SourceLocation.h revision b7489d8129136437953d412e2a6cf0ef87f4a461 
1//===--- SourceLocation.h - Compact identifier for Source Files -*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file was developed by Chris Lattner and is distributed under
6// the University of Illinois Open Source License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10//  This file defines the SourceLocation class.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CLANG_SOURCELOCATION_H
15#define LLVM_CLANG_SOURCELOCATION_H
16
17#include <cassert>
18#include "llvm/Bitcode/SerializationFwd.h"
19
20namespace clang {
21
22/// SourceLocation - This is a carefully crafted 32-bit identifier that encodes
23/// a full include stack, line and column number information for a position in
24/// an input translation unit.
25class SourceLocation {
26  unsigned ID;
27public:
28  enum {
29    // FileID Layout:
30    // bit 31: 0 -> FileID, 1 -> MacroID (invalid for FileID)
31    //     30...17 -> FileID of source location, index into SourceManager table.
32    FileIDBits  = 14,
33    //      0...16 -> Index into the chunk of the specified FileID.
34    FilePosBits = 32-1-FileIDBits,
35
36    // MacroID Layout:
37    // bit 31: 1 -> MacroID, 0 -> FileID (invalid for MacroID)
38
39    // bit 30: 1 -> Start of macro expansion marker.
40    MacroStartOfExpansionBit = 30,
41    // bit 29: 1 -> End of macro expansion marker.
42    MacroEndOfExpansionBit = 29,
43    // bits 28...9 -> MacroID number.
44    MacroIDBits       = 20,
45    // bits 8...0  -> Macro Physical offset
46    MacroPhysOffsBits = 9,
47
48
49    // Useful constants.
50    ChunkSize = (1 << FilePosBits)
51  };
52
53  SourceLocation() : ID(0) {}  // 0 is an invalid FileID.
54
55  bool isFileID() const { return (ID >> 31) == 0; }
56  bool isMacroID() const { return (ID >> 31) != 0; }
57
58  /// isValid - Return true if this is a valid SourceLocation object.  Invalid
59  /// SourceLocations are often used when events have no corresponding location
60  /// in the source (e.g. a diagnostic is required for a command line option).
61  ///
62  bool isValid() const { return ID != 0; }
63  bool isInvalid() const { return ID == 0; }
64
65  static SourceLocation getFileLoc(unsigned FileID, unsigned FilePos) {
66    SourceLocation L;
67    // If a FilePos is larger than (1<<FilePosBits), the SourceManager makes
68    // enough consequtive FileIDs that we have one for each chunk.
69    if (FilePos >= ChunkSize) {
70      FileID += FilePos >> FilePosBits;
71      FilePos &= ChunkSize-1;
72    }
73
74    // FIXME: Find a way to handle out of FileID bits!  Maybe MaxFileID is an
75    // escape of some sort?
76    assert(FileID < (1 << FileIDBits) && "Out of fileid's");
77
78    L.ID = (FileID << FilePosBits) | FilePos;
79    return L;
80  }
81
82  static bool isValidMacroPhysOffs(int Val) {
83    if (Val >= 0)
84      return Val < (1 << (MacroPhysOffsBits-1));
85    return -Val < (1 << (MacroPhysOffsBits-1));
86  }
87
88  static SourceLocation getMacroLoc(unsigned MacroID, int PhysOffs,
89                                    bool isExpansionStart, bool isExpansionEnd){
90    assert(MacroID < (1 << MacroIDBits) && "Too many macros!");
91    assert(isValidMacroPhysOffs(PhysOffs) && "Physoffs too large!");
92
93    // Mask off sign bits.
94    PhysOffs &= (1 << MacroPhysOffsBits)-1;
95
96    SourceLocation L;
97    L.ID = (1 << 31) |
98           (isExpansionStart << MacroStartOfExpansionBit) |
99           (isExpansionEnd << MacroEndOfExpansionBit) |
100           (MacroID << MacroPhysOffsBits) |
101           PhysOffs;
102    return L;
103  }
104
105
106  /// getFileID - Return the file identifier for this SourceLocation.  This
107  /// FileID can be used with the SourceManager object to obtain an entire
108  /// include stack for a file position reference.
109  unsigned getFileID() const {
110    assert(isFileID() && "can't get the file id of a non-file sloc!");
111    return ID >> FilePosBits;
112  }
113
114  /// getRawFilePos - Return the byte offset from the start of the file-chunk
115  /// referred to by FileID.  This method should not be used to get the offset
116  /// from the start of the file, instead you should use
117  /// SourceManager::getFilePos.  This method will be incorrect for large files.
118  unsigned getRawFilePos() const {
119    assert(isFileID() && "can't get the file id of a non-file sloc!");
120    return ID & (ChunkSize-1);
121  }
122
123  unsigned getMacroID() const {
124    assert(isMacroID() && "Is not a macro id!");
125    return (ID >> MacroPhysOffsBits) & ((1 << MacroIDBits)-1);
126  }
127
128  int getMacroPhysOffs() const {
129    assert(isMacroID() && "Is not a macro id!");
130    int Val = ID & ((1 << MacroPhysOffsBits)-1);
131    // Sign extend it properly.
132    unsigned ShAmt = sizeof(int)*8 - MacroPhysOffsBits;
133    return (Val << ShAmt) >> ShAmt;
134  }
135
136  /// getFileLocWithOffset - Return a source location with the specified offset
137  /// from this file SourceLocation.
138  SourceLocation getFileLocWithOffset(int Offset) const {
139    unsigned FileID = getFileID();
140    Offset += getRawFilePos();
141    // Handle negative offsets correctly.
142    while (Offset < 0) {
143      --FileID;
144      Offset += ChunkSize;
145    }
146    return getFileLoc(FileID, Offset);
147  }
148
149  /// getRawEncoding - When a SourceLocation itself cannot be used, this returns
150  /// an (opaque) 32-bit integer encoding for it.  This should only be passed
151  /// to SourceLocation::getFromRawEncoding, it should not be inspected
152  /// directly.
153  unsigned getRawEncoding() const { return ID; }
154
155  /// getFromRawEncoding - Turn a raw encoding of a SourceLocation object into
156  /// a real SourceLocation.
157  static SourceLocation getFromRawEncoding(unsigned Encoding) {
158    SourceLocation X;
159    X.ID = Encoding;
160    return X;
161  }
162
163  /// Emit - Emit this SourceLocation object to Bitcode.
164  void Emit(llvm::Serializer& S) const;
165
166  /// ReadVal - Read a SourceLocation object from Bitcode.
167  static SourceLocation ReadVal(llvm::Deserializer& D);
168};
169
170inline bool operator==(const SourceLocation &LHS, const SourceLocation &RHS) {
171  return LHS.getRawEncoding() == RHS.getRawEncoding();
172}
173
174inline bool operator!=(const SourceLocation &LHS, const SourceLocation &RHS) {
175  return !(LHS == RHS);
176}
177
178/// SourceRange - a trival tuple used to represent a source range.
179class SourceRange {
180  SourceLocation B;
181  SourceLocation E;
182public:
183  SourceRange(): B(SourceLocation()), E(SourceLocation()) {}
184  SourceRange(SourceLocation loc) : B(loc), E(loc) {}
185  SourceRange(SourceLocation begin, SourceLocation end) : B(begin), E(end) {}
186
187  SourceLocation getBegin() const { return B; }
188  SourceLocation getEnd() const { return E; }
189
190  void setBegin(SourceLocation b) { B = b; }
191  void setEnd(SourceLocation e) { E = e; }
192
193  bool isValid() const { return B.isValid() && E.isValid(); }
194
195  /// Emit - Emit this SourceRange object to Bitcode.
196  void Emit(llvm::Serializer& S) const;
197
198  /// ReadVal - Read a SourceRange object from Bitcode.
199  static SourceRange ReadVal(llvm::Deserializer& D);
200};
201
202}  // end namespace clang
203
204#endif
205