lib/VMCore/Attributes.cpp

   1 //===-- Attributes.cpp - Implement AttributesList -------------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file implements the AttributesList class and Attribute utilities.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/Attributes.h"
  15 #include "llvm/Type.h"
  16 #include "llvm/ADT/StringExtras.h"
  17 #include "llvm/ADT/FoldingSet.h"
  18 #include "llvm/Support/Streams.h"
  19 #include "llvm/Support/ManagedStatic.h"
  20 using namespace llvm;
  21
  22 //===----------------------------------------------------------------------===//
  23 // Attribute Function Definitions
  24 //===----------------------------------------------------------------------===//
  25
  26 std::string Attribute::getAsString(Attributes Attrs) {
  27   std::string Result;
  28   if (Attrs & Attribute::ZExt)
  29     Result += "zeroext ";
  30   if (Attrs & Attribute::SExt)
  31     Result += "signext ";
  32   if (Attrs & Attribute::NoReturn)
  33     Result += "noreturn ";
  34   if (Attrs & Attribute::NoUnwind)
  35     Result += "nounwind ";
  36   if (Attrs & Attribute::InReg)
  37     Result += "inreg ";
  38   if (Attrs & Attribute::NoAlias)
  39     Result += "noalias ";
  40   if (Attrs & Attribute::NoCapture)
  41     Result += "nocapture ";
  42   if (Attrs & Attribute::StructRet)
  43     Result += "sret ";
  44   if (Attrs & Attribute::ByVal)
  45     Result += "byval ";
  46   if (Attrs & Attribute::Nest)
  47     Result += "nest ";
  48   if (Attrs & Attribute::ReadNone)
  49     Result += "readnone ";
  50   if (Attrs & Attribute::ReadOnly)
  51     Result += "readonly ";
  52   if (Attrs & Attribute::OptimizeForSize)
  53     Result += "optsize ";
  54   if (Attrs & Attribute::NoInline)
  55     Result += "noinline ";
  56   if (Attrs & Attribute::AlwaysInline)
  57     Result += "alwaysinline ";
  58   if (Attrs & Attribute::StackProtect)
  59     Result += "ssp ";
  60   if (Attrs & Attribute::StackProtectReq)
  61     Result += "sspreq ";
  62   if (Attrs & Attribute::Alignment) {
  63     Result += "align ";
  64     Result += utostr(Attribute::getAlignmentFromAttrs(Attrs));
  65     Result += " ";
  66   }
  67   // Trim the trailing space.
  68   assert(!Result.empty() && "Unknown attribute!");
  69   Result.erase(Result.end()-1);
  70   return Result;
  71 }
  72
  73 Attributes Attribute::typeIncompatible(const Type *Ty) {
  74   Attributes Incompatible = None;
  75
  76   if (!Ty->isInteger())
  77     // Attributes that only apply to integers.
  78     Incompatible |= SExt | ZExt;
  79
  80   if (!isa<PointerType>(Ty))
  81     // Attributes that only apply to pointers.
  82     Incompatible |= ByVal | Nest | NoAlias | StructRet | NoCapture;
  83
  84   return Incompatible;
  85 }
  86
  87 //===----------------------------------------------------------------------===//
  88 // AttributeListImpl Definition
  89 //===----------------------------------------------------------------------===//
  90
  91 namespace llvm {
  92 class AttributeListImpl : public FoldingSetNode {
  93   unsigned RefCount;
  94
  95   // AttributesList is uniqued, these should not be publicly available.
  96   void operator=(const AttributeListImpl &); // Do not implement
  97   AttributeListImpl(const AttributeListImpl &); // Do not implement
  98   ~AttributeListImpl();                        // Private implementation
  99 public:
 100   SmallVector<AttributeWithIndex, 4> Attrs;
 101
 102   AttributeListImpl(const AttributeWithIndex *Attr, unsigned NumAttrs)
 103     : Attrs(Attr, Attr+NumAttrs) {
 104     RefCount = 0;
 105   }
 106
 107   void AddRef() { ++RefCount; }
 108   void DropRef() { if (--RefCount == 0) delete this; }
 109
 110   void Profile(FoldingSetNodeID &ID) const {
 111     Profile(ID, &Attrs[0], Attrs.size());
 112   }
 113   static void Profile(FoldingSetNodeID &ID, const AttributeWithIndex *Attr,
 114                       unsigned NumAttrs) {
 115     for (unsigned i = 0; i != NumAttrs; ++i)
 116       ID.AddInteger(uint64_t(Attr[i].Attrs) << 32 | unsigned(Attr[i].Index));
 117   }
 118 };
 119 }
 120
 121 static ManagedStatic<FoldingSet<AttributeListImpl> > AttributesLists;
 122
 123 AttributeListImpl::~AttributeListImpl() {
 124   AttributesLists->RemoveNode(this);
 125 }
 126
 127
 128 AttrListPtr AttrListPtr::get(const AttributeWithIndex *Attrs, unsigned NumAttrs) {
 129   // If there are no attributes then return a null AttributesList pointer.
 130   if (NumAttrs == 0)
 131     return AttrListPtr();
 132
 133 #ifndef NDEBUG
 134   for (unsigned i = 0; i != NumAttrs; ++i) {
 135     assert(Attrs[i].Attrs != Attribute::None &&
 136            "Pointless attribute!");
 137     assert((!i || Attrs[i-1].Index < Attrs[i].Index) &&
 138            "Misordered AttributesList!");
 139   }
 140 #endif
 141
 142   // Otherwise, build a key to look up the existing attributes.
 143   FoldingSetNodeID ID;
 144   AttributeListImpl::Profile(ID, Attrs, NumAttrs);
 145   void *InsertPos;
 146   AttributeListImpl *PAL =
 147     AttributesLists->FindNodeOrInsertPos(ID, InsertPos);
 148
 149   // If we didn't find any existing attributes of the same shape then
 150   // create a new one and insert it.
 151   if (!PAL) {
 152     PAL = new AttributeListImpl(Attrs, NumAttrs);
 153     AttributesLists->InsertNode(PAL, InsertPos);
 154   }
 155
 156   // Return the AttributesList that we found or created.
 157   return AttrListPtr(PAL);
 158 }
 159
 160
 161 //===----------------------------------------------------------------------===//
 162 // AttrListPtr Method Implementations
 163 //===----------------------------------------------------------------------===//
 164
 165 AttrListPtr::AttrListPtr(AttributeListImpl *LI) : AttrList(LI) {
 166   if (LI) LI->AddRef();
 167 }
 168
 169 AttrListPtr::AttrListPtr(const AttrListPtr &P) : AttrList(P.AttrList) {
 170   if (AttrList) AttrList->AddRef();
 171 }
 172
 173 const AttrListPtr &AttrListPtr::operator=(const AttrListPtr &RHS) {
 174   if (AttrList == RHS.AttrList) return *this;
 175   if (AttrList) AttrList->DropRef();
 176   AttrList = RHS.AttrList;
 177   if (AttrList) AttrList->AddRef();
 178   return *this;
 179 }
 180
 181 AttrListPtr::~AttrListPtr() {
 182   if (AttrList) AttrList->DropRef();
 183 }
 184
 185 /// getNumSlots - Return the number of slots used in this attribute list.
 186 /// This is the number of arguments that have an attribute set on them
 187 /// (including the function itself).
 188 unsigned AttrListPtr::getNumSlots() const {
 189   return AttrList ? AttrList->Attrs.size() : 0;
 190 }
 191
 192 /// getSlot - Return the AttributeWithIndex at the specified slot.  This
 193 /// holds a number plus a set of attributes.
 194 const AttributeWithIndex &AttrListPtr::getSlot(unsigned Slot) const {
 195   assert(AttrList && Slot < AttrList->Attrs.size() && "Slot # out of range!");
 196   return AttrList->Attrs[Slot];
 197 }
 198
 199
 200 /// getAttributes - The attributes for the specified index are
 201 /// returned.  Attributes for the result are denoted with Idx = 0.
 202 /// Function notes are denoted with idx = ~0.
 203 Attributes AttrListPtr::getAttributes(unsigned Idx) const {
 204   if (AttrList == 0) return Attribute::None;
 205
 206   const SmallVector<AttributeWithIndex, 4> &Attrs = AttrList->Attrs;
 207   for (unsigned i = 0, e = Attrs.size(); i != e && Attrs[i].Index <= Idx; ++i)
 208     if (Attrs[i].Index == Idx)
 209       return Attrs[i].Attrs;
 210   return Attribute::None;
 211 }
 212
 213 /// hasAttrSomewhere - Return true if the specified attribute is set for at
 214 /// least one parameter or for the return value.
 215 bool AttrListPtr::hasAttrSomewhere(Attributes Attr) const {
 216   if (AttrList == 0) return false;
 217
 218   const SmallVector<AttributeWithIndex, 4> &Attrs = AttrList->Attrs;
 219   for (unsigned i = 0, e = Attrs.size(); i != e; ++i)
 220     if (Attrs[i].Attrs & Attr)
 221       return true;
 222   return false;
 223 }
 224
 225
 226 AttrListPtr AttrListPtr::addAttr(unsigned Idx, Attributes Attrs) const {
 227   Attributes OldAttrs = getAttributes(Idx);
 228 #ifndef NDEBUG
 229   // FIXME it is not obvious how this should work for alignment.
 230   // For now, say we can't change a known alignment.
 231   Attributes OldAlign = OldAttrs & Attribute::Alignment;
 232   Attributes NewAlign = Attrs & Attribute::Alignment;
 233   assert((!OldAlign || !NewAlign || OldAlign == NewAlign) &&
 234          "Attempt to change alignment!");
 235 #endif
 236
 237   Attributes NewAttrs = OldAttrs | Attrs;
 238   if (NewAttrs == OldAttrs)
 239     return *this;
 240
 241   SmallVector<AttributeWithIndex, 8> NewAttrList;
 242   if (AttrList == 0)
 243     NewAttrList.push_back(AttributeWithIndex::get(Idx, Attrs));
 244   else {
 245     const SmallVector<AttributeWithIndex, 4> &OldAttrList = AttrList->Attrs;
 246     unsigned i = 0, e = OldAttrList.size();
 247     // Copy attributes for arguments before this one.
 248     for (; i != e && OldAttrList[i].Index < Idx; ++i)
 249       NewAttrList.push_back(OldAttrList[i]);
 250
 251     // If there are attributes already at this index, merge them in.
 252     if (i != e && OldAttrList[i].Index == Idx) {
 253       Attrs |= OldAttrList[i].Attrs;
 254       ++i;
 255     }
 256
 257     NewAttrList.push_back(AttributeWithIndex::get(Idx, Attrs));
 258
 259     // Copy attributes for arguments after this one.
 260     NewAttrList.insert(NewAttrList.end(),
 261                        OldAttrList.begin()+i, OldAttrList.end());
 262   }
 263
 264   return get(&NewAttrList[0], NewAttrList.size());
 265 }
 266
 267 AttrListPtr AttrListPtr::removeAttr(unsigned Idx, Attributes Attrs) const {
 268 #ifndef NDEBUG
 269   // FIXME it is not obvious how this should work for alignment.
 270   // For now, say we can't pass in alignment, which no current use does.
 271   assert(!(Attrs & Attribute::Alignment) && "Attempt to exclude alignment!");
 272 #endif
 273   if (AttrList == 0) return AttrListPtr();
 274
 275   Attributes OldAttrs = getAttributes(Idx);
 276   Attributes NewAttrs = OldAttrs & ~Attrs;
 277   if (NewAttrs == OldAttrs)
 278     return *this;
 279
 280   SmallVector<AttributeWithIndex, 8> NewAttrList;
 281   const SmallVector<AttributeWithIndex, 4> &OldAttrList = AttrList->Attrs;
 282   unsigned i = 0, e = OldAttrList.size();
 283
 284   // Copy attributes for arguments before this one.
 285   for (; i != e && OldAttrList[i].Index < Idx; ++i)
 286     NewAttrList.push_back(OldAttrList[i]);
 287
 288   // If there are attributes already at this index, merge them in.
 289   assert(OldAttrList[i].Index == Idx && "Attribute isn't set?");
 290   Attrs = OldAttrList[i].Attrs & ~Attrs;
 291   ++i;
 292   if (Attrs)  // If any attributes left for this parameter, add them.
 293     NewAttrList.push_back(AttributeWithIndex::get(Idx, Attrs));
 294
 295   // Copy attributes for arguments after this one.
 296   NewAttrList.insert(NewAttrList.end(),
 297                      OldAttrList.begin()+i, OldAttrList.end());
 298
 299   return get(&NewAttrList[0], NewAttrList.size());
 300 }
 301
 302 void AttrListPtr::dump() const {
 303   cerr << "PAL[ ";
 304   for (unsigned i = 0; i < getNumSlots(); ++i) {
 305     const AttributeWithIndex &PAWI = getSlot(i);
 306     cerr << "{" << PAWI.Index << "," << PAWI.Attrs << "} ";
 307   }
 308
 309   cerr << "]\n";
 310 }