[PATCH] [mips] Defer va_arg expansion to the backend.

[Daniel Sanders]

Sorry, this should have been sent to cfe-commits. I've corrected this.

> -----Original Message-----
> From: Daniel Sanders
> Sent: 31 July 2014 17:31
> To: Daniel Sanders; Sasa Stankovic
> Cc: llvm-commits at cs.uiuc.edu
> Subject: Re: [PATCH] [mips] Defer va_arg expansion to the backend.
> 
> Remove swap files that were accidentally added in the 'arc diff' command.
> 
> http://reviews.llvm.org/D4742
> 
> Files:
>   lib/CodeGen/TargetInfo.cpp
>   test/CodeGen/mips-vaarg.c
> 
> Index: lib/CodeGen/TargetInfo.cpp
> ==========================================================
> =========
> --- lib/CodeGen/TargetInfo.cpp
> +++ lib/CodeGen/TargetInfo.cpp
> @@ -5560,39 +5560,7 @@
> 
>  llvm::Value* MipsABIInfo::EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
>                                      CodeGenFunction &CGF) const {
> -  llvm::Type *BP = CGF.Int8PtrTy;
> -  llvm::Type *BPP = CGF.Int8PtrPtrTy;
> -
> -  CGBuilderTy &Builder = CGF.Builder;
> -  llvm::Value *VAListAddrAsBPP = Builder.CreateBitCast(VAListAddr, BPP,
> "ap");
> -  llvm::Value *Addr = Builder.CreateLoad(VAListAddrAsBPP, "ap.cur");
> -  int64_t TypeAlign = getContext().getTypeAlign(Ty) / 8;
> -  llvm::Type *PTy = llvm::PointerType::getUnqual(CGF.ConvertType(Ty));
> -  llvm::Value *AddrTyped;
> -  unsigned PtrWidth = getTarget().getPointerWidth(0);
> -  llvm::IntegerType *IntTy = (PtrWidth == 32) ? CGF.Int32Ty : CGF.Int64Ty;
> -
> -  if (TypeAlign > MinABIStackAlignInBytes) {
> -    llvm::Value *AddrAsInt = CGF.Builder.CreatePtrToInt(Addr, IntTy);
> -    llvm::Value *Inc = llvm::ConstantInt::get(IntTy, TypeAlign - 1);
> -    llvm::Value *Mask = llvm::ConstantInt::get(IntTy, -TypeAlign);
> -    llvm::Value *Add = CGF.Builder.CreateAdd(AddrAsInt, Inc);
> -    llvm::Value *And = CGF.Builder.CreateAnd(Add, Mask);
> -    AddrTyped = CGF.Builder.CreateIntToPtr(And, PTy);
> -  }
> -  else
> -    AddrTyped = Builder.CreateBitCast(Addr, PTy);
> -
> -  llvm::Value *AlignedAddr = Builder.CreateBitCast(AddrTyped, BP);
> -  TypeAlign = std::max((unsigned)TypeAlign, MinABIStackAlignInBytes);
> -  uint64_t Offset =
> -    llvm::RoundUpToAlignment(CGF.getContext().getTypeSize(Ty) / 8,
> TypeAlign);
> -  llvm::Value *NextAddr =
> -    Builder.CreateGEP(AlignedAddr, llvm::ConstantInt::get(IntTy, Offset),
> -                      "ap.next");
> -  Builder.CreateStore(NextAddr, VAListAddrAsBPP);
> -
> -  return AddrTyped;
> +  return nullptr;
>  }
> 
>  bool
> Index: test/CodeGen/mips-vaarg.c
> ==========================================================
> =========
> --- /dev/null
> +++ test/CodeGen/mips-vaarg.c
> @@ -0,0 +1,18 @@
> +// RUN: %clang -target mips-unknown-linux -S -o - -emit-llvm %s | FileCheck
> %s
> +// RUN: %clang -target mipsel-unknown-linux -S -o - -emit-llvm %s |
> FileCheck %s
> +// RUN: %clang -target mips64-unknown-linux -S -o - -emit-llvm %s |
> FileCheck %s
> +// RUN: %clang -target mips64el-unknown-linux -S -o - -emit-llvm %s |
> FileCheck %s
> +
> +int foo (int a, ...)
> +{
> +    __builtin_va_list va;
> +
> +    __builtin_va_start (va, a);
> +
> +    int n = __builtin_va_arg (va, int);
> +    // CHECK: = va_arg i8** %va, i32
> +
> +    __builtin_va_end (va);
> +
> +    return n;
> +}