Sema.cpp revision 1eb4433ac451dc16f4133a88af2d002ac26c58ef 
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 "llvm/ADT/DenseMap.h"
17#include "clang/AST/ASTConsumer.h"
18#include "clang/AST/ASTContext.h"
19#include "clang/AST/DeclObjC.h"
20#include "clang/AST/Expr.h"
21#include "clang/Lex/Preprocessor.h"
22#include "clang/Basic/PartialDiagnostic.h"
23#include "clang/Basic/TargetInfo.h"
24using namespace clang;
25
26/// ConvertQualTypeToStringFn - This function is used to pretty print the
27/// specified QualType as a string in diagnostics.
28static void ConvertArgToStringFn(Diagnostic::ArgumentKind Kind, intptr_t Val,
29                                 const char *Modifier, unsigned ModLen,
30                                 const char *Argument, unsigned ArgLen,
31                                 llvm::SmallVectorImpl<char> &Output,
32                                 void *Cookie) {
33  ASTContext &Context = *static_cast<ASTContext*>(Cookie);
34
35  std::string S;
36  if (Kind == Diagnostic::ak_qualtype) {
37    assert(ModLen == 0 && ArgLen == 0 &&
38           "Invalid modifier for QualType argument");
39
40    QualType Ty(QualType::getFromOpaquePtr(reinterpret_cast<void*>(Val)));
41
42    // FIXME: Playing with std::string is really slow.
43    S = Ty.getAsString(Context.PrintingPolicy);
44
45    // If this is a sugared type (like a typedef, typeof, etc), then unwrap one
46    // level of the sugar so that the type is more obvious to the user.
47    QualType DesugaredTy = Ty->getDesugaredType(true);
48    DesugaredTy.setCVRQualifiers(DesugaredTy.getCVRQualifiers() |
49                                 Ty.getCVRQualifiers());
50
51    if (Ty != DesugaredTy &&
52        // If the desugared type is a vector type, we don't want to expand it,
53        // it will turn into an attribute mess. People want their "vec4".
54        !isa<VectorType>(DesugaredTy) &&
55
56        // Don't aka just because we saw an elaborated type.
57        (!isa<ElaboratedType>(Ty) ||
58         cast<ElaboratedType>(Ty)->getUnderlyingType() != DesugaredTy) &&
59
60        // Don't desugar magic Objective-C types.
61        Ty.getUnqualifiedType() != Context.getObjCIdType() &&
62        Ty.getUnqualifiedType() != Context.getObjCClassType() &&
63        Ty.getUnqualifiedType() != Context.getObjCSelType() &&
64        Ty.getUnqualifiedType() != Context.getObjCProtoType() &&
65
66        // Not va_list.
67        Ty.getUnqualifiedType() != Context.getBuiltinVaListType()) {
68      S = "'"+S+"' (aka '";
69      S += DesugaredTy.getAsString(Context.PrintingPolicy);
70      S += "')";
71      Output.append(S.begin(), S.end());
72      return;
73    }
74
75  } else if (Kind == Diagnostic::ak_declarationname) {
76
77    DeclarationName N = DeclarationName::getFromOpaqueInteger(Val);
78    S = N.getAsString();
79
80    if (ModLen == 9 && !memcmp(Modifier, "objcclass", 9) && ArgLen == 0)
81      S = '+' + S;
82    else if (ModLen == 12 && !memcmp(Modifier, "objcinstance", 12) && ArgLen==0)
83      S = '-' + S;
84    else
85      assert(ModLen == 0 && ArgLen == 0 &&
86             "Invalid modifier for DeclarationName argument");
87  } else if (Kind == Diagnostic::ak_nameddecl) {
88    if (ModLen == 1 && Modifier[0] == 'q' && ArgLen == 0)
89      S = reinterpret_cast<NamedDecl*>(Val)->getQualifiedNameAsString();
90    else {
91      assert(ModLen == 0 && ArgLen == 0 &&
92           "Invalid modifier for NamedDecl* argument");
93      S = reinterpret_cast<NamedDecl*>(Val)->getNameAsString();
94    }
95  } else {
96    llvm::raw_string_ostream OS(S);
97    assert(Kind == Diagnostic::ak_nestednamespec);
98    reinterpret_cast<NestedNameSpecifier*> (Val)->print(OS,
99                                                        Context.PrintingPolicy);
100  }
101
102  Output.push_back('\'');
103  Output.append(S.begin(), S.end());
104  Output.push_back('\'');
105}
106
107
108static inline RecordDecl *CreateStructDecl(ASTContext &C, const char *Name) {
109  if (C.getLangOptions().CPlusPlus)
110    return CXXRecordDecl::Create(C, TagDecl::TK_struct,
111                                 C.getTranslationUnitDecl(),
112                                 SourceLocation(), &C.Idents.get(Name));
113
114  return RecordDecl::Create(C, TagDecl::TK_struct,
115                            C.getTranslationUnitDecl(),
116                            SourceLocation(), &C.Idents.get(Name));
117}
118
119void Sema::ActOnTranslationUnitScope(SourceLocation Loc, Scope *S) {
120  TUScope = S;
121  PushDeclContext(S, Context.getTranslationUnitDecl());
122
123  if (PP.getTargetInfo().getPointerWidth(0) >= 64) {
124    // Install [u]int128_t for 64-bit targets.
125    PushOnScopeChains(TypedefDecl::Create(Context, CurContext,
126                                          SourceLocation(),
127                                          &Context.Idents.get("__int128_t"),
128                                          Context.Int128Ty), TUScope);
129    PushOnScopeChains(TypedefDecl::Create(Context, CurContext,
130                                          SourceLocation(),
131                                          &Context.Idents.get("__uint128_t"),
132                                          Context.UnsignedInt128Ty), TUScope);
133  }
134
135
136  if (!PP.getLangOptions().ObjC1) return;
137
138  // Built-in ObjC types may already be set by PCHReader (hence isNull checks).
139  if (Context.getObjCSelType().isNull()) {
140    // Synthesize "typedef struct objc_selector *SEL;"
141    RecordDecl *SelTag = CreateStructDecl(Context, "objc_selector");
142    PushOnScopeChains(SelTag, TUScope);
143
144    QualType SelT = Context.getPointerType(Context.getTagDeclType(SelTag));
145    TypedefDecl *SelTypedef = TypedefDecl::Create(Context, CurContext,
146                                                  SourceLocation(),
147                                                  &Context.Idents.get("SEL"),
148                                                  SelT);
149    PushOnScopeChains(SelTypedef, TUScope);
150    Context.setObjCSelType(Context.getTypeDeclType(SelTypedef));
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  // Create the built-in typedef for 'id'.
163  if (Context.getObjCIdType().isNull()) {
164    TypedefDecl *IdTypedef =
165      TypedefDecl::Create(
166        Context, CurContext, SourceLocation(), &Context.Idents.get("id"),
167        Context.getObjCObjectPointerType(Context.ObjCBuiltinIdTy)
168      );
169    PushOnScopeChains(IdTypedef, TUScope);
170    Context.setObjCIdType(Context.getTypeDeclType(IdTypedef));
171    Context.ObjCIdRedefinitionType = Context.getObjCIdType();
172  }
173  // Create the built-in typedef for 'Class'.
174  if (Context.getObjCClassType().isNull()) {
175    TypedefDecl *ClassTypedef =
176      TypedefDecl::Create(
177        Context, CurContext, SourceLocation(), &Context.Idents.get("Class"),
178        Context.getObjCObjectPointerType(Context.ObjCBuiltinClassTy)
179      );
180    PushOnScopeChains(ClassTypedef, TUScope);
181    Context.setObjCClassType(Context.getTypeDeclType(ClassTypedef));
182    Context.ObjCClassRedefinitionType = Context.getObjCClassType();
183  }
184}
185
186Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
187           bool CompleteTranslationUnit)
188  : LangOpts(pp.getLangOptions()), PP(pp), Context(ctxt), Consumer(consumer),
189    Diags(PP.getDiagnostics()), SourceMgr(PP.getSourceManager()),
190    ExternalSource(0), CurContext(0), PreDeclaratorDC(0),
191    CurBlock(0), PackContext(0), IdResolver(pp.getLangOptions()),
192    GlobalNewDeleteDeclared(false), ExprEvalContext(PotentiallyEvaluated),
193    CompleteTranslationUnit(CompleteTranslationUnit),
194    NumSFINAEErrors(0), CurrentInstantiationScope(0) {
195
196  StdNamespace = 0;
197  TUScope = 0;
198  if (getLangOptions().CPlusPlus)
199    FieldCollector.reset(new CXXFieldCollector());
200
201  // Tell diagnostics how to render things from the AST library.
202  PP.getDiagnostics().SetArgToStringFn(ConvertArgToStringFn, &Context);
203}
204
205/// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit cast.
206/// If there is already an implicit cast, merge into the existing one.
207/// If isLvalue, the result of the cast is an lvalue.
208void Sema::ImpCastExprToType(Expr *&Expr, QualType Ty,
209                             const CastExpr::CastInfo &Info, bool isLvalue) {
210  QualType ExprTy = Context.getCanonicalType(Expr->getType());
211  QualType TypeTy = Context.getCanonicalType(Ty);
212
213  if (ExprTy == TypeTy)
214    return;
215
216  if (Expr->getType().getTypePtr()->isPointerType() &&
217      Ty.getTypePtr()->isPointerType()) {
218    QualType ExprBaseType =
219      cast<PointerType>(ExprTy.getUnqualifiedType())->getPointeeType();
220    QualType BaseType =
221      cast<PointerType>(TypeTy.getUnqualifiedType())->getPointeeType();
222    if (ExprBaseType.getAddressSpace() != BaseType.getAddressSpace()) {
223      Diag(Expr->getExprLoc(), diag::err_implicit_pointer_address_space_cast)
224        << Expr->getSourceRange();
225    }
226  }
227
228  if (ImplicitCastExpr *ImpCast = dyn_cast<ImplicitCastExpr>(Expr)) {
229    ImpCast->setType(Ty);
230    ImpCast->setLvalueCast(isLvalue);
231  } else
232    Expr = new (Context) ImplicitCastExpr(Ty, Info, Expr,
233                                          isLvalue);
234}
235
236void Sema::DeleteExpr(ExprTy *E) {
237  if (E) static_cast<Expr*>(E)->Destroy(Context);
238}
239void Sema::DeleteStmt(StmtTy *S) {
240  if (S) static_cast<Stmt*>(S)->Destroy(Context);
241}
242
243/// ActOnEndOfTranslationUnit - This is called at the very end of the
244/// translation unit when EOF is reached and all but the top-level scope is
245/// popped.
246void Sema::ActOnEndOfTranslationUnit() {
247  // C++: Perform implicit template instantiations.
248  //
249  // FIXME: When we perform these implicit instantiations, we do not carefully
250  // keep track of the point of instantiation (C++ [temp.point]). This means
251  // that name lookup that occurs within the template instantiation will
252  // always happen at the end of the translation unit, so it will find
253  // some names that should not be found. Although this is common behavior
254  // for C++ compilers, it is technically wrong. In the future, we either need
255  // to be able to filter the results of name lookup or we need to perform
256  // template instantiations earlier.
257  PerformPendingImplicitInstantiations();
258
259  // Check for #pragma weak identifiers that were never declared
260  // FIXME: This will cause diagnostics to be emitted in a non-determinstic
261  // order!  Iterating over a densemap like this is bad.
262  for (llvm::DenseMap<IdentifierInfo*,WeakInfo>::iterator
263       I = WeakUndeclaredIdentifiers.begin(),
264       E = WeakUndeclaredIdentifiers.end(); I != E; ++I) {
265    if (I->second.getUsed()) continue;
266
267    Diag(I->second.getLocation(), diag::warn_weak_identifier_undeclared)
268      << I->first;
269  }
270
271  if (!CompleteTranslationUnit)
272    return;
273
274  // C99 6.9.2p2:
275  //   A declaration of an identifier for an object that has file
276  //   scope without an initializer, and without a storage-class
277  //   specifier or with the storage-class specifier static,
278  //   constitutes a tentative definition. If a translation unit
279  //   contains one or more tentative definitions for an identifier,
280  //   and the translation unit contains no external definition for
281  //   that identifier, then the behavior is exactly as if the
282  //   translation unit contains a file scope declaration of that
283  //   identifier, with the composite type as of the end of the
284  //   translation unit, with an initializer equal to 0.
285  for (unsigned i = 0, e = TentativeDefinitionList.size(); i != e; ++i) {
286    VarDecl *VD = TentativeDefinitions.lookup(TentativeDefinitionList[i]);
287
288    // If the tentative definition was completed, it will be in the list, but
289    // not the map.
290    if (VD == 0 || VD->isInvalidDecl() || !VD->isTentativeDefinition(Context))
291      continue;
292
293    if (const IncompleteArrayType *ArrayT
294        = Context.getAsIncompleteArrayType(VD->getType())) {
295      if (RequireCompleteType(VD->getLocation(),
296                              ArrayT->getElementType(),
297                              diag::err_tentative_def_incomplete_type_arr)) {
298        VD->setInvalidDecl();
299        continue;
300      }
301
302      // Set the length of the array to 1 (C99 6.9.2p5).
303      Diag(VD->getLocation(), diag::warn_tentative_incomplete_array);
304      llvm::APInt One(Context.getTypeSize(Context.getSizeType()), true);
305      QualType T
306        = Context.getConstantArrayWithoutExprType(ArrayT->getElementType(),
307                                                  One, ArrayType::Normal, 0);
308      VD->setType(T);
309    } else if (RequireCompleteType(VD->getLocation(), VD->getType(),
310                                   diag::err_tentative_def_incomplete_type))
311      VD->setInvalidDecl();
312
313    // Notify the consumer that we've completed a tentative definition.
314    if (!VD->isInvalidDecl())
315      Consumer.CompleteTentativeDefinition(VD);
316
317  }
318}
319
320
321//===----------------------------------------------------------------------===//
322// Helper functions.
323//===----------------------------------------------------------------------===//
324
325DeclContext *Sema::getFunctionLevelDeclContext() {
326  DeclContext *DC = PreDeclaratorDC ? PreDeclaratorDC : CurContext;
327
328  while (isa<BlockDecl>(DC))
329    DC = DC->getParent();
330
331  return DC;
332}
333
334/// getCurFunctionDecl - If inside of a function body, this returns a pointer
335/// to the function decl for the function being parsed.  If we're currently
336/// in a 'block', this returns the containing context.
337FunctionDecl *Sema::getCurFunctionDecl() {
338  DeclContext *DC = getFunctionLevelDeclContext();
339  return dyn_cast<FunctionDecl>(DC);
340}
341
342ObjCMethodDecl *Sema::getCurMethodDecl() {
343  DeclContext *DC = getFunctionLevelDeclContext();
344  return dyn_cast<ObjCMethodDecl>(DC);
345}
346
347NamedDecl *Sema::getCurFunctionOrMethodDecl() {
348  DeclContext *DC = getFunctionLevelDeclContext();
349  if (isa<ObjCMethodDecl>(DC) || isa<FunctionDecl>(DC))
350    return cast<NamedDecl>(DC);
351  return 0;
352}
353
354void Sema::DiagnoseMissingMember(SourceLocation MemberLoc,
355                                 DeclarationName Member,
356                                 NestedNameSpecifier *NNS, SourceRange Range) {
357  switch (NNS->getKind()) {
358  default: assert(0 && "Unexpected nested name specifier kind!");
359  case NestedNameSpecifier::TypeSpec: {
360    const Type *Ty = Context.getCanonicalType(NNS->getAsType());
361    RecordDecl *RD = cast<RecordType>(Ty)->getDecl();
362    Diag(MemberLoc, diag::err_typecheck_record_no_member)
363      << Member << RD->getTagKind() << RD << Range;
364    break;
365  }
366  case NestedNameSpecifier::Namespace: {
367    Diag(MemberLoc, diag::err_typecheck_namespace_no_member)
368       << Member << NNS->getAsNamespace() << Range;
369    break;
370  }
371  case NestedNameSpecifier::Global: {
372    Diag(MemberLoc, diag::err_typecheck_global_namespace_no_member)
373      << Member << Range;
374    break;
375  }
376  }
377}
378
379Sema::SemaDiagnosticBuilder::~SemaDiagnosticBuilder() {
380  if (!this->Emit())
381    return;
382
383  // If this is not a note, and we're in a template instantiation
384  // that is different from the last template instantiation where
385  // we emitted an error, print a template instantiation
386  // backtrace.
387  if (!SemaRef.Diags.isBuiltinNote(DiagID) &&
388      !SemaRef.ActiveTemplateInstantiations.empty() &&
389      SemaRef.ActiveTemplateInstantiations.back()
390        != SemaRef.LastTemplateInstantiationErrorContext) {
391    SemaRef.PrintInstantiationStack();
392    SemaRef.LastTemplateInstantiationErrorContext
393      = SemaRef.ActiveTemplateInstantiations.back();
394  }
395}
396
397Sema::SemaDiagnosticBuilder
398Sema::Diag(SourceLocation Loc, const PartialDiagnostic& PD) {
399  SemaDiagnosticBuilder Builder(Diag(Loc, PD.getDiagID()));
400  PD.Emit(Builder);
401
402  return Builder;
403}
404
405void Sema::ActOnComment(SourceRange Comment) {
406  Context.Comments.push_back(Comment);
407}
408
409