Attributes.cpp revision 596c1dc3e228795562975396bcd9672840aa3c82 
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/Mutex.h"
19#include "llvm/Support/Streams.h"
20#include "llvm/Support/ManagedStatic.h"
21using namespace llvm;
22
23//===----------------------------------------------------------------------===//
24// Attribute Function Definitions
25//===----------------------------------------------------------------------===//
26
27std::string Attribute::getAsString(Attributes Attrs) {
28  std::string Result;
29  if (Attrs & Attribute::ZExt)
30    Result += "zeroext ";
31  if (Attrs & Attribute::SExt)
32    Result += "signext ";
33  if (Attrs & Attribute::NoReturn)
34    Result += "noreturn ";
35  if (Attrs & Attribute::NoUnwind)
36    Result += "nounwind ";
37  if (Attrs & Attribute::InReg)
38    Result += "inreg ";
39  if (Attrs & Attribute::NoAlias)
40    Result += "noalias ";
41  if (Attrs & Attribute::NoCapture)
42    Result += "nocapture ";
43  if (Attrs & Attribute::StructRet)
44    Result += "sret ";
45  if (Attrs & Attribute::ByVal)
46    Result += "byval ";
47  if (Attrs & Attribute::Nest)
48    Result += "nest ";
49  if (Attrs & Attribute::ReadNone)
50    Result += "readnone ";
51  if (Attrs & Attribute::ReadOnly)
52    Result += "readonly ";
53  if (Attrs & Attribute::OptimizeForSize)
54    Result += "optsize ";
55  if (Attrs & Attribute::NoInline)
56    Result += "noinline ";
57  if (Attrs & Attribute::AlwaysInline)
58    Result += "alwaysinline ";
59  if (Attrs & Attribute::StackProtect)
60    Result += "ssp ";
61  if (Attrs & Attribute::StackProtectReq)
62    Result += "sspreq ";
63  if (Attrs & Attribute::NoRedZone)
64    Result += "noredzone ";
65  if (Attrs & Attribute::NoImplicitFloat)
66    Result += "noimplicitfloat ";
67  if (Attrs & Attribute::Naked)
68    Result += "naked ";
69  if (Attrs & Attribute::Alignment) {
70    Result += "align ";
71    Result += utostr(Attribute::getAlignmentFromAttrs(Attrs));
72    Result += " ";
73  }
74  // Trim the trailing space.
75  assert(!Result.empty() && "Unknown attribute!");
76  Result.erase(Result.end()-1);
77  return Result;
78}
79
80Attributes Attribute::typeIncompatible(const Type *Ty) {
81  Attributes Incompatible = None;
82
83  if (!Ty->isInteger())
84    // Attributes that only apply to integers.
85    Incompatible |= SExt | ZExt;
86
87  if (!isa<PointerType>(Ty))
88    // Attributes that only apply to pointers.
89    Incompatible |= ByVal | Nest | NoAlias | StructRet | NoCapture;
90
91  return Incompatible;
92}
93
94//===----------------------------------------------------------------------===//
95// AttributeListImpl Definition
96//===----------------------------------------------------------------------===//
97
98namespace llvm {
99class AttributeListImpl : public FoldingSetNode {
100  unsigned RefCount;
101
102  // AttributesList is uniqued, these should not be publicly available.
103  void operator=(const AttributeListImpl &); // Do not implement
104  AttributeListImpl(const AttributeListImpl &); // Do not implement
105  ~AttributeListImpl();                        // Private implementation
106public:
107  SmallVector<AttributeWithIndex, 4> Attrs;
108
109  AttributeListImpl(const AttributeWithIndex *Attr, unsigned NumAttrs)
110    : Attrs(Attr, Attr+NumAttrs) {
111    RefCount = 0;
112  }
113
114  void AddRef() { ++RefCount; }
115  void DropRef() { if (--RefCount == 0) delete this; }
116
117  void Profile(FoldingSetNodeID &ID) const {
118    Profile(ID, Attrs.data(), Attrs.size());
119  }
120  static void Profile(FoldingSetNodeID &ID, const AttributeWithIndex *Attr,
121                      unsigned NumAttrs) {
122    for (unsigned i = 0; i != NumAttrs; ++i)
123      ID.AddInteger(uint64_t(Attr[i].Attrs) << 32 | unsigned(Attr[i].Index));
124  }
125};
126}
127
128static ManagedStatic<sys::SmartMutex<true> > ALMutex;
129static ManagedStatic<FoldingSet<AttributeListImpl> > AttributesLists;
130
131AttributeListImpl::~AttributeListImpl() {
132  sys::SmartScopedLock<true> Lock(*ALMutex);
133  AttributesLists->RemoveNode(this);
134}
135
136
137AttrListPtr AttrListPtr::get(const AttributeWithIndex *Attrs, unsigned NumAttrs) {
138  // If there are no attributes then return a null AttributesList pointer.
139  if (NumAttrs == 0)
140    return AttrListPtr();
141
142#ifndef NDEBUG
143  for (unsigned i = 0; i != NumAttrs; ++i) {
144    assert(Attrs[i].Attrs != Attribute::None &&
145           "Pointless attribute!");
146    assert((!i || Attrs[i-1].Index < Attrs[i].Index) &&
147           "Misordered AttributesList!");
148  }
149#endif
150
151  // Otherwise, build a key to look up the existing attributes.
152  FoldingSetNodeID ID;
153  AttributeListImpl::Profile(ID, Attrs, NumAttrs);
154  void *InsertPos;
155
156  sys::SmartScopedLock<true> Lock(*ALMutex);
157
158  AttributeListImpl *PAL =
159    AttributesLists->FindNodeOrInsertPos(ID, InsertPos);
160
161  // If we didn't find any existing attributes of the same shape then
162  // create a new one and insert it.
163  if (!PAL) {
164    PAL = new AttributeListImpl(Attrs, NumAttrs);
165    AttributesLists->InsertNode(PAL, InsertPos);
166  }
167
168  // Return the AttributesList that we found or created.
169  return AttrListPtr(PAL);
170}
171
172
173//===----------------------------------------------------------------------===//
174// AttrListPtr Method Implementations
175//===----------------------------------------------------------------------===//
176
177AttrListPtr::AttrListPtr(AttributeListImpl *LI) : AttrList(LI) {
178  if (LI) LI->AddRef();
179}
180
181AttrListPtr::AttrListPtr(const AttrListPtr &P) : AttrList(P.AttrList) {
182  if (AttrList) AttrList->AddRef();
183}
184
185const AttrListPtr &AttrListPtr::operator=(const AttrListPtr &RHS) {
186  if (AttrList == RHS.AttrList) return *this;
187  if (AttrList) AttrList->DropRef();
188  AttrList = RHS.AttrList;
189  if (AttrList) AttrList->AddRef();
190  return *this;
191}
192
193AttrListPtr::~AttrListPtr() {
194  if (AttrList) AttrList->DropRef();
195}
196
197/// getNumSlots - Return the number of slots used in this attribute list.
198/// This is the number of arguments that have an attribute set on them
199/// (including the function itself).
200unsigned AttrListPtr::getNumSlots() const {
201  return AttrList ? AttrList->Attrs.size() : 0;
202}
203
204/// getSlot - Return the AttributeWithIndex at the specified slot.  This
205/// holds a number plus a set of attributes.
206const AttributeWithIndex &AttrListPtr::getSlot(unsigned Slot) const {
207  assert(AttrList && Slot < AttrList->Attrs.size() && "Slot # out of range!");
208  return AttrList->Attrs[Slot];
209}
210
211
212/// getAttributes - The attributes for the specified index are
213/// returned.  Attributes for the result are denoted with Idx = 0.
214/// Function notes are denoted with idx = ~0.
215Attributes AttrListPtr::getAttributes(unsigned Idx) const {
216  if (AttrList == 0) return Attribute::None;
217
218  const SmallVector<AttributeWithIndex, 4> &Attrs = AttrList->Attrs;
219  for (unsigned i = 0, e = Attrs.size(); i != e && Attrs[i].Index <= Idx; ++i)
220    if (Attrs[i].Index == Idx)
221      return Attrs[i].Attrs;
222  return Attribute::None;
223}
224
225/// hasAttrSomewhere - Return true if the specified attribute is set for at
226/// least one parameter or for the return value.
227bool AttrListPtr::hasAttrSomewhere(Attributes Attr) const {
228  if (AttrList == 0) return false;
229
230  const SmallVector<AttributeWithIndex, 4> &Attrs = AttrList->Attrs;
231  for (unsigned i = 0, e = Attrs.size(); i != e; ++i)
232    if (Attrs[i].Attrs & Attr)
233      return true;
234  return false;
235}
236
237
238AttrListPtr AttrListPtr::addAttr(unsigned Idx, Attributes Attrs) const {
239  Attributes OldAttrs = getAttributes(Idx);
240#ifndef NDEBUG
241  // FIXME it is not obvious how this should work for alignment.
242  // For now, say we can't change a known alignment.
243  Attributes OldAlign = OldAttrs & Attribute::Alignment;
244  Attributes NewAlign = Attrs & Attribute::Alignment;
245  assert((!OldAlign || !NewAlign || OldAlign == NewAlign) &&
246         "Attempt to change alignment!");
247#endif
248
249  Attributes NewAttrs = OldAttrs | Attrs;
250  if (NewAttrs == OldAttrs)
251    return *this;
252
253  SmallVector<AttributeWithIndex, 8> NewAttrList;
254  if (AttrList == 0)
255    NewAttrList.push_back(AttributeWithIndex::get(Idx, Attrs));
256  else {
257    const SmallVector<AttributeWithIndex, 4> &OldAttrList = AttrList->Attrs;
258    unsigned i = 0, e = OldAttrList.size();
259    // Copy attributes for arguments before this one.
260    for (; i != e && OldAttrList[i].Index < Idx; ++i)
261      NewAttrList.push_back(OldAttrList[i]);
262
263    // If there are attributes already at this index, merge them in.
264    if (i != e && OldAttrList[i].Index == Idx) {
265      Attrs |= OldAttrList[i].Attrs;
266      ++i;
267    }
268
269    NewAttrList.push_back(AttributeWithIndex::get(Idx, Attrs));
270
271    // Copy attributes for arguments after this one.
272    NewAttrList.insert(NewAttrList.end(),
273                       OldAttrList.begin()+i, OldAttrList.end());
274  }
275
276  return get(NewAttrList.data(), NewAttrList.size());
277}
278
279AttrListPtr AttrListPtr::removeAttr(unsigned Idx, Attributes Attrs) const {
280#ifndef NDEBUG
281  // FIXME it is not obvious how this should work for alignment.
282  // For now, say we can't pass in alignment, which no current use does.
283  assert(!(Attrs & Attribute::Alignment) && "Attempt to exclude alignment!");
284#endif
285  if (AttrList == 0) return AttrListPtr();
286
287  Attributes OldAttrs = getAttributes(Idx);
288  Attributes NewAttrs = OldAttrs & ~Attrs;
289  if (NewAttrs == OldAttrs)
290    return *this;
291
292  SmallVector<AttributeWithIndex, 8> NewAttrList;
293  const SmallVector<AttributeWithIndex, 4> &OldAttrList = AttrList->Attrs;
294  unsigned i = 0, e = OldAttrList.size();
295
296  // Copy attributes for arguments before this one.
297  for (; i != e && OldAttrList[i].Index < Idx; ++i)
298    NewAttrList.push_back(OldAttrList[i]);
299
300  // If there are attributes already at this index, merge them in.
301  assert(OldAttrList[i].Index == Idx && "Attribute isn't set?");
302  Attrs = OldAttrList[i].Attrs & ~Attrs;
303  ++i;
304  if (Attrs)  // If any attributes left for this parameter, add them.
305    NewAttrList.push_back(AttributeWithIndex::get(Idx, Attrs));
306
307  // Copy attributes for arguments after this one.
308  NewAttrList.insert(NewAttrList.end(),
309                     OldAttrList.begin()+i, OldAttrList.end());
310
311  return get(NewAttrList.data(), NewAttrList.size());
312}
313
314void AttrListPtr::dump() const {
315  cerr << "PAL[ ";
316  for (unsigned i = 0; i < getNumSlots(); ++i) {
317    const AttributeWithIndex &PAWI = getSlot(i);
318    cerr << "{" << PAWI.Index << "," << PAWI.Attrs << "} ";
319  }
320
321  cerr << "]\n";
322}
323