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//===- Unix/DynamicLibrary.cpp - Unix DL Implementation ---------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file provides the UNIX specific implementation of DynamicLibrary.
//
//===----------------------------------------------------------------------===//
#if defined(HAVE_DLFCN_H) && defined(HAVE_DLOPEN)
#include <dlfcn.h>
DynamicLibrary::HandleSet::~HandleSet() {
// Close the libraries in reverse order.
for (void *Handle : llvm::reverse(Handles))
::dlclose(Handle);
if (Process)
::dlclose(Process);
// llvm_shutdown called, Return to default
DynamicLibrary::SearchOrder = DynamicLibrary::SO_Linker;
}
void *DynamicLibrary::HandleSet::DLOpen(const char *File, std::string *Err) {
void *Handle = ::dlopen(File, RTLD_LAZY | RTLD_GLOBAL);
if (!Handle) {
if (Err)
*Err = ::dlerror();
return &DynamicLibrary::Invalid;
}
#ifdef __CYGWIN__
// Cygwin searches symbols only in the main
// with the handle of dlopen(NULL, RTLD_GLOBAL).
if (!File)
Handle = RTLD_DEFAULT;
#endif
return Handle;
}
void DynamicLibrary::HandleSet::DLClose(void *Handle) { ::dlclose(Handle); }
void *DynamicLibrary::HandleSet::DLSym(void *Handle, const char *Symbol) {
return ::dlsym(Handle, Symbol);
}
#else // !HAVE_DLOPEN
DynamicLibrary::HandleSet::~HandleSet() {}
void *DynamicLibrary::HandleSet::DLOpen(const char *File, std::string *Err) {
if (Err)
*Err = "dlopen() not supported on this platform";
return &Invalid;
}
void DynamicLibrary::HandleSet::DLClose(void *Handle) {}
void *DynamicLibrary::HandleSet::DLSym(void *Handle, const char *Symbol) {
return nullptr;
}
#endif
// Must declare the symbols in the global namespace.
static void *DoSearch(const char *SymbolName) {
#define EXPLICIT_SYMBOL(SYM) \
extern void *SYM; \
if (!strcmp(SymbolName, #SYM)) \
return (void *)&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__
{
// __eprintf is sometimes used for assert() handling on x86.
//
// FIXME: Currently disabled when using Clang, as we don't always have our
// runtime support libraries available.
#ifndef __clang__
#ifdef __i386__
EXPLICIT_SYMBOL(__eprintf);
#endif
#endif
}
#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
// Under glibc 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(__GLIBC__)
{
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;
}
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