[turbofan] Add CalleeSavedFPRegisters to CallDescriptor.

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

Index: src/compiler/mips/code-generator-mips.cc
diff --git a/src/compiler/mips/code-generator-mips.cc b/src/compiler/mips/code-generator-mips.cc
index 872eeb454a58f5816af49fa4fe32a1271563e1c2..7b5d90ca3bf0bf1b091eb2eeb4e712d9c175c38e 100644
--- a/src/compiler/mips/code-generator-mips.cc
+++ b/src/compiler/mips/code-generator-mips.cc
@@ -1062,16 +1062,23 @@ void CodeGenerator::AssemblePrologue() {
   if (descriptor->kind() == CallDescriptor::kCallAddress) {
     __ Push(ra, fp);
     __ mov(fp, sp);
+
+    int register_save_area_size = 0;
     const RegList saves = descriptor->CalleeSavedRegisters();
     if (saves != 0) {  // Save callee-saved registers.
-      // TODO(plind): make callee save size const, possibly DCHECK it.
-      int register_save_area_size = 0;
-      for (int i = Register::kNumRegisters - 1; i >= 0; i--) {
-        if (!((1 << i) & saves)) continue;
-        register_save_area_size += kPointerSize;
-      }
-      frame()->SetRegisterSaveAreaSize(register_save_area_size);
       __ MultiPush(saves);
+      DCHECK(kNumCalleeSaved == base::bits::CountPopulation32(saves));

[paul.l..., 2015/06/23 02:15:02]

I really _like_ these DCHECKs to tie the new list of CalleeSavedRegisters() back
to the older implementation. So that if either is changed, that will get
noticed.

+      register_save_area_size += kNumCalleeSaved * kPointerSize;
+    }
+    const RegList saves_fpu = descriptor->CalleeSavedFPRegisters();
+    if (saves_fpu != 0) {  // Save callee-saved FPU registers.
+      __ MultiPushFPU(saves_fpu);
+      DCHECK(kNumCalleeSavedFPU == base::bits::CountPopulation32(saves_fp));
+      register_save_area_size +=
+          kNumCalleeSavedFPU * kDoubleSize * kPointerSize;
+    }
+    if (register_save_area_size > 0) {
+      frame()->SetRegisterSaveAreaSize(register_save_area_size);
     }
   } else if (descriptor->IsJSFunctionCall()) {
     CompilationInfo* info = this->info();
@@ -1115,7 +1122,12 @@ void CodeGenerator::AssembleReturn() {
       if (stack_slots > 0) {
         __ Addu(sp, sp, Operand(stack_slots * kPointerSize));
       }
-      // Restore registers.
+      // Restore FPU registers.
+      const RegList saves_fpu = descriptor->CalleeSavedFPRegisters();
+      if (saves_fpu != 0) {
+        __ MultiPopFPU(saves_fpu);
+      }
+      // Restore GP registers.
       const RegList saves = descriptor->CalleeSavedRegisters();
       if (saves != 0) {
         __ MultiPop(saves);