1//===---- CGLoopInfo.h - LLVM CodeGen for loop metadata -*- 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//
10// This is the internal state used for llvm translation for loop statement
11// metadata.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef CLANG_CODEGEN_CGLOOPINFO_H
16#define CLANG_CODEGEN_CGLOOPINFO_H
17
18#include "llvm/ADT/DenseMap.h"
19#include "llvm/ADT/SmallVector.h"
20#include "llvm/IR/Value.h"
21#include "llvm/Support/Compiler.h"
22
23namespace llvm {
24class BasicBlock;
25class Instruction;
26class MDNode;
27} // end namespace llvm
28
29namespace clang {
30namespace CodeGen {
31
32/// \brief Attributes that may be specified on loops.
33struct LoopAttributes {
34  explicit LoopAttributes(bool IsParallel = false);
35  void clear();
36
37  /// \brief Generate llvm.loop.parallel metadata for loads and stores.
38  bool IsParallel;
39
40  /// \brief Values of llvm.loop.vectorize.enable metadata.
41  enum LVEnableState { VecUnspecified, VecEnable, VecDisable };
42
43  /// \brief llvm.loop.vectorize.enable
44  LVEnableState VectorizerEnable;
45
46  /// \brief llvm.loop.vectorize.width
47  unsigned VectorizerWidth;
48
49  /// \brief llvm.loop.vectorize.unroll
50  unsigned VectorizerUnroll;
51};
52
53/// \brief Information used when generating a structured loop.
54class LoopInfo {
55public:
56  /// \brief Construct a new LoopInfo for the loop with entry Header.
57  LoopInfo(llvm::BasicBlock *Header, const LoopAttributes &Attrs);
58
59  /// \brief Get the loop id metadata for this loop.
60  llvm::MDNode *getLoopID() const { return LoopID; }
61
62  /// \brief Get the header block of this loop.
63  llvm::BasicBlock *getHeader() const { return Header; }
64
65  /// \brief Get the set of attributes active for this loop.
66  const LoopAttributes &getAttributes() const { return Attrs; }
67
68private:
69  /// \brief Loop ID metadata.
70  llvm::MDNode *LoopID;
71  /// \brief Header block of this loop.
72  llvm::BasicBlock *Header;
73  /// \brief The attributes for this loop.
74  LoopAttributes Attrs;
75};
76
77/// \brief A stack of loop information corresponding to loop nesting levels.
78/// This stack can be used to prepare attributes which are applied when a loop
79/// is emitted.
80class LoopInfoStack {
81  LoopInfoStack(const LoopInfoStack &) LLVM_DELETED_FUNCTION;
82  void operator=(const LoopInfoStack &) LLVM_DELETED_FUNCTION;
83
84public:
85  LoopInfoStack() {}
86
87  /// \brief Begin a new structured loop. The set of staged attributes will be
88  /// applied to the loop and then cleared.
89  void push(llvm::BasicBlock *Header);
90
91  /// \brief End the current loop.
92  void pop();
93
94  /// \brief Return the top loop id metadata.
95  llvm::MDNode *getCurLoopID() const { return getInfo().getLoopID(); }
96
97  /// \brief Return true if the top loop is parallel.
98  bool getCurLoopParallel() const {
99    return hasInfo() ? getInfo().getAttributes().IsParallel : false;
100  }
101
102  /// \brief Function called by the CodeGenFunction when an instruction is
103  /// created.
104  void InsertHelper(llvm::Instruction *I) const;
105
106  /// \brief Set the next pushed loop as parallel.
107  void setParallel(bool Enable = true) { StagedAttrs.IsParallel = Enable; }
108
109  /// \brief Set the next pushed loop 'vectorizer.enable'
110  void setVectorizerEnable(bool Enable = true) {
111    StagedAttrs.VectorizerEnable =
112        Enable ? LoopAttributes::VecEnable : LoopAttributes::VecDisable;
113  }
114
115  /// \brief Set the vectorizer width for the next loop pushed.
116  void setVectorizerWidth(unsigned W) { StagedAttrs.VectorizerWidth = W; }
117
118  /// \brief Set the vectorizer unroll for the next loop pushed.
119  void setVectorizerUnroll(unsigned U) { StagedAttrs.VectorizerUnroll = U; }
120
121private:
122  /// \brief Returns true if there is LoopInfo on the stack.
123  bool hasInfo() const { return !Active.empty(); }
124  /// \brief Return the LoopInfo for the current loop. HasInfo should be called
125  /// first to ensure LoopInfo is present.
126  const LoopInfo &getInfo() const { return Active.back(); }
127  /// \brief The set of attributes that will be applied to the next pushed loop.
128  LoopAttributes StagedAttrs;
129  /// \brief Stack of active loops.
130  llvm::SmallVector<LoopInfo, 4> Active;
131};
132
133} // end namespace CodeGen
134} // end namespace clang
135
136#endif // CLANG_CODEGEN_CGLOOPINFO_H
137