Adds support for ARM softfp calling convention.

runtime/vm/intermediate_language_arm.cc

Index: runtime/vm/intermediate_language_arm.cc
===================================================================
--- runtime/vm/intermediate_language_arm.cc	(revision 29461)
+++ runtime/vm/intermediate_language_arm.cc	(working copy)
@@ -3770,8 +3770,15 @@
         new LocationSummary(kNumInputs, kNumTemps, LocationSummary::kCall);
     summary->set_in(0, Location::FpuRegisterLocation(Q0));
     summary->set_out(Location::FpuRegisterLocation(Q0));
+#if !defined(ARM_FLOAT_ABI_HARD)
+    summary->AddTemp(Location::RegisterLocation(R0));
+    summary->AddTemp(Location::RegisterLocation(R1));
+    summary->AddTemp(Location::RegisterLocation(R2));
+    summary->AddTemp(Location::RegisterLocation(R3));
+#endif
     return summary;
   }
+  // Sqrt.
   const intptr_t kNumInputs = 1;
   const intptr_t kNumTemps = 0;
   LocationSummary* summary =
@@ -3788,7 +3795,18 @@
     DRegister result = EvenDRegisterOf(locs()->out().fpu_reg());
     __ vsqrtd(result, val);
   } else {
+#if defined(ARM_FLOAT_ABI_HARD)
     __ CallRuntime(TargetFunction(), InputCount());
+#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.
+    __ vmovrrd(R0, R1, D0);
+    __ vmovrrd(R2, R3, D1);
+    __ CallRuntime(TargetFunction(), InputCount());
+    __ vmovdrr(D0, R0, R1);
+    __ vmovdrr(D1, R2, R3);
+#endif
   }
 }
 
@@ -4079,6 +4097,15 @@
     result->AddTemp(Location::RegisterLocation(R2));
     result->AddTemp(Location::FpuRegisterLocation(Q2));
   }
+#if !defined(ARM_FLOAT_ABI_HARD)
+  result->AddTemp(Location::RegisterLocation(R0));
+  result->AddTemp(Location::RegisterLocation(R1));
+  // Check if R2 is already added.
+  if (recognized_kind() != MethodRecognizer::kMathDoublePow) {
+    result->AddTemp(Location::RegisterLocation(R2));
+  }
+  result->AddTemp(Location::RegisterLocation(R3));
+#endif
   result->set_out(Location::FpuRegisterLocation(Q0));
   return result;
 }
@@ -4121,15 +4148,22 @@
     __ vmovd(base, saved_base);  // Restore base.
   }
   __ Bind(&do_call);
-  // We currently use 'hardfp' ('gnueabihf') rather than 'softfp'
-  // ('gnueabi') float ABI for leaf runtime calls, i.e. double values
-  // are passed and returned in vfp registers rather than in integer
-  // register pairs.
   if (InputCount() == 2) {
     // Args must be in D0 and D1, so move arg from Q1(== D3:D2) to D1.
     __ vmovd(D1, D2);
   }
+#if defined(ARM_FLOAT_ABI_HARD)
   __ CallRuntime(TargetFunction(), InputCount());
+#else
+  // If the ABI is not "hardfp", then we have to move the double arguments
+  // to the integer registers, and take the results from the integer
+  // registers.
+  __ vmovrrd(R0, R1, D0);
+  __ vmovrrd(R2, R3, D1);
+  __ CallRuntime(TargetFunction(), InputCount());
+  __ vmovdrr(D0, R0, R1);
+  __ vmovdrr(D1, R2, R3);
+#endif
   __ Bind(&skip_call);
 }