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1 //===- SourceMgr.cpp - Manager for Simple Source Buffers & Diagnostics ----===//
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 implements the SourceMgr class.  This class is used as a simple
11 // substrate for diagnostics, #include handling, and other low level things for
12 // simple parsers.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #include "llvm/ADT/Twine.h"
17 #include "llvm/Support/SourceMgr.h"
18 #include "llvm/Support/MemoryBuffer.h"
19 #include "llvm/ADT/OwningPtr.h"
20 #include "llvm/Support/raw_ostream.h"
21 #include "llvm/Support/system_error.h"
22 using namespace llvm;
23 
24 namespace {
25   struct LineNoCacheTy {
26     int LastQueryBufferID;
27     const char *LastQuery;
28     unsigned LineNoOfQuery;
29   };
30 }
31 
getCache(void * Ptr)32 static LineNoCacheTy *getCache(void *Ptr) {
33   return (LineNoCacheTy*)Ptr;
34 }
35 
36 
~SourceMgr()37 SourceMgr::~SourceMgr() {
38   // Delete the line # cache if allocated.
39   if (LineNoCacheTy *Cache = getCache(LineNoCache))
40     delete Cache;
41 
42   while (!Buffers.empty()) {
43     delete Buffers.back().Buffer;
44     Buffers.pop_back();
45   }
46 }
47 
48 /// AddIncludeFile - Search for a file with the specified name in the current
49 /// directory or in one of the IncludeDirs.  If no file is found, this returns
50 /// ~0, otherwise it returns the buffer ID of the stacked file.
AddIncludeFile(const std::string & Filename,SMLoc IncludeLoc,std::string & IncludedFile)51 unsigned SourceMgr::AddIncludeFile(const std::string &Filename,
52                                    SMLoc IncludeLoc,
53                                    std::string &IncludedFile) {
54   OwningPtr<MemoryBuffer> NewBuf;
55   IncludedFile = Filename;
56   MemoryBuffer::getFile(IncludedFile.c_str(), NewBuf);
57 
58   // If the file didn't exist directly, see if it's in an include path.
59   for (unsigned i = 0, e = IncludeDirectories.size(); i != e && !NewBuf; ++i) {
60     IncludedFile = IncludeDirectories[i] + "/" + Filename;
61     MemoryBuffer::getFile(IncludedFile.c_str(), NewBuf);
62   }
63 
64   if (NewBuf == 0) return ~0U;
65 
66   return AddNewSourceBuffer(NewBuf.take(), IncludeLoc);
67 }
68 
69 
70 /// FindBufferContainingLoc - Return the ID of the buffer containing the
71 /// specified location, returning -1 if not found.
FindBufferContainingLoc(SMLoc Loc) const72 int SourceMgr::FindBufferContainingLoc(SMLoc Loc) const {
73   for (unsigned i = 0, e = Buffers.size(); i != e; ++i)
74     if (Loc.getPointer() >= Buffers[i].Buffer->getBufferStart() &&
75         // Use <= here so that a pointer to the null at the end of the buffer
76         // is included as part of the buffer.
77         Loc.getPointer() <= Buffers[i].Buffer->getBufferEnd())
78       return i;
79   return -1;
80 }
81 
82 /// FindLineNumber - Find the line number for the specified location in the
83 /// specified file.  This is not a fast method.
FindLineNumber(SMLoc Loc,int BufferID) const84 unsigned SourceMgr::FindLineNumber(SMLoc Loc, int BufferID) const {
85   if (BufferID == -1) BufferID = FindBufferContainingLoc(Loc);
86   assert(BufferID != -1 && "Invalid Location!");
87 
88   MemoryBuffer *Buff = getBufferInfo(BufferID).Buffer;
89 
90   // Count the number of \n's between the start of the file and the specified
91   // location.
92   unsigned LineNo = 1;
93 
94   const char *Ptr = Buff->getBufferStart();
95 
96   // If we have a line number cache, and if the query is to a later point in the
97   // same file, start searching from the last query location.  This optimizes
98   // for the case when multiple diagnostics come out of one file in order.
99   if (LineNoCacheTy *Cache = getCache(LineNoCache))
100     if (Cache->LastQueryBufferID == BufferID &&
101         Cache->LastQuery <= Loc.getPointer()) {
102       Ptr = Cache->LastQuery;
103       LineNo = Cache->LineNoOfQuery;
104     }
105 
106   // Scan for the location being queried, keeping track of the number of lines
107   // we see.
108   for (; SMLoc::getFromPointer(Ptr) != Loc; ++Ptr)
109     if (*Ptr == '\n') ++LineNo;
110 
111 
112   // Allocate the line number cache if it doesn't exist.
113   if (LineNoCache == 0)
114     LineNoCache = new LineNoCacheTy();
115 
116   // Update the line # cache.
117   LineNoCacheTy &Cache = *getCache(LineNoCache);
118   Cache.LastQueryBufferID = BufferID;
119   Cache.LastQuery = Ptr;
120   Cache.LineNoOfQuery = LineNo;
121   return LineNo;
122 }
123 
PrintIncludeStack(SMLoc IncludeLoc,raw_ostream & OS) const124 void SourceMgr::PrintIncludeStack(SMLoc IncludeLoc, raw_ostream &OS) const {
125   if (IncludeLoc == SMLoc()) return;  // Top of stack.
126 
127   int CurBuf = FindBufferContainingLoc(IncludeLoc);
128   assert(CurBuf != -1 && "Invalid or unspecified location!");
129 
130   PrintIncludeStack(getBufferInfo(CurBuf).IncludeLoc, OS);
131 
132   OS << "Included from "
133      << getBufferInfo(CurBuf).Buffer->getBufferIdentifier()
134      << ":" << FindLineNumber(IncludeLoc, CurBuf) << ":\n";
135 }
136 
137 
138 /// GetMessage - Return an SMDiagnostic at the specified location with the
139 /// specified string.
140 ///
141 /// @param Type - If non-null, the kind of message (e.g., "error") which is
142 /// prefixed to the message.
GetMessage(SMLoc Loc,const Twine & Msg,const char * Type,bool ShowLine) const143 SMDiagnostic SourceMgr::GetMessage(SMLoc Loc, const Twine &Msg,
144                                    const char *Type, bool ShowLine) const {
145 
146   // First thing to do: find the current buffer containing the specified
147   // location.
148   int CurBuf = FindBufferContainingLoc(Loc);
149   assert(CurBuf != -1 && "Invalid or unspecified location!");
150 
151   MemoryBuffer *CurMB = getBufferInfo(CurBuf).Buffer;
152 
153   // Scan backward to find the start of the line.
154   const char *LineStart = Loc.getPointer();
155   while (LineStart != CurMB->getBufferStart() &&
156          LineStart[-1] != '\n' && LineStart[-1] != '\r')
157     --LineStart;
158 
159   std::string LineStr;
160   if (ShowLine) {
161     // Get the end of the line.
162     const char *LineEnd = Loc.getPointer();
163     while (LineEnd != CurMB->getBufferEnd() &&
164            LineEnd[0] != '\n' && LineEnd[0] != '\r')
165       ++LineEnd;
166     LineStr = std::string(LineStart, LineEnd);
167   }
168 
169   std::string PrintedMsg;
170   raw_string_ostream OS(PrintedMsg);
171   if (Type)
172     OS << Type << ": ";
173   OS << Msg;
174 
175   return SMDiagnostic(*this, Loc,
176                       CurMB->getBufferIdentifier(), FindLineNumber(Loc, CurBuf),
177                       Loc.getPointer()-LineStart, OS.str(),
178                       LineStr, ShowLine);
179 }
180 
PrintMessage(SMLoc Loc,const Twine & Msg,const char * Type,bool ShowLine) const181 void SourceMgr::PrintMessage(SMLoc Loc, const Twine &Msg,
182                              const char *Type, bool ShowLine) const {
183   // Report the message with the diagnostic handler if present.
184   if (DiagHandler) {
185     DiagHandler(GetMessage(Loc, Msg, Type, ShowLine), DiagContext);
186     return;
187   }
188 
189   raw_ostream &OS = errs();
190 
191   int CurBuf = FindBufferContainingLoc(Loc);
192   assert(CurBuf != -1 && "Invalid or unspecified location!");
193   PrintIncludeStack(getBufferInfo(CurBuf).IncludeLoc, OS);
194 
195   GetMessage(Loc, Msg, Type, ShowLine).Print(0, OS);
196 }
197 
198 //===----------------------------------------------------------------------===//
199 // SMDiagnostic Implementation
200 //===----------------------------------------------------------------------===//
201 
Print(const char * ProgName,raw_ostream & S) const202 void SMDiagnostic::Print(const char *ProgName, raw_ostream &S) const {
203   if (ProgName && ProgName[0])
204     S << ProgName << ": ";
205 
206   if (!Filename.empty()) {
207     if (Filename == "-")
208       S << "<stdin>";
209     else
210       S << Filename;
211 
212     if (LineNo != -1) {
213       S << ':' << LineNo;
214       if (ColumnNo != -1)
215         S << ':' << (ColumnNo+1);
216     }
217     S << ": ";
218   }
219 
220   S << Message << '\n';
221 
222   if (LineNo != -1 && ColumnNo != -1 && ShowLine) {
223     S << LineContents << '\n';
224 
225     // Print out spaces/tabs before the caret.
226     for (unsigned i = 0; i != unsigned(ColumnNo); ++i)
227       S << (LineContents[i] == '\t' ? '\t' : ' ');
228     S << "^\n";
229   }
230 }
231 
232 
233