Sema.cpp revision 2df9ced9fd1e8c7d7b38443db07e0e811de22571 
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
112  // Install [u]int128_t.
113  PushOnScopeChains(TypedefDecl::Create(Context, CurContext,
114                                        SourceLocation(),
115                                        &Context.Idents.get("__int128_t"),
116                                        Context.Int128Ty), TUScope);
117  PushOnScopeChains(TypedefDecl::Create(Context, CurContext,
118                                        SourceLocation(),
119                                        &Context.Idents.get("__uint128_t"),
120                                        Context.UnsignedInt128Ty), TUScope);
121
122
123  if (!PP.getLangOptions().ObjC1) return;
124
125  if (Context.getObjCSelType().isNull()) {
126    // Synthesize "typedef struct objc_selector *SEL;"
127    RecordDecl *SelTag = CreateStructDecl(Context, "objc_selector");
128    PushOnScopeChains(SelTag, TUScope);
129
130    QualType SelT = Context.getPointerType(Context.getTagDeclType(SelTag));
131    TypedefDecl *SelTypedef = TypedefDecl::Create(Context, CurContext,
132                                                  SourceLocation(),
133                                                  &Context.Idents.get("SEL"),
134                                                  SelT);
135    PushOnScopeChains(SelTypedef, TUScope);
136    Context.setObjCSelType(Context.getTypeDeclType(SelTypedef));
137  }
138
139  if (Context.getObjCClassType().isNull()) {
140    RecordDecl *ClassTag = CreateStructDecl(Context, "objc_class");
141    QualType ClassT = Context.getPointerType(Context.getTagDeclType(ClassTag));
142    TypedefDecl *ClassTypedef =
143      TypedefDecl::Create(Context, CurContext, SourceLocation(),
144                          &Context.Idents.get("Class"), ClassT);
145    PushOnScopeChains(ClassTag, TUScope);
146    PushOnScopeChains(ClassTypedef, TUScope);
147    Context.setObjCClassType(Context.getTypeDeclType(ClassTypedef));
148  }
149
150  // Synthesize "@class Protocol;
151  if (Context.getObjCProtoType().isNull()) {
152    ObjCInterfaceDecl *ProtocolDecl =
153      ObjCInterfaceDecl::Create(Context, CurContext, SourceLocation(),
154                                &Context.Idents.get("Protocol"),
155                                SourceLocation(), true);
156    Context.setObjCProtoType(Context.getObjCInterfaceType(ProtocolDecl));
157    PushOnScopeChains(ProtocolDecl, TUScope);
158  }
159
160  // Synthesize "typedef struct objc_object { Class isa; } *id;"
161  if (Context.getObjCIdType().isNull()) {
162    RecordDecl *ObjectTag = CreateStructDecl(Context, "objc_object");
163
164    QualType ObjT = Context.getPointerType(Context.getTagDeclType(ObjectTag));
165    PushOnScopeChains(ObjectTag, TUScope);
166    TypedefDecl *IdTypedef = TypedefDecl::Create(Context, CurContext,
167                                                 SourceLocation(),
168                                                 &Context.Idents.get("id"),
169                                                 ObjT);
170    PushOnScopeChains(IdTypedef, TUScope);
171    Context.setObjCIdType(Context.getTypeDeclType(IdTypedef));
172  }
173}
174
175Sema::Sema(Preprocessor &pp, ASTContext &ctxt, ASTConsumer &consumer,
176           bool CompleteTranslationUnit)
177  : LangOpts(pp.getLangOptions()), PP(pp), Context(ctxt), Consumer(consumer),
178    Diags(PP.getDiagnostics()), SourceMgr(PP.getSourceManager()),
179    ExternalSource(0), CurContext(0), PreDeclaratorDC(0),
180    CurBlock(0), PackContext(0), IdResolver(pp.getLangOptions()),
181    GlobalNewDeleteDeclared(false),
182    CompleteTranslationUnit(CompleteTranslationUnit) {
183
184  StdNamespace = 0;
185  TUScope = 0;
186  if (getLangOptions().CPlusPlus)
187    FieldCollector.reset(new CXXFieldCollector());
188
189  // Tell diagnostics how to render things from the AST library.
190  PP.getDiagnostics().SetArgToStringFn(ConvertArgToStringFn, &Context);
191}
192
193/// ImpCastExprToType - If Expr is not of type 'Type', insert an implicit cast.
194/// If there is already an implicit cast, merge into the existing one.
195/// If isLvalue, the result of the cast is an lvalue.
196void Sema::ImpCastExprToType(Expr *&Expr, QualType Ty, bool isLvalue) {
197  QualType ExprTy = Context.getCanonicalType(Expr->getType());
198  QualType TypeTy = Context.getCanonicalType(Ty);
199
200  if (ExprTy == TypeTy)
201    return;
202
203  if (Expr->getType().getTypePtr()->isPointerType() &&
204      Ty.getTypePtr()->isPointerType()) {
205    QualType ExprBaseType =
206      cast<PointerType>(ExprTy.getUnqualifiedType())->getPointeeType();
207    QualType BaseType =
208      cast<PointerType>(TypeTy.getUnqualifiedType())->getPointeeType();
209    if (ExprBaseType.getAddressSpace() != BaseType.getAddressSpace()) {
210      Diag(Expr->getExprLoc(), diag::err_implicit_pointer_address_space_cast)
211        << Expr->getSourceRange();
212    }
213  }
214
215  if (ImplicitCastExpr *ImpCast = dyn_cast<ImplicitCastExpr>(Expr)) {
216    ImpCast->setType(Ty);
217    ImpCast->setLvalueCast(isLvalue);
218  } else
219    Expr = new (Context) ImplicitCastExpr(Ty, Expr, isLvalue);
220}
221
222void Sema::DeleteExpr(ExprTy *E) {
223  if (E) static_cast<Expr*>(E)->Destroy(Context);
224}
225void Sema::DeleteStmt(StmtTy *S) {
226  if (S) static_cast<Stmt*>(S)->Destroy(Context);
227}
228
229/// ActOnEndOfTranslationUnit - This is called at the very end of the
230/// translation unit when EOF is reached and all but the top-level scope is
231/// popped.
232void Sema::ActOnEndOfTranslationUnit() {
233  if (!CompleteTranslationUnit)
234    return;
235
236  // C99 6.9.2p2:
237  //   A declaration of an identifier for an object that has file
238  //   scope without an initializer, and without a storage-class
239  //   specifier or with the storage-class specifier static,
240  //   constitutes a tentative definition. If a translation unit
241  //   contains one or more tentative definitions for an identifier,
242  //   and the translation unit contains no external definition for
243  //   that identifier, then the behavior is exactly as if the
244  //   translation unit contains a file scope declaration of that
245  //   identifier, with the composite type as of the end of the
246  //   translation unit, with an initializer equal to 0.
247  for (llvm::DenseMap<DeclarationName, VarDecl *>::iterator
248         D = TentativeDefinitions.begin(),
249         DEnd = TentativeDefinitions.end();
250       D != DEnd; ++D) {
251    VarDecl *VD = D->second;
252
253    if (VD->isInvalidDecl() || !VD->isTentativeDefinition(Context))
254      continue;
255
256    if (const IncompleteArrayType *ArrayT
257        = Context.getAsIncompleteArrayType(VD->getType())) {
258      if (RequireCompleteType(VD->getLocation(),
259                              ArrayT->getElementType(),
260                              diag::err_tentative_def_incomplete_type_arr))
261        VD->setInvalidDecl();
262      else {
263        // Set the length of the array to 1 (C99 6.9.2p5).
264        Diag(VD->getLocation(),  diag::warn_tentative_incomplete_array);
265        llvm::APInt One(Context.getTypeSize(Context.getSizeType()),
266                        true);
267        QualType T
268          = Context.getConstantArrayType(ArrayT->getElementType(),
269                                         One, ArrayType::Normal, 0);
270        VD->setType(T);
271      }
272    } else if (RequireCompleteType(VD->getLocation(), VD->getType(),
273                                   diag::err_tentative_def_incomplete_type))
274      VD->setInvalidDecl();
275
276    // Notify the consumer that we've completed a tentative definition.
277    if (!VD->isInvalidDecl())
278      Consumer.CompleteTentativeDefinition(VD);
279
280  }
281}
282
283
284//===----------------------------------------------------------------------===//
285// Helper functions.
286//===----------------------------------------------------------------------===//
287
288/// getCurFunctionDecl - If inside of a function body, this returns a pointer
289/// to the function decl for the function being parsed.  If we're currently
290/// in a 'block', this returns the containing context.
291FunctionDecl *Sema::getCurFunctionDecl() {
292  DeclContext *DC = CurContext;
293  while (isa<BlockDecl>(DC))
294    DC = DC->getParent();
295  return dyn_cast<FunctionDecl>(DC);
296}
297
298ObjCMethodDecl *Sema::getCurMethodDecl() {
299  DeclContext *DC = CurContext;
300  while (isa<BlockDecl>(DC))
301    DC = DC->getParent();
302  return dyn_cast<ObjCMethodDecl>(DC);
303}
304
305NamedDecl *Sema::getCurFunctionOrMethodDecl() {
306  DeclContext *DC = CurContext;
307  while (isa<BlockDecl>(DC))
308    DC = DC->getParent();
309  if (isa<ObjCMethodDecl>(DC) || isa<FunctionDecl>(DC))
310    return cast<NamedDecl>(DC);
311  return 0;
312}
313
314Sema::SemaDiagnosticBuilder::~SemaDiagnosticBuilder() {
315  this->Emit();
316
317  // If this is not a note, and we're in a template instantiation
318  // that is different from the last template instantiation where
319  // we emitted an error, print a template instantiation
320  // backtrace.
321  if (!SemaRef.Diags.isBuiltinNote(DiagID) &&
322      !SemaRef.ActiveTemplateInstantiations.empty() &&
323      SemaRef.ActiveTemplateInstantiations.back()
324        != SemaRef.LastTemplateInstantiationErrorContext) {
325    SemaRef.PrintInstantiationStack();
326    SemaRef.LastTemplateInstantiationErrorContext
327      = SemaRef.ActiveTemplateInstantiations.back();
328  }
329}
330