure that neither sp nor xzr are included the list. include &= ~(xzr.Bit() | sp.Bit()); IncludeByRegList(available_, include); } void UseScratchRegisterScope::Include(const FPRegister& reg1, const FPRegister& reg2, const FPRegister& reg3, const FPRegister& reg4) { RegList include = reg1.Bit() | reg2.Bit() | reg3.Bit() | reg4.Bit(); IncludeByRegList(availablefp_, include); } void UseScratchRegisterScope::Exclude(const CPURegList& list) { if (list.type() == CPURegister::kRegister) { ExcludeByRegList(available_, list.list()); } else { VIXL_ASSERT(list.type() == CPURegister::kVRegister); ExcludeByRegList(availablefp_, list.list()); } } void UseScratchRegisterScope::Exclude(const Register& reg1, const Register& reg2, const Register& reg3, const Register& reg4) { RegList exclude = reg1.Bit() | reg2.Bit() | reg3.Bit() | reg4.Bit(); ExcludeByRegList(available_, exclude); } void UseScratchRegisterScope::Exclude(const FPRegister& reg1, const FPRegister& reg2, const FPRegister& reg3, const FPRegister& reg4) { RegList excludefp = reg1.Bit() | reg2.Bit() | reg3.Bit() | reg4.Bit(); ExcludeByRegList(availablefp_, excludefp); } void UseScratchRegisterScope::Exclude(const CPURegister& reg1, const CPURegister& reg2, const CPURegister& reg3, const CPURegister& reg4) { RegList exclude = 0; RegList excludefp = 0; const CPURegister regs[] = {reg1, reg2, reg3, reg4}; for (unsigned i = 0; i < (sizeof(regs) / sizeof(regs[0])); i++) { if (regs[i].IsRegister()) { exclude |= regs[i].Bit(); } else if (regs[i].IsFPRegister()) { excludefp |= regs[i].Bit(); } else { VIXL_ASSERT(regs[i].IsNone()); } } ExcludeByRegList(available_, exclude); ExcludeByRegList(availablefp_, excludefp); } void UseScratchRegisterScope::ExcludeAll() { ExcludeByRegList(available_, available_->list()); ExcludeByRegList(availablefp_, availablefp_->list()); } CPURegister UseScratchRegisterScope::AcquireNextAvailable( CPURegList* available) { VIXL_CHECK(!available->IsEmpty()); CPURegister result = available->PopLowestIndex(); VIXL_ASSERT(!AreAliased(result, xzr, sp)); return result; } void UseScratchRegisterScope::ReleaseByCode(CPURegList* available, int code) { ReleaseByRegList(available, static_cast(1) << code); } void UseScratchRegisterScope::ReleaseByRegList(CPURegList* available, RegList regs) { available->set_list(available->list() | regs); } void UseScratchRegisterScope::IncludeByRegList(CPURegList* available, RegList regs) { available->set_list(available->list() | regs); } void UseScratchRegisterScope::ExcludeByRegList(CPURegList* available, RegList exclude) { available->set_list(available->list() & ~exclude); } } // namespace vixl