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//===-- DynamicLibrary.cpp - Runtime link/load libraries --------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file 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 <cstring>
#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 <dlfcn.h>
#include <cassert>
using namespace llvm;
using namespace llvm::sys;
//===----------------------------------------------------------------------===//
//=== WARNING: Implementation here must contain only TRULY operating system
//=== independent code.
//===----------------------------------------------------------------------===//
//static std::vector<lt_dlhandle> OpenedHandles;
static std::vector<void *> OpenedHandles;
DynamicLibrary::DynamicLibrary() {}
DynamicLibrary::~DynamicLibrary() {
while(!OpenedHandles.empty()) {
void *H = OpenedHandles.back(); OpenedHandles.pop_back();
dlclose(H);
}
}
bool DynamicLibrary::LoadLibraryPermanently(const char *Filename,
std::string *ErrMsg) {
void *H = dlopen(Filename, RTLD_LAZY|RTLD_GLOBAL);
if (H == 0) {
if (ErrMsg)
*ErrMsg = dlerror();
return true;
}
OpenedHandles.push_back(H);
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<void *>::iterator I = OpenedHandles.begin(),
E = OpenedHandles.end(); I != E; ++I) {
//lt_ptr ptr = lt_dlsym(*I, symbolName);
void *ptr = dlsym(*I, symbolName);
if (ptr)
return ptr;
}
#define EXPLICIT_SYMBOL(SYM) \
extern void *SYM; if (!strcmp(symbolName, #SYM)) return &SYM
// 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__
{
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);
}
#endif
#ifdef __CYGWIN__
{
EXPLICIT_SYMBOL(_alloca);
EXPLICIT_SYMBOL(__main);
}
#endif
#undef EXPLICIT_SYMBOL
// 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;
}
#endif // LLVM_ON_WIN32
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