Mangle.cpp revision 651f13cea278ec967336033dd032faef0e9fc2ec 
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 StdOrFastCC {
53  SOF_OTHER,
54  SOF_FAST,
55  SOF_STD
56};
57
58static bool isExternC(const NamedDecl *ND) {
59  if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND))
60    return FD->isExternC();
61  return cast<VarDecl>(ND)->isExternC();
62}
63
64static StdOrFastCC getStdOrFastCallMangling(const ASTContext &Context,
65                                            const NamedDecl *ND) {
66  const TargetInfo &TI = Context.getTargetInfo();
67  const llvm::Triple &Triple = TI.getTriple();
68  if (!Triple.isOSWindows() || Triple.getArch() != llvm::Triple::x86)
69    return SOF_OTHER;
70
71  if (Context.getLangOpts().CPlusPlus && !isExternC(ND) &&
72      TI.getCXXABI() == TargetCXXABI::Microsoft)
73    return SOF_OTHER;
74
75  const FunctionDecl *FD = dyn_cast<FunctionDecl>(ND);
76  if (!FD)
77    return SOF_OTHER;
78  QualType T = FD->getType();
79
80  const FunctionType *FT = T->castAs<FunctionType>();
81
82  CallingConv CC = FT->getCallConv();
83  switch (CC) {
84  default:
85    return SOF_OTHER;
86  case CC_X86FastCall:
87    return SOF_FAST;
88  case CC_X86StdCall:
89    return SOF_STD;
90  }
91}
92
93bool MangleContext::shouldMangleDeclName(const NamedDecl *D) {
94  const ASTContext &ASTContext = getASTContext();
95
96  StdOrFastCC CC = getStdOrFastCallMangling(ASTContext, D);
97  if (CC != SOF_OTHER)
98    return true;
99
100  // In C, functions with no attributes never need to be mangled. Fastpath them.
101  if (!getASTContext().getLangOpts().CPlusPlus && !D->hasAttrs())
102    return false;
103
104  // Any decl can be declared with __asm("foo") on it, and this takes precedence
105  // over all other naming in the .o file.
106  if (D->hasAttr<AsmLabelAttr>())
107    return true;
108
109  return shouldMangleCXXName(D);
110}
111
112void MangleContext::mangleName(const NamedDecl *D, raw_ostream &Out) {
113  // Any decl can be declared with __asm("foo") on it, and this takes precedence
114  // over all other naming in the .o file.
115  if (const AsmLabelAttr *ALA = D->getAttr<AsmLabelAttr>()) {
116    // If we have an asm name, then we use it as the mangling.
117
118    // Adding the prefix can cause problems when one file has a "foo" and
119    // another has a "\01foo". That is known to happen on ELF with the
120    // tricks normally used for producing aliases (PR9177). Fortunately the
121    // llvm mangler on ELF is a nop, so we can just avoid adding the \01
122    // marker.  We also avoid adding the marker if this is an alias for an
123    // LLVM intrinsic.
124    StringRef UserLabelPrefix =
125        getASTContext().getTargetInfo().getUserLabelPrefix();
126    if (!UserLabelPrefix.empty() && !ALA->getLabel().startswith("llvm."))
127      Out << '\01'; // LLVM IR Marker for __asm("foo")
128
129    Out << ALA->getLabel();
130    return;
131  }
132
133  const ASTContext &ASTContext = getASTContext();
134  StdOrFastCC CC = getStdOrFastCallMangling(ASTContext, D);
135  bool MCXX = shouldMangleCXXName(D);
136  const TargetInfo &TI = Context.getTargetInfo();
137  if (CC == SOF_OTHER || (MCXX && TI.getCXXABI() == TargetCXXABI::Microsoft)) {
138    mangleCXXName(D, Out);
139    return;
140  }
141
142  Out << '\01';
143  if (CC == SOF_STD)
144    Out << '_';
145  else
146    Out << '@';
147
148  if (!MCXX)
149    Out << D->getIdentifier()->getName();
150  else
151    mangleCXXName(D, Out);
152
153  const FunctionDecl *FD = cast<FunctionDecl>(D);
154  const FunctionType *FT = FD->getType()->castAs<FunctionType>();
155  const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT);
156  Out << '@';
157  if (!Proto) {
158    Out << '0';
159    return;
160  }
161  assert(!Proto->isVariadic());
162  unsigned ArgWords = 0;
163  if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD))
164    if (!MD->isStatic())
165      ++ArgWords;
166  for (const auto &AT : Proto->param_types())
167    // Size should be aligned to DWORD boundary
168    ArgWords += llvm::RoundUpToAlignment(ASTContext.getTypeSize(AT), 32) / 32;
169  Out << 4 * ArgWords;
170}
171
172void MangleContext::mangleGlobalBlock(const BlockDecl *BD,
173                                      const NamedDecl *ID,
174                                      raw_ostream &Out) {
175  unsigned discriminator = getBlockId(BD, false);
176  if (ID) {
177    if (shouldMangleDeclName(ID))
178      mangleName(ID, Out);
179    else {
180      Out << ID->getIdentifier()->getName();
181    }
182  }
183  if (discriminator == 0)
184    Out << "_block_invoke";
185  else
186    Out << "_block_invoke_" << discriminator+1;
187}
188
189void MangleContext::mangleCtorBlock(const CXXConstructorDecl *CD,
190                                    CXXCtorType CT, const BlockDecl *BD,
191                                    raw_ostream &ResStream) {
192  SmallString<64> Buffer;
193  llvm::raw_svector_ostream Out(Buffer);
194  mangleCXXCtor(CD, CT, Out);
195  Out.flush();
196  mangleFunctionBlock(*this, Buffer, BD, ResStream);
197}
198
199void MangleContext::mangleDtorBlock(const CXXDestructorDecl *DD,
200                                    CXXDtorType DT, const BlockDecl *BD,
201                                    raw_ostream &ResStream) {
202  SmallString<64> Buffer;
203  llvm::raw_svector_ostream Out(Buffer);
204  mangleCXXDtor(DD, DT, Out);
205  Out.flush();
206  mangleFunctionBlock(*this, Buffer, BD, ResStream);
207}
208
209void MangleContext::mangleBlock(const DeclContext *DC, const BlockDecl *BD,
210                                raw_ostream &Out) {
211  assert(!isa<CXXConstructorDecl>(DC) && !isa<CXXDestructorDecl>(DC));
212
213  SmallString<64> Buffer;
214  llvm::raw_svector_ostream Stream(Buffer);
215  if (const ObjCMethodDecl *Method = dyn_cast<ObjCMethodDecl>(DC)) {
216    mangleObjCMethodName(Method, Stream);
217  } else {
218    const NamedDecl *ND = cast<NamedDecl>(DC);
219    if (!shouldMangleDeclName(ND) && ND->getIdentifier())
220      Stream << ND->getIdentifier()->getName();
221    else {
222      // FIXME: We were doing a mangleUnqualifiedName() before, but that's
223      // a private member of a class that will soon itself be private to the
224      // Itanium C++ ABI object. What should we do now? Right now, I'm just
225      // calling the mangleName() method on the MangleContext; is there a
226      // better way?
227      mangleName(ND, Stream);
228    }
229  }
230  Stream.flush();
231  mangleFunctionBlock(*this, Buffer, BD, Out);
232}
233
234void MangleContext::mangleObjCMethodName(const ObjCMethodDecl *MD,
235                                         raw_ostream &Out) {
236  SmallString<64> Name;
237  llvm::raw_svector_ostream OS(Name);
238
239  const ObjCContainerDecl *CD =
240  dyn_cast<ObjCContainerDecl>(MD->getDeclContext());
241  assert (CD && "Missing container decl in GetNameForMethod");
242  OS << (MD->isInstanceMethod() ? '-' : '+') << '[' << CD->getName();
243  if (const ObjCCategoryImplDecl *CID = dyn_cast<ObjCCategoryImplDecl>(CD))
244    OS << '(' << *CID << ')';
245  OS << ' ';
246  MD->getSelector().print(OS);
247  OS << ']';
248
249  Out << OS.str().size() << OS.str();
250}
251