Mangle.cpp revision 344779 
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
28using namespace clang;
29
30// FIXME: For blocks we currently mimic GCC's mangling scheme, which leaves
31// much to be desired. Come up with a better mangling scheme.
32
33static void mangleFunctionBlock(MangleContext &Context,
34                                StringRef Outer,
35                                const BlockDecl *BD,
36                                raw_ostream &Out) {
37  unsigned discriminator = Context.getBlockId(BD, true);
38  if (discriminator == 0)
39    Out << "__" << Outer << "_block_invoke";
40  else
41    Out << "__" << Outer << "_block_invoke_" << discriminator+1;
42}
43
44void MangleContext::anchor() { }
45
46enum CCMangling {
47  CCM_Other,
48  CCM_Fast,
49  CCM_RegCall,
50  CCM_Vector,
51  CCM_Std
52};
53
54static bool isExternC(const NamedDecl *ND) {
55  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
56    return FD->isExternC();
57  return cast<VarDecl>(ND)->isExternC();
58}
59
60static CCMangling getCallingConvMangling(const ASTContext &Context,
61                                         const NamedDecl *ND) {
62  const TargetInfo &TI = Context.getTargetInfo();
63  const llvm::Triple &Triple = TI.getTriple();
64  if (!Triple.isOSWindows() ||
65      !(Triple.getArch() == llvm::Triple::x86 ||
66        Triple.getArch() == llvm::Triple::x86_64))
67    return CCM_Other;
68
69  if (Context.getLangOpts().CPlusPlus && !isExternC(ND) &&
70      TI.getCXXABI() == TargetCXXABI::Microsoft)
71    return CCM_Other;
72
73  const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND);
74  if (!FD)
75    return CCM_Other;
76  QualType T = FD->getType();
77
78  const FunctionType *FT = T->castAs<FunctionType>();
79
80  CallingConv CC = FT->getCallConv();
81  switch (CC) {
82  default:
83    return CCM_Other;
84  case CC_X86FastCall:
85    return CCM_Fast;
86  case CC_X86StdCall:
87    return CCM_Std;
88  case CC_X86VectorCall:
89    return CCM_Vector;
90  }
91}
92
93bool MangleContext::shouldMangleDeclName(const NamedDecl *D) {
94  const ASTContext &ASTContext = getASTContext();
95
96  CCMangling CC = getCallingConvMangling(ASTContext, D);
97  if (CC != CCM_Other)
98    return true;
99
100  // If the declaration has an owning module for linkage purposes that needs to
101  // be mangled, we must mangle its name.
102  if (!D->hasExternalFormalLinkage() && D->getOwningModuleForLinkage())
103    return true;
104
105  // In C, functions with no attributes never need to be mangled. Fastpath them.
106  if (!getASTContext().getLangOpts().CPlusPlus && !D->hasAttrs())
107    return false;
108
109  // Any decl can be declared with __asm("foo") on it, and this takes precedence
110  // over all other naming in the .o file.
111  if (D->hasAttr<AsmLabelAttr>())
112    return true;
113
114  return shouldMangleCXXName(D);
115}
116
117void MangleContext::mangleName(const NamedDecl *D, raw_ostream &Out) {
118  // Any decl can be declared with __asm("foo") on it, and this takes precedence
119  // over all other naming in the .o file.
120  if (const AsmLabelAttr *ALA = D->getAttr<AsmLabelAttr>()) {
121    // If we have an asm name, then we use it as the mangling.
122
123    // Adding the prefix can cause problems when one file has a "foo" and
124    // another has a "\01foo". That is known to happen on ELF with the
125    // tricks normally used for producing aliases (PR9177). Fortunately the
126    // llvm mangler on ELF is a nop, so we can just avoid adding the \01
127    // marker.  We also avoid adding the marker if this is an alias for an
128    // LLVM intrinsic.
129    char GlobalPrefix =
130        getASTContext().getTargetInfo().getDataLayout().getGlobalPrefix();
131    if (GlobalPrefix && !ALA->getLabel().startswith("llvm."))
132      Out << '\01'; // LLVM IR Marker for __asm("foo")
133
134    Out << ALA->getLabel();
135    return;
136  }
137
138  const ASTContext &ASTContext = getASTContext();
139  CCMangling CC = getCallingConvMangling(ASTContext, D);
140  bool MCXX = shouldMangleCXXName(D);
141  const TargetInfo &TI = Context.getTargetInfo();
142  if (CC == CCM_Other || (MCXX && TI.getCXXABI() == TargetCXXABI::Microsoft)) {
143    if (const ObjCMethodDecl *OMD = dyn_cast<ObjCMethodDecl>(D))
144      mangleObjCMethodName(OMD, Out);
145    else
146      mangleCXXName(D, Out);
147    return;
148  }
149
150  Out << '\01';
151  if (CC == CCM_Std)
152    Out << '_';
153  else if (CC == CCM_Fast)
154    Out << '@';
155  else if (CC == CCM_RegCall)
156    Out << "__regcall3__";
157
158  if (!MCXX)
159    Out << D->getIdentifier()->getName();
160  else if (const ObjCMethodDecl *OMD = dyn_cast<ObjCMethodDecl>(D))
161    mangleObjCMethodName(OMD, Out);
162  else
163    mangleCXXName(D, Out);
164
165  const FunctionDecl *FD = cast<FunctionDecl>(D);
166  const FunctionType *FT = FD->getType()->castAs<FunctionType>();
167  const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT);
168  if (CC == CCM_Vector)
169    Out << '@';
170  Out << '@';
171  if (!Proto) {
172    Out << '0';
173    return;
174  }
175  assert(!Proto->isVariadic());
176  unsigned ArgWords = 0;
177  if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD))
178    if (!MD->isStatic())
179      ++ArgWords;
180  for (const auto &AT : Proto->param_types())
181    // Size should be aligned to pointer size.
182    ArgWords +=
183        llvm::alignTo(ASTContext.getTypeSize(AT), TI.getPointerWidth(0)) /
184        TI.getPointerWidth(0);
185  Out << ((TI.getPointerWidth(0) / 8) * ArgWords);
186}
187
188void MangleContext::mangleGlobalBlock(const BlockDecl *BD,
189                                      const NamedDecl *ID,
190                                      raw_ostream &Out) {
191  unsigned discriminator = getBlockId(BD, false);
192  if (ID) {
193    if (shouldMangleDeclName(ID))
194      mangleName(ID, Out);
195    else {
196      Out << ID->getIdentifier()->getName();
197    }
198  }
199  if (discriminator == 0)
200    Out << "_block_invoke";
201  else
202    Out << "_block_invoke_" << discriminator+1;
203}
204
205void MangleContext::mangleCtorBlock(const CXXConstructorDecl *CD,
206                                    CXXCtorType CT, const BlockDecl *BD,
207                                    raw_ostream &ResStream) {
208  SmallString<64> Buffer;
209  llvm::raw_svector_ostream Out(Buffer);
210  mangleCXXCtor(CD, CT, Out);
211  mangleFunctionBlock(*this, Buffer, BD, ResStream);
212}
213
214void MangleContext::mangleDtorBlock(const CXXDestructorDecl *DD,
215                                    CXXDtorType DT, const BlockDecl *BD,
216                                    raw_ostream &ResStream) {
217  SmallString<64> Buffer;
218  llvm::raw_svector_ostream Out(Buffer);
219  mangleCXXDtor(DD, DT, Out);
220  mangleFunctionBlock(*this, Buffer, BD, ResStream);
221}
222
223void MangleContext::mangleBlock(const DeclContext *DC, const BlockDecl *BD,
224                                raw_ostream &Out) {
225  assert(!isa<CXXConstructorDecl>(DC) && !isa<CXXDestructorDecl>(DC));
226
227  SmallString<64> Buffer;
228  llvm::raw_svector_ostream Stream(Buffer);
229  if (const ObjCMethodDecl *Method = dyn_cast<ObjCMethodDecl>(DC)) {
230    mangleObjCMethodName(Method, Stream);
231  } else {
232    assert((isa<NamedDecl>(DC) || isa<BlockDecl>(DC)) &&
233           "expected a NamedDecl or BlockDecl");
234    if (isa<BlockDecl>(DC))
235      for (; DC && isa<BlockDecl>(DC); DC = DC->getParent())
236        (void) getBlockId(cast<BlockDecl>(DC), true);
237    assert((isa<TranslationUnitDecl>(DC) || isa<NamedDecl>(DC)) &&
238           "expected a TranslationUnitDecl or a NamedDecl");
239    if (const auto *CD = dyn_cast<CXXConstructorDecl>(DC))
240      mangleCtorBlock(CD, /*CT*/ Ctor_Complete, BD, Out);
241    else if (const auto *DD = dyn_cast<CXXDestructorDecl>(DC))
242      mangleDtorBlock(DD, /*DT*/ Dtor_Complete, BD, Out);
243    else if (auto ND = dyn_cast<NamedDecl>(DC)) {
244      if (!shouldMangleDeclName(ND) && ND->getIdentifier())
245        Stream << ND->getIdentifier()->getName();
246      else {
247        // FIXME: We were doing a mangleUnqualifiedName() before, but that's
248        // a private member of a class that will soon itself be private to the
249        // Itanium C++ ABI object. What should we do now? Right now, I'm just
250        // calling the mangleName() method on the MangleContext; is there a
251        // better way?
252        mangleName(ND, Stream);
253      }
254    }
255  }
256  mangleFunctionBlock(*this, Buffer, BD, Out);
257}
258
259void MangleContext::mangleObjCMethodNameWithoutSize(const ObjCMethodDecl *MD,
260                                                    raw_ostream &OS) {
261  const ObjCContainerDecl *CD =
262  dyn_cast<ObjCContainerDecl>(MD->getDeclContext());
263  assert (CD && "Missing container decl in GetNameForMethod");
264  OS << (MD->isInstanceMethod() ? '-' : '+') << '[';
265  if (const ObjCCategoryImplDecl *CID = dyn_cast<ObjCCategoryImplDecl>(CD)) {
266    OS << CID->getClassInterface()->getName();
267    OS << '(' << *CID << ')';
268  } else {
269    OS << CD->getName();
270  }
271  OS << ' ';
272  MD->getSelector().print(OS);
273  OS << ']';
274}
275
276void MangleContext::mangleObjCMethodName(const ObjCMethodDecl *MD,
277                                         raw_ostream &Out) {
278  SmallString<64> Name;
279  llvm::raw_svector_ostream OS(Name);
280
281  mangleObjCMethodNameWithoutSize(MD, OS);
282  Out << OS.str().size() << OS.str();
283}
284