Line data Source code
1 : //===-- ExternalFunctions.cpp - Implement External Functions --------------===//
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 : // This file contains both code to deal with invoking "external" functions, but
11 : // also contains code that implements "exported" external functions.
12 : //
13 : // There are currently two mechanisms for handling external functions in the
14 : // Interpreter. The first is to implement lle_* wrapper functions that are
15 : // specific to well-known library functions which manually translate the
16 : // arguments from GenericValues and make the call. If such a wrapper does
17 : // not exist, and libffi is available, then the Interpreter will attempt to
18 : // invoke the function using libffi, after finding its address.
19 : //
20 : //===----------------------------------------------------------------------===//
21 :
22 : #include "Interpreter.h"
23 : #include "llvm/ADT/APInt.h"
24 : #include "llvm/ADT/ArrayRef.h"
25 : #include "llvm/Config/config.h" // Detect libffi
26 : #include "llvm/ExecutionEngine/GenericValue.h"
27 : #include "llvm/IR/DataLayout.h"
28 : #include "llvm/IR/DerivedTypes.h"
29 : #include "llvm/IR/Function.h"
30 : #include "llvm/IR/Type.h"
31 : #include "llvm/Support/Casting.h"
32 : #include "llvm/Support/DynamicLibrary.h"
33 : #include "llvm/Support/ErrorHandling.h"
34 : #include "llvm/Support/ManagedStatic.h"
35 : #include "llvm/Support/Mutex.h"
36 : #include "llvm/Support/UniqueLock.h"
37 : #include "llvm/Support/raw_ostream.h"
38 : #include <cassert>
39 : #include <cmath>
40 : #include <csignal>
41 : #include <cstdint>
42 : #include <cstdio>
43 : #include <cstring>
44 : #include <map>
45 : #include <string>
46 : #include <utility>
47 : #include <vector>
48 :
49 : #ifdef HAVE_FFI_CALL
50 : #ifdef HAVE_FFI_H
51 : #include <ffi.h>
52 : #define USE_LIBFFI
53 : #elif HAVE_FFI_FFI_H
54 : #include <ffi/ffi.h>
55 : #define USE_LIBFFI
56 : #endif
57 : #endif
58 :
59 : using namespace llvm;
60 :
61 : static ManagedStatic<sys::Mutex> FunctionsLock;
62 :
63 : typedef GenericValue (*ExFunc)(FunctionType *, ArrayRef<GenericValue>);
64 : static ManagedStatic<std::map<const Function *, ExFunc> > ExportedFunctions;
65 : static ManagedStatic<std::map<std::string, ExFunc> > FuncNames;
66 :
67 : #ifdef USE_LIBFFI
68 : typedef void (*RawFunc)();
69 : static ManagedStatic<std::map<const Function *, RawFunc> > RawFunctions;
70 : #endif
71 :
72 : static Interpreter *TheInterpreter;
73 :
74 82 : static char getTypeID(Type *Ty) {
75 82 : switch (Ty->getTypeID()) {
76 : case Type::VoidTyID: return 'V';
77 : case Type::IntegerTyID:
78 26 : switch (cast<IntegerType>(Ty)->getBitWidth()) {
79 : case 1: return 'o';
80 0 : case 8: return 'B';
81 0 : case 16: return 'S';
82 26 : case 32: return 'I';
83 0 : case 64: return 'L';
84 0 : default: return 'N';
85 : }
86 15 : case Type::FloatTyID: return 'F';
87 15 : case Type::DoubleTyID: return 'D';
88 7 : case Type::PointerTyID: return 'P';
89 0 : case Type::FunctionTyID:return 'M';
90 0 : case Type::StructTyID: return 'T';
91 0 : case Type::ArrayTyID: return 'A';
92 0 : default: return 'U';
93 : }
94 : }
95 :
96 : // Try to find address of external function given a Function object.
97 : // Please note, that interpreter doesn't know how to assemble a
98 : // real call in general case (this is JIT job), that's why it assumes,
99 : // that all external functions has the same (and pretty "general") signature.
100 : // The typical example of such functions are "lle_X_" ones.
101 40 : static ExFunc lookupFunction(const Function *F) {
102 : // Function not found, look it up... start by figuring out what the
103 : // composite function name should be.
104 40 : std::string ExtName = "lle_";
105 : FunctionType *FT = F->getFunctionType();
106 122 : for (unsigned i = 0, e = FT->getNumContainedTypes(); i != e; ++i)
107 164 : ExtName += getTypeID(FT->getContainedType(i));
108 40 : ExtName += ("_" + F->getName()).str();
109 :
110 40 : sys::ScopedLock Writer(*FunctionsLock);
111 40 : ExFunc FnPtr = (*FuncNames)[ExtName];
112 40 : if (!FnPtr)
113 40 : FnPtr = (*FuncNames)[("lle_X_" + F->getName()).str()];
114 40 : if (!FnPtr) // Try calling a generic function... if it exists...
115 14 : FnPtr = (ExFunc)(intptr_t)sys::DynamicLibrary::SearchForAddressOfSymbol(
116 28 : ("lle_X_" + F->getName()).str());
117 40 : if (FnPtr)
118 26 : ExportedFunctions->insert(std::make_pair(F, FnPtr)); // Cache for later
119 40 : return FnPtr;
120 : }
121 :
122 : #ifdef USE_LIBFFI
123 30 : static ffi_type *ffiTypeFor(Type *Ty) {
124 30 : switch (Ty->getTypeID()) {
125 : case Type::VoidTyID: return &ffi_type_void;
126 : case Type::IntegerTyID:
127 : switch (cast<IntegerType>(Ty)->getBitWidth()) {
128 : case 8: return &ffi_type_sint8;
129 0 : case 16: return &ffi_type_sint16;
130 0 : case 32: return &ffi_type_sint32;
131 0 : case 64: return &ffi_type_sint64;
132 : }
133 : case Type::FloatTyID: return &ffi_type_float;
134 15 : case Type::DoubleTyID: return &ffi_type_double;
135 0 : case Type::PointerTyID: return &ffi_type_pointer;
136 : default: break;
137 : }
138 : // TODO: Support other types such as StructTyID, ArrayTyID, OpaqueTyID, etc.
139 0 : report_fatal_error("Type could not be mapped for use with libffi.");
140 : return NULL;
141 : }
142 :
143 16 : static void *ffiValueFor(Type *Ty, const GenericValue &AV,
144 : void *ArgDataPtr) {
145 16 : switch (Ty->getTypeID()) {
146 : case Type::IntegerTyID:
147 : switch (cast<IntegerType>(Ty)->getBitWidth()) {
148 0 : case 8: {
149 : int8_t *I8Ptr = (int8_t *) ArgDataPtr;
150 0 : *I8Ptr = (int8_t) AV.IntVal.getZExtValue();
151 0 : return ArgDataPtr;
152 : }
153 0 : case 16: {
154 : int16_t *I16Ptr = (int16_t *) ArgDataPtr;
155 0 : *I16Ptr = (int16_t) AV.IntVal.getZExtValue();
156 0 : return ArgDataPtr;
157 : }
158 0 : case 32: {
159 : int32_t *I32Ptr = (int32_t *) ArgDataPtr;
160 0 : *I32Ptr = (int32_t) AV.IntVal.getZExtValue();
161 0 : return ArgDataPtr;
162 : }
163 0 : case 64: {
164 : int64_t *I64Ptr = (int64_t *) ArgDataPtr;
165 0 : *I64Ptr = (int64_t) AV.IntVal.getZExtValue();
166 0 : return ArgDataPtr;
167 : }
168 8 : }
169 : case Type::FloatTyID: {
170 : float *FloatPtr = (float *) ArgDataPtr;
171 8 : *FloatPtr = AV.FloatVal;
172 8 : return ArgDataPtr;
173 : }
174 8 : case Type::DoubleTyID: {
175 : double *DoublePtr = (double *) ArgDataPtr;
176 8 : *DoublePtr = AV.DoubleVal;
177 8 : return ArgDataPtr;
178 : }
179 0 : case Type::PointerTyID: {
180 : void **PtrPtr = (void **) ArgDataPtr;
181 0 : *PtrPtr = GVTOP(AV);
182 0 : return ArgDataPtr;
183 : }
184 : default: break;
185 : }
186 : // TODO: Support other types such as StructTyID, ArrayTyID, OpaqueTyID, etc.
187 0 : report_fatal_error("Type value could not be mapped for use with libffi.");
188 : return NULL;
189 : }
190 :
191 14 : static bool ffiInvoke(RawFunc Fn, Function *F, ArrayRef<GenericValue> ArgVals,
192 : const DataLayout &TD, GenericValue &Result) {
193 : ffi_cif cif;
194 : FunctionType *FTy = F->getFunctionType();
195 14 : const unsigned NumArgs = F->arg_size();
196 :
197 : // TODO: We don't have type information about the remaining arguments, because
198 : // this information is never passed into ExecutionEngine::runFunction().
199 14 : if (ArgVals.size() > NumArgs && F->isVarArg()) {
200 0 : report_fatal_error("Calling external var arg function '" + F->getName()
201 : + "' is not supported by the Interpreter.");
202 : }
203 :
204 : unsigned ArgBytes = 0;
205 :
206 14 : std::vector<ffi_type*> args(NumArgs);
207 16 : for (Function::const_arg_iterator A = F->arg_begin(), E = F->arg_end();
208 30 : A != E; ++A) {
209 16 : const unsigned ArgNo = A->getArgNo();
210 16 : Type *ArgTy = FTy->getParamType(ArgNo);
211 32 : args[ArgNo] = ffiTypeFor(ArgTy);
212 16 : ArgBytes += TD.getTypeStoreSize(ArgTy);
213 : }
214 :
215 : SmallVector<uint8_t, 128> ArgData;
216 14 : ArgData.resize(ArgBytes);
217 14 : uint8_t *ArgDataPtr = ArgData.data();
218 14 : SmallVector<void*, 16> values(NumArgs);
219 16 : for (Function::const_arg_iterator A = F->arg_begin(), E = F->arg_end();
220 30 : A != E; ++A) {
221 16 : const unsigned ArgNo = A->getArgNo();
222 16 : Type *ArgTy = FTy->getParamType(ArgNo);
223 32 : values[ArgNo] = ffiValueFor(ArgTy, ArgVals[ArgNo], ArgDataPtr);
224 16 : ArgDataPtr += TD.getTypeStoreSize(ArgTy);
225 : }
226 :
227 14 : Type *RetTy = FTy->getReturnType();
228 14 : ffi_type *rtype = ffiTypeFor(RetTy);
229 :
230 14 : if (ffi_prep_cif(&cif, FFI_DEFAULT_ABI, NumArgs, rtype, &args[0]) == FFI_OK) {
231 : SmallVector<uint8_t, 128> ret;
232 14 : if (RetTy->getTypeID() != Type::VoidTyID)
233 14 : ret.resize(TD.getTypeStoreSize(RetTy));
234 14 : ffi_call(&cif, Fn, ret.data(), values.data());
235 14 : switch (RetTy->getTypeID()) {
236 : case Type::IntegerTyID:
237 : switch (cast<IntegerType>(RetTy)->getBitWidth()) {
238 0 : case 8: Result.IntVal = APInt(8 , *(int8_t *) ret.data()); break;
239 0 : case 16: Result.IntVal = APInt(16, *(int16_t*) ret.data()); break;
240 0 : case 32: Result.IntVal = APInt(32, *(int32_t*) ret.data()); break;
241 0 : case 64: Result.IntVal = APInt(64, *(int64_t*) ret.data()); break;
242 : }
243 : break;
244 7 : case Type::FloatTyID: Result.FloatVal = *(float *) ret.data(); break;
245 7 : case Type::DoubleTyID: Result.DoubleVal = *(double*) ret.data(); break;
246 0 : case Type::PointerTyID: Result.PointerVal = *(void **) ret.data(); break;
247 : default: break;
248 : }
249 : return true;
250 : }
251 :
252 : return false;
253 : }
254 : #endif // USE_LIBFFI
255 :
256 47 : GenericValue Interpreter::callExternalFunction(Function *F,
257 : ArrayRef<GenericValue> ArgVals) {
258 47 : TheInterpreter = this;
259 :
260 47 : unique_lock<sys::Mutex> Guard(*FunctionsLock);
261 :
262 : // Do a lookup to see if the function is in our cache... this should just be a
263 : // deferred annotation!
264 47 : std::map<const Function *, ExFunc>::iterator FI = ExportedFunctions->find(F);
265 47 : if (ExFunc Fn = (FI == ExportedFunctions->end()) ? lookupFunction(F)
266 : : FI->second) {
267 : Guard.unlock();
268 33 : return Fn(F->getFunctionType(), ArgVals);
269 : }
270 :
271 : #ifdef USE_LIBFFI
272 14 : std::map<const Function *, RawFunc>::iterator RF = RawFunctions->find(F);
273 : RawFunc RawFn;
274 14 : if (RF == RawFunctions->end()) {
275 14 : RawFn = (RawFunc)(intptr_t)
276 14 : sys::DynamicLibrary::SearchForAddressOfSymbol(F->getName());
277 14 : if (!RawFn)
278 0 : RawFn = (RawFunc)(intptr_t)getPointerToGlobalIfAvailable(F);
279 14 : if (RawFn != 0)
280 14 : RawFunctions->insert(std::make_pair(F, RawFn)); // Cache for later
281 : } else {
282 0 : RawFn = RF->second;
283 : }
284 :
285 : Guard.unlock();
286 :
287 14 : GenericValue Result;
288 14 : if (RawFn != 0 && ffiInvoke(RawFn, F, ArgVals, getDataLayout(), Result))
289 : return Result;
290 : #endif // USE_LIBFFI
291 :
292 0 : if (F->getName() == "__main")
293 0 : errs() << "Tried to execute an unknown external function: "
294 0 : << *F->getType() << " __main\n";
295 : else
296 0 : report_fatal_error("Tried to execute an unknown external function: " +
297 0 : F->getName());
298 : #ifndef USE_LIBFFI
299 : errs() << "Recompiling LLVM with --enable-libffi might help.\n";
300 : #endif
301 : return GenericValue();
302 : }
303 :
304 : //===----------------------------------------------------------------------===//
305 : // Functions "exported" to the running application...
306 : //
307 :
308 : // void atexit(Function*)
309 0 : static GenericValue lle_X_atexit(FunctionType *FT,
310 : ArrayRef<GenericValue> Args) {
311 : assert(Args.size() == 1);
312 0 : TheInterpreter->addAtExitHandler((Function*)GVTOP(Args[0]));
313 : GenericValue GV;
314 0 : GV.IntVal = 0;
315 0 : return GV;
316 : }
317 :
318 : // void exit(int)
319 19 : static GenericValue lle_X_exit(FunctionType *FT, ArrayRef<GenericValue> Args) {
320 19 : TheInterpreter->exitCalled(Args[0]);
321 0 : return GenericValue();
322 : }
323 :
324 : // void abort(void)
325 0 : static GenericValue lle_X_abort(FunctionType *FT, ArrayRef<GenericValue> Args) {
326 : //FIXME: should we report or raise here?
327 : //report_fatal_error("Interpreted program raised SIGABRT");
328 0 : raise (SIGABRT);
329 0 : return GenericValue();
330 : }
331 :
332 : // int sprintf(char *, const char *, ...) - a very rough implementation to make
333 : // output useful.
334 14 : static GenericValue lle_X_sprintf(FunctionType *FT,
335 : ArrayRef<GenericValue> Args) {
336 14 : char *OutputBuffer = (char *)GVTOP(Args[0]);
337 14 : const char *FmtStr = (const char *)GVTOP(Args[1]);
338 : unsigned ArgNo = 2;
339 :
340 : // printf should return # chars printed. This is completely incorrect, but
341 : // close enough for now.
342 : GenericValue GV;
343 28 : GV.IntVal = APInt(32, strlen(FmtStr));
344 : while (true) {
345 101 : switch (*FmtStr) {
346 14 : case 0: return GV; // Null terminator...
347 76 : default: // Normal nonspecial character
348 76 : sprintf(OutputBuffer++, "%c", *FmtStr++);
349 76 : break;
350 0 : case '\\': { // Handle escape codes
351 0 : sprintf(OutputBuffer, "%c%c", *FmtStr, *(FmtStr+1));
352 0 : FmtStr += 2; OutputBuffer += 2;
353 0 : break;
354 : }
355 11 : case '%': { // Handle format specifiers
356 11 : char FmtBuf[100] = "", Buffer[1000] = "";
357 : char *FB = FmtBuf;
358 11 : *FB++ = *FmtStr++;
359 11 : char Last = *FB++ = *FmtStr++;
360 : unsigned HowLong = 0;
361 67 : while (Last != 'c' && Last != 'd' && Last != 'i' && Last != 'u' &&
362 18 : Last != 'o' && Last != 'x' && Last != 'X' && Last != 'e' &&
363 10 : Last != 'E' && Last != 'g' && Last != 'G' && Last != 'f' &&
364 31 : Last != 'p' && Last != 's' && Last != '%') {
365 10 : if (Last == 'l' || Last == 'L') HowLong++; // Keep track of l's
366 10 : Last = *FB++ = *FmtStr++;
367 : }
368 11 : *FB = 0;
369 :
370 : switch (Last) {
371 0 : case '%':
372 0 : memcpy(Buffer, "%", 2); break;
373 0 : case 'c':
374 0 : sprintf(Buffer, FmtBuf, uint32_t(Args[ArgNo++].IntVal.getZExtValue()));
375 0 : break;
376 11 : case 'd': case 'i':
377 : case 'u': case 'o':
378 : case 'x': case 'X':
379 11 : if (HowLong >= 1) {
380 2 : if (HowLong == 1 &&
381 2 : TheInterpreter->getDataLayout().getPointerSizeInBits() == 64 &&
382 : sizeof(long) < sizeof(int64_t)) {
383 : // Make sure we use %lld with a 64 bit argument because we might be
384 : // compiling LLI on a 32 bit compiler.
385 : unsigned Size = strlen(FmtBuf);
386 : FmtBuf[Size] = FmtBuf[Size-1];
387 : FmtBuf[Size+1] = 0;
388 : FmtBuf[Size-1] = 'l';
389 : }
390 4 : sprintf(Buffer, FmtBuf, Args[ArgNo++].IntVal.getZExtValue());
391 : } else
392 18 : sprintf(Buffer, FmtBuf,uint32_t(Args[ArgNo++].IntVal.getZExtValue()));
393 : break;
394 0 : case 'e': case 'E': case 'g': case 'G': case 'f':
395 0 : sprintf(Buffer, FmtBuf, Args[ArgNo++].DoubleVal); break;
396 0 : case 'p':
397 0 : sprintf(Buffer, FmtBuf, (void*)GVTOP(Args[ArgNo++])); break;
398 0 : case 's':
399 0 : sprintf(Buffer, FmtBuf, (char*)GVTOP(Args[ArgNo++])); break;
400 0 : default:
401 0 : errs() << "<unknown printf code '" << *FmtStr << "'!>";
402 0 : ArgNo++; break;
403 : }
404 11 : size_t Len = strlen(Buffer);
405 11 : memcpy(OutputBuffer, Buffer, Len + 1);
406 11 : OutputBuffer += Len;
407 : }
408 11 : break;
409 : }
410 : }
411 : return GV;
412 : }
413 :
414 : // int printf(const char *, ...) - a very rough implementation to make output
415 : // useful.
416 14 : static GenericValue lle_X_printf(FunctionType *FT,
417 : ArrayRef<GenericValue> Args) {
418 : char Buffer[10000];
419 14 : std::vector<GenericValue> NewArgs;
420 14 : NewArgs.push_back(PTOGV((void*)&Buffer[0]));
421 14 : NewArgs.insert(NewArgs.end(), Args.begin(), Args.end());
422 14 : GenericValue GV = lle_X_sprintf(FT, NewArgs);
423 14 : outs() << Buffer;
424 14 : return GV;
425 : }
426 :
427 : // int sscanf(const char *format, ...);
428 0 : static GenericValue lle_X_sscanf(FunctionType *FT,
429 : ArrayRef<GenericValue> args) {
430 : assert(args.size() < 10 && "Only handle up to 10 args to sscanf right now!");
431 :
432 : char *Args[10];
433 0 : for (unsigned i = 0; i < args.size(); ++i)
434 0 : Args[i] = (char*)GVTOP(args[i]);
435 :
436 : GenericValue GV;
437 0 : GV.IntVal = APInt(32, sscanf(Args[0], Args[1], Args[2], Args[3], Args[4],
438 : Args[5], Args[6], Args[7], Args[8], Args[9]));
439 0 : return GV;
440 : }
441 :
442 : // int scanf(const char *format, ...);
443 0 : static GenericValue lle_X_scanf(FunctionType *FT, ArrayRef<GenericValue> args) {
444 : assert(args.size() < 10 && "Only handle up to 10 args to scanf right now!");
445 :
446 : char *Args[10];
447 0 : for (unsigned i = 0; i < args.size(); ++i)
448 0 : Args[i] = (char*)GVTOP(args[i]);
449 :
450 : GenericValue GV;
451 0 : GV.IntVal = APInt(32, scanf( Args[0], Args[1], Args[2], Args[3], Args[4],
452 : Args[5], Args[6], Args[7], Args[8], Args[9]));
453 0 : return GV;
454 : }
455 :
456 : // int fprintf(FILE *, const char *, ...) - a very rough implementation to make
457 : // output useful.
458 0 : static GenericValue lle_X_fprintf(FunctionType *FT,
459 : ArrayRef<GenericValue> Args) {
460 : assert(Args.size() >= 2);
461 : char Buffer[10000];
462 0 : std::vector<GenericValue> NewArgs;
463 0 : NewArgs.push_back(PTOGV(Buffer));
464 0 : NewArgs.insert(NewArgs.end(), Args.begin()+1, Args.end());
465 0 : GenericValue GV = lle_X_sprintf(FT, NewArgs);
466 :
467 0 : fputs(Buffer, (FILE *) GVTOP(Args[0]));
468 0 : return GV;
469 : }
470 :
471 0 : static GenericValue lle_X_memset(FunctionType *FT,
472 : ArrayRef<GenericValue> Args) {
473 0 : int val = (int)Args[1].IntVal.getSExtValue();
474 : size_t len = (size_t)Args[2].IntVal.getZExtValue();
475 0 : memset((void *)GVTOP(Args[0]), val, len);
476 : // llvm.memset.* returns void, lle_X_* returns GenericValue,
477 : // so here we return GenericValue with IntVal set to zero
478 : GenericValue GV;
479 0 : GV.IntVal = 0;
480 0 : return GV;
481 : }
482 :
483 0 : static GenericValue lle_X_memcpy(FunctionType *FT,
484 : ArrayRef<GenericValue> Args) {
485 0 : memcpy(GVTOP(Args[0]), GVTOP(Args[1]),
486 0 : (size_t)(Args[2].IntVal.getLimitedValue()));
487 :
488 : // llvm.memcpy* returns void, lle_X_* returns GenericValue,
489 : // so here we return GenericValue with IntVal set to zero
490 : GenericValue GV;
491 0 : GV.IntVal = 0;
492 0 : return GV;
493 : }
494 :
495 24 : void Interpreter::initializeExternalFunctions() {
496 24 : sys::ScopedLock Writer(*FunctionsLock);
497 24 : (*FuncNames)["lle_X_atexit"] = lle_X_atexit;
498 24 : (*FuncNames)["lle_X_exit"] = lle_X_exit;
499 24 : (*FuncNames)["lle_X_abort"] = lle_X_abort;
500 :
501 24 : (*FuncNames)["lle_X_printf"] = lle_X_printf;
502 24 : (*FuncNames)["lle_X_sprintf"] = lle_X_sprintf;
503 24 : (*FuncNames)["lle_X_sscanf"] = lle_X_sscanf;
504 24 : (*FuncNames)["lle_X_scanf"] = lle_X_scanf;
505 24 : (*FuncNames)["lle_X_fprintf"] = lle_X_fprintf;
506 24 : (*FuncNames)["lle_X_memset"] = lle_X_memset;
507 24 : (*FuncNames)["lle_X_memcpy"] = lle_X_memcpy;
508 24 : }
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