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
34 using 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
mangleFunctionBlock(MangleContext & Context,StringRef Outer,const BlockDecl * BD,raw_ostream & Out)39 static 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
anchor()50 void MangleContext::anchor() { }
51
52 enum CCMangling {
53 CCM_Other,
54 CCM_Fast,
55 CCM_Vector,
56 CCM_Std
57 };
58
isExternC(const NamedDecl * ND)59 static 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
getCallingConvMangling(const ASTContext & Context,const NamedDecl * ND)65 static 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
shouldMangleDeclName(const NamedDecl * D)98 bool 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
mangleName(const NamedDecl * D,raw_ostream & Out)117 void 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 StringRef UserLabelPrefix =
130 getASTContext().getTargetInfo().getUserLabelPrefix();
131 if (!UserLabelPrefix.empty() && !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 += llvm::RoundUpToAlignment(ASTContext.getTypeSize(AT),
181 TI.getPointerWidth(0)) /
182 TI.getPointerWidth(0);
183 Out << ((TI.getPointerWidth(0) / 8) * ArgWords);
184 }
185
mangleGlobalBlock(const BlockDecl * BD,const NamedDecl * ID,raw_ostream & Out)186 void 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
mangleCtorBlock(const CXXConstructorDecl * CD,CXXCtorType CT,const BlockDecl * BD,raw_ostream & ResStream)203 void 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 Out.flush();
210 mangleFunctionBlock(*this, Buffer, BD, ResStream);
211 }
212
mangleDtorBlock(const CXXDestructorDecl * DD,CXXDtorType DT,const BlockDecl * BD,raw_ostream & ResStream)213 void MangleContext::mangleDtorBlock(const CXXDestructorDecl *DD,
214 CXXDtorType DT, const BlockDecl *BD,
215 raw_ostream &ResStream) {
216 SmallString<64> Buffer;
217 llvm::raw_svector_ostream Out(Buffer);
218 mangleCXXDtor(DD, DT, Out);
219 Out.flush();
220 mangleFunctionBlock(*this, Buffer, BD, ResStream);
221 }
222
mangleBlock(const DeclContext * DC,const BlockDecl * BD,raw_ostream & Out)223 void 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 Stream.flush();
257 mangleFunctionBlock(*this, Buffer, BD, Out);
258 }
259
mangleObjCMethodName(const ObjCMethodDecl * MD,raw_ostream & Out)260 void MangleContext::mangleObjCMethodName(const ObjCMethodDecl *MD,
261 raw_ostream &Out) {
262 SmallString<64> Name;
263 llvm::raw_svector_ostream OS(Name);
264
265 const ObjCContainerDecl *CD =
266 dyn_cast<ObjCContainerDecl>(MD->getDeclContext());
267 assert (CD && "Missing container decl in GetNameForMethod");
268 OS << (MD->isInstanceMethod() ? '-' : '+') << '[' << CD->getName();
269 if (const ObjCCategoryImplDecl *CID = dyn_cast<ObjCCategoryImplDecl>(CD))
270 OS << '(' << *CID << ')';
271 OS << ' ';
272 MD->getSelector().print(OS);
273 OS << ']';
274
275 Out << OS.str().size() << OS.str();
276 }
277