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llvm-mirror/lib/System/DynamicLibrary.cpp
Jeffrey Yasskin 46115632ba Make clang bootstrap happier on OSX 10.5 by reducing the number of headers
included when using global symbols to ask the linker for the addresses of
various functions.  One of the symbols was actually getting declared by a
header included in DynamicLibrary.cpp, which conflicted with the "extern void*"
declaration in SearchForAddressOfSpecialSymbol().

llvm-svn: 98243
2010-03-11 06:14:32 +00:00

136 lines
3.7 KiB
C++

//===-- 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.
//
// FIXME: This file leaks the ExplicitSymbols and OpenedHandles vector, and is
// not thread safe!
//
//===----------------------------------------------------------------------===//
#include "llvm/System/DynamicLibrary.h"
#include "llvm/Config/config.h"
#include <cstdio>
#include <cstring>
#include <map>
#include <vector>
// Collection of symbol name/value pairs to be searched prior to any libraries.
static std::map<std::string, void*> *ExplicitSymbols = 0;
static struct ExplicitSymbolsDeleter {
~ExplicitSymbolsDeleter() {
if (ExplicitSymbols)
delete ExplicitSymbols;
}
} Dummy;
void llvm::sys::DynamicLibrary::AddSymbol(const char* symbolName,
void *symbolValue) {
if (ExplicitSymbols == 0)
ExplicitSymbols = new std::map<std::string, void*>();
(*ExplicitSymbols)[symbolName] = symbolValue;
}
#ifdef LLVM_ON_WIN32
#include "Win32/DynamicLibrary.inc"
#else
#include <dlfcn.h>
using namespace llvm;
using namespace llvm::sys;
//===----------------------------------------------------------------------===//
//=== WARNING: Implementation here must contain only TRULY operating system
//=== independent code.
//===----------------------------------------------------------------------===//
static std::vector<void *> *OpenedHandles = 0;
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;
}
if (OpenedHandles == 0)
OpenedHandles = new std::vector<void *>();
OpenedHandles->push_back(H);
return false;
}
namespace llvm {
void *SearchForAddressOfSpecialSymbol(const char* symbolName);
}
void* DynamicLibrary::SearchForAddressOfSymbol(const char* symbolName) {
// First check symbols added via AddSymbol().
if (ExplicitSymbols) {
std::map<std::string, void *>::iterator I =
ExplicitSymbols->find(symbolName);
std::map<std::string, void *>::iterator E = ExplicitSymbols->end();
if (I != E)
return I->second;
}
// Now search the libraries.
if (OpenedHandles) {
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;
}
}
}
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__)
{
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