path: root/Sema/SemaDecl.cpp

//===--- SemaDecl.cpp - Semantic Analysis for Declarations ----------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file was developed by Chris Lattner and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file implements semantic analysis for declarations.
//
//===----------------------------------------------------------------------===//

#include "Sema.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Builtins.h"
#include "clang/AST/Decl.h"
#include "clang/AST/Expr.h"
#include "clang/AST/Type.h"
#include "clang/Parse/DeclSpec.h"
#include "clang/Parse/Scope.h"
#include "clang/Lex/IdentifierTable.h"
#include "clang/Basic/LangOptions.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/ADT/SmallSet.h"
using namespace clang;

// C99: 6.7.5p3: Used by ParseDeclarator/ParseField to make sure we have
// a constant expression of type int with a value greater than zero.
bool Sema::VerifyConstantArrayType(const ArrayType *Array,
                                   SourceLocation DeclLoc) { 
  const Expr *Size = Array->getSizeExpr();
  if (Size == 0) return false;  // incomplete type.
  
  if (!Size->getType()->isIntegerType()) {
    Diag(Size->getLocStart(), diag::err_array_size_non_int, 
         Size->getType().getAsString(), Size->getSourceRange());
    return true;
  }

  // Verify that the size of the array is an integer constant expr.
  SourceLocation Loc;
  llvm::APSInt SizeVal(32);
  if (!Size->isIntegerConstantExpr(SizeVal, &Loc)) {
    // FIXME: This emits the diagnostic to enforce 6.7.2.1p8, but the message
    // is wrong.  It is also wrong for static variables.
    // FIXME: This is also wrong for:
    // int sub1(int i, char *pi) { typedef int foo[i];
    // struct bar {foo f1; int f2:3; int f3:4} *p; }
    Diag(DeclLoc, diag::err_typecheck_illegal_vla, Size->getSourceRange());
    return true;
  }
  
  // We have a constant expression with an integer type, now make sure 
  // value greater than zero (C99 6.7.5.2p1).
  
  // FIXME: This check isn't specific to static VLAs, this should be moved
  // elsewhere or replicated.  'int X[-1];' inside a function should emit an
  // error.
  if (SizeVal.isSigned()) {
    llvm::APSInt Zero(SizeVal.getBitWidth());
    Zero.setIsUnsigned(false);
    if (SizeVal < Zero) {
      Diag(DeclLoc, diag::err_typecheck_negative_array_size,
           Size->getSourceRange());
      return true;
    } else if (SizeVal == 0) {
      // GCC accepts zero sized static arrays.
      Diag(DeclLoc, diag::err_typecheck_zero_array_size, 
           Size->getSourceRange());
    }
  }
  return false;
}

Sema::DeclTy *Sema::isTypeName(const IdentifierInfo &II, Scope *S) const {
  return dyn_cast_or_null<TypedefDecl>(II.getFETokenInfo<Decl>());
}

void Sema::PopScope(SourceLocation Loc, Scope *S) {
  for (Scope::decl_iterator I = S->decl_begin(), E = S->decl_end();
       I != E; ++I) {
    Decl *D = static_cast<Decl*>(*I);
    assert(D && "This decl didn't get pushed??");
    IdentifierInfo *II = D->getIdentifier();
    if (!II) continue;
    
    // Unlink this decl from the identifier.  Because the scope contains decls
    // in an unordered collection, and because we have multiple identifier
    // namespaces (e.g. tag, normal, label),the decl may not be the first entry.
    if (II->getFETokenInfo<Decl>() == D) {
      // Normal case, no multiple decls in different namespaces.
      II->setFETokenInfo(D->getNext());
    } else {
      // Scan ahead.  There are only three namespaces in C, so this loop can
      // never execute more than 3 times.
      Decl *SomeDecl = II->getFETokenInfo<Decl>();
      while (SomeDecl->getNext() != D) {
        SomeDecl = SomeDecl->getNext();
        assert(SomeDecl && "Didn't find this decl on its identifier's chain!");
      }
      SomeDecl->setNext(D->getNext());
    }
    
    // This will have to be revisited for C++: there we want to nest stuff in
    // namespace decls etc.  Even for C, we might want a top-level translation
    // unit decl or something.
    if (!CurFunctionDecl)
      continue;

    // Chain this decl to the containing function, it now owns the memory for
    // the decl.
    D->setNext(CurFunctionDecl->getDeclChain());
    CurFunctionDecl->setDeclChain(D);
  }
}

/// LookupScopedDecl - Look up the inner-most declaration in the specified
/// namespace.
Decl *Sema::LookupScopedDecl(IdentifierInfo *II, unsigned NSI,
                             SourceLocation IdLoc, Scope *S) {
  if (II == 0) return 0;
  Decl::IdentifierNamespace NS = (Decl::IdentifierNamespace)NSI;
  
  // Scan up the scope chain looking for a decl that matches this identifier
  // that is in the appropriate namespace.  This search should not take long, as
  // shadowing of names is uncommon, and deep shadowing is extremely uncommon.
  for (Decl *D = II->getFETokenInfo<Decl>(); D; D = D->getNext())
    if (D->getIdentifierNamespace() == NS)