Files
swift-mirror/lib/SILOptimizer/SemanticARC/BorrowScopeOpts.cpp
Michael Gottesman 56664088ec [semantic-arc] Expand out the infrastructure for disabling/enabling specific opts and use that to add new split up semantic-arc tests.
This split will ensure we are testing only what a specific optimization is doing
rather than all together.

NOTE: The way I split up the tests is I first split up each of the tests by
subject area by hand that I thought were specifically testing one pass. Then any
tests where the FileCheck tests started to fail due to us not running the other
passes, I put back a copy in the original semantic-arc-opts.sil to ensure we do
not regress.

Note, the tests that I copied for each of these passes
are originally from semantic-arc-opts.sil. I left them there as well so we could
see all of the opts together. I also only copied the ones that were testing pass
specific functionality.
2020-11-25 19:32:01 -08:00

63 lines
2.2 KiB
C++

//===--- BorrowScopeOpts.cpp ----------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
///
/// \file
///
/// Optimizations that attempt to simplify and or eliminate borrow scopes. Today
/// we only eliminate scopes, but we could also eliminate redundant scopes by
/// converting struct_extract operations to use destructure operations.
///
//===----------------------------------------------------------------------===//
#include "Context.h"
#include "SemanticARCOptVisitor.h"
using namespace swift;
using namespace swift::semanticarc;
bool SemanticARCOptVisitor::visitBeginBorrowInst(BeginBorrowInst *bbi) {
// Quickly check if we are supposed to perform this transformation.
if (!ctx.shouldPerform(ARCTransformKind::RedundantBorrowScopeElimPeephole))
return false;
auto kind = bbi->getOperand().getOwnershipKind();
SmallVector<EndBorrowInst *, 16> endBorrows;
for (auto *op : bbi->getUses()) {
if (!op->isLifetimeEnding()) {
// Make sure that this operand can accept our arguments kind.
if (op->canAcceptKind(kind))
continue;
return false;
}
// Otherwise, this borrow is being consumed. See if our consuming inst is an
// end_borrow. If it isn't, then return false, this scope is
// needed. Otherwise, add the end_borrow to our list of end borrows.
auto *ebi = dyn_cast<EndBorrowInst>(op->getUser());
if (!ebi) {
return false;
}
endBorrows.push_back(ebi);
}
// At this point, we know that the begin_borrow's operand can be
// used as an argument to all non-end borrow uses. Eliminate the
// begin borrow and end borrows.
while (!endBorrows.empty()) {
auto *ebi = endBorrows.pop_back_val();
eraseInstruction(ebi);
}
eraseAndRAUWSingleValueInstruction(bbi, bbi->getOperand());
return true;
}