r214497 - [mips] Defer va_arg expansion to the backend.

[Daniel Sanders]

Author: dsanders
Date: Fri Aug  1 05:29:21 2014
New Revision: 214497

URL: http://llvm.org/viewvc/llvm-project?rev=214497&view=rev
Log:
[mips] Defer va_arg expansion to the backend.

Summary:
This patch causes clang to emit va_arg instructions to the backend instead of
expanding them into an implementation itself. The backend already implements
va_arg since this is necessary for NaCl so this patch is removing redundant
code.

Together with the llvm patch (D4556) that accounts for the effect of endianness
on the expansion of va_arg, this fixes PR19612.

Depends on D4556

Reviewers: sstankovic, dsanders

Reviewed By: dsanders

Subscribers: rnk, cfe-commits

Differential Revision: http://reviews.llvm.org/D4742

Added:
    cfe/trunk/test/CodeGen/mips-vaarg.c
Modified:
    cfe/trunk/lib/CodeGen/TargetInfo.cpp

Modified: cfe/trunk/lib/CodeGen/TargetInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/TargetInfo.cpp?rev=214497&r1=214496&r2=214497&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/TargetInfo.cpp (original)
+++ cfe/trunk/lib/CodeGen/TargetInfo.cpp Fri Aug  1 05:29:21 2014
@@ -5560,39 +5560,7 @@ void MipsABIInfo::computeInfo(CGFunction
 
 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

Added: cfe/trunk/test/CodeGen/mips-vaarg.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/mips-vaarg.c?rev=214497&view=auto
==============================================================================
--- cfe/trunk/test/CodeGen/mips-vaarg.c (added)
+++ cfe/trunk/test/CodeGen/mips-vaarg.c Fri Aug  1 05:29:21 2014
@@ -0,0 +1,29 @@
+// 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;
+}