PPC: [turbofan] Frame elision for code stubs.

src/compiler/ppc/code-generator-ppc.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/code-generator.h"
 
 #include "src/ast/scopes.h"
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/node-matchers.h"
@@ skipping 169 matching lines @@
   OutOfLineRecordWrite(CodeGenerator* gen, Register object, int32_t offset,
                        Register value, Register scratch0, Register scratch1,
                        RecordWriteMode mode)
       : OutOfLineCode(gen),
         object_(object),
         offset_(no_reg),
         offset_immediate_(offset),
         value_(value),
         scratch0_(scratch0),
         scratch1_(scratch1),
-        mode_(mode) {}
+        mode_(mode),
+        must_save_lr_(!gen->frame_access_state()->has_frame()) {}
 
   void Generate() final {
     if (mode_ > RecordWriteMode::kValueIsPointer) {
       __ JumpIfSmi(value_, exit());
     }
     __ CheckPageFlag(value_, scratch0_,
                      MemoryChunk::kPointersToHereAreInterestingMask, eq,
                      exit());
     RememberedSetAction const remembered_set_action =
         mode_ > RecordWriteMode::kValueIsMap ? EMIT_REMEMBERED_SET
                                              : OMIT_REMEMBERED_SET;
     SaveFPRegsMode const save_fp_mode =
         frame()->DidAllocateDoubleRegisters() ? kSaveFPRegs : kDontSaveFPRegs;
-    if (!frame()->needs_frame()) {
+    if (must_save_lr_) {
       // We need to save and restore lr if the frame was elided.
       __ mflr(scratch1_);
       __ Push(scratch1_);
     }
     RecordWriteStub stub(isolate(), object_, scratch0_, scratch1_,
                          remembered_set_action, save_fp_mode);
     if (offset_.is(no_reg)) {
       __ addi(scratch1_, object_, Operand(offset_immediate_));
     } else {
       DCHECK_EQ(0, offset_immediate_);
       __ add(scratch1_, object_, offset_);
     }
     __ CallStub(&stub);
-    if (!frame()->needs_frame()) {
+    if (must_save_lr_) {
       // We need to save and restore lr if the frame was elided.
       __ Pop(scratch1_);
       __ mtlr(scratch1_);
     }
   }
 
  private:
   Register const object_;
   Register const offset_;
   int32_t const offset_immediate_;  // Valid if offset_.is(no_reg).
   Register const value_;
   Register const scratch0_;
   Register const scratch1_;
   RecordWriteMode const mode_;
+  bool must_save_lr_;
 };
 
 
 Condition FlagsConditionToCondition(FlagsCondition condition, ArchOpcode op) {
   switch (condition) {
     case kEqual:
       return eq;
     case kNotEqual:
       return ne;
     case kSignedLessThan:
@@ skipping 420 matching lines @@
     Register value = i.InputRegister(3);                      \
     if (mode == kMode_MRI) {                                  \
       __ asm_instr(value, operand);                           \
     } else {                                                  \
       __ asm_instrx(value, operand);                          \
     }                                                         \
     __ bind(&done);                                           \
     DCHECK_EQ(LeaveRC, i.OutputRCBit());                      \
   } while (0)
 
+void CodeGenerator::AssembleDeconstructFrame() {
+  __ LeaveFrame(StackFrame::MANUAL);
+}
+
+void CodeGenerator::AssembleSetupStackPointer() {}
 
 void CodeGenerator::AssembleDeconstructActivationRecord(int stack_param_delta) {
   int sp_slot_delta = TailCallFrameStackSlotDelta(stack_param_delta);
   if (sp_slot_delta > 0) {
     __ Add(sp, sp, sp_slot_delta * kPointerSize, r0);
   }
   frame_access_state()->SetFrameAccessToDefault();
 }
 
 
 void CodeGenerator::AssemblePrepareTailCall(int stack_param_delta) {
   int sp_slot_delta = TailCallFrameStackSlotDelta(stack_param_delta);
   if (sp_slot_delta < 0) {
     __ Add(sp, sp, sp_slot_delta * kPointerSize, r0);
     frame_access_state()->IncreaseSPDelta(-sp_slot_delta);
   }
-  if (frame()->needs_frame()) {
+  if (frame_access_state()->has_frame()) {
     __ RestoreFrameStateForTailCall();
   }
   frame_access_state()->SetFrameAccessToSP();
 }
 
 void CodeGenerator::AssemblePopArgumentsAdaptorFrame(Register args_reg,
                                                      Register scratch1,
                                                      Register scratch2,
                                                      Register scratch3) {
   DCHECK(!AreAliased(args_reg, scratch1, scratch2, scratch3));
@@ skipping 160 matching lines @@
       break;
     case kArchStackPointer:
       __ mr(i.OutputRegister(), sp);
       DCHECK_EQ(LeaveRC, i.OutputRCBit());
       break;
     case kArchFramePointer:
       __ mr(i.OutputRegister(), fp);
       DCHECK_EQ(LeaveRC, i.OutputRCBit());
       break;
     case kArchParentFramePointer:
-      if (frame_access_state()->frame()->needs_frame()) {
+      if (frame_access_state()->has_frame()) {
         __ LoadP(i.OutputRegister(), MemOperand(fp, 0));
       } else {
         __ mr(i.OutputRegister(), fp);
       }
       break;
     case kArchTruncateDoubleToI:
       // TODO(mbrandy): move slow call to stub out of line.
       __ TruncateDoubleToI(i.OutputRegister(), i.InputDoubleRegister(0));
       DCHECK_EQ(LeaveRC, i.OutputRCBit());
       break;
@@ skipping 807 matching lines @@
       isolate(), deoptimization_id, bailout_type);
   // TODO(turbofan): We should be able to generate better code by sharing the
   // actual final call site and just bl'ing to it here, similar to what we do
   // in the lithium backend.
   __ Call(deopt_entry, RelocInfo::RUNTIME_ENTRY);
 }
 
 
 void CodeGenerator::AssemblePrologue() {
   CallDescriptor* descriptor = linkage()->GetIncomingDescriptor();
-  if (frame()->needs_frame()) {
+  if (frame_access_state()->has_frame()) {
     if (descriptor->IsCFunctionCall()) {
       __ function_descriptor();
       __ mflr(r0);
       if (FLAG_enable_embedded_constant_pool) {
         __ Push(r0, fp, kConstantPoolRegister);
         // Adjust FP to point to saved FP.
         __ subi(fp, sp, Operand(StandardFrameConstants::kConstantPoolOffset));
       } else {
         __ Push(r0, fp);
         __ mr(fp, sp);
       }
     } else if (descriptor->IsJSFunctionCall()) {
       __ Prologue(this->info()->GeneratePreagedPrologue(), ip);
     } else {
       StackFrame::Type type = info()->GetOutputStackFrameType();
-      if (!ABI_CALL_VIA_IP &&
-          info()->output_code_kind() == Code::WASM_FUNCTION) {
-        // TODO(mbrandy): Restrict only to the wasm wrapper case.
-        __ StubPrologue(type);
-      } else {
-        __ StubPrologue(type, ip);
-      }
+      // TODO(mbrandy): Detect cases where ip is the entrypoint (for
+      // efficient intialization of the constant pool pointer register).
+      __ StubPrologue(type);
     }
-  } else {
-    frame()->SetElidedFrameSizeInSlots(0);
   }
-  frame_access_state()->SetFrameAccessToDefault();
 
   int stack_shrink_slots = frame()->GetSpillSlotCount();
   if (info()->is_osr()) {
     // TurboFan OSR-compiled functions cannot be entered directly.
     __ Abort(kShouldNotDirectlyEnterOsrFunction);
 
     // Unoptimized code jumps directly to this entrypoint while the unoptimized
     // frame is still on the stack. Optimized code uses OSR values directly from
     // the unoptimized frame. Thus, all that needs to be done is to allocate the
     // remaining stack slots.
@@ skipping 48 matching lines @@
     __ MultiPop(saves);
   }
 
   // Restore double registers.
   const RegList double_saves = descriptor->CalleeSavedFPRegisters();
   if (double_saves != 0) {
     __ MultiPopDoubles(double_saves);
   }
 
   if (descriptor->IsCFunctionCall()) {
-    __ LeaveFrame(StackFrame::MANUAL, pop_count * kPointerSize);
-  } else if (frame()->needs_frame()) {
+    AssembleDeconstructFrame();
+  } else if (frame_access_state()->has_frame()) {
     // Canonicalize JSFunction return sites for now.
     if (return_label_.is_bound()) {
       __ b(&return_label_);
       return;
     } else {
       __ bind(&return_label_);
-      __ LeaveFrame(StackFrame::MANUAL, pop_count * kPointerSize);
+      AssembleDeconstructFrame();
     }
-  } else {
-    __ Drop(pop_count);

[Mircea Trofin, 2016/03/30 22:39:24]

What happened to the pop_count?

[MTBrandyberry, 2016/03/30 22:57:47]

Since we can no longer can pass it via AssembleDeconstructFrame to Leaveframe,
the adjustment is done in all cases by Ret below.

   }
-  __ Ret();
+  __ Ret(pop_count);
 }
 
 
 void CodeGenerator::AssembleMove(InstructionOperand* source,
                                  InstructionOperand* destination) {
   PPCOperandConverter g(this, nullptr);
   // Dispatch on the source and destination operand kinds.  Not all
   // combinations are possible.
   if (source->IsRegister()) {
     DCHECK(destination->IsRegister() || destination->IsStackSlot());
@@ skipping 193 matching lines @@
       padding_size -= v8::internal::Assembler::kInstrSize;
     }
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8