X87: [crankshaft] [ia32] Remove dynamic frame alignment optimization.

  port fcb83f20(r34273)

  original commit message:
  This optimization does not give us much (see perf try bot results associated with this CL) but complicates things a lot. The main motivation is to avoid additional complexity in tail call optim

  There are some pieces left in the deoptimizer, but I'll address this in a separate CL.

BUG=

Review URL: https://codereview.chromium.org/1750433002

Cr-Commit-Position: refs/heads/master@{#34353}

src/crankshaft/x87/lithium-codegen-x87.cc

@@ -57,13 +57,6 @@ bool LCodeGen::GenerateCode() {
   // the frame (that is done in GeneratePrologue).
   FrameScope frame_scope(masm_, StackFrame::MANUAL);
 
-  support_aligned_spilled_doubles_ = info()->IsOptimizing();
-
-  dynamic_frame_alignment_ = info()->IsOptimizing() &&
-      ((chunk()->num_double_slots() > 2 &&
-        !chunk()->graph()->is_recursive()) ||
-       !info()->osr_ast_id().IsNone());
-
   return GeneratePrologue() &&
       GenerateBody() &&
       GenerateDeferredCode() &&
@@ -98,31 +91,6 @@ bool LCodeGen::GeneratePrologue() {
 
   if (info()->IsOptimizing()) {
     ProfileEntryHookStub::MaybeCallEntryHook(masm_);
-
-    if (support_aligned_spilled_doubles_ && dynamic_frame_alignment_) {
-      // Move state of dynamic frame alignment into edx.
-      __ Move(edx, Immediate(kNoAlignmentPadding));
-
-      Label do_not_pad, align_loop;
-      STATIC_ASSERT(kDoubleSize == 2 * kPointerSize);
-      // Align esp + 4 to a multiple of 2 * kPointerSize.
-      __ test(esp, Immediate(kPointerSize));
-      __ j(not_zero, &do_not_pad, Label::kNear);
-      __ push(Immediate(0));
-      __ mov(ebx, esp);
-      __ mov(edx, Immediate(kAlignmentPaddingPushed));
-      // Copy arguments, receiver, and return address.
-      __ mov(ecx, Immediate(scope()->num_parameters() + 2));
-
-      __ bind(&align_loop);
-      __ mov(eax, Operand(ebx, 1 * kPointerSize));
-      __ mov(Operand(ebx, 0), eax);
-      __ add(Operand(ebx), Immediate(kPointerSize));
-      __ dec(ecx);
-      __ j(not_zero, &align_loop, Label::kNear);
-      __ mov(Operand(ebx, 0), Immediate(kAlignmentZapValue));
-      __ bind(&do_not_pad);
-    }
   }
 
   info()->set_prologue_offset(masm_->pc_offset());
@@ -136,55 +104,23 @@ bool LCodeGen::GeneratePrologue() {
     }
   }
 
-  if (info()->IsOptimizing() &&
-      dynamic_frame_alignment_ &&
-      FLAG_debug_code) {
-    __ test(esp, Immediate(kPointerSize));
-    __ Assert(zero, kFrameIsExpectedToBeAligned);
-  }
-
   // Reserve space for the stack slots needed by the code.
   int slots = GetStackSlotCount();
   DCHECK(slots != 0 || !info()->IsOptimizing());
   if (slots > 0) {
-    if (slots == 1) {
-      if (dynamic_frame_alignment_) {
-        __ push(edx);
-      } else {
-        __ push(Immediate(kNoAlignmentPadding));
-      }
-    } else {
-      if (FLAG_debug_code) {
-        __ sub(Operand(esp), Immediate(slots * kPointerSize));
+    __ sub(Operand(esp), Immediate(slots * kPointerSize));
 #ifdef _MSC_VER
-        MakeSureStackPagesMapped(slots * kPointerSize);
+    MakeSureStackPagesMapped(slots * kPointerSize);
 #endif
-        __ push(eax);
-        __ mov(Operand(eax), Immediate(slots));
-        Label loop;
-        __ bind(&loop);
-        __ mov(MemOperand(esp, eax, times_4, 0),
-               Immediate(kSlotsZapValue));
-        __ dec(eax);
-        __ j(not_zero, &loop);
-        __ pop(eax);
-      } else {
-        __ sub(Operand(esp), Immediate(slots * kPointerSize));
-#ifdef _MSC_VER
-        MakeSureStackPagesMapped(slots * kPointerSize);
-#endif
-      }
-
-      if (support_aligned_spilled_doubles_) {
-        Comment(";;; Store dynamic frame alignment tag for spilled doubles");
-        // Store dynamic frame alignment state in the first local.
-        int offset = JavaScriptFrameConstants::kDynamicAlignmentStateOffset;
-        if (dynamic_frame_alignment_) {
-          __ mov(Operand(ebp, offset), edx);
-        } else {
-          __ mov(Operand(ebp, offset), Immediate(kNoAlignmentPadding));
-        }
-      }
+    if (FLAG_debug_code) {
+      __ push(eax);
+      __ mov(Operand(eax), Immediate(slots));
+      Label loop;
+      __ bind(&loop);
+      __ mov(MemOperand(esp, eax, times_4, 0), Immediate(kSlotsZapValue));
+      __ dec(eax);
+      __ j(not_zero, &loop);
+      __ pop(eax);
     }
   }
 
@@ -265,50 +201,11 @@ void LCodeGen::GenerateOsrPrologue() {
 
   osr_pc_offset_ = masm()->pc_offset();
 
-    // Move state of dynamic frame alignment into edx.
-  __ Move(edx, Immediate(kNoAlignmentPadding));
-
-  if (support_aligned_spilled_doubles_ && dynamic_frame_alignment_) {
-    Label do_not_pad, align_loop;
-    // Align ebp + 4 to a multiple of 2 * kPointerSize.
-    __ test(ebp, Immediate(kPointerSize));
-    __ j(zero, &do_not_pad, Label::kNear);
-    __ push(Immediate(0));
-    __ mov(ebx, esp);
-    __ mov(edx, Immediate(kAlignmentPaddingPushed));
-
-    // Move all parts of the frame over one word. The frame consists of:
-    // unoptimized frame slots, alignment state, context, frame pointer, return
-    // address, receiver, and the arguments.
-    __ mov(ecx, Immediate(scope()->num_parameters() +
-           5 + graph()->osr()->UnoptimizedFrameSlots()));
-
-    __ bind(&align_loop);
-    __ mov(eax, Operand(ebx, 1 * kPointerSize));
-    __ mov(Operand(ebx, 0), eax);
-    __ add(Operand(ebx), Immediate(kPointerSize));
-    __ dec(ecx);
-    __ j(not_zero, &align_loop, Label::kNear);
-    __ mov(Operand(ebx, 0), Immediate(kAlignmentZapValue));
-    __ sub(Operand(ebp), Immediate(kPointerSize));
-    __ bind(&do_not_pad);
-  }
-
-  // Save the first local, which is overwritten by the alignment state.
-  Operand alignment_loc = MemOperand(ebp, -3 * kPointerSize);
-  __ push(alignment_loc);
-
-  // Set the dynamic frame alignment state.
-  __ mov(alignment_loc, edx);
-
   // Adjust the frame size, subsuming the unoptimized frame into the
   // optimized frame.
   int slots = GetStackSlotCount() - graph()->osr()->UnoptimizedFrameSlots();
-  DCHECK(slots >= 1);
-  __ sub(esp, Immediate((slots - 1) * kPointerSize));
-
-  // Initailize FPU state.
-  __ fninit();
+  DCHECK(slots >= 0);
+  __ sub(esp, Immediate(slots * kPointerSize));
 }
 
 
@@ -2749,18 +2646,11 @@ void LCodeGen::DoCmpT(LCmpT* instr) {
   __ bind(&done);
 }
 
-
-void LCodeGen::EmitReturn(LReturn* instr, bool dynamic_frame_alignment) {
-  int extra_value_count = dynamic_frame_alignment ? 2 : 1;
+void LCodeGen::EmitReturn(LReturn* instr) {
+  int extra_value_count = 1;
 
   if (instr->has_constant_parameter_count()) {
     int parameter_count = ToInteger32(instr->constant_parameter_count());
-    if (dynamic_frame_alignment && FLAG_debug_code) {
-      __ cmp(Operand(esp,
-                     (parameter_count + extra_value_count) * kPointerSize),
-             Immediate(kAlignmentZapValue));
-      __ Assert(equal, kExpectedAlignmentMarker);
-    }
     __ Ret((parameter_count + extra_value_count) * kPointerSize, ecx);
   } else {
     DCHECK(info()->IsStub());  // Functions would need to drop one more value.
@@ -2768,19 +2658,9 @@ void LCodeGen::EmitReturn(LReturn* instr, bool dynamic_frame_alignment) {
     // The argument count parameter is a smi
     __ SmiUntag(reg);
     Register return_addr_reg = reg.is(ecx) ? ebx : ecx;
-    if (dynamic_frame_alignment && FLAG_debug_code) {
-      DCHECK(extra_value_count == 2);
-      __ cmp(Operand(esp, reg, times_pointer_size,
-                     extra_value_count * kPointerSize),
-             Immediate(kAlignmentZapValue));
-      __ Assert(equal, kExpectedAlignmentMarker);
-    }
 
     // emit code to restore stack based on instr->parameter_count()
     __ pop(return_addr_reg);  // save return address
-    if (dynamic_frame_alignment) {
-      __ inc(reg);  // 1 more for alignment
-    }
     __ shl(reg, kPointerSizeLog2);
     __ add(esp, reg);
     __ jmp(return_addr_reg);
@@ -2798,25 +2678,12 @@ void LCodeGen::DoReturn(LReturn* instr) {
     __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
     __ CallRuntime(Runtime::kTraceExit);
   }
-  if (dynamic_frame_alignment_) {
-    // Fetch the state of the dynamic frame alignment.
-    __ mov(edx, Operand(ebp,
-      JavaScriptFrameConstants::kDynamicAlignmentStateOffset));
-  }
   if (NeedsEagerFrame()) {
     __ mov(esp, ebp);
     __ pop(ebp);
   }
-  if (dynamic_frame_alignment_) {
-    Label no_padding;
-    __ cmp(edx, Immediate(kNoAlignmentPadding));
-    __ j(equal, &no_padding, Label::kNear);
-
-    EmitReturn(instr, true);
-    __ bind(&no_padding);
-  }
 
-  EmitReturn(instr, false);
+  EmitReturn(instr);
 }
 
 

src/crankshaft/x87/lithium-codegen-x87.h

@@ -31,8 +31,6 @@ class LCodeGen: public LCodeGenBase {
         jump_table_(4, info->zone()),
         scope_(info->scope()),
         deferred_(8, info->zone()),
-        dynamic_frame_alignment_(false),
-        support_aligned_spilled_doubles_(false),
         frame_is_built_(false),
         x87_stack_(assembler),
         safepoints_(info->zone()),
@@ -329,7 +327,7 @@ class LCodeGen: public LCodeGenBase {
   template <class T>
   void EmitVectorStoreICRegisters(T* instr);
 
-  void EmitReturn(LReturn* instr, bool dynamic_frame_alignment);
+  void EmitReturn(LReturn* instr);
 
   // Emits code for pushing either a tagged constant, a (non-double)
   // register, or a stack slot operand.
@@ -354,8 +352,6 @@ class LCodeGen: public LCodeGenBase {
   ZoneList<Deoptimizer::JumpTableEntry> jump_table_;
   Scope* const scope_;
   ZoneList<LDeferredCode*> deferred_;
-  bool dynamic_frame_alignment_;
-  bool support_aligned_spilled_doubles_;
   bool frame_is_built_;
 
   class X87Stack : public ZoneObject {

src/crankshaft/x87/lithium-x87.cc

@@ -424,13 +424,6 @@ LPlatformChunk* LChunkBuilder::Build() {
   LPhase phase("L_Building chunk", chunk_);
   status_ = BUILDING;
 
-  // Reserve the first spill slot for the state of dynamic alignment.
-  if (info()->IsOptimizing()) {
-    int alignment_state_index = chunk_->GetNextSpillIndex(GENERAL_REGISTERS);
-    DCHECK_EQ(alignment_state_index, 4);
-    USE(alignment_state_index);
-  }
-
   // If compiling for OSR, reserve space for the unoptimized frame,
   // which will be subsumed into this frame.
   if (graph()->has_osr()) {
@@ -2465,11 +2458,6 @@ LInstruction* LChunkBuilder::DoUnknownOSRValue(HUnknownOSRValue* instr) {
       Retry(kNotEnoughSpillSlotsForOsr);
       spill_index = 0;
     }
-    if (spill_index == 0) {
-      // The dynamic frame alignment state overwrites the first local.
-      // The first local is saved at the end of the unoptimized frame.
-      spill_index = graph()->osr()->UnoptimizedFrameSlots();
-    }
     spill_index += StandardFrameConstants::kFixedSlotCount;
   }
   return DefineAsSpilled(new(zone()) LUnknownOSRValue, spill_index);

src/x87/deoptimizer-x87.cc

@@ -187,16 +187,8 @@ void Deoptimizer::CopyDoubleRegisters(FrameDescription* output_frame) {
 }
 
 bool Deoptimizer::HasAlignmentPadding(SharedFunctionInfo* shared) {
-  int parameter_count = shared->internal_formal_parameter_count() + 1;
-  unsigned input_frame_size = input_->GetFrameSize();
-  unsigned alignment_state_offset =
-      input_frame_size - parameter_count * kPointerSize -
-      StandardFrameConstants::kFixedFrameSize -
-      kPointerSize;
-  DCHECK(JavaScriptFrameConstants::kDynamicAlignmentStateOffset ==
-      JavaScriptFrameConstants::kLocal0Offset);
-  int32_t alignment_state = input_->GetFrameSlot(alignment_state_offset);
-  return (alignment_state == kAlignmentPaddingPushed);
+  // There is no dynamic alignment padding on x87 in the input frame.
+  return false;
 }
 
 
@@ -337,18 +329,6 @@ void Deoptimizer::TableEntryGenerator::Generate() {
   __ pop(eax);
   __ pop(edi);
 
-  // If frame was dynamically aligned, pop padding.
-  Label no_padding;
-  __ cmp(Operand(eax, Deoptimizer::has_alignment_padding_offset()),
-         Immediate(0));
-  __ j(equal, &no_padding);
-  __ pop(ecx);
-  if (FLAG_debug_code) {
-    __ cmp(ecx, Immediate(kAlignmentZapValue));
-    __ Assert(equal, kAlignmentMarkerExpected);
-  }
-  __ bind(&no_padding);
-
   // Replace the current frame with the output frames.
   Label outer_push_loop, inner_push_loop,
       outer_loop_header, inner_loop_header;

src/x87/frames-x87.h

@@ -28,10 +28,6 @@ const int kNumJSCallerSaved = 5;
 // Number of registers for which space is reserved in safepoints.
 const int kNumSafepointRegisters = 8;
 
-const int kNoAlignmentPadding = 0;
-const int kAlignmentPaddingPushed = 2;
-const int kAlignmentZapValue = 0x12345678;  // Not heap object tagged.
-
 // ----------------------------------------------------
 
 
@@ -75,8 +71,6 @@ class JavaScriptFrameConstants : public AllStatic {
   // Caller SP-relative.
   static const int kParam0Offset   = -2 * kPointerSize;
   static const int kReceiverOffset = -1 * kPointerSize;
-
-  static const int kDynamicAlignmentStateOffset = kLocal0Offset;
 };