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//===- Win32/DynamicLibrary.cpp - Win32 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 Win32 specific implementation of DynamicLibrary.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/Windows/WindowsSupport.h"
#include "llvm/Support/ConvertUTF.h"
#include "llvm/Support/raw_ostream.h"
#include <psapi.h>
//===----------------------------------------------------------------------===//
//=== WARNING: Implementation here must contain only Win32 specific code
//=== and must not be UNIX code.
//===----------------------------------------------------------------------===//
DynamicLibrary::HandleSet::~HandleSet() {
for (void *Handle : llvm::reverse(Handles))
FreeLibrary(HMODULE(Handle));
// 'Process' should not be released on Windows.
assert((!Process || Process==this) && "Bad Handle");
// llvm_shutdown called, Return to default
DynamicLibrary::SearchOrder = DynamicLibrary::SO_Linker;
}
void *DynamicLibrary::HandleSet::DLOpen(const char *File, std::string *Err) {
// Create the instance and return it to be the *Process* handle
// simillar to dlopen(NULL, RTLD_LAZY|RTLD_GLOBAL)
if (!File)
return &(*OpenedHandles);
SmallVector<wchar_t, MAX_PATH> FileUnicode;
if (std::error_code ec = windows::UTF8ToUTF16(File, FileUnicode)) {
SetLastError(ec.value());
MakeErrMsg(Err, std::string(File) + ": Can't convert to UTF-16");
return &DynamicLibrary::Invalid;
}
HMODULE Handle = LoadLibraryW(FileUnicode.data());
if (Handle == NULL) {
MakeErrMsg(Err, std::string(File) + ": Can't open");
return &DynamicLibrary::Invalid;
}
return reinterpret_cast<void*>(Handle);
}
static DynamicLibrary::HandleSet *IsOpenedHandlesInstance(void *Handle) {
if (!OpenedHandles.isConstructed())
return nullptr;
DynamicLibrary::HandleSet &Inst = *OpenedHandles;
return Handle == &Inst ? &Inst : nullptr;
}
void DynamicLibrary::HandleSet::DLClose(void *Handle) {
if (HandleSet* HS = IsOpenedHandlesInstance(Handle))
HS->Process = nullptr; // Just drop the *Process* handle.
else
FreeLibrary((HMODULE)Handle);
}
static bool GetProcessModules(HANDLE H, DWORD &Bytes, HMODULE *Data = nullptr) {
// EnumProcessModules will fail on Windows 64 while some versions of
// MingW-32 don't have EnumProcessModulesEx.
if (
#ifdef _WIN64
!EnumProcessModulesEx(H, Data, Bytes, &Bytes, LIST_MODULES_64BIT)
#else
!EnumProcessModules(H, Data, Bytes, &Bytes)
#endif
) {
std::string Err;
if (MakeErrMsg(&Err, "EnumProcessModules failure"))
llvm::errs() << Err << "\n";
return false;
}
return true;
}
void *DynamicLibrary::HandleSet::DLSym(void *Handle, const char *Symbol) {
HandleSet* HS = IsOpenedHandlesInstance(Handle);
if (!HS)
return (void *)uintptr_t(GetProcAddress((HMODULE)Handle, Symbol));
// Could have done a dlclose on the *Process* handle
if (!HS->Process)
return nullptr;
// Trials indicate EnumProcessModulesEx is consistantly faster than using
// EnumerateLoadedModules64 or CreateToolhelp32Snapshot.
//
// | Handles | DbgHelp.dll | CreateSnapshot | EnumProcessModulesEx
// |=========|=============|========================================
// | 37 | 0.0000585 * | 0.0003031 | 0.0000152
// | 1020 | 0.0026310 * | 0.0121598 | 0.0002683
// | 2084 | 0.0149418 * | 0.0369936 | 0.0005610
//
// * Not including the load time of Dbghelp.dll (~.005 sec)
//
// There's still a case to somehow cache the result of EnumProcessModulesEx
// across invocations, but the complication of doing that properly...
// Possibly using LdrRegisterDllNotification to invalidate the cache?
DWORD Bytes = 0;
HMODULE Self = HMODULE(GetCurrentProcess());
if (!GetProcessModules(Self, Bytes))
return nullptr;
// Get the most recent list in case any modules added/removed between calls
// to EnumProcessModulesEx that gets the amount of, then copies the HMODULES.
// MSDN is pretty clear that if the module list changes during the call to
// EnumProcessModulesEx the results should not be used.
std::vector<HMODULE> Handles;
do {
assert(Bytes && ((Bytes % sizeof(HMODULE)) == 0) &&
"Should have at least one module and be aligned");
Handles.resize(Bytes / sizeof(HMODULE));
if (!GetProcessModules(Self, Bytes, Handles.data()))
return nullptr;
} while (Bytes != (Handles.size() * sizeof(HMODULE)));
// Try EXE first, mirroring what dlsym(dlopen(NULL)) does.
if (FARPROC Ptr = GetProcAddress(HMODULE(Handles.front()), Symbol))
return (void *) uintptr_t(Ptr);
if (Handles.size() > 1) {
// This is different behaviour than what Posix dlsym(dlopen(NULL)) does.
// Doing that here is causing real problems for the JIT where msvc.dll
// and ucrt.dll can define the same symbols. The runtime linker will choose
// symbols from ucrt.dll first, but iterating NOT in reverse here would
// mean that the msvc.dll versions would be returned.
for (auto I = Handles.rbegin(), E = Handles.rend()-1; I != E; ++I) {
if (FARPROC Ptr = GetProcAddress(HMODULE(*I), Symbol))
return (void *) uintptr_t(Ptr);
}
}
return nullptr;
}
// Stack probing routines are in the support library (e.g. libgcc), but we don't
// have dynamic linking on windows. Provide a hook.
#define EXPLICIT_SYMBOL(SYM) \
extern "C" { extern void *SYM; }
#define EXPLICIT_SYMBOL2(SYMFROM, SYMTO) EXPLICIT_SYMBOL(SYMTO)
#ifdef _M_IX86
// Win32 on x86 implements certain single-precision math functions as macros.
// These functions are not exported by the DLL, but will still be needed
// for symbol-resolution by the JIT loader. Therefore, this Support libray
// provides helper functions with the same implementation.
#define INLINE_DEF_SYMBOL1(TYP, SYM) \
extern "C" TYP inline_##SYM(TYP _X) { return SYM(_X); }
#define INLINE_DEF_SYMBOL2(TYP, SYM) \
extern "C" TYP inline_##SYM(TYP _X, TYP _Y) { return SYM(_X, _Y); }
#endif
#include "explicit_symbols.inc"
#undef EXPLICIT_SYMBOL
#undef EXPLICIT_SYMBOL2
#undef INLINE_DEF_SYMBOL1
#undef INLINE_DEF_SYMBOL2
static void *DoSearch(const char *SymbolName) {
#define EXPLICIT_SYMBOL(SYM) \
if (!strcmp(SymbolName, #SYM)) \
return (void *)&SYM;
#define EXPLICIT_SYMBOL2(SYMFROM, SYMTO) \
if (!strcmp(SymbolName, #SYMFROM)) \
return (void *)&SYMTO;
#ifdef _M_IX86
#define INLINE_DEF_SYMBOL1(TYP, SYM) \
if (!strcmp(SymbolName, #SYM)) \
return (void *)&inline_##SYM;
#define INLINE_DEF_SYMBOL2(TYP, SYM) INLINE_DEF_SYMBOL1(TYP, SYM)
#endif
{
#include "explicit_symbols.inc"
}
#undef EXPLICIT_SYMBOL
#undef EXPLICIT_SYMBOL2
#undef INLINE_DEF_SYMBOL1
#undef INLINE_DEF_SYMBOL2
return nullptr;
}
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