// Copyright 2011 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "src/assembler-inl.h"
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#include "src/deoptimizer.h"
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#include "src/register-configuration.h"
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#include "src/safepoint-table.h"
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namespace v8 {
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namespace internal {
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#define __ masm()->
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// This code tries to be close to ia32 code so that any changes can be
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// easily ported.
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void Deoptimizer::TableEntryGenerator::Generate() {
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GeneratePrologue();
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// Unlike on ARM we don't save all the registers, just the useful ones.
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// For the rest, there are gaps on the stack, so the offsets remain the same.
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const int kNumberOfRegisters = Register::kNumRegisters;
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RegList restored_regs = kJSCallerSaved | kCalleeSaved;
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RegList saved_regs = restored_regs | sp.bit() | ra.bit();
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const int kDoubleRegsSize = kDoubleSize * DoubleRegister::kNumRegisters;
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const int kFloatRegsSize = kFloatSize * FloatRegister::kNumRegisters;
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// Save all double FPU registers before messing with them.
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__ Dsubu(sp, sp, Operand(kDoubleRegsSize));
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const RegisterConfiguration* config = RegisterConfiguration::Default();
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for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
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int code = config->GetAllocatableDoubleCode(i);
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const DoubleRegister fpu_reg = DoubleRegister::from_code(code);
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int offset = code * kDoubleSize;
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__ Sdc1(fpu_reg, MemOperand(sp, offset));
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}
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// Save all float FPU registers before messing with them.
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__ Dsubu(sp, sp, Operand(kFloatRegsSize));
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for (int i = 0; i < config->num_allocatable_float_registers(); ++i) {
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int code = config->GetAllocatableFloatCode(i);
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const FloatRegister fpu_reg = FloatRegister::from_code(code);
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int offset = code * kFloatSize;
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__ Swc1(fpu_reg, MemOperand(sp, offset));
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}
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// Push saved_regs (needed to populate FrameDescription::registers_).
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// Leave gaps for other registers.
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__ Dsubu(sp, sp, kNumberOfRegisters * kPointerSize);
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for (int16_t i = kNumberOfRegisters - 1; i >= 0; i--) {
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if ((saved_regs & (1 << i)) != 0) {
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__ Sd(ToRegister(i), MemOperand(sp, kPointerSize * i));
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}
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}
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__ li(a2, Operand(ExternalReference::Create(
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IsolateAddressId::kCEntryFPAddress, isolate())));
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__ Sd(fp, MemOperand(a2));
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const int kSavedRegistersAreaSize =
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(kNumberOfRegisters * kPointerSize) + kDoubleRegsSize + kFloatRegsSize;
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// Get the bailout id from the stack.
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__ Ld(a2, MemOperand(sp, kSavedRegistersAreaSize));
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// Get the address of the location in the code object (a3) (return
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// address for lazy deoptimization) and compute the fp-to-sp delta in
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// register a4.
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__ mov(a3, ra);
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// Correct one word for bailout id.
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__ Daddu(a4, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize)));
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__ Dsubu(a4, fp, a4);
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// Allocate a new deoptimizer object.
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__ PrepareCallCFunction(6, a5);
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// Pass six arguments, according to n64 ABI.
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__ mov(a0, zero_reg);
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Label context_check;
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__ Ld(a1, MemOperand(fp, CommonFrameConstants::kContextOrFrameTypeOffset));
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__ JumpIfSmi(a1, &context_check);
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__ Ld(a0, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
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__ bind(&context_check);
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__ li(a1, Operand(static_cast<int>(deopt_kind())));
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// a2: bailout id already loaded.
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// a3: code address or 0 already loaded.
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// a4: already has fp-to-sp delta.
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__ li(a5, Operand(ExternalReference::isolate_address(isolate())));
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// Call Deoptimizer::New().
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{
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AllowExternalCallThatCantCauseGC scope(masm());
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__ CallCFunction(ExternalReference::new_deoptimizer_function(), 6);
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}
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// Preserve "deoptimizer" object in register v0 and get the input
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// frame descriptor pointer to a1 (deoptimizer->input_);
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// Move deopt-obj to a0 for call to Deoptimizer::ComputeOutputFrames() below.
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__ mov(a0, v0);
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__ Ld(a1, MemOperand(v0, Deoptimizer::input_offset()));
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// Copy core registers into FrameDescription::registers_[kNumRegisters].
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DCHECK_EQ(Register::kNumRegisters, kNumberOfRegisters);
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for (int i = 0; i < kNumberOfRegisters; i++) {
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int offset = (i * kPointerSize) + FrameDescription::registers_offset();
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if ((saved_regs & (1 << i)) != 0) {
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__ Ld(a2, MemOperand(sp, i * kPointerSize));
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__ Sd(a2, MemOperand(a1, offset));
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} else if (FLAG_debug_code) {
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__ li(a2, kDebugZapValue);
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__ Sd(a2, MemOperand(a1, offset));
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}
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}
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int double_regs_offset = FrameDescription::double_registers_offset();
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// Copy FPU registers to
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// double_registers_[DoubleRegister::kNumAllocatableRegisters]
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for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
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int code = config->GetAllocatableDoubleCode(i);
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int dst_offset = code * kDoubleSize + double_regs_offset;
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int src_offset =
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code * kDoubleSize + kNumberOfRegisters * kPointerSize + kFloatRegsSize;
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__ Ldc1(f0, MemOperand(sp, src_offset));
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__ Sdc1(f0, MemOperand(a1, dst_offset));
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}
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int float_regs_offset = FrameDescription::float_registers_offset();
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// Copy FPU registers to
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// float_registers_[FloatRegister::kNumAllocatableRegisters]
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for (int i = 0; i < config->num_allocatable_float_registers(); ++i) {
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int code = config->GetAllocatableFloatCode(i);
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int dst_offset = code * kFloatSize + float_regs_offset;
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int src_offset = code * kFloatSize + kNumberOfRegisters * kPointerSize;
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__ Lwc1(f0, MemOperand(sp, src_offset));
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__ Swc1(f0, MemOperand(a1, dst_offset));
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}
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// Remove the bailout id and the saved registers from the stack.
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__ Daddu(sp, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize)));
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// Compute a pointer to the unwinding limit in register a2; that is
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// the first stack slot not part of the input frame.
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__ Ld(a2, MemOperand(a1, FrameDescription::frame_size_offset()));
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__ Daddu(a2, a2, sp);
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// Unwind the stack down to - but not including - the unwinding
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// limit and copy the contents of the activation frame to the input
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// frame description.
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__ Daddu(a3, a1, Operand(FrameDescription::frame_content_offset()));
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Label pop_loop;
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Label pop_loop_header;
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__ BranchShort(&pop_loop_header);
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__ bind(&pop_loop);
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__ pop(a4);
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__ Sd(a4, MemOperand(a3, 0));
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__ daddiu(a3, a3, sizeof(uint64_t));
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__ bind(&pop_loop_header);
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__ BranchShort(&pop_loop, ne, a2, Operand(sp));
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// Compute the output frame in the deoptimizer.
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__ push(a0); // Preserve deoptimizer object across call.
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// a0: deoptimizer object; a1: scratch.
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__ PrepareCallCFunction(1, a1);
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// Call Deoptimizer::ComputeOutputFrames().
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{
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AllowExternalCallThatCantCauseGC scope(masm());
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__ CallCFunction(ExternalReference::compute_output_frames_function(), 1);
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}
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__ pop(a0); // Restore deoptimizer object (class Deoptimizer).
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__ Ld(sp, MemOperand(a0, Deoptimizer::caller_frame_top_offset()));
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// Replace the current (input) frame with the output frames.
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Label outer_push_loop, inner_push_loop,
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outer_loop_header, inner_loop_header;
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// Outer loop state: a4 = current "FrameDescription** output_",
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// a1 = one past the last FrameDescription**.
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__ Lw(a1, MemOperand(a0, Deoptimizer::output_count_offset()));
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__ Ld(a4, MemOperand(a0, Deoptimizer::output_offset())); // a4 is output_.
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__ Dlsa(a1, a4, a1, kPointerSizeLog2);
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__ BranchShort(&outer_loop_header);
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__ bind(&outer_push_loop);
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// Inner loop state: a2 = current FrameDescription*, a3 = loop index.
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__ Ld(a2, MemOperand(a4, 0)); // output_[ix]
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__ Ld(a3, MemOperand(a2, FrameDescription::frame_size_offset()));
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__ BranchShort(&inner_loop_header);
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__ bind(&inner_push_loop);
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__ Dsubu(a3, a3, Operand(sizeof(uint64_t)));
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__ Daddu(a6, a2, Operand(a3));
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__ Ld(a7, MemOperand(a6, FrameDescription::frame_content_offset()));
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__ push(a7);
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__ bind(&inner_loop_header);
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__ BranchShort(&inner_push_loop, ne, a3, Operand(zero_reg));
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__ Daddu(a4, a4, Operand(kPointerSize));
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__ bind(&outer_loop_header);
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__ BranchShort(&outer_push_loop, lt, a4, Operand(a1));
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__ Ld(a1, MemOperand(a0, Deoptimizer::input_offset()));
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for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
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int code = config->GetAllocatableDoubleCode(i);
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const DoubleRegister fpu_reg = DoubleRegister::from_code(code);
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int src_offset = code * kDoubleSize + double_regs_offset;
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__ Ldc1(fpu_reg, MemOperand(a1, src_offset));
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}
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// Push pc and continuation from the last output frame.
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__ Ld(a6, MemOperand(a2, FrameDescription::pc_offset()));
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__ push(a6);
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__ Ld(a6, MemOperand(a2, FrameDescription::continuation_offset()));
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__ push(a6);
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// Technically restoring 'at' should work unless zero_reg is also restored
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// but it's safer to check for this.
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DCHECK(!(at.bit() & restored_regs));
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// Restore the registers from the last output frame.
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__ mov(at, a2);
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for (int i = kNumberOfRegisters - 1; i >= 0; i--) {
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int offset = (i * kPointerSize) + FrameDescription::registers_offset();
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if ((restored_regs & (1 << i)) != 0) {
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__ Ld(ToRegister(i), MemOperand(at, offset));
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}
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}
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__ InitializeRootRegister();
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__ pop(at); // Get continuation, leave pc on stack.
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__ pop(ra);
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__ Jump(at);
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__ stop("Unreachable.");
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}
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// Maximum size of a table entry generated below.
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#ifdef _MIPS_ARCH_MIPS64R6
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const int Deoptimizer::table_entry_size_ = 2 * kInstrSize;
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#else
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const int Deoptimizer::table_entry_size_ = 3 * kInstrSize;
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#endif
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void Deoptimizer::TableEntryGenerator::GeneratePrologue() {
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Assembler::BlockTrampolinePoolScope block_trampoline_pool(masm());
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// Create a sequence of deoptimization entries.
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// Note that registers are still live when jumping to an entry.
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Label table_start, done, trampoline_jump;
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__ bind(&table_start);
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#ifdef _MIPS_ARCH_MIPS64R6
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int kMaxEntriesBranchReach =
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(1 << (kImm26Bits - 2)) / (table_entry_size_ / kInstrSize);
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#else
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int kMaxEntriesBranchReach =
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(1 << (kImm16Bits - 2)) / (table_entry_size_ / kInstrSize);
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#endif
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if (count() <= kMaxEntriesBranchReach) {
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// Common case.
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for (int i = 0; i < count(); i++) {
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Label start;
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__ bind(&start);
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DCHECK(is_int16(i));
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if (kArchVariant == kMips64r6) {
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__ li(kScratchReg, i);
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__ BranchShort(PROTECT, &done);
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} else {
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__ BranchShort(USE_DELAY_SLOT, &done); // Expose delay slot.
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__ li(kScratchReg, i); // In the delay slot.
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__ nop();
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}
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DCHECK_EQ(table_entry_size_, masm()->SizeOfCodeGeneratedSince(&start));
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}
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DCHECK_EQ(masm()->SizeOfCodeGeneratedSince(&table_start),
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count() * table_entry_size_);
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__ bind(&done);
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__ Push(kScratchReg);
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} else {
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DCHECK_NE(kArchVariant, kMips64r6);
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// Uncommon case, the branch cannot reach.
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// Create mini trampoline to reach the end of the table
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for (int i = 0, j = 0; i < count(); i++, j++) {
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Label start;
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__ bind(&start);
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DCHECK(is_int16(i));
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if (j >= kMaxEntriesBranchReach) {
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j = 0;
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__ li(kScratchReg, i);
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__ bind(&trampoline_jump);
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trampoline_jump = Label();
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__ BranchShort(USE_DELAY_SLOT, &trampoline_jump);
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__ nop();
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} else {
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__ BranchShort(USE_DELAY_SLOT, &trampoline_jump); // Expose delay slot.
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__ li(kScratchReg, i); // In the delay slot.
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__ nop();
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}
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DCHECK_EQ(table_entry_size_, masm()->SizeOfCodeGeneratedSince(&start));
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}
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DCHECK_EQ(masm()->SizeOfCodeGeneratedSince(&table_start),
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count() * table_entry_size_);
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__ bind(&trampoline_jump);
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__ Push(kScratchReg);
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}
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}
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bool Deoptimizer::PadTopOfStackRegister() { return false; }
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void FrameDescription::SetCallerPc(unsigned offset, intptr_t value) {
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SetFrameSlot(offset, value);
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}
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void FrameDescription::SetCallerFp(unsigned offset, intptr_t value) {
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SetFrameSlot(offset, value);
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}
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void FrameDescription::SetCallerConstantPool(unsigned offset, intptr_t value) {
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// No embedded constant pool support.
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UNREACHABLE();
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}
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#undef __
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} // namespace internal
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} // namespace v8
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