r211216 - CodeGen: improve ms instrincics support

Reid Kleckner rnk at google.com
Fri Jun 20 13:38:00 PDT 2014


Remember how I said it'd be OK if we provided
_InterlockedCompareExchangePointer on x86?  Well, doing that broke the
sanitizers.  Do 'check-asan' on 32-bit Windows to reproduce.

This is the problematic code:
inline static void *_InterlockedCompareExchangePointer(
    void *volatile *Destination,
    void *Exchange, void *Comparand) {
  return reinterpret_cast<void*>(
      _InterlockedCompareExchange(
          reinterpret_cast<long volatile*>(Destination),  // NOLINT
          reinterpret_cast<long>(Exchange),               // NOLINT
          reinterpret_cast<long>(Comparand)));            // NOLINT
}


On Wed, Jun 18, 2014 at 1:51 PM, Saleem Abdulrasool <compnerd at compnerd.org>
wrote:

> Author: compnerd
> Date: Wed Jun 18 15:51:10 2014
> New Revision: 211216
>
> URL: http://llvm.org/viewvc/llvm-project?rev=211216&view=rev
> Log:
> CodeGen: improve ms instrincics support
>
> Add support for _InterlockedCompareExchangePointer,
> _InterlockExchangePointer,
> _InterlockExchange.  These are available as a compiler intrinsic on ARM
> and x86.
> These are used directly by the Windows SDK headers without use of the
> intrin
> header.
>
> Added:
>     cfe/trunk/test/CodeGen/ms-intrinsics.c
> Modified:
>     cfe/trunk/include/clang/Basic/Builtins.def
>     cfe/trunk/lib/CodeGen/CGBuiltin.cpp
>     cfe/trunk/lib/Headers/Intrin.h
>
> Modified: cfe/trunk/include/clang/Basic/Builtins.def
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/Builtins.def?rev=211216&r1=211215&r2=211216&view=diff
>
> ==============================================================================
> --- cfe/trunk/include/clang/Basic/Builtins.def (original)
> +++ cfe/trunk/include/clang/Basic/Builtins.def Wed Jun 18 15:51:10 2014
> @@ -683,9 +683,12 @@ LANGBUILTIN(__noop,       "v.",  "n", AL
>  LANGBUILTIN(__debugbreak, "v",   "n", ALL_MS_LANGUAGES)
>  LANGBUILTIN(__va_start,   "vc**.", "nt", ALL_MS_LANGUAGES)
>  LANGBUILTIN(_InterlockedCompareExchange, "LiLiD*LiLi", "n",
> ALL_MS_LANGUAGES)
> +LANGBUILTIN(_InterlockedCompareExchangePointer, "v*v*D*v*v*", "n",
> ALL_MS_LANGUAGES)
>  LANGBUILTIN(_InterlockedIncrement, "LiLiD*", "n", ALL_MS_LANGUAGES)
>  LANGBUILTIN(_InterlockedDecrement, "LiLiD*", "n", ALL_MS_LANGUAGES)
>  LANGBUILTIN(_InterlockedExchangeAdd, "LiLiD*Li", "n", ALL_MS_LANGUAGES)
> +LANGBUILTIN(_InterlockedExchangePointer, "v*v*D*v*", "n",
> ALL_MS_LANGUAGES)
> +LANGBUILTIN(_InterlockedExchange, "LiLiD*Li", "n", ALL_MS_LANGUAGES)
>
>  // C99 library functions
>  // C99 stdlib.h
>
> Modified: cfe/trunk/lib/CodeGen/CGBuiltin.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGBuiltin.cpp?rev=211216&r1=211215&r2=211216&view=diff
>
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CGBuiltin.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CGBuiltin.cpp Wed Jun 18 15:51:10 2014
> @@ -1516,6 +1516,35 @@ RValue CodeGenFunction::EmitBuiltinExpr(
>                                      E->getArg(0), true);
>    case Builtin::BI__noop:
>      return RValue::get(nullptr);
> +  case Builtin::BI_InterlockedExchange:
> +  case Builtin::BI_InterlockedExchangePointer:
> +    return EmitBinaryAtomic(*this, llvm::AtomicRMWInst::Xchg, E);
> +  case Builtin::BI_InterlockedCompareExchangePointer: {
> +    llvm::Type *RTy;
> +    llvm::IntegerType *IntType =
> +      IntegerType::get(getLLVMContext(),
> +                       getContext().getTypeSize(E->getType()));
> +    llvm::Type *IntPtrType = IntType->getPointerTo();
> +
> +    llvm::Value *Destination =
> +      Builder.CreateBitCast(EmitScalarExpr(E->getArg(0)), IntPtrType);
> +
> +    llvm::Value *Exchange = EmitScalarExpr(E->getArg(1));
> +    RTy = Exchange->getType();
> +    Exchange = Builder.CreatePtrToInt(Exchange, IntType);
> +
> +    llvm::Value *Comparand =
> +      Builder.CreatePtrToInt(EmitScalarExpr(E->getArg(2)), IntType);
> +
> +    auto Result = Builder.CreateAtomicCmpXchg(Destination, Comparand,
> Exchange,
> +                                              SequentiallyConsistent,
> +                                              SequentiallyConsistent);
> +    Result->setVolatile(true);
> +
> +    return
> RValue::get(Builder.CreateIntToPtr(Builder.CreateExtractValue(Result,
> +
> 0),
> +                                              RTy));
> +  }
>    case Builtin::BI_InterlockedCompareExchange: {
>      AtomicCmpXchgInst *CXI = Builder.CreateAtomicCmpXchg(
>          EmitScalarExpr(E->getArg(0)),
>
> Modified: cfe/trunk/lib/Headers/Intrin.h
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Headers/Intrin.h?rev=211216&r1=211215&r2=211216&view=diff
>
> ==============================================================================
> --- cfe/trunk/lib/Headers/Intrin.h (original)
> +++ cfe/trunk/lib/Headers/Intrin.h Wed Jun 18 15:51:10 2014
> @@ -223,8 +223,7 @@ static __inline__
>  long __cdecl _InterlockedDecrement(long volatile *_Addend);
>  static __inline__
>  short _InterlockedDecrement16(short volatile *_Addend);
> -static __inline__
> -long __cdecl _InterlockedExchange(long volatile *_Target, long _Value);
> +long _InterlockedExchange(long volatile *_Target, long _Value);
>  static __inline__
>  short _InterlockedExchange16(short volatile *_Target, short _Value);
>  static __inline__
> @@ -411,7 +410,6 @@ __int64 _InterlockedCompareExchange64_HL
>                                                   __int64);
>  __int64 _InterlockedCompareExchange64_np(__int64 volatile *_Destination,
>                                           __int64 _Exchange, __int64
> _Comparand);
> -static __inline__
>  void *_InterlockedCompareExchangePointer(void *volatile *_Destination,
>                                           void *_Exchange, void
> *_Comparand);
>  void *_InterlockedCompareExchangePointer_np(void *volatile *_Destination,
> @@ -422,7 +420,6 @@ static __inline__
>  __int64 _InterlockedExchange64(__int64 volatile *_Target, __int64 _Value);
>  static __inline__
>  __int64 _InterlockedExchangeAdd64(__int64 volatile *_Addend, __int64
> _Value);
> -static __inline__
>  void *_InterlockedExchangePointer(void *volatile *_Target, void *_Value);
>  static __inline__
>  __int64 _InterlockedIncrement64(__int64 volatile *_Addend);
> @@ -785,22 +782,12 @@ _InterlockedExchange16(short volatile *_
>    __atomic_exchange(_Target, &_Value, &_Value, 0);
>    return _Value;
>  }
> -static __inline__ long __attribute__((__always_inline__, __nodebug__))
> -_InterlockedExchange(long volatile *_Target, long _Value) {
> -  __atomic_exchange(_Target, &_Value, &_Value, 0);
> -  return _Value;
> -}
>  #ifdef __x86_64__
>  static __inline__ __int64 __attribute__((__always_inline__, __nodebug__))
>  _InterlockedExchange64(__int64 volatile *_Target, __int64 _Value) {
>    __atomic_exchange(_Target, &_Value, &_Value, 0);
>    return _Value;
>  }
> -static __inline__ void *__attribute__((__always_inline__, __nodebug__))
> -_InterlockedExchangePointer(void *volatile *_Target, void *_Value) {
> -  __atomic_exchange(_Target, &_Value, &_Value, 0);
> -  return _Value;
> -}
>  #endif
>
>  /*----------------------------------------------------------------------------*\
>  |* Interlocked Compare Exchange
> @@ -817,14 +804,6 @@ _InterlockedCompareExchange16(short vola
>    __atomic_compare_exchange(_Destination, &_Comparand, &_Exchange, 0, 0,
> 0);
>    return _Comparand;
>  }
> -#ifdef __x86_64__
> -static __inline__ void *__attribute__((__always_inline__, __nodebug__))
> -_InterlockedCompareExchangePointer(void *volatile *_Destination,
> -                                   void *_Exchange, void *_Comparand) {
> -  __atomic_compare_exchange(_Destination, &_Comparand, &_Exchange, 0, 0,
> 0);
> -  return _Comparand;
> -}
> -#endif
>  static __inline__ __int64 __attribute__((__always_inline__, __nodebug__))
>  _InterlockedCompareExchange64(__int64 volatile *_Destination,
>                                __int64 _Exchange, __int64 _Comparand) {
>
> Added: cfe/trunk/test/CodeGen/ms-intrinsics.c
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/ms-intrinsics.c?rev=211216&view=auto
>
> ==============================================================================
> --- cfe/trunk/test/CodeGen/ms-intrinsics.c (added)
> +++ cfe/trunk/test/CodeGen/ms-intrinsics.c Wed Jun 18 15:51:10 2014
> @@ -0,0 +1,41 @@
> +// RUN: %clang_cc1 -triple i686--windows -fms-compatibility -Oz
> -emit-llvm %s -o - | FileCheck %s
> +// RUN: %clang_cc1 -triple thumbv7--windows -fms-compatibility -Oz
> -emit-llvm %s -o - | FileCheck %s
> +
> +void *test_InterlockedExchangePointer(void * volatile *Target, void
> *Value) {
> +  return _InterlockedExchangePointer(Target, Value);
> +}
> +
> +// CHECK: define{{.*}}i8* @test_InterlockedExchangePointer(i8** %Target,
> i8* %Value){{.*}}{
> +// CHECK: entry:
> +// CHECK:   %0 = bitcast i8** %Target to i32*
> +// CHECK:   %1 = ptrtoint i8* %Value to i32
> +// CHECK:   %2 = atomicrmw xchg i32* %0, i32 %1 seq_cst
> +// CHECK:   %3 = inttoptr i32 %2 to i8*
> +// CHECK:   ret i8* %3
> +// CHECK: }
> +
> +void *test_InterlockedCompareExchangePointer(void * volatile *Destination,
> +                                             void *Exchange, void
> *Comparand) {
> +  return _InterlockedCompareExchangePointer(Destination, Exchange,
> Comparand);
> +}
> +
> +// CHECK: define{{.*}}i8* @test_InterlockedCompareExchangePointer(i8**
> %Destination, i8* %Exchange, i8* %Comparand){{.*}}{
> +// CHECK: entry:
> +// CHECK:   %0 = bitcast i8** %Destination to i32*
> +// CHECK:   %1 = ptrtoint i8* %Exchange to i32
> +// CHECK:   %2 = ptrtoint i8* %Comparand to i32
> +// CHECK:   %3 = cmpxchg volatile i32* %0, i32 %2, i32 %1 seq_cst seq_cst
> +// CHECK:   %4 = extractvalue { i32, i1 } %3, 0
> +// CHECK:   %5 = inttoptr i32 %4 to i8*
> +// CHECK:   ret i8* %5
> +// CHECK: }
> +
> +long test_InterlockedExchange(long *Target, long Value) {
> +  return _InterlockedExchange(Target, Value);
> +}
> +
> +// CHECK: define{{.*}}i32 @test_InterlockedExchange(i32* %Target, i32
> %Value){{.*}}{
> +// CHECK: entry:
> +// CHECK:   %0 = atomicrmw xchg i32* %Target, i32 %Value seq_cst
> +// CHECK:   ret i32 %0
> +// CHECK: }
>
>
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