llvm/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 /// This struct describes target specific location.
  24 struct 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 within a variable location description, with
  38 /// either a single entry (with an optional DIExpression) used for a DBG_VALUE,
  39 /// or a list of entries used for a DBG_VALUE_LIST.
  40 class DbgValueLocEntry {
  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
  66 public:
  67   DbgValueLocEntry(int64_t i) : EntryKind(E_Integer) { Constant.Int = i; }
  68   DbgValueLocEntry(const ConstantFP *CFP) : EntryKind(E_ConstantFP) {
  69     Constant.CFP = CFP;
  70   }
  71   DbgValueLocEntry(const ConstantInt *CIP) : EntryKind(E_ConstantInt) {
  72     Constant.CIP = CIP;
  73   }
  74   DbgValueLocEntry(MachineLocation Loc) : EntryKind(E_Location), Loc(Loc) {}
  75   DbgValueLocEntry(TargetIndexLocation Loc)
  76       : EntryKind(E_TargetIndexLocation), TIL(Loc) {}
  77
  78   bool isLocation() const { return EntryKind == E_Location; }
  79   bool isTargetIndexLocation() const {
  80     return EntryKind == E_TargetIndexLocation;
  81   }
  82   bool isInt() const { return EntryKind == E_Integer; }
  83   bool isConstantFP() const { return EntryKind == E_ConstantFP; }
  84   bool isConstantInt() const { return EntryKind == E_ConstantInt; }
  85   int64_t getInt() const { return Constant.Int; }
  86   const ConstantFP *getConstantFP() const { return Constant.CFP; }
  87   const ConstantInt *getConstantInt() const { return Constant.CIP; }
  88   MachineLocation getLoc() const { return Loc; }
  89   TargetIndexLocation getTargetIndexLocation() const { return TIL; }
  90   friend bool operator==(const DbgValueLocEntry &, const DbgValueLocEntry &);
  91 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
  92   LLVM_DUMP_METHOD void dump() const {
  93     if (isLocation()) {
  94       llvm::dbgs() << "Loc = { reg=" << Loc.getReg() << " ";
  95       if (Loc.isIndirect())
  96         llvm::dbgs() << "+0";
  97       llvm::dbgs() << "} ";
  98     } else if (isConstantInt())
  99       Constant.CIP->dump();
 100     else if (isConstantFP())
 101       Constant.CFP->dump();
 102   }
 103 #endif
 104 };
 105
 106 /// The location of a single variable, composed of an expression and 0 or more
 107 /// DbgValueLocEntries.
 108 class DbgValueLoc {
 109   /// Any complex address location expression for this DbgValueLoc.
 110   const DIExpression *Expression;
 111
 112   SmallVector<DbgValueLocEntry, 2> ValueLocEntries;
 113
 114   bool IsVariadic;
 115
 116 public:
 117   DbgValueLoc(const DIExpression *Expr, ArrayRef<DbgValueLocEntry> Locs)
 118       : Expression(Expr), ValueLocEntries(Locs.begin(), Locs.end()),
 119         IsVariadic(true) {
 120 #ifndef NDEBUG
 121     // Currently, DBG_VALUE_VAR expressions must use stack_value.
 122     assert(Expr && Expr->isValid() &&
 123            is_contained(Locs, dwarf::DW_OP_stack_value));
 124 #endif
 125   }
 126
 127   DbgValueLoc(const DIExpression *Expr, ArrayRef<DbgValueLocEntry> Locs,
 128               bool IsVariadic)
 129       : Expression(Expr), ValueLocEntries(Locs.begin(), Locs.end()),
 130         IsVariadic(IsVariadic) {
 131 #ifndef NDEBUG
 132     assert(cast<DIExpression>(Expr)->isValid() ||
 133            !any_of(Locs, [](auto LE) { return LE.isLocation(); }));
 134     if (!IsVariadic) {
 135       assert(ValueLocEntries.size() == 1);
 136     } else {
 137       // Currently, DBG_VALUE_VAR expressions must use stack_value.
 138       assert(Expr && Expr->isValid() &&
 139              is_contained(Expr->getElements(), dwarf::DW_OP_stack_value));
 140     }
 141 #endif
 142   }
 143
 144   DbgValueLoc(const DIExpression *Expr, DbgValueLocEntry Loc)
 145       : Expression(Expr), ValueLocEntries(1, Loc), IsVariadic(false) {
 146     assert(((Expr && Expr->isValid()) || !Loc.isLocation()) &&
 147            "DBG_VALUE with a machine location must have a valid expression.");
 148   }
 149
 150   bool isFragment() const { return getExpression()->isFragment(); }
 151   bool isEntryVal() const { return getExpression()->isEntryValue(); }
 152   bool isVariadic() const { return IsVariadic; }
 153   const DIExpression *getExpression() const { return Expression; }
 154   const ArrayRef<DbgValueLocEntry> getLocEntries() const {
 155     return ValueLocEntries;
 156   }
 157   friend bool operator==(const DbgValueLoc &, const DbgValueLoc &);
 158   friend bool operator<(const DbgValueLoc &, const DbgValueLoc &);
 159 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 160   LLVM_DUMP_METHOD void dump() const {
 161     for (const DbgValueLocEntry &DV : ValueLocEntries)
 162       DV.dump();
 163     if (Expression)
 164       Expression->dump();
 165   }
 166 #endif
 167 };
 168
 169 /// This struct describes location entries emitted in the .debug_loc
 170 /// section.
 171 class DebugLocEntry {
 172   /// Begin and end symbols for the address range that this location is valid.
 173   const MCSymbol *Begin;
 174   const MCSymbol *End;
 175
 176   /// A nonempty list of locations/constants belonging to this entry,
 177   /// sorted by offset.
 178   SmallVector<DbgValueLoc, 1> Values;
 179
 180 public:
 181   /// Create a location list entry for the range [\p Begin, \p End).
 182   ///
 183   /// \param Vals One or more values describing (parts of) the variable.
 184   DebugLocEntry(const MCSymbol *Begin, const MCSymbol *End,
 185                 ArrayRef<DbgValueLoc> Vals)
 186       : Begin(Begin), End(End) {
 187     addValues(Vals);
 188   }
 189
 190   /// Attempt to merge this DebugLocEntry with Next and return
 191   /// true if the merge was successful. Entries can be merged if they
 192   /// share the same Loc/Constant and if Next immediately follows this
 193   /// Entry.
 194   bool MergeRanges(const DebugLocEntry &Next) {
 195     // If this and Next are describing the same variable, merge them.
 196     if ((End == Next.Begin && Values == Next.Values)) {
 197       End = Next.End;
 198       return true;
 199     }
 200     return false;
 201   }
 202
 203   const MCSymbol *getBeginSym() const { return Begin; }
 204   const MCSymbol *getEndSym() const { return End; }
 205   ArrayRef<DbgValueLoc> getValues() const { return Values; }
 206   void addValues(ArrayRef<DbgValueLoc> Vals) {
 207     Values.append(Vals.begin(), Vals.end());
 208     sortUniqueValues();
 209     assert((Values.size() == 1 || all_of(Values, [](DbgValueLoc V) {
 210               return V.isFragment();
 211             })) && "must either have a single value or multiple pieces");
 212   }
 213
 214   // Sort the pieces by offset.
 215   // Remove any duplicate entries by dropping all but the first.
 216   void sortUniqueValues() {
 217     llvm::sort(Values);
 218     Values.erase(std::unique(Values.begin(), Values.end(),
 219                              [](const DbgValueLoc &A, const DbgValueLoc &B) {
 220                                return A.getExpression() == B.getExpression();
 221                              }),
 222                  Values.end());
 223   }
 224
 225   /// Lower this entry into a DWARF expression.
 226   void finalize(const AsmPrinter &AP,
 227                 DebugLocStream::ListBuilder &List,
 228                 const DIBasicType *BT,
 229                 DwarfCompileUnit &TheCU);
 230 };
 231
 232 /// Compare two DbgValueLocEntries for equality.
 233 inline bool operator==(const DbgValueLocEntry &A, const DbgValueLocEntry &B) {
 234   if (A.EntryKind != B.EntryKind)
 235     return false;
 236
 237   switch (A.EntryKind) {
 238   case DbgValueLocEntry::E_Location:
 239     return A.Loc == B.Loc;
 240   case DbgValueLocEntry::E_TargetIndexLocation:
 241     return A.TIL == B.TIL;
 242   case DbgValueLocEntry::E_Integer:
 243     return A.Constant.Int == B.Constant.Int;
 244   case DbgValueLocEntry::E_ConstantFP:
 245     return A.Constant.CFP == B.Constant.CFP;
 246   case DbgValueLocEntry::E_ConstantInt:
 247     return A.Constant.CIP == B.Constant.CIP;
 248   }
 249   llvm_unreachable("unhandled EntryKind");
 250 }
 251
 252 /// Compare two DbgValueLocs for equality.
 253 inline bool operator==(const DbgValueLoc &A, const DbgValueLoc &B) {
 254   return A.ValueLocEntries == B.ValueLocEntries &&
 255          A.Expression == B.Expression && A.IsVariadic == B.IsVariadic;
 256 }
 257
 258 /// Compare two fragments based on their offset.
 259 inline bool operator<(const DbgValueLoc &A,
 260                       const DbgValueLoc &B) {
 261   return A.getExpression()->getFragmentInfo()->OffsetInBits <
 262          B.getExpression()->getFragmentInfo()->OffsetInBits;
 263 }
 264
 265 }
 266
 267 #endif