clang/lib/Sema/SemaStmtAttr.cpp

//===--- SemaStmtAttr.cpp - Statement Attribute Handling ------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
//  This file implements stmt-related attribute processing.
//
//===----------------------------------------------------------------------===//

#include "clang/Sema/SemaInternal.h"
#include "clang/AST/ASTContext.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Sema/DelayedDiagnostic.h"
#include "clang/Sema/Lookup.h"
#include "clang/Sema/ScopeInfo.h"
#include "llvm/ADT/StringExtras.h"

using namespace clang;
using namespace sema;

static Attr *handleFallThroughAttr(Sema &S, Stmt *St, const AttributeList &A,
                                   SourceRange Range) {
  if (!isa<NullStmt>(St)) {
    S.Diag(A.getRange().getBegin(), diag::err_fallthrough_attr_wrong_target)
        << St->getLocStart();
    if (isa<SwitchCase>(St)) {
      SourceLocation L = S.getLocForEndOfToken(Range.getEnd());
      S.Diag(L, diag::note_fallthrough_insert_semi_fixit)
          << FixItHint::CreateInsertion(L, ";");
    }
    return nullptr;
  }
  if (S.getCurFunction()->SwitchStack.empty()) {
    S.Diag(A.getRange().getBegin(), diag::err_fallthrough_attr_outside_switch);
    return nullptr;
  }
  return ::new (S.Context) FallThroughAttr(A.getRange(), S.Context,
                                           A.getAttributeSpellingListIndex());
}


static Attr *ProcessStmtAttribute(Sema &S, Stmt *St, const AttributeList &A,
                                  SourceRange Range) {
  switch (A.getKind()) {
  case AttributeList::UnknownAttribute:
    S.Diag(A.getLoc(), A.isDeclspecAttribute() ?
           diag::warn_unhandled_ms_attribute_ignored :
           diag::warn_unknown_attribute_ignored) << A.getName();
    return nullptr;
  case AttributeList::AT_FallThrough:
    return handleFallThroughAttr(S, St, A, Range);
  default:
    // if we're here, then we parsed a known attribute, but didn't recognize
    // it as a statement attribute => it is declaration attribute
    S.Diag(A.getRange().getBegin(), diag::err_attribute_invalid_on_stmt)
        << A.getName() << St->getLocStart();
    return nullptr;
  }
}

StmtResult Sema::ProcessStmtAttributes(Stmt *S, AttributeList *AttrList,
                                       SourceRange Range) {
  SmallVector<const Attr*, 8> Attrs;
  for (const AttributeList* l = AttrList; l; l = l->getNext()) {
    if (Attr *a = ProcessStmtAttribute(*this, S, *l, Range))
      Attrs.push_back(a);
  }

  if (Attrs.empty())
    return S;

  return ActOnAttributedStmt(Range.getBegin(), Attrs, S);
}