Mangle.cpp revision 321369 
1//===--- Mangle.cpp - Mangle C++ Names --------------------------*- C++ -*-===//
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// Implements generic name mangling support for blocks and Objective-C.
11//
12//===----------------------------------------------------------------------===//
13#include "clang/AST/Attr.h"
14#include "clang/AST/ASTContext.h"
15#include "clang/AST/Decl.h"
16#include "clang/AST/DeclCXX.h"
17#include "clang/AST/DeclObjC.h"
18#include "clang/AST/DeclTemplate.h"
19#include "clang/AST/ExprCXX.h"
20#include "clang/AST/Mangle.h"
21#include "clang/Basic/ABI.h"
22#include "clang/Basic/SourceManager.h"
23#include "clang/Basic/TargetInfo.h"
24#include "llvm/ADT/StringExtras.h"
25#include "llvm/Support/ErrorHandling.h"
26#include "llvm/Support/raw_ostream.h"
27
28#define MANGLE_CHECKER 0
29
30#if MANGLE_CHECKER
31#include <cxxabi.h>
32#endif
33
34using namespace clang;
35
36// FIXME: For blocks we currently mimic GCC's mangling scheme, which leaves
37// much to be desired. Come up with a better mangling scheme.
38
39static void mangleFunctionBlock(MangleContext &Context,
40                                StringRef Outer,
41                                const BlockDecl *BD,
42                                raw_ostream &Out) {
43  unsigned discriminator = Context.getBlockId(BD, true);
44  if (discriminator == 0)
45    Out << "__" << Outer << "_block_invoke";
46  else
47    Out << "__" << Outer << "_block_invoke_" << discriminator+1;
48}
49
50void MangleContext::anchor() { }
51
52enum CCMangling {
53  CCM_Other,
54  CCM_Fast,
55  CCM_RegCall,
56  CCM_Vector,
57  CCM_Std
58};
59
60static bool isExternC(const NamedDecl *ND) {
61  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
62    return FD->isExternC();
63  return cast<VarDecl>(ND)->isExternC();
64}
65
66static CCMangling getCallingConvMangling(const ASTContext &Context,
67                                         const NamedDecl *ND) {
68  const TargetInfo &TI = Context.getTargetInfo();
69  const llvm::Triple &Triple = TI.getTriple();
70  if (!Triple.isOSWindows() ||
71      !(Triple.getArch() == llvm::Triple::x86 ||
72        Triple.getArch() == llvm::Triple::x86_64))
73    return CCM_Other;
74
75  if (Context.getLangOpts().CPlusPlus && !isExternC(ND) &&
76      TI.getCXXABI() == TargetCXXABI::Microsoft)
77    return CCM_Other;
78
79  const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND);
80  if (!FD)
81    return CCM_Other;
82  QualType T = FD->getType();
83
84  const FunctionType *FT = T->castAs<FunctionType>();
85
86  CallingConv CC = FT->getCallConv();
87  switch (CC) {
88  default:
89    return CCM_Other;
90  case CC_X86FastCall:
91    return CCM_Fast;
92  case CC_X86StdCall:
93    return CCM_Std;
94  case CC_X86VectorCall:
95    return CCM_Vector;
96  }
97}
98
99bool MangleContext::shouldMangleDeclName(const NamedDecl *D) {
100  const ASTContext &ASTContext = getASTContext();
101
102  CCMangling CC = getCallingConvMangling(ASTContext, D);
103  if (CC != CCM_Other)
104    return true;
105
106  // In C, functions with no attributes never need to be mangled. Fastpath them.
107  if (!getASTContext().getLangOpts().CPlusPlus && !D->hasAttrs())
108    return false;
109
110  // Any decl can be declared with __asm("foo") on it, and this takes precedence
111  // over all other naming in the .o file.
112  if (D->hasAttr<AsmLabelAttr>())
113    return true;
114
115  return shouldMangleCXXName(D);
116}
117
118void MangleContext::mangleName(const NamedDecl *D, raw_ostream &Out) {
119  // Any decl can be declared with __asm("foo") on it, and this takes precedence
120  // over all other naming in the .o file.
121  if (const AsmLabelAttr *ALA = D->getAttr<AsmLabelAttr>()) {
122    // If we have an asm name, then we use it as the mangling.
123
124    // Adding the prefix can cause problems when one file has a "foo" and
125    // another has a "\01foo". That is known to happen on ELF with the
126    // tricks normally used for producing aliases (PR9177). Fortunately the
127    // llvm mangler on ELF is a nop, so we can just avoid adding the \01
128    // marker.  We also avoid adding the marker if this is an alias for an
129    // LLVM intrinsic.
130    char GlobalPrefix =
131        getASTContext().getTargetInfo().getDataLayout().getGlobalPrefix();
132    if (GlobalPrefix && !ALA->getLabel().startswith("llvm."))
133      Out << '\01'; // LLVM IR Marker for __asm("foo")
134
135    Out << ALA->getLabel();
136    return;
137  }
138
139  const ASTContext &ASTContext = getASTContext();
140  CCMangling CC = getCallingConvMangling(ASTContext, D);
141  bool MCXX = shouldMangleCXXName(D);
142  const TargetInfo &TI = Context.getTargetInfo();
143  if (CC == CCM_Other || (MCXX && TI.getCXXABI() == TargetCXXABI::Microsoft)) {
144    if (const ObjCMethodDecl *OMD = dyn_cast<ObjCMethodDecl>(D))
145      mangleObjCMethodName(OMD, Out);
146    else
147      mangleCXXName(D, Out);
148    return;
149  }
150
151  Out << '\01';
152  if (CC == CCM_Std)
153    Out << '_';
154  else if (CC == CCM_Fast)
155    Out << '@';
156  else if (CC == CCM_RegCall)
157    Out << "__regcall3__";
158
159  if (!MCXX)
160    Out << D->getIdentifier()->getName();
161  else if (const ObjCMethodDecl *OMD = dyn_cast<ObjCMethodDecl>(D))
162    mangleObjCMethodName(OMD, Out);
163  else
164    mangleCXXName(D, Out);
165
166  const FunctionDecl *FD = cast<FunctionDecl>(D);
167  const FunctionType *FT = FD->getType()->castAs<FunctionType>();
168  const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT);
169  if (CC == CCM_Vector)
170    Out << '@';
171  Out << '@';
172  if (!Proto) {
173    Out << '0';
174    return;
175  }
176  assert(!Proto->isVariadic());
177  unsigned ArgWords = 0;
178  if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD))
179    if (!MD->isStatic())
180      ++ArgWords;
181  for (const auto &AT : Proto->param_types())
182    // Size should be aligned to pointer size.
183    ArgWords +=
184        llvm::alignTo(ASTContext.getTypeSize(AT), TI.getPointerWidth(0)) /
185        TI.getPointerWidth(0);
186  Out << ((TI.getPointerWidth(0) / 8) * ArgWords);
187}
188
189void MangleContext::mangleGlobalBlock(const BlockDecl *BD,
190                                      const NamedDecl *ID,
191                                      raw_ostream &Out) {
192  unsigned discriminator = getBlockId(BD, false);
193  if (ID) {
194    if (shouldMangleDeclName(ID))
195      mangleName(ID, Out);
196    else {
197      Out << ID->getIdentifier()->getName();
198    }
199  }
200  if (discriminator == 0)
201    Out << "_block_invoke";
202  else
203    Out << "_block_invoke_" << discriminator+1;
204}
205
206void MangleContext::mangleCtorBlock(const CXXConstructorDecl *CD,
207                                    CXXCtorType CT, const BlockDecl *BD,
208                                    raw_ostream &ResStream) {
209  SmallString<64> Buffer;
210  llvm::raw_svector_ostream Out(Buffer);
211  mangleCXXCtor(CD, CT, Out);
212  mangleFunctionBlock(*this, Buffer, BD, ResStream);
213}
214
215void MangleContext::mangleDtorBlock(const CXXDestructorDecl *DD,
216                                    CXXDtorType DT, const BlockDecl *BD,
217                                    raw_ostream &ResStream) {
218  SmallString<64> Buffer;
219  llvm::raw_svector_ostream Out(Buffer);
220  mangleCXXDtor(DD, DT, Out);
221  mangleFunctionBlock(*this, Buffer, BD, ResStream);
222}
223
224void MangleContext::mangleBlock(const DeclContext *DC, const BlockDecl *BD,
225                                raw_ostream &Out) {
226  assert(!isa<CXXConstructorDecl>(DC) && !isa<CXXDestructorDecl>(DC));
227
228  SmallString<64> Buffer;
229  llvm::raw_svector_ostream Stream(Buffer);
230  if (const ObjCMethodDecl *Method = dyn_cast<ObjCMethodDecl>(DC)) {
231    mangleObjCMethodName(Method, Stream);
232  } else {
233    assert((isa<NamedDecl>(DC) || isa<BlockDecl>(DC)) &&
234           "expected a NamedDecl or BlockDecl");
235    if (isa<BlockDecl>(DC))
236      for (; DC && isa<BlockDecl>(DC); DC = DC->getParent())
237        (void) getBlockId(cast<BlockDecl>(DC), true);
238    assert((isa<TranslationUnitDecl>(DC) || isa<NamedDecl>(DC)) &&
239           "expected a TranslationUnitDecl or a NamedDecl");
240    if (const auto *CD = dyn_cast<CXXConstructorDecl>(DC))
241      mangleCtorBlock(CD, /*CT*/ Ctor_Complete, BD, Out);
242    else if (const auto *DD = dyn_cast<CXXDestructorDecl>(DC))
243      mangleDtorBlock(DD, /*DT*/ Dtor_Complete, BD, Out);
244    else if (auto ND = dyn_cast<NamedDecl>(DC)) {
245      if (!shouldMangleDeclName(ND) && ND->getIdentifier())
246        Stream << ND->getIdentifier()->getName();
247      else {
248        // FIXME: We were doing a mangleUnqualifiedName() before, but that's
249        // a private member of a class that will soon itself be private to the
250        // Itanium C++ ABI object. What should we do now? Right now, I'm just
251        // calling the mangleName() method on the MangleContext; is there a
252        // better way?
253        mangleName(ND, Stream);
254      }
255    }
256  }
257  mangleFunctionBlock(*this, Buffer, BD, Out);
258}
259
260void MangleContext::mangleObjCMethodNameWithoutSize(const ObjCMethodDecl *MD,
261                                                    raw_ostream &OS) {
262  const ObjCContainerDecl *CD =
263  dyn_cast<ObjCContainerDecl>(MD->getDeclContext());
264  assert (CD && "Missing container decl in GetNameForMethod");
265  OS << (MD->isInstanceMethod() ? '-' : '+') << '[';
266  if (const ObjCCategoryImplDecl *CID = dyn_cast<ObjCCategoryImplDecl>(CD)) {
267    OS << CID->getClassInterface()->getName();
268    OS << '(' << *CID << ')';
269  } else {
270    OS << CD->getName();
271  }
272  OS << ' ';
273  MD->getSelector().print(OS);
274  OS << ']';
275}
276
277void MangleContext::mangleObjCMethodName(const ObjCMethodDecl *MD,
278                                         raw_ostream &Out) {
279  SmallString<64> Name;
280  llvm::raw_svector_ostream OS(Name);
281
282  mangleObjCMethodNameWithoutSize(MD, OS);
283  Out << OS.str().size() << OS.str();
284}
285