[turbofan] Factor C call descriptor building into compiler/c-linkage.cc.

src/compiler/x64/linkage-x64.cc

Index: src/compiler/x64/linkage-x64.cc
diff --git a/src/compiler/x64/linkage-x64.cc b/src/compiler/x64/linkage-x64.cc
index a49e6b3e35dc53d1b4d5f77212ab3eddf50f5304..559d8aab039f13ceb6da84178b290d5334469a31 100644
--- a/src/compiler/x64/linkage-x64.cc
+++ b/src/compiler/x64/linkage-x64.cc
@@ -12,12 +12,6 @@ namespace v8 {
 namespace internal {
 namespace compiler {
 
-#ifdef _WIN64
-const bool kWin64 = true;
-#else
-const bool kWin64 = false;
-#endif
-
 struct X64LinkageHelperTraits {
   static Register ReturnValueReg() { return rax; }
   static Register ReturnValue2Reg() { return rdx; }
@@ -27,35 +21,6 @@ struct X64LinkageHelperTraits {
   static Register InterpreterDispatchTableReg() { return rdi; }
   static Register RuntimeCallFunctionReg() { return rbx; }
   static Register RuntimeCallArgCountReg() { return rax; }
-  static RegList CCalleeSaveRegisters() {
-    if (kWin64) {
-      return rbx.bit() | rdi.bit() | rsi.bit() | r12.bit() | r13.bit() |
-             r14.bit() | r15.bit();
-    } else {
-      return rbx.bit() | r12.bit() | r13.bit() | r14.bit() | r15.bit();
-    }
-  }
-  static RegList CCalleeSaveFPRegisters() {
-    if (kWin64) {
-      return (1 << xmm6.code()) | (1 << xmm7.code()) | (1 << xmm8.code()) |
-             (1 << xmm9.code()) | (1 << xmm10.code()) | (1 << xmm11.code()) |
-             (1 << xmm12.code()) | (1 << xmm13.code()) | (1 << xmm14.code()) |
-             (1 << xmm15.code());
-    } else {
-      return 0;
-    }
-  }
-  static Register CRegisterParameter(int i) {
-    if (kWin64) {
-      static Register register_parameters[] = {rcx, rdx, r8, r9};
-      return register_parameters[i];
-    } else {
-      static Register register_parameters[] = {rdi, rsi, rdx, rcx, r8, r9};
-      return register_parameters[i];
-    }
-  }
-  static int CRegisterParametersLength() { return kWin64 ? 4 : 6; }
-  static int CStackBackingStoreLength() { return kWin64 ? 4 : 0; }
 };
 
 typedef LinkageHelper<X64LinkageHelperTraits> LH;
@@ -85,12 +50,6 @@ CallDescriptor* Linkage::GetStubCallDescriptor(
 }
 
 
-CallDescriptor* Linkage::GetSimplifiedCDescriptor(Zone* zone,
-                                                  const MachineSignature* sig) {
-  return LH::GetSimplifiedCDescriptor(zone, sig);
-}
-
-
 CallDescriptor* Linkage::GetInterpreterDispatchDescriptor(Zone* zone) {
   return LH::GetInterpreterDispatchDescriptor(zone);
 }