1 files changed, 111 insertions, 0 deletions
diff --git a/js/src/frontend/BytecodeControlStructures.cpp b/js/src/frontend/BytecodeControlStructures.cpp
new file mode 100644
index 0000000000..401e27d8b2
--- /dev/null
+++ b/js/src/frontend/BytecodeControlStructures.cpp
@@ -0,0 +1,111 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "frontend/BytecodeControlStructures.h"
+
+#include "frontend/BytecodeEmitter.h"  // BytecodeEmitter
+#include "frontend/EmitterScope.h"     // EmitterScope
+#include "vm/Opcodes.h"                // JSOp
+
+using namespace js;
+using namespace js::frontend;
+
+using mozilla::Maybe;
+
+NestableControl::NestableControl(BytecodeEmitter* bce, StatementKind kind)
+    : Nestable<NestableControl>(&bce->innermostNestableControl),
+      kind_(kind),
+      emitterScope_(bce->innermostEmitterScopeNoCheck()) {}
+
+BreakableControl::BreakableControl(BytecodeEmitter* bce, StatementKind kind)
+    : NestableControl(bce, kind) {
+  MOZ_ASSERT(is<BreakableControl>());
+}
+
+bool BreakableControl::patchBreaks(BytecodeEmitter* bce) {
+  return bce->emitJumpTargetAndPatch(breaks);
+}
+
+LabelControl::LabelControl(BytecodeEmitter* bce, const ParserAtom* label,
+                           BytecodeOffset startOffset)
+    : BreakableControl(bce, StatementKind::Label),
+      label_(label),
+      startOffset_(startOffset) {}
+
+LoopControl::LoopControl(BytecodeEmitter* bce, StatementKind loopKind)
+    : BreakableControl(bce, loopKind), tdzCache_(bce) {
+  MOZ_ASSERT(is<LoopControl>());
+
+  LoopControl* enclosingLoop = findNearest<LoopControl>(enclosing());
+
+  stackDepth_ = bce->bytecodeSection().stackDepth();
+  loopDepth_ = enclosingLoop ? enclosingLoop->loopDepth_ + 1 : 1;
+}
+
+bool LoopControl::emitContinueTarget(BytecodeEmitter* bce) {
+  // Note: this is always called after emitting the loop body so we must have
+  // emitted all 'continues' by now.
+  return bce->emitJumpTargetAndPatch(continues);
+}
+
+bool LoopControl::emitLoopHead(BytecodeEmitter* bce,
+                               const Maybe<uint32_t>& nextPos) {
+  // Insert a Nop if needed to ensure the script does not start with a
+  // JSOp::LoopHead. This avoids JIT issues with prologue code + try notes
+  // or OSR. See bug 1602390 and bug 1602681.
+  if (bce->bytecodeSection().offset().toUint32() == 0) {
+    if (!bce->emit1(JSOp::Nop)) {
+      return false;
+    }
+  }
+
+  if (nextPos) {
+    if (!bce->updateSourceCoordNotes(*nextPos)) {
+      return false;
+    }
+  }
+
+  MOZ_ASSERT(loopDepth_ > 0);
+
+  head_ = {bce->bytecodeSection().offset()};
+
+  BytecodeOffset off;
+  if (!bce->emitJumpTargetOp(JSOp::LoopHead, &off)) {
+    return false;
+  }
+  SetLoopHeadDepthHint(bce->bytecodeSection().code(off), loopDepth_);
+
+  return true;
+}
+
+bool LoopControl::emitLoopEnd(BytecodeEmitter* bce, JSOp op,
+                              TryNoteKind tryNoteKind) {
+  JumpList jump;
+  if (!bce->emitJumpNoFallthrough(op, &jump)) {
+    return false;
+  }
+  bce->patchJumpsToTarget(jump, head_);
+
+  // Create a fallthrough for closing iterators, and as a target for break
+  // statements.
+  JumpTarget breakTarget;
+  if (!bce->emitJumpTarget(&breakTarget)) {
+    return false;
+  }
+  if (!patchBreaks(bce)) {
+    return false;
+  }
+  if (!bce->addTryNote(tryNoteKind, bce->bytecodeSection().stackDepth(),
+                       headOffset(), breakTarget.offset)) {
+    return false;
+  }
+  return true;
+}
+
+TryFinallyControl::TryFinallyControl(BytecodeEmitter* bce, StatementKind kind)
+    : NestableControl(bce, kind), emittingSubroutine_(false) {
+  MOZ_ASSERT(is<TryFinallyControl>());
+}