Revert r214497: [mips] Defer va_arg expansion to the backend.

It appears that the backend does not handle all cases that were handled by clang.
In particular, it does not handle structs as used in
SingleSource/UnitTests/2003-05-07-VarArgs.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@214512 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/TargetInfo.cpp b/lib/CodeGen/TargetInfo.cpp
index 3870f72487d9ff811748e58242057d1bc5af2e02..ca99ba580a57ff5766964d039874d4f2c460a0f0 100644 (file)
--- a/lib/CodeGen/TargetInfo.cpp
+++ b/lib/CodeGen/TargetInfo.cpp
@@ -5560,7 +5560,39 @@ void MipsABIInfo::computeInfo(CGFunctionInfo &FI) const {
 
 llvm::Value* MipsABIInfo::EmitVAArg(llvm::Value *VAListAddr, QualType Ty,
                                     CodeGenFunction &CGF) const {
-  return nullptr;
+  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;
 }
 
 bool

diff --git a/test/CodeGen/mips-vaarg.c b/test/CodeGen/mips-vaarg.c
deleted file mode 100644 (file)
index f685ed8..0000000
--- a/test/CodeGen/mips-vaarg.c
+++ /dev/null
@@ -1,29 +0,0 @@
-// RUN: %clang -target mips-unknown-linux     -S -o - -emit-llvm %s | FileCheck --check-prefix=ALL --check-prefix=O32 %s
-// RUN: %clang -target mipsel-unknown-linux   -S -o - -emit-llvm %s | FileCheck --check-prefix=ALL --check-prefix=O32 %s
-// RUN: %clang -target mips64-unknown-linux   -S -o - -emit-llvm %s -mabi=n32 | FileCheck --check-prefix=ALL --check-prefix=N32 %s
-// RUN: %clang -target mips64el-unknown-linux -S -o - -emit-llvm %s -mabi=n32 | FileCheck --check-prefix=ALL --check-prefix=N32 %s
-// RUN: %clang -target mips64-unknown-linux   -S -o - -emit-llvm %s -mabi=64  | FileCheck --check-prefix=ALL --check-prefix=N64 %s
-// RUN: %clang -target mips64el-unknown-linux -S -o - -emit-llvm %s -mabi=64  | FileCheck --check-prefix=ALL --check-prefix=N64 %s
-
-int foo (int a, ...)
-{
-    // ALL-LABEL: define i32 @foo(i32 %a, ...)
-
-    __builtin_va_list va;
-    // O32: %va = alloca i8*, align 4
-    // N32: %va = alloca i8*, align 4
-    // N64: %va = alloca i8*, align 8
-
-    __builtin_va_start (va, a);
-    // ALL: %va1 = bitcast i8** %va to i8*
-    // ALL: call void @llvm.va_start(i8* %va1)
-
-    int n = __builtin_va_arg (va, int);
-    // ALL: %{{[0-9]+}} = va_arg i8** %va, i32
-    
-    __builtin_va_end (va);
-    // ALL: %va2 = bitcast i8** %va to i8*
-    // ALL: call void @llvm.va_end(i8* %va2)
-
-    return n;
-}