[AArch64] Produce the right kind of va_arg for windows

[mstorsjo]

Summary

On windows on arm64, the va_list is a plain pointer.

[efriedma]

Needs a testcase (to check the emitted IR).

lib/CodeGen/TargetInfo.cpp

4769

Can we extend ABIKind rather than adding a separate boolean?

[mstorsjo]

lib/CodeGen/TargetInfo.cpp

4769

Sure. I was afraid there was a lot of checks like Kind == AAPCS which would need to be changed into Kind == AAPCS || Kind == Win64, but it didn't turn out to be an issue.

[mstorsjo]

Added a testcase, using a different Kind instead of adding a separate bool.

[mstorsjo]

Ping - the dependency, D35006, has now been committed.

[rnk]

lgtm

lib/CodeGen/TargetInfo.cpp

8463

Triple.isOSWindows() is probably cleaner.

lib/CodeGen/TargetInfo.cpp

 
 namespace {
 
 class AArch64ABIInfo : public SwiftABIInfo {
 public:
   enum ABIKind {
     AAPCS = 0,
     DarwinPCS
   };
 
 private:
   ABIKind Kind;
+  bool IsMS;
 
 public:
-  AArch64ABIInfo(CodeGenTypes &CGT, ABIKind Kind)
-    : SwiftABIInfo(CGT), Kind(Kind) {}
+  AArch64ABIInfo(CodeGenTypes &CGT, ABIKind Kind, bool MS)
+      : SwiftABIInfo(CGT), Kind(Kind), IsMS(MS) {}
 
 private:
   ABIKind getABIKind() const { return Kind; }
   bool isDarwinPCS() const { return Kind == DarwinPCS; }
 
   ABIArgInfo classifyReturnType(QualType RetTy) const;
   ABIArgInfo classifyArgumentType(QualType RetTy) const;
   bool isHomogeneousAggregateBaseType(QualType Ty) const override;
private:
   Address EmitDarwinVAArg(Address VAListAddr, QualType Ty,
                           CodeGenFunction &CGF) const;
 
   Address EmitAAPCSVAArg(Address VAListAddr, QualType Ty,
                          CodeGenFunction &CGF) const;
 
   Address EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
                     QualType Ty) const override {
-    return isDarwinPCS() ? EmitDarwinVAArg(VAListAddr, Ty, CGF)
+    return IsMS ? EmitMSVAArg(CGF, VAListAddr, Ty)
+                : isDarwinPCS() ? EmitDarwinVAArg(VAListAddr, Ty, CGF)
                                 : EmitAAPCSVAArg(VAListAddr, Ty, CGF);
   }
+  Address EmitMSVAArg(CodeGenFunction &CGF, Address VAListAddr,
+                      QualType Ty) const override;
 
   bool shouldPassIndirectlyForSwift(CharUnits totalSize,
                                     ArrayRef<llvm::Type*> scalars,
                                     bool asReturnValue) const override {
     return occupiesMoreThan(CGT, scalars, /*total*/ 4);
   }
   bool isSwiftErrorInRegister() const override {
     return true;
   }
 
   bool isLegalVectorTypeForSwift(CharUnits totalSize, llvm::Type *eltTy,
                                  unsigned elts) const override;
 };
 
 class AArch64TargetCodeGenInfo : public TargetCodeGenInfo {
 public:
-  AArch64TargetCodeGenInfo(CodeGenTypes &CGT, AArch64ABIInfo::ABIKind Kind)
-      : TargetCodeGenInfo(new AArch64ABIInfo(CGT, Kind)) {}
+  AArch64TargetCodeGenInfo(CodeGenTypes &CGT, AArch64ABIInfo::ABIKind Kind,
+                           bool IsMS)
+      : TargetCodeGenInfo(new AArch64ABIInfo(CGT, Kind, IsMS)) {}
 
   StringRef getARCRetainAutoreleasedReturnValueMarker() const override {
     return "mov\tfp, fp\t\t# marker for objc_retainAutoreleaseReturnValue";
   }
 
   int getDwarfEHStackPointer(CodeGen::CodeGenModule &M) const override {
     return 31;
   }
if (TyInfo.first.getQuantity() > 16) {
     uint64_t Members = 0;
     IsIndirect = !isHomogeneousAggregate(Ty, Base, Members);
   }
 
   return emitVoidPtrVAArg(CGF, VAListAddr, Ty, IsIndirect,
                           TyInfo, SlotSize, /*AllowHigherAlign*/ true);
 }
 
+Address AArch64ABIInfo::EmitMSVAArg(CodeGenFunction &CGF, Address VAListAddr,
+                                    QualType Ty) const {
+  return emitVoidPtrVAArg(CGF, VAListAddr, Ty, /*indirect*/ false,
+                          CGF.getContext().getTypeInfoInChars(Ty),
+                          CharUnits::fromQuantity(8),
+                          /*allowHigherAlign*/ false);
+}
+
 //===----------------------------------------------------------------------===//
 // ARM ABI Implementation
 //===----------------------------------------------------------------------===//
 
 namespace {
 
 class ARMABIInfo : public SwiftABIInfo {
 public:
const TargetCodeGenInfo &CodeGenModule::getTargetCodeGenInfo() {
   case llvm::Triple::avr:
     return SetCGInfo(new AVRTargetCodeGenInfo(Types));
 
   case llvm::Triple::aarch64:
   case llvm::Triple::aarch64_be: {
     AArch64ABIInfo::ABIKind Kind = AArch64ABIInfo::AAPCS;
     if (getTarget().getABI() == "darwinpcs")
       Kind = AArch64ABIInfo::DarwinPCS;
 
-    return SetCGInfo(new AArch64TargetCodeGenInfo(Types, Kind));
+    return SetCGInfo(new AArch64TargetCodeGenInfo(
+        Types, Kind, Triple.getOS() == llvm::Triple::Win32));
   }
 
   case llvm::Triple::wasm32:
   case llvm::Triple::wasm64:
     return SetCGInfo(new WebAssemblyTargetCodeGenInfo(Types));
 
   case llvm::Triple::arm:
   case llvm::Triple::armeb: