ARM: Reduce amount of code generated for context save on deopt....

src/arm/deoptimizer-arm.cc

Index: src/arm/deoptimizer-arm.cc
===================================================================
--- src/arm/deoptimizer-arm.cc	(revision 7795)
+++ src/arm/deoptimizer-arm.cc	(working copy)
@@ -550,12 +550,11 @@
       kDoubleSize * DwVfpRegister::kNumAllocatableRegisters;
 
   // Save all general purpose registers before messing with them.

[Søren Thygesen Gjesse, 2011/05/06 10:12:37]

Please also change the comment - it was already wrong before.

[m.m.capewell, 2011/05/10 10:40:25]

Done.

-  __ 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);
-  }
+  DwVfpRegister first = DwVfpRegister::FromAllocationIndex(0);

[Søren Thygesen Gjesse, 2011/05/06 10:12:37]

We should have an assert here checking that all double registers with allocation
indexes from 0 to DwVfpRegister::kNumAllocatableRegisters are between first and
last and that no "non-allocatable" registers are in the range. The mapping from
allocation index to register can be changed to any mapping.

[m.m.capewell, 2011/05/10 10:40:25]

Done.

+  DwVfpRegister last =
+      DwVfpRegister::FromAllocationIndex(
+          DwVfpRegister::kNumAllocatableRegisters - 1);
+  __ 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());
@@ -603,22 +602,31 @@
 
   // 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.
   if (type() == EAGER || type() == OSR) {