LLVM  6.0.0svn
Options.h
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1 //===- llvm/Support/Options.h - Debug options support -----------*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 /// \file
10 /// This file declares helper objects for defining debug options that can be
11 /// configured via the command line. The new API currently builds on the cl::opt
12 /// API, but does not require the use of static globals.
13 ///
14 /// With this API options are registered during initialization. For passes, this
15 /// happens during pass initialization. Passes with options will call a static
16 /// registerOptions method during initialization that registers options with the
17 /// OptionRegistry. An example implementation of registerOptions is:
18 ///
19 /// static void registerOptions() {
20 /// OptionRegistry::registerOption<bool, Scalarizer,
21 /// &Scalarizer::ScalarizeLoadStore>(
22 /// "scalarize-load-store",
23 /// "Allow the scalarizer pass to scalarize loads and store", false);
24 /// }
25 ///
26 /// When reading data for options the interface is via the LLVMContext. Option
27 /// data for passes should be read from the context during doInitialization. An
28 /// example of reading the above option would be:
29 ///
30 /// ScalarizeLoadStore =
31 /// M.getContext().getOption<bool,
32 /// Scalarizer,
33 /// &Scalarizer::ScalarizeLoadStore>();
34 ///
35 //===----------------------------------------------------------------------===//
36 
37 #ifndef LLVM_SUPPORT_OPTIONS_H
38 #define LLVM_SUPPORT_OPTIONS_H
39 
40 #include "llvm/ADT/DenseMap.h"
42 
43 namespace llvm {
44 
45 namespace detail {
46 
47 // Options are keyed of the unique address of a static character synthesized
48 // based on template arguments.
49 template <typename ValT, typename Base, ValT(Base::*Mem)> class OptionKey {
50 public:
51  static char ID;
52 };
53 
54 template <typename ValT, typename Base, ValT(Base::*Mem)>
56 
57 } // namespace detail
58 
59 /// \brief Singleton class used to register debug options.
60 ///
61 /// The OptionRegistry is responsible for managing lifetimes of the options and
62 /// provides interfaces for option registration and reading values from options.
63 /// This object is a singleton, only one instance should ever exist so that all
64 /// options are registered in the same place.
66 private:
68 
69  /// \brief Adds a cl::Option to the registry.
70  ///
71  /// \param Key unique key for option
72  /// \param O option to map to \p Key
73  ///
74  /// Allocated cl::Options are owned by the OptionRegistry and are deallocated
75  /// on destruction or removal
76  void addOption(void *Key, cl::Option *O);
77 
78 public:
79  ~OptionRegistry();
81 
82  /// \brief Returns a reference to the singleton instance.
83  static OptionRegistry &instance();
84 
85  /// \brief Registers an option with the OptionRegistry singleton.
86  ///
87  /// \tparam ValT type of the option's data
88  /// \tparam Base class used to key the option
89  /// \tparam Mem member of \p Base used for keying the option
90  ///
91  /// Options are keyed off the template parameters to generate unique static
92  /// characters. The template parameters are (1) the type of the data the
93  /// option stores (\p ValT), the class that will read the option (\p Base),
94  /// and the member that the class will store the data into (\p Mem).
95  template <typename ValT, typename Base, ValT(Base::*Mem)>
96  static void registerOption(StringRef ArgStr, StringRef Desc,
97  const ValT &InitValue) {
98  cl::opt<ValT> *Option = new cl::opt<ValT>(ArgStr, cl::desc(Desc),
99  cl::Hidden, cl::init(InitValue));
100  instance().addOption(&detail::OptionKey<ValT, Base, Mem>::ID, Option);
101  }
102 
103  /// \brief Returns the value of the option.
104  ///
105  /// \tparam ValT type of the option's data
106  /// \tparam Base class used to key the option
107  /// \tparam Mem member of \p Base used for keying the option
108  ///
109  /// Reads option values based on the key generated by the template parameters.
110  /// Keying for get() is the same as keying for registerOption.
111  template <typename ValT, typename Base, ValT(Base::*Mem)> ValT get() const {
112  auto It = Options.find(&detail::OptionKey<ValT, Base, Mem>::ID);
113  assert(It != Options.end() && "Option not in OptionRegistry");
114  return *(cl::opt<ValT> *)It->second;
115  }
116 };
117 
118 } // namespace llvm
119 
120 #endif
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
Key
PAL metadata keys.
initializer< Ty > init(const Ty &Val)
Definition: CommandLine.h:406
static char ID
Definition: Options.h:51
Singleton class used to register debug options.
Definition: Options.h:65
static void registerOption(StringRef ArgStr, StringRef Desc, const ValT &InitValue)
Registers an option with the OptionRegistry singleton.
Definition: Options.h:96
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:49