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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 file implements the operating system DynamicLibrary concept.
//
// FIXME: This file leaks ExplicitSymbols and OpenedHandles!
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/DynamicLibrary.h"
#include "llvm-c/Support.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Config/config.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/Mutex.h"
#include <cstdio>
#include <cstring>
// Collection of symbol name/value pairs to be searched prior to any libraries.
static llvm::ManagedStatic<llvm::StringMap<void *> > ExplicitSymbols;
static llvm::ManagedStatic<llvm::sys::SmartMutex<true> > SymbolsMutex;
void llvm::sys::DynamicLibrary::AddSymbol(StringRef symbolName,
void *symbolValue) {
SmartScopedLock<true> lock(*SymbolsMutex);
(*ExplicitSymbols)[symbolName] = symbolValue;
}
char llvm::sys::DynamicLibrary::Invalid = 0;
#ifdef LLVM_ON_WIN32
#include "Windows/DynamicLibrary.inc"
#else
#if HAVE_DLFCN_H
#include <dlfcn.h>
using namespace llvm;
using namespace llvm::sys;
//===----------------------------------------------------------------------===//
//=== WARNING: Implementation here must contain only TRULY operating system
//=== independent code.
//===----------------------------------------------------------------------===//
static DenseSet<void *> *OpenedHandles = nullptr;
DynamicLibrary DynamicLibrary::getPermanentLibrary(const char *filename,
std::string *errMsg) {
SmartScopedLock<true> lock(*SymbolsMutex);
void *handle = dlopen(filename, RTLD_LAZY|RTLD_GLOBAL);
if (!handle) {
if (errMsg) *errMsg = dlerror();
return DynamicLibrary();
}
#ifdef __CYGWIN__
// Cygwin searches symbols only in the main
// with the handle of dlopen(NULL, RTLD_GLOBAL).
if (!filename)
handle = RTLD_DEFAULT;
#endif
if (!OpenedHandles)
OpenedHandles = new DenseSet<void *>();
// If we've already loaded this library, dlclose() the handle in order to
// keep the internal refcount at +1.
if (!OpenedHandles->insert(handle).second)
dlclose(handle);
return DynamicLibrary(handle);
}
void *DynamicLibrary::getAddressOfSymbol(const char *symbolName) {
if (!isValid())
return nullptr;
return dlsym(Data, symbolName);
}
#else
using namespace llvm;
using namespace llvm::sys;
DynamicLibrary DynamicLibrary::getPermanentLibrary(const char *filename,
std::string *errMsg) {
if (errMsg) *errMsg = "dlopen() not supported on this platform";
return DynamicLibrary();
}
void *DynamicLibrary::getAddressOfSymbol(const char *symbolName) {
return NULL;
}
#endif
namespace llvm {
void *SearchForAddressOfSpecialSymbol(const char* symbolName);
}
void* DynamicLibrary::SearchForAddressOfSymbol(const char *symbolName) {
SmartScopedLock<true> Lock(*SymbolsMutex);
// First check symbols added via AddSymbol().
if (ExplicitSymbols.isConstructed()) {
StringMap<void *>::iterator i = ExplicitSymbols->find(symbolName);
if (i != ExplicitSymbols->end())
return i->second;
}
#if HAVE_DLFCN_H
// Now search the libraries.
if (OpenedHandles) {
for (DenseSet<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;
}
}
}
#endif
if (void *Result = llvm::SearchForAddressOfSpecialSymbol(symbolName))
return Result;
// 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__) and !defined(__ANDROID__)
{
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 nullptr;
}
#endif // LLVM_ON_WIN32
//===----------------------------------------------------------------------===//
// C API.
//===----------------------------------------------------------------------===//
LLVMBool LLVMLoadLibraryPermanently(const char* Filename) {
return llvm::sys::DynamicLibrary::LoadLibraryPermanently(Filename);
}
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