diff --git a/llvm/include/llvm/Support/DynamicLibrary.h b/llvm/include/llvm/Support/DynamicLibrary.h index 95d5ba281e2250..0771606a75f56e 100644 --- a/llvm/include/llvm/Support/DynamicLibrary.h +++ b/llvm/include/llvm/Support/DynamicLibrary.h @@ -21,110 +21,129 @@ class StringRef; namespace sys { - /// This class provides a portable interface to dynamic libraries which also - /// might be known as shared libraries, shared objects, dynamic shared - /// objects, or dynamic link libraries. Regardless of the terminology or the - /// operating system interface, this class provides a portable interface that - /// allows dynamic libraries to be loaded and searched for externally - /// defined symbols. This is typically used to provide "plug-in" support. - /// It also allows for symbols to be defined which don't live in any library, - /// but rather the main program itself, useful on Windows where the main - /// executable cannot be searched. +/// This class provides a portable interface to dynamic libraries which also +/// might be known as shared libraries, shared objects, dynamic shared +/// objects, or dynamic link libraries. Regardless of the terminology or the +/// operating system interface, this class provides a portable interface that +/// allows dynamic libraries to be loaded and searched for externally +/// defined symbols. This is typically used to provide "plug-in" support. +/// It also allows for symbols to be defined which don't live in any library, +/// but rather the main program itself, useful on Windows where the main +/// executable cannot be searched. +class DynamicLibrary { + // Placeholder whose address represents an invalid library. + // We use this instead of NULL or a pointer-int pair because the OS library + // might define 0 or 1 to be "special" handles, such as "search all". + static char Invalid; + + // Opaque data used to interface with OS-specific dynamic library handling. + void *Data; + +public: + explicit DynamicLibrary(void *data = &Invalid) : Data(data) {} + + /// Returns true if the object refers to a valid library. + bool isValid() const { return Data != &Invalid; } + + /// Searches through the library for the symbol \p symbolName. If it is + /// found, the address of that symbol is returned. If not, NULL is returned. + /// Note that NULL will also be returned if the library failed to load. + /// Use isValid() to distinguish these cases if it is important. + /// Note that this will \e not search symbols explicitly registered by + /// AddSymbol(). + void *getAddressOfSymbol(const char *symbolName); + + /// This function permanently loads the dynamic library at the given path + /// using the library load operation from the host operating system. The + /// library instance will only be closed when global destructors run, and + /// there is no guarantee when the library will be unloaded. /// - /// Note: there is currently no interface for temporarily loading a library, - /// or for unloading libraries when the LLVM library is unloaded. - class DynamicLibrary { - // Placeholder whose address represents an invalid library. - // We use this instead of NULL or a pointer-int pair because the OS library - // might define 0 or 1 to be "special" handles, such as "search all". - static char Invalid; - - // Opaque data used to interface with OS-specific dynamic library handling. - void *Data; - - public: - explicit DynamicLibrary(void *data = &Invalid) : Data(data) {} - - /// Returns true if the object refers to a valid library. - bool isValid() const { return Data != &Invalid; } - - /// Searches through the library for the symbol \p symbolName. If it is - /// found, the address of that symbol is returned. If not, NULL is returned. - /// Note that NULL will also be returned if the library failed to load. - /// Use isValid() to distinguish these cases if it is important. - /// Note that this will \e not search symbols explicitly registered by - /// AddSymbol(). - void *getAddressOfSymbol(const char *symbolName); - - /// This function permanently loads the dynamic library at the given path. - /// The library will only be unloaded when llvm_shutdown() is called. - /// This returns a valid DynamicLibrary instance on success and an invalid - /// instance on failure (see isValid()). \p *errMsg will only be modified - /// if the library fails to load. - /// - /// It is safe to call this function multiple times for the same library. - /// Open a dynamic library permanently. - static DynamicLibrary getPermanentLibrary(const char *filename, - std::string *errMsg = nullptr); - - /// Registers an externally loaded library. The library will be unloaded - /// when the program terminates. - /// - /// It is safe to call this function multiple times for the same library, - /// though ownership is only taken if there was no error. - /// - /// \returns An empty \p DynamicLibrary if the library was already loaded. - static DynamicLibrary addPermanentLibrary(void *handle, - std::string *errMsg = nullptr); - - /// This function permanently loads the dynamic library at the given path. - /// Use this instead of getPermanentLibrary() when you won't need to get - /// symbols from the library itself. - /// - /// It is safe to call this function multiple times for the same library. - static bool LoadLibraryPermanently(const char *Filename, - std::string *ErrMsg = nullptr) { - return !getPermanentLibrary(Filename, ErrMsg).isValid(); - } - - enum SearchOrdering { - /// SO_Linker - Search as a call to dlsym(dlopen(NULL)) would when - /// DynamicLibrary::getPermanentLibrary(NULL) has been called or - /// search the list of explcitly loaded symbols if not. - SO_Linker, - /// SO_LoadedFirst - Search all loaded libraries, then as SO_Linker would. - SO_LoadedFirst, - /// SO_LoadedLast - Search as SO_Linker would, then loaded libraries. - /// Only useful to search if libraries with RTLD_LOCAL have been added. - SO_LoadedLast, - /// SO_LoadOrder - Or this in to search libraries in the ordered loaded. - /// The default bahaviour is to search loaded libraries in reverse. - SO_LoadOrder = 4 - }; - static SearchOrdering SearchOrder; // = SO_Linker - - /// This function will search through all previously loaded dynamic - /// libraries for the symbol \p symbolName. If it is found, the address of - /// that symbol is returned. If not, null is returned. Note that this will - /// search permanently loaded libraries (getPermanentLibrary()) as well - /// as explicitly registered symbols (AddSymbol()). - /// @throws std::string on error. - /// Search through libraries for address of a symbol - static void *SearchForAddressOfSymbol(const char *symbolName); - - /// Convenience function for C++ophiles. - static void *SearchForAddressOfSymbol(const std::string &symbolName) { - return SearchForAddressOfSymbol(symbolName.c_str()); - } - - /// This functions permanently adds the symbol \p symbolName with the - /// value \p symbolValue. These symbols are searched before any - /// libraries. - /// Add searchable symbol/value pair. - static void AddSymbol(StringRef symbolName, void *symbolValue); - - class HandleSet; + /// This returns a valid DynamicLibrary instance on success and an invalid + /// instance on failure (see isValid()). \p *errMsg will only be modified if + /// the library fails to load. + /// + /// It is safe to call this function multiple times for the same library. + /// Open a dynamic library permanently. + static DynamicLibrary getPermanentLibrary(const char *filename, + std::string *errMsg = nullptr); + + /// Registers an externally loaded library. The library will be unloaded + /// when the program terminates. + /// + /// It is safe to call this function multiple times for the same library, + /// though ownership is only taken if there was no error. + static DynamicLibrary addPermanentLibrary(void *handle, + std::string *errMsg = nullptr); + + /// This function permanently loads the dynamic library at the given path. + /// Use this instead of getPermanentLibrary() when you won't need to get + /// symbols from the library itself. + /// + /// It is safe to call this function multiple times for the same library. + static bool LoadLibraryPermanently(const char *Filename, + std::string *ErrMsg = nullptr) { + return !getPermanentLibrary(Filename, ErrMsg).isValid(); + } + + /// This function loads the dynamic library at the given path, using the + /// library load operation from the host operating system. The library + /// instance will be closed when closeLibrary is called or global destructors + /// are run, but there is no guarantee when the library will be unloaded. + /// + /// This returns a valid DynamicLibrary instance on success and an invalid + /// instance on failure (see isValid()). \p *Err will only be modified if the + /// library fails to load. + /// + /// It is safe to call this function multiple times for the same library. + static DynamicLibrary getLibrary(const char *FileName, + std::string *Err = nullptr); + + /// This function closes the dynamic library at the given path, using the + /// library close operation of the host operating system, and there is no + /// guarantee if or when this will cause the the library to be unloaded. + /// + /// This function should be called only if the library was loaded using the + /// getLibrary() function. + static void closeLibrary(DynamicLibrary &Lib); + + enum SearchOrdering { + /// SO_Linker - Search as a call to dlsym(dlopen(NULL)) would when + /// DynamicLibrary::getPermanentLibrary(NULL) has been called or + /// search the list of explcitly loaded symbols if not. + SO_Linker, + /// SO_LoadedFirst - Search all loaded libraries, then as SO_Linker would. + SO_LoadedFirst, + /// SO_LoadedLast - Search as SO_Linker would, then loaded libraries. + /// Only useful to search if libraries with RTLD_LOCAL have been added. + SO_LoadedLast, + /// SO_LoadOrder - Or this in to search libraries in the ordered loaded. + /// The default bahaviour is to search loaded libraries in reverse. + SO_LoadOrder = 4 }; + static SearchOrdering SearchOrder; // = SO_Linker + + /// This function will search through all previously loaded dynamic + /// libraries for the symbol \p symbolName. If it is found, the address of + /// that symbol is returned. If not, null is returned. Note that this will + /// search permanently loaded libraries (getPermanentLibrary()) as well + /// as explicitly registered symbols (AddSymbol()). + /// @throws std::string on error. + /// Search through libraries for address of a symbol + static void *SearchForAddressOfSymbol(const char *symbolName); + + /// Convenience function for C++ophiles. + static void *SearchForAddressOfSymbol(const std::string &symbolName) { + return SearchForAddressOfSymbol(symbolName.c_str()); + } + + /// This functions permanently adds the symbol \p symbolName with the + /// value \p symbolValue. These symbols are searched before any + /// libraries. + /// Add searchable symbol/value pair. + static void AddSymbol(StringRef symbolName, void *symbolValue); + + class HandleSet; +}; } // End sys namespace } // End llvm namespace diff --git a/llvm/lib/Support/DynamicLibrary.cpp b/llvm/lib/Support/DynamicLibrary.cpp index 319fbc59d43bb0..531c035ab92666 100644 --- a/llvm/lib/Support/DynamicLibrary.cpp +++ b/llvm/lib/Support/DynamicLibrary.cpp @@ -41,13 +41,16 @@ class DynamicLibrary::HandleSet { return Handle == Process || Find(Handle) != Handles.end(); } - bool AddLibrary(void *Handle, bool IsProcess = false, bool CanClose = true) { + bool AddLibrary(void *Handle, bool IsProcess = false, bool CanClose = true, + bool AllowDuplicates = false) { #ifdef _WIN32 assert((Handle == this ? IsProcess : !IsProcess) && "Bad Handle."); #endif + assert((!AllowDuplicates || !CanClose) && + "CanClose must be false if AllowDuplicates is true."); if (LLVM_LIKELY(!IsProcess)) { - if (Find(Handle) != Handles.end()) { + if (!AllowDuplicates && Find(Handle) != Handles.end()) { if (CanClose) DLClose(Handle); return false; @@ -67,6 +70,14 @@ class DynamicLibrary::HandleSet { return true; } + void CloseLibrary(void *Handle) { + DLClose(Handle); + HandleList::iterator it = Find(Handle); + if (it != Handles.end()) { + Handles.erase(it); + } + } + void *LibLookup(const char *Symbol, DynamicLibrary::SearchOrdering Order) { if (Order & SO_LoadOrder) { for (void *Handle : Handles) { @@ -111,9 +122,10 @@ struct Globals { // Collection of symbol name/value pairs to be searched prior to any // libraries. llvm::StringMap ExplicitSymbols; - // Collection of known library handles. + // Collections of known library handles. DynamicLibrary::HandleSet OpenedHandles; - // Lock for ExplicitSymbols and OpenedHandles. + DynamicLibrary::HandleSet OpenedTemporaryHandles; + // Lock for ExplicitSymbols, OpenedHandles, and OpenedTemporaryHandles. llvm::sys::SmartMutex SymbolsMutex; }; @@ -174,6 +186,29 @@ DynamicLibrary DynamicLibrary::addPermanentLibrary(void *Handle, return DynamicLibrary(Handle); } +DynamicLibrary DynamicLibrary::getLibrary(const char *FileName, + std::string *Err) { + assert(FileName && "Use getPermanentLibrary() for opening process handle"); + void *Handle = HandleSet::DLOpen(FileName, Err); + if (Handle != &Invalid) { + auto &G = getGlobals(); + SmartScopedLock Lock(G.SymbolsMutex); + G.OpenedTemporaryHandles.AddLibrary(Handle, /*IsProcess*/ false, + /*CanClose*/ false, + /*AllowDuplicates*/ true); + } + return DynamicLibrary(Handle); +} + +void DynamicLibrary::closeLibrary(DynamicLibrary &Lib) { + auto &G = getGlobals(); + SmartScopedLock Lock(G.SymbolsMutex); + if (Lib.isValid()) { + G.OpenedTemporaryHandles.CloseLibrary(Lib.Data); + Lib.Data = &Invalid; + } +} + void *DynamicLibrary::getAddressOfSymbol(const char *SymbolName) { if (!isValid()) return nullptr; @@ -194,6 +229,8 @@ void *DynamicLibrary::SearchForAddressOfSymbol(const char *SymbolName) { // Now search the libraries. if (void *Ptr = G.OpenedHandles.Lookup(SymbolName, SearchOrder)) return Ptr; + if (void *Ptr = G.OpenedTemporaryHandles.Lookup(SymbolName, SearchOrder)) + return Ptr; } return llvm::SearchForAddressOfSpecialSymbol(SymbolName);