CGLoopInfo.h source code [clang_source_code/lib/CodeGen/CGLoopInfo.h]

1	//===---- CGLoopInfo.h - LLVM CodeGen for loop metadata -- C++ ----------===//
2	//
3	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4	// See https://llvm.org/LICENSE.txt for license information.
5	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6	//
7	//===----------------------------------------------------------------------===//
8	//
9	// This is the internal state used for llvm translation for loop statement
10	// metadata.
11	//
12	//===----------------------------------------------------------------------===//
13
14	#ifndef LLVM_CLANG_LIB_CODEGEN_CGLOOPINFO_H
15	#define LLVM_CLANG_LIB_CODEGEN_CGLOOPINFO_H
16
17	#include "llvm/ADT/ArrayRef.h"
18	#include "llvm/ADT/SmallVector.h"
19	#include "llvm/IR/DebugLoc.h"
20	#include "llvm/IR/Value.h"
21	#include "llvm/Support/Compiler.h"
22
23	namespace llvm {
24	class BasicBlock;
25	class Instruction;
26	class MDNode;
27	} // end namespace llvm
28
29	namespace clang {
30	class Attr;
31	class ASTContext;
32	namespace CodeGen {
33
34	/// Attributes that may be specified on loops.
35	struct LoopAttributes {
36	explicit LoopAttributes(bool IsParallel = false);
37	void clear();
38
39	/// Generate llvm.loop.parallel metadata for loads and stores.
40	bool IsParallel;
41
42	/// State of loop vectorization or unrolling.
43	enum LVEnableState { Unspecified, Enable, Disable, Full };
44
45	/// Value for llvm.loop.vectorize.enable metadata.
46	LVEnableState VectorizeEnable;
47
48	/// Value for llvm.loop.unroll.* metadata (enable, disable, or full).
49	LVEnableState UnrollEnable;
50
51	/// Value for llvm.loop.unroll_and_jam.* metadata (enable, disable, or full).
52	LVEnableState UnrollAndJamEnable;
53
54	/// Value for llvm.loop.vectorize.width metadata.
55	unsigned VectorizeWidth;
56
57	/// Value for llvm.loop.interleave.count metadata.
58	unsigned InterleaveCount;
59
60	/// llvm.unroll.
61	unsigned UnrollCount;
62
63	/// llvm.unroll.
64	unsigned UnrollAndJamCount;
65
66	/// Value for llvm.loop.distribute.enable metadata.
67	LVEnableState DistributeEnable;
68
69	/// Value for llvm.loop.pipeline.disable metadata.
70	bool PipelineDisabled;
71
72	/// Value for llvm.loop.pipeline.iicount metadata.
73	unsigned PipelineInitiationInterval;
74	};
75
76	/// Information used when generating a structured loop.
77	class LoopInfo {
78	public:
79	/// Construct a new LoopInfo for the loop with entry Header.
80	LoopInfo(llvm::BasicBlock *Header, const LoopAttributes &Attrs,
81	const llvm::DebugLoc &StartLoc, const llvm::DebugLoc &EndLoc);
82
83	/// Get the loop id metadata for this loop.
84	llvm::MDNode *getLoopID() const { return LoopID; }
85
86	/// Get the header block of this loop.
87	llvm::BasicBlock *getHeader() const { return Header; }
88
89	/// Get the set of attributes active for this loop.
90	const LoopAttributes &getAttributes() const { return Attrs; }
91
92	/// Return this loop's access group or nullptr if it does not have one.
93	llvm::MDNode *getAccessGroup() const { return AccGroup; }
94
95	private:
96	/// Loop ID metadata.
97	llvm::MDNode *LoopID;
98	/// Header block of this loop.
99	llvm::BasicBlock *Header;
100	/// The attributes for this loop.
101	LoopAttributes Attrs;
102	/// The access group for memory accesses parallel to this loop.
103	llvm::MDNode *AccGroup = nullptr;
104	};
105
106	/// A stack of loop information corresponding to loop nesting levels.
107	/// This stack can be used to prepare attributes which are applied when a loop
108	/// is emitted.
109	class LoopInfoStack {
110	LoopInfoStack(const LoopInfoStack &) = delete;
111	void operator=(const LoopInfoStack &) = delete;
112
113	public:
114	LoopInfoStack() {}
115
116	/// Begin a new structured loop. The set of staged attributes will be
117	/// applied to the loop and then cleared.
118	void push(llvm::BasicBlock *Header, const llvm::DebugLoc &StartLoc,
119	const llvm::DebugLoc &EndLoc);
120
121	/// Begin a new structured loop. Stage attributes from the Attrs list.
122	/// The staged attributes are applied to the loop and then cleared.
123	void push(llvm::BasicBlock *Header, clang::ASTContext &Ctx,
124	llvm::ArrayRef<const Attr *> Attrs, const llvm::DebugLoc &StartLoc,
125	const llvm::DebugLoc &EndLoc);
126
127	/// End the current loop.
128	void pop();
129
130	/// Return the top loop id metadata.
131	llvm::MDNode *getCurLoopID() const { return getInfo().getLoopID(); }
132
133	/// Return true if the top loop is parallel.
134	bool getCurLoopParallel() const {
135	return hasInfo() ? getInfo().getAttributes().IsParallel : false;
136	}
137
138	/// Function called by the CodeGenFunction when an instruction is
139	/// created.
140	void InsertHelper(llvm::Instruction *I) const;
141
142	/// Set the next pushed loop as parallel.
143	void setParallel(bool Enable = true) { StagedAttrs.IsParallel = Enable; }
144
145	/// Set the next pushed loop 'vectorize.enable'
146	void setVectorizeEnable(bool Enable = true) {
147	StagedAttrs.VectorizeEnable =
148	Enable ? LoopAttributes::Enable : LoopAttributes::Disable;
149	}
150
151	/// Set the next pushed loop as a distribution candidate.
152	void setDistributeState(bool Enable = true) {
153	StagedAttrs.DistributeEnable =
154	Enable ? LoopAttributes::Enable : LoopAttributes::Disable;
155	}
156
157	/// Set the next pushed loop unroll state.
158	void setUnrollState(const LoopAttributes::LVEnableState &State) {
159	StagedAttrs.UnrollEnable = State;
160	}
161
162	/// Set the next pushed loop unroll_and_jam state.
163	void setUnrollAndJamState(const LoopAttributes::LVEnableState &State) {
164	StagedAttrs.UnrollAndJamEnable = State;
165	}
166
167	/// Set the vectorize width for the next loop pushed.
168	void setVectorizeWidth(unsigned W) { StagedAttrs.VectorizeWidth = W; }
169
170	/// Set the interleave count for the next loop pushed.
171	void setInterleaveCount(unsigned C) { StagedAttrs.InterleaveCount = C; }
172
173	/// Set the unroll count for the next loop pushed.
174	void setUnrollCount(unsigned C) { StagedAttrs.UnrollCount = C; }
175
176	/// \brief Set the unroll count for the next loop pushed.
177	void setUnrollAndJamCount(unsigned C) { StagedAttrs.UnrollAndJamCount = C; }
178
179	/// Set the pipeline disabled state.
180	void setPipelineDisabled(bool S) { StagedAttrs.PipelineDisabled = S; }
181
182	/// Set the pipeline initiation interval.
183	void setPipelineInitiationInterval(unsigned C) {
184	StagedAttrs.PipelineInitiationInterval = C;
185	}
186
187	private:
188	/// Returns true if there is LoopInfo on the stack.
189	bool hasInfo() const { return !Active.empty(); }
190	/// Return the LoopInfo for the current loop. HasInfo should be called
191	/// first to ensure LoopInfo is present.
192	const LoopInfo &getInfo() const { return Active.back(); }
193	/// The set of attributes that will be applied to the next pushed loop.
194	LoopAttributes StagedAttrs;
195	/// Stack of active loops.
196	llvm::SmallVector<LoopInfo, 4> Active;
197	};
198
199	} // end namespace CodeGen
200	} // end namespace clang
201
202	#endif
203