From b9c771c10662e4ed5645c17a606dde033fa61e6e Mon Sep 17 00:00:00 2001
From: "sgjesse@chromium.org"
 <sgjesse@chromium.org@ce2b1a6d-e550-0410-aec6-3dcde31c8c00>
Date: Thu, 12 May 2011 13:33:14 +0000
Subject: [PATCH] ARM: Reduce amount of code generated for context save on
 deopt.

BUG=none
TEST=none

Review URL: http://codereview.chromium.org//6930038

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@7873 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
---
 src/arm/deoptimizer-arm.cc | 53 +++++++++++++++++++++++++-------------
 1 file changed, 35 insertions(+), 18 deletions(-)

diff --git a/src/arm/deoptimizer-arm.cc b/src/arm/deoptimizer-arm.cc
index f0a69372f6..0298b0d178 100644
--- a/src/arm/deoptimizer-arm.cc
+++ b/src/arm/deoptimizer-arm.cc
@@ -549,13 +549,21 @@ void Deoptimizer::EntryGenerator::Generate() {
   const int kDoubleRegsSize =
       kDoubleSize * DwVfpRegister::kNumAllocatableRegisters;
 
-  // Save all general purpose registers before messing with them.
-  __ sub(sp, sp, Operand(kDoubleRegsSize));
-  for (int i = 0; i < DwVfpRegister::kNumAllocatableRegisters; ++i) {
-    DwVfpRegister vfp_reg = DwVfpRegister::FromAllocationIndex(i);
-    int offset = i * kDoubleSize;
-    __ vstr(vfp_reg, sp, offset);
+  // Save all VFP registers before messing with them.
+  DwVfpRegister first = DwVfpRegister::FromAllocationIndex(0);
+  DwVfpRegister last =
+      DwVfpRegister::FromAllocationIndex(
+          DwVfpRegister::kNumAllocatableRegisters - 1);
+  ASSERT(last.code() > first.code());
+  ASSERT((last.code() - first.code()) ==
+      (DwVfpRegister::kNumAllocatableRegisters - 1));
+#ifdef DEBUG
+  for (int i = 0; i <= (DwVfpRegister::kNumAllocatableRegisters - 1); i++) {
+    ASSERT((DwVfpRegister::FromAllocationIndex(i).code() <= last.code()) &&
+           (DwVfpRegister::FromAllocationIndex(i).code() >= first.code()));
   }
+#endif
+  __ vstm(db_w, sp, first, last);
 
   // Push all 16 registers (needed to populate FrameDescription::registers_).
   __ stm(db_w, sp, restored_regs  | sp.bit() | lr.bit() | pc.bit());
@@ -603,21 +611,30 @@ void Deoptimizer::EntryGenerator::Generate() {
 
   // Copy core registers into FrameDescription::registers_[kNumRegisters].
   ASSERT(Register::kNumRegisters == kNumberOfRegisters);
-  for (int i = 0; i < kNumberOfRegisters; i++) {
-    int offset = (i * kPointerSize) + FrameDescription::registers_offset();
-    __ ldr(r2, MemOperand(sp, i * kPointerSize));
-    __ str(r2, MemOperand(r1, offset));
-  }
+  ASSERT(kNumberOfRegisters % 2 == 0);
+
+  Label arm_loop;
+  __ add(r6, r1, Operand(FrameDescription::registers_offset()));
+  __ mov(r5, Operand(sp));
+  __ mov(r4, Operand(kNumberOfRegisters / 2));
+
+  __ bind(&arm_loop);
+  __ Ldrd(r2, r3, MemOperand(r5, kPointerSize * 2, PostIndex));
+  __ sub(r4, r4, Operand(1), SetCC);
+  __ Strd(r2, r3, MemOperand(r6, kPointerSize * 2, PostIndex));
+  __ b(gt, &arm_loop);
 
   // Copy VFP registers to
   // double_registers_[DoubleRegister::kNumAllocatableRegisters]
-  int double_regs_offset = FrameDescription::double_registers_offset();
-  for (int i = 0; i < DwVfpRegister::kNumAllocatableRegisters; ++i) {
-    int dst_offset = i * kDoubleSize + double_regs_offset;
-    int src_offset = i * kDoubleSize + kNumberOfRegisters * kPointerSize;
-    __ vldr(d0, sp, src_offset);
-    __ vstr(d0, r1, dst_offset);
-  }
+  Label vfp_loop;
+  __ add(r6, r1, Operand(FrameDescription::double_registers_offset()));
+  __ mov(r4, Operand(DwVfpRegister::kNumAllocatableRegisters));
+
+  __ bind(&vfp_loop);
+  __ Ldrd(r2, r3, MemOperand(r5, kDoubleSize, PostIndex));
+  __ sub(r4, r4, Operand(1), SetCC);
+  __ Strd(r2, r3, MemOperand(r6, kDoubleSize, PostIndex));
+  __ b(gt, &vfp_loop);
 
   // Remove the bailout id, eventually return address, and the saved registers
   // from the stack.