LLVM  10.0.0svn
LexicalScopes.h
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1 //===- LexicalScopes.cpp - Collecting lexical scope info --------*- 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 file implements LexicalScopes analysis.
10 //
11 // This pass collects lexical scope information and maps machine instructions
12 // to respective lexical scopes.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #ifndef LLVM_CODEGEN_LEXICALSCOPES_H
17 #define LLVM_CODEGEN_LEXICALSCOPES_H
18 
19 #include "llvm/ADT/ArrayRef.h"
20 #include "llvm/ADT/DenseMap.h"
21 #include "llvm/ADT/SmallPtrSet.h"
22 #include "llvm/ADT/SmallVector.h"
24 #include <cassert>
25 #include <unordered_map>
26 #include <utility>
27 
28 namespace llvm {
29 
30 class MachineBasicBlock;
31 class MachineFunction;
32 class MachineInstr;
33 class MDNode;
34 
35 //===----------------------------------------------------------------------===//
36 /// InsnRange - This is used to track range of instructions with identical
37 /// lexical scope.
38 ///
39 using InsnRange = std::pair<const MachineInstr *, const MachineInstr *>;
40 
41 //===----------------------------------------------------------------------===//
42 /// LexicalScope - This class is used to track scope information.
43 ///
44 class LexicalScope {
45 public:
47  bool A)
48  : Parent(P), Desc(D), InlinedAtLocation(I), AbstractScope(A) {
49  assert(D);
50  assert(D->getSubprogram()->getUnit()->getEmissionKind() !=
52  "Don't build lexical scopes for non-debug locations");
53  assert(D->isResolved() && "Expected resolved node");
54  assert((!I || I->isResolved()) && "Expected resolved node");
55  if (Parent)
56  Parent->addChild(this);
57  }
58 
59  // Accessors.
60  LexicalScope *getParent() const { return Parent; }
61  const MDNode *getDesc() const { return Desc; }
62  const DILocation *getInlinedAt() const { return InlinedAtLocation; }
63  const DILocalScope *getScopeNode() const { return Desc; }
64  bool isAbstractScope() const { return AbstractScope; }
66  SmallVectorImpl<InsnRange> &getRanges() { return Ranges; }
67 
68  /// addChild - Add a child scope.
69  void addChild(LexicalScope *S) { Children.push_back(S); }
70 
71  /// openInsnRange - This scope covers instruction range starting from MI.
72  void openInsnRange(const MachineInstr *MI) {
73  if (!FirstInsn)
74  FirstInsn = MI;
75 
76  if (Parent)
77  Parent->openInsnRange(MI);
78  }
79 
80  /// extendInsnRange - Extend the current instruction range covered by
81  /// this scope.
83  assert(FirstInsn && "MI Range is not open!");
84  LastInsn = MI;
85  if (Parent)
86  Parent->extendInsnRange(MI);
87  }
88 
89  /// closeInsnRange - Create a range based on FirstInsn and LastInsn collected
90  /// until now. This is used when a new scope is encountered while walking
91  /// machine instructions.
92  void closeInsnRange(LexicalScope *NewScope = nullptr) {
93  assert(LastInsn && "Last insn missing!");
94  Ranges.push_back(InsnRange(FirstInsn, LastInsn));
95  FirstInsn = nullptr;
96  LastInsn = nullptr;
97  // If Parent dominates NewScope then do not close Parent's instruction
98  // range.
99  if (Parent && (!NewScope || !Parent->dominates(NewScope)))
100  Parent->closeInsnRange(NewScope);
101  }
102 
103  /// dominates - Return true if current scope dominates given lexical scope.
104  bool dominates(const LexicalScope *S) const {
105  if (S == this)
106  return true;
107  if (DFSIn < S->getDFSIn() && DFSOut > S->getDFSOut())
108  return true;
109  return false;
110  }
111 
112  // Depth First Search support to walk and manipulate LexicalScope hierarchy.
113  unsigned getDFSOut() const { return DFSOut; }
114  void setDFSOut(unsigned O) { DFSOut = O; }
115  unsigned getDFSIn() const { return DFSIn; }
116  void setDFSIn(unsigned I) { DFSIn = I; }
117 
118  /// dump - print lexical scope.
119  void dump(unsigned Indent = 0) const;
120 
121 private:
122  LexicalScope *Parent; // Parent to this scope.
123  const DILocalScope *Desc; // Debug info descriptor.
124  const DILocation *InlinedAtLocation; // Location at which this
125  // scope is inlined.
126  bool AbstractScope; // Abstract Scope
127  SmallVector<LexicalScope *, 4> Children; // Scopes defined in scope.
128  // Contents not owned.
130 
131  const MachineInstr *LastInsn = nullptr; // Last instruction of this scope.
132  const MachineInstr *FirstInsn = nullptr; // First instruction of this scope.
133  unsigned DFSIn = 0; // In & Out Depth use to determine scope nesting.
134  unsigned DFSOut = 0;
135 };
136 
137 //===----------------------------------------------------------------------===//
138 /// LexicalScopes - This class provides interface to collect and use lexical
139 /// scoping information from machine instruction.
140 ///
142 public:
143  LexicalScopes() = default;
144 
145  /// initialize - Scan machine function and constuct lexical scope nest, resets
146  /// the instance if necessary.
147  void initialize(const MachineFunction &);
148 
149  /// releaseMemory - release memory.
150  void reset();
151 
152  /// empty - Return true if there is any lexical scope information available.
153  bool empty() { return CurrentFnLexicalScope == nullptr; }
154 
155  /// getCurrentFunctionScope - Return lexical scope for the current function.
157  return CurrentFnLexicalScope;
158  }
159 
160  /// getMachineBasicBlocks - Populate given set using machine basic blocks
161  /// which have machine instructions that belong to lexical scope identified by
162  /// DebugLoc.
163  void getMachineBasicBlocks(const DILocation *DL,
165 
166  /// dominates - Return true if DebugLoc's lexical scope dominates at least one
167  /// machine instruction's lexical scope in a given machine basic block.
168  bool dominates(const DILocation *DL, MachineBasicBlock *MBB);
169 
170  /// findLexicalScope - Find lexical scope, either regular or inlined, for the
171  /// given DebugLoc. Return NULL if not found.
172  LexicalScope *findLexicalScope(const DILocation *DL);
173 
174  /// getAbstractScopesList - Return a reference to list of abstract scopes.
176  return AbstractScopesList;
177  }
178 
179  /// findAbstractScope - Find an abstract scope or return null.
181  auto I = AbstractScopeMap.find(N);
182  return I != AbstractScopeMap.end() ? &I->second : nullptr;
183  }
184 
185  /// findInlinedScope - Find an inlined scope for the given scope/inlined-at.
187  auto I = InlinedLexicalScopeMap.find(std::make_pair(N, IA));
188  return I != InlinedLexicalScopeMap.end() ? &I->second : nullptr;
189  }
190 
191  /// findLexicalScope - Find regular lexical scope or return null.
193  auto I = LexicalScopeMap.find(N);
194  return I != LexicalScopeMap.end() ? &I->second : nullptr;
195  }
196 
197  /// dump - Print data structures to dbgs().
198  void dump() const;
199 
200  /// getOrCreateAbstractScope - Find or create an abstract lexical scope.
201  LexicalScope *getOrCreateAbstractScope(const DILocalScope *Scope);
202 
203 private:
204  /// getOrCreateLexicalScope - Find lexical scope for the given Scope/IA. If
205  /// not available then create new lexical scope.
206  LexicalScope *getOrCreateLexicalScope(const DILocalScope *Scope,
207  const DILocation *IA = nullptr);
208  LexicalScope *getOrCreateLexicalScope(const DILocation *DL) {
209  return DL ? getOrCreateLexicalScope(DL->getScope(), DL->getInlinedAt())
210  : nullptr;
211  }
212 
213  /// getOrCreateRegularScope - Find or create a regular lexical scope.
214  LexicalScope *getOrCreateRegularScope(const DILocalScope *Scope);
215 
216  /// getOrCreateInlinedScope - Find or create an inlined lexical scope.
217  LexicalScope *getOrCreateInlinedScope(const DILocalScope *Scope,
218  const DILocation *InlinedAt);
219 
220  /// extractLexicalScopes - Extract instruction ranges for each lexical scopes
221  /// for the given machine function.
222  void extractLexicalScopes(SmallVectorImpl<InsnRange> &MIRanges,
224  void constructScopeNest(LexicalScope *Scope);
225  void
226  assignInstructionRanges(SmallVectorImpl<InsnRange> &MIRanges,
228 
229  const MachineFunction *MF = nullptr;
230 
231  /// LexicalScopeMap - Tracks the scopes in the current function.
232  // Use an unordered_map to ensure value pointer validity over insertion.
233  std::unordered_map<const DILocalScope *, LexicalScope> LexicalScopeMap;
234 
235  /// InlinedLexicalScopeMap - Tracks inlined function scopes in current
236  /// function.
237  std::unordered_map<std::pair<const DILocalScope *, const DILocation *>,
238  LexicalScope,
240  InlinedLexicalScopeMap;
241 
242  /// AbstractScopeMap - These scopes are not included LexicalScopeMap.
243  // Use an unordered_map to ensure value pointer validity over insertion.
244  std::unordered_map<const DILocalScope *, LexicalScope> AbstractScopeMap;
245 
246  /// AbstractScopesList - Tracks abstract scopes constructed while processing
247  /// a function.
248  SmallVector<LexicalScope *, 4> AbstractScopesList;
249 
250  /// CurrentFnLexicalScope - Top level scope for the current function.
251  ///
252  LexicalScope *CurrentFnLexicalScope = nullptr;
253 };
254 
255 } // end namespace llvm
256 
257 #endif // LLVM_CODEGEN_LEXICALSCOPES_H
void openInsnRange(const MachineInstr *MI)
openInsnRange - This scope covers instruction range starting from MI.
Definition: LexicalScopes.h:72
const DILocalScope * getScopeNode() const
Definition: LexicalScopes.h:63
void extendInsnRange(const MachineInstr *MI)
extendInsnRange - Extend the current instruction range covered by this scope.
Definition: LexicalScopes.h:82
This class represents lattice values for constants.
Definition: AllocatorList.h:23
bool isAbstractScope() const
Definition: LexicalScopes.h:64
void dump(unsigned Indent=0) const
dump - print lexical scope.
const MDNode * getDesc() const
Definition: LexicalScopes.h:61
void push_back(const T &Elt)
Definition: SmallVector.h:211
SmallVectorImpl< InsnRange > & getRanges()
Definition: LexicalScopes.h:66
Metadata node.
Definition: Metadata.h:863
LexicalScope - This class is used to track scope information.
Definition: LexicalScopes.h:44
A scope for locals.
SmallVectorImpl< LexicalScope * > & getChildren()
Definition: LexicalScopes.h:65
LexicalScope * getParent() const
Definition: LexicalScopes.h:60
bool isResolved() const
Check if node is fully resolved.
Definition: Metadata.h:939
void setDFSOut(unsigned O)
This class consists of common code factored out of the SmallVector class to reduce code duplication b...
Definition: APFloat.h:41
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory)...
Definition: APInt.h:32
Debug location.
LexicalScope * findAbstractScope(const DILocalScope *N)
findAbstractScope - Find an abstract scope or return null.
#define P(N)
const DILocation * getInlinedAt() const
Definition: LexicalScopes.h:62
LexicalScope * findLexicalScope(const DILocalScope *N)
findLexicalScope - Find regular lexical scope or return null.
void setDFSIn(unsigned I)
LexicalScope * findInlinedScope(const DILocalScope *N, const DILocation *IA)
findInlinedScope - Find an inlined scope for the given scope/inlined-at.
unsigned getDFSOut() const
unsigned getDFSIn() const
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:837
LexicalScope(LexicalScope *P, const DILocalScope *D, const DILocation *I, bool A)
Definition: LexicalScopes.h:46
static GCRegistry::Add< StatepointGC > D("statepoint-example", "an example strategy for statepoint")
DISubprogram * getSubprogram() const
Get the subprogram for this scope.
static void initialize(TargetLibraryInfoImpl &TLI, const Triple &T, ArrayRef< StringRef > StandardNames)
Initialize the set of available library functions based on the specified target triple.
Representation of each machine instruction.
Definition: MachineInstr.h:64
LexicalScopes - This class provides interface to collect and use lexical scoping information from mac...
void closeInsnRange(LexicalScope *NewScope=nullptr)
closeInsnRange - Create a range based on FirstInsn and LastInsn collected until now.
Definition: LexicalScopes.h:92
#define I(x, y, z)
Definition: MD5.cpp:58
#define N
void addChild(LexicalScope *S)
addChild - Add a child scope.
Definition: LexicalScopes.h:69
ArrayRef< LexicalScope * > getAbstractScopesList() const
getAbstractScopesList - Return a reference to list of abstract scopes.
bool dominates(const LexicalScope *S) const
dominates - Return true if current scope dominates given lexical scope.
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
IRTranslator LLVM IR MI
std::pair< const MachineInstr *, const MachineInstr * > InsnRange
InsnRange - This is used to track range of instructions with identical lexical scope.
Definition: LexicalScopes.h:39
bool empty()
empty - Return true if there is any lexical scope information available.
LexicalScope * getCurrentFunctionScope() const
getCurrentFunctionScope - Return lexical scope for the current function.