Frees up LR on arm for use by the register allocator.

runtime/vm/intermediate_language_arm.cc

Index: runtime/vm/intermediate_language_arm.cc
===================================================================
--- runtime/vm/intermediate_language_arm.cc	(revision 40650)
+++ runtime/vm/intermediate_language_arm.cc	(working copy)
@@ -200,10 +200,12 @@
 LocationSummary* ClosureCallInstr::MakeLocationSummary(Isolate* isolate,
                                                        bool opt) const {
   const intptr_t kNumInputs = 1;
-  const intptr_t kNumTemps = 0;
+  const intptr_t kNumTemps = 1;
   LocationSummary* summary = new(isolate) LocationSummary(
       isolate, kNumInputs, kNumTemps, LocationSummary::kCall);
   summary->set_in(0, Location::RegisterLocation(R0));  // Function.
+  // LR is clobbered by blx.
+  summary->set_temp(0, Location::RegisterLocation(LR));

[Florian Schneider, 2014/09/25 09:49:22]

Calls clobber all registers, so I'm not sure if this is necessary.

[zra, 2014/09/25 18:11:27]

Done.

   summary->set_out(0, Location::RegisterLocation(R0));
   return summary;
 }
@@ -5093,7 +5095,7 @@
            (kind() == MathUnaryInstr::kCos));
     if (TargetCPUFeatures::hardfp_supported()) {
       __ CallRuntime(TargetFunction(), InputCount());
-      } else {
+    } else {
       // If we aren't doing "hardfp", then we have to move the double arguments
       // to the integer registers, and take the results from the integer
       // registers.