Sema.cpp revision 95d6c95238d03080803549be81139f03a098016e 
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"
22using namespace clang;
23
24/// ConvertQualTypeToStringFn - This function is used to pretty print the
25/// specified QualType as a string in diagnostics.
26static 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
98static 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
109void 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
178Sema::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.
200void 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
226void Sema::DeleteExpr(ExprTy *E) {
227  if (E) static_cast<Expr*>(E)->Destroy(Context);
228}
229void 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.
236void 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.
295FunctionDecl *Sema::getCurFunctionDecl() {
296  DeclContext *DC = CurContext;
297  while (isa<BlockDecl>(DC))
298    DC = DC->getParent();
299  return dyn_cast<FunctionDecl>(DC);
300}
301
302ObjCMethodDecl *Sema::getCurMethodDecl() {
303  DeclContext *DC = CurContext;
304  while (isa<BlockDecl>(DC))
305    DC = DC->getParent();
306  return dyn_cast<ObjCMethodDecl>(DC);
307}
308
309NamedDecl *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
318Sema::SemaDiagnosticBuilder::~SemaDiagnosticBuilder() {
319  if (!this->Emit())
320    return;
321
322  // If this is not a note, and we're in a template instantiation
323  // that is different from the last template instantiation where
324  // we emitted an error, print a template instantiation
325  // backtrace.
326  if (!SemaRef.Diags.isBuiltinNote(DiagID) &&
327      !SemaRef.ActiveTemplateInstantiations.empty() &&
328      SemaRef.ActiveTemplateInstantiations.back()
329        != SemaRef.LastTemplateInstantiationErrorContext) {
330    SemaRef.PrintInstantiationStack();
331    SemaRef.LastTemplateInstantiationErrorContext
332      = SemaRef.ActiveTemplateInstantiations.back();
333  }
334}
335