Prep for merging 3.4: Undo changes from 3.3 branch

lib/Basic/Targets.cpp

 //===--- Targets.cpp - Implement -arch option and targets -----------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements construction of a TargetInfo object from a
@@ skipping 3511 matching lines @@
 
   unsigned IsAAPCS : 1;
   unsigned IsThumb : 1;
 
   // Initialized via features.
   unsigned SoftFloat : 1;
   unsigned SoftFloatABI : 1;
 
   static const Builtin::Info BuiltinInfo[];
 
-  static bool shouldUseInlineAtomic(const llvm::Triple &T) {
-    // On linux, binaries targeting old cpus call functions in libgcc to
-    // perform atomic operations. The implementation in libgcc then calls into
-    // the kernel which on armv6 and newer uses ldrex and strex. The net result
-    // is that if we assume the kernel is at least as recent as the hardware,
-    // it is safe to use atomic instructions on armv6 and newer.
-    if (T.getOS() != llvm::Triple::Linux)
-     return false;
-    StringRef ArchName = T.getArchName();
-    if (T.getArch() == llvm::Triple::arm) {
-      if (!ArchName.startswith("armv"))
-        return false;
-      StringRef VersionStr = ArchName.substr(4);
-      unsigned Version;
-      if (VersionStr.getAsInteger(10, Version))
-        return false;
-      return Version >= 6;
-    }
-    assert(T.getArch() == llvm::Triple::thumb);
-    if (!ArchName.startswith("thumbv"))
-      return false;
-    StringRef VersionStr = ArchName.substr(6);
-    unsigned Version;
-    if (VersionStr.getAsInteger(10, Version))
-      return false;
-    return Version >= 7;
-  }
-
 public:
   ARMTargetInfo(const std::string &TripleStr)
     : TargetInfo(TripleStr), ABI("aapcs-linux"), CPU("arm1136j-s"), IsAAPCS(true)
   {
     BigEndian = false;
     SizeType = UnsignedInt;
     PtrDiffType = SignedInt;
     // AAPCS 7.1.1, ARM-Linux ABI 2.4: type of wchar_t is unsigned int.
     WCharType = UnsignedInt;
 
@@ skipping 12 matching lines @@
     } else {
       DescriptionString = ("e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-"
                            "i64:64:64-f32:32:32-f64:64:64-"
                            "v64:64:64-v128:64:128-a0:0:64-n32-S64");
     }
 
     // ARM targets default to using the ARM C++ ABI.
     TheCXXABI.set(TargetCXXABI::GenericARM);
 
     // ARM has atomics up to 8 bytes
+    // FIXME: Set MaxAtomicInlineWidth if we have the feature v6e
     MaxAtomicPromoteWidth = 64;
-    if (shouldUseInlineAtomic(getTriple()))
-      MaxAtomicInlineWidth = 64;
 
     // Do force alignment of members that follow zero length bitfields.  If
     // the alignment of the zero-length bitfield is greater than the member 
     // that follows it, `bar', `bar' will be aligned as the  type of the 
     // zero length bitfield.
     UseZeroLengthBitfieldAlignment = true;
   }
   virtual const char *getABI() const { return ABI.c_str(); }
   virtual bool setABI(const std::string &Name) {
     ABI = Name;
@@ skipping 1977 matching lines @@
   // FIXME: If we are completely confident that we have the right set, we only
   // need to pass the minuses.
   Opts->Features.clear();
   for (llvm::StringMap<bool>::const_iterator it = Features.begin(),
          ie = Features.end(); it != ie; ++it)
     Opts->Features.push_back((it->second ? "+" : "-") + it->first().str());
   Target->HandleTargetFeatures(Opts->Features);
 
   return Target.take();
 }