[v8-dev] ARM: safepoints frame optimization

src/arm/lithium-codegen-arm.cc

Index: src/arm/lithium-codegen-arm.cc
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index b10ed59b1b1c9ad80ea55cbff45f013a34af9a8d..6c43ceb4d7e7a7f71f135e59aa66c75484c4cede 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -67,6 +67,38 @@ bool LCodeGen::GenerateCode() {
   ASSERT(is_unused());
   status_ = GENERATING;
 
+  chunk()->add_safepoints_registers(r10.bit() | fp.bit());
+  // Add some double registers to save to be able to save all registers with
+  // only two vstm instructions.
+  int first = -1;
+  int last = -1;
+  for (int i = 0; i < LowDwVfpRegister::kMaxNumLowRegisters; i++) {
+    if ((chunk()->safepoints_double_registers() & (1 << i)) != 0) {
+      if (first == -1) first = i;
+      last = i;
+    }
+  }
+  if (first != -1) {
+    chunk()->add_safepoints_double_registers(
+        ((1 << last) - 1) & ~((1 << first) - 1));
+  }
+  first = -1;
+  last = -1;
+  for (int i = LowDwVfpRegister::kMaxNumLowRegisters;
+       i < DoubleRegister::NumRegisters();
+       i++) {
+    if ((chunk()->safepoints_double_registers() & (1 << i)) != 0) {
+      if (first == -1) first = i;
+      last = i;
+    }
+  }
+  if (first != -1) {
+    chunk()->add_safepoints_double_registers(
+        ((1 << last) - 1) & ~((1 << first) - 1));
+  }
+  masm_->set_registers_masks(chunk()->safepoints_registers(),
+                             chunk()->safepoints_double_registers());
+
   // Open a frame scope to indicate that there is a frame on the stack.  The
   // NONE indicates that the scope shouldn't actually generate code to set up
   // the frame (that is done in GeneratePrologue).
@@ -5077,7 +5109,8 @@ void LCodeGen::DoDeferredInstanceMigration(LCheckMaps* instr, Register object) {
     __ CallRuntimeSaveDoubles(Runtime::kTryMigrateInstance);
     RecordSafepointWithRegisters(
         instr->pointer_map(), 1, Safepoint::kNoLazyDeopt);
-    __ StoreToSafepointRegisterSlot(r0, scratch0());
+    ASSERT((chunk()->safepoints_registers() & scratch0().bit()) == 0);
+    __ mov(scratch0(), r0);
   }
   __ tst(scratch0(), Operand(kSmiTagMask));
   DeoptimizeIf(eq, instr->environment());