lib/Sema/Sema.cpp

   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"
  21 #include "clang/Basic/TargetInfo.h"
  22 using namespace clang;
  23
  24 /// ConvertQualTypeToStringFn - This function is used to pretty print the
  25 /// specified QualType as a string in diagnostics.
  26 static void ConvertArgToStringFn(Diagnostic::ArgumentKind Kind, intptr_t Val,
  27                                  const char *Modifier, unsigned ModLen,
  28                                  const char *Argument, unsigned ArgLen,
  29                                  llvm::SmallVectorImpl<char> &Output,
  30                                  void *Cookie) {
  31   ASTContext &Context = *static_cast<ASTContext*>(Cookie);
  32
  33   std::string S;
  34   if (Kind == Diagnostic::ak_qualtype) {
  35     assert(ModLen == 0 && ArgLen == 0 &&
  36            "Invalid modifier for QualType argument");
  37
  38     QualType Ty(QualType::getFromOpaquePtr(reinterpret_cast<void*>(Val)));
  39
  40     // FIXME: Playing with std::string is really slow.
  41     S = Ty.getAsString(Context.PrintingPolicy);
  42
  43     // If this is a sugared type (like a typedef, typeof, etc), then unwrap one
  44     // level of the sugar so that the type is more obvious to the user.
  45     QualType DesugaredTy = Ty->getDesugaredType(true);
  46     DesugaredTy.setCVRQualifiers(DesugaredTy.getCVRQualifiers() |
  47                                  Ty.getCVRQualifiers());
  48
  49     if (Ty != DesugaredTy &&
  50         // If the desugared type is a vector type, we don't want to expand it,
  51         // it will turn into an attribute mess. People want their "vec4".
  52         !isa<VectorType>(DesugaredTy) &&
  53
  54         // Don't desugar magic Objective-C types.
  55         Ty.getUnqualifiedType() != Context.getObjCIdType() &&
  56         Ty.getUnqualifiedType() != Context.getObjCSelType() &&
  57         Ty.getUnqualifiedType() != Context.getObjCProtoType() &&
  58         Ty.getUnqualifiedType() != Context.getObjCClassType() &&
  59
  60         // Not va_list.
  61         Ty.getUnqualifiedType() != Context.getBuiltinVaListType()) {
  62       S = "'"+S+"' (aka '";
  63       S += DesugaredTy.getAsString(Context.PrintingPolicy);
  64       S += "')";
  65       Output.append(S.begin(), S.end());
  66       return;
  67     }
  68
  69   } else if (Kind == Diagnostic::ak_declarationname) {
  70
  71     DeclarationName N = DeclarationName::getFromOpaqueInteger(Val);
  72     S = N.getAsString();
  73
  74     if (ModLen == 9 && !memcmp(Modifier, "objcclass", 9) && ArgLen == 0)
  75       S = '+' + S;
  76     else if (ModLen == 12 && !memcmp(Modifier, "objcinstance", 12) && ArgLen==0)
  77       S = '-' + S;
  78     else
  79       assert(ModLen == 0 && ArgLen == 0 &&
  80              "Invalid modifier for DeclarationName argument");
  81   } else {
  82     assert(Kind == Diagnostic::ak_nameddecl);
  83     if (ModLen == 1 && Modifier[0] == 'q' && ArgLen == 0)
  84       S = reinterpret_cast<NamedDecl*>(Val)->getQualifiedNameAsString();
  85     else {
  86       assert(ModLen == 0 && ArgLen == 0 &&
  87            "Invalid modifier for NamedDecl* argument");
  88       S = reinterpret_cast<NamedDecl*>(Val)->getNameAsString();
  89     }
  90   }
  91
  92   Output.push_back('\'');
  93   Output.append(S.begin(), S.end());
  94   Output.push_back('\'');
  95 }
  96
  97
  98 static inline RecordDecl *CreateStructDecl(ASTContext &C, const char *Name) {
  99   if (C.getLangOptions().CPlusPlus)
 100     return CXXRecordDecl::Create(C, TagDecl::TK_struct,
 101                                  C.getTranslationUnitDecl(),
 102                                  SourceLocation(), &C.Idents.get(Name));
 103
 104   return RecordDecl::Create(C, TagDecl::TK_struct,
 105                             C.getTranslationUnitDecl(),
 106                             SourceLocation(), &C.Idents.get(Name));
 107 }
 108
 109 void Sema::ActOnTranslationUnitScope(SourceLocation Loc, Scope *S) {
 110   TUScope = S;
 111   PushDeclContext(S, Context.getTranslationUnitDecl());
 112
 113   if (PP.getTargetInfo().getPointerWidth(0) >= 64) {
 114     // Install [u]int128_t for 64-bit targets.
 115     PushOnScopeChains(TypedefDecl::Create(Context, CurContext,
 116                                           SourceLocation(),
 117                                           &Context.Idents.get("__int128_t"),
 118                                           Context.Int128Ty), TUScope);
 119     PushOnScopeChains(TypedefDecl::Create(Context, CurContext,
 120                                           SourceLocation(),
 121                                           &Context.Idents.get("__uint128_t"),
 122                                           Context.UnsignedInt128Ty), TUScope);
 123   }
 124
 125
 126   if (!PP.getLangOptions().ObjC1) return;
 127
 128   if (Context.getObjCSelType().isNull()) {
 129     // Synthesize "typedef struct objc_selector *SEL;"
 130     RecordDecl *SelTag = CreateStructDecl(Context, "objc_selector");
 131     PushOnScopeChains(SelTag, TUScope);
 132
 133     QualType SelT = Context.getPointerType(Context.getTagDeclType(SelTag));
 134     TypedefDecl *SelTypedef = TypedefDecl::Create(Context, CurContext,
 135                                                   SourceLocation(),
 136                                                   &Context.Idents.get("SEL"),
 137                                                   SelT);
 138     PushOnScopeChains(SelTypedef, TUScope);
 139     Context.setObjCSelType(Context.getTypeDeclType(SelTypedef));
 140   }
 141
 142   if (Context.getObjCClassType().isNull()) {
 143     RecordDecl *ClassTag = CreateStructDecl(Context, "objc_class");
 144     QualType ClassT = Context.getPointerType(Context.getTagDeclType(ClassTag));
 145     TypedefDecl *ClassTypedef =
 146       TypedefDecl::Create(Context, CurContext, SourceLocation(),
 147                           &Context.Idents.get("Class"), ClassT);
 148     PushOnScopeChains(ClassTag, TUScope);
 149     PushOnScopeChains(ClassTypedef, TUScope);
 150     Context.setObjCClassType(Context.getTypeDeclType(ClassTypedef));
 151   }
 152
 153   // Synthesize "@class Protocol;
 154   if (Context.getObjCProtoType().isNull()) {
 155     ObjCInterfaceDecl *ProtocolDecl =
 156       ObjCInterfaceDecl::Create(Context, CurContext, SourceLocation(),
 157                                 &Context.Idents.get("Protocol"),
 158                                 SourceLocation(), true);
 159     Context.setObjCProtoType(Context.getObjCInterfaceType(ProtocolDecl));
 160     PushOnScopeChains(ProtocolDecl, TUScope);
 161   }
 162
 163   // Synthesize "typedef struct objc_object { Class isa; } *id;"
 164   if (Context.getObjCIdType().isNull()) {
 165     RecordDecl *ObjectTag = CreateStructDecl(Context, "objc_object");
 166
 167     QualType ObjT = Context.getPointerType(Context.getTagDeclType(ObjectTag));
 168     PushOnScopeChains(ObjectTag, TUScope);
 169     TypedefDecl *IdTypedef = TypedefDecl::Create(Context, CurContext,
 170                                                  SourceLocation(),
 171                                                  &Context.Idents.get("id"),
 172                                                  ObjT);
 173     PushOnScopeChains(IdTypedef, TUScope);
 174     Context.setObjCIdType(Context.getTypeDeclType(IdTypedef));
 175   }
 176 }
 177
 178 Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
 179            bool CompleteTranslationUnit)
 180   : LangOpts(pp.getLangOptions()), PP(pp), Context(ctxt), Consumer(consumer),
 181     Diags(PP.getDiagnostics()), SourceMgr(PP.getSourceManager()),
 182     ExternalSource(0), CurContext(0), PreDeclaratorDC(0),
 183     CurBlock(0), PackContext(0), IdResolver(pp.getLangOptions()),
 184     GlobalNewDeleteDeclared(false),
 185     CompleteTranslationUnit(CompleteTranslationUnit),
 186     CurrentInstantiationScope(0) {
 187
 188   StdNamespace = 0;
 189   TUScope = 0;
 190   if (getLangOptions().CPlusPlus)
 191     FieldCollector.reset(new CXXFieldCollector());
 192
 193   // Tell diagnostics how to render things from the AST library.
 194   PP.getDiagnostics().SetArgToStringFn(ConvertArgToStringFn, &Context);
 195 }
 196
 197 /// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit cast.
 198 /// If there is already an implicit cast, merge into the existing one.
 199 /// If isLvalue, the result of the cast is an lvalue.
 200 void Sema::ImpCastExprToType(Expr *&Expr, QualType Ty, bool isLvalue) {
 201   QualType ExprTy = Context.getCanonicalType(Expr->getType());
 202   QualType TypeTy = Context.getCanonicalType(Ty);
 203
 204   if (ExprTy == TypeTy)
 205     return;
 206
 207   if (Expr->getType().getTypePtr()->isPointerType() &&
 208       Ty.getTypePtr()->isPointerType()) {
 209     QualType ExprBaseType =
 210       cast<PointerType>(ExprTy.getUnqualifiedType())->getPointeeType();
 211     QualType BaseType =
 212       cast<PointerType>(TypeTy.getUnqualifiedType())->getPointeeType();
 213     if (ExprBaseType.getAddressSpace() != BaseType.getAddressSpace()) {
 214       Diag(Expr->getExprLoc(), diag::err_implicit_pointer_address_space_cast)
 215         << Expr->getSourceRange();
 216     }
 217   }
 218
 219   if (ImplicitCastExpr *ImpCast = dyn_cast<ImplicitCastExpr>(Expr)) {
 220     ImpCast->setType(Ty);
 221     ImpCast->setLvalueCast(isLvalue);
 222   } else
 223     Expr = new (Context) ImplicitCastExpr(Ty, Expr, isLvalue);
 224 }
 225
 226 void Sema::DeleteExpr(ExprTy *E) {
 227   if (E) static_cast<Expr*>(E)->Destroy(Context);
 228 }
 229 void Sema::DeleteStmt(StmtTy *S) {
 230   if (S) static_cast<Stmt*>(S)->Destroy(Context);
 231 }
 232
 233 /// ActOnEndOfTranslationUnit - This is called at the very end of the
 234 /// translation unit when EOF is reached and all but the top-level scope is
 235 /// popped.
 236 void Sema::ActOnEndOfTranslationUnit() {
 237   if (!CompleteTranslationUnit)
 238     return;
 239
 240   // C99 6.9.2p2:
 241   //   A declaration of an identifier for an object that has file
 242   //   scope without an initializer, and without a storage-class
 243   //   specifier or with the storage-class specifier static,
 244   //   constitutes a tentative definition. If a translation unit
 245   //   contains one or more tentative definitions for an identifier,
 246   //   and the translation unit contains no external definition for
 247   //   that identifier, then the behavior is exactly as if the
 248   //   translation unit contains a file scope declaration of that
 249   //   identifier, with the composite type as of the end of the
 250   //   translation unit, with an initializer equal to 0.
 251   for (llvm::DenseMap<DeclarationName, VarDecl *>::iterator
 252          D = TentativeDefinitions.begin(),
 253          DEnd = TentativeDefinitions.end();
 254        D != DEnd; ++D) {
 255     VarDecl *VD = D->second;
 256
 257     if (VD->isInvalidDecl() || !VD->isTentativeDefinition(Context))
 258       continue;
 259
 260     if (const IncompleteArrayType *ArrayT
 261         = Context.getAsIncompleteArrayType(VD->getType())) {
 262       if (RequireCompleteType(VD->getLocation(),
 263                               ArrayT->getElementType(),
 264                               diag::err_tentative_def_incomplete_type_arr))
 265         VD->setInvalidDecl();
 266       else {
 267         // Set the length of the array to 1 (C99 6.9.2p5).
 268         Diag(VD->getLocation(),  diag::warn_tentative_incomplete_array);
 269         llvm::APInt One(Context.getTypeSize(Context.getSizeType()),
 270                         true);
 271         QualType T
 272           = Context.getConstantArrayType(ArrayT->getElementType(),
 273                                          One, ArrayType::Normal, 0);
 274         VD->setType(T);
 275       }
 276     } else if (RequireCompleteType(VD->getLocation(), VD->getType(),
 277                                    diag::err_tentative_def_incomplete_type))
 278       VD->setInvalidDecl();
 279
 280     // Notify the consumer that we've completed a tentative definition.
 281     if (!VD->isInvalidDecl())
 282       Consumer.CompleteTentativeDefinition(VD);
 283
 284   }
 285 }
 286
 287
 288 //===----------------------------------------------------------------------===//
 289 // Helper functions.
 290 //===----------------------------------------------------------------------===//
 291
 292 /// getCurFunctionDecl - If inside of a function body, this returns a pointer
 293 /// to the function decl for the function being parsed.  If we're currently
 294 /// in a 'block', this returns the containing context.
 295 FunctionDecl *Sema::getCurFunctionDecl() {
 296   DeclContext *DC = CurContext;
 297   while (isa<BlockDecl>(DC))
 298     DC = DC->getParent();
 299   return dyn_cast<FunctionDecl>(DC);
 300 }
 301
 302 ObjCMethodDecl *Sema::getCurMethodDecl() {
 303   DeclContext *DC = CurContext;
 304   while (isa<BlockDecl>(DC))
 305     DC = DC->getParent();
 306   return dyn_cast<ObjCMethodDecl>(DC);
 307 }
 308
 309 NamedDecl *Sema::getCurFunctionOrMethodDecl() {
 310   DeclContext *DC = CurContext;
 311   while (isa<BlockDecl>(DC))
 312     DC = DC->getParent();
 313   if (isa<ObjCMethodDecl>(DC) || isa<FunctionDecl>(DC))
 314     return cast<NamedDecl>(DC);
 315   return 0;
 316 }
 317
 318 Sema::SemaDiagnosticBuilder::~SemaDiagnosticBuilder() {
 319   this->Emit();
 320
 321   // If this is not a note, and we're in a template instantiation
 322   // that is different from the last template instantiation where
 323   // we emitted an error, print a template instantiation
 324   // backtrace.
 325   if (!SemaRef.Diags.isBuiltinNote(DiagID) &&
 326       !SemaRef.ActiveTemplateInstantiations.empty() &&
 327       SemaRef.ActiveTemplateInstantiations.back()
 328         != SemaRef.LastTemplateInstantiationErrorContext) {
 329     SemaRef.PrintInstantiationStack();
 330     SemaRef.LastTemplateInstantiationErrorContext
 331       = SemaRef.ActiveTemplateInstantiations.back();
 332   }
 333 }