include/llvm/MC/MCCodeView.h

   1 //===- MCCodeView.h - Machine Code CodeView support -------------*- 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 // Holds state from .cv_file and .cv_loc directives for later emission.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #ifndef LLVM_MC_MCCODEVIEW_H
  14 #define LLVM_MC_MCCODEVIEW_H
  15
  16 #include "llvm/ADT/StringMap.h"
  17 #include "llvm/ADT/StringRef.h"
  18 #include "llvm/MC/MCFragment.h"
  19 #include "llvm/MC/MCObjectStreamer.h"
  20 #include <map>
  21 #include <vector>
  22
  23 namespace llvm {
  24 class MCContext;
  25 class MCObjectStreamer;
  26 class MCStreamer;
  27 class CodeViewContext;
  28
  29 /// Instances of this class represent the information from a
  30 /// .cv_loc directive.
  31 class MCCVLoc {
  32   const MCSymbol *Label = nullptr;
  33   uint32_t FunctionId;
  34   uint32_t FileNum;
  35   uint32_t Line;
  36   uint16_t Column;
  37   uint16_t PrologueEnd : 1;
  38   uint16_t IsStmt : 1;
  39
  40 private: // CodeViewContext manages these
  41   friend class CodeViewContext;
  42   MCCVLoc(const MCSymbol *Label, unsigned functionid, unsigned fileNum,
  43           unsigned line, unsigned column, bool prologueend, bool isstmt)
  44       : Label(Label), FunctionId(functionid), FileNum(fileNum), Line(line),
  45         Column(column), PrologueEnd(prologueend), IsStmt(isstmt) {}
  46
  47   // Allow the default copy constructor and assignment operator to be used
  48   // for an MCCVLoc object.
  49
  50 public:
  51   const MCSymbol *getLabel() const { return Label; }
  52
  53   unsigned getFunctionId() const { return FunctionId; }
  54
  55   /// Get the FileNum of this MCCVLoc.
  56   unsigned getFileNum() const { return FileNum; }
  57
  58   /// Get the Line of this MCCVLoc.
  59   unsigned getLine() const { return Line; }
  60
  61   /// Get the Column of this MCCVLoc.
  62   unsigned getColumn() const { return Column; }
  63
  64   bool isPrologueEnd() const { return PrologueEnd; }
  65   bool isStmt() const { return IsStmt; }
  66
  67   void setLabel(const MCSymbol *L) { Label = L; }
  68
  69   void setFunctionId(unsigned FID) { FunctionId = FID; }
  70
  71   /// Set the FileNum of this MCCVLoc.
  72   void setFileNum(unsigned fileNum) { FileNum = fileNum; }
  73
  74   /// Set the Line of this MCCVLoc.
  75   void setLine(unsigned line) { Line = line; }
  76
  77   /// Set the Column of this MCCVLoc.
  78   void setColumn(unsigned column) {
  79     assert(column <= UINT16_MAX);
  80     Column = column;
  81   }
  82
  83   void setPrologueEnd(bool PE) { PrologueEnd = PE; }
  84   void setIsStmt(bool IS) { IsStmt = IS; }
  85 };
  86
  87 /// Information describing a function or inlined call site introduced by
  88 /// .cv_func_id or .cv_inline_site_id. Accumulates information from .cv_loc
  89 /// directives used with this function's id or the id of an inlined call site
  90 /// within this function or inlined call site.
  91 struct MCCVFunctionInfo {
  92   /// If this represents an inlined call site, then ParentFuncIdPlusOne will be
  93   /// the parent function id plus one. If this represents a normal function,
  94   /// then there is no parent, and ParentFuncIdPlusOne will be FunctionSentinel.
  95   /// If this struct is an unallocated slot in the function info vector, then
  96   /// ParentFuncIdPlusOne will be zero.
  97   unsigned ParentFuncIdPlusOne = 0;
  98
  99   enum : unsigned { FunctionSentinel = ~0U };
 100
 101   struct LineInfo {
 102     unsigned File;
 103     unsigned Line;
 104     unsigned Col;
 105   };
 106
 107   LineInfo InlinedAt;
 108
 109   /// The section of the first .cv_loc directive used for this function, or null
 110   /// if none has been seen yet.
 111   MCSection *Section = nullptr;
 112
 113   /// Map from inlined call site id to the inlined at location to use for that
 114   /// call site. Call chains are collapsed, so for the call chain 'f -> g -> h',
 115   /// the InlinedAtMap of 'f' will contain entries for 'g' and 'h' that both
 116   /// list the line info for the 'g' call site.
 117   DenseMap<unsigned, LineInfo> InlinedAtMap;
 118
 119   /// Returns true if this is function info has not yet been used in a
 120   /// .cv_func_id or .cv_inline_site_id directive.
 121   bool isUnallocatedFunctionInfo() const { return ParentFuncIdPlusOne == 0; }
 122
 123   /// Returns true if this represents an inlined call site, meaning
 124   /// ParentFuncIdPlusOne is neither zero nor ~0U.
 125   bool isInlinedCallSite() const {
 126     return !isUnallocatedFunctionInfo() &&
 127            ParentFuncIdPlusOne != FunctionSentinel;
 128   }
 129
 130   unsigned getParentFuncId() const {
 131     assert(isInlinedCallSite());
 132     return ParentFuncIdPlusOne - 1;
 133   }
 134 };
 135
 136 /// Holds state from .cv_file and .cv_loc directives for later emission.
 137 class CodeViewContext {
 138 public:
 139   CodeViewContext();
 140   ~CodeViewContext();
 141
 142   bool isValidFileNumber(unsigned FileNumber) const;
 143   bool addFile(MCStreamer &OS, unsigned FileNumber, StringRef Filename,
 144                ArrayRef<uint8_t> ChecksumBytes, uint8_t ChecksumKind);
 145
 146   /// Records the function id of a normal function. Returns false if the
 147   /// function id has already been used, and true otherwise.
 148   bool recordFunctionId(unsigned FuncId);
 149
 150   /// Records the function id of an inlined call site. Records the "inlined at"
 151   /// location info of the call site, including what function or inlined call
 152   /// site it was inlined into. Returns false if the function id has already
 153   /// been used, and true otherwise.
 154   bool recordInlinedCallSiteId(unsigned FuncId, unsigned IAFunc,
 155                                unsigned IAFile, unsigned IALine,
 156                                unsigned IACol);
 157
 158   /// Retreive the function info if this is a valid function id, or nullptr.
 159   MCCVFunctionInfo *getCVFunctionInfo(unsigned FuncId);
 160
 161   /// Saves the information from the currently parsed .cv_loc directive
 162   /// and sets CVLocSeen.  When the next instruction is assembled an entry
 163   /// in the line number table with this information and the address of the
 164   /// instruction will be created.
 165   void recordCVLoc(MCContext &Ctx, const MCSymbol *Label, unsigned FunctionId,
 166                    unsigned FileNo, unsigned Line, unsigned Column,
 167                    bool PrologueEnd, bool IsStmt);
 168
 169   bool isValidCVFileNumber(unsigned FileNumber);
 170
 171   /// Add a line entry.
 172   void addLineEntry(const MCCVLoc &LineEntry);
 173
 174   std::vector<MCCVLoc> getFunctionLineEntries(unsigned FuncId);
 175
 176   std::pair<size_t, size_t> getLineExtent(unsigned FuncId);
 177
 178   ArrayRef<MCCVLoc> getLinesForExtent(size_t L, size_t R);
 179
 180   /// Emits a line table substream.
 181   void emitLineTableForFunction(MCObjectStreamer &OS, unsigned FuncId,
 182                                 const MCSymbol *FuncBegin,
 183                                 const MCSymbol *FuncEnd);
 184
 185   void emitInlineLineTableForFunction(MCObjectStreamer &OS,
 186                                       unsigned PrimaryFunctionId,
 187                                       unsigned SourceFileId,
 188                                       unsigned SourceLineNum,
 189                                       const MCSymbol *FnStartSym,
 190                                       const MCSymbol *FnEndSym);
 191
 192   /// Encodes the binary annotations once we have a layout.
 193   void encodeInlineLineTable(MCAsmLayout &Layout,
 194                              MCCVInlineLineTableFragment &F);
 195
 196   MCFragment *
 197   emitDefRange(MCObjectStreamer &OS,
 198                ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
 199                StringRef FixedSizePortion);
 200
 201   void encodeDefRange(MCAsmLayout &Layout, MCCVDefRangeFragment &F);
 202
 203   /// Emits the string table substream.
 204   void emitStringTable(MCObjectStreamer &OS);
 205
 206   /// Emits the file checksum substream.
 207   void emitFileChecksums(MCObjectStreamer &OS);
 208
 209   /// Emits the offset into the checksum table of the given file number.
 210   void emitFileChecksumOffset(MCObjectStreamer &OS, unsigned FileNo);
 211
 212   /// Add something to the string table.  Returns the final string as well as
 213   /// offset into the string table.
 214   std::pair<StringRef, unsigned> addToStringTable(StringRef S);
 215
 216 private:
 217   /// Map from string to string table offset.
 218   StringMap<unsigned> StringTable;
 219
 220   /// The fragment that ultimately holds our strings.
 221   MCDataFragment *StrTabFragment = nullptr;
 222   bool InsertedStrTabFragment = false;
 223
 224   MCDataFragment *getStringTableFragment();
 225
 226   /// Get a string table offset.
 227   unsigned getStringTableOffset(StringRef S);
 228
 229   struct FileInfo {
 230     unsigned StringTableOffset;
 231
 232     // Indicates if this FileInfo corresponds to an actual file, or hasn't been
 233     // set yet.
 234     bool Assigned = false;
 235
 236     uint8_t ChecksumKind;
 237
 238     ArrayRef<uint8_t> Checksum;
 239
 240     // Checksum offset stored as a symbol because it might be requested
 241     // before it has been calculated, so a fixup may be needed.
 242     MCSymbol *ChecksumTableOffset;
 243   };
 244
 245   /// Array storing added file information.
 246   SmallVector<FileInfo, 4> Files;
 247
 248   /// The offset of the first and last .cv_loc directive for a given function
 249   /// id.
 250   std::map<unsigned, std::pair<size_t, size_t>> MCCVLineStartStop;
 251
 252   /// A collection of MCCVLoc for each section.
 253   std::vector<MCCVLoc> MCCVLines;
 254
 255   /// All known functions and inlined call sites, indexed by function id.
 256   std::vector<MCCVFunctionInfo> Functions;
 257
 258   /// Indicate whether we have already laid out the checksum table addresses or
 259   /// not.
 260   bool ChecksumOffsetsAssigned = false;
 261 };
 262
 263 } // end namespace llvm
 264 #endif