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llvm-6502/lib/ExecutionEngine/Interpreter/ExternalFunctions.cpp
Nick Lewycky 93f70fc291 Link against libffi if available, fall back to "no external calls from 
interpreter mode" when it's not.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@68937 91177308-0d34-0410-b5e6-96231b3b80d8
2009-04-13 04:26:06 +00:00

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//===-- ExternalFunctions.cpp - Implement External Functions --------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains both code to deal with invoking "external" functions, but
// also contains code that implements "exported" external functions.
//
// There are currently two mechanisms for handling external functions in the
// Interpreter. The first is to implement lle_* wrapper functions that are
// specific to well-known library functions which manually translate the
// arguments from GenericValues and make the call. If such a wrapper does
// not exist, and libffi is available, then the Interpreter will attempt to
// invoke the function using libffi, after finding its address.
//
//===----------------------------------------------------------------------===//
#include "Interpreter.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/Config/config.h" // Detect libffi
#include "llvm/Support/Streams.h"
#include "llvm/System/DynamicLibrary.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Support/ManagedStatic.h"
#include <csignal>
#include <cstdio>
#include <map>
#include <cmath>
#include <cstring>
#ifdef HAVE_FFI_CALL
#ifdef HAVE_FFI_H
#include <ffi.h>
#define USE_LIBFFI
#elif HAVE_FFI_FFI_H
#include <ffi/ffi.h>
#define USE_LIBFFI
#endif
#endif
using namespace llvm;
typedef GenericValue (*ExFunc)(const FunctionType *,
const std::vector<GenericValue> &);
static ManagedStatic<std::map<const Function *, ExFunc> > ExportedFunctions;
static std::map<std::string, ExFunc> FuncNames;
#ifdef USE_LIBFFI
typedef void (*RawFunc)(void);
static ManagedStatic<std::map<const Function *, RawFunc> > RawFunctions;
#endif
static Interpreter *TheInterpreter;
static char getTypeID(const Type *Ty) {
switch (Ty->getTypeID()) {
case Type::VoidTyID: return 'V';
case Type::IntegerTyID:
switch (cast<IntegerType>(Ty)->getBitWidth()) {
case 1: return 'o';
case 8: return 'B';
case 16: return 'S';
case 32: return 'I';
case 64: return 'L';
default: return 'N';
}
case Type::FloatTyID: return 'F';
case Type::DoubleTyID: return 'D';
case Type::PointerTyID: return 'P';
case Type::FunctionTyID:return 'M';
case Type::StructTyID: return 'T';
case Type::ArrayTyID: return 'A';
case Type::OpaqueTyID: return 'O';
default: return 'U';
}
}
// Try to find address of external function given a Function object.
// Please note, that interpreter doesn't know how to assemble a
// real call in general case (this is JIT job), that's why it assumes,
// that all external functions has the same (and pretty "general") signature.
// The typical example of such functions are "lle_X_" ones.
static ExFunc lookupFunction(const Function *F) {
// Function not found, look it up... start by figuring out what the
// composite function name should be.
std::string ExtName = "lle_";
const FunctionType *FT = F->getFunctionType();
for (unsigned i = 0, e = FT->getNumContainedTypes(); i != e; ++i)
ExtName += getTypeID(FT->getContainedType(i));
ExtName += "_" + F->getName();
ExFunc FnPtr = FuncNames[ExtName];
if (FnPtr == 0)
FnPtr = FuncNames["lle_X_"+F->getName()];
if (FnPtr == 0) // Try calling a generic function... if it exists...
FnPtr = (ExFunc)(intptr_t)sys::DynamicLibrary::SearchForAddressOfSymbol(
("lle_X_"+F->getName()).c_str());
if (FnPtr != 0)
ExportedFunctions->insert(std::make_pair(F, FnPtr)); // Cache for later
return FnPtr;
}
#ifdef USE_LIBFFI
static ffi_type *ffiTypeFor(const Type *Ty) {
switch (Ty->getTypeID()) {
case Type::VoidTyID: return &ffi_type_void;
case Type::IntegerTyID:
switch (cast<IntegerType>(Ty)->getBitWidth()) {
case 8: return &ffi_type_sint8;
case 16: return &ffi_type_sint16;
case 32: return &ffi_type_sint32;
case 64: return &ffi_type_sint64;
}
case Type::FloatTyID: return &ffi_type_float;
case Type::DoubleTyID: return &ffi_type_double;
case Type::PointerTyID: return &ffi_type_pointer;
default: break;
}
// TODO: Support other types such as StructTyID, ArrayTyID, OpaqueTyID, etc.
cerr << "Type could not be mapped for use with libffi.\n";
abort();
return NULL;
}
static void *ffiValueFor(const Type *Ty, const GenericValue &AV,
void *ArgDataPtr) {
switch (Ty->getTypeID()) {
case Type::IntegerTyID:
switch (cast<IntegerType>(Ty)->getBitWidth()) {
case 8: {
int8_t *I8Ptr = (int8_t *) ArgDataPtr;
*I8Ptr = (int8_t) AV.IntVal.getZExtValue();
return ArgDataPtr;
}
case 16: {
int16_t *I16Ptr = (int16_t *) ArgDataPtr;
*I16Ptr = (int16_t) AV.IntVal.getZExtValue();
return ArgDataPtr;
}
case 32: {
int32_t *I32Ptr = (int32_t *) ArgDataPtr;
*I32Ptr = (int32_t) AV.IntVal.getZExtValue();
return ArgDataPtr;
}
case 64: {
int64_t *I64Ptr = (int64_t *) ArgDataPtr;
*I64Ptr = (int64_t) AV.IntVal.getZExtValue();
return ArgDataPtr;
}
}
case Type::FloatTyID: {
float *FloatPtr = (float *) ArgDataPtr;
*FloatPtr = AV.DoubleVal;
return ArgDataPtr;
}
case Type::DoubleTyID: {
double *DoublePtr = (double *) ArgDataPtr;
*DoublePtr = AV.DoubleVal;
return ArgDataPtr;
}
case Type::PointerTyID: {
void **PtrPtr = (void **) ArgDataPtr;
*PtrPtr = GVTOP(AV);
return ArgDataPtr;
}
default: break;
}
// TODO: Support other types such as StructTyID, ArrayTyID, OpaqueTyID, etc.
cerr << "Type value could not be mapped for use with libffi.\n";
abort();
return NULL;
}
static bool ffiInvoke(RawFunc Fn, Function *F,
const std::vector<GenericValue> &ArgVals,
const TargetData *TD, GenericValue &Result) {
ffi_cif cif;
const FunctionType *FTy = F->getFunctionType();
const unsigned NumArgs = F->arg_size();
// TODO: We don't have type information about the remaining arguments, because
// this information is never passed into ExecutionEngine::runFunction().
if (ArgVals.size() > NumArgs && F->isVarArg()) {
cerr << "Calling external var arg function '" << F->getName()
<< "' is not supported by the Interpreter.\n";
abort();
}
unsigned ArgBytes = 0;
std::vector<ffi_type*> args(NumArgs);
for (Function::const_arg_iterator A = F->arg_begin(), E = F->arg_end();
A != E; ++A) {
const unsigned ArgNo = A->getArgNo();
const Type *ArgTy = FTy->getParamType(ArgNo);
args[ArgNo] = ffiTypeFor(ArgTy);
ArgBytes += TD->getTypeStoreSize(ArgTy);
}
uint8_t *ArgData = (uint8_t*) alloca(ArgBytes);
uint8_t *ArgDataPtr = ArgData;
std::vector<void*> values(NumArgs);
for (Function::const_arg_iterator A = F->arg_begin(), E = F->arg_end();
A != E; ++A) {
const unsigned ArgNo = A->getArgNo();
const Type *ArgTy = FTy->getParamType(ArgNo);
values[ArgNo] = ffiValueFor(ArgTy, ArgVals[ArgNo], ArgDataPtr);
ArgDataPtr += TD->getTypeStoreSize(ArgTy);
}
const Type *RetTy = FTy->getReturnType();
ffi_type *rtype = ffiTypeFor(RetTy);
if (ffi_prep_cif(&cif, FFI_DEFAULT_ABI, NumArgs, rtype, &args[0]) == FFI_OK) {
void *ret = NULL;
if (RetTy->getTypeID() != Type::VoidTyID)
ret = alloca(TD->getTypeStoreSize(RetTy));
ffi_call(&cif, Fn, ret, &values[0]);
switch (RetTy->getTypeID()) {
case Type::IntegerTyID:
switch (cast<IntegerType>(RetTy)->getBitWidth()) {
case 8: Result.IntVal = APInt(8 , *(int8_t *) ret); break;
case 16: Result.IntVal = APInt(16, *(int16_t*) ret); break;
case 32: Result.IntVal = APInt(32, *(int32_t*) ret); break;
case 64: Result.IntVal = APInt(64, *(int64_t*) ret); break;
}
break;
case Type::FloatTyID: Result.FloatVal = *(float *) ret; break;
case Type::DoubleTyID: Result.DoubleVal = *(double*) ret; break;
case Type::PointerTyID: Result.PointerVal = *(void **) ret; break;
default: break;
}
return true;
}
return false;
}
#endif // USE_LIBFFI
GenericValue Interpreter::callExternalFunction(Function *F,
const std::vector<GenericValue> &ArgVals) {
TheInterpreter = this;
// Do a lookup to see if the function is in our cache... this should just be a
// deferred annotation!
std::map<const Function *, ExFunc>::iterator FI = ExportedFunctions->find(F);
if (ExFunc Fn = (FI == ExportedFunctions->end()) ? lookupFunction(F)
: FI->second)
return Fn(F->getFunctionType(), ArgVals);
#ifdef USE_LIBFFI
std::map<const Function *, RawFunc>::iterator RF = RawFunctions->find(F);
RawFunc RawFn;
if (RF == RawFunctions->end()) {
RawFn = (RawFunc)(intptr_t)
sys::DynamicLibrary::SearchForAddressOfSymbol(F->getName());
if (RawFn != 0)
RawFunctions->insert(std::make_pair(F, RawFn)); // Cache for later
} else {
RawFn = RF->second;
}
GenericValue Result;
if (RawFn != 0 && ffiInvoke(RawFn, F, ArgVals, getTargetData(), Result))
return Result;
#endif // USE_LIBFFI
cerr << "Tried to execute an unknown external function: "
<< F->getType()->getDescription() << " " << F->getName() << "\n";
if (F->getName() != "__main")
abort();
return GenericValue();
}
//===----------------------------------------------------------------------===//
// Functions "exported" to the running application...
//
extern "C" { // Don't add C++ manglings to llvm mangling :)
// void atexit(Function*)
GenericValue lle_X_atexit(const FunctionType *FT,
const std::vector<GenericValue> &Args) {
assert(Args.size() == 1);
TheInterpreter->addAtExitHandler((Function*)GVTOP(Args[0]));
GenericValue GV;
GV.IntVal = 0;
return GV;
}
// void exit(int)
GenericValue lle_X_exit(const FunctionType *FT,
const std::vector<GenericValue> &Args) {
TheInterpreter->exitCalled(Args[0]);
return GenericValue();
}
// void abort(void)
GenericValue lle_X_abort(const FunctionType *FT,
const std::vector<GenericValue> &Args) {
raise (SIGABRT);
return GenericValue();
}
// int sprintf(char *, const char *, ...) - a very rough implementation to make
// output useful.
GenericValue lle_X_sprintf(const FunctionType *FT,
const std::vector<GenericValue> &Args) {
char *OutputBuffer = (char *)GVTOP(Args[0]);
const char *FmtStr = (const char *)GVTOP(Args[1]);
unsigned ArgNo = 2;
// printf should return # chars printed. This is completely incorrect, but
// close enough for now.
GenericValue GV;
GV.IntVal = APInt(32, strlen(FmtStr));
while (1) {
switch (*FmtStr) {
case 0: return GV; // Null terminator...
default: // Normal nonspecial character
sprintf(OutputBuffer++, "%c", *FmtStr++);
break;
case '\\': { // Handle escape codes
sprintf(OutputBuffer, "%c%c", *FmtStr, *(FmtStr+1));
FmtStr += 2; OutputBuffer += 2;
break;
}
case '%': { // Handle format specifiers
char FmtBuf[100] = "", Buffer[1000] = "";
char *FB = FmtBuf;
*FB++ = *FmtStr++;
char Last = *FB++ = *FmtStr++;
unsigned HowLong = 0;
while (Last != 'c' && Last != 'd' && Last != 'i' && Last != 'u' &&
Last != 'o' && Last != 'x' && Last != 'X' && Last != 'e' &&
Last != 'E' && Last != 'g' && Last != 'G' && Last != 'f' &&
Last != 'p' && Last != 's' && Last != '%') {
if (Last == 'l' || Last == 'L') HowLong++; // Keep track of l's
Last = *FB++ = *FmtStr++;
}
*FB = 0;
switch (Last) {
case '%':
strcpy(Buffer, "%"); break;
case 'c':
sprintf(Buffer, FmtBuf, uint32_t(Args[ArgNo++].IntVal.getZExtValue()));
break;
case 'd': case 'i':
case 'u': case 'o':
case 'x': case 'X':
if (HowLong >= 1) {
if (HowLong == 1 &&
TheInterpreter->getTargetData()->getPointerSizeInBits() == 64 &&
sizeof(long) < sizeof(int64_t)) {
// Make sure we use %lld with a 64 bit argument because we might be
// compiling LLI on a 32 bit compiler.
unsigned Size = strlen(FmtBuf);
FmtBuf[Size] = FmtBuf[Size-1];
FmtBuf[Size+1] = 0;
FmtBuf[Size-1] = 'l';
}
sprintf(Buffer, FmtBuf, Args[ArgNo++].IntVal.getZExtValue());
} else
sprintf(Buffer, FmtBuf,uint32_t(Args[ArgNo++].IntVal.getZExtValue()));
break;
case 'e': case 'E': case 'g': case 'G': case 'f':
sprintf(Buffer, FmtBuf, Args[ArgNo++].DoubleVal); break;
case 'p':
sprintf(Buffer, FmtBuf, (void*)GVTOP(Args[ArgNo++])); break;
case 's':
sprintf(Buffer, FmtBuf, (char*)GVTOP(Args[ArgNo++])); break;
default: cerr << "<unknown printf code '" << *FmtStr << "'!>";
ArgNo++; break;
}
strcpy(OutputBuffer, Buffer);
OutputBuffer += strlen(Buffer);
}
break;
}
}
return GV;
}
// int printf(const char *, ...) - a very rough implementation to make output
// useful.
GenericValue lle_X_printf(const FunctionType *FT,
const std::vector<GenericValue> &Args) {
char Buffer[10000];
std::vector<GenericValue> NewArgs;
NewArgs.push_back(PTOGV((void*)&Buffer[0]));
NewArgs.insert(NewArgs.end(), Args.begin(), Args.end());
GenericValue GV = lle_X_sprintf(FT, NewArgs);
cout << Buffer;
return GV;
}
static void ByteswapSCANFResults(const char *Fmt, void *Arg0, void *Arg1,
void *Arg2, void *Arg3, void *Arg4, void *Arg5,
void *Arg6, void *Arg7, void *Arg8) {
void *Args[] = { Arg0, Arg1, Arg2, Arg3, Arg4, Arg5, Arg6, Arg7, Arg8, 0 };
// Loop over the format string, munging read values as appropriate (performs
// byteswaps as necessary).
unsigned ArgNo = 0;
while (*Fmt) {
if (*Fmt++ == '%') {
// Read any flag characters that may be present...
bool Suppress = false;
bool Half = false;
bool Long = false;
bool LongLong = false; // long long or long double
while (1) {
switch (*Fmt++) {
case '*': Suppress = true; break;
case 'a': /*Allocate = true;*/ break; // We don't need to track this
case 'h': Half = true; break;
case 'l': Long = true; break;
case 'q':
case 'L': LongLong = true; break;
default:
if (Fmt[-1] > '9' || Fmt[-1] < '0') // Ignore field width specs
goto Out;
}
}
Out:
// Read the conversion character
if (!Suppress && Fmt[-1] != '%') { // Nothing to do?
unsigned Size = 0;
const Type *Ty = 0;
switch (Fmt[-1]) {
case 'i': case 'o': case 'u': case 'x': case 'X': case 'n': case 'p':
case 'd':
if (Long || LongLong) {
Size = 8; Ty = Type::Int64Ty;
} else if (Half) {
Size = 4; Ty = Type::Int16Ty;
} else {
Size = 4; Ty = Type::Int32Ty;
}
break;
case 'e': case 'g': case 'E':
case 'f':
if (Long || LongLong) {
Size = 8; Ty = Type::DoubleTy;
} else {
Size = 4; Ty = Type::FloatTy;
}
break;
case 's': case 'c': case '[': // No byteswap needed
Size = 1;
Ty = Type::Int8Ty;
break;
default: break;
}
if (Size) {
GenericValue GV;
void *Arg = Args[ArgNo++];
memcpy(&GV, Arg, Size);
TheInterpreter->StoreValueToMemory(GV, (GenericValue*)Arg, Ty);
}
}
}
}
}
// int sscanf(const char *format, ...);
GenericValue lle_X_sscanf(const FunctionType *FT,
const std::vector<GenericValue> &args) {
assert(args.size() < 10 && "Only handle up to 10 args to sscanf right now!");
char *Args[10];
for (unsigned i = 0; i < args.size(); ++i)
Args[i] = (char*)GVTOP(args[i]);
GenericValue GV;
GV.IntVal = APInt(32, sscanf(Args[0], Args[1], Args[2], Args[3], Args[4],
Args[5], Args[6], Args[7], Args[8], Args[9]));
ByteswapSCANFResults(Args[1], Args[2], Args[3], Args[4],
Args[5], Args[6], Args[7], Args[8], Args[9], 0);
return GV;
}
// int scanf(const char *format, ...);
GenericValue lle_X_scanf(const FunctionType *FT,
const std::vector<GenericValue> &args) {
assert(args.size() < 10 && "Only handle up to 10 args to scanf right now!");
char *Args[10];
for (unsigned i = 0; i < args.size(); ++i)
Args[i] = (char*)GVTOP(args[i]);
GenericValue GV;
GV.IntVal = APInt(32, scanf( Args[0], Args[1], Args[2], Args[3], Args[4],
Args[5], Args[6], Args[7], Args[8], Args[9]));
ByteswapSCANFResults(Args[0], Args[1], Args[2], Args[3], Args[4],
Args[5], Args[6], Args[7], Args[8], Args[9]);
return GV;
}
// int fprintf(FILE *, const char *, ...) - a very rough implementation to make
// output useful.
GenericValue lle_X_fprintf(const FunctionType *FT,
const std::vector<GenericValue> &Args) {
assert(Args.size() >= 2);
char Buffer[10000];
std::vector<GenericValue> NewArgs;
NewArgs.push_back(PTOGV(Buffer));
NewArgs.insert(NewArgs.end(), Args.begin()+1, Args.end());
GenericValue GV = lle_X_sprintf(FT, NewArgs);
fputs(Buffer, (FILE *) GVTOP(Args[0]));
return GV;
}
} // End extern "C"
void Interpreter::initializeExternalFunctions() {
FuncNames["lle_X_atexit"] = lle_X_atexit;
FuncNames["lle_X_exit"] = lle_X_exit;
FuncNames["lle_X_abort"] = lle_X_abort;
FuncNames["lle_X_printf"] = lle_X_printf;
FuncNames["lle_X_sprintf"] = lle_X_sprintf;
FuncNames["lle_X_sscanf"] = lle_X_sscanf;
FuncNames["lle_X_scanf"] = lle_X_scanf;
FuncNames["lle_X_fprintf"] = lle_X_fprintf;
}
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