Attributes.cpp revision cfa6ec92e61a1ab040c2b79db5de3a39df732ff6 
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/ManagedStatic.h"
21#include "llvm/Support/raw_ostream.h"
22using namespace llvm;
23
24//===----------------------------------------------------------------------===//
25// Attribute Function Definitions
26//===----------------------------------------------------------------------===//
27
28std::string Attribute::getAsString(Attributes Attrs) {
29  std::string Result;
30  if (Attrs & Attribute::ZExt)
31    Result += "zeroext ";
32  if (Attrs & Attribute::SExt)
33    Result += "signext ";
34  if (Attrs & Attribute::NoReturn)
35    Result += "noreturn ";
36  if (Attrs & Attribute::NoUnwind)
37    Result += "nounwind ";
38  if (Attrs & Attribute::InReg)
39    Result += "inreg ";
40  if (Attrs & Attribute::NoAlias)
41    Result += "noalias ";
42  if (Attrs & Attribute::NoCapture)
43    Result += "nocapture ";
44  if (Attrs & Attribute::StructRet)
45    Result += "sret ";
46  if (Attrs & Attribute::ByVal)
47    Result += "byval ";
48  if (Attrs & Attribute::Nest)
49    Result += "nest ";
50  if (Attrs & Attribute::ReadNone)
51    Result += "readnone ";
52  if (Attrs & Attribute::ReadOnly)
53    Result += "readonly ";
54  if (Attrs & Attribute::OptimizeForSize)
55    Result += "optsize ";
56  if (Attrs & Attribute::NoInline)
57    Result += "noinline ";
58  if (Attrs & Attribute::AlwaysInline)
59    Result += "alwaysinline ";
60  if (Attrs & Attribute::StackProtect)
61    Result += "ssp ";
62  if (Attrs & Attribute::StackProtectReq)
63    Result += "sspreq ";
64  if (Attrs & Attribute::NoRedZone)
65    Result += "noredzone ";
66  if (Attrs & Attribute::NoImplicitFloat)
67    Result += "noimplicitfloat ";
68  if (Attrs & Attribute::Naked)
69    Result += "naked ";
70  if (Attrs & Attribute::Alignment) {
71    Result += "align ";
72    Result += utostr(Attribute::getAlignmentFromAttrs(Attrs));
73    Result += " ";
74  }
75  // Trim the trailing space.
76  assert(!Result.empty() && "Unknown attribute!");
77  Result.erase(Result.end()-1);
78  return Result;
79}
80
81Attributes Attribute::typeIncompatible(const Type *Ty) {
82  Attributes Incompatible = None;
83
84  if (!Ty->isInteger())
85    // Attributes that only apply to integers.
86    Incompatible |= SExt | ZExt;
87
88  if (!isa<PointerType>(Ty))
89    // Attributes that only apply to pointers.
90    Incompatible |= ByVal | Nest | NoAlias | StructRet | NoCapture;
91
92  return Incompatible;
93}
94
95//===----------------------------------------------------------------------===//
96// AttributeListImpl Definition
97//===----------------------------------------------------------------------===//
98
99namespace llvm {
100class AttributeListImpl : public FoldingSetNode {
101  sys::cas_flag RefCount;
102
103  // AttributesList is uniqued, these should not be publicly available.
104  void operator=(const AttributeListImpl &); // Do not implement
105  AttributeListImpl(const AttributeListImpl &); // Do not implement
106  ~AttributeListImpl();                        // Private implementation
107public:
108  SmallVector<AttributeWithIndex, 4> Attrs;
109
110  AttributeListImpl(const AttributeWithIndex *Attr, unsigned NumAttrs)
111    : Attrs(Attr, Attr+NumAttrs) {
112    RefCount = 0;
113  }
114
115  void AddRef() { sys::AtomicIncrement(&RefCount); }
116  void DropRef() {
117    sys::cas_flag old = sys::AtomicDecrement(&RefCount);
118    if (old == 0) delete this;
119  }
120
121  void Profile(FoldingSetNodeID &ID) const {
122    Profile(ID, Attrs.data(), Attrs.size());
123  }
124  static void Profile(FoldingSetNodeID &ID, const AttributeWithIndex *Attr,
125                      unsigned NumAttrs) {
126    for (unsigned i = 0; i != NumAttrs; ++i)
127      ID.AddInteger(uint64_t(Attr[i].Attrs) << 32 | unsigned(Attr[i].Index));
128  }
129};
130}
131
132static ManagedStatic<sys::SmartMutex<true> > ALMutex;
133static ManagedStatic<FoldingSet<AttributeListImpl> > AttributesLists;
134
135AttributeListImpl::~AttributeListImpl() {
136  sys::SmartScopedLock<true> Lock(*ALMutex);
137  AttributesLists->RemoveNode(this);
138}
139
140
141AttrListPtr AttrListPtr::get(const AttributeWithIndex *Attrs, unsigned NumAttrs) {
142  // If there are no attributes then return a null AttributesList pointer.
143  if (NumAttrs == 0)
144    return AttrListPtr();
145
146#ifndef NDEBUG
147  for (unsigned i = 0; i != NumAttrs; ++i) {
148    assert(Attrs[i].Attrs != Attribute::None &&
149           "Pointless attribute!");
150    assert((!i || Attrs[i-1].Index < Attrs[i].Index) &&
151           "Misordered AttributesList!");
152  }
153#endif
154
155  // Otherwise, build a key to look up the existing attributes.
156  FoldingSetNodeID ID;
157  AttributeListImpl::Profile(ID, Attrs, NumAttrs);
158  void *InsertPos;
159
160  sys::SmartScopedLock<true> Lock(*ALMutex);
161
162  AttributeListImpl *PAL =
163    AttributesLists->FindNodeOrInsertPos(ID, InsertPos);
164
165  // If we didn't find any existing attributes of the same shape then
166  // create a new one and insert it.
167  if (!PAL) {
168    PAL = new AttributeListImpl(Attrs, NumAttrs);
169    AttributesLists->InsertNode(PAL, InsertPos);
170  }
171
172  // Return the AttributesList that we found or created.
173  return AttrListPtr(PAL);
174}
175
176
177//===----------------------------------------------------------------------===//
178// AttrListPtr Method Implementations
179//===----------------------------------------------------------------------===//
180
181AttrListPtr::AttrListPtr(AttributeListImpl *LI) : AttrList(LI) {
182  if (LI) LI->AddRef();
183}
184
185AttrListPtr::AttrListPtr(const AttrListPtr &P) : AttrList(P.AttrList) {
186  if (AttrList) AttrList->AddRef();
187}
188
189const AttrListPtr &AttrListPtr::operator=(const AttrListPtr &RHS) {
190  if (AttrList == RHS.AttrList) return *this;
191  if (AttrList) AttrList->DropRef();
192  AttrList = RHS.AttrList;
193  if (AttrList) AttrList->AddRef();
194  return *this;
195}
196
197AttrListPtr::~AttrListPtr() {
198  if (AttrList) AttrList->DropRef();
199}
200
201/// getNumSlots - Return the number of slots used in this attribute list.
202/// This is the number of arguments that have an attribute set on them
203/// (including the function itself).
204unsigned AttrListPtr::getNumSlots() const {
205  return AttrList ? AttrList->Attrs.size() : 0;
206}
207
208/// getSlot - Return the AttributeWithIndex at the specified slot.  This
209/// holds a number plus a set of attributes.
210const AttributeWithIndex &AttrListPtr::getSlot(unsigned Slot) const {
211  assert(AttrList && Slot < AttrList->Attrs.size() && "Slot # out of range!");
212  return AttrList->Attrs[Slot];
213}
214
215
216/// getAttributes - The attributes for the specified index are
217/// returned.  Attributes for the result are denoted with Idx = 0.
218/// Function notes are denoted with idx = ~0.
219Attributes AttrListPtr::getAttributes(unsigned Idx) const {
220  if (AttrList == 0) return Attribute::None;
221
222  const SmallVector<AttributeWithIndex, 4> &Attrs = AttrList->Attrs;
223  for (unsigned i = 0, e = Attrs.size(); i != e && Attrs[i].Index <= Idx; ++i)
224    if (Attrs[i].Index == Idx)
225      return Attrs[i].Attrs;
226  return Attribute::None;
227}
228
229/// hasAttrSomewhere - Return true if the specified attribute is set for at
230/// least one parameter or for the return value.
231bool AttrListPtr::hasAttrSomewhere(Attributes Attr) const {
232  if (AttrList == 0) return false;
233
234  const SmallVector<AttributeWithIndex, 4> &Attrs = AttrList->Attrs;
235  for (unsigned i = 0, e = Attrs.size(); i != e; ++i)
236    if (Attrs[i].Attrs & Attr)
237      return true;
238  return false;
239}
240
241
242AttrListPtr AttrListPtr::addAttr(unsigned Idx, Attributes Attrs) const {
243  Attributes OldAttrs = getAttributes(Idx);
244#ifndef NDEBUG
245  // FIXME it is not obvious how this should work for alignment.
246  // For now, say we can't change a known alignment.
247  Attributes OldAlign = OldAttrs & Attribute::Alignment;
248  Attributes NewAlign = Attrs & Attribute::Alignment;
249  assert((!OldAlign || !NewAlign || OldAlign == NewAlign) &&
250         "Attempt to change alignment!");
251#endif
252
253  Attributes NewAttrs = OldAttrs | Attrs;
254  if (NewAttrs == OldAttrs)
255    return *this;
256
257  SmallVector<AttributeWithIndex, 8> NewAttrList;
258  if (AttrList == 0)
259    NewAttrList.push_back(AttributeWithIndex::get(Idx, Attrs));
260  else {
261    const SmallVector<AttributeWithIndex, 4> &OldAttrList = AttrList->Attrs;
262    unsigned i = 0, e = OldAttrList.size();
263    // Copy attributes for arguments before this one.
264    for (; i != e && OldAttrList[i].Index < Idx; ++i)
265      NewAttrList.push_back(OldAttrList[i]);
266
267    // If there are attributes already at this index, merge them in.
268    if (i != e && OldAttrList[i].Index == Idx) {
269      Attrs |= OldAttrList[i].Attrs;
270      ++i;
271    }
272
273    NewAttrList.push_back(AttributeWithIndex::get(Idx, Attrs));
274
275    // Copy attributes for arguments after this one.
276    NewAttrList.insert(NewAttrList.end(),
277                       OldAttrList.begin()+i, OldAttrList.end());
278  }
279
280  return get(NewAttrList.data(), NewAttrList.size());
281}
282
283AttrListPtr AttrListPtr::removeAttr(unsigned Idx, Attributes Attrs) const {
284#ifndef NDEBUG
285  // FIXME it is not obvious how this should work for alignment.
286  // For now, say we can't pass in alignment, which no current use does.
287  assert(!(Attrs & Attribute::Alignment) && "Attempt to exclude alignment!");
288#endif
289  if (AttrList == 0) return AttrListPtr();
290
291  Attributes OldAttrs = getAttributes(Idx);
292  Attributes NewAttrs = OldAttrs & ~Attrs;
293  if (NewAttrs == OldAttrs)
294    return *this;
295
296  SmallVector<AttributeWithIndex, 8> NewAttrList;
297  const SmallVector<AttributeWithIndex, 4> &OldAttrList = AttrList->Attrs;
298  unsigned i = 0, e = OldAttrList.size();
299
300  // Copy attributes for arguments before this one.
301  for (; i != e && OldAttrList[i].Index < Idx; ++i)
302    NewAttrList.push_back(OldAttrList[i]);
303
304  // If there are attributes already at this index, merge them in.
305  assert(OldAttrList[i].Index == Idx && "Attribute isn't set?");
306  Attrs = OldAttrList[i].Attrs & ~Attrs;
307  ++i;
308  if (Attrs)  // If any attributes left for this parameter, add them.
309    NewAttrList.push_back(AttributeWithIndex::get(Idx, Attrs));
310
311  // Copy attributes for arguments after this one.
312  NewAttrList.insert(NewAttrList.end(),
313                     OldAttrList.begin()+i, OldAttrList.end());
314
315  return get(NewAttrList.data(), NewAttrList.size());
316}
317
318void AttrListPtr::dump() const {
319  errs() << "PAL[ ";
320  for (unsigned i = 0; i < getNumSlots(); ++i) {
321    const AttributeWithIndex &PAWI = getSlot(i);
322    errs() << "{" << PAWI.Index << "," << PAWI.Attrs << "} ";
323  }
324
325  errs() << "]\n";
326}
327