llvm-6502/lib/System/DynamicLibrary.cpp
Douglas Gregor 37b7baec0d Alternative fix to make sure that the extern declarations used by
DynamicLibrary::SearchForAddressOfSymbol refer to declarations in the
global namespace.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92023 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-23 19:12:50 +00:00

172 lines
4.7 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;
}
static void *SearchForAddressOfSpecialSymbol(const char* symbolName) {
#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
return 0;
}
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 = 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