示例#1
0
void WhileStmt::copyShare(const WhileStmt& ref,
                          SymbolMap*       mapRef,
                          bool             internal)
{
  SymbolMap  localMap;
  SymbolMap* map       = (mapRef != 0) ? mapRef : &localMap;
  Expr*      condExpr  = ref.condExprGet();

  astloc            = ref.astloc;
  blockTag          = ref.blockTag;

  mBreakLabel       = ref.mBreakLabel;
  mContinueLabel    = ref.mContinueLabel;
  mOrderIndependent = ref.mOrderIndependent;

  if (condExpr != 0)
    mCondExpr = condExpr->copy(map, true);

  for_alist(expr, ref.body)
    insertAtTail(expr->copy(map, true));

  if (internal == false)
    update_symbols(this, map);
}
示例#2
0
/*
 * Attempts to replace iteration over simple anonymous ranges with calls to
 * direct iterators that take low, high and stride as arguments. This is to
 * avoid the cost of constructing ranges, and if the stride is known at compile
 * time, provide a more optimized iterator that uses "<, <=, >, or >=" as the
 * relational operator.
 *
 * This is only meant to replace anonymous range iteration for "simple" ranges.
 * Simple means it's a range of the form "low..high", "low..high by stride", or
 * "low..#count". Anything more complex is ignored with the thinking that this
 * should optimize the most common range iterators, but it could be expanded to
 * handle more cases.
 *
 * An alternative is to update scalar replacement of aggregates to work on
 * ranges, which should be able to achieve similar results as this optimization
 * while handling all ranges, including non-anonymous ranges.
 *
 * This function will optimize things like:
 * - "for i in 1..10"
 * - "for i in 1..10+1"
 * - "var lo=1, hi=10;for i in lo..hi"
 * - "for i in 1..10 by 2"
 * - "for i in 1..#10"
 * - "for (i, j) in zip(1..10 by 2, 1..10 by -2)"
 * - "for (i, j) in zip(A, 1..10 by 2)" // will optimize range iter still
 * - "coforall i in 1..10 by 2"         // works for coforalls as well
 *
 * Will not optimize ranges like:
 * - "for in in (1..)"             // doesn't handle unbounded ranges
 * - "for i in 1..10 by 2 by 2"    // doesn't handle more than one by operator
 * - "for i in 1..10 align 2"      // doesn't handle align operator
 * - "for i in (1..10)#2"          // doesn't handle bounded counted ranges
 * - "for i in 1..#10 by 2"        // doesn't handle strided and counted ranges
 * - "var r = 1..10"; for i in r"  // not an anonymous range
 * - "forall i in 1..10"           // doesn't get applied to foralls
 *
 * Note that this function is pretty fragile because it relies on names of
 * functions/iterators as well as the arguments and order of those
 * functions/iterators but there's not really a way around it this early in
 * compilation. If the iterator can't be replaced, it is left unchanged.
 */
static void tryToReplaceWithDirectRangeIterator(Expr* iteratorExpr)
{
  if (CallExpr* call = toCallExpr(iteratorExpr))
  {
    CallExpr* range = NULL;
    Expr* stride = NULL;
    Expr* count = NULL;
    // grab the stride if we have a strided range
    if (call->isNamed("chpl_by"))
    {
      range = toCallExpr(call->get(1)->copy());
      stride = toExpr(call->get(2)->copy());
    }
    // or grab the count if we have a counted range and set unit stride
    else if (call->isNamed("#"))
    {
      range = toCallExpr(call->get(1)->copy());
      count = toExpr(call->get(2)->copy());
      stride = new SymExpr(new_IntSymbol(1));
    }
    // or assume the call is the range (checked below) and set unit stride
    else
    {
      range = call;
      stride = new SymExpr(new_IntSymbol(1));
    }

    //
    // see if we're looking at a range builder. The builder is iteratable since
    // range has these() iterators
    //

    // replace fully bounded (and possibly strided range) with a direct range
    // iter. e.g. replace:
    //
    //   `low..high by stride`
    //
    // with:
    //
    // `chpl_direct_range_iter(low, high, stride)`
    if (range && range->isNamed("chpl_build_bounded_range"))
    {
      // replace the range construction with a direct range iterator
      Expr* low = range->get(1)->copy();
      Expr* high = range->get(2)->copy();
      iteratorExpr->replace(new CallExpr("chpl_direct_range_iter", low, high, stride));
    }

    // replace a counted, low bounded range with unit stride with an equivalent
    // direct range iter. e.g. replace:
    //
    //   `low..#count` (which is equivalent to `low..low+count-1`)
    //
    // with:
    //
    //   `chpl_direct_range_iter(low, low+count-1, 1)`
    else if (count && range && range->isNamed("chpl_build_low_bounded_range"))
    {
      Expr* low = range->get(1)->copy();
      Expr* high = new CallExpr("-", new CallExpr("+", low->copy(), count), new_IntSymbol(1));
      iteratorExpr->replace(new CallExpr("chpl_direct_range_iter", low, high, stride));
    }
  }
}
示例#3
0
BlockStmt* ForLoop::buildForLoop(Expr*      indices,
                                 Expr*      iteratorExpr,
                                 BlockStmt* body,
                                 bool       coforall,
                                 bool       zippered)
{
  VarSymbol*   index         = newTemp("_indexOfInterest");
  VarSymbol*   iterator      = newTemp("_iterator");
  CallExpr*    iterInit      = 0;
  CallExpr*    iterMove      = 0;
  ForLoop*     loop          = new ForLoop(index, iterator, body, zippered);
  LabelSymbol* continueLabel = new LabelSymbol("_continueLabel");
  LabelSymbol* breakLabel    = new LabelSymbol("_breakLabel");
  BlockStmt*   retval        = new BlockStmt();

  iterator->addFlag(FLAG_EXPR_TEMP);

  // Unzippered loop, treat all objects (including tuples) the same
  if (zippered == false) {
    iterInit = new CallExpr(PRIM_MOVE, iterator, new CallExpr("_getIterator",    iteratorExpr));
    // try to optimize anonymous range iteration
    tryToReplaceWithDirectRangeIterator(iteratorExpr);
  }
  // Zippered loop: Expand args to a tuple with an iterator for each element.
  else {
    CallExpr* zipExpr = toCallExpr(iteratorExpr);
    if (zipExpr && zipExpr->isPrimitive(PRIM_ZIP)) {
      // The PRIM_ZIP indicates this is a new-style zip() AST.
      // Expand arguments to a tuple with appropriate iterators for each value.
      //
      // Specifically, change:
      //    zip(a, b, c,  ...)
      // into the tuple:
      //    (_getIterator(a), _getIterator(b), _getIterator(c), ...)
      //
      // (ultimately, we will probably want to make this style of
      // rewrite into a utility function for the other get*Zip
      // functions as we convert parallel loops over to use PRIM_ZIP).
      //
      zipExpr->primitive = NULL;   // remove the primitive

      // If there's just one argument...
      if (zipExpr->argList.length == 1) {
        Expr* zipArg = zipExpr->argList.only();
        CallExpr* zipArgCall = toCallExpr(zipArg);

        // ...and it is a tuple expansion '(...t)' then remove the
        // tuple expansion primitive and simply pass the tuple itself
        // to _getIteratorZip().  This will not require any more
        // tuples than the user introduced themselves.
        //
        if (zipArgCall && zipArgCall->isPrimitive(PRIM_TUPLE_EXPAND)) {
          zipExpr->baseExpr = new UnresolvedSymExpr("_getIteratorZip");
          Expr* tupleArg = zipArgCall->argList.only();
          tupleArg->remove();
          zipArgCall->replace(tupleArg);
        } else {
          // ...otherwise, make the expression into a _getIterator()
          // call
          zipExpr->baseExpr = new UnresolvedSymExpr("_getIterator");
          // try to optimize anonymous range iteration
          tryToReplaceWithDirectRangeIterator(zipArg);
        }
      } else {
        //
        // Otherwise, if there's more than one argument, build up the
        // tuple by applying _getIterator() to each element.
        //
        zipExpr->baseExpr = new UnresolvedSymExpr("_build_tuple");
        Expr* arg = zipExpr->argList.first();
        while (arg) {
          Expr* next = arg->next;
          Expr* argCopy = arg->copy();
          arg->replace(new CallExpr("_getIterator", argCopy));
          // try to optimize anonymous range iteration
          tryToReplaceWithDirectRangeIterator(argCopy);
          arg = next;
        }
      }
      iterInit = new CallExpr(PRIM_MOVE, iterator, zipExpr);
      assert(zipExpr == iteratorExpr);
    } else {
      //
      // This is an old-style zippered loop so handle it in the old style
      //
      iterInit = new CallExpr(PRIM_MOVE, iterator,
                              new CallExpr("_getIteratorZip", iteratorExpr));

      // try to optimize anonymous range iteration
      if (CallExpr* call = toCallExpr(iteratorExpr))
        if (call->isNamed("_build_tuple"))
          for_actuals(actual, call)
            tryToReplaceWithDirectRangeIterator(actual);
    }
  }

  index->addFlag(FLAG_INDEX_OF_INTEREST);

  iterMove = new CallExpr(PRIM_MOVE, index, new CallExpr("iteratorIndex", iterator));

  if (indices == 0)
    indices = new UnresolvedSymExpr("chpl__elidedIdx");

  checkIndices(indices);

  destructureIndices(loop, indices, new SymExpr(index), coforall);

  if (coforall)
    index->addFlag(FLAG_COFORALL_INDEX_VAR);

  loop->mContinueLabel = continueLabel;
  loop->mBreakLabel    = breakLabel;

  loop->insertAtTail(new DefExpr(continueLabel));

  retval->insertAtTail(new DefExpr(index));
  retval->insertAtTail(new DefExpr(iterator));

  retval->insertAtTail(iterInit);
  retval->insertAtTail(new BlockStmt(iterMove, BLOCK_TYPE));

  retval->insertAtTail(loop);

  retval->insertAtTail(new DefExpr(breakLabel));
  retval->insertAtTail(new CallExpr("_freeIterator", iterator));

  return retval;
}