1 files changed, 129 insertions, 0 deletions
diff --git a/js/src/jit/Safepoints.h b/js/src/jit/Safepoints.h
new file mode 100644
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+++ b/js/src/jit/Safepoints.h
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+/* -*- 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/. */
+
+#ifndef jit_Safepoints_h
+#define jit_Safepoints_h
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include "jit/BitSet.h"
+#include "jit/CompactBuffer.h"
+#include "jit/RegisterSets.h"
+
+namespace js {
+namespace jit {
+
+class CodeLocationLabel;
+class IonScript;
+class SafepointIndex;
+struct SafepointSlotEntry;
+class TempAllocator;
+
+class LAllocation;
+class LSafepoint;
+
+static const uint32_t INVALID_SAFEPOINT_OFFSET = uint32_t(-1);
+
+class SafepointWriter {
+  CompactBufferWriter stream_;
+  BitSet localSlots_;
+  BitSet argumentSlots_;
+
+ public:
+  explicit SafepointWriter(uint32_t localSlotsSize, uint32_t argumentsSize);
+  [[nodiscard]] bool init(TempAllocator& alloc);
+
+ private:
+  // A safepoint entry is written in the order these functions appear.
+  uint32_t startEntry();
+
+  void writeOsiCallPointOffset(uint32_t osiPointOffset);
+  void writeGcRegs(LSafepoint* safepoint);
+  void writeGcSlots(LSafepoint* safepoint);
+
+  void writeSlotsOrElementsSlots(LSafepoint* safepoint);
+
+#ifdef JS_PUNBOX64
+  void writeValueSlots(LSafepoint* safepoint);
+#else
+  void writeNunboxParts(LSafepoint* safepoint);
+#endif
+
+  void endEntry();
+
+ public:
+  void encode(LSafepoint* safepoint);
+
+  size_t size() const { return stream_.length(); }
+  const uint8_t* buffer() const { return stream_.buffer(); }
+  bool oom() const { return stream_.oom(); }
+};
+
+class SafepointReader {
+  CompactBufferReader stream_;
+  uint32_t localSlots_;
+  uint32_t argumentSlots_;
+  uint32_t currentSlotChunk_;
+  bool currentSlotsAreStack_;
+  uint32_t nextSlotChunkNumber_;
+  uint32_t osiCallPointOffset_;
+  GeneralRegisterSet gcSpills_;
+  GeneralRegisterSet valueSpills_;
+  GeneralRegisterSet slotsOrElementsSpills_;
+  GeneralRegisterSet allGprSpills_;
+  FloatRegisterSet allFloatSpills_;
+  uint32_t nunboxSlotsRemaining_;
+  uint32_t slotsOrElementsSlotsRemaining_;
+
+ private:
+  void advanceFromGcRegs();
+  void advanceFromGcSlots();
+  void advanceFromNunboxOrValueSlots();
+  [[nodiscard]] bool getSlotFromBitmap(SafepointSlotEntry* entry);
+
+ public:
+  SafepointReader(IonScript* script, const SafepointIndex* si);
+
+  static CodeLocationLabel InvalidationPatchPoint(IonScript* script,
+                                                  const SafepointIndex* si);
+
+  uint32_t osiCallPointOffset() const { return osiCallPointOffset_; }
+  LiveGeneralRegisterSet gcSpills() const {
+    return LiveGeneralRegisterSet(gcSpills_);
+  }
+  LiveGeneralRegisterSet slotsOrElementsSpills() const {
+    return LiveGeneralRegisterSet(slotsOrElementsSpills_);
+  }
+  LiveGeneralRegisterSet valueSpills() const {
+    return LiveGeneralRegisterSet(valueSpills_);
+  }
+  LiveGeneralRegisterSet allGprSpills() const {
+    return LiveGeneralRegisterSet(allGprSpills_);
+  }
+  LiveFloatRegisterSet allFloatSpills() const {
+    return LiveFloatRegisterSet(allFloatSpills_);
+  }
+  uint32_t osiReturnPointOffset() const;
+
+  // Returns true if a slot was read, false if there are no more slots.
+  [[nodiscard]] bool getGcSlot(SafepointSlotEntry* entry);
+
+  // Returns true if a slot was read, false if there are no more value slots.
+  [[nodiscard]] bool getValueSlot(SafepointSlotEntry* entry);
+
+  // Returns true if a nunbox slot was read, false if there are no more
+  // nunbox slots.
+  [[nodiscard]] bool getNunboxSlot(LAllocation* type, LAllocation* payload);
+
+  // Returns true if a slot was read, false if there are no more slots.
+  [[nodiscard]] bool getSlotsOrElementsSlot(SafepointSlotEntry* entry);
+};
+
+}  // namespace jit
+}  // namespace js
+
+#endif /* jit_Safepoints_h */