DynamicLibrary.inc revision 360784 
1//===- Win32/DynamicLibrary.cpp - Win32 DL Implementation -------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file provides the Win32 specific implementation of DynamicLibrary.
10//
11//===----------------------------------------------------------------------===//
12
13#include "llvm/Support/Windows/WindowsSupport.h"
14#include "llvm/Support/ConvertUTF.h"
15#include "llvm/Support/raw_ostream.h"
16
17#include <psapi.h>
18
19//===----------------------------------------------------------------------===//
20//=== WARNING: Implementation here must contain only Win32 specific code
21//===          and must not be UNIX code.
22//===----------------------------------------------------------------------===//
23
24
25DynamicLibrary::HandleSet::~HandleSet() {
26  for (void *Handle : llvm::reverse(Handles))
27    FreeLibrary(HMODULE(Handle));
28
29  // 'Process' should not be released on Windows.
30  assert((!Process || Process==this) && "Bad Handle");
31  // llvm_shutdown called, Return to default
32  DynamicLibrary::SearchOrder = DynamicLibrary::SO_Linker;
33}
34
35void *DynamicLibrary::HandleSet::DLOpen(const char *File, std::string *Err) {
36  // Create the instance and return it to be the *Process* handle
37  // simillar to dlopen(NULL, RTLD_LAZY|RTLD_GLOBAL)
38  if (!File)
39    return &(*OpenedHandles);
40
41  SmallVector<wchar_t, MAX_PATH> FileUnicode;
42  if (std::error_code ec = windows::UTF8ToUTF16(File, FileUnicode)) {
43    SetLastError(ec.value());
44    MakeErrMsg(Err, std::string(File) + ": Can't convert to UTF-16");
45    return &DynamicLibrary::Invalid;
46  }
47
48  HMODULE Handle = LoadLibraryW(FileUnicode.data());
49  if (Handle == NULL) {
50    MakeErrMsg(Err, std::string(File) + ": Can't open");
51    return &DynamicLibrary::Invalid;
52  }
53
54  return reinterpret_cast<void*>(Handle);
55}
56
57static DynamicLibrary::HandleSet *IsOpenedHandlesInstance(void *Handle) {
58  if (!OpenedHandles.isConstructed())
59    return nullptr;
60  DynamicLibrary::HandleSet &Inst = *OpenedHandles;
61  return Handle == &Inst ? &Inst : nullptr;
62}
63
64void DynamicLibrary::HandleSet::DLClose(void *Handle) {
65  if (HandleSet* HS = IsOpenedHandlesInstance(Handle))
66    HS->Process = nullptr; // Just drop the *Process* handle.
67  else
68    FreeLibrary((HMODULE)Handle);
69}
70
71static bool GetProcessModules(HANDLE H, DWORD &Bytes, HMODULE *Data = nullptr) {
72  // EnumProcessModules will fail on Windows 64 while some versions of
73  // MingW-32 don't have EnumProcessModulesEx.
74  if (
75#ifdef _WIN64
76      !EnumProcessModulesEx(H, Data, Bytes, &Bytes, LIST_MODULES_64BIT)
77#else
78      !EnumProcessModules(H, Data, Bytes, &Bytes)
79#endif
80     ) {
81    std::string Err;
82    if (MakeErrMsg(&Err, "EnumProcessModules failure"))
83      llvm::errs() << Err << "\n";
84    return false;
85  }
86  return true;
87}
88
89void *DynamicLibrary::HandleSet::DLSym(void *Handle, const char *Symbol) {
90  HandleSet* HS = IsOpenedHandlesInstance(Handle);
91  if (!HS)
92    return (void *)uintptr_t(GetProcAddress((HMODULE)Handle, Symbol));
93
94  // Could have done a dlclose on the *Process* handle
95  if (!HS->Process)
96    return nullptr;
97
98  // Trials indicate EnumProcessModulesEx is consistantly faster than using
99  // EnumerateLoadedModules64 or CreateToolhelp32Snapshot.
100  //
101  // | Handles | DbgHelp.dll | CreateSnapshot | EnumProcessModulesEx
102  // |=========|=============|========================================
103  // | 37      | 0.0000585 * | 0.0003031      | 0.0000152
104  // | 1020    | 0.0026310 * | 0.0121598      | 0.0002683
105  // | 2084    | 0.0149418 * | 0.0369936      | 0.0005610
106  //
107  // * Not including the load time of Dbghelp.dll (~.005 sec)
108  //
109  // There's still a case to somehow cache the result of EnumProcessModulesEx
110  // across invocations, but the complication of doing that properly...
111  // Possibly using LdrRegisterDllNotification to invalidate the cache?
112
113  DWORD Bytes = 0;
114  HMODULE Self = HMODULE(GetCurrentProcess());
115  if (!GetProcessModules(Self, Bytes))
116    return nullptr;
117
118  // Get the most recent list in case any modules added/removed between calls
119  // to EnumProcessModulesEx that gets the amount of, then copies the HMODULES.
120  // MSDN is pretty clear that if the module list changes during the call to
121  // EnumProcessModulesEx the results should not be used.
122  std::vector<HMODULE> Handles;
123  do {
124    assert(Bytes && ((Bytes % sizeof(HMODULE)) == 0) &&
125           "Should have at least one module and be aligned");
126    Handles.resize(Bytes / sizeof(HMODULE));
127    if (!GetProcessModules(Self, Bytes, Handles.data()))
128      return nullptr;
129  } while (Bytes != (Handles.size() * sizeof(HMODULE)));
130
131  // Try EXE first, mirroring what dlsym(dlopen(NULL)) does.
132  if (FARPROC Ptr = GetProcAddress(HMODULE(Handles.front()), Symbol))
133    return (void *) uintptr_t(Ptr);
134
135  if (Handles.size() > 1) {
136    // This is different behaviour than what Posix dlsym(dlopen(NULL)) does.
137    // Doing that here is causing real problems for the JIT where msvc.dll
138    // and ucrt.dll can define the same symbols. The runtime linker will choose
139    // symbols from ucrt.dll first, but iterating NOT in reverse here would
140    // mean that the msvc.dll versions would be returned.
141
142    for (auto I = Handles.rbegin(), E = Handles.rend()-1; I != E; ++I) {
143      if (FARPROC Ptr = GetProcAddress(HMODULE(*I), Symbol))
144        return (void *) uintptr_t(Ptr);
145    }
146  }
147  return nullptr;
148}
149
150
151// Stack probing routines are in the support library (e.g. libgcc), but we don't
152// have dynamic linking on windows. Provide a hook.
153#define EXPLICIT_SYMBOL(SYM)                    \
154  extern "C" { extern void *SYM; }
155#define EXPLICIT_SYMBOL2(SYMFROM, SYMTO) EXPLICIT_SYMBOL(SYMTO)
156
157#ifdef _M_IX86
158// Win32 on x86 implements certain single-precision math functions as macros.
159// These functions are not exported by the DLL, but will still be needed
160// for symbol-resolution by the JIT loader. Therefore, this Support libray
161// provides helper functions with the same implementation.
162
163#define INLINE_DEF_SYMBOL1(TYP, SYM)                                           \
164  extern "C" TYP inline_##SYM(TYP _X) { return SYM(_X); }
165#define INLINE_DEF_SYMBOL2(TYP, SYM)                                           \
166  extern "C" TYP inline_##SYM(TYP _X, TYP _Y) { return SYM(_X, _Y); }
167#endif
168
169#include "explicit_symbols.inc"
170
171#undef EXPLICIT_SYMBOL
172#undef EXPLICIT_SYMBOL2
173#undef INLINE_DEF_SYMBOL1
174#undef INLINE_DEF_SYMBOL2
175
176static void *DoSearch(const char *SymbolName) {
177
178#define EXPLICIT_SYMBOL(SYM)                                                   \
179  if (!strcmp(SymbolName, #SYM))                                               \
180    return (void *)&SYM;
181#define EXPLICIT_SYMBOL2(SYMFROM, SYMTO)                                       \
182  if (!strcmp(SymbolName, #SYMFROM))                                           \
183    return (void *)&SYMTO;
184
185#ifdef _M_IX86
186#define INLINE_DEF_SYMBOL1(TYP, SYM)                                           \
187  if (!strcmp(SymbolName, #SYM))                                               \
188    return (void *)&inline_##SYM;
189#define INLINE_DEF_SYMBOL2(TYP, SYM) INLINE_DEF_SYMBOL1(TYP, SYM)
190#endif
191
192  {
193#include "explicit_symbols.inc"
194  }
195
196#undef EXPLICIT_SYMBOL
197#undef EXPLICIT_SYMBOL2
198#undef INLINE_DEF_SYMBOL1
199#undef INLINE_DEF_SYMBOL2
200
201  return nullptr;
202}
203