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thirdparty/capstone/suite/synctools/tablegen/include/llvm/IR/OptBisect.h

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+//===- llvm/IR/OptBisect.h - LLVM Bisect support ----------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file declares the interface for bisecting optimizations.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_IR_OPTBISECT_H
+#define LLVM_IR_OPTBISECT_H
+
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/ManagedStatic.h"
+#include <limits>
+
+namespace llvm {
+
+class Pass;
+
+/// Extensions to this class implement mechanisms to disable passes and
+/// individual optimizations at compile time.
+class OptPassGate {
+public:
+  virtual ~OptPassGate() = default;
+
+  /// IRDescription is a textual description of the IR unit the pass is running
+  /// over.
+  virtual bool shouldRunPass(const Pass *P, StringRef IRDescription) {
+    return true;
+  }
+
+  /// isEnabled() should return true before calling shouldRunPass().
+  virtual bool isEnabled() const { return false; }
+};
+
+/// This class implements a mechanism to disable passes and individual
+/// optimizations at compile time based on a command line option
+/// (-opt-bisect-limit) in order to perform a bisecting search for
+/// optimization-related problems.
+class OptBisect : public OptPassGate {
+public:
+  /// Default constructor. Initializes the state to "disabled". The bisection
+  /// will be enabled by the cl::opt call-back when the command line option
+  /// is processed.
+  /// Clients should not instantiate this class directly.  All access should go
+  /// through LLVMContext.
+  OptBisect() = default;
+
+  virtual ~OptBisect() = default;
+
+  /// Checks the bisect limit to determine if the specified pass should run.
+  ///
+  /// This forwards to checkPass().
+  bool shouldRunPass(const Pass *P, StringRef IRDescription) override;
+
+  /// isEnabled() should return true before calling shouldRunPass().
+  bool isEnabled() const override { return BisectLimit != Disabled; }
+
+  /// Set the new optimization limit and reset the counter. Passing
+  /// OptBisect::Disabled disables the limiting.
+  void setLimit(int Limit) {
+    BisectLimit = Limit;
+    LastBisectNum = 0;
+  }
+
+  /// Checks the bisect limit to determine if the specified pass should run.
+  ///
+  /// If the bisect limit is set to -1, the function prints a message describing
+  /// the pass and the bisect number assigned to it and return true.  Otherwise,
+  /// the function prints a message with the bisect number assigned to the
+  /// pass and indicating whether or not the pass will be run and return true if
+  /// the bisect limit has not yet been exceeded or false if it has.
+  ///
+  /// Most passes should not call this routine directly. Instead, they are
+  /// called through helper routines provided by the pass base classes.  For
+  /// instance, function passes should call FunctionPass::skipFunction().
+  bool checkPass(const StringRef PassName, const StringRef TargetDesc);
+
+  static const int Disabled = std::numeric_limits<int>::max();
+
+private:
+  int BisectLimit = Disabled;
+  int LastBisectNum = 0;
+};
+
+/// Singleton instance of the OptBisect class, so multiple pass managers don't
+/// need to coordinate their uses of OptBisect.
+extern ManagedStatic<OptBisect> OptBisector;
+} // end namespace llvm
+
+#endif // LLVM_IR_OPTBISECT_H