Generate StoreGlobal stubs with Hydrogen

src/ia32/lithium-gap-resolver-ia32.cc

Index: src/ia32/lithium-gap-resolver-ia32.cc
diff --git a/src/ia32/lithium-gap-resolver-ia32.cc b/src/ia32/lithium-gap-resolver-ia32.cc
index 3da8f320d0b897e4fe66efe6fed9f8d45839384c..cd8442112543099ef2a6c7d1b27d784612005ff7 100644
--- a/src/ia32/lithium-gap-resolver-ia32.cc
+++ b/src/ia32/lithium-gap-resolver-ia32.cc
@@ -313,6 +313,31 @@ void LGapResolver::EmitMove(int index) {
       } else {
         __ LoadObject(dst, cgen_->ToHandle(constant_source));
       }
+    } else if (destination->IsDoubleRegister()) {
+      double v = cgen_->ToDouble(constant_source);
+      uint64_t int_val = BitCast<uint64_t, double>(v);
+      int32_t lower = static_cast<int32_t>(int_val);
+      int32_t upper = static_cast<int32_t>(int_val >> (kBitsPerInt));

[rossberg, 2013/06/25 10:47:38]

Nit: redundant parens

[danno, 2013/06/28 13:56:05]

Done.

+      if (CpuFeatures::IsSupported(SSE2)) {
+        CpuFeatureScope scope(cgen_->masm(), SSE2);
+        XMMRegister dst = cgen_->ToDoubleRegister(destination);
+        if (int_val == 0) {
+          __ xorps(dst, dst);
+        } else {
+          __ push(Immediate(upper));
+          __ push(Immediate(lower));
+          __ movdbl(dst, Operand(esp, 0));
+          __ add(esp, Immediate(kDoubleSize));
+        }
+      } else {
+        __ push(Immediate(upper));
+        __ push(Immediate(lower));
+        if (cgen_->X87StackNonEmpty()) {
+          cgen_->PopX87();

[rossberg, 2013/06/25 10:47:38]

Hm, why this?

[danno, 2013/06/28 13:56:05]

This is an artifact of how we use the x87 FP stack on non-SSE machines. The
invariant is that there can only be a single value on the FP stack at once. If
there is a value on the stack, it is no longer live, but the register allocation
doesn't do anything special for live ranges that end, so we much handle that
explicitly by popping a value of the FP stack when the next live value begins. 

This is kind of an idiom used here and elsewhere in Crankshaft non-SSE2 FP code.

+        }
+        cgen_->PushX87DoubleOperand(MemOperand(esp, 0));
+        __ add(esp, Immediate(kDoubleSize));
+      }
     } else {
       ASSERT(destination->IsStackSlot());
       Operand dst = cgen_->ToOperand(destination);