Mangle.cpp revision 309124 
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_Vector,
56  CCM_Std
57};
58
59static bool isExternC(const NamedDecl *ND) {
60  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
61    return FD->isExternC();
62  return cast<VarDecl>(ND)->isExternC();
63}
64
65static CCMangling getCallingConvMangling(const ASTContext &Context,
66                                         const NamedDecl *ND) {
67  const TargetInfo &TI = Context.getTargetInfo();
68  const llvm::Triple &Triple = TI.getTriple();
69  if (!Triple.isOSWindows() ||
70      !(Triple.getArch() == llvm::Triple::x86 ||
71        Triple.getArch() == llvm::Triple::x86_64))
72    return CCM_Other;
73
74  if (Context.getLangOpts().CPlusPlus && !isExternC(ND) &&
75      TI.getCXXABI() == TargetCXXABI::Microsoft)
76    return CCM_Other;
77
78  const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND);
79  if (!FD)
80    return CCM_Other;
81  QualType T = FD->getType();
82
83  const FunctionType *FT = T->castAs<FunctionType>();
84
85  CallingConv CC = FT->getCallConv();
86  switch (CC) {
87  default:
88    return CCM_Other;
89  case CC_X86FastCall:
90    return CCM_Fast;
91  case CC_X86StdCall:
92    return CCM_Std;
93  case CC_X86VectorCall:
94    return CCM_Vector;
95  }
96}
97
98bool MangleContext::shouldMangleDeclName(const NamedDecl *D) {
99  const ASTContext &ASTContext = getASTContext();
100
101  CCMangling CC = getCallingConvMangling(ASTContext, D);
102  if (CC != CCM_Other)
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
156  if (!MCXX)
157    Out << D->getIdentifier()->getName();
158  else if (const ObjCMethodDecl *OMD = dyn_cast<ObjCMethodDecl>(D))
159    mangleObjCMethodName(OMD, Out);
160  else
161    mangleCXXName(D, Out);
162
163  const FunctionDecl *FD = cast<FunctionDecl>(D);
164  const FunctionType *FT = FD->getType()->castAs<FunctionType>();
165  const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT);
166  if (CC == CCM_Vector)
167    Out << '@';
168  Out << '@';
169  if (!Proto) {
170    Out << '0';
171    return;
172  }
173  assert(!Proto->isVariadic());
174  unsigned ArgWords = 0;
175  if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD))
176    if (!MD->isStatic())
177      ++ArgWords;
178  for (const auto &AT : Proto->param_types())
179    // Size should be aligned to pointer size.
180    ArgWords +=
181        llvm::alignTo(ASTContext.getTypeSize(AT), TI.getPointerWidth(0)) /
182        TI.getPointerWidth(0);
183  Out << ((TI.getPointerWidth(0) / 8) * ArgWords);
184}
185
186void MangleContext::mangleGlobalBlock(const BlockDecl *BD,
187                                      const NamedDecl *ID,
188                                      raw_ostream &Out) {
189  unsigned discriminator = getBlockId(BD, false);
190  if (ID) {
191    if (shouldMangleDeclName(ID))
192      mangleName(ID, Out);
193    else {
194      Out << ID->getIdentifier()->getName();
195    }
196  }
197  if (discriminator == 0)
198    Out << "_block_invoke";
199  else
200    Out << "_block_invoke_" << discriminator+1;
201}
202
203void MangleContext::mangleCtorBlock(const CXXConstructorDecl *CD,
204                                    CXXCtorType CT, const BlockDecl *BD,
205                                    raw_ostream &ResStream) {
206  SmallString<64> Buffer;
207  llvm::raw_svector_ostream Out(Buffer);
208  mangleCXXCtor(CD, CT, Out);
209  mangleFunctionBlock(*this, Buffer, BD, ResStream);
210}
211
212void MangleContext::mangleDtorBlock(const CXXDestructorDecl *DD,
213                                    CXXDtorType DT, const BlockDecl *BD,
214                                    raw_ostream &ResStream) {
215  SmallString<64> Buffer;
216  llvm::raw_svector_ostream Out(Buffer);
217  mangleCXXDtor(DD, DT, Out);
218  mangleFunctionBlock(*this, Buffer, BD, ResStream);
219}
220
221void MangleContext::mangleBlock(const DeclContext *DC, const BlockDecl *BD,
222                                raw_ostream &Out) {
223  assert(!isa<CXXConstructorDecl>(DC) && !isa<CXXDestructorDecl>(DC));
224
225  SmallString<64> Buffer;
226  llvm::raw_svector_ostream Stream(Buffer);
227  if (const ObjCMethodDecl *Method = dyn_cast<ObjCMethodDecl>(DC)) {
228    mangleObjCMethodName(Method, Stream);
229  } else {
230    assert((isa<NamedDecl>(DC) || isa<BlockDecl>(DC)) &&
231           "expected a NamedDecl or BlockDecl");
232    if (isa<BlockDecl>(DC))
233      for (; DC && isa<BlockDecl>(DC); DC = DC->getParent())
234        (void) getBlockId(cast<BlockDecl>(DC), true);
235    assert((isa<TranslationUnitDecl>(DC) || isa<NamedDecl>(DC)) &&
236           "expected a TranslationUnitDecl or a NamedDecl");
237    if (const auto *CD = dyn_cast<CXXConstructorDecl>(DC))
238      mangleCtorBlock(CD, /*CT*/ Ctor_Complete, BD, Out);
239    else if (const auto *DD = dyn_cast<CXXDestructorDecl>(DC))
240      mangleDtorBlock(DD, /*DT*/ Dtor_Complete, BD, Out);
241    else if (auto ND = dyn_cast<NamedDecl>(DC)) {
242      if (!shouldMangleDeclName(ND) && ND->getIdentifier())
243        Stream << ND->getIdentifier()->getName();
244      else {
245        // FIXME: We were doing a mangleUnqualifiedName() before, but that's
246        // a private member of a class that will soon itself be private to the
247        // Itanium C++ ABI object. What should we do now? Right now, I'm just
248        // calling the mangleName() method on the MangleContext; is there a
249        // better way?
250        mangleName(ND, Stream);
251      }
252    }
253  }
254  mangleFunctionBlock(*this, Buffer, BD, Out);
255}
256
257void MangleContext::mangleObjCMethodNameWithoutSize(const ObjCMethodDecl *MD,
258                                                    raw_ostream &OS) {
259  const ObjCContainerDecl *CD =
260  dyn_cast<ObjCContainerDecl>(MD->getDeclContext());
261  assert (CD && "Missing container decl in GetNameForMethod");
262  OS << (MD->isInstanceMethod() ? '-' : '+') << '[' << CD->getName();
263  if (const ObjCCategoryImplDecl *CID = dyn_cast<ObjCCategoryImplDecl>(CD))
264    OS << '(' << *CID << ')';
265  OS << ' ';
266  MD->getSelector().print(OS);
267  OS << ']';
268}
269
270void MangleContext::mangleObjCMethodName(const ObjCMethodDecl *MD,
271                                         raw_ostream &Out) {
272  SmallString<64> Name;
273  llvm::raw_svector_ostream OS(Name);
274
275  mangleObjCMethodNameWithoutSize(MD, OS);
276  Out << OS.str().size() << OS.str();
277}
278