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