lib/CodeGen/AsmPrinter/DebugLocEntry.h

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