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
31 namespace llvm {
32
~RTDyldMemoryManager()33 RTDyldMemoryManager::~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
44 extern "C" void __register_frame(void*);
45 extern "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.
__register_frame(void * p)51 void __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
__deregister_frame(void * p)64 void __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
processFDE(const char * Entry,bool isDeregister)80 static 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.
registerEHFrames(uint8_t * Addr,uint64_t LoadAddr,size_t Size)97 void 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
deregisterEHFrames(uint8_t * Addr,uint64_t LoadAddr,size_t Size)109 void 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
registerEHFrames(uint8_t * Addr,uint64_t LoadAddr,size_t Size)121 void 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
deregisterEHFrames(uint8_t * Addr,uint64_t LoadAddr,size_t Size)132 void RTDyldMemoryManager::deregisterEHFrames(uint8_t *Addr,
133 uint64_t LoadAddr,
134 size_t Size) {
135 __deregister_frame(Addr);
136 }
137
138 #endif
139
jit_noop()140 static 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();
210 ARM_MATH_IMPORTS(ARM_MATH_DECL)
211 #undef ARM_MATH_DECL
212 #endif
213
214 #if defined(__linux__) && defined(__GLIBC__) && \
215 (defined(__i386__) || defined(__x86_64__))
216 extern "C" LLVM_ATTRIBUTE_WEAK void __morestack();
217 #endif
218
219 uint64_t
getSymbolAddressInProcess(const std::string & Name)220 RTDyldMemoryManager::getSymbolAddressInProcess(const std::string &Name) {
221 // This implementation assumes that the host program is the target.
222 // Clients generating code for a remote target should implement their own
223 // memory manager.
224 #if defined(__linux__) && defined(__GLIBC__)
225 //===--------------------------------------------------------------------===//
226 // Function stubs that are invoked instead of certain library calls
227 //
228 // Force the following functions to be linked in to anything that uses the
229 // JIT. This is a hack designed to work around the all-too-clever Glibc
230 // strategy of making these functions work differently when inlined vs. when
231 // not inlined, and hiding their real definitions in a separate archive file
232 // that the dynamic linker can't see. For more info, search for
233 // 'libc_nonshared.a' on Google, or read http://llvm.org/PR274.
234 if (Name == "stat") return (uint64_t)&stat;
235 if (Name == "fstat") return (uint64_t)&fstat;
236 if (Name == "lstat") return (uint64_t)&lstat;
237 if (Name == "stat64") return (uint64_t)&stat64;
238 if (Name == "fstat64") return (uint64_t)&fstat64;
239 if (Name == "lstat64") return (uint64_t)&lstat64;
240 if (Name == "atexit") return (uint64_t)&atexit;
241 if (Name == "mknod") return (uint64_t)&mknod;
242
243 #if defined(__i386__) || defined(__x86_64__)
244 // __morestack lives in libgcc, a static library.
245 if (&__morestack && Name == "__morestack")
246 return (uint64_t)&__morestack;
247 #endif
248 #endif // __linux__ && __GLIBC__
249
250 // See ARM_MATH_IMPORTS definition for explanation
251 #if defined(__BIONIC__) && defined(__arm__)
252 if (Name.compare(0, 8, "__aeabi_") == 0) {
253 // Check if the user has requested any of the functions listed in
254 // ARM_MATH_IMPORTS, and if so redirect to the statically linked symbol.
255 #define ARM_MATH_CHECK(fn) if (Name == #fn) return (uint64_t)&fn;
256 ARM_MATH_IMPORTS(ARM_MATH_CHECK)
257 #undef ARM_MATH_CHECK
258 }
259 #endif
260
261 // We should not invoke parent's ctors/dtors from generated main()!
262 // On Mingw and Cygwin, the symbol __main is resolved to
263 // callee's(eg. tools/lli) one, to invoke wrong duplicated ctors
264 // (and register wrong callee's dtors with atexit(3)).
265 // We expect ExecutionEngine::runStaticConstructorsDestructors()
266 // is called before ExecutionEngine::runFunctionAsMain() is called.
267 if (Name == "__main") return (uint64_t)&jit_noop;
268
269 // Try to demangle Name before looking it up in the process, otherwise symbol
270 // '_<Name>' (if present) will shadow '<Name>', and there will be no way to
271 // refer to the latter.
272
273 const char *NameStr = Name.c_str();
274
275 if (NameStr[0] == '_')
276 if (void *Ptr = sys::DynamicLibrary::SearchForAddressOfSymbol(NameStr + 1))
277 return (uint64_t)Ptr;
278
279 // If we Name did not require demangling, or we failed to find the demangled
280 // name, try again without demangling.
281 return (uint64_t)sys::DynamicLibrary::SearchForAddressOfSymbol(NameStr);
282 }
283
getPointerToNamedFunction(const std::string & Name,bool AbortOnFailure)284 void *RTDyldMemoryManager::getPointerToNamedFunction(const std::string &Name,
285 bool AbortOnFailure) {
286 uint64_t Addr = getSymbolAddress(Name);
287
288 if (!Addr && AbortOnFailure)
289 report_fatal_error("Program used external function '" + Name +
290 "' which could not be resolved!");
291 return (void*)Addr;
292 }
293
294 } // namespace llvm
295