Attributes.cpp revision ef1894ed7ec56875ee4f8ed0f7498abacc913c06 
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/System/Atomic.h"
19#include "llvm/System/Mutex.h"
20#include "llvm/Support/Debug.h"
21#include "llvm/Support/ManagedStatic.h"
22#include "llvm/Support/raw_ostream.h"
23using namespace llvm;
24
25//===----------------------------------------------------------------------===//
26// Attribute Function Definitions
27//===----------------------------------------------------------------------===//
28
29std::string Attribute::getAsString(Attributes Attrs) {
30  std::string Result;
31  if (Attrs & Attribute::ZExt)
32    Result += "zeroext ";
33  if (Attrs & Attribute::SExt)
34    Result += "signext ";
35  if (Attrs & Attribute::NoReturn)
36    Result += "noreturn ";
37  if (Attrs & Attribute::NoUnwind)
38    Result += "nounwind ";
39  if (Attrs & Attribute::InReg)
40    Result += "inreg ";
41  if (Attrs & Attribute::NoAlias)
42    Result += "noalias ";
43  if (Attrs & Attribute::NoCapture)
44    Result += "nocapture ";
45  if (Attrs & Attribute::StructRet)
46    Result += "sret ";
47  if (Attrs & Attribute::ByVal)
48    Result += "byval ";
49  if (Attrs & Attribute::Nest)
50    Result += "nest ";
51  if (Attrs & Attribute::ReadNone)
52    Result += "readnone ";
53  if (Attrs & Attribute::ReadOnly)
54    Result += "readonly ";
55  if (Attrs & Attribute::OptimizeForSize)
56    Result += "optsize ";
57  if (Attrs & Attribute::NoInline)
58    Result += "noinline ";
59  if (Attrs & Attribute::InlineHint)
60    Result += "inlinehint ";
61  if (Attrs & Attribute::AlwaysInline)
62    Result += "alwaysinline ";
63  if (Attrs & Attribute::StackProtect)
64    Result += "ssp ";
65  if (Attrs & Attribute::StackProtectReq)
66    Result += "sspreq ";
67  if (Attrs & Attribute::NoRedZone)
68    Result += "noredzone ";
69  if (Attrs & Attribute::NoImplicitFloat)
70    Result += "noimplicitfloat ";
71  if (Attrs & Attribute::Naked)
72    Result += "naked ";
73  if (Attrs & Attribute::Alignment) {
74    Result += "align ";
75    Result += utostr(Attribute::getAlignmentFromAttrs(Attrs));
76    Result += " ";
77  }
78  // Trim the trailing space.
79  assert(!Result.empty() && "Unknown attribute!");
80  Result.erase(Result.end()-1);
81  return Result;
82}
83
84Attributes Attribute::typeIncompatible(const Type *Ty) {
85  Attributes Incompatible = None;
86
87  if (!Ty->isInteger())
88    // Attributes that only apply to integers.
89    Incompatible |= SExt | ZExt;
90
91  if (!isa<PointerType>(Ty))
92    // Attributes that only apply to pointers.
93    Incompatible |= ByVal | Nest | NoAlias | StructRet | NoCapture;
94
95  return Incompatible;
96}
97
98//===----------------------------------------------------------------------===//
99// AttributeListImpl Definition
100//===----------------------------------------------------------------------===//
101
102namespace llvm {
103class AttributeListImpl : public FoldingSetNode {
104  sys::cas_flag RefCount;
105
106  // AttributesList is uniqued, these should not be publicly available.
107  void operator=(const AttributeListImpl &); // Do not implement
108  AttributeListImpl(const AttributeListImpl &); // Do not implement
109  ~AttributeListImpl();                        // Private implementation
110public:
111  SmallVector<AttributeWithIndex, 4> Attrs;
112
113  AttributeListImpl(const AttributeWithIndex *Attr, unsigned NumAttrs)
114    : Attrs(Attr, Attr+NumAttrs) {
115    RefCount = 0;
116  }
117
118  void AddRef() { sys::AtomicIncrement(&RefCount); }
119  void DropRef() {
120    sys::cas_flag old = sys::AtomicDecrement(&RefCount);
121    if (old == 0) delete this;
122  }
123
124  void Profile(FoldingSetNodeID &ID) const {
125    Profile(ID, Attrs.data(), Attrs.size());
126  }
127  static void Profile(FoldingSetNodeID &ID, const AttributeWithIndex *Attr,
128                      unsigned NumAttrs) {
129    for (unsigned i = 0; i != NumAttrs; ++i)
130      ID.AddInteger(uint64_t(Attr[i].Attrs) << 32 | unsigned(Attr[i].Index));
131  }
132};
133}
134
135static ManagedStatic<sys::SmartMutex<true> > ALMutex;
136static ManagedStatic<FoldingSet<AttributeListImpl> > AttributesLists;
137
138AttributeListImpl::~AttributeListImpl() {
139  sys::SmartScopedLock<true> Lock(*ALMutex);
140  AttributesLists->RemoveNode(this);
141}
142
143
144AttrListPtr AttrListPtr::get(const AttributeWithIndex *Attrs, unsigned NumAttrs) {
145  // If there are no attributes then return a null AttributesList pointer.
146  if (NumAttrs == 0)
147    return AttrListPtr();
148
149#ifndef NDEBUG
150  for (unsigned i = 0; i != NumAttrs; ++i) {
151    assert(Attrs[i].Attrs != Attribute::None &&
152           "Pointless attribute!");
153    assert((!i || Attrs[i-1].Index < Attrs[i].Index) &&
154           "Misordered AttributesList!");
155  }
156#endif
157
158  // Otherwise, build a key to look up the existing attributes.
159  FoldingSetNodeID ID;
160  AttributeListImpl::Profile(ID, Attrs, NumAttrs);
161  void *InsertPos;
162
163  sys::SmartScopedLock<true> Lock(*ALMutex);
164
165  AttributeListImpl *PAL =
166    AttributesLists->FindNodeOrInsertPos(ID, InsertPos);
167
168  // If we didn't find any existing attributes of the same shape then
169  // create a new one and insert it.
170  if (!PAL) {
171    PAL = new AttributeListImpl(Attrs, NumAttrs);
172    AttributesLists->InsertNode(PAL, InsertPos);
173  }
174
175  // Return the AttributesList that we found or created.
176  return AttrListPtr(PAL);
177}
178
179
180//===----------------------------------------------------------------------===//
181// AttrListPtr Method Implementations
182//===----------------------------------------------------------------------===//
183
184AttrListPtr::AttrListPtr(AttributeListImpl *LI) : AttrList(LI) {
185  if (LI) LI->AddRef();
186}
187
188AttrListPtr::AttrListPtr(const AttrListPtr &P) : AttrList(P.AttrList) {
189  if (AttrList) AttrList->AddRef();
190}
191
192const AttrListPtr &AttrListPtr::operator=(const AttrListPtr &RHS) {
193  if (AttrList == RHS.AttrList) return *this;
194  if (AttrList) AttrList->DropRef();
195  AttrList = RHS.AttrList;
196  if (AttrList) AttrList->AddRef();
197  return *this;
198}
199
200AttrListPtr::~AttrListPtr() {
201  if (AttrList) AttrList->DropRef();
202}
203
204/// getNumSlots - Return the number of slots used in this attribute list.
205/// This is the number of arguments that have an attribute set on them
206/// (including the function itself).
207unsigned AttrListPtr::getNumSlots() const {
208  return AttrList ? AttrList->Attrs.size() : 0;
209}
210
211/// getSlot - Return the AttributeWithIndex at the specified slot.  This
212/// holds a number plus a set of attributes.
213const AttributeWithIndex &AttrListPtr::getSlot(unsigned Slot) const {
214  assert(AttrList && Slot < AttrList->Attrs.size() && "Slot # out of range!");
215  return AttrList->Attrs[Slot];
216}
217
218
219/// getAttributes - The attributes for the specified index are
220/// returned.  Attributes for the result are denoted with Idx = 0.
221/// Function notes are denoted with idx = ~0.
222Attributes AttrListPtr::getAttributes(unsigned Idx) const {
223  if (AttrList == 0) return Attribute::None;
224
225  const SmallVector<AttributeWithIndex, 4> &Attrs = AttrList->Attrs;
226  for (unsigned i = 0, e = Attrs.size(); i != e && Attrs[i].Index <= Idx; ++i)
227    if (Attrs[i].Index == Idx)
228      return Attrs[i].Attrs;
229  return Attribute::None;
230}
231
232/// hasAttrSomewhere - Return true if the specified attribute is set for at
233/// least one parameter or for the return value.
234bool AttrListPtr::hasAttrSomewhere(Attributes Attr) const {
235  if (AttrList == 0) return false;
236
237  const SmallVector<AttributeWithIndex, 4> &Attrs = AttrList->Attrs;
238  for (unsigned i = 0, e = Attrs.size(); i != e; ++i)
239    if (Attrs[i].Attrs & Attr)
240      return true;
241  return false;
242}
243
244
245AttrListPtr AttrListPtr::addAttr(unsigned Idx, Attributes Attrs) const {
246  Attributes OldAttrs = getAttributes(Idx);
247#ifndef NDEBUG
248  // FIXME it is not obvious how this should work for alignment.
249  // For now, say we can't change a known alignment.
250  Attributes OldAlign = OldAttrs & Attribute::Alignment;
251  Attributes NewAlign = Attrs & Attribute::Alignment;
252  assert((!OldAlign || !NewAlign || OldAlign == NewAlign) &&
253         "Attempt to change alignment!");
254#endif
255
256  Attributes NewAttrs = OldAttrs | Attrs;
257  if (NewAttrs == OldAttrs)
258    return *this;
259
260  SmallVector<AttributeWithIndex, 8> NewAttrList;
261  if (AttrList == 0)
262    NewAttrList.push_back(AttributeWithIndex::get(Idx, Attrs));
263  else {
264    const SmallVector<AttributeWithIndex, 4> &OldAttrList = AttrList->Attrs;
265    unsigned i = 0, e = OldAttrList.size();
266    // Copy attributes for arguments before this one.
267    for (; i != e && OldAttrList[i].Index < Idx; ++i)
268      NewAttrList.push_back(OldAttrList[i]);
269
270    // If there are attributes already at this index, merge them in.
271    if (i != e && OldAttrList[i].Index == Idx) {
272      Attrs |= OldAttrList[i].Attrs;
273      ++i;
274    }
275
276    NewAttrList.push_back(AttributeWithIndex::get(Idx, Attrs));
277
278    // Copy attributes for arguments after this one.
279    NewAttrList.insert(NewAttrList.end(),
280                       OldAttrList.begin()+i, OldAttrList.end());
281  }
282
283  return get(NewAttrList.data(), NewAttrList.size());
284}
285
286AttrListPtr AttrListPtr::removeAttr(unsigned Idx, Attributes Attrs) const {
287#ifndef NDEBUG
288  // FIXME it is not obvious how this should work for alignment.
289  // For now, say we can't pass in alignment, which no current use does.
290  assert(!(Attrs & Attribute::Alignment) && "Attempt to exclude alignment!");
291#endif
292  if (AttrList == 0) return AttrListPtr();
293
294  Attributes OldAttrs = getAttributes(Idx);
295  Attributes NewAttrs = OldAttrs & ~Attrs;
296  if (NewAttrs == OldAttrs)
297    return *this;
298
299  SmallVector<AttributeWithIndex, 8> NewAttrList;
300  const SmallVector<AttributeWithIndex, 4> &OldAttrList = AttrList->Attrs;
301  unsigned i = 0, e = OldAttrList.size();
302
303  // Copy attributes for arguments before this one.
304  for (; i != e && OldAttrList[i].Index < Idx; ++i)
305    NewAttrList.push_back(OldAttrList[i]);
306
307  // If there are attributes already at this index, merge them in.
308  assert(OldAttrList[i].Index == Idx && "Attribute isn't set?");
309  Attrs = OldAttrList[i].Attrs & ~Attrs;
310  ++i;
311  if (Attrs)  // If any attributes left for this parameter, add them.
312    NewAttrList.push_back(AttributeWithIndex::get(Idx, Attrs));
313
314  // Copy attributes for arguments after this one.
315  NewAttrList.insert(NewAttrList.end(),
316                     OldAttrList.begin()+i, OldAttrList.end());
317
318  return get(NewAttrList.data(), NewAttrList.size());
319}
320
321void AttrListPtr::dump() const {
322  dbgs() << "PAL[ ";
323  for (unsigned i = 0; i < getNumSlots(); ++i) {
324    const AttributeWithIndex &PAWI = getSlot(i);
325    dbgs() << "{" << PAWI.Index << "," << PAWI.Attrs << "} ";
326  }
327
328  dbgs() << "]\n";
329}
330