Attributes.cpp revision 25456ef74ca7ac9bf46451f28d995f785e2596de 
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/Atomic.h"
19#include "llvm/Support/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::UWTable)
40    Result += "uwtable ";
41  if (Attrs & Attribute::ReturnsTwice)
42    Result += "returns_twice ";
43  if (Attrs & Attribute::InReg)
44    Result += "inreg ";
45  if (Attrs & Attribute::NoAlias)
46    Result += "noalias ";
47  if (Attrs & Attribute::NoCapture)
48    Result += "nocapture ";
49  if (Attrs & Attribute::StructRet)
50    Result += "sret ";
51  if (Attrs & Attribute::ByVal)
52    Result += "byval ";
53  if (Attrs & Attribute::Nest)
54    Result += "nest ";
55  if (Attrs & Attribute::ReadNone)
56    Result += "readnone ";
57  if (Attrs & Attribute::ReadOnly)
58    Result += "readonly ";
59  if (Attrs & Attribute::OptimizeForSize)
60    Result += "optsize ";
61  if (Attrs & Attribute::NoInline)
62    Result += "noinline ";
63  if (Attrs & Attribute::InlineHint)
64    Result += "inlinehint ";
65  if (Attrs & Attribute::AlwaysInline)
66    Result += "alwaysinline ";
67  if (Attrs & Attribute::StackProtect)
68    Result += "ssp ";
69  if (Attrs & Attribute::StackProtectReq)
70    Result += "sspreq ";
71  if (Attrs & Attribute::NoRedZone)
72    Result += "noredzone ";
73  if (Attrs & Attribute::NoImplicitFloat)
74    Result += "noimplicitfloat ";
75  if (Attrs & Attribute::Naked)
76    Result += "naked ";
77  if (Attrs & Attribute::NonLazyBind)
78    Result += "nonlazybind ";
79  if (Attrs & Attribute::StackAlignment) {
80    Result += "alignstack(";
81    Result += utostr(Attribute::getStackAlignmentFromAttrs(Attrs));
82    Result += ") ";
83  }
84  if (Attrs & Attribute::Alignment) {
85    Result += "align ";
86    Result += utostr(Attribute::getAlignmentFromAttrs(Attrs));
87    Result += " ";
88  }
89  // Trim the trailing space.
90  assert(!Result.empty() && "Unknown attribute!");
91  Result.erase(Result.end()-1);
92  return Result;
93}
94
95Attributes Attribute::typeIncompatible(Type *Ty) {
96  Attributes Incompatible = None;
97
98  if (!Ty->isIntegerTy())
99    // Attributes that only apply to integers.
100    Incompatible |= SExt | ZExt;
101
102  if (!Ty->isPointerTy())
103    // Attributes that only apply to pointers.
104    Incompatible |= ByVal | Nest | NoAlias | StructRet | NoCapture;
105
106  return Incompatible;
107}
108
109//===----------------------------------------------------------------------===//
110// AttributeListImpl Definition
111//===----------------------------------------------------------------------===//
112
113namespace llvm {
114  class AttributeListImpl;
115}
116
117static ManagedStatic<FoldingSet<AttributeListImpl> > AttributesLists;
118
119namespace llvm {
120static ManagedStatic<sys::SmartMutex<true> > ALMutex;
121
122class AttributeListImpl : public FoldingSetNode {
123  sys::cas_flag RefCount;
124
125  // AttributesList is uniqued, these should not be publicly available.
126  void operator=(const AttributeListImpl &); // Do not implement
127  AttributeListImpl(const AttributeListImpl &); // Do not implement
128  ~AttributeListImpl();                        // Private implementation
129public:
130  SmallVector<AttributeWithIndex, 4> Attrs;
131
132  AttributeListImpl(const AttributeWithIndex *Attr, unsigned NumAttrs)
133    : Attrs(Attr, Attr+NumAttrs) {
134    RefCount = 0;
135  }
136
137  void AddRef() {
138    sys::SmartScopedLock<true> Lock(*ALMutex);
139    ++RefCount;
140  }
141  void DropRef() {
142    sys::SmartScopedLock<true> Lock(*ALMutex);
143    if (!AttributesLists.isConstructed())
144      return;
145    sys::cas_flag new_val = --RefCount;
146    if (new_val == 0)
147      delete this;
148  }
149
150  void Profile(FoldingSetNodeID &ID) const {
151    Profile(ID, Attrs.data(), Attrs.size());
152  }
153  static void Profile(FoldingSetNodeID &ID, const AttributeWithIndex *Attr,
154                      unsigned NumAttrs) {
155    for (unsigned i = 0; i != NumAttrs; ++i)
156      ID.AddInteger(uint64_t(Attr[i].Attrs) << 32 | unsigned(Attr[i].Index));
157  }
158};
159}
160
161AttributeListImpl::~AttributeListImpl() {
162  // NOTE: Lock must be acquired by caller.
163  AttributesLists->RemoveNode(this);
164}
165
166
167AttrListPtr AttrListPtr::get(const AttributeWithIndex *Attrs, unsigned NumAttrs) {
168  // If there are no attributes then return a null AttributesList pointer.
169  if (NumAttrs == 0)
170    return AttrListPtr();
171
172#ifndef NDEBUG
173  for (unsigned i = 0; i != NumAttrs; ++i) {
174    assert(Attrs[i].Attrs != Attribute::None &&
175           "Pointless attribute!");
176    assert((!i || Attrs[i-1].Index < Attrs[i].Index) &&
177           "Misordered AttributesList!");
178  }
179#endif
180
181  // Otherwise, build a key to look up the existing attributes.
182  FoldingSetNodeID ID;
183  AttributeListImpl::Profile(ID, Attrs, NumAttrs);
184  void *InsertPos;
185
186  sys::SmartScopedLock<true> Lock(*ALMutex);
187
188  AttributeListImpl *PAL =
189    AttributesLists->FindNodeOrInsertPos(ID, InsertPos);
190
191  // If we didn't find any existing attributes of the same shape then
192  // create a new one and insert it.
193  if (!PAL) {
194    PAL = new AttributeListImpl(Attrs, NumAttrs);
195    AttributesLists->InsertNode(PAL, InsertPos);
196  }
197
198  // Return the AttributesList that we found or created.
199  return AttrListPtr(PAL);
200}
201
202
203//===----------------------------------------------------------------------===//
204// AttrListPtr Method Implementations
205//===----------------------------------------------------------------------===//
206
207AttrListPtr::AttrListPtr(AttributeListImpl *LI) : AttrList(LI) {
208  if (LI) LI->AddRef();
209}
210
211AttrListPtr::AttrListPtr(const AttrListPtr &P) : AttrList(P.AttrList) {
212  if (AttrList) AttrList->AddRef();
213}
214
215const AttrListPtr &AttrListPtr::operator=(const AttrListPtr &RHS) {
216  sys::SmartScopedLock<true> Lock(*ALMutex);
217  if (AttrList == RHS.AttrList) return *this;
218  if (AttrList) AttrList->DropRef();
219  AttrList = RHS.AttrList;
220  if (AttrList) AttrList->AddRef();
221  return *this;
222}
223
224AttrListPtr::~AttrListPtr() {
225  if (AttrList) AttrList->DropRef();
226}
227
228/// getNumSlots - Return the number of slots used in this attribute list.
229/// This is the number of arguments that have an attribute set on them
230/// (including the function itself).
231unsigned AttrListPtr::getNumSlots() const {
232  return AttrList ? AttrList->Attrs.size() : 0;
233}
234
235/// getSlot - Return the AttributeWithIndex at the specified slot.  This
236/// holds a number plus a set of attributes.
237const AttributeWithIndex &AttrListPtr::getSlot(unsigned Slot) const {
238  assert(AttrList && Slot < AttrList->Attrs.size() && "Slot # out of range!");
239  return AttrList->Attrs[Slot];
240}
241
242
243/// getAttributes - The attributes for the specified index are
244/// returned.  Attributes for the result are denoted with Idx = 0.
245/// Function notes are denoted with idx = ~0.
246Attributes AttrListPtr::getAttributes(unsigned Idx) const {
247  if (AttrList == 0) return Attribute::None;
248
249  const SmallVector<AttributeWithIndex, 4> &Attrs = AttrList->Attrs;
250  for (unsigned i = 0, e = Attrs.size(); i != e && Attrs[i].Index <= Idx; ++i)
251    if (Attrs[i].Index == Idx)
252      return Attrs[i].Attrs;
253  return Attribute::None;
254}
255
256/// hasAttrSomewhere - Return true if the specified attribute is set for at
257/// least one parameter or for the return value.
258bool AttrListPtr::hasAttrSomewhere(Attributes Attr) const {
259  if (AttrList == 0) return false;
260
261  const SmallVector<AttributeWithIndex, 4> &Attrs = AttrList->Attrs;
262  for (unsigned i = 0, e = Attrs.size(); i != e; ++i)
263    if (Attrs[i].Attrs & Attr)
264      return true;
265  return false;
266}
267
268
269AttrListPtr AttrListPtr::addAttr(unsigned Idx, Attributes Attrs) const {
270  Attributes OldAttrs = getAttributes(Idx);
271#ifndef NDEBUG
272  // FIXME it is not obvious how this should work for alignment.
273  // For now, say we can't change a known alignment.
274  Attributes OldAlign = OldAttrs & Attribute::Alignment;
275  Attributes NewAlign = Attrs & Attribute::Alignment;
276  assert((!OldAlign || !NewAlign || OldAlign == NewAlign) &&
277         "Attempt to change alignment!");
278#endif
279
280  Attributes NewAttrs = OldAttrs | Attrs;
281  if (NewAttrs == OldAttrs)
282    return *this;
283
284  SmallVector<AttributeWithIndex, 8> NewAttrList;
285  if (AttrList == 0)
286    NewAttrList.push_back(AttributeWithIndex::get(Idx, Attrs));
287  else {
288    const SmallVector<AttributeWithIndex, 4> &OldAttrList = AttrList->Attrs;
289    unsigned i = 0, e = OldAttrList.size();
290    // Copy attributes for arguments before this one.
291    for (; i != e && OldAttrList[i].Index < Idx; ++i)
292      NewAttrList.push_back(OldAttrList[i]);
293
294    // If there are attributes already at this index, merge them in.
295    if (i != e && OldAttrList[i].Index == Idx) {
296      Attrs |= OldAttrList[i].Attrs;
297      ++i;
298    }
299
300    NewAttrList.push_back(AttributeWithIndex::get(Idx, Attrs));
301
302    // Copy attributes for arguments after this one.
303    NewAttrList.insert(NewAttrList.end(),
304                       OldAttrList.begin()+i, OldAttrList.end());
305  }
306
307  return get(NewAttrList.data(), NewAttrList.size());
308}
309
310AttrListPtr AttrListPtr::removeAttr(unsigned Idx, Attributes Attrs) const {
311#ifndef NDEBUG
312  // FIXME it is not obvious how this should work for alignment.
313  // For now, say we can't pass in alignment, which no current use does.
314  assert(!(Attrs & Attribute::Alignment) && "Attempt to exclude alignment!");
315#endif
316  if (AttrList == 0) return AttrListPtr();
317
318  Attributes OldAttrs = getAttributes(Idx);
319  Attributes NewAttrs = OldAttrs & ~Attrs;
320  if (NewAttrs == OldAttrs)
321    return *this;
322
323  SmallVector<AttributeWithIndex, 8> NewAttrList;
324  const SmallVector<AttributeWithIndex, 4> &OldAttrList = AttrList->Attrs;
325  unsigned i = 0, e = OldAttrList.size();
326
327  // Copy attributes for arguments before this one.
328  for (; i != e && OldAttrList[i].Index < Idx; ++i)
329    NewAttrList.push_back(OldAttrList[i]);
330
331  // If there are attributes already at this index, merge them in.
332  assert(OldAttrList[i].Index == Idx && "Attribute isn't set?");
333  Attrs = OldAttrList[i].Attrs & ~Attrs;
334  ++i;
335  if (Attrs)  // If any attributes left for this parameter, add them.
336    NewAttrList.push_back(AttributeWithIndex::get(Idx, Attrs));
337
338  // Copy attributes for arguments after this one.
339  NewAttrList.insert(NewAttrList.end(),
340                     OldAttrList.begin()+i, OldAttrList.end());
341
342  return get(NewAttrList.data(), NewAttrList.size());
343}
344
345void AttrListPtr::dump() const {
346  dbgs() << "PAL[ ";
347  for (unsigned i = 0; i < getNumSlots(); ++i) {
348    const AttributeWithIndex &PAWI = getSlot(i);
349    dbgs() << "{" << PAWI.Index << "," << PAWI.Attrs << "} ";
350  }
351
352  dbgs() << "]\n";
353}
354