Merge experimental/a64 to bleeding_edge.

src/a64/deoptimizer-a64.cc

+// Copyright 2013 the V8 project authors. 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 Google Inc. 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 AND 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 "v8.h"
+
+#include "codegen.h"
+#include "deoptimizer.h"
+#include "full-codegen.h"
+#include "safepoint-table.h"
+
+
+namespace v8 {
+namespace internal {
+
+
+int Deoptimizer::patch_size() {
+  // Size of the code used to patch lazy bailout points.
+  // Patching is done by Deoptimizer::DeoptimizeFunction.
+  return 4 * kInstructionSize;
+}
+
+
+
+void Deoptimizer::PatchCodeForDeoptimization(Isolate* isolate, Code* code) {
+  // Invalidate the relocation information, as it will become invalid by the
+  // code patching below, and is not needed any more.
+  code->InvalidateRelocation();
+
+  // For each LLazyBailout instruction insert a call to the corresponding
+  // deoptimization entry.
+  DeoptimizationInputData* deopt_data =
+      DeoptimizationInputData::cast(code->deoptimization_data());
+  Address code_start_address = code->instruction_start();
+#ifdef DEBUG
+  Address prev_call_address = NULL;
+#endif
+
+  for (int i = 0; i < deopt_data->DeoptCount(); i++) {
+    if (deopt_data->Pc(i)->value() == -1) continue;
+
+    Address call_address = code_start_address + deopt_data->Pc(i)->value();
+    Address deopt_entry = GetDeoptimizationEntry(isolate, i, LAZY);
+
+    PatchingAssembler patcher(call_address, patch_size() / kInstructionSize);
+    patcher.LoadLiteral(ip0, 2 * kInstructionSize);
+    patcher.blr(ip0);
+    patcher.dc64(reinterpret_cast<intptr_t>(deopt_entry));
+
+    ASSERT((prev_call_address == NULL) ||
+           (call_address >= prev_call_address + patch_size()));
+    ASSERT(call_address + patch_size() <= code->instruction_end());
+#ifdef DEBUG
+    prev_call_address = call_address;
+#endif
+  }
+}
+
+
+void Deoptimizer::FillInputFrame(Address tos, JavaScriptFrame* frame) {
+  // Set the register values. The values are not important as there are no
+  // callee saved registers in JavaScript frames, so all registers are
+  // spilled. Registers fp and sp are set to the correct values though.
+  for (int i = 0; i < Register::NumRegisters(); i++) {
+    input_->SetRegister(i, 0);
+  }
+
+  // TODO(all): Do we also need to set a value to csp?
+  input_->SetRegister(jssp.code(), reinterpret_cast<intptr_t>(frame->sp()));
+  input_->SetRegister(fp.code(), reinterpret_cast<intptr_t>(frame->fp()));
+
+  for (int i = 0; i < DoubleRegister::NumAllocatableRegisters(); i++) {
+    input_->SetDoubleRegister(i, 0.0);
+  }
+
+  // Fill the frame content from the actual data on the frame.
+  for (unsigned i = 0; i < input_->GetFrameSize(); i += kPointerSize) {
+    input_->SetFrameSlot(i, Memory::uint64_at(tos + i));
+  }
+}
+
+
+bool Deoptimizer::HasAlignmentPadding(JSFunction* function) {
+  // There is no dynamic alignment padding on A64 in the input frame.
+  return false;
+}
+
+
+void Deoptimizer::SetPlatformCompiledStubRegisters(
+    FrameDescription* output_frame, CodeStubInterfaceDescriptor* descriptor) {
+  ApiFunction function(descriptor->deoptimization_handler_);
+  ExternalReference xref(&function, ExternalReference::BUILTIN_CALL, isolate_);
+  intptr_t handler = reinterpret_cast<intptr_t>(xref.address());
+  int params = descriptor->GetHandlerParameterCount();
+  output_frame->SetRegister(x0.code(), params);
+  output_frame->SetRegister(x1.code(), handler);
+}
+
+
+void Deoptimizer::CopyDoubleRegisters(FrameDescription* output_frame) {
+  for (int i = 0; i < DoubleRegister::kMaxNumRegisters; ++i) {
+    double double_value = input_->GetDoubleRegister(i);
+    output_frame->SetDoubleRegister(i, double_value);
+  }
+}
+
+
+Code* Deoptimizer::NotifyStubFailureBuiltin() {
+  return isolate_->builtins()->builtin(Builtins::kNotifyStubFailureSaveDoubles);
+}
+
+
+#define __ masm()->
+
+void Deoptimizer::EntryGenerator::Generate() {
+  GeneratePrologue();
+
+  // TODO(all): This code needs to be revisited. We probably only need to save
+  // caller-saved registers here. Callee-saved registers can be stored directly
+  // in the input frame.
+
+  // Save all allocatable floating point registers.
+  CPURegList saved_fp_registers(CPURegister::kFPRegister, kDRegSize,
+                                0, FPRegister::NumAllocatableRegisters() - 1);
+  __ PushCPURegList(saved_fp_registers);
+
+  // We save all the registers expcept jssp, sp and lr.
+  CPURegList saved_registers(CPURegister::kRegister, kXRegSize, 0, 27);
+  saved_registers.Combine(fp);
+  __ PushCPURegList(saved_registers);
+
+  const int kSavedRegistersAreaSize =
+      (saved_registers.Count() * kXRegSizeInBytes) +
+      (saved_fp_registers.Count() * kDRegSizeInBytes);
+
+  // Floating point registers are saved on the stack above core registers.
+  const int kFPRegistersOffset = saved_registers.Count() * kXRegSizeInBytes;
+
+  // Get the bailout id from the stack.
+  Register bailout_id = x2;
+  __ Peek(bailout_id, kSavedRegistersAreaSize);
+
+  Register code_object = x3;
+  Register fp_to_sp = x4;
+  // Get the address of the location in the code object. This is the return
+  // address for lazy deoptimization.
+  __ Mov(code_object, lr);
+  // Compute the fp-to-sp delta, and correct one word for bailout id.
+  __ Add(fp_to_sp, masm()->StackPointer(),
+         kSavedRegistersAreaSize + (1 * kPointerSize));
+  __ Sub(fp_to_sp, fp, fp_to_sp);
+
+  // Allocate a new deoptimizer object.
+  __ Ldr(x0, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
+  __ Mov(x1, type());
+  // Following arguments are already loaded:
+  //  - x2: bailout id
+  //  - x3: code object address
+  //  - x4: fp-to-sp delta
+  __ Mov(x5, Operand(ExternalReference::isolate_address(isolate())));
+
+  {
+    // Call Deoptimizer::New().
+    AllowExternalCallThatCantCauseGC scope(masm());
+    __ CallCFunction(ExternalReference::new_deoptimizer_function(isolate()), 6);
+  }
+
+  // Preserve "deoptimizer" object in register x0.
+  Register deoptimizer = x0;
+
+  // Get the input frame descriptor pointer.
+  __ Ldr(x1, MemOperand(deoptimizer, Deoptimizer::input_offset()));
+
+  // Copy core registers into the input frame.
+  CPURegList copy_to_input = saved_registers;
+  for (int i = 0; i < saved_registers.Count(); i++) {
+    // TODO(all): Look for opportunities to optimize this by using ldp/stp.
+    __ Peek(x2, i * kPointerSize);
+    CPURegister current_reg = copy_to_input.PopLowestIndex();
+    int offset = (current_reg.code() * kPointerSize) +
+        FrameDescription::registers_offset();
+    __ Str(x2, MemOperand(x1, offset));
+  }
+
+  // Copy FP registers to the input frame.
+  for (int i = 0; i < saved_fp_registers.Count(); i++) {
+    // TODO(all): Look for opportunities to optimize this by using ldp/stp.
+    int dst_offset = FrameDescription::double_registers_offset() +
+        (i * kDoubleSize);
+    int src_offset = kFPRegistersOffset + (i * kDoubleSize);
+    __ Peek(x2, src_offset);
+    __ Str(x2, MemOperand(x1, dst_offset));
+  }
+
+  // Remove the bailout id and the saved registers from the stack.
+  __ Drop(1 + (kSavedRegistersAreaSize / kXRegSizeInBytes));
+
+  // Compute a pointer to the unwinding limit in register x2; that is
+  // the first stack slot not part of the input frame.
+  Register unwind_limit = x2;
+  __ Ldr(unwind_limit, MemOperand(x1, FrameDescription::frame_size_offset()));
+  __ Add(unwind_limit, unwind_limit, __ StackPointer());
+
+  // Unwind the stack down to - but not including - the unwinding
+  // limit and copy the contents of the activation frame to the input
+  // frame description.
+  __ Add(x3, x1, FrameDescription::frame_content_offset());
+  Label pop_loop;
+  Label pop_loop_header;
+  __ B(&pop_loop_header);
+  __ Bind(&pop_loop);
+  __ Pop(x4);
+  __ Str(x4, MemOperand(x3, kPointerSize, PostIndex));
+  __ Bind(&pop_loop_header);
+  __ Cmp(unwind_limit, __ StackPointer());
+  __ B(ne, &pop_loop);
+
+  // Compute the output frame in the deoptimizer.
+  __ Push(x0);  // Preserve deoptimizer object across call.
+
+  {
+    // Call Deoptimizer::ComputeOutputFrames().
+    AllowExternalCallThatCantCauseGC scope(masm());
+    __ CallCFunction(
+        ExternalReference::compute_output_frames_function(isolate()), 1);
+  }
+  __ Pop(x4);  // Restore deoptimizer object (class Deoptimizer).
+
+  // Replace the current (input) frame with the output frames.
+  Label outer_push_loop, inner_push_loop,
+      outer_loop_header, inner_loop_header;
+  __ Ldrsw(x1, MemOperand(x4, Deoptimizer::output_count_offset()));
+  __ Ldr(x0, MemOperand(x4, Deoptimizer::output_offset()));
+  __ Add(x1, x0, Operand(x1, LSL, kPointerSizeLog2));
+  __ B(&outer_loop_header);
+
+  __ Bind(&outer_push_loop);
+  Register current_frame = x2;
+  __ Ldr(current_frame, MemOperand(x0, 0));
+  __ Ldr(x3, MemOperand(current_frame, FrameDescription::frame_size_offset()));
+  __ B(&inner_loop_header);
+
+  __ Bind(&inner_push_loop);
+  __ Sub(x3, x3, kPointerSize);
+  __ Add(x6, current_frame, x3);
+  __ Ldr(x7, MemOperand(x6, FrameDescription::frame_content_offset()));
+  __ Push(x7);
+  __ Bind(&inner_loop_header);
+  __ Cbnz(x3, &inner_push_loop);
+
+  __ Add(x0, x0, kPointerSize);
+  __ Bind(&outer_loop_header);
+  __ Cmp(x0, x1);
+  __ B(lt, &outer_push_loop);
+
+  __ Ldr(x1, MemOperand(x4, Deoptimizer::input_offset()));
+  ASSERT(!saved_fp_registers.IncludesAliasOf(crankshaft_fp_scratch) &&
+         !saved_fp_registers.IncludesAliasOf(fp_zero) &&
+         !saved_fp_registers.IncludesAliasOf(fp_scratch));
+  int src_offset = FrameDescription::double_registers_offset();
+  while (!saved_fp_registers.IsEmpty()) {
+    const CPURegister reg = saved_fp_registers.PopLowestIndex();
+    __ Ldr(reg, MemOperand(x1, src_offset));
+    src_offset += kDoubleSize;
+  }
+
+  // Push state from the last output frame.
+  __ Ldr(x6, MemOperand(current_frame, FrameDescription::state_offset()));
+  __ Push(x6);
+
+  // TODO(all): ARM copies a lot (if not all) of the last output frame onto the
+  // stack, then pops it all into registers. Here, we try to load it directly
+  // into the relevant registers. Is this correct? If so, we should improve the
+  // ARM code.
+
+  // TODO(all): This code needs to be revisited, We probably don't need to
+  // restore all the registers as fullcodegen does not keep live values in
+  // registers (note that at least fp must be restored though).
+
+  // Restore registers from the last output frame.
+  // Note that lr is not in the list of saved_registers and will be restored
+  // later. We can use it to hold the address of last output frame while
+  // reloading the other registers.
+  ASSERT(!saved_registers.IncludesAliasOf(lr));
+  Register last_output_frame = lr;
+  __ Mov(last_output_frame, current_frame);
+
+  // We don't need to restore x7 as it will be clobbered later to hold the
+  // continuation address.
+  Register continuation = x7;
+  saved_registers.Remove(continuation);
+
+  while (!saved_registers.IsEmpty()) {
+    // TODO(all): Look for opportunities to optimize this by using ldp.
+    CPURegister current_reg = saved_registers.PopLowestIndex();
+    int offset = (current_reg.code() * kPointerSize) +
+        FrameDescription::registers_offset();
+    __ Ldr(current_reg, MemOperand(last_output_frame, offset));
+  }
+
+  __ Ldr(continuation, MemOperand(last_output_frame,
+                                  FrameDescription::continuation_offset()));
+  __ Ldr(lr, MemOperand(last_output_frame, FrameDescription::pc_offset()));
+  __ InitializeRootRegister();
+  __ Br(continuation);
+}
+
+
+// Size of an entry of the second level deopt table.
+// This is the code size generated by GeneratePrologue for one entry.
+const int Deoptimizer::table_entry_size_ = 2 * kInstructionSize;
+
+
+void Deoptimizer::TableEntryGenerator::GeneratePrologue() {
+  // Create a sequence of deoptimization entries.
+  // Note that registers are still live when jumping to an entry.
+  Label done;
+  {
+    InstructionAccurateScope scope(masm());
+
+    // The number of entry will never exceed kMaxNumberOfEntries.
+    // As long as kMaxNumberOfEntries is a valid 16 bits immediate you can use
+    // a movz instruction to load the entry id.
+    ASSERT(is_uint16(Deoptimizer::kMaxNumberOfEntries));
+
+    for (int i = 0; i < count(); i++) {
+      int start = masm()->pc_offset();
+      USE(start);
+      __ movz(masm()->Tmp0(), i);
+      __ b(&done);
+      ASSERT(masm()->pc_offset() - start == table_entry_size_);
+    }
+  }
+  __ Bind(&done);
+  // TODO(all): We need to add some kind of assertion to verify that Tmp0()
+  // is not clobbered by Push.
+  __ Push(masm()->Tmp0());
+}
+
+
+void FrameDescription::SetCallerPc(unsigned offset, intptr_t value) {
+  SetFrameSlot(offset, value);
+}
+
+
+void FrameDescription::SetCallerFp(unsigned offset, intptr_t value) {
+  SetFrameSlot(offset, value);
+}
+
+
+#undef __
+
+} }  // namespace v8::internal