LLVM 17.0.0git
ExternalFunctions.cpp
Go to the documentation of this file.
1//===-- ExternalFunctions.cpp - Implement External Functions --------------===//
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// This file contains both code to deal with invoking "external" functions, but
10// also contains code that implements "exported" external functions.
11//
12// There are currently two mechanisms for handling external functions in the
13// Interpreter. The first is to implement lle_* wrapper functions that are
14// specific to well-known library functions which manually translate the
15// arguments from GenericValues and make the call. If such a wrapper does
16// not exist, and libffi is available, then the Interpreter will attempt to
17// invoke the function using libffi, after finding its address.
18//
19//===----------------------------------------------------------------------===//
20
21#include "Interpreter.h"
22#include "llvm/ADT/APInt.h"
23#include "llvm/ADT/ArrayRef.h"
24#include "llvm/Config/config.h" // Detect libffi
26#include "llvm/IR/DataLayout.h"
28#include "llvm/IR/Function.h"
29#include "llvm/IR/Type.h"
33#include "llvm/Support/Mutex.h"
35#include <cassert>
36#include <cmath>
37#include <csignal>
38#include <cstdint>
39#include <cstdio>
40#include <cstring>
41#include <map>
42#include <mutex>
43#include <string>
44#include <utility>
45#include <vector>
46
47#ifdef HAVE_FFI_CALL
48#ifdef HAVE_FFI_H
49#include <ffi.h>
50#define USE_LIBFFI
51#elif HAVE_FFI_FFI_H
52#include <ffi/ffi.h>
53#define USE_LIBFFI
54#endif
55#endif
56
57using namespace llvm;
58
59namespace {
60
62typedef void (*RawFunc)();
63
64struct Functions {
65 sys::Mutex Lock;
66 std::map<const Function *, ExFunc> ExportedFunctions;
67 std::map<std::string, ExFunc> FuncNames;
68#ifdef USE_LIBFFI
69 std::map<const Function *, RawFunc> RawFunctions;
70#endif
71};
72
73Functions &getFunctions() {
74 static Functions F;
75 return F;
76}
77
78} // anonymous namespace
79
81
82static char getTypeID(Type *Ty) {
83 switch (Ty->getTypeID()) {
84 case Type::VoidTyID: return 'V';
86 switch (cast<IntegerType>(Ty)->getBitWidth()) {
87 case 1: return 'o';
88 case 8: return 'B';
89 case 16: return 'S';
90 case 32: return 'I';
91 case 64: return 'L';
92 default: return 'N';
93 }
94 case Type::FloatTyID: return 'F';
95 case Type::DoubleTyID: return 'D';
96 case Type::PointerTyID: return 'P';
97 case Type::FunctionTyID:return 'M';
98 case Type::StructTyID: return 'T';
99 case Type::ArrayTyID: return 'A';
100 default: return 'U';
101 }
102}
103
104// Try to find address of external function given a Function object.
105// Please note, that interpreter doesn't know how to assemble a
106// real call in general case (this is JIT job), that's why it assumes,
107// that all external functions has the same (and pretty "general") signature.
108// The typical example of such functions are "lle_X_" ones.
109static ExFunc lookupFunction(const Function *F) {
110 // Function not found, look it up... start by figuring out what the
111 // composite function name should be.
112 std::string ExtName = "lle_";
113 FunctionType *FT = F->getFunctionType();
114 ExtName += getTypeID(FT->getReturnType());
115 for (Type *T : FT->params())
116 ExtName += getTypeID(T);
117 ExtName += ("_" + F->getName()).str();
118
119 auto &Fns = getFunctions();
120 sys::ScopedLock Writer(Fns.Lock);
121 ExFunc FnPtr = Fns.FuncNames[ExtName];
122 if (!FnPtr)
123 FnPtr = Fns.FuncNames[("lle_X_" + F->getName()).str()];
124 if (!FnPtr) // Try calling a generic function... if it exists...
126 ("lle_X_" + F->getName()).str());
127 if (FnPtr)
128 Fns.ExportedFunctions.insert(std::make_pair(F, FnPtr)); // Cache for later
129 return FnPtr;
130}
131
132#ifdef USE_LIBFFI
133static ffi_type *ffiTypeFor(Type *Ty) {
134 switch (Ty->getTypeID()) {
135 case Type::VoidTyID: return &ffi_type_void;
137 switch (cast<IntegerType>(Ty)->getBitWidth()) {
138 case 8: return &ffi_type_sint8;
139 case 16: return &ffi_type_sint16;
140 case 32: return &ffi_type_sint32;
141 case 64: return &ffi_type_sint64;
142 }
143 llvm_unreachable("Unhandled integer type bitwidth");
144 case Type::FloatTyID: return &ffi_type_float;
145 case Type::DoubleTyID: return &ffi_type_double;
146 case Type::PointerTyID: return &ffi_type_pointer;
147 default: break;
148 }
149 // TODO: Support other types such as StructTyID, ArrayTyID, OpaqueTyID, etc.
150 report_fatal_error("Type could not be mapped for use with libffi.");
151 return NULL;
152}
153
154static void *ffiValueFor(Type *Ty, const GenericValue &AV,
155 void *ArgDataPtr) {
156 switch (Ty->getTypeID()) {
158 switch (cast<IntegerType>(Ty)->getBitWidth()) {
159 case 8: {
160 int8_t *I8Ptr = (int8_t *) ArgDataPtr;
161 *I8Ptr = (int8_t) AV.IntVal.getZExtValue();
162 return ArgDataPtr;
163 }
164 case 16: {
165 int16_t *I16Ptr = (int16_t *) ArgDataPtr;
166 *I16Ptr = (int16_t) AV.IntVal.getZExtValue();
167 return ArgDataPtr;
168 }
169 case 32: {
170 int32_t *I32Ptr = (int32_t *) ArgDataPtr;
171 *I32Ptr = (int32_t) AV.IntVal.getZExtValue();
172 return ArgDataPtr;
173 }
174 case 64: {
175 int64_t *I64Ptr = (int64_t *) ArgDataPtr;
176 *I64Ptr = (int64_t) AV.IntVal.getZExtValue();
177 return ArgDataPtr;
178 }
179 }
180 llvm_unreachable("Unhandled integer type bitwidth");
181 case Type::FloatTyID: {
182 float *FloatPtr = (float *) ArgDataPtr;
183 *FloatPtr = AV.FloatVal;
184 return ArgDataPtr;
185 }
186 case Type::DoubleTyID: {
187 double *DoublePtr = (double *) ArgDataPtr;
188 *DoublePtr = AV.DoubleVal;
189 return ArgDataPtr;
190 }
191 case Type::PointerTyID: {
192 void **PtrPtr = (void **) ArgDataPtr;
193 *PtrPtr = GVTOP(AV);
194 return ArgDataPtr;
195 }
196 default: break;
197 }
198 // TODO: Support other types such as StructTyID, ArrayTyID, OpaqueTyID, etc.
199 report_fatal_error("Type value could not be mapped for use with libffi.");
200 return NULL;
201}
202
203static bool ffiInvoke(RawFunc Fn, Function *F, ArrayRef<GenericValue> ArgVals,
204 const DataLayout &TD, GenericValue &Result) {
205 ffi_cif cif;
206 FunctionType *FTy = F->getFunctionType();
207 const unsigned NumArgs = F->arg_size();
208
209 // TODO: We don't have type information about the remaining arguments, because
210 // this information is never passed into ExecutionEngine::runFunction().
211 if (ArgVals.size() > NumArgs && F->isVarArg()) {
212 report_fatal_error("Calling external var arg function '" + F->getName()
213 + "' is not supported by the Interpreter.");
214 }
215
216 unsigned ArgBytes = 0;
217
218 std::vector<ffi_type*> args(NumArgs);
219 for (Function::const_arg_iterator A = F->arg_begin(), E = F->arg_end();
220 A != E; ++A) {
221 const unsigned ArgNo = A->getArgNo();
222 Type *ArgTy = FTy->getParamType(ArgNo);
223 args[ArgNo] = ffiTypeFor(ArgTy);
224 ArgBytes += TD.getTypeStoreSize(ArgTy);
225 }
226
228 ArgData.resize(ArgBytes);
229 uint8_t *ArgDataPtr = ArgData.data();
231 for (Function::const_arg_iterator A = F->arg_begin(), E = F->arg_end();
232 A != E; ++A) {
233 const unsigned ArgNo = A->getArgNo();
234 Type *ArgTy = FTy->getParamType(ArgNo);
235 values[ArgNo] = ffiValueFor(ArgTy, ArgVals[ArgNo], ArgDataPtr);
236 ArgDataPtr += TD.getTypeStoreSize(ArgTy);
237 }
238
239 Type *RetTy = FTy->getReturnType();
240 ffi_type *rtype = ffiTypeFor(RetTy);
241
242 if (ffi_prep_cif(&cif, FFI_DEFAULT_ABI, NumArgs, rtype, args.data()) ==
243 FFI_OK) {
245 if (RetTy->getTypeID() != Type::VoidTyID)
247 ffi_call(&cif, Fn, ret.data(), values.data());
248 switch (RetTy->getTypeID()) {
250 switch (cast<IntegerType>(RetTy)->getBitWidth()) {
251 case 8: Result.IntVal = APInt(8 , *(int8_t *) ret.data()); break;
252 case 16: Result.IntVal = APInt(16, *(int16_t*) ret.data()); break;
253 case 32: Result.IntVal = APInt(32, *(int32_t*) ret.data()); break;
254 case 64: Result.IntVal = APInt(64, *(int64_t*) ret.data()); break;
255 }
256 break;
257 case Type::FloatTyID: Result.FloatVal = *(float *) ret.data(); break;
258 case Type::DoubleTyID: Result.DoubleVal = *(double*) ret.data(); break;
259 case Type::PointerTyID: Result.PointerVal = *(void **) ret.data(); break;
260 default: break;
261 }
262 return true;
263 }
264
265 return false;
266}
267#endif // USE_LIBFFI
268
270 ArrayRef<GenericValue> ArgVals) {
271 TheInterpreter = this;
272
273 auto &Fns = getFunctions();
274 std::unique_lock<sys::Mutex> Guard(Fns.Lock);
275
276 // Do a lookup to see if the function is in our cache... this should just be a
277 // deferred annotation!
278 std::map<const Function *, ExFunc>::iterator FI =
279 Fns.ExportedFunctions.find(F);
280 if (ExFunc Fn = (FI == Fns.ExportedFunctions.end()) ? lookupFunction(F)
281 : FI->second) {
282 Guard.unlock();
283 return Fn(F->getFunctionType(), ArgVals);
284 }
285
286#ifdef USE_LIBFFI
287 std::map<const Function *, RawFunc>::iterator RF = Fns.RawFunctions.find(F);
288 RawFunc RawFn;
289 if (RF == Fns.RawFunctions.end()) {
290 RawFn = (RawFunc)(intptr_t)
291 sys::DynamicLibrary::SearchForAddressOfSymbol(std::string(F->getName()));
292 if (!RawFn)
293 RawFn = (RawFunc)(intptr_t)getPointerToGlobalIfAvailable(F);
294 if (RawFn != 0)
295 Fns.RawFunctions.insert(std::make_pair(F, RawFn)); // Cache for later
296 } else {
297 RawFn = RF->second;
298 }
299
300 Guard.unlock();
301
302 GenericValue Result;
303 if (RawFn != 0 && ffiInvoke(RawFn, F, ArgVals, getDataLayout(), Result))
304 return Result;
305#endif // USE_LIBFFI
306
307 if (F->getName() == "__main")
308 errs() << "Tried to execute an unknown external function: "
309 << *F->getType() << " __main\n";
310 else
311 report_fatal_error("Tried to execute an unknown external function: " +
312 F->getName());
313#ifndef USE_LIBFFI
314 errs() << "Recompiling LLVM with --enable-libffi might help.\n";
315#endif
316 return GenericValue();
317}
318
319//===----------------------------------------------------------------------===//
320// Functions "exported" to the running application...
321//
322
323// void atexit(Function*)
326 assert(Args.size() == 1);
328 GenericValue GV;
329 GV.IntVal = 0;
330 return GV;
331}
332
333// void exit(int)
335 TheInterpreter->exitCalled(Args[0]);
336 return GenericValue();
337}
338
339// void abort(void)
341 //FIXME: should we report or raise here?
342 //report_fatal_error("Interpreted program raised SIGABRT");
343 raise (SIGABRT);
344 return GenericValue();
345}
346
347// int sprintf(char *, const char *, ...) - a very rough implementation to make
348// output useful.
351 char *OutputBuffer = (char *)GVTOP(Args[0]);
352 const char *FmtStr = (const char *)GVTOP(Args[1]);
353 unsigned ArgNo = 2;
354
355 // printf should return # chars printed. This is completely incorrect, but
356 // close enough for now.
357 GenericValue GV;
358 GV.IntVal = APInt(32, strlen(FmtStr));
359 while (true) {
360 switch (*FmtStr) {
361 case 0: return GV; // Null terminator...
362 default: // Normal nonspecial character
363 sprintf(OutputBuffer++, "%c", *FmtStr++);
364 break;
365 case '\\': { // Handle escape codes
366 sprintf(OutputBuffer, "%c%c", *FmtStr, *(FmtStr+1));
367 FmtStr += 2; OutputBuffer += 2;
368 break;
369 }
370 case '%': { // Handle format specifiers
371 char FmtBuf[100] = "", Buffer[1000] = "";
372 char *FB = FmtBuf;
373 *FB++ = *FmtStr++;
374 char Last = *FB++ = *FmtStr++;
375 unsigned HowLong = 0;
376 while (Last != 'c' && Last != 'd' && Last != 'i' && Last != 'u' &&
377 Last != 'o' && Last != 'x' && Last != 'X' && Last != 'e' &&
378 Last != 'E' && Last != 'g' && Last != 'G' && Last != 'f' &&
379 Last != 'p' && Last != 's' && Last != '%') {
380 if (Last == 'l' || Last == 'L') HowLong++; // Keep track of l's
381 Last = *FB++ = *FmtStr++;
382 }
383 *FB = 0;
384
385 switch (Last) {
386 case '%':
387 memcpy(Buffer, "%", 2); break;
388 case 'c':
389 sprintf(Buffer, FmtBuf, uint32_t(Args[ArgNo++].IntVal.getZExtValue()));
390 break;
391 case 'd': case 'i':
392 case 'u': case 'o':
393 case 'x': case 'X':
394 if (HowLong >= 1) {
395 if (HowLong == 1 &&
397 sizeof(long) < sizeof(int64_t)) {
398 // Make sure we use %lld with a 64 bit argument because we might be
399 // compiling LLI on a 32 bit compiler.
400 unsigned Size = strlen(FmtBuf);
401 FmtBuf[Size] = FmtBuf[Size-1];
402 FmtBuf[Size+1] = 0;
403 FmtBuf[Size-1] = 'l';
404 }
405 sprintf(Buffer, FmtBuf, Args[ArgNo++].IntVal.getZExtValue());
406 } else
407 sprintf(Buffer, FmtBuf,uint32_t(Args[ArgNo++].IntVal.getZExtValue()));
408 break;
409 case 'e': case 'E': case 'g': case 'G': case 'f':
410 sprintf(Buffer, FmtBuf, Args[ArgNo++].DoubleVal); break;
411 case 'p':
412 sprintf(Buffer, FmtBuf, (void*)GVTOP(Args[ArgNo++])); break;
413 case 's':
414 sprintf(Buffer, FmtBuf, (char*)GVTOP(Args[ArgNo++])); break;
415 default:
416 errs() << "<unknown printf code '" << *FmtStr << "'!>";
417 ArgNo++; break;
418 }
419 size_t Len = strlen(Buffer);
420 memcpy(OutputBuffer, Buffer, Len + 1);
421 OutputBuffer += Len;
422 }
423 break;
424 }
425 }
426 return GV;
427}
428
429// int printf(const char *, ...) - a very rough implementation to make output
430// useful.
433 char Buffer[10000];
434 std::vector<GenericValue> NewArgs;
435 NewArgs.push_back(PTOGV((void*)&Buffer[0]));
436 llvm::append_range(NewArgs, Args);
437 GenericValue GV = lle_X_sprintf(FT, NewArgs);
438 outs() << Buffer;
439 return GV;
440}
441
442// int sscanf(const char *format, ...);
445 assert(args.size() < 10 && "Only handle up to 10 args to sscanf right now!");
446
447 char *Args[10];
448 for (unsigned i = 0; i < args.size(); ++i)
449 Args[i] = (char*)GVTOP(args[i]);
450
451 GenericValue GV;
452 GV.IntVal = APInt(32, sscanf(Args[0], Args[1], Args[2], Args[3], Args[4],
453 Args[5], Args[6], Args[7], Args[8], Args[9]));
454 return GV;
455}
456
457// int scanf(const char *format, ...);
459 assert(args.size() < 10 && "Only handle up to 10 args to scanf right now!");
460
461 char *Args[10];
462 for (unsigned i = 0; i < args.size(); ++i)
463 Args[i] = (char*)GVTOP(args[i]);
464
465 GenericValue GV;
466 GV.IntVal = APInt(32, scanf( Args[0], Args[1], Args[2], Args[3], Args[4],
467 Args[5], Args[6], Args[7], Args[8], Args[9]));
468 return GV;
469}
470
471// int fprintf(FILE *, const char *, ...) - a very rough implementation to make
472// output useful.
475 assert(Args.size() >= 2);
476 char Buffer[10000];
477 std::vector<GenericValue> NewArgs;
478 NewArgs.push_back(PTOGV(Buffer));
479 NewArgs.insert(NewArgs.end(), Args.begin()+1, Args.end());
480 GenericValue GV = lle_X_sprintf(FT, NewArgs);
481
482 fputs(Buffer, (FILE *) GVTOP(Args[0]));
483 return GV;
484}
485
488 int val = (int)Args[1].IntVal.getSExtValue();
489 size_t len = (size_t)Args[2].IntVal.getZExtValue();
490 memset((void *)GVTOP(Args[0]), val, len);
491 // llvm.memset.* returns void, lle_X_* returns GenericValue,
492 // so here we return GenericValue with IntVal set to zero
493 GenericValue GV;
494 GV.IntVal = 0;
495 return GV;
496}
497
500 memcpy(GVTOP(Args[0]), GVTOP(Args[1]),
501 (size_t)(Args[2].IntVal.getLimitedValue()));
502
503 // llvm.memcpy* returns void, lle_X_* returns GenericValue,
504 // so here we return GenericValue with IntVal set to zero
505 GenericValue GV;
506 GV.IntVal = 0;
507 return GV;
508}
509
510void Interpreter::initializeExternalFunctions() {
511 auto &Fns = getFunctions();
512 sys::ScopedLock Writer(Fns.Lock);
513 Fns.FuncNames["lle_X_atexit"] = lle_X_atexit;
514 Fns.FuncNames["lle_X_exit"] = lle_X_exit;
515 Fns.FuncNames["lle_X_abort"] = lle_X_abort;
516
517 Fns.FuncNames["lle_X_printf"] = lle_X_printf;
518 Fns.FuncNames["lle_X_sprintf"] = lle_X_sprintf;
519 Fns.FuncNames["lle_X_sscanf"] = lle_X_sscanf;
520 Fns.FuncNames["lle_X_scanf"] = lle_X_scanf;
521 Fns.FuncNames["lle_X_fprintf"] = lle_X_fprintf;
522 Fns.FuncNames["lle_X_memset"] = lle_X_memset;
523 Fns.FuncNames["lle_X_memcpy"] = lle_X_memcpy;
524}
This file implements a class to represent arbitrary precision integral constant values and operations...
static GCRegistry::Add< ErlangGC > A("erlang", "erlang-compatible garbage collector")
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
return RetTy
Mark the given Function as meaning that it cannot be changed in any way mark any values that are used as this function s parameters or by its return values(according to Uses) live as well. void DeadArgumentEliminationPass
uint64_t Size
static ExFunc lookupFunction(const Function *F)
static Interpreter * TheInterpreter
static GenericValue lle_X_memset(FunctionType *FT, ArrayRef< GenericValue > Args)
static char getTypeID(Type *Ty)
static GenericValue lle_X_fprintf(FunctionType *FT, ArrayRef< GenericValue > Args)
static GenericValue lle_X_scanf(FunctionType *FT, ArrayRef< GenericValue > args)
static GenericValue lle_X_printf(FunctionType *FT, ArrayRef< GenericValue > Args)
static GenericValue lle_X_memcpy(FunctionType *FT, ArrayRef< GenericValue > Args)
static GenericValue lle_X_atexit(FunctionType *FT, ArrayRef< GenericValue > Args)
static GenericValue lle_X_sscanf(FunctionType *FT, ArrayRef< GenericValue > args)
static GenericValue lle_X_abort(FunctionType *FT, ArrayRef< GenericValue > Args)
static GenericValue lle_X_exit(FunctionType *FT, ArrayRef< GenericValue > Args)
static GenericValue lle_X_sprintf(FunctionType *FT, ArrayRef< GenericValue > Args)
#define F(x, y, z)
Definition: MD5.cpp:55
nvptx lower args
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
static unsigned getBitWidth(Type *Ty, const DataLayout &DL)
Returns the bitwidth of the given scalar or pointer type.
Class for arbitrary precision integers.
Definition: APInt.h:75
uint64_t getZExtValue() const
Get zero extended value.
Definition: APInt.h:1494
This class represents an incoming formal argument to a Function.
Definition: Argument.h:28
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory),...
Definition: ArrayRef.h:41
size_t size() const
size - Get the array size.
Definition: ArrayRef.h:163
A parsed version of the target data layout string in and methods for querying it.
Definition: DataLayout.h:114
unsigned getPointerSizeInBits(unsigned AS=0) const
Layout pointer size, in bits FIXME: The defaults need to be removed once all of the backends/clients ...
Definition: DataLayout.h:413
TypeSize getTypeStoreSize(Type *Ty) const
Returns the maximum number of bytes that may be overwritten by storing the specified type.
Definition: DataLayout.h:475
const DataLayout & getDataLayout() const
void * getPointerToGlobalIfAvailable(StringRef S)
getPointerToGlobalIfAvailable - This returns the address of the specified global value if it is has a...
void addAtExitHandler(Function *F)
Definition: Interpreter.h:179
void exitCalled(GenericValue GV)
Definition: Execution.cpp:875
GenericValue callExternalFunction(Function *F, ArrayRef< GenericValue > ArgVals)
void resize(size_type N)
Definition: SmallVector.h:642
pointer data()
Return a pointer to the vector's buffer, even if empty().
Definition: SmallVector.h:289
This is a 'vector' (really, a variable-sized array), optimized for the case when the array is small.
Definition: SmallVector.h:1200
The instances of the Type class are immutable: once they are created, they are never changed.
Definition: Type.h:45
@ FunctionTyID
Functions.
Definition: Type.h:72
@ ArrayTyID
Arrays.
Definition: Type.h:75
@ VoidTyID
type with no size
Definition: Type.h:63
@ FloatTyID
32-bit floating point type
Definition: Type.h:58
@ StructTyID
Structures.
Definition: Type.h:74
@ IntegerTyID
Arbitrary bit width integers.
Definition: Type.h:71
@ DoubleTyID
64-bit floating point type
Definition: Type.h:59
@ PointerTyID
Pointers.
Definition: Type.h:73
TypeID getTypeID() const
Return the type id for the type.
Definition: Type.h:137
static void * SearchForAddressOfSymbol(const char *symbolName)
This function will search through all previously loaded dynamic libraries for the symbol symbolName.
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
SmartScopedLock< false > ScopedLock
Definition: Mutex.h:71
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
raw_fd_ostream & outs()
This returns a reference to a raw_fd_ostream for standard output.
void append_range(Container &C, Range &&R)
Wrapper function to append a range to a container.
Definition: STLExtras.h:2014
GenericValue PTOGV(void *P)
Definition: GenericValue.h:49
void report_fatal_error(Error Err, bool gen_crash_diag=true)
Report a serious error, calling any installed error handler.
Definition: Error.cpp:145
raw_fd_ostream & errs()
This returns a reference to a raw_ostream for standard error.
void * GVTOP(const GenericValue &GV)
Definition: GenericValue.h:50