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Refactor DynamicLibrary so searching for a symbol will have a defined order and

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libraries are properly unloaded when llvm_shutdown is called.

Summary:
This was mostly affecting usage of the JIT, where storing the library handles in
a set made iteration unordered/undefined. This lead to disagreement between the
JIT and native code as to what the address and implementation of particularly on
Windows with stdlib functions:

JIT: putenv_s("TEST", "VALUE") // called msvcrt.dll, putenv_s
JIT: getenv("TEST") -> "VALUE" // called msvcrt.dll, getenv
Native: getenv("TEST") -> NULL // called ucrt.dll, getenv

Also fixed is the issue of DynamicLibrary::getPermanentLibrary(0,0) on Windows
not giving priority to the process' symbols as it did on Unix.

Reviewers: chapuni, v.g.vassilev, lhames

Reviewed By: lhames

Subscribers: danalbert, srhines, mgorny, vsk, llvm-commits

Differential Revision: https://reviews.llvm.org/D30107

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@301153 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Frederich Munch
2017-04-24 02:30:12 +00:00
parent dd358f5cfd
commit 545de00b4b
11 changed files with 590 additions and 294 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/Support/DynamicLibrary.cpp
+129 -134
View File
@@ -20,169 +20,164 @@
#include "llvm/Support/Mutex.h"
#include <cstdio>
#include <cstring>
#include <vector>
using namespace llvm;
using namespace llvm::sys;
// All methods for HandleSet should be used holding SymbolsMutex.
class DynamicLibrary::HandleSet {
typedef std::vector<void *> HandleList;
HandleList Handles;
void *Process;
public:
static void *DLOpen(const char *Filename, std::string *Err);
static void DLClose(void *Handle);
static void *DLSym(void *Handle, const char *Symbol);
HandleSet() : Process(nullptr) {}
~HandleSet();
HandleList::iterator Find(void *Handle) {
return std::find(Handles.begin(), Handles.end(), Handle);
}
bool Contains(void *Handle) {
return Handle == Process || Find(Handle) != Handles.end();
}
bool AddLibrary(void *Handle, bool IsProcess = false, bool CanClose = true) {
#ifdef LLVM_ON_WIN32
assert((Handle == this ? IsProcess : !IsProcess) && "Bad Handle.");
#endif
if (LLVM_LIKELY(!IsProcess)) {
if (Find(Handle) != Handles.end()) {
if (CanClose)
DLClose(Handle);
return false;
}
Handles.push_back(Handle);
} else {
#ifndef LLVM_ON_WIN32
if (Process) {
if (CanClose)
DLClose(Process);
if (Process == Handle)
return false;
}
#endif
Process = Handle;
}
return true;
}
void *Lookup(const char *Symbol) {
// Process handle gets first try.
if (Process) {
if (void *Ptr = DLSym(Process, Symbol))
return Ptr;
#ifndef NDEBUG
for (void *Handle : Handles)
assert(!DLSym(Handle, Symbol) && "Symbol exists in non process handle");
#endif
} else {
// Iterate in reverse, so newer libraries/symbols override older.
for (auto &&I = Handles.rbegin(), E = Handles.rend(); I != E; ++I) {
if (void *Ptr = DLSym(*I, Symbol))
return Ptr;
}
}
return nullptr;
}
};
namespace {
// 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;
static llvm::ManagedStatic<llvm::StringMap<void *>> ExplicitSymbols;
// Collection of known library handles.
static llvm::ManagedStatic<DynamicLibrary::HandleSet> OpenedHandles;
// Lock for ExplicitSymbols and OpenedHandles.
static llvm::ManagedStatic<llvm::sys::SmartMutex<true>> SymbolsMutex;
}
char llvm::sys::DynamicLibrary::Invalid = 0;
#ifdef LLVM_ON_WIN32
#include "Windows/DynamicLibrary.inc"
#else
#if defined(HAVE_DLFCN_H) && defined(HAVE_DLOPEN)
#include <dlfcn.h>
using namespace llvm;
using namespace llvm::sys;
//===----------------------------------------------------------------------===//
//=== WARNING: Implementation here must contain only TRULY operating system
//=== independent code.
//===----------------------------------------------------------------------===//
static llvm::ManagedStatic<DenseSet<void *> > OpenedHandles;
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 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);
}
DynamicLibrary DynamicLibrary::addPermanentLibrary(void *handle,
std::string *errMsg) {
SmartScopedLock<true> lock(*SymbolsMutex);
// If we've already loaded this library, tell the caller.
if (!OpenedHandles->insert(handle).second) {
if (errMsg) *errMsg = "Library already loaded";
return DynamicLibrary();
}
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;
}
#include "Unix/DynamicLibrary.inc"
#endif
char DynamicLibrary::Invalid;
namespace llvm {
void *SearchForAddressOfSpecialSymbol(const char* symbolName);
void *SearchForAddressOfSpecialSymbol(const char *SymbolName) {
return DoSearch(SymbolName); // DynamicLibrary.inc
}
}
void* DynamicLibrary::SearchForAddressOfSymbol(const char *symbolName) {
void DynamicLibrary::AddSymbol(StringRef SymbolName, void *SymbolValue) {
SmartScopedLock<true> Lock(*SymbolsMutex);
(*ExplicitSymbols)[SymbolName] = SymbolValue;
}
// First check symbols added via AddSymbol().
if (ExplicitSymbols.isConstructed()) {
StringMap<void *>::iterator i = ExplicitSymbols->find(symbolName);
DynamicLibrary DynamicLibrary::getPermanentLibrary(const char *FileName,
std::string *Err) {
SmartScopedLock<true> Lock(*SymbolsMutex);
void *Handle = HandleSet::DLOpen(FileName, Err);
if (Handle != &Invalid)
OpenedHandles->AddLibrary(Handle, /*IsProcess*/ FileName == nullptr);
if (i != ExplicitSymbols->end())
return i->second;
}
return DynamicLibrary(Handle);
}
#if defined(HAVE_DLFCN_H) && defined(HAVE_DLOPEN)
// Now search the libraries.
if (OpenedHandles.isConstructed()) {
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;
}
DynamicLibrary DynamicLibrary::addPermanentLibrary(void *Handle,
std::string *Err) {
SmartScopedLock<true> Lock(*SymbolsMutex);
// If we've already loaded this library, tell the caller.
if (!OpenedHandles->AddLibrary(Handle, /*IsProcess*/false, /*CanClose*/false))
*Err = "Library already loaded";
return DynamicLibrary(Handle);
}
void *DynamicLibrary::getAddressOfSymbol(const char *SymbolName) {
if (!isValid())
return nullptr;
return HandleSet::DLSym(Data, 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;
}
// Now search the libraries.
if (OpenedHandles.isConstructed()) {
if (void *Ptr = OpenedHandles->Lookup(SymbolName))
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;
return llvm::SearchForAddressOfSpecialSymbol(SymbolName);
}
#endif // LLVM_ON_WIN32
//===----------------------------------------------------------------------===//
// C API.
//===----------------------------------------------------------------------===//
LLVMBool LLVMLoadLibraryPermanently(const char* Filename) {
LLVMBool LLVMLoadLibraryPermanently(const char *Filename) {
return llvm::sys::DynamicLibrary::LoadLibraryPermanently(Filename);
}