1 files changed, 155 insertions, 0 deletions
diff --git a/js/src/jit/CacheIRReader.h b/js/src/jit/CacheIRReader.h
new file mode 100644
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+++ b/js/src/jit/CacheIRReader.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_CacheIRReader_h
+#define jit_CacheIRReader_h
+
+#include "mozilla/Assertions.h"
+#include "mozilla/Attributes.h"
+
+#include <stdint.h>
+#include "NamespaceImports.h"
+
+#include "jit/CacheIR.h"
+#include "jit/CacheIRWriter.h"
+#include "jit/CompactBuffer.h"
+#include "js/ScalarType.h"
+#include "js/Value.h"
+#include "wasm/WasmValType.h"
+
+enum class JSOp : uint8_t;
+
+namespace js {
+
+enum class UnaryMathFunction : uint8_t;
+
+namespace gc {
+enum class AllocKind : uint8_t;
+}
+
+namespace jit {
+
+class CacheIRStubInfo;
+
+// Helper class for reading CacheIR bytecode.
+class MOZ_RAII CacheIRReader {
+  CompactBufferReader buffer_;
+
+  CacheIRReader(const CacheIRReader&) = delete;
+  CacheIRReader& operator=(const CacheIRReader&) = delete;
+
+ public:
+  CacheIRReader(const uint8_t* start, const uint8_t* end)
+      : buffer_(start, end) {}
+  explicit CacheIRReader(const CacheIRWriter& writer)
+      : CacheIRReader(writer.codeStart(), writer.codeEnd()) {}
+  explicit CacheIRReader(const CacheIRStubInfo* stubInfo);
+
+  bool more() const { return buffer_.more(); }
+
+  CacheOp readOp() { return CacheOp(buffer_.readUnsigned15Bit()); }
+
+  // Skip data not currently used.
+  void skip() { buffer_.readByte(); }
+  void skip(uint32_t skipLength) {
+    if (skipLength > 0) {
+      buffer_.seek(buffer_.currentPosition(), skipLength);
+    }
+  }
+
+  ValOperandId valOperandId() { return ValOperandId(buffer_.readByte()); }
+  ValueTagOperandId valueTagOperandId() {
+    return ValueTagOperandId(buffer_.readByte());
+  }
+
+  IntPtrOperandId intPtrOperandId() {
+    return IntPtrOperandId(buffer_.readByte());
+  }
+
+  ObjOperandId objOperandId() { return ObjOperandId(buffer_.readByte()); }
+  NumberOperandId numberOperandId() {
+    return NumberOperandId(buffer_.readByte());
+  }
+  StringOperandId stringOperandId() {
+    return StringOperandId(buffer_.readByte());
+  }
+
+  SymbolOperandId symbolOperandId() {
+    return SymbolOperandId(buffer_.readByte());
+  }
+
+  BigIntOperandId bigIntOperandId() {
+    return BigIntOperandId(buffer_.readByte());
+  }
+
+  BooleanOperandId booleanOperandId() {
+    return BooleanOperandId(buffer_.readByte());
+  }
+
+  Int32OperandId int32OperandId() { return Int32OperandId(buffer_.readByte()); }
+
+  uint32_t rawOperandId() { return buffer_.readByte(); }
+
+  uint32_t stubOffset() { return buffer_.readByte() * sizeof(uintptr_t); }
+  GuardClassKind guardClassKind() { return GuardClassKind(buffer_.readByte()); }
+  ValueType valueType() { return ValueType(buffer_.readByte()); }
+  wasm::ValType::Kind wasmValType() {
+    return wasm::ValType::Kind(buffer_.readByte());
+  }
+  gc::AllocKind allocKind() { return gc::AllocKind(buffer_.readByte()); }
+  CompletionKind completionKind() { return CompletionKind(buffer_.readByte()); }
+
+  Scalar::Type scalarType() { return Scalar::Type(buffer_.readByte()); }
+  JSWhyMagic whyMagic() { return JSWhyMagic(buffer_.readByte()); }
+  JSOp jsop() { return JSOp(buffer_.readByte()); }
+  int32_t int32Immediate() { return int32_t(buffer_.readFixedUint32_t()); }
+  uint32_t uint32Immediate() { return buffer_.readFixedUint32_t(); }
+  void* pointer() { return buffer_.readRawPointer(); }
+
+  UnaryMathFunction unaryMathFunction() {
+    return UnaryMathFunction(buffer_.readByte());
+  }
+
+  CallFlags callFlags() {
+    // See CacheIRWriter::writeCallFlagsImm()
+    uint8_t encoded = buffer_.readByte();
+    CallFlags::ArgFormat format =
+        CallFlags::ArgFormat(encoded & CallFlags::ArgFormatMask);
+    bool isConstructing = encoded & CallFlags::IsConstructing;
+    bool isSameRealm = encoded & CallFlags::IsSameRealm;
+    bool needsUninitializedThis = encoded & CallFlags::NeedsUninitializedThis;
+    MOZ_ASSERT_IF(needsUninitializedThis, isConstructing);
+    switch (format) {
+      case CallFlags::Unknown:
+        MOZ_CRASH("Unexpected call flags");
+      case CallFlags::Standard:
+        return CallFlags(isConstructing, /*isSpread =*/false, isSameRealm,
+                         needsUninitializedThis);
+      case CallFlags::Spread:
+        return CallFlags(isConstructing, /*isSpread =*/true, isSameRealm,
+                         needsUninitializedThis);
+      default:
+        // The existing non-standard argument formats (FunCall and FunApply)
+        // can't be constructors.
+        MOZ_ASSERT(!isConstructing);
+        return CallFlags(format);
+    }
+  }
+
+  uint8_t readByte() { return buffer_.readByte(); }
+  bool readBool() {
+    uint8_t b = buffer_.readByte();
+    MOZ_ASSERT(b <= 1);
+    return bool(b);
+  }
+
+  const uint8_t* currentPosition() const { return buffer_.currentPosition(); }
+};
+
+}  // namespace jit
+}  // namespace js
+
+#endif /* jit_CacheIRReader_h */