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//===-- DynamicLibrary.cpp - Runtime link/load libraries --------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Reid Spencer and is distributed under the
// University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This header file implements the operating system DynamicLibrary concept.
//
//===----------------------------------------------------------------------===//
#include "llvm/System/DynamicLibrary.h"
#include "llvm/Config/config.h"
#include <map>
// Collection of symbol name/value pairs to be searched prior to any libraries.
static std::map<std::string, void *> 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
// the LGPL. This is because the exception applies only when libtool is
// used, and obviously libtool is not used with Visual Studio. An entirely
// separate implementation is provided in win32/DynamicLibrary.cpp.
#ifdef LLVM_ON_WIN32
#include "Win32/DynamicLibrary.inc"
#else
#include "ltdl.h"
#include <cassert>
using namespace llvm;
using namespace llvm::sys;
//===----------------------------------------------------------------------===//
//=== WARNING: Implementation here must contain only TRULY operating system
//=== independent code.
//===----------------------------------------------------------------------===//
static inline void check_ltdl_initialization() {
static bool did_initialize_ltdl = false;
if (!did_initialize_ltdl) {
int Err = lt_dlinit();
Err = Err; // Silence warning.
assert(0 == Err && "Can't init the ltdl library");
did_initialize_ltdl = true;
}
}
static std::vector<lt_dlhandle> OpenedHandles;
DynamicLibrary::DynamicLibrary() : handle(0) {
check_ltdl_initialization();
lt_dlhandle a_handle = lt_dlopen(0);
assert(a_handle == 0 || "Can't open program as dynamic library");
handle = a_handle;
OpenedHandles.push_back(a_handle);
}
/*
DynamicLibrary::DynamicLibrary(const char*filename) : handle(0) {
check_ltdl_initialization();
lt_dlhandle a_handle = lt_dlopen(filename);
if (a_handle == 0)
a_handle = lt_dlopenext(filename);
if (a_handle == 0)
throw std::string("Can't open :") + filename + ": " + lt_dlerror();
handle = a_handle;
OpenedHandles.push_back(a_handle);
}
*/
DynamicLibrary::~DynamicLibrary() {
lt_dlhandle a_handle = (lt_dlhandle) handle;
if (a_handle) {
lt_dlclose(a_handle);
for (std::vector<lt_dlhandle>::iterator I = OpenedHandles.begin(),
E = OpenedHandles.end(); I != E; ++I) {
if (*I == a_handle) {
// Note: don't use the swap/pop_back trick here. Order is important.
OpenedHandles.erase(I);
return;
}
}
}
}
bool DynamicLibrary::LoadLibraryPermanently(const char *Filename,
std::string *ErrMsg) {
check_ltdl_initialization();
lt_dlhandle a_handle = lt_dlopen(Filename);
if (a_handle == 0)
a_handle = lt_dlopenext(Filename);
if (a_handle == 0) {
if (ErrMsg)
*ErrMsg = std::string("Can't open :") +
(Filename ? Filename : "<current process>") + ": " + lt_dlerror();
return true;
}
lt_dlmakeresident(a_handle);
OpenedHandles.push_back(a_handle);
return false;
}
void* DynamicLibrary::SearchForAddressOfSymbol(const char* symbolName) {
check_ltdl_initialization();
// First check symbols added via AddSymbol().
std::map<std::string, void *>::iterator I = g_symbols.find(symbolName);
if (I != g_symbols.end())
return I->second;
// Now search the libraries.
for (std::vector<lt_dlhandle>::iterator I = OpenedHandles.begin(),
E = OpenedHandles.end(); I != E; ++I) {
lt_ptr ptr = lt_dlsym(*I, symbolName);
if (ptr)
return ptr;
}
// If this is darwin, it has some funky issues, try to solve them here. Some
// important symbols are marked 'private external' which doesn't allow
// SearchForAddressOfSymbol to find them. As such, we special case them here,
// there is only a small handful of them.
#ifdef __APPLE__
#define EXPLICIT_SYMBOL(SYM) \
extern void *SYM; if (!strcmp(symbolName, #SYM)) return &SYM
{
EXPLICIT_SYMBOL(__ashldi3);
EXPLICIT_SYMBOL(__ashrdi3);
EXPLICIT_SYMBOL(__cmpdi2);
EXPLICIT_SYMBOL(__divdi3);
EXPLICIT_SYMBOL(__eprintf);
EXPLICIT_SYMBOL(__fixdfdi);
EXPLICIT_SYMBOL(__fixsfdi);
EXPLICIT_SYMBOL(__fixunsdfdi);
EXPLICIT_SYMBOL(__fixunssfdi);
EXPLICIT_SYMBOL(__floatdidf);
EXPLICIT_SYMBOL(__floatdisf);
EXPLICIT_SYMBOL(__lshrdi3);
EXPLICIT_SYMBOL(__moddi3);
EXPLICIT_SYMBOL(__udivdi3);
EXPLICIT_SYMBOL(__umoddi3);
}
#undef EXPLICIT_SYMBOL
#endif
// This macro returns the address of a well-known, explicit symbol
#define EXPLICIT_SYMBOL(SYM) \
if (!strcmp(symbolName, #SYM)) return &SYM
// On linux we have a weird situation. The stderr/out/in symbols are both
// macros and global variables because of standards requirements. So, we
// boldly use the EXPLICIT_SYMBOL macro without checking for a #define first.
#if defined(__linux__)
{
EXPLICIT_SYMBOL(stderr);
EXPLICIT_SYMBOL(stdout);
EXPLICIT_SYMBOL(stdin);
}
#else
// For everything else, we want to check to make sure the symbol isn't defined
// as a macro before using EXPLICIT_SYMBOL.
{
#ifndef stdin
EXPLICIT_SYMBOL(stdin);
#endif
#ifndef stdout
EXPLICIT_SYMBOL(stdout);
#endif
#ifndef stderr
EXPLICIT_SYMBOL(stderr);
#endif
}
#endif
#undef EXPLICIT_SYMBOL
return 0;
}
void *DynamicLibrary::GetAddressOfSymbol(const char *symbolName) {
assert(handle != 0 && "Invalid DynamicLibrary handle");
return lt_dlsym((lt_dlhandle) handle, symbolName);
}
#endif // LLVM_ON_WIN32
DEFINING_FILE_FOR(SystemDynamicLibrary)