Add support for thiscall calling convention.

Patch by Charles Davis and Steven Watanabe!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103902 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 30 insertions, 2 deletions

diff --git a/lib/Target/CBackend/CBackend.cpp b/lib/Target/CBackend/CBackend.cpp
index cc9e1d7..55b8aaa 100644
--- a/lib/Target/CBackend/CBackend.cpp
+++ b/lib/Target/CBackend/CBackend.cpp
@@ -2165,6 +2165,9 @@ void CWriter::printFunctionSignature(const Function *F, bool Prototype) {
    case CallingConv::X86_FastCall:
     Out << "__attribute__((fastcall)) ";
     break;
+   case CallingConv::X86_ThisCall:
+    Out << "__attribute__((thiscall)) ";
+    break;
    default:
     break;
   }
diff --git a/lib/Target/MSIL/MSILWriter.cpp b/lib/Target/MSIL/MSILWriter.cpp
index 332a150..3de173c 100644
--- a/lib/Target/MSIL/MSILWriter.cpp
+++ b/lib/Target/MSIL/MSILWriter.cpp
@@ -278,6 +278,8 @@ std::string MSILWriter::getConvModopt(CallingConv::ID CallingConvID) {
     return "modopt([mscorlib]System.Runtime.CompilerServices.CallConvFastcall) ";
   case CallingConv::X86_StdCall:
     return "modopt([mscorlib]System.Runtime.CompilerServices.CallConvStdcall) ";
+  case CallingConv::X86_ThisCall:
+    return "modopt([mscorlib]System.Runtime.CompilerServices.CallConvThiscall) ";
   default:
     errs() << "CallingConvID = " << CallingConvID << '\n';
     llvm_unreachable("Unsupported calling convention");
diff --git a/lib/Target/X86/X86CallingConv.td b/lib/Target/X86/X86CallingConv.td
index fd15efd..a5774e1 100644
--- a/lib/Target/X86/X86CallingConv.td
+++ b/lib/Target/X86/X86CallingConv.td
@@ -307,6 +307,20 @@ def CC_X86_32_FastCall : CallingConv<[
   CCDelegateTo<CC_X86_32_Common>
 ]>;
 
+def CC_X86_32_ThisCall : CallingConv<[
+  // Promote i8/i16 arguments to i32.
+  CCIfType<[i8, i16], CCPromoteToType<i32>>,
+
+  // The 'nest' parameter, if any, is passed in EAX.
+  CCIfNest<CCAssignToReg<[EAX]>>,
+
+  // The first integer argument is passed in ECX
+  CCIfType<[i32], CCAssignToReg<[ECX]>>,
+
+  // Otherwise, same as everything else.
+  CCDelegateTo<CC_X86_32_Common>
+]>;
+
 def CC_X86_32_FastCC : CallingConv<[
   // Handles byval parameters.  Note that we can't rely on the delegation
   // to CC_X86_32_Common for this because that happens after code that
diff --git a/lib/Target/X86/X86FastISel.cpp b/lib/Target/X86/X86FastISel.cpp
index 953ba18..7f97b48 100644
--- a/lib/Target/X86/X86FastISel.cpp
+++ b/lib/Target/X86/X86FastISel.cpp
@@ -180,6 +180,8 @@ CCAssignFn *X86FastISel::CCAssignFnForCall(CallingConv::ID CC,
 
   if (CC == CallingConv::X86_FastCall)
     return CC_X86_32_FastCall;
+  else if (CC == CallingConv::X86_ThisCall)
+    return CC_X86_32_ThisCall;
   else if (CC == CallingConv::Fast)
     return CC_X86_32_FastCC;
   else if (CC == CallingConv::GHC)
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 88ee52f..9fa7bb1 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -1383,6 +1383,8 @@ bool X86TargetLowering::IsCalleePop(bool IsVarArg,
     return !Subtarget->is64Bit();
   case CallingConv::X86_FastCall:
     return !Subtarget->is64Bit();
+  case CallingConv::X86_ThisCall:
+    return !Subtarget->is64Bit();
   case CallingConv::Fast:
     return GuaranteedTailCallOpt;
   case CallingConv::GHC:
@@ -1404,6 +1406,8 @@ CCAssignFn *X86TargetLowering::CCAssignFnForNode(CallingConv::ID CC) const {
 
   if (CC == CallingConv::X86_FastCall)
     return CC_X86_32_FastCall;
+  else if (CC == CallingConv::X86_ThisCall)
+    return CC_X86_32_ThisCall;
   else if (CC == CallingConv::Fast)
     return CC_X86_32_FastCC;
   else if (CC == CallingConv::GHC)
@@ -1595,7 +1599,8 @@ X86TargetLowering::LowerFormalArguments(SDValue Chain,
   // If the function takes variable number of arguments, make a frame index for
   // the start of the first vararg value... for expansion of llvm.va_start.
   if (isVarArg) {
-    if (Is64Bit || CallConv != CallingConv::X86_FastCall) {
+    if (Is64Bit || (CallConv != CallingConv::X86_FastCall &&
+                    CallConv != CallingConv::X86_ThisCall)) {
       FuncInfo->setVarArgsFrameIndex(MFI->CreateFixedObject(1, StackSize,
                                                             true, false));
     }
@@ -1715,7 +1720,8 @@ X86TargetLowering::LowerFormalArguments(SDValue Chain,
   if (!Is64Bit) {
     // RegSaveFrameIndex is X86-64 only.
     FuncInfo->setRegSaveFrameIndex(0xAAAAAAA);
-    if (CallConv == CallingConv::X86_FastCall)
+    if (CallConv == CallingConv::X86_FastCall ||
+        CallConv == CallingConv::X86_ThisCall)
       // fastcc functions can't have varargs.
       FuncInfo->setVarArgsFrameIndex(0xAAAAAAA);
   }
@@ -7119,6 +7125,7 @@ SDValue X86TargetLowering::LowerTRAMPOLINE(SDValue Op,
       break;
     }
     case CallingConv::X86_FastCall:
+    case CallingConv::X86_ThisCall:
     case CallingConv::Fast:
       // Pass 'nest' parameter in EAX.
       // Must be kept in sync with X86CallingConv.td