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llvm-mirror/include/llvm/IR/OptBisect.h
Andrew Kaylor 653d361880 Re-commit optimization bisect support (r267022) without new pass manager support.
The original commit was reverted because of a buildbot problem with LazyCallGraph::SCC handling (not related to the OptBisect handling).

Differential Revision: http://reviews.llvm.org/D19172

llvm-svn: 267231
2016-04-22 22:06:11 +00:00

82 lines
3.2 KiB
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//===----------- llvm/IR/OptBisect.h - LLVM Bisect support -------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// This file declares the interface for bisecting optimizations.
///
//===----------------------------------------------------------------------===//
#ifndef LLVM_IR_OPTBISECT_H
#define LLVM_IR_OPTBISECT_H
namespace llvm {
class Pass;
class StringRef;
class Twine;
/// 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:
/// \brief Default constructor, initializes the OptBisect state based on the
/// -opt-bisect-limit command line argument.
///
/// By default, bisection is disabled.
///
/// Clients should not instantiate this class directly. All access should go
/// through LLVMContext.
OptBisect();
/// Checks the bisect limit to determine if the specified pass should run.
///
/// This function will immediate return true if bisection is disabled. If the
/// bisect limit is set to -1, the function will print a message describing
/// the pass and the bisect number assigned to it and return true. Otherwise,
/// the function will print 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 exceded or false if it has.
///
/// Most passes should not call this routine directly. Instead, it is called
/// through a helper routine provided by the pass base class. For instance,
/// function passes should call FunctionPass::skipFunction().
template <class UnitT>
bool shouldRunPass(const Pass *P, const UnitT &U);
/// Checks the bisect limit to determine if the optimization described by the
/// /p Desc argument should run.
///
/// This function will immediate return true if bisection is disabled. If the
/// bisect limit is set to -1, the function will print a message with the
/// bisect number assigned to the optimization along with the /p Desc
/// description and return true. Otherwise, the function will print a message
/// with the bisect number assigned to the optimization and indicating whether
/// or not the pass will be run and return true if the bisect limit has not
/// yet been exceded or false if it has.
///
/// Passes may call this function to provide more fine grained control over
/// individual optimizations performed by the pass. Passes which cannot be
/// skipped entirely (such as non-optional code generation passes) may still
/// call this function to control whether or not individual optional
/// transformations are performed.
bool shouldRunCase(const Twine &Desc);
private:
bool checkPass(const StringRef PassName, const StringRef TargetDesc);
bool BisectEnabled = false;
unsigned LastBisectNum = 0;
};
} // end namespace llvm
#endif // LLVM_IR_OPTBISECT_H