diff --git a/include/llvm/System/DynamicLibrary.h b/include/llvm/System/DynamicLibrary.h index 5edbfd6f22f..1aea0460a22 100644 --- a/include/llvm/System/DynamicLibrary.h +++ b/include/llvm/System/DynamicLibrary.h @@ -26,6 +26,9 @@ namespace sys { /// operating system interface, this class provides a portable interface that /// allows dynamic libraries to be loaded and 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. /// @since 1.4 /// @brief Portable dynamic library abstraction. class DynamicLibrary { @@ -81,6 +84,17 @@ namespace sys { 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. + /// @brief Add searchable symbol/value pair. + static void AddSymbol(const char* symbolName, void *symbolValue); + + /// @brief Convenience function for C++ophiles. + static void AddSymbol(const std::string& symbolName, void *symbolValue) { + AddSymbol(symbolName.c_str(), symbolValue); + } + /// @} /// @name Accessors /// @{ diff --git a/lib/System/DynamicLibrary.cpp b/lib/System/DynamicLibrary.cpp index 18894cbc87d..0c179fc2f7e 100644 --- a/lib/System/DynamicLibrary.cpp +++ b/lib/System/DynamicLibrary.cpp @@ -13,6 +13,14 @@ #include "llvm/System/DynamicLibrary.h" #include "llvm/Config/config.h" +#include + +// Collection of symbol name/value pairs to be searched prior to any libraries. +static std::map g_symbols; + +void llvm::sys::DynamicLibrary::AddSymbol(const char* symbolName, void *symbolValue) { + g_symbols[symbolName] = symbolValue; +} // It is not possible to use ltdl.c on VC++ builds as the terms of its LGPL // license and special exception would cause all of LLVM to be placed under @@ -107,6 +115,13 @@ void DynamicLibrary::LoadLibraryPermanently(const char* filename) { void* DynamicLibrary::SearchForAddressOfSymbol(const char* symbolName) { check_ltdl_initialization(); + + // First check symbols added via AddSymbol(). + std::map::iterator I = g_symbols.find(symbolName); + if (I != g_symbols.end()) + return I->second; + + // Now search the libraries. for (std::vector::iterator I = OpenedHandles.begin(), E = OpenedHandles.end(); I != E; ++I) { lt_ptr ptr = lt_dlsym(*I, symbolName); diff --git a/lib/System/Win32/DynamicLibrary.inc b/lib/System/Win32/DynamicLibrary.inc index 1492138682f..310d3dc8359 100644 --- a/lib/System/Win32/DynamicLibrary.inc +++ b/lib/System/Win32/DynamicLibrary.inc @@ -107,6 +107,12 @@ void DynamicLibrary::LoadLibraryPermanently(const char* filename) { } void* DynamicLibrary::SearchForAddressOfSymbol(const char* symbolName) { + // First check symbols added via AddSymbol(). + std::map::iterator I = g_symbols.find(symbolName); + if (I != g_symbols.end()) + return I->second; + + // Now search the libraries. for (std::vector::iterator I = OpenedHandles.begin(), E = OpenedHandles.end(); I != E; ++I) { FARPROC ptr = GetProcAddress((HMODULE)*I, symbolName);