[turbofan] Various fixes to allow unboxed doubles as arguments in registers and on the stack.

src/compiler/x64/code-generator-x64.cc

Index: src/compiler/x64/code-generator-x64.cc
diff --git a/src/compiler/x64/code-generator-x64.cc b/src/compiler/x64/code-generator-x64.cc
index 38c7f2a31c90724b3fd39767c07b3801fde1cbc6..a0e4299238496d109b826a1e79e73e425eb19e1f 100644
--- a/src/compiler/x64/code-generator-x64.cc
+++ b/src/compiler/x64/code-generator-x64.cc
@@ -1219,6 +1219,10 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       } else {
         if (instr->InputAt(0)->IsRegister()) {
           __ pushq(i.InputRegister(0));
+        } else if (instr->InputAt(0)->IsDoubleRegister()) {
+          // TODO(titzer): use another machine instruction?
+          __ subq(rsp, Immediate(8));

[Jarin, 2015/08/03 10:38:18]

Maybe replace 8 with kDoubleSize?

+          __ movsd(Operand(rsp, 0), i.InputDoubleRegister(0));
         } else {
           __ pushq(i.InputOperand(0));
         }
@@ -1554,31 +1558,26 @@ void CodeGenerator::AssembleReturn() {
         }
       }
       __ popq(rbp);  // Pop caller's frame pointer.
-      __ ret(0);
     } else {
       // No saved registers.
       __ movq(rsp, rbp);  // Move stack pointer back to frame pointer.
       __ popq(rbp);       // Pop caller's frame pointer.
-      __ ret(0);
     }
   } else if (descriptor->IsJSFunctionCall() || needs_frame_) {
     // Canonicalize JSFunction return sites for now.
     if (return_label_.is_bound()) {
       __ jmp(&return_label_);
+      return;
     } else {
       __ bind(&return_label_);
       __ movq(rsp, rbp);  // Move stack pointer back to frame pointer.
       __ popq(rbp);       // Pop caller's frame pointer.
-      int pop_count = static_cast<int>(descriptor->StackParameterCount());
-      if (pop_count == 0) {
-        __ Ret();
-      } else {
-        __ Ret(pop_count * kPointerSize, rbx);
-      }
     }
-  } else {
-    __ Ret();
   }
+  size_t pop_size = descriptor->StackParameterCount() * kPointerSize;
+  // Might need rcx for scratch if pop_size is too big.
+  DCHECK_EQ(0, descriptor->CalleeSavedRegisters() & rcx.bit());
+  __ Ret(static_cast<int>(pop_size), rcx);
 }