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/ArrayRef.h"
17#include "llvm/ADT/DenseMap.h"
18#include "llvm/ADT/SmallVector.h"
19#include "llvm/ADT/StringMap.h"
20#include "llvm/ADT/StringRef.h"
21#include <map>
22#include <vector>
23
24namespace llvm {
25class MCAsmLayout;
26class MCCVDefRangeFragment;
27class MCCVInlineLineTableFragment;
28class MCDataFragment;
29class MCFragment;
30class MCSection;
31class MCSymbol;
32class MCContext;
33class MCObjectStreamer;
34class MCStreamer;
35
36/// Instances of this class represent the information from a
37/// .cv_loc directive.
38class MCCVLoc {
39  const MCSymbol *Label = nullptr;
40  uint32_t FunctionId;
41  uint32_t FileNum;
42  uint32_t Line;
43  uint16_t Column;
44  uint16_t PrologueEnd : 1;
45  uint16_t IsStmt : 1;
46
47private: // CodeViewContext manages these
48  friend class CodeViewContext;
49  MCCVLoc(const MCSymbol *Label, unsigned functionid, unsigned fileNum,
50          unsigned line, unsigned column, bool prologueend, bool isstmt)
51      : Label(Label), FunctionId(functionid), FileNum(fileNum), Line(line),
52        Column(column), PrologueEnd(prologueend), IsStmt(isstmt) {}
53
54  // Allow the default copy constructor and assignment operator to be used
55  // for an MCCVLoc object.
56
57public:
58  const MCSymbol *getLabel() const { return Label; }
59
60  unsigned getFunctionId() const { return FunctionId; }
61
62  /// Get the FileNum of this MCCVLoc.
63  unsigned getFileNum() const { return FileNum; }
64
65  /// Get the Line of this MCCVLoc.
66  unsigned getLine() const { return Line; }
67
68  /// Get the Column of this MCCVLoc.
69  unsigned getColumn() const { return Column; }
70
71  bool isPrologueEnd() const { return PrologueEnd; }
72  bool isStmt() const { return IsStmt; }
73
74  void setLabel(const MCSymbol *L) { Label = L; }
75
76  void setFunctionId(unsigned FID) { FunctionId = FID; }
77
78  /// Set the FileNum of this MCCVLoc.
79  void setFileNum(unsigned fileNum) { FileNum = fileNum; }
80
81  /// Set the Line of this MCCVLoc.
82  void setLine(unsigned line) { Line = line; }
83
84  /// Set the Column of this MCCVLoc.
85  void setColumn(unsigned column) {
86    assert(column <= UINT16_MAX);
87    Column = column;
88  }
89
90  void setPrologueEnd(bool PE) { PrologueEnd = PE; }
91  void setIsStmt(bool IS) { IsStmt = IS; }
92};
93
94/// Information describing a function or inlined call site introduced by
95/// .cv_func_id or .cv_inline_site_id. Accumulates information from .cv_loc
96/// directives used with this function's id or the id of an inlined call site
97/// within this function or inlined call site.
98struct MCCVFunctionInfo {
99  /// If this represents an inlined call site, then ParentFuncIdPlusOne will be
100  /// the parent function id plus one. If this represents a normal function,
101  /// then there is no parent, and ParentFuncIdPlusOne will be FunctionSentinel.
102  /// If this struct is an unallocated slot in the function info vector, then
103  /// ParentFuncIdPlusOne will be zero.
104  unsigned ParentFuncIdPlusOne = 0;
105
106  enum : unsigned { FunctionSentinel = ~0U };
107
108  struct LineInfo {
109    unsigned File;
110    unsigned Line;
111    unsigned Col;
112  };
113
114  LineInfo InlinedAt;
115
116  /// The section of the first .cv_loc directive used for this function, or null
117  /// if none has been seen yet.
118  MCSection *Section = nullptr;
119
120  /// Map from inlined call site id to the inlined at location to use for that
121  /// call site. Call chains are collapsed, so for the call chain 'f -> g -> h',
122  /// the InlinedAtMap of 'f' will contain entries for 'g' and 'h' that both
123  /// list the line info for the 'g' call site.
124  DenseMap<unsigned, LineInfo> InlinedAtMap;
125
126  /// Returns true if this is function info has not yet been used in a
127  /// .cv_func_id or .cv_inline_site_id directive.
128  bool isUnallocatedFunctionInfo() const { return ParentFuncIdPlusOne == 0; }
129
130  /// Returns true if this represents an inlined call site, meaning
131  /// ParentFuncIdPlusOne is neither zero nor ~0U.
132  bool isInlinedCallSite() const {
133    return !isUnallocatedFunctionInfo() &&
134           ParentFuncIdPlusOne != FunctionSentinel;
135  }
136
137  unsigned getParentFuncId() const {
138    assert(isInlinedCallSite());
139    return ParentFuncIdPlusOne - 1;
140  }
141};
142
143/// Holds state from .cv_file and .cv_loc directives for later emission.
144class CodeViewContext {
145public:
146  CodeViewContext();
147  ~CodeViewContext();
148
149  bool isValidFileNumber(unsigned FileNumber) const;
150  bool addFile(MCStreamer &OS, unsigned FileNumber, StringRef Filename,
151               ArrayRef<uint8_t> ChecksumBytes, uint8_t ChecksumKind);
152
153  /// Records the function id of a normal function. Returns false if the
154  /// function id has already been used, and true otherwise.
155  bool recordFunctionId(unsigned FuncId);
156
157  /// Records the function id of an inlined call site. Records the "inlined at"
158  /// location info of the call site, including what function or inlined call
159  /// site it was inlined into. Returns false if the function id has already
160  /// been used, and true otherwise.
161  bool recordInlinedCallSiteId(unsigned FuncId, unsigned IAFunc,
162                               unsigned IAFile, unsigned IALine,
163                               unsigned IACol);
164
165  /// Retreive the function info if this is a valid function id, or nullptr.
166  MCCVFunctionInfo *getCVFunctionInfo(unsigned FuncId);
167
168  /// Saves the information from the currently parsed .cv_loc directive
169  /// and sets CVLocSeen.  When the next instruction is assembled an entry
170  /// in the line number table with this information and the address of the
171  /// instruction will be created.
172  void recordCVLoc(MCContext &Ctx, const MCSymbol *Label, unsigned FunctionId,
173                   unsigned FileNo, unsigned Line, unsigned Column,
174                   bool PrologueEnd, bool IsStmt);
175
176  /// Add a line entry.
177  void addLineEntry(const MCCVLoc &LineEntry);
178
179  std::vector<MCCVLoc> getFunctionLineEntries(unsigned FuncId);
180
181  std::pair<size_t, size_t> getLineExtent(unsigned FuncId);
182
183  ArrayRef<MCCVLoc> getLinesForExtent(size_t L, size_t R);
184
185  /// Emits a line table substream.
186  void emitLineTableForFunction(MCObjectStreamer &OS, unsigned FuncId,
187                                const MCSymbol *FuncBegin,
188                                const MCSymbol *FuncEnd);
189
190  void emitInlineLineTableForFunction(MCObjectStreamer &OS,
191                                      unsigned PrimaryFunctionId,
192                                      unsigned SourceFileId,
193                                      unsigned SourceLineNum,
194                                      const MCSymbol *FnStartSym,
195                                      const MCSymbol *FnEndSym);
196
197  /// Encodes the binary annotations once we have a layout.
198  void encodeInlineLineTable(MCAsmLayout &Layout,
199                             MCCVInlineLineTableFragment &F);
200
201  MCFragment *
202  emitDefRange(MCObjectStreamer &OS,
203               ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
204               StringRef FixedSizePortion);
205
206  void encodeDefRange(MCAsmLayout &Layout, MCCVDefRangeFragment &F);
207
208  /// Emits the string table substream.
209  void emitStringTable(MCObjectStreamer &OS);
210
211  /// Emits the file checksum substream.
212  void emitFileChecksums(MCObjectStreamer &OS);
213
214  /// Emits the offset into the checksum table of the given file number.
215  void emitFileChecksumOffset(MCObjectStreamer &OS, unsigned FileNo);
216
217  /// Add something to the string table.  Returns the final string as well as
218  /// offset into the string table.
219  std::pair<StringRef, unsigned> addToStringTable(StringRef S);
220
221private:
222  /// Map from string to string table offset.
223  StringMap<unsigned> StringTable;
224
225  /// The fragment that ultimately holds our strings.
226  MCDataFragment *StrTabFragment = nullptr;
227  bool InsertedStrTabFragment = false;
228
229  MCDataFragment *getStringTableFragment();
230
231  /// Get a string table offset.
232  unsigned getStringTableOffset(StringRef S);
233
234  struct FileInfo {
235    unsigned StringTableOffset;
236
237    // Indicates if this FileInfo corresponds to an actual file, or hasn't been
238    // set yet.
239    bool Assigned = false;
240
241    uint8_t ChecksumKind;
242
243    ArrayRef<uint8_t> Checksum;
244
245    // Checksum offset stored as a symbol because it might be requested
246    // before it has been calculated, so a fixup may be needed.
247    MCSymbol *ChecksumTableOffset;
248  };
249
250  /// Array storing added file information.
251  SmallVector<FileInfo, 4> Files;
252
253  /// The offset of the first and last .cv_loc directive for a given function
254  /// id.
255  std::map<unsigned, std::pair<size_t, size_t>> MCCVLineStartStop;
256
257  /// A collection of MCCVLoc for each section.
258  std::vector<MCCVLoc> MCCVLines;
259
260  /// All known functions and inlined call sites, indexed by function id.
261  std::vector<MCCVFunctionInfo> Functions;
262
263  /// Indicate whether we have already laid out the checksum table addresses or
264  /// not.
265  bool ChecksumOffsetsAssigned = false;
266};
267
268} // end namespace llvm
269#endif
270