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

src/arm/deoptimizer-arm.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 531 matching lines @@
   CpuFeatures::Scope scope(VFP3);
   // Save all general purpose registers before messing with them.
   const int kNumberOfRegisters = Register::kNumRegisters;
 
   // Everything but pc, lr and ip which will be saved but not restored.
   RegList restored_regs = kJSCallerSaved | kCalleeSaved | ip.bit();
 
   const int kDoubleRegsSize =
       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());
 
   const int kSavedRegistersAreaSize =
       (kNumberOfRegisters * kPointerSize) + kDoubleRegsSize;
 
   // Get the bailout id from the stack.
   __ ldr(r2, MemOperand(sp, kSavedRegistersAreaSize));
 
@@ skipping 27 matching lines @@
   __ str(r5, MemOperand(sp, 1 * kPointerSize));  // Isolate.
   // Call Deoptimizer::New().
   __ CallCFunction(ExternalReference::new_deoptimizer_function(isolate), 6);
 
   // Preserve "deoptimizer" object in register r0 and get the input
   // frame descriptor pointer to r1 (deoptimizer->input_);
   __ ldr(r1, MemOperand(r0, Deoptimizer::input_offset()));
 
   // 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) {
     __ add(sp, sp, Operand(kSavedRegistersAreaSize + (1 * kPointerSize)));
   } else {
     __ add(sp, sp, Operand(kSavedRegistersAreaSize + (2 * kPointerSize)));
   }
 
   // Compute a pointer to the unwinding limit in register r2; that is
@@ skipping 97 matching lines @@
     __ push(ip);
     __ b(&done);
     ASSERT(masm()->pc_offset() - start == table_entry_size_);
   }
   __ bind(&done);
 }
 
 #undef __
 
 } }  // namespace v8::internal