Sema.cpp revision b6c8c8bd8d362c8a6cdb767415b0d21e62b77eb2 
1//===--- Sema.cpp - AST Builder and Semantic Analysis Implementation ------===//
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// This file implements the actions class which performs semantic analysis and
11// builds an AST out of a parse stream.
12//
13//===----------------------------------------------------------------------===//
14
15#include "Sema.h"
16#include "clang/AST/ASTConsumer.h"
17#include "clang/AST/ASTContext.h"
18#include "clang/AST/DeclObjC.h"
19#include "clang/AST/Expr.h"
20#include "clang/Lex/Preprocessor.h"
21using namespace clang;
22
23/// ConvertQualTypeToStringFn - This function is used to pretty print the
24/// specified QualType as a string in diagnostics.
25static void ConvertArgToStringFn(Diagnostic::ArgumentKind Kind, intptr_t Val,
26                                 const char *Modifier, unsigned ModLen,
27                                 const char *Argument, unsigned ArgLen,
28                                 llvm::SmallVectorImpl<char> &Output,
29                                 void *Cookie) {
30  ASTContext &Context = *static_cast<ASTContext*>(Cookie);
31
32  std::string S;
33  if (Kind == Diagnostic::ak_qualtype) {
34    assert(ModLen == 0 && ArgLen == 0 &&
35           "Invalid modifier for QualType argument");
36
37    QualType Ty(QualType::getFromOpaquePtr(reinterpret_cast<void*>(Val)));
38
39    // FIXME: Playing with std::string is really slow.
40    S = Ty.getAsString();
41
42    // If this is a sugared type (like a typedef, typeof, etc), then unwrap one
43    // level of the sugar so that the type is more obvious to the user.
44    QualType DesugaredTy = Ty->getDesugaredType(true);
45    DesugaredTy.setCVRQualifiers(DesugaredTy.getCVRQualifiers() |
46                                 Ty.getCVRQualifiers());
47
48    if (Ty != DesugaredTy &&
49        // If the desugared type is a vector type, we don't want to expand it,
50        // it will turn into an attribute mess. People want their "vec4".
51        !isa<VectorType>(DesugaredTy) &&
52
53        // Don't desugar magic Objective-C types.
54        Ty.getUnqualifiedType() != Context.getObjCIdType() &&
55        Ty.getUnqualifiedType() != Context.getObjCSelType() &&
56        Ty.getUnqualifiedType() != Context.getObjCProtoType() &&
57        Ty.getUnqualifiedType() != Context.getObjCClassType() &&
58
59        // Not va_list.
60        Ty.getUnqualifiedType() != Context.getBuiltinVaListType()) {
61      S = "'"+S+"' (aka '";
62      S += DesugaredTy.getAsString();
63      S += "')";
64      Output.append(S.begin(), S.end());
65      return;
66    }
67
68  } else if (Kind == Diagnostic::ak_declarationname) {
69
70    DeclarationName N = DeclarationName::getFromOpaqueInteger(Val);
71    S = N.getAsString();
72
73    if (ModLen == 9 && !memcmp(Modifier, "objcclass", 9) && ArgLen == 0)
74      S = '+' + S;
75    else if (ModLen == 12 && !memcmp(Modifier, "objcinstance", 12) && ArgLen==0)
76      S = '-' + S;
77    else
78      assert(ModLen == 0 && ArgLen == 0 &&
79             "Invalid modifier for DeclarationName argument");
80  } else {
81    assert(Kind == Diagnostic::ak_nameddecl);
82    if (ModLen == 1 && Modifier[0] == 'q' && ArgLen == 0)
83      S = reinterpret_cast<NamedDecl*>(Val)->getQualifiedNameAsString();
84    else {
85      assert(ModLen == 0 && ArgLen == 0 &&
86           "Invalid modifier for NamedDecl* argument");
87      S = reinterpret_cast<NamedDecl*>(Val)->getNameAsString();
88    }
89  }
90
91  Output.push_back('\'');
92  Output.append(S.begin(), S.end());
93  Output.push_back('\'');
94}
95
96
97static inline RecordDecl *CreateStructDecl(ASTContext &C, const char *Name) {
98  if (C.getLangOptions().CPlusPlus)
99    return CXXRecordDecl::Create(C, TagDecl::TK_struct,
100                                 C.getTranslationUnitDecl(),
101                                 SourceLocation(), &C.Idents.get(Name));
102
103  return RecordDecl::Create(C, TagDecl::TK_struct,
104                            C.getTranslationUnitDecl(),
105                            SourceLocation(), &C.Idents.get(Name));
106}
107
108void Sema::ActOnTranslationUnitScope(SourceLocation Loc, Scope *S) {
109  TUScope = S;
110  PushDeclContext(S, Context.getTranslationUnitDecl());
111  if (!PP.getLangOptions().ObjC1) return;
112
113  // Synthesize "typedef struct objc_selector *SEL;"
114  RecordDecl *SelTag = CreateStructDecl(Context, "objc_selector");
115  PushOnScopeChains(SelTag, TUScope);
116
117  QualType SelT = Context.getPointerType(Context.getTagDeclType(SelTag));
118  TypedefDecl *SelTypedef = TypedefDecl::Create(Context, CurContext,
119                                                SourceLocation(),
120                                                &Context.Idents.get("SEL"),
121                                                SelT);
122  PushOnScopeChains(SelTypedef, TUScope);
123  Context.setObjCSelType(SelTypedef);
124
125  // FIXME: Make sure these don't leak!
126  RecordDecl *ClassTag = CreateStructDecl(Context, "objc_class");
127  QualType ClassT = Context.getPointerType(Context.getTagDeclType(ClassTag));
128  TypedefDecl *ClassTypedef =
129    TypedefDecl::Create(Context, CurContext, SourceLocation(),
130                        &Context.Idents.get("Class"), ClassT);
131  PushOnScopeChains(ClassTag, TUScope);
132  PushOnScopeChains(ClassTypedef, TUScope);
133  Context.setObjCClassType(ClassTypedef);
134  // Synthesize "@class Protocol;
135  ObjCInterfaceDecl *ProtocolDecl =
136    ObjCInterfaceDecl::Create(Context, CurContext, SourceLocation(),
137                              &Context.Idents.get("Protocol"),
138                              SourceLocation(), true);
139  Context.setObjCProtoType(Context.getObjCInterfaceType(ProtocolDecl));
140  PushOnScopeChains(ProtocolDecl, TUScope);
141
142  // Synthesize "typedef struct objc_object { Class isa; } *id;"
143  RecordDecl *ObjectTag = CreateStructDecl(Context, "objc_object");
144
145  QualType ObjT = Context.getPointerType(Context.getTagDeclType(ObjectTag));
146  PushOnScopeChains(ObjectTag, TUScope);
147  TypedefDecl *IdTypedef = TypedefDecl::Create(Context, CurContext,
148                                               SourceLocation(),
149                                               &Context.Idents.get("id"),
150                                               ObjT);
151  PushOnScopeChains(IdTypedef, TUScope);
152  Context.setObjCIdType(IdTypedef);
153}
154
155Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
156           bool CompleteTranslationUnit)
157  : LangOpts(pp.getLangOptions()), PP(pp), Context(ctxt), Consumer(consumer),
158    Diags(PP.getDiagnostics()),
159    SourceMgr(PP.getSourceManager()), CurContext(0), PreDeclaratorDC(0),
160    CurBlock(0), PackContext(0), IdResolver(pp.getLangOptions()),
161    GlobalNewDeleteDeclared(false),
162    CompleteTranslationUnit(CompleteTranslationUnit) {
163
164  // Get IdentifierInfo objects for known functions for which we
165  // do extra checking.
166  IdentifierTable &IT = PP.getIdentifierTable();
167
168  KnownFunctionIDs[id_NSLog]         = &IT.get("NSLog");
169  KnownFunctionIDs[id_NSLogv]         = &IT.get("NSLogv");
170  KnownFunctionIDs[id_asprintf]      = &IT.get("asprintf");
171  KnownFunctionIDs[id_vasprintf]     = &IT.get("vasprintf");
172
173  StdNamespace = 0;
174  TUScope = 0;
175  if (getLangOptions().CPlusPlus)
176    FieldCollector.reset(new CXXFieldCollector());
177
178  // Tell diagnostics how to render things from the AST library.
179  PP.getDiagnostics().SetArgToStringFn(ConvertArgToStringFn, &Context);
180}
181
182/// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit cast.
183/// If there is already an implicit cast, merge into the existing one.
184/// If isLvalue, the result of the cast is an lvalue.
185void Sema::ImpCastExprToType(Expr *&Expr, QualType Ty, bool isLvalue) {
186  QualType ExprTy = Context.getCanonicalType(Expr->getType());
187  QualType TypeTy = Context.getCanonicalType(Ty);
188
189  if (ExprTy == TypeTy)
190    return;
191
192  if (Expr->getType().getTypePtr()->isPointerType() &&
193      Ty.getTypePtr()->isPointerType()) {
194    QualType ExprBaseType =
195      cast<PointerType>(ExprTy.getUnqualifiedType())->getPointeeType();
196    QualType BaseType =
197      cast<PointerType>(TypeTy.getUnqualifiedType())->getPointeeType();
198    if (ExprBaseType.getAddressSpace() != BaseType.getAddressSpace()) {
199      Diag(Expr->getExprLoc(), diag::err_implicit_pointer_address_space_cast)
200        << Expr->getSourceRange();
201    }
202  }
203
204  if (ImplicitCastExpr *ImpCast = dyn_cast<ImplicitCastExpr>(Expr)) {
205    ImpCast->setType(Ty);
206    ImpCast->setLvalueCast(isLvalue);
207  } else
208    Expr = new (Context) ImplicitCastExpr(Ty, Expr, isLvalue);
209}
210
211void Sema::DeleteExpr(ExprTy *E) {
212  if (E) static_cast<Expr*>(E)->Destroy(Context);
213}
214void Sema::DeleteStmt(StmtTy *S) {
215  if (S) static_cast<Stmt*>(S)->Destroy(Context);
216}
217
218/// ActOnEndOfTranslationUnit - This is called at the very end of the
219/// translation unit when EOF is reached and all but the top-level scope is
220/// popped.
221void Sema::ActOnEndOfTranslationUnit() {
222  if (!CompleteTranslationUnit)
223    return;
224
225  // C99 6.9.2p2:
226  //   A declaration of an identifier for an object that has file
227  //   scope without an initializer, and without a storage-class
228  //   specifier or with the storage-class specifier static,
229  //   constitutes a tentative definition. If a translation unit
230  //   contains one or more tentative definitions for an identifier,
231  //   and the translation unit contains no external definition for
232  //   that identifier, then the behavior is exactly as if the
233  //   translation unit contains a file scope declaration of that
234  //   identifier, with the composite type as of the end of the
235  //   translation unit, with an initializer equal to 0.
236  for (llvm::DenseMap<DeclarationName, VarDecl *>::iterator
237         D = TentativeDefinitions.begin(),
238         DEnd = TentativeDefinitions.end();
239       D != DEnd; ++D) {
240    VarDecl *VD = D->second;
241
242    if (VD->isInvalidDecl() || !VD->isTentativeDefinition(Context))
243      continue;
244
245    if (const IncompleteArrayType *ArrayT
246        = Context.getAsIncompleteArrayType(VD->getType())) {
247      if (RequireCompleteType(VD->getLocation(),
248                              ArrayT->getElementType(),
249                              diag::err_tentative_def_incomplete_type_arr))
250        VD->setInvalidDecl();
251      else {
252        // Set the length of the array to 1 (C99 6.9.2p5).
253        Diag(VD->getLocation(),  diag::warn_tentative_incomplete_array);
254        llvm::APInt One(Context.getTypeSize(Context.getSizeType()),
255                        true);
256        QualType T
257          = Context.getConstantArrayType(ArrayT->getElementType(),
258                                         One, ArrayType::Normal, 0);
259        VD->setType(T);
260      }
261    } else if (RequireCompleteType(VD->getLocation(), VD->getType(),
262                                   diag::err_tentative_def_incomplete_type))
263      VD->setInvalidDecl();
264
265    // Notify the consumer that we've completed a tentative definition.
266    if (!VD->isInvalidDecl())
267      Consumer.CompleteTentativeDefinition(VD);
268
269  }
270}
271
272
273//===----------------------------------------------------------------------===//
274// Helper functions.
275//===----------------------------------------------------------------------===//
276
277/// getCurFunctionDecl - If inside of a function body, this returns a pointer
278/// to the function decl for the function being parsed.  If we're currently
279/// in a 'block', this returns the containing context.
280FunctionDecl *Sema::getCurFunctionDecl() {
281  DeclContext *DC = CurContext;
282  while (isa<BlockDecl>(DC))
283    DC = DC->getParent();
284  return dyn_cast<FunctionDecl>(DC);
285}
286
287ObjCMethodDecl *Sema::getCurMethodDecl() {
288  DeclContext *DC = CurContext;
289  while (isa<BlockDecl>(DC))
290    DC = DC->getParent();
291  return dyn_cast<ObjCMethodDecl>(DC);
292}
293
294NamedDecl *Sema::getCurFunctionOrMethodDecl() {
295  DeclContext *DC = CurContext;
296  while (isa<BlockDecl>(DC))
297    DC = DC->getParent();
298  if (isa<ObjCMethodDecl>(DC) || isa<FunctionDecl>(DC))
299    return cast<NamedDecl>(DC);
300  return 0;
301}
302
303Sema::SemaDiagnosticBuilder::~SemaDiagnosticBuilder() {
304  this->Emit();
305
306  // If this is not a note, and we're in a template instantiation
307  // that is different from the last template instantiation where
308  // we emitted an error, print a template instantiation
309  // backtrace.
310  if (!SemaRef.Diags.isBuiltinNote(DiagID) &&
311      !SemaRef.ActiveTemplateInstantiations.empty() &&
312      SemaRef.ActiveTemplateInstantiations.back()
313        != SemaRef.LastTemplateInstantiationErrorContext) {
314    SemaRef.PrintInstantiationStack();
315    SemaRef.LastTemplateInstantiationErrorContext
316      = SemaRef.ActiveTemplateInstantiations.back();
317  }
318}
319