[turbofan] Add alignment parameter to StackSlot operator

src/compiler/instruction-selector.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/instruction-selector.h"
 
 #include <limits>
 
 #include "src/assembler-inl.h"
 #include "src/base/adapters.h"
@@ skipping 1869 matching lines @@
   inputs[1] = g.Label(sw.default_branch);
   for (size_t index = 0; index < sw.case_count; ++index) {
     int32_t value = sw.case_values[index];
     BasicBlock* branch = sw.case_branches[index];
     inputs[index * 2 + 2 + 0] = g.TempImmediate(value);
     inputs[index * 2 + 2 + 1] = g.Label(branch);
   }
   Emit(kArchLookupSwitch, 0, nullptr, input_count, inputs, 0, nullptr);
 }
 
 void InstructionSelector::VisitStackSlot(Node* node) {

[ahaas, 2017/04/24 11:43:54]

Can you move this code to platform-specific code? This CL could make the stack
frames of other platforms bigger than necessary, as far as I understand the
code.

[ivica.bogosavljevic, 2017/04/27 13:56:56]

Acknowledged.

-  int size = StackSlotSizeOf(node->op());
-  int slot = frame_->AllocateSpillSlot(size);
+  StackSlotRepresentation rep = StackSlotRepresentationOf(node->op());
+  int alignment = rep.alignment();
+  int slot = frame_->AllocateSpillSlot(rep.size(), alignment);
   OperandGenerator g(this);
 
   Emit(kArchStackSlot, g.DefineAsRegister(node),
-       sequence()->AddImmediate(Constant(slot)), 0, nullptr);
+       sequence()->AddImmediate(Constant(slot)),
+       sequence()->AddImmediate(Constant(alignment)), 0, nullptr);
 }
 
 void InstructionSelector::VisitBitcastTaggedToWord(Node* node) {
   EmitIdentity(node);
 }
 
 void InstructionSelector::VisitBitcastWordToTagged(Node* node) {
   OperandGenerator g(this);
   Emit(kArchNop, g.DefineSameAsFirst(node), g.Use(node->InputAt(0)));
 }
@@ skipping 877 matching lines @@
   return new (instruction_zone()) FrameStateDescriptor(
       instruction_zone(), state_info.type(), state_info.bailout_id(),
       state_info.state_combine(), parameters, locals, stack,
       state_info.shared_info(), outer_state);
 }
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8