Attributes.cpp revision b0bc6c361da9009e8414efde317d9bbff755f6c0 
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::StackAlignment) {
74    Result += "alignstack(";
75    Result += utostr(Attribute::getStackAlignmentFromAttrs(Attrs));
76    Result += ") ";
77  }
78  if (Attrs & Attribute::Alignment) {
79    Result += "align ";
80    Result += utostr(Attribute::getAlignmentFromAttrs(Attrs));
81    Result += " ";
82  }
83  // Trim the trailing space.
84  assert(!Result.empty() && "Unknown attribute!");
85  Result.erase(Result.end()-1);
86  return Result;
87}
88
89Attributes Attribute::typeIncompatible(const Type *Ty) {
90  Attributes Incompatible = None;
91
92  if (!Ty->isIntegerTy())
93    // Attributes that only apply to integers.
94    Incompatible |= SExt | ZExt;
95
96  if (!isa<PointerType>(Ty))
97    // Attributes that only apply to pointers.
98    Incompatible |= ByVal | Nest | NoAlias | StructRet | NoCapture;
99
100  return Incompatible;
101}
102
103//===----------------------------------------------------------------------===//
104// AttributeListImpl Definition
105//===----------------------------------------------------------------------===//
106
107namespace llvm {
108class AttributeListImpl : public FoldingSetNode {
109  sys::cas_flag RefCount;
110
111  // AttributesList is uniqued, these should not be publicly available.
112  void operator=(const AttributeListImpl &); // Do not implement
113  AttributeListImpl(const AttributeListImpl &); // Do not implement
114  ~AttributeListImpl();                        // Private implementation
115public:
116  SmallVector<AttributeWithIndex, 4> Attrs;
117
118  AttributeListImpl(const AttributeWithIndex *Attr, unsigned NumAttrs)
119    : Attrs(Attr, Attr+NumAttrs) {
120    RefCount = 0;
121  }
122
123  void AddRef() { sys::AtomicIncrement(&RefCount); }
124  void DropRef() {
125    sys::cas_flag old = sys::AtomicDecrement(&RefCount);
126    if (old == 0) delete this;
127  }
128
129  void Profile(FoldingSetNodeID &ID) const {
130    Profile(ID, Attrs.data(), Attrs.size());
131  }
132  static void Profile(FoldingSetNodeID &ID, const AttributeWithIndex *Attr,
133                      unsigned NumAttrs) {
134    for (unsigned i = 0; i != NumAttrs; ++i)
135      ID.AddInteger(uint64_t(Attr[i].Attrs) << 32 | unsigned(Attr[i].Index));
136  }
137};
138}
139
140static ManagedStatic<sys::SmartMutex<true> > ALMutex;
141static ManagedStatic<FoldingSet<AttributeListImpl> > AttributesLists;
142
143AttributeListImpl::~AttributeListImpl() {
144  sys::SmartScopedLock<true> Lock(*ALMutex);
145  AttributesLists->RemoveNode(this);
146}
147
148
149AttrListPtr AttrListPtr::get(const AttributeWithIndex *Attrs, unsigned NumAttrs) {
150  // If there are no attributes then return a null AttributesList pointer.
151  if (NumAttrs == 0)
152    return AttrListPtr();
153
154#ifndef NDEBUG
155  for (unsigned i = 0; i != NumAttrs; ++i) {
156    assert(Attrs[i].Attrs != Attribute::None &&
157           "Pointless attribute!");
158    assert((!i || Attrs[i-1].Index < Attrs[i].Index) &&
159           "Misordered AttributesList!");
160  }
161#endif
162
163  // Otherwise, build a key to look up the existing attributes.
164  FoldingSetNodeID ID;
165  AttributeListImpl::Profile(ID, Attrs, NumAttrs);
166  void *InsertPos;
167
168  sys::SmartScopedLock<true> Lock(*ALMutex);
169
170  AttributeListImpl *PAL =
171    AttributesLists->FindNodeOrInsertPos(ID, InsertPos);
172
173  // If we didn't find any existing attributes of the same shape then
174  // create a new one and insert it.
175  if (!PAL) {
176    PAL = new AttributeListImpl(Attrs, NumAttrs);
177    AttributesLists->InsertNode(PAL, InsertPos);
178  }
179
180  // Return the AttributesList that we found or created.
181  return AttrListPtr(PAL);
182}
183
184
185//===----------------------------------------------------------------------===//
186// AttrListPtr Method Implementations
187//===----------------------------------------------------------------------===//
188
189AttrListPtr::AttrListPtr(AttributeListImpl *LI) : AttrList(LI) {
190  if (LI) LI->AddRef();
191}
192
193AttrListPtr::AttrListPtr(const AttrListPtr &P) : AttrList(P.AttrList) {
194  if (AttrList) AttrList->AddRef();
195}
196
197const AttrListPtr &AttrListPtr::operator=(const AttrListPtr &RHS) {
198  if (AttrList == RHS.AttrList) return *this;
199  if (AttrList) AttrList->DropRef();
200  AttrList = RHS.AttrList;
201  if (AttrList) AttrList->AddRef();
202  return *this;
203}
204
205AttrListPtr::~AttrListPtr() {
206  if (AttrList) AttrList->DropRef();
207}
208
209/// getNumSlots - Return the number of slots used in this attribute list.
210/// This is the number of arguments that have an attribute set on them
211/// (including the function itself).
212unsigned AttrListPtr::getNumSlots() const {
213  return AttrList ? AttrList->Attrs.size() : 0;
214}
215
216/// getSlot - Return the AttributeWithIndex at the specified slot.  This
217/// holds a number plus a set of attributes.
218const AttributeWithIndex &AttrListPtr::getSlot(unsigned Slot) const {
219  assert(AttrList && Slot < AttrList->Attrs.size() && "Slot # out of range!");
220  return AttrList->Attrs[Slot];
221}
222
223
224/// getAttributes - The attributes for the specified index are
225/// returned.  Attributes for the result are denoted with Idx = 0.
226/// Function notes are denoted with idx = ~0.
227Attributes AttrListPtr::getAttributes(unsigned Idx) const {
228  if (AttrList == 0) return Attribute::None;
229
230  const SmallVector<AttributeWithIndex, 4> &Attrs = AttrList->Attrs;
231  for (unsigned i = 0, e = Attrs.size(); i != e && Attrs[i].Index <= Idx; ++i)
232    if (Attrs[i].Index == Idx)
233      return Attrs[i].Attrs;
234  return Attribute::None;
235}
236
237/// hasAttrSomewhere - Return true if the specified attribute is set for at
238/// least one parameter or for the return value.
239bool AttrListPtr::hasAttrSomewhere(Attributes Attr) const {
240  if (AttrList == 0) return false;
241
242  const SmallVector<AttributeWithIndex, 4> &Attrs = AttrList->Attrs;
243  for (unsigned i = 0, e = Attrs.size(); i != e; ++i)
244    if (Attrs[i].Attrs & Attr)
245      return true;
246  return false;
247}
248
249
250AttrListPtr AttrListPtr::addAttr(unsigned Idx, Attributes Attrs) const {
251  Attributes OldAttrs = getAttributes(Idx);
252#ifndef NDEBUG
253  // FIXME it is not obvious how this should work for alignment.
254  // For now, say we can't change a known alignment.
255  Attributes OldAlign = OldAttrs & Attribute::Alignment;
256  Attributes NewAlign = Attrs & Attribute::Alignment;
257  assert((!OldAlign || !NewAlign || OldAlign == NewAlign) &&
258         "Attempt to change alignment!");
259#endif
260
261  Attributes NewAttrs = OldAttrs | Attrs;
262  if (NewAttrs == OldAttrs)
263    return *this;
264
265  SmallVector<AttributeWithIndex, 8> NewAttrList;
266  if (AttrList == 0)
267    NewAttrList.push_back(AttributeWithIndex::get(Idx, Attrs));
268  else {
269    const SmallVector<AttributeWithIndex, 4> &OldAttrList = AttrList->Attrs;
270    unsigned i = 0, e = OldAttrList.size();
271    // Copy attributes for arguments before this one.
272    for (; i != e && OldAttrList[i].Index < Idx; ++i)
273      NewAttrList.push_back(OldAttrList[i]);
274
275    // If there are attributes already at this index, merge them in.
276    if (i != e && OldAttrList[i].Index == Idx) {
277      Attrs |= OldAttrList[i].Attrs;
278      ++i;
279    }
280
281    NewAttrList.push_back(AttributeWithIndex::get(Idx, Attrs));
282
283    // Copy attributes for arguments after this one.
284    NewAttrList.insert(NewAttrList.end(),
285                       OldAttrList.begin()+i, OldAttrList.end());
286  }
287
288  return get(NewAttrList.data(), NewAttrList.size());
289}
290
291AttrListPtr AttrListPtr::removeAttr(unsigned Idx, Attributes Attrs) const {
292#ifndef NDEBUG
293  // FIXME it is not obvious how this should work for alignment.
294  // For now, say we can't pass in alignment, which no current use does.
295  assert(!(Attrs & Attribute::Alignment) && "Attempt to exclude alignment!");
296#endif
297  if (AttrList == 0) return AttrListPtr();
298
299  Attributes OldAttrs = getAttributes(Idx);
300  Attributes NewAttrs = OldAttrs & ~Attrs;
301  if (NewAttrs == OldAttrs)
302    return *this;
303
304  SmallVector<AttributeWithIndex, 8> NewAttrList;
305  const SmallVector<AttributeWithIndex, 4> &OldAttrList = AttrList->Attrs;
306  unsigned i = 0, e = OldAttrList.size();
307
308  // Copy attributes for arguments before this one.
309  for (; i != e && OldAttrList[i].Index < Idx; ++i)
310    NewAttrList.push_back(OldAttrList[i]);
311
312  // If there are attributes already at this index, merge them in.
313  assert(OldAttrList[i].Index == Idx && "Attribute isn't set?");
314  Attrs = OldAttrList[i].Attrs & ~Attrs;
315  ++i;
316  if (Attrs)  // If any attributes left for this parameter, add them.
317    NewAttrList.push_back(AttributeWithIndex::get(Idx, Attrs));
318
319  // Copy attributes for arguments after this one.
320  NewAttrList.insert(NewAttrList.end(),
321                     OldAttrList.begin()+i, OldAttrList.end());
322
323  return get(NewAttrList.data(), NewAttrList.size());
324}
325
326void AttrListPtr::dump() const {
327  dbgs() << "PAL[ ";
328  for (unsigned i = 0; i < getNumSlots(); ++i) {
329    const AttributeWithIndex &PAWI = getSlot(i);
330    dbgs() << "{" << PAWI.Index << "," << PAWI.Attrs << "} ";
331  }
332
333  dbgs() << "]\n";
334}
335