Path.cpp revision 1f6efa3996dd1929fbc129203ce5009b620e6969 
1//===-- Path.cpp - Implement OS Path Concept --------------------*- 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 header file implements the operating system Path concept.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/Support/Path.h"
15#include "llvm/Config/config.h"
16#include <cassert>
17#include <cstring>
18#include <ostream>
19using namespace llvm;
20using namespace sys;
21
22//===----------------------------------------------------------------------===//
23//=== WARNING: Implementation here must contain only TRULY operating system
24//===          independent code.
25//===----------------------------------------------------------------------===//
26
27bool Path::operator==(const Path &that) const {
28  return path == that.path;
29}
30
31bool Path::operator<(const Path& that) const {
32  return path < that.path;
33}
34
35Path
36Path::GetLLVMConfigDir() {
37  Path result;
38#ifdef LLVM_ETCDIR
39  if (result.set(LLVM_ETCDIR))
40    return result;
41#endif
42  return GetLLVMDefaultConfigDir();
43}
44
45LLVMFileType
46sys::IdentifyFileType(const char *magic, unsigned length) {
47  assert(magic && "Invalid magic number string");
48  assert(length >=4 && "Invalid magic number length");
49  switch ((unsigned char)magic[0]) {
50    case 0xDE:  // 0x0B17C0DE = BC wraper
51      if (magic[1] == (char)0xC0 && magic[2] == (char)0x17 &&
52          magic[3] == (char)0x0B)
53        return Bitcode_FileType;
54      break;
55    case 'B':
56      if (magic[1] == 'C' && magic[2] == (char)0xC0 && magic[3] == (char)0xDE)
57        return Bitcode_FileType;
58      break;
59    case '!':
60      if (length >= 8)
61        if (memcmp(magic,"!<arch>\n",8) == 0)
62          return Archive_FileType;
63      break;
64
65    case '\177':
66      if (magic[1] == 'E' && magic[2] == 'L' && magic[3] == 'F') {
67        if (length >= 18 && magic[17] == 0)
68          switch (magic[16]) {
69            default: break;
70            case 1: return ELF_Relocatable_FileType;
71            case 2: return ELF_Executable_FileType;
72            case 3: return ELF_SharedObject_FileType;
73            case 4: return ELF_Core_FileType;
74          }
75      }
76      break;
77
78    case 0xCA:
79      if (magic[1] == char(0xFE) && magic[2] == char(0xBA) &&
80          magic[3] == char(0xBE)) {
81        // This is complicated by an overlap with Java class files.
82        // See the Mach-O section in /usr/share/file/magic for details.
83        if (length >= 8 && magic[7] < 43)
84          // FIXME: Universal Binary of any type.
85          return Mach_O_DynamicallyLinkedSharedLib_FileType;
86      }
87      break;
88
89    case 0xFE:
90    case 0xCE: {
91      uint16_t type = 0;
92      if (magic[0] == char(0xFE) && magic[1] == char(0xED) &&
93          magic[2] == char(0xFA) && magic[3] == char(0xCE)) {
94        /* Native endian */
95        if (length >= 16) type = magic[14] << 8 | magic[15];
96      } else if (magic[0] == char(0xCE) && magic[1] == char(0xFA) &&
97                 magic[2] == char(0xED) && magic[3] == char(0xFE)) {
98        /* Reverse endian */
99        if (length >= 14) type = magic[13] << 8 | magic[12];
100      }
101      switch (type) {
102        default: break;
103        case 1: return Mach_O_Object_FileType;
104        case 2: return Mach_O_Executable_FileType;
105        case 3: return Mach_O_FixedVirtualMemorySharedLib_FileType;
106        case 4: return Mach_O_Core_FileType;
107        case 5: return Mach_O_PreloadExecutable_FileType;
108        case 6: return Mach_O_DynamicallyLinkedSharedLib_FileType;
109        case 7: return Mach_O_DynamicLinker_FileType;
110        case 8: return Mach_O_Bundle_FileType;
111        case 9: return Mach_O_DynamicallyLinkedSharedLibStub_FileType;
112        case 10: break; // FIXME: MH_DSYM companion file with only debug.
113      }
114      break;
115    }
116    case 0xF0: // PowerPC Windows
117    case 0x83: // Alpha 32-bit
118    case 0x84: // Alpha 64-bit
119    case 0x66: // MPS R4000 Windows
120    case 0x50: // mc68K
121    case 0x4c: // 80386 Windows
122      if (magic[1] == 0x01)
123        return COFF_FileType;
124
125    case 0x90: // PA-RISC Windows
126    case 0x68: // mc68K Windows
127      if (magic[1] == 0x02)
128        return COFF_FileType;
129      break;
130    case 0x64: // x86-64 Windows.
131      if (magic[1] == char(0x86))
132        return COFF_FileType;
133      break;
134
135    default:
136      break;
137  }
138  return Unknown_FileType;
139}
140
141bool
142Path::isArchive() const {
143  return hasMagicNumber("!<arch>\012");
144}
145
146bool
147Path::isDynamicLibrary() const {
148  std::string Magic;
149  if (getMagicNumber(Magic, 64))
150    switch (IdentifyFileType(Magic.c_str(),
151                             static_cast<unsigned>(Magic.length()))) {
152      default: return false;
153      case Mach_O_FixedVirtualMemorySharedLib_FileType:
154      case Mach_O_DynamicallyLinkedSharedLib_FileType:
155      case Mach_O_DynamicallyLinkedSharedLibStub_FileType:
156      case ELF_SharedObject_FileType:
157      case COFF_FileType:  return true;
158    }
159
160  return false;
161}
162
163bool
164Path::isObjectFile() const {
165  std::string Magic;
166  if (getMagicNumber(Magic, 64))
167    if (IdentifyFileType(Magic.c_str(),
168                         static_cast<unsigned>(Magic.length()))
169        != Unknown_FileType) {
170      // Everything in LLVMFileType is currently an object file.
171      return true;
172    }
173
174  return false;
175}
176
177Path
178Path::FindLibrary(std::string& name) {
179  std::vector<sys::Path> LibPaths;
180  GetSystemLibraryPaths(LibPaths);
181  for (unsigned i = 0; i < LibPaths.size(); ++i) {
182    sys::Path FullPath(LibPaths[i]);
183    FullPath.appendComponent("lib" + name + LTDL_SHLIB_EXT);
184    if (FullPath.isDynamicLibrary())
185      return FullPath;
186    FullPath.eraseSuffix();
187    FullPath.appendSuffix("a");
188    if (FullPath.isArchive())
189      return FullPath;
190  }
191  return sys::Path();
192}
193
194StringRef Path::GetDLLSuffix() {
195  return &(LTDL_SHLIB_EXT[1]);
196}
197
198bool
199Path::appendSuffix(StringRef suffix) {
200  if (!suffix.empty()) {
201    std::string save(path);
202    path.append(".");
203    path.append(suffix);
204    if (!isValid()) {
205      path = save;
206      return false;
207    }
208  }
209
210  return true;
211}
212
213bool
214Path::isBitcodeFile() const {
215  std::string actualMagic;
216  if (!getMagicNumber(actualMagic, 4))
217    return false;
218  LLVMFileType FT =
219    IdentifyFileType(actualMagic.c_str(),
220                     static_cast<unsigned>(actualMagic.length()));
221  return FT == Bitcode_FileType;
222}
223
224bool Path::hasMagicNumber(StringRef Magic) const {
225  std::string actualMagic;
226  if (getMagicNumber(actualMagic, static_cast<unsigned>(Magic.size())))
227    return Magic == actualMagic;
228  return false;
229}
230
231static void getPathList(const char*path, std::vector<Path>& Paths) {
232  const char* at = path;
233  const char* delim = strchr(at, PathSeparator);
234  Path tmpPath;
235  while (delim != 0) {
236    std::string tmp(at, size_t(delim-at));
237    if (tmpPath.set(tmp))
238      if (tmpPath.canRead())
239        Paths.push_back(tmpPath);
240    at = delim + 1;
241    delim = strchr(at, PathSeparator);
242  }
243
244  if (*at != 0)
245    if (tmpPath.set(std::string(at)))
246      if (tmpPath.canRead())
247        Paths.push_back(tmpPath);
248}
249
250static StringRef getDirnameCharSep(StringRef path, const char *Sep) {
251  assert(Sep[0] != '\0' && Sep[1] == '\0' &&
252         "Sep must be a 1-character string literal.");
253  if (path.empty())
254    return ".";
255
256  // If the path is all slashes, return a single slash.
257  // Otherwise, remove all trailing slashes.
258
259  signed pos = static_cast<signed>(path.size()) - 1;
260
261  while (pos >= 0 && path[pos] == Sep[0])
262    --pos;
263
264  if (pos < 0)
265    return path[0] == Sep[0] ? Sep : ".";
266
267  // Any slashes left?
268  signed i = 0;
269
270  while (i < pos && path[i] != Sep[0])
271    ++i;
272
273  if (i == pos) // No slashes?  Return "."
274    return ".";
275
276  // There is at least one slash left.  Remove all trailing non-slashes.
277  while (pos >= 0 && path[pos] != Sep[0])
278    --pos;
279
280  // Remove any trailing slashes.
281  while (pos >= 0 && path[pos] == Sep[0])
282    --pos;
283
284  if (pos < 0)
285    return path[0] == Sep[0] ? Sep : ".";
286
287  return path.substr(0, pos+1);
288}
289
290// Include the truly platform-specific parts of this class.
291#if defined(LLVM_ON_UNIX)
292#include "Unix/Path.inc"
293#endif
294#if defined(LLVM_ON_WIN32)
295#include "Windows/Path.inc"
296#endif
297