Target/X86: Save Win64 non-volatile registers in a Win64 ABI function.

[cdavis5x]

Summary

This change causes us to actually save non-volatile registers in a Win64
ABI function that calls a System V ABI function, and vice-versa.

[rnk]

lgtm

test/CodeGen/X86/win64_nonvol.ll

7–11 ↗

(On Diff #20798)

This can be simplified to a declaration.

llvm/trunk/lib/Target/X86/X86RegisterInfo.cpp

case X86::VR64RegClassID:
     return 4;
   }
 }
 
 const MCPhysReg *
 X86RegisterInfo::getCalleeSavedRegs(const MachineFunction *MF) const {
   bool HasAVX = Subtarget.hasAVX();
   bool HasAVX512 = Subtarget.hasAVX512();
+  bool CallsEHReturn = MF->getMMI().callsEHReturn();
 
   assert(MF && "MachineFunction required");
   switch (MF->getFunction()->getCallingConv()) {
   case CallingConv::GHC:
   case CallingConv::HiPE:
     return CSR_NoRegs_SaveList;
   case CallingConv::AnyReg:
     if (HasAVX)
case CallingConv::Intel_OCL_BI: {
     if (!HasAVX && !IsWin64 && Is64Bit)
       return CSR_64_Intel_OCL_BI_SaveList;
     break;
   }
   case CallingConv::Cold:
     if (Is64Bit)
       return CSR_64_MostRegs_SaveList;
     break;
+  case CallingConv::X86_64_Win64:
+    return CSR_Win64_SaveList;
+  case CallingConv::X86_64_SysV:
+    if (CallsEHReturn)
+      return CSR_64EHRet_SaveList;
+    return CSR_64_SaveList;
   default:
     break;
   }
 
-  bool CallsEHReturn = MF->getMMI().callsEHReturn();
   if (Is64Bit) {
     if (IsWin64)
       return CSR_Win64_SaveList;
     if (CallsEHReturn)
       return CSR_64EHRet_SaveList;
     return CSR_64_SaveList;
   }
   if (CallsEHReturn)
case CallingConv::Intel_OCL_BI: {
     break;
   }
   case CallingConv::Cold:
     if (Is64Bit)
       return CSR_64_MostRegs_RegMask;
     break;
   default:
     break;
+  case CallingConv::X86_64_Win64:
+    return CSR_Win64_RegMask;
+  case CallingConv::X86_64_SysV:
+    return CSR_64_RegMask;
   }
 
   // Unlike getCalleeSavedRegs(), we don't have MMI so we can't check
   // callsEHReturn().
   if (Is64Bit) {
     if (IsWin64)
       return CSR_Win64_RegMask;
     return CSR_64_RegMask;

llvm/trunk/test/CodeGen/X86/win64_nonvol.ll

+; RUN: llc < %s -mtriple=x86_64-pc-win32 | FileCheck %s
+; RUN: llc < %s -mtriple=x86_64-pc-linux | FileCheck %s
+
+; Check that, if a Win64 ABI function calls a SysV ABI function, all the
+; Win64 nonvolatile registers get saved.
+
+; CHECK-LABEL: bar:
+define x86_64_win64cc void @bar(i32 %a, i32 %b) {
+; CHECK-DAG: pushq %rdi
+; CHECK-DAG: pushq %rsi
+; CHECK-DAG: movaps %xmm6,
+; CHECK-DAG: movaps %xmm7,
+; CHECK-DAG: movaps %xmm8,
+; CHECK-DAG: movaps %xmm9,
+; CHECK-DAG: movaps %xmm10,
+; CHECK-DAG: movaps %xmm11,
+; CHECK-DAG: movaps %xmm12,
+; CHECK-DAG: movaps %xmm13,
+; CHECK-DAG: movaps %xmm14,
+; CHECK-DAG: movaps %xmm15,
+; CHECK: callq foo
+; CHECK: ret
+  call x86_64_sysvcc void @foo(i32 %a, i32 %b)
+  ret void
+}
+
+declare x86_64_sysvcc void @foo(i32 %a, i32 %b)
+