Clean up JNI calling convention callee saves.

Precalculate callee saves at compile time and return them
as ArrayRef<> instead of keeping then in a std::vector<>.

Change-Id: I4fd7d2bbf6138dc31b0fe8554eac35b0777ec9ef
diff --git a/compiler/jni/quick/x86/calling_convention_x86.cc b/compiler/jni/quick/x86/calling_convention_x86.cc
index 322caca..22c7cd0 100644
--- a/compiler/jni/quick/x86/calling_convention_x86.cc
+++ b/compiler/jni/quick/x86/calling_convention_x86.cc
@@ -23,6 +23,28 @@
 namespace art {
 namespace x86 {
 
+static constexpr ManagedRegister kCalleeSaveRegisters[] = {
+    // Core registers.
+    X86ManagedRegister::FromCpuRegister(EBP),
+    X86ManagedRegister::FromCpuRegister(ESI),
+    X86ManagedRegister::FromCpuRegister(EDI),
+    // No hard float callee saves.
+};
+
+static constexpr uint32_t CalculateCoreCalleeSpillMask() {
+  // The spilled PC gets a special marker.
+  uint32_t result = 1 << kNumberOfCpuRegisters;
+  for (auto&& r : kCalleeSaveRegisters) {
+    if (r.AsX86().IsCpuRegister()) {
+      result |= (1 << r.AsX86().AsCpuRegister());
+    }
+  }
+  return result;
+}
+
+static constexpr uint32_t kCoreCalleeSpillMask = CalculateCoreCalleeSpillMask();
+static constexpr uint32_t kFpCalleeSpillMask = 0u;
+
 // Calling convention
 
 ManagedRegister X86ManagedRuntimeCallingConvention::InterproceduralScratchRegister() {
@@ -169,13 +191,14 @@
 X86JniCallingConvention::X86JniCallingConvention(bool is_static, bool is_synchronized,
                                                  const char* shorty)
     : JniCallingConvention(is_static, is_synchronized, shorty, kFramePointerSize) {
-  callee_save_regs_.push_back(X86ManagedRegister::FromCpuRegister(EBP));
-  callee_save_regs_.push_back(X86ManagedRegister::FromCpuRegister(ESI));
-  callee_save_regs_.push_back(X86ManagedRegister::FromCpuRegister(EDI));
 }
 
 uint32_t X86JniCallingConvention::CoreSpillMask() const {
-  return 1 << EBP | 1 << ESI | 1 << EDI | 1 << kNumberOfCpuRegisters;
+  return kCoreCalleeSpillMask;
+}
+
+uint32_t X86JniCallingConvention::FpSpillMask() const {
+  return kFpCalleeSpillMask;
 }
 
 size_t X86JniCallingConvention::FrameSize() {
@@ -192,6 +215,10 @@
   return RoundUp(NumberOfOutgoingStackArgs() * kFramePointerSize, kStackAlignment);
 }
 
+ArrayRef<const ManagedRegister> X86JniCallingConvention::CalleeSaveRegisters() const {
+  return ArrayRef<const ManagedRegister>(kCalleeSaveRegisters);
+}
+
 bool X86JniCallingConvention::IsCurrentParamInRegister() {
   return false;  // Everything is passed by stack.
 }