Target/X86: Add explicit Win64 and System V/x86-64 calling conventions.

Summary:
This patch adds explicit calling convention types for the Win64 and
System V/x86-64 ABIs. This allows code to override the default, and use
the Win64 convention on a target that wants to use SysV (and
vice-versa). This is needed to implement the `ms_abi` and `sysv_abi` GNU
attributes.

Reviewers:

CC:

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186144 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 1 deletions

diff --git a/lib/Target/X86/X86Subtarget.h b/lib/Target/X86/X86Subtarget.h
index 66832b9..01a28d0 100644
--- a/lib/Target/X86/X86Subtarget.h
+++ b/lib/Target/X86/X86Subtarget.h
@@ -338,7 +338,13 @@ public:
   }
   bool isPICStyleStubAny() const {
     return PICStyle == PICStyles::StubDynamicNoPIC ||
-           PICStyle == PICStyles::StubPIC; }
+           PICStyle == PICStyles::StubPIC;
+  }
+
+  bool isCallingConvWin64(CallingConv::ID CC) const {
+    return (isTargetWin64() && CC != CallingConv::X86_64_SysV) ||
+           CC == CallingConv::X86_64_Win64;
+  }
 
   /// ClassifyGlobalReference - Classify a global variable reference for the
   /// current subtarget according to how we should reference it in a non-pcrel