1//===-- llvm/CodeGen/DebugLocEntry.h - Entry in debug_loc list -*- 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#ifndef LLVM_LIB_CODEGEN_ASMPRINTER_DEBUGLOCENTRY_H
10#define LLVM_LIB_CODEGEN_ASMPRINTER_DEBUGLOCENTRY_H
11
12#include "DebugLocStream.h"
13#include "llvm/Config/llvm-config.h"
14#include "llvm/IR/Constants.h"
15#include "llvm/IR/DebugInfo.h"
16#include "llvm/MC/MCSymbol.h"
17#include "llvm/MC/MachineLocation.h"
18#include "llvm/Support/Debug.h"
19
20namespace llvm {
21class AsmPrinter;
22
23/// This struct describes target specific location.
24struct TargetIndexLocation {
25  int Index;
26  int Offset;
27
28  TargetIndexLocation() = default;
29  TargetIndexLocation(unsigned Idx, int64_t Offset)
30      : Index(Idx), Offset(Offset) {}
31
32  bool operator==(const TargetIndexLocation &Other) const {
33    return Index == Other.Index && Offset == Other.Offset;
34  }
35};
36
37/// A single location or constant.
38class DbgValueLoc {
39  /// Any complex address location expression for this DbgValueLoc.
40  const DIExpression *Expression;
41
42  /// Type of entry that this represents.
43  enum EntryType {
44    E_Location,
45    E_Integer,
46    E_ConstantFP,
47    E_ConstantInt,
48    E_TargetIndexLocation
49  };
50  enum EntryType EntryKind;
51
52  /// Either a constant,
53  union {
54    int64_t Int;
55    const ConstantFP *CFP;
56    const ConstantInt *CIP;
57  } Constant;
58
59  union {
60    /// Or a location in the machine frame.
61    MachineLocation Loc;
62    /// Or a location from target specific location.
63    TargetIndexLocation TIL;
64  };
65
66public:
67  DbgValueLoc(const DIExpression *Expr, int64_t i)
68      : Expression(Expr), EntryKind(E_Integer) {
69    Constant.Int = i;
70  }
71  DbgValueLoc(const DIExpression *Expr, const ConstantFP *CFP)
72      : Expression(Expr), EntryKind(E_ConstantFP) {
73    Constant.CFP = CFP;
74  }
75  DbgValueLoc(const DIExpression *Expr, const ConstantInt *CIP)
76      : Expression(Expr), EntryKind(E_ConstantInt) {
77    Constant.CIP = CIP;
78  }
79  DbgValueLoc(const DIExpression *Expr, MachineLocation Loc)
80      : Expression(Expr), EntryKind(E_Location), Loc(Loc) {
81    assert(cast<DIExpression>(Expr)->isValid());
82  }
83  DbgValueLoc(const DIExpression *Expr, TargetIndexLocation Loc)
84      : Expression(Expr), EntryKind(E_TargetIndexLocation), TIL(Loc) {}
85
86  bool isLocation() const { return EntryKind == E_Location; }
87  bool isTargetIndexLocation() const {
88    return EntryKind == E_TargetIndexLocation;
89  }
90  bool isInt() const { return EntryKind == E_Integer; }
91  bool isConstantFP() const { return EntryKind == E_ConstantFP; }
92  bool isConstantInt() const { return EntryKind == E_ConstantInt; }
93  int64_t getInt() const { return Constant.Int; }
94  const ConstantFP *getConstantFP() const { return Constant.CFP; }
95  const ConstantInt *getConstantInt() const { return Constant.CIP; }
96  MachineLocation getLoc() const { return Loc; }
97  TargetIndexLocation getTargetIndexLocation() const { return TIL; }
98  bool isFragment() const { return getExpression()->isFragment(); }
99  bool isEntryVal() const { return getExpression()->isEntryValue(); }
100  const DIExpression *getExpression() const { return Expression; }
101  friend bool operator==(const DbgValueLoc &, const DbgValueLoc &);
102  friend bool operator<(const DbgValueLoc &, const DbgValueLoc &);
103#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
104  LLVM_DUMP_METHOD void dump() const {
105    if (isLocation()) {
106      llvm::dbgs() << "Loc = { reg=" << Loc.getReg() << " ";
107      if (Loc.isIndirect())
108        llvm::dbgs() << "+0";
109      llvm::dbgs() << "} ";
110    } else if (isConstantInt())
111      Constant.CIP->dump();
112    else if (isConstantFP())
113      Constant.CFP->dump();
114    if (Expression)
115      Expression->dump();
116  }
117#endif
118};
119
120/// This struct describes location entries emitted in the .debug_loc
121/// section.
122class DebugLocEntry {
123  /// Begin and end symbols for the address range that this location is valid.
124  const MCSymbol *Begin;
125  const MCSymbol *End;
126
127  /// A nonempty list of locations/constants belonging to this entry,
128  /// sorted by offset.
129  SmallVector<DbgValueLoc, 1> Values;
130
131public:
132  /// Create a location list entry for the range [\p Begin, \p End).
133  ///
134  /// \param Vals One or more values describing (parts of) the variable.
135  DebugLocEntry(const MCSymbol *Begin, const MCSymbol *End,
136                ArrayRef<DbgValueLoc> Vals)
137      : Begin(Begin), End(End) {
138    addValues(Vals);
139  }
140
141  /// Attempt to merge this DebugLocEntry with Next and return
142  /// true if the merge was successful. Entries can be merged if they
143  /// share the same Loc/Constant and if Next immediately follows this
144  /// Entry.
145  bool MergeRanges(const DebugLocEntry &Next) {
146    // If this and Next are describing the same variable, merge them.
147    if ((End == Next.Begin && Values == Next.Values)) {
148      End = Next.End;
149      return true;
150    }
151    return false;
152  }
153
154  const MCSymbol *getBeginSym() const { return Begin; }
155  const MCSymbol *getEndSym() const { return End; }
156  ArrayRef<DbgValueLoc> getValues() const { return Values; }
157  void addValues(ArrayRef<DbgValueLoc> Vals) {
158    Values.append(Vals.begin(), Vals.end());
159    sortUniqueValues();
160    assert((Values.size() == 1 || all_of(Values, [](DbgValueLoc V) {
161              return V.isFragment();
162            })) && "must either have a single value or multiple pieces");
163  }
164
165  // Sort the pieces by offset.
166  // Remove any duplicate entries by dropping all but the first.
167  void sortUniqueValues() {
168    llvm::sort(Values);
169    Values.erase(std::unique(Values.begin(), Values.end(),
170                             [](const DbgValueLoc &A, const DbgValueLoc &B) {
171                               return A.getExpression() == B.getExpression();
172                             }),
173                 Values.end());
174  }
175
176  /// Lower this entry into a DWARF expression.
177  void finalize(const AsmPrinter &AP,
178                DebugLocStream::ListBuilder &List,
179                const DIBasicType *BT,
180                DwarfCompileUnit &TheCU);
181};
182
183/// Compare two DbgValueLocs for equality.
184inline bool operator==(const DbgValueLoc &A,
185                       const DbgValueLoc &B) {
186  if (A.EntryKind != B.EntryKind)
187    return false;
188
189  if (A.Expression != B.Expression)
190    return false;
191
192  switch (A.EntryKind) {
193  case DbgValueLoc::E_Location:
194    return A.Loc == B.Loc;
195  case DbgValueLoc::E_TargetIndexLocation:
196    return A.TIL == B.TIL;
197  case DbgValueLoc::E_Integer:
198    return A.Constant.Int == B.Constant.Int;
199  case DbgValueLoc::E_ConstantFP:
200    return A.Constant.CFP == B.Constant.CFP;
201  case DbgValueLoc::E_ConstantInt:
202    return A.Constant.CIP == B.Constant.CIP;
203  }
204  llvm_unreachable("unhandled EntryKind");
205}
206
207/// Compare two fragments based on their offset.
208inline bool operator<(const DbgValueLoc &A,
209                      const DbgValueLoc &B) {
210  return A.getExpression()->getFragmentInfo()->OffsetInBits <
211         B.getExpression()->getFragmentInfo()->OffsetInBits;
212}
213
214}
215
216#endif
217