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/Compiler.h"
17#include "llvm/Support/DynamicLibrary.h"
18#include "llvm/Support/ErrorHandling.h"
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)(void *)) = 0;
54
55  if (!Searched) {
56    Searched = true;
57    *(void **)&rf =
58        llvm::sys::DynamicLibrary::SearchForAddressOfSymbol("__register_frame");
59  }
60  if (rf)
61    rf(p);
62}
63
64void __deregister_frame(void *p) {
65  static bool Searched = false;
66  static void((*df)(void *)) = 0;
67
68  if (!Searched) {
69    Searched = true;
70    *(void **)&df = llvm::sys::DynamicLibrary::SearchForAddressOfSymbol(
71        "__deregister_frame");
72  }
73  if (df)
74    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::registerEHFramesInProcess(uint8_t *Addr,
98                                                    size_t Size) {
99  // On OS X OS X __register_frame takes a single FDE as an argument.
100  // See http://lists.llvm.org/pipermail/llvm-dev/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::deregisterEHFramesInProcess(uint8_t *Addr,
109                                                      size_t Size) {
110  const char *P = (const char *)Addr;
111  const char *End = P + Size;
112  do  {
113    P = processFDE(P, true);
114  } while(P != End);
115}
116
117#else
118
119void RTDyldMemoryManager::registerEHFramesInProcess(uint8_t *Addr,
120                                                    size_t Size) {
121  // On Linux __register_frame takes a single argument:
122  // a pointer to the start of the .eh_frame section.
123
124  // How can it find the end? Because crtendS.o is linked
125  // in and it has an .eh_frame section with four zero chars.
126  __register_frame(Addr);
127}
128
129void RTDyldMemoryManager::deregisterEHFramesInProcess(uint8_t *Addr,
130                                                      size_t Size) {
131  __deregister_frame(Addr);
132}
133
134#endif
135
136static int jit_noop() {
137  return 0;
138}
139
140// ARM math functions are statically linked on Android from libgcc.a, but not
141// available at runtime for dynamic linking. On Linux these are usually placed
142// in libgcc_s.so so can be found by normal dynamic lookup.
143#if defined(__BIONIC__) && defined(__arm__)
144// List of functions which are statically linked on Android and can be generated
145// by LLVM. This is done as a nested macro which is used once to declare the
146// imported functions with ARM_MATH_DECL and once to compare them to the
147// user-requested symbol in getSymbolAddress with ARM_MATH_CHECK. The test
148// assumes that all functions start with __aeabi_ and getSymbolAddress must be
149// modified if that changes.
150#define ARM_MATH_IMPORTS(PP) \
151  PP(__aeabi_d2f) \
152  PP(__aeabi_d2iz) \
153  PP(__aeabi_d2lz) \
154  PP(__aeabi_d2uiz) \
155  PP(__aeabi_d2ulz) \
156  PP(__aeabi_dadd) \
157  PP(__aeabi_dcmpeq) \
158  PP(__aeabi_dcmpge) \
159  PP(__aeabi_dcmpgt) \
160  PP(__aeabi_dcmple) \
161  PP(__aeabi_dcmplt) \
162  PP(__aeabi_dcmpun) \
163  PP(__aeabi_ddiv) \
164  PP(__aeabi_dmul) \
165  PP(__aeabi_dsub) \
166  PP(__aeabi_f2d) \
167  PP(__aeabi_f2iz) \
168  PP(__aeabi_f2lz) \
169  PP(__aeabi_f2uiz) \
170  PP(__aeabi_f2ulz) \
171  PP(__aeabi_fadd) \
172  PP(__aeabi_fcmpeq) \
173  PP(__aeabi_fcmpge) \
174  PP(__aeabi_fcmpgt) \
175  PP(__aeabi_fcmple) \
176  PP(__aeabi_fcmplt) \
177  PP(__aeabi_fcmpun) \
178  PP(__aeabi_fdiv) \
179  PP(__aeabi_fmul) \
180  PP(__aeabi_fsub) \
181  PP(__aeabi_i2d) \
182  PP(__aeabi_i2f) \
183  PP(__aeabi_idiv) \
184  PP(__aeabi_idivmod) \
185  PP(__aeabi_l2d) \
186  PP(__aeabi_l2f) \
187  PP(__aeabi_lasr) \
188  PP(__aeabi_ldivmod) \
189  PP(__aeabi_llsl) \
190  PP(__aeabi_llsr) \
191  PP(__aeabi_lmul) \
192  PP(__aeabi_ui2d) \
193  PP(__aeabi_ui2f) \
194  PP(__aeabi_uidiv) \
195  PP(__aeabi_uidivmod) \
196  PP(__aeabi_ul2d) \
197  PP(__aeabi_ul2f) \
198  PP(__aeabi_uldivmod)
199
200// Declare statically linked math functions on ARM. The function declarations
201// here do not have the correct prototypes for each function in
202// ARM_MATH_IMPORTS, but it doesn't matter because only the symbol addresses are
203// needed. In particular the __aeabi_*divmod functions do not have calling
204// conventions which match any C prototype.
205#define ARM_MATH_DECL(name) extern "C" void name();
206ARM_MATH_IMPORTS(ARM_MATH_DECL)
207#undef ARM_MATH_DECL
208#endif
209
210#if defined(__linux__) && defined(__GLIBC__) && \
211      (defined(__i386__) || defined(__x86_64__))
212extern "C" LLVM_ATTRIBUTE_WEAK void __morestack();
213#endif
214
215uint64_t
216RTDyldMemoryManager::getSymbolAddressInProcess(const std::string &Name) {
217  // This implementation assumes that the host program is the target.
218  // Clients generating code for a remote target should implement their own
219  // memory manager.
220#if defined(__linux__) && defined(__GLIBC__)
221  //===--------------------------------------------------------------------===//
222  // Function stubs that are invoked instead of certain library calls
223  //
224  // Force the following functions to be linked in to anything that uses the
225  // JIT. This is a hack designed to work around the all-too-clever Glibc
226  // strategy of making these functions work differently when inlined vs. when
227  // not inlined, and hiding their real definitions in a separate archive file
228  // that the dynamic linker can't see. For more info, search for
229  // 'libc_nonshared.a' on Google, or read http://llvm.org/PR274.
230  if (Name == "stat") return (uint64_t)&stat;
231  if (Name == "fstat") return (uint64_t)&fstat;
232  if (Name == "lstat") return (uint64_t)&lstat;
233  if (Name == "stat64") return (uint64_t)&stat64;
234  if (Name == "fstat64") return (uint64_t)&fstat64;
235  if (Name == "lstat64") return (uint64_t)&lstat64;
236  if (Name == "atexit") return (uint64_t)&atexit;
237  if (Name == "mknod") return (uint64_t)&mknod;
238
239#if defined(__i386__) || defined(__x86_64__)
240  // __morestack lives in libgcc, a static library.
241  if (&__morestack && Name == "__morestack")
242    return (uint64_t)&__morestack;
243#endif
244#endif // __linux__ && __GLIBC__
245
246  // See ARM_MATH_IMPORTS definition for explanation
247#if defined(__BIONIC__) && defined(__arm__)
248  if (Name.compare(0, 8, "__aeabi_") == 0) {
249    // Check if the user has requested any of the functions listed in
250    // ARM_MATH_IMPORTS, and if so redirect to the statically linked symbol.
251#define ARM_MATH_CHECK(fn) if (Name == #fn) return (uint64_t)&fn;
252    ARM_MATH_IMPORTS(ARM_MATH_CHECK)
253#undef ARM_MATH_CHECK
254  }
255#endif
256
257  // We should not invoke parent's ctors/dtors from generated main()!
258  // On Mingw and Cygwin, the symbol __main is resolved to
259  // callee's(eg. tools/lli) one, to invoke wrong duplicated ctors
260  // (and register wrong callee's dtors with atexit(3)).
261  // We expect ExecutionEngine::runStaticConstructorsDestructors()
262  // is called before ExecutionEngine::runFunctionAsMain() is called.
263  if (Name == "__main") return (uint64_t)&jit_noop;
264
265  const char *NameStr = Name.c_str();
266
267  // DynamicLibrary::SearchForAddresOfSymbol expects an unmangled 'C' symbol
268  // name so ff we're on Darwin, strip the leading '_' off.
269#ifdef __APPLE__
270  if (NameStr[0] == '_')
271    ++NameStr;
272#endif
273
274  return (uint64_t)sys::DynamicLibrary::SearchForAddressOfSymbol(NameStr);
275}
276
277void *RTDyldMemoryManager::getPointerToNamedFunction(const std::string &Name,
278                                                     bool AbortOnFailure) {
279  uint64_t Addr = getSymbolAddress(Name);
280
281  if (!Addr && AbortOnFailure)
282    report_fatal_error("Program used external function '" + Name +
283                       "' which could not be resolved!");
284
285  return (void*)Addr;
286}
287
288} // namespace llvm
289