RTDyldMemoryManager.cpp revision dbb832b83351cec97b025b61c26536ef50c3181c 
1//===-- RTDyldMemoryManager.cpp - Memory manager for MC-JIT -----*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// Implementation of the runtime dynamic memory manager base class.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/Config/config.h"
15#include "llvm/ExecutionEngine/RTDyldMemoryManager.h"
16#include "llvm/Support/DynamicLibrary.h"
17#include "llvm/Support/ErrorHandling.h"
18
19#include <cstdlib>
20
21#ifdef __linux__
22  // These includes used by RTDyldMemoryManager::getPointerToNamedFunction()
23  // for Glibc trickery. See comments in this function for more information.
24  #ifdef HAVE_SYS_STAT_H
25    #include <sys/stat.h>
26  #endif
27  #include <fcntl.h>
28  #include <unistd.h>
29#endif
30
31namespace llvm {
32
33RTDyldMemoryManager::~RTDyldMemoryManager() {}
34
35// Determine whether we can register EH tables.
36#if (defined(__GNUC__) && !defined(__ARM_EABI__) && !defined(__ia64__) && \
37     !defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__))
38#define HAVE_EHTABLE_SUPPORT 1
39#else
40#define HAVE_EHTABLE_SUPPORT 0
41#endif
42
43#if HAVE_EHTABLE_SUPPORT
44extern "C" void __register_frame(void*);
45extern "C" void __deregister_frame(void*);
46#else
47// The building compiler does not have __(de)register_frame but
48// it may be found at runtime in a dynamically-loaded library.
49// For example, this happens when building LLVM with Visual C++
50// but using the MingW runtime.
51void __register_frame(void *p) {
52  static bool Searched = false;
53  static void *rf = 0;
54
55  if (!Searched) {
56    Searched = true;
57    rf = llvm::sys::DynamicLibrary::SearchForAddressOfSymbol(
58                                                      "__register_frame");
59  }
60  if (rf)
61    ((void (*)(void *))rf)(p);
62}
63
64void __deregister_frame(void *p) {
65  static bool Searched = false;
66  static void *df = 0;
67
68  if (!Searched) {
69    Searched = true;
70    df = llvm::sys::DynamicLibrary::SearchForAddressOfSymbol(
71                                                      "__deregister_frame");
72  }
73  if (df)
74    ((void (*)(void *))df)(p);
75}
76#endif
77
78#ifdef __APPLE__
79
80static const char *processFDE(const char *Entry, bool isDeregister) {
81  const char *P = Entry;
82  uint32_t Length = *((const uint32_t *)P);
83  P += 4;
84  uint32_t Offset = *((const uint32_t *)P);
85  if (Offset != 0) {
86    if (isDeregister)
87      __deregister_frame(const_cast<char *>(Entry));
88    else
89      __register_frame(const_cast<char *>(Entry));
90  }
91  return P + Length;
92}
93
94// This implementation handles frame registration for local targets.
95// Memory managers for remote targets should re-implement this function
96// and use the LoadAddr parameter.
97void RTDyldMemoryManager::registerEHFrames(uint8_t *Addr,
98                                           uint64_t LoadAddr,
99                                           size_t Size) {
100  // On OS X OS X __register_frame takes a single FDE as an argument.
101  // See http://lists.cs.uiuc.edu/pipermail/llvmdev/2013-April/061768.html
102  const char *P = (const char *)Addr;
103  const char *End = P + Size;
104  do  {
105    P = processFDE(P, false);
106  } while(P != End);
107}
108
109void RTDyldMemoryManager::deregisterEHFrames(uint8_t *Addr,
110                                           uint64_t LoadAddr,
111                                           size_t Size) {
112  const char *P = (const char *)Addr;
113  const char *End = P + Size;
114  do  {
115    P = processFDE(P, true);
116  } while(P != End);
117}
118
119#else
120
121void RTDyldMemoryManager::registerEHFrames(uint8_t *Addr,
122                                           uint64_t LoadAddr,
123                                           size_t Size) {
124  // On Linux __register_frame takes a single argument:
125  // a pointer to the start of the .eh_frame section.
126
127  // How can it find the end? Because crtendS.o is linked
128  // in and it has an .eh_frame section with four zero chars.
129  __register_frame(Addr);
130}
131
132void RTDyldMemoryManager::deregisterEHFrames(uint8_t *Addr,
133                                           uint64_t LoadAddr,
134                                           size_t Size) {
135  __deregister_frame(Addr);
136}
137
138#endif
139
140static int jit_noop() {
141  return 0;
142}
143
144// ARM math functions are statically linked on Android from libgcc.a, but not
145// available at runtime for dynamic linking. On Linux these are usually placed
146// in libgcc_s.so so can be found by normal dynamic lookup.
147#if defined(__BIONIC__) && defined(__arm__)
148// List of functions which are statically linked on Android and can be generated
149// by LLVM. This is done as a nested macro which is used once to declare the
150// imported functions with ARM_MATH_DECL and once to compare them to the
151// user-requested symbol in getSymbolAddress with ARM_MATH_CHECK. The test
152// assumes that all functions start with __aeabi_ and getSymbolAddress must be
153// modified if that changes.
154#define ARM_MATH_IMPORTS(PP) \
155  PP(__aeabi_d2f) \
156  PP(__aeabi_d2iz) \
157  PP(__aeabi_d2lz) \
158  PP(__aeabi_d2uiz) \
159  PP(__aeabi_d2ulz) \
160  PP(__aeabi_dadd) \
161  PP(__aeabi_dcmpeq) \
162  PP(__aeabi_dcmpge) \
163  PP(__aeabi_dcmpgt) \
164  PP(__aeabi_dcmple) \
165  PP(__aeabi_dcmplt) \
166  PP(__aeabi_dcmpun) \
167  PP(__aeabi_ddiv) \
168  PP(__aeabi_dmul) \
169  PP(__aeabi_dsub) \
170  PP(__aeabi_f2d) \
171  PP(__aeabi_f2iz) \
172  PP(__aeabi_f2lz) \
173  PP(__aeabi_f2uiz) \
174  PP(__aeabi_f2ulz) \
175  PP(__aeabi_fadd) \
176  PP(__aeabi_fcmpeq) \
177  PP(__aeabi_fcmpge) \
178  PP(__aeabi_fcmpgt) \
179  PP(__aeabi_fcmple) \
180  PP(__aeabi_fcmplt) \
181  PP(__aeabi_fcmpun) \
182  PP(__aeabi_fdiv) \
183  PP(__aeabi_fmul) \
184  PP(__aeabi_fsub) \
185  PP(__aeabi_i2d) \
186  PP(__aeabi_i2f) \
187  PP(__aeabi_idiv) \
188  PP(__aeabi_idivmod) \
189  PP(__aeabi_l2d) \
190  PP(__aeabi_l2f) \
191  PP(__aeabi_lasr) \
192  PP(__aeabi_ldivmod) \
193  PP(__aeabi_llsl) \
194  PP(__aeabi_llsr) \
195  PP(__aeabi_lmul) \
196  PP(__aeabi_ui2d) \
197  PP(__aeabi_ui2f) \
198  PP(__aeabi_uidiv) \
199  PP(__aeabi_uidivmod) \
200  PP(__aeabi_ul2d) \
201  PP(__aeabi_ul2f) \
202  PP(__aeabi_uldivmod)
203
204// Declare statically linked math functions on ARM. The function declarations
205// here do not have the correct prototypes for each function in
206// ARM_MATH_IMPORTS, but it doesn't matter because only the symbol addresses are
207// needed. In particular the __aeabi_*divmod functions do not have calling
208// conventions which match any C prototype.
209#define ARM_MATH_DECL(name) extern "C" void name();
210ARM_MATH_IMPORTS(ARM_MATH_DECL)
211#undef ARM_MATH_DECL
212#endif
213
214uint64_t RTDyldMemoryManager::getSymbolAddress(const std::string &Name) {
215  // This implementation assumes that the host program is the target.
216  // Clients generating code for a remote target should implement their own
217  // memory manager.
218#if defined(__linux__) && defined(__GLIBC__)
219  //===--------------------------------------------------------------------===//
220  // Function stubs that are invoked instead of certain library calls
221  //
222  // Force the following functions to be linked in to anything that uses the
223  // JIT. This is a hack designed to work around the all-too-clever Glibc
224  // strategy of making these functions work differently when inlined vs. when
225  // not inlined, and hiding their real definitions in a separate archive file
226  // that the dynamic linker can't see. For more info, search for
227  // 'libc_nonshared.a' on Google, or read http://llvm.org/PR274.
228  if (Name == "stat") return (uint64_t)&stat;
229  if (Name == "fstat") return (uint64_t)&fstat;
230  if (Name == "lstat") return (uint64_t)&lstat;
231  if (Name == "stat64") return (uint64_t)&stat64;
232  if (Name == "fstat64") return (uint64_t)&fstat64;
233  if (Name == "lstat64") return (uint64_t)&lstat64;
234  if (Name == "atexit") return (uint64_t)&atexit;
235  if (Name == "mknod") return (uint64_t)&mknod;
236#endif // __linux__ && __GLIBC__
237
238  // See ARM_MATH_IMPORTS definition for explanation
239#if defined(__BIONIC__) && defined(__arm__)
240  if (Name.compare(0, 8, "__aeabi_") == 0) {
241    // Check if the user has requested any of the functions listed in
242    // ARM_MATH_IMPORTS, and if so redirect to the statically linked symbol.
243#define ARM_MATH_CHECK(fn) if (Name == #fn) return (uint64_t)&fn;
244    ARM_MATH_IMPORTS(ARM_MATH_CHECK)
245#undef ARM_MATH_CHECK
246  }
247#endif
248
249  // We should not invoke parent's ctors/dtors from generated main()!
250  // On Mingw and Cygwin, the symbol __main is resolved to
251  // callee's(eg. tools/lli) one, to invoke wrong duplicated ctors
252  // (and register wrong callee's dtors with atexit(3)).
253  // We expect ExecutionEngine::runStaticConstructorsDestructors()
254  // is called before ExecutionEngine::runFunctionAsMain() is called.
255  if (Name == "__main") return (uint64_t)&jit_noop;
256
257  const char *NameStr = Name.c_str();
258  void *Ptr = sys::DynamicLibrary::SearchForAddressOfSymbol(NameStr);
259  if (Ptr)
260    return (uint64_t)Ptr;
261
262  // If it wasn't found and if it starts with an underscore ('_') character,
263  // try again without the underscore.
264  if (NameStr[0] == '_') {
265    Ptr = sys::DynamicLibrary::SearchForAddressOfSymbol(NameStr+1);
266    if (Ptr)
267      return (uint64_t)Ptr;
268  }
269  return 0;
270}
271
272void *RTDyldMemoryManager::getPointerToNamedFunction(const std::string &Name,
273                                                     bool AbortOnFailure) {
274  uint64_t Addr = getSymbolAddress(Name);
275
276  if (!Addr && AbortOnFailure)
277    report_fatal_error("Program used external function '" + Name +
278                       "' which could not be resolved!");
279  return (void*)Addr;
280}
281
282} // namespace llvm
283