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//===- Interpreter.cpp - Top-Level LLVM Interpreter Implementation --------===//
//
// This file implements the top-level functionality for the LLVM interpreter.
// This interpreter is designed to be a very simple, portable, inefficient
// interpreter.
//
//===----------------------------------------------------------------------===//
#include "Interpreter.h"
#include "llvm/Module.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
/// create - Create a new interpreter object. This can never fail.
///
ExecutionEngine *Interpreter::create(Module *M, bool TraceMode){
bool isLittleEndian;
switch (M->getEndianness()) {
case Module::LittleEndian: isLittleEndian = true; break;
case Module::BigEndian: isLittleEndian = false; break;
case Module::AnyPointerSize:
int Test = 0;
*(char*)&Test = 1; // Return true if the host is little endian
isLittleEndian = (Test == 1);
break;
}
bool isLongPointer;
switch (M->getPointerSize()) {
case Module::Pointer32: isLongPointer = false; break;
case Module::Pointer64: isLongPointer = true; break;
case Module::AnyPointerSize:
isLongPointer = (sizeof(void*) == 8); // Follow host
break;
}
return new Interpreter(M, isLittleEndian, isLongPointer, TraceMode);
}
//===----------------------------------------------------------------------===//
// Interpreter ctor - Initialize stuff
//
Interpreter::Interpreter(Module *M, bool isLittleEndian, bool isLongPointer,
bool TraceMode)
: ExecutionEngine(M), ExitCode(0), Trace(TraceMode),
CurFrame(-1), TD("lli", isLittleEndian, isLongPointer ? 8 : 4,
isLongPointer ? 8 : 4, isLongPointer ? 8 : 4) {
setTargetData(TD);
// Initialize the "backend"
initializeExecutionEngine();
initializeExternalFunctions();
CW.setModule(M); // Update Writer
emitGlobals();
}
void Interpreter::runAtExitHandlers () {
while (!AtExitHandlers.empty()) {
callFunction(AtExitHandlers.back(), std::vector<GenericValue>());
AtExitHandlers.pop_back();
run();
}
}
/// run - Start execution with the specified function and arguments.
///
GenericValue Interpreter::run(Function *F,
const std::vector<GenericValue> &ArgValues) {
assert (F && "Function *F was null at entry to run()");
// Try extra hard not to pass extra args to a function that isn't
// expecting them. C programmers frequently bend the rules and
// declare main() with fewer parameters than it actually gets
// passed, and the interpreter barfs if you pass a function more
// parameters than it is declared to take. This does not attempt to
// take into account gratuitous differences in declared types,
// though.
std::vector<GenericValue> ActualArgs;
const unsigned ArgCount = F->getFunctionType()->getParamTypes().size();
for (unsigned i = 0; i < ArgCount; ++i) {
ActualArgs.push_back (ArgValues[i]);
}
// Set up the function call.
callFunction(F, ActualArgs);
// Reset the current frame location to the top of stack
CurFrame = ECStack.size()-1;
// Start executing the function.
run();
// Run any atexit handlers now!
runAtExitHandlers();
GenericValue rv;
rv.IntVal = ExitCode;
return rv;
}
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