DebugLocEntry.h revision dce4a407a24b04eebc6a376f8e62b41aaa7b071f 
1//===-- llvm/CodeGen/DebugLocEntry.h - Entry in debug_loc list -*- 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#ifndef CODEGEN_ASMPRINTER_DEBUGLOCENTRY_H__
11#define CODEGEN_ASMPRINTER_DEBUGLOCENTRY_H__
12#include "llvm/IR/Constants.h"
13#include "llvm/MC/MachineLocation.h"
14#include "llvm/MC/MCSymbol.h"
15
16namespace llvm {
17class DwarfCompileUnit;
18class MDNode;
19/// \brief This struct describes location entries emitted in the .debug_loc
20/// section.
21class DebugLocEntry {
22  // Begin and end symbols for the address range that this location is valid.
23  const MCSymbol *Begin;
24  const MCSymbol *End;
25
26public:
27  /// A single location or constant.
28  struct Value {
29    Value(const MDNode *Var, int64_t i)
30      : Variable(Var), EntryKind(E_Integer) {
31      Constant.Int = i;
32    }
33    Value(const MDNode *Var, const ConstantFP *CFP)
34      : Variable(Var), EntryKind(E_ConstantFP) {
35      Constant.CFP = CFP;
36    }
37    Value(const MDNode *Var, const ConstantInt *CIP)
38      : Variable(Var), EntryKind(E_ConstantInt) {
39      Constant.CIP = CIP;
40    }
41    Value(const MDNode *Var, MachineLocation Loc)
42      : Variable(Var), EntryKind(E_Location), Loc(Loc) {
43    }
44
45    // The variable to which this location entry corresponds.
46    const MDNode *Variable;
47
48    // Type of entry that this represents.
49    enum EntryType { E_Location, E_Integer, E_ConstantFP, E_ConstantInt };
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    // Or a location in the machine frame.
60    MachineLocation Loc;
61
62    bool operator==(const Value &other) const {
63      if (EntryKind != other.EntryKind)
64        return false;
65
66      switch (EntryKind) {
67      case E_Location:
68        return Loc == other.Loc;
69      case E_Integer:
70        return Constant.Int == other.Constant.Int;
71      case E_ConstantFP:
72        return Constant.CFP == other.Constant.CFP;
73      case E_ConstantInt:
74        return Constant.CIP == other.Constant.CIP;
75      }
76      llvm_unreachable("unhandled EntryKind");
77    }
78
79    bool isLocation() const { return EntryKind == E_Location; }
80    bool isInt() const { return EntryKind == E_Integer; }
81    bool isConstantFP() const { return EntryKind == E_ConstantFP; }
82    bool isConstantInt() const { return EntryKind == E_ConstantInt; }
83    int64_t getInt() const { return Constant.Int; }
84    const ConstantFP *getConstantFP() const { return Constant.CFP; }
85    const ConstantInt *getConstantInt() const { return Constant.CIP; }
86    MachineLocation getLoc() const { return Loc; }
87    const MDNode *getVariable() const { return Variable; }
88  };
89private:
90  /// A list of locations/constants belonging to this entry.
91  SmallVector<Value, 1> Values;
92
93  /// The compile unit that this location entry is referenced by.
94  const DwarfCompileUnit *Unit;
95
96public:
97  DebugLocEntry() : Begin(nullptr), End(nullptr), Unit(nullptr) {}
98  DebugLocEntry(const MCSymbol *B, const MCSymbol *E,
99                Value Val, const DwarfCompileUnit *U)
100      : Begin(B), End(E), Unit(U) {
101    Values.push_back(std::move(Val));
102  }
103
104  /// \brief Attempt to merge this DebugLocEntry with Next and return
105  /// true if the merge was successful. Entries can be merged if they
106  /// share the same Loc/Constant and if Next immediately follows this
107  /// Entry.
108  bool Merge(const DebugLocEntry &Next) {
109    if ((End == Next.Begin && Values == Next.Values)) {
110      End = Next.End;
111      return true;
112    }
113    return false;
114  }
115  const MCSymbol *getBeginSym() const { return Begin; }
116  const MCSymbol *getEndSym() const { return End; }
117  const DwarfCompileUnit *getCU() const { return Unit; }
118  const ArrayRef<Value> getValues() const { return Values; }
119  void addValue(Value Val) { Values.push_back(Val); }
120};
121
122}
123#endif
124