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1 //===-- Archive.cpp - Generic LLVM archive functions ------------*- 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 file contains the implementation of the Archive and ArchiveMember
11 // classes that is common to both reading and writing archives..
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "ArchiveInternals.h"
16 #include "llvm/Bitcode/ReaderWriter.h"
17 #include "llvm/Module.h"
18 #include "llvm/Support/FileSystem.h"
19 #include "llvm/Support/MemoryBuffer.h"
20 #include "llvm/Support/Process.h"
21 #include "llvm/Support/system_error.h"
22 #include <memory>
23 #include <cstring>
24 using namespace llvm;
25 
26 // getMemberSize - compute the actual physical size of the file member as seen
27 // on disk. This isn't the size of member's payload. Use getSize() for that.
28 unsigned
getMemberSize() const29 ArchiveMember::getMemberSize() const {
30   // Basically its the file size plus the header size
31   unsigned result =  info.fileSize + sizeof(ArchiveMemberHeader);
32 
33   // If it has a long filename, include the name length
34   if (hasLongFilename())
35     result += path.str().length() + 1;
36 
37   // If its now odd lengthed, include the padding byte
38   if (result % 2 != 0 )
39     result++;
40 
41   return result;
42 }
43 
44 // This default constructor is only use by the ilist when it creates its
45 // sentry node. We give it specific static values to make it stand out a bit.
ArchiveMember()46 ArchiveMember::ArchiveMember()
47   : parent(0), path("--invalid--"), flags(0), data(0)
48 {
49   info.user = sys::Process::GetCurrentUserId();
50   info.group = sys::Process::GetCurrentGroupId();
51   info.mode = 0777;
52   info.fileSize = 0;
53   info.modTime = sys::TimeValue::now();
54 }
55 
56 // This is the constructor that the Archive class uses when it is building or
57 // reading an archive. It just defaults a few things and ensures the parent is
58 // set for the iplist. The Archive class fills in the ArchiveMember's data.
59 // This is required because correctly setting the data may depend on other
60 // things in the Archive.
ArchiveMember(Archive * PAR)61 ArchiveMember::ArchiveMember(Archive* PAR)
62   : parent(PAR), path(), flags(0), data(0)
63 {
64 }
65 
66 // This method allows an ArchiveMember to be replaced with the data for a
67 // different file, presumably as an update to the member. It also makes sure
68 // the flags are reset correctly.
replaceWith(const sys::Path & newFile,std::string * ErrMsg)69 bool ArchiveMember::replaceWith(const sys::Path& newFile, std::string* ErrMsg) {
70   bool Exists;
71   if (sys::fs::exists(newFile.str(), Exists) || !Exists) {
72     if (ErrMsg)
73       *ErrMsg = "Can not replace an archive member with a non-existent file";
74     return true;
75   }
76 
77   data = 0;
78   path = newFile;
79 
80   // SVR4 symbol tables have an empty name
81   if (path.str() == ARFILE_SVR4_SYMTAB_NAME)
82     flags |= SVR4SymbolTableFlag;
83   else
84     flags &= ~SVR4SymbolTableFlag;
85 
86   // BSD4.4 symbol tables have a special name
87   if (path.str() == ARFILE_BSD4_SYMTAB_NAME)
88     flags |= BSD4SymbolTableFlag;
89   else
90     flags &= ~BSD4SymbolTableFlag;
91 
92   // LLVM symbol tables have a very specific name
93   if (path.str() == ARFILE_LLVM_SYMTAB_NAME)
94     flags |= LLVMSymbolTableFlag;
95   else
96     flags &= ~LLVMSymbolTableFlag;
97 
98   // String table name
99   if (path.str() == ARFILE_STRTAB_NAME)
100     flags |= StringTableFlag;
101   else
102     flags &= ~StringTableFlag;
103 
104   // If it has a slash then it has a path
105   bool hasSlash = path.str().find('/') != std::string::npos;
106   if (hasSlash)
107     flags |= HasPathFlag;
108   else
109     flags &= ~HasPathFlag;
110 
111   // If it has a slash or its over 15 chars then its a long filename format
112   if (hasSlash || path.str().length() > 15)
113     flags |= HasLongFilenameFlag;
114   else
115     flags &= ~HasLongFilenameFlag;
116 
117   // Get the signature and status info
118   const char* signature = (const char*) data;
119   SmallString<4> magic;
120   if (!signature) {
121     sys::fs::get_magic(path.str(), magic.capacity(), magic);
122     signature = magic.c_str();
123     const sys::FileStatus *FSinfo = path.getFileStatus(false, ErrMsg);
124     if (FSinfo)
125       info = *FSinfo;
126     else
127       return true;
128   }
129 
130   // Determine what kind of file it is.
131   switch (sys::IdentifyFileType(signature,4)) {
132     case sys::Bitcode_FileType:
133       flags |= BitcodeFlag;
134       break;
135     default:
136       flags &= ~BitcodeFlag;
137       break;
138   }
139   return false;
140 }
141 
142 // Archive constructor - this is the only constructor that gets used for the
143 // Archive class. Everything else (default,copy) is deprecated. This just
144 // initializes and maps the file into memory, if requested.
Archive(const sys::Path & filename,LLVMContext & C)145 Archive::Archive(const sys::Path& filename, LLVMContext& C)
146   : archPath(filename), members(), mapfile(0), base(0), symTab(), strtab(),
147     symTabSize(0), firstFileOffset(0), modules(), foreignST(0), Context(C) {
148 }
149 
150 bool
mapToMemory(std::string * ErrMsg)151 Archive::mapToMemory(std::string* ErrMsg) {
152   OwningPtr<MemoryBuffer> File;
153   if (error_code ec = MemoryBuffer::getFile(archPath.c_str(), File)) {
154     if (ErrMsg)
155       *ErrMsg = ec.message();
156     return true;
157   }
158   mapfile = File.take();
159   base = mapfile->getBufferStart();
160   return false;
161 }
162 
cleanUpMemory()163 void Archive::cleanUpMemory() {
164   // Shutdown the file mapping
165   delete mapfile;
166   mapfile = 0;
167   base = 0;
168 
169   // Forget the entire symbol table
170   symTab.clear();
171   symTabSize = 0;
172 
173   firstFileOffset = 0;
174 
175   // Free the foreign symbol table member
176   if (foreignST) {
177     delete foreignST;
178     foreignST = 0;
179   }
180 
181   // Delete any Modules and ArchiveMember's we've allocated as a result of
182   // symbol table searches.
183   for (ModuleMap::iterator I=modules.begin(), E=modules.end(); I != E; ++I ) {
184     delete I->second.first;
185     delete I->second.second;
186   }
187 }
188 
189 // Archive destructor - just clean up memory
~Archive()190 Archive::~Archive() {
191   cleanUpMemory();
192 }
193 
194 
195 
getSymbols(Module * M,std::vector<std::string> & symbols)196 static void getSymbols(Module*M, std::vector<std::string>& symbols) {
197   // Loop over global variables
198   for (Module::global_iterator GI = M->global_begin(), GE=M->global_end(); GI != GE; ++GI)
199     if (!GI->isDeclaration() && !GI->hasLocalLinkage())
200       if (!GI->getName().empty())
201         symbols.push_back(GI->getName());
202 
203   // Loop over functions
204   for (Module::iterator FI = M->begin(), FE = M->end(); FI != FE; ++FI)
205     if (!FI->isDeclaration() && !FI->hasLocalLinkage())
206       if (!FI->getName().empty())
207         symbols.push_back(FI->getName());
208 
209   // Loop over aliases
210   for (Module::alias_iterator AI = M->alias_begin(), AE = M->alias_end();
211        AI != AE; ++AI) {
212     if (AI->hasName())
213       symbols.push_back(AI->getName());
214   }
215 }
216 
217 // Get just the externally visible defined symbols from the bitcode
GetBitcodeSymbols(const sys::Path & fName,LLVMContext & Context,std::vector<std::string> & symbols,std::string * ErrMsg)218 bool llvm::GetBitcodeSymbols(const sys::Path& fName,
219                              LLVMContext& Context,
220                              std::vector<std::string>& symbols,
221                              std::string* ErrMsg) {
222   OwningPtr<MemoryBuffer> Buffer;
223   if (error_code ec = MemoryBuffer::getFileOrSTDIN(fName.c_str(), Buffer)) {
224     if (ErrMsg) *ErrMsg = "Could not open file '" + fName.str() + "'" + ": "
225                         + ec.message();
226     return true;
227   }
228 
229   Module *M = ParseBitcodeFile(Buffer.get(), Context, ErrMsg);
230   if (!M)
231     return true;
232 
233   // Get the symbols
234   getSymbols(M, symbols);
235 
236   // Done with the module.
237   delete M;
238   return true;
239 }
240 
241 Module*
GetBitcodeSymbols(const char * BufPtr,unsigned Length,const std::string & ModuleID,LLVMContext & Context,std::vector<std::string> & symbols,std::string * ErrMsg)242 llvm::GetBitcodeSymbols(const char *BufPtr, unsigned Length,
243                         const std::string& ModuleID,
244                         LLVMContext& Context,
245                         std::vector<std::string>& symbols,
246                         std::string* ErrMsg) {
247   // Get the module.
248   OwningPtr<MemoryBuffer> Buffer(
249     MemoryBuffer::getMemBufferCopy(StringRef(BufPtr, Length),ModuleID.c_str()));
250 
251   Module *M = ParseBitcodeFile(Buffer.get(), Context, ErrMsg);
252   if (!M)
253     return 0;
254 
255   // Get the symbols
256   getSymbols(M, symbols);
257 
258   // Done with the module. Note that it's the caller's responsibility to delete
259   // the Module.
260   return M;
261 }
262