[turbofan] Fewer gap moves for tail calls

src/compiler/arm/code-generator-arm.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/arm/macro-assembler-arm.h"
 #include "src/ast/scopes.h"
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
@@ skipping 341 matching lines @@
     __ asm_instr(value, i.InputOffset(3), lo);    \
     DCHECK_EQ(LeaveCC, i.OutputSBit());           \
   } while (0)
 
 
 void CodeGenerator::AssembleDeconstructActivationRecord(int stack_param_delta) {
   int sp_slot_delta = TailCallFrameStackSlotDelta(stack_param_delta);
   if (sp_slot_delta > 0) {
     __ add(sp, sp, Operand(sp_slot_delta * kPointerSize));
   }
-  if (frame()->needs_frame()) {
-    if (FLAG_enable_embedded_constant_pool) {
-      __ ldm(ia_w, sp, pp.bit() | fp.bit() | lr.bit());
-    } else {
-      __ ldm(ia_w, sp, fp.bit() | lr.bit());
-    }
-  }
   frame_access_state()->SetFrameAccessToDefault();
 }
 
 
 void CodeGenerator::AssemblePrepareTailCall(int stack_param_delta) {
   int sp_slot_delta = TailCallFrameStackSlotDelta(stack_param_delta);
   if (sp_slot_delta < 0) {
     __ sub(sp, sp, Operand(-sp_slot_delta * kPointerSize));
     frame_access_state()->IncreaseSPDelta(-sp_slot_delta);
   }
+  if (frame()->needs_frame()) {
+    if (FLAG_enable_embedded_constant_pool) {
+      __ ldr(cp, MemOperand(fp, StandardFrameConstants::kConstantPoolOffset));
+    }
+    __ ldr(lr, MemOperand(fp, StandardFrameConstants::kCallerPCOffset));
+    __ ldr(fp, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
+  }
   frame_access_state()->SetFrameAccessToSP();
 }
 
 
 // Assembles an instruction after register allocation, producing machine code.
 void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
   ArmOperandConverter i(this, instr);
 
   masm()->MaybeCheckConstPool();
 
@@ skipping 986 matching lines @@
       padding_size -= v8::internal::Assembler::kInstrSize;
     }
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8