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      1 //===-- llvm/CodeGen/DwarfDebug.h - Dwarf Debug Framework ------*- 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 // This file contains support for writing dwarf debug info into asm files.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef CODEGEN_ASMPRINTER_DWARFDEBUG_H__
     15 #define CODEGEN_ASMPRINTER_DWARFDEBUG_H__
     16 
     17 #include "llvm/CodeGen/AsmPrinter.h"
     18 #include "llvm/CodeGen/LexicalScopes.h"
     19 #include "llvm/MC/MachineLocation.h"
     20 #include "llvm/Analysis/DebugInfo.h"
     21 #include "DIE.h"
     22 #include "llvm/ADT/DenseMap.h"
     23 #include "llvm/ADT/FoldingSet.h"
     24 #include "llvm/ADT/SmallPtrSet.h"
     25 #include "llvm/ADT/StringMap.h"
     26 #include "llvm/ADT/UniqueVector.h"
     27 #include "llvm/Support/Allocator.h"
     28 #include "llvm/Support/DebugLoc.h"
     29 #include <map>
     30 
     31 namespace llvm {
     32 
     33 class CompileUnit;
     34 class DbgConcreteScope;
     35 class DbgVariable;
     36 class MachineFrameInfo;
     37 class MachineModuleInfo;
     38 class MachineOperand;
     39 class MCAsmInfo;
     40 class DIEAbbrev;
     41 class DIE;
     42 class DIEBlock;
     43 class DIEEntry;
     44 
     45 //===----------------------------------------------------------------------===//
     46 /// SrcLineInfo - This class is used to record source line correspondence.
     47 ///
     48 class SrcLineInfo {
     49   unsigned Line;                     // Source line number.
     50   unsigned Column;                   // Source column.
     51   unsigned SourceID;                 // Source ID number.
     52   MCSymbol *Label;                   // Label in code ID number.
     53 public:
     54   SrcLineInfo(unsigned L, unsigned C, unsigned S, MCSymbol *label)
     55     : Line(L), Column(C), SourceID(S), Label(label) {}
     56 
     57   // Accessors
     58   unsigned getLine() const { return Line; }
     59   unsigned getColumn() const { return Column; }
     60   unsigned getSourceID() const { return SourceID; }
     61   MCSymbol *getLabel() const { return Label; }
     62 };
     63 
     64 /// DotDebugLocEntry - This struct describes location entries emitted in
     65 /// .debug_loc section.
     66 typedef struct DotDebugLocEntry {
     67   const MCSymbol *Begin;
     68   const MCSymbol *End;
     69   MachineLocation Loc;
     70   const MDNode *Variable;
     71   bool Merged;
     72   bool Constant;
     73   enum EntryType {
     74     E_Location,
     75     E_Integer,
     76     E_ConstantFP,
     77     E_ConstantInt
     78   };
     79   enum EntryType EntryKind;
     80 
     81   union {
     82     int64_t Int;
     83     const ConstantFP *CFP;
     84     const ConstantInt *CIP;
     85   } Constants;
     86   DotDebugLocEntry()
     87     : Begin(0), End(0), Variable(0), Merged(false),
     88       Constant(false) { Constants.Int = 0;}
     89   DotDebugLocEntry(const MCSymbol *B, const MCSymbol *E, MachineLocation &L,
     90                    const MDNode *V)
     91     : Begin(B), End(E), Loc(L), Variable(V), Merged(false),
     92       Constant(false) { Constants.Int = 0; EntryKind = E_Location; }
     93   DotDebugLocEntry(const MCSymbol *B, const MCSymbol *E, int64_t i)
     94     : Begin(B), End(E), Variable(0), Merged(false),
     95       Constant(true) { Constants.Int = i; EntryKind = E_Integer; }
     96   DotDebugLocEntry(const MCSymbol *B, const MCSymbol *E, const ConstantFP *FPtr)
     97     : Begin(B), End(E), Variable(0), Merged(false),
     98       Constant(true) { Constants.CFP = FPtr; EntryKind = E_ConstantFP; }
     99   DotDebugLocEntry(const MCSymbol *B, const MCSymbol *E, const ConstantInt *IPtr)
    100     : Begin(B), End(E), Variable(0), Merged(false),
    101       Constant(true) { Constants.CIP = IPtr; EntryKind = E_ConstantInt; }
    102 
    103   /// Empty entries are also used as a trigger to emit temp label. Such
    104   /// labels are referenced is used to find debug_loc offset for a given DIE.
    105   bool isEmpty() { return Begin == 0 && End == 0; }
    106   bool isMerged() { return Merged; }
    107   void Merge(DotDebugLocEntry *Next) {
    108     if (!(Begin && Loc == Next->Loc && End == Next->Begin))
    109       return;
    110     Next->Begin = Begin;
    111     Merged = true;
    112   }
    113   bool isLocation() const    { return EntryKind == E_Location; }
    114   bool isInt() const         { return EntryKind == E_Integer; }
    115   bool isConstantFP() const  { return EntryKind == E_ConstantFP; }
    116   bool isConstantInt() const { return EntryKind == E_ConstantInt; }
    117   int64_t getInt()                    { return Constants.Int; }
    118   const ConstantFP *getConstantFP()   { return Constants.CFP; }
    119   const ConstantInt *getConstantInt() { return Constants.CIP; }
    120 } DotDebugLocEntry;
    121 
    122 //===----------------------------------------------------------------------===//
    123 /// DbgVariable - This class is used to track local variable information.
    124 ///
    125 class DbgVariable {
    126   DIVariable Var;                    // Variable Descriptor.
    127   DIE *TheDIE;                       // Variable DIE.
    128   unsigned DotDebugLocOffset;        // Offset in DotDebugLocEntries.
    129   DbgVariable *AbsVar;               // Corresponding Abstract variable, if any.
    130   const MachineInstr *MInsn;         // DBG_VALUE instruction of the variable.
    131   int FrameIndex;
    132 public:
    133   // AbsVar may be NULL.
    134   DbgVariable(DIVariable V, DbgVariable *AV)
    135     : Var(V), TheDIE(0), DotDebugLocOffset(~0U), AbsVar(AV), MInsn(0),
    136       FrameIndex(~0) {}
    137 
    138   // Accessors.
    139   DIVariable getVariable()           const { return Var; }
    140   void setDIE(DIE *D)                      { TheDIE = D; }
    141   DIE *getDIE()                      const { return TheDIE; }
    142   void setDotDebugLocOffset(unsigned O)    { DotDebugLocOffset = O; }
    143   unsigned getDotDebugLocOffset()    const { return DotDebugLocOffset; }
    144   StringRef getName()                const { return Var.getName(); }
    145   DbgVariable *getAbstractVariable() const { return AbsVar; }
    146   const MachineInstr *getMInsn()     const { return MInsn; }
    147   void setMInsn(const MachineInstr *M)     { MInsn = M; }
    148   int getFrameIndex()                const { return FrameIndex; }
    149   void setFrameIndex(int FI)               { FrameIndex = FI; }
    150   // Translate tag to proper Dwarf tag.
    151   unsigned getTag()                  const {
    152     if (Var.getTag() == dwarf::DW_TAG_arg_variable)
    153       return dwarf::DW_TAG_formal_parameter;
    154 
    155     return dwarf::DW_TAG_variable;
    156   }
    157   /// isArtificial - Return true if DbgVariable is artificial.
    158   bool isArtificial()                const {
    159     if (Var.isArtificial())
    160       return true;
    161     if (Var.getTag() == dwarf::DW_TAG_arg_variable
    162         && getType().isArtificial())
    163       return true;
    164     return false;
    165   }
    166   bool variableHasComplexAddress()   const {
    167     assert(Var.Verify() && "Invalid complex DbgVariable!");
    168     return Var.hasComplexAddress();
    169   }
    170   bool isBlockByrefVariable()        const {
    171     assert(Var.Verify() && "Invalid complex DbgVariable!");
    172     return Var.isBlockByrefVariable();
    173   }
    174   unsigned getNumAddrElements()      const {
    175     assert(Var.Verify() && "Invalid complex DbgVariable!");
    176     return Var.getNumAddrElements();
    177   }
    178   uint64_t getAddrElement(unsigned i) const {
    179     return Var.getAddrElement(i);
    180   }
    181   DIType getType() const;
    182 };
    183 
    184 class DwarfDebug {
    185   /// Asm - Target of Dwarf emission.
    186   AsmPrinter *Asm;
    187 
    188   /// MMI - Collected machine module information.
    189   MachineModuleInfo *MMI;
    190 
    191   //===--------------------------------------------------------------------===//
    192   // Attributes used to construct specific Dwarf sections.
    193   //
    194 
    195   CompileUnit *FirstCU;
    196 
    197   /// Maps MDNode with its corresponding CompileUnit.
    198   DenseMap <const MDNode *, CompileUnit *> CUMap;
    199 
    200   /// Maps subprogram MDNode with its corresponding CompileUnit.
    201   DenseMap <const MDNode *, CompileUnit *> SPMap;
    202 
    203   /// AbbreviationsSet - Used to uniquely define abbreviations.
    204   ///
    205   FoldingSet<DIEAbbrev> AbbreviationsSet;
    206 
    207   /// Abbreviations - A list of all the unique abbreviations in use.
    208   ///
    209   std::vector<DIEAbbrev *> Abbreviations;
    210 
    211   /// SourceIdMap - Source id map, i.e. pair of source filename and directory
    212   /// mapped to a unique id.
    213   std::map<std::pair<std::string, std::string>, unsigned> SourceIdMap;
    214 
    215   /// StringPool - A String->Symbol mapping of strings used by indirect
    216   /// references.
    217   StringMap<std::pair<MCSymbol*, unsigned> > StringPool;
    218   unsigned NextStringPoolNumber;
    219 
    220   MCSymbol *getStringPoolEntry(StringRef Str);
    221 
    222   /// SectionMap - Provides a unique id per text section.
    223   ///
    224   UniqueVector<const MCSection*> SectionMap;
    225 
    226   /// CurrentFnArguments - List of Arguments (DbgValues) for current function.
    227   SmallVector<DbgVariable *, 8> CurrentFnArguments;
    228 
    229   LexicalScopes LScopes;
    230 
    231   /// AbstractSPDies - Collection of abstract subprogram DIEs.
    232   DenseMap<const MDNode *, DIE *> AbstractSPDies;
    233 
    234   /// ScopeVariables - Collection of dbg variables of a scope.
    235   DenseMap<LexicalScope *, SmallVector<DbgVariable *, 8> > ScopeVariables;
    236 
    237   /// AbstractVariables - Collection on abstract variables.
    238   DenseMap<const MDNode *, DbgVariable *> AbstractVariables;
    239 
    240   /// DotDebugLocEntries - Collection of DotDebugLocEntry.
    241   SmallVector<DotDebugLocEntry, 4> DotDebugLocEntries;
    242 
    243   /// InlinedSubprogramDIEs - Collection of subprogram DIEs that are marked
    244   /// (at the end of the module) as DW_AT_inline.
    245   SmallPtrSet<DIE *, 4> InlinedSubprogramDIEs;
    246 
    247   /// InlineInfo - Keep track of inlined functions and their location.  This
    248   /// information is used to populate debug_inlined section.
    249   typedef std::pair<const MCSymbol *, DIE *> InlineInfoLabels;
    250   DenseMap<const MDNode *, SmallVector<InlineInfoLabels, 4> > InlineInfo;
    251   SmallVector<const MDNode *, 4> InlinedSPNodes;
    252 
    253   // ProcessedSPNodes - This is a collection of subprogram MDNodes that
    254   // are processed to create DIEs.
    255   SmallPtrSet<const MDNode *, 16> ProcessedSPNodes;
    256 
    257   /// LabelsBeforeInsn - Maps instruction with label emitted before
    258   /// instruction.
    259   DenseMap<const MachineInstr *, MCSymbol *> LabelsBeforeInsn;
    260 
    261   /// LabelsAfterInsn - Maps instruction with label emitted after
    262   /// instruction.
    263   DenseMap<const MachineInstr *, MCSymbol *> LabelsAfterInsn;
    264 
    265   /// UserVariables - Every user variable mentioned by a DBG_VALUE instruction
    266   /// in order of appearance.
    267   SmallVector<const MDNode*, 8> UserVariables;
    268 
    269   /// DbgValues - For each user variable, keep a list of DBG_VALUE
    270   /// instructions in order. The list can also contain normal instructions that
    271   /// clobber the previous DBG_VALUE.
    272   typedef DenseMap<const MDNode*, SmallVector<const MachineInstr*, 4> >
    273     DbgValueHistoryMap;
    274   DbgValueHistoryMap DbgValues;
    275 
    276   SmallVector<const MCSymbol *, 8> DebugRangeSymbols;
    277 
    278   /// Previous instruction's location information. This is used to determine
    279   /// label location to indicate scope boundries in dwarf debug info.
    280   DebugLoc PrevInstLoc;
    281   MCSymbol *PrevLabel;
    282 
    283   /// PrologEndLoc - This location indicates end of function prologue and
    284   /// beginning of function body.
    285   DebugLoc PrologEndLoc;
    286 
    287   struct FunctionDebugFrameInfo {
    288     unsigned Number;
    289     std::vector<MachineMove> Moves;
    290 
    291     FunctionDebugFrameInfo(unsigned Num, const std::vector<MachineMove> &M)
    292       : Number(Num), Moves(M) {}
    293   };
    294 
    295   std::vector<FunctionDebugFrameInfo> DebugFrames;
    296 
    297   // DIEValueAllocator - All DIEValues are allocated through this allocator.
    298   BumpPtrAllocator DIEValueAllocator;
    299 
    300   // Section Symbols: these are assembler temporary labels that are emitted at
    301   // the beginning of each supported dwarf section.  These are used to form
    302   // section offsets and are created by EmitSectionLabels.
    303   MCSymbol *DwarfInfoSectionSym, *DwarfAbbrevSectionSym;
    304   MCSymbol *DwarfStrSectionSym, *TextSectionSym, *DwarfDebugRangeSectionSym;
    305   MCSymbol *DwarfDebugLocSectionSym;
    306   MCSymbol *FunctionBeginSym, *FunctionEndSym;
    307 
    308 private:
    309 
    310   /// assignAbbrevNumber - Define a unique number for the abbreviation.
    311   ///
    312   void assignAbbrevNumber(DIEAbbrev &Abbrev);
    313 
    314   void addScopeVariable(LexicalScope *LS, DbgVariable *Var);
    315 
    316   /// findAbstractVariable - Find abstract variable associated with Var.
    317   DbgVariable *findAbstractVariable(DIVariable &Var, DebugLoc Loc);
    318 
    319   /// updateSubprogramScopeDIE - Find DIE for the given subprogram and
    320   /// attach appropriate DW_AT_low_pc and DW_AT_high_pc attributes.
    321   /// If there are global variables in this scope then create and insert
    322   /// DIEs for these variables.
    323   DIE *updateSubprogramScopeDIE(CompileUnit *SPCU, const MDNode *SPNode);
    324 
    325   /// constructLexicalScope - Construct new DW_TAG_lexical_block
    326   /// for this scope and attach DW_AT_low_pc/DW_AT_high_pc labels.
    327   DIE *constructLexicalScopeDIE(CompileUnit *TheCU, LexicalScope *Scope);
    328 
    329   /// constructInlinedScopeDIE - This scope represents inlined body of
    330   /// a function. Construct DIE to represent this concrete inlined copy
    331   /// of the function.
    332   DIE *constructInlinedScopeDIE(CompileUnit *TheCU, LexicalScope *Scope);
    333 
    334   /// constructVariableDIE - Construct a DIE for the given DbgVariable.
    335   DIE *constructVariableDIE(DbgVariable *DV, LexicalScope *S);
    336 
    337   /// constructScopeDIE - Construct a DIE for this scope.
    338   DIE *constructScopeDIE(CompileUnit *TheCU, LexicalScope *Scope);
    339 
    340   /// EmitSectionLabels - Emit initial Dwarf sections with a label at
    341   /// the start of each one.
    342   void EmitSectionLabels();
    343 
    344   /// emitDIE - Recursively Emits a debug information entry.
    345   ///
    346   void emitDIE(DIE *Die);
    347 
    348   /// computeSizeAndOffset - Compute the size and offset of a DIE.
    349   ///
    350   unsigned computeSizeAndOffset(DIE *Die, unsigned Offset, bool Last);
    351 
    352   /// computeSizeAndOffsets - Compute the size and offset of all the DIEs.
    353   ///
    354   void computeSizeAndOffsets();
    355 
    356   /// EmitDebugInfo - Emit the debug info section.
    357   ///
    358   void emitDebugInfo();
    359 
    360   /// emitAbbreviations - Emit the abbreviation section.
    361   ///
    362   void emitAbbreviations() const;
    363 
    364   /// emitEndOfLineMatrix - Emit the last address of the section and the end of
    365   /// the line matrix.
    366   ///
    367   void emitEndOfLineMatrix(unsigned SectionEnd);
    368 
    369   /// emitDebugPubNames - Emit visible names into a debug pubnames section.
    370   ///
    371   void emitDebugPubNames();
    372 
    373   /// emitDebugPubTypes - Emit visible types into a debug pubtypes section.
    374   ///
    375   void emitDebugPubTypes();
    376 
    377   /// emitDebugStr - Emit visible names into a debug str section.
    378   ///
    379   void emitDebugStr();
    380 
    381   /// emitDebugLoc - Emit visible names into a debug loc section.
    382   ///
    383   void emitDebugLoc();
    384 
    385   /// EmitDebugARanges - Emit visible names into a debug aranges section.
    386   ///
    387   void EmitDebugARanges();
    388 
    389   /// emitDebugRanges - Emit visible names into a debug ranges section.
    390   ///
    391   void emitDebugRanges();
    392 
    393   /// emitDebugMacInfo - Emit visible names into a debug macinfo section.
    394   ///
    395   void emitDebugMacInfo();
    396 
    397   /// emitDebugInlineInfo - Emit inline info using following format.
    398   /// Section Header:
    399   /// 1. length of section
    400   /// 2. Dwarf version number
    401   /// 3. address size.
    402   ///
    403   /// Entries (one "entry" for each function that was inlined):
    404   ///
    405   /// 1. offset into __debug_str section for MIPS linkage name, if exists;
    406   ///   otherwise offset into __debug_str for regular function name.
    407   /// 2. offset into __debug_str section for regular function name.
    408   /// 3. an unsigned LEB128 number indicating the number of distinct inlining
    409   /// instances for the function.
    410   ///
    411   /// The rest of the entry consists of a {die_offset, low_pc} pair for each
    412   /// inlined instance; the die_offset points to the inlined_subroutine die in
    413   /// the __debug_info section, and the low_pc is the starting address for the
    414   /// inlining instance.
    415   void emitDebugInlineInfo();
    416 
    417   /// constructCompileUnit - Create new CompileUnit for the given
    418   /// metadata node with tag DW_TAG_compile_unit.
    419   CompileUnit *constructCompileUnit(const MDNode *N);
    420 
    421   /// construct SubprogramDIE - Construct subprogram DIE.
    422   void constructSubprogramDIE(CompileUnit *TheCU, const MDNode *N);
    423 
    424   /// recordSourceLine - Register a source line with debug info. Returns the
    425   /// unique label that was emitted and which provides correspondence to
    426   /// the source line list.
    427   void recordSourceLine(unsigned Line, unsigned Col, const MDNode *Scope,
    428                         unsigned Flags);
    429 
    430   /// identifyScopeMarkers() - Indentify instructions that are marking the
    431   /// beginning of or ending of a scope.
    432   void identifyScopeMarkers();
    433 
    434   /// addCurrentFnArgument - If Var is an current function argument that add
    435   /// it in CurrentFnArguments list.
    436   bool addCurrentFnArgument(const MachineFunction *MF,
    437                             DbgVariable *Var, LexicalScope *Scope);
    438 
    439   /// collectVariableInfo - Populate LexicalScope entries with variables' info.
    440   void collectVariableInfo(const MachineFunction *,
    441                            SmallPtrSet<const MDNode *, 16> &ProcessedVars);
    442 
    443   /// collectVariableInfoFromMMITable - Collect variable information from
    444   /// side table maintained by MMI.
    445   void collectVariableInfoFromMMITable(const MachineFunction * MF,
    446                                        SmallPtrSet<const MDNode *, 16> &P);
    447 
    448   /// requestLabelBeforeInsn - Ensure that a label will be emitted before MI.
    449   void requestLabelBeforeInsn(const MachineInstr *MI) {
    450     LabelsBeforeInsn.insert(std::make_pair(MI, (MCSymbol*)0));
    451   }
    452 
    453   /// getLabelBeforeInsn - Return Label preceding the instruction.
    454   const MCSymbol *getLabelBeforeInsn(const MachineInstr *MI);
    455 
    456   /// requestLabelAfterInsn - Ensure that a label will be emitted after MI.
    457   void requestLabelAfterInsn(const MachineInstr *MI) {
    458     LabelsAfterInsn.insert(std::make_pair(MI, (MCSymbol*)0));
    459   }
    460 
    461   /// getLabelAfterInsn - Return Label immediately following the instruction.
    462   const MCSymbol *getLabelAfterInsn(const MachineInstr *MI);
    463 
    464 public:
    465   //===--------------------------------------------------------------------===//
    466   // Main entry points.
    467   //
    468   DwarfDebug(AsmPrinter *A, Module *M);
    469   ~DwarfDebug();
    470 
    471   /// collectInfoFromNamedMDNodes - Collect debug info from named mdnodes such
    472   /// as llvm.dbg.enum and llvm.dbg.ty
    473   void collectInfoFromNamedMDNodes(Module *M);
    474 
    475   /// collectLegacyDebugInfo - Collect debug info using DebugInfoFinder.
    476   /// FIXME - Remove this when DragonEgg switches to DIBuilder.
    477   bool collectLegacyDebugInfo(Module *M);
    478 
    479   /// beginModule - Emit all Dwarf sections that should come prior to the
    480   /// content.
    481   void beginModule(Module *M);
    482 
    483   /// endModule - Emit all Dwarf sections that should come after the content.
    484   ///
    485   void endModule();
    486 
    487   /// beginFunction - Gather pre-function debug information.  Assumes being
    488   /// emitted immediately after the function entry point.
    489   void beginFunction(const MachineFunction *MF);
    490 
    491   /// endFunction - Gather and emit post-function debug information.
    492   ///
    493   void endFunction(const MachineFunction *MF);
    494 
    495   /// beginInstruction - Process beginning of an instruction.
    496   void beginInstruction(const MachineInstr *MI);
    497 
    498   /// endInstruction - Prcess end of an instruction.
    499   void endInstruction(const MachineInstr *MI);
    500 
    501   /// GetOrCreateSourceID - Look up the source id with the given directory and
    502   /// source file names. If none currently exists, create a new id and insert it
    503   /// in the SourceIds map.
    504   unsigned GetOrCreateSourceID(StringRef DirName, StringRef FullName);
    505 
    506   /// createSubprogramDIE - Create new DIE using SP.
    507   DIE *createSubprogramDIE(DISubprogram SP);
    508 };
    509 } // End of namespace llvm
    510 
    511 #endif
    512