1//===-- RTDyldMemoryManager.cpp - Memory manager for MC-JIT -----*- 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// Implementation of the runtime dynamic memory manager base class.
10//
11//===----------------------------------------------------------------------===//
12
13#include "llvm/Config/config.h"
14#include "llvm/ExecutionEngine/RTDyldMemoryManager.h"
15#include "llvm/Support/Compiler.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#include <fcntl.h>
24#include <sys/stat.h>
25#include <unistd.h>
26#endif
27
28namespace llvm {
29
30RTDyldMemoryManager::~RTDyldMemoryManager() = default;
31
32#if defined(HAVE_REGISTER_FRAME) && defined(HAVE_DEREGISTER_FRAME) && \
33 !defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__)
34extern "C" void __register_frame(void *);
35extern "C" void __deregister_frame(void *);
36#else
37// The building compiler does not have __(de)register_frame but
38// it may be found at runtime in a dynamically-loaded library.
39// For example, this happens when building LLVM with Visual C++
40// but using the MingW runtime.
41static void __register_frame(void *p) {
42 static bool Searched = false;
43 static void (*rf)(void *) = 0;
44
45 if (!Searched) {
46 Searched = true;
47 *(void **)&rf =
48 llvm::sys::DynamicLibrary::SearchForAddressOfSymbol("__register_frame");
49 }
50 if (rf)
51 rf(p);
52}
53
54static void __deregister_frame(void *p) {
55 static bool Searched = false;
56 static void (*df)(void *) = 0;
57
58 if (!Searched) {
59 Searched = true;
60 *(void **)&df = llvm::sys::DynamicLibrary::SearchForAddressOfSymbol(
61 "__deregister_frame");
62 }
63 if (df)
64 df(p);
65}
66#endif
67
68/* libgcc and libunwind __register_frame behave differently. We use the presence
69 * of __unw_add_dynamic_fde to detect libunwind. */
70#if defined(HAVE_UNW_ADD_DYNAMIC_FDE) || defined(__APPLE__)
71
72static const char *processFDE(const char *Entry, bool isDeregister) {
73 const char *P = Entry;
74 uint32_t Length = *((const uint32_t *)P);
75 P += 4;
76 uint32_t Offset = *((const uint32_t *)P);
77 if (Offset != 0) {
78 if (isDeregister)
79 __deregister_frame(const_cast<char *>(Entry));
80 else
81 __register_frame(const_cast<char *>(Entry));
82 }
83 return P + Length;
84}
85
86// This implementation handles frame registration for local targets.
87// Memory managers for remote targets should re-implement this function
88// and use the LoadAddr parameter.
89void RTDyldMemoryManager::registerEHFramesInProcess(uint8_t *Addr,
90 size_t Size) {
91 // On OS X OS X __register_frame takes a single FDE as an argument.
92 // See http://lists.llvm.org/pipermail/llvm-dev/2013-April/061737.html
93 // and projects/libunwind/src/UnwindLevel1-gcc-ext.c.
94 const char *P = (const char *)Addr;
95 const char *End = P + Size;
96 while (P != End)
97 P = processFDE(P, false);
98}
99
100void RTDyldMemoryManager::deregisterEHFramesInProcess(uint8_t *Addr,
101 size_t Size) {
102 const char *P = (const char *)Addr;
103 const char *End = P + Size;
104 while (P != End)
105 P = processFDE(P, true);
106}
107
108#else
109
110void RTDyldMemoryManager::registerEHFramesInProcess(uint8_t *Addr,
111 size_t Size) {
112 // On Linux __register_frame takes a single argument:
113 // a pointer to the start of the .eh_frame section.
114
115 // How can it find the end? Because crtendS.o is linked
116 // in and it has an .eh_frame section with four zero chars.
117 __register_frame(Addr);
118}
119
120void RTDyldMemoryManager::deregisterEHFramesInProcess(uint8_t *Addr,
121 size_t Size) {
122 __deregister_frame(Addr);
123}
124
125#endif
126
127void RTDyldMemoryManager::registerEHFrames(uint8_t *Addr, uint64_t LoadAddr,
128 size_t Size) {
129 registerEHFramesInProcess(Addr, Size);
130 EHFrames.push_back(x: {.Addr: Addr, .Size: Size});
131}
132
133void RTDyldMemoryManager::deregisterEHFrames() {
134 for (auto &Frame : EHFrames)
135 deregisterEHFramesInProcess(Addr: Frame.Addr, Size: Frame.Size);
136 EHFrames.clear();
137}
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
213#if defined(__linux__) && defined(__GLIBC__) && \
214 (defined(__i386__) || defined(__x86_64__))
215extern "C" LLVM_ATTRIBUTE_WEAK void __morestack();
216#endif
217
218uint64_t
219RTDyldMemoryManager::getSymbolAddressInProcess(const std::string &Name) {
220 // This implementation assumes that the host program is the target.
221 // Clients generating code for a remote target should implement their own
222 // memory manager.
223#if defined(__linux__) && defined(__GLIBC__)
224 //===--------------------------------------------------------------------===//
225 // Function stubs that are invoked instead of certain library calls
226 //
227 // Force the following functions to be linked in to anything that uses the
228 // JIT. This is a hack designed to work around the all-too-clever Glibc
229 // strategy of making these functions work differently when inlined vs. when
230 // not inlined, and hiding their real definitions in a separate archive file
231 // that the dynamic linker can't see. For more info, search for
232 // 'libc_nonshared.a' on Google, or read http://llvm.org/PR274.
233 if (Name == "stat") return (uint64_t)&stat;
234 if (Name == "fstat") return (uint64_t)&fstat;
235 if (Name == "lstat") return (uint64_t)&lstat;
236 if (Name == "stat64") return (uint64_t)&stat64;
237 if (Name == "fstat64") return (uint64_t)&fstat64;
238 if (Name == "lstat64") return (uint64_t)&lstat64;
239 if (Name == "atexit") return (uint64_t)&atexit;
240 if (Name == "mknod") return (uint64_t)&mknod;
241
242#if defined(__i386__) || defined(__x86_64__)
243 // __morestack lives in libgcc, a static library.
244 if (&__morestack && Name == "__morestack")
245 return (uint64_t)&__morestack;
246#endif
247#endif // __linux__ && __GLIBC__
248
249 // See ARM_MATH_IMPORTS definition for explanation
250#if defined(__BIONIC__) && defined(__arm__)
251 if (Name.compare(0, 8, "__aeabi_") == 0) {
252 // Check if the user has requested any of the functions listed in
253 // ARM_MATH_IMPORTS, and if so redirect to the statically linked symbol.
254#define ARM_MATH_CHECK(fn) if (Name == #fn) return (uint64_t)&fn;
255 ARM_MATH_IMPORTS(ARM_MATH_CHECK)
256#undef ARM_MATH_CHECK
257 }
258#endif
259
260 // We should not invoke parent's ctors/dtors from generated main()!
261 // On Mingw and Cygwin, the symbol __main is resolved to
262 // callee's(eg. tools/lli) one, to invoke wrong duplicated ctors
263 // (and register wrong callee's dtors with atexit(3)).
264 // We expect ExecutionEngine::runStaticConstructorsDestructors()
265 // is called before ExecutionEngine::runFunctionAsMain() is called.
266 if (Name == "__main") return (uint64_t)&jit_noop;
267
268 const char *NameStr = Name.c_str();
269
270 // DynamicLibrary::SearchForAddressOfSymbol expects an unmangled 'C' symbol
271 // name so ff we're on Darwin, strip the leading '_' off.
272#ifdef __APPLE__
273 if (NameStr[0] == '_')
274 ++NameStr;
275#endif
276
277 return (uint64_t)sys::DynamicLibrary::SearchForAddressOfSymbol(symbolName: NameStr);
278}
279
280void *RTDyldMemoryManager::getPointerToNamedFunction(const std::string &Name,
281 bool AbortOnFailure) {
282 uint64_t Addr = getSymbolAddress(Name);
283
284 if (!Addr && AbortOnFailure)
285 report_fatal_error(reason: Twine("Program used external function '") + Name +
286 "' which could not be resolved!");
287
288 return (void*)Addr;
289}
290
291void RTDyldMemoryManager::anchor() {}
292void MCJITMemoryManager::anchor() {}
293} // namespace llvm
294