1//===- Interpreter.cpp - Top-Level LLVM Interpreter Implementation --------===//
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 implements the top-level functionality for the LLVM interpreter.
10// This interpreter is designed to be a very simple, portable, inefficient
11// interpreter.
12//
13//===----------------------------------------------------------------------===//
14
15#include "Interpreter.h"
16#include "llvm/CodeGen/IntrinsicLowering.h"
17#include "llvm/IR/DerivedTypes.h"
18#include "llvm/IR/Module.h"
19#include <cstring>
20using namespace llvm;
21
22namespace {
23
24static struct RegisterInterp {
25 RegisterInterp() { Interpreter::Register(); }
26} InterpRegistrator;
27
28}
29
30extern "C" void LLVMLinkInInterpreter() { }
31
32/// Create a new interpreter object.
33///
34ExecutionEngine *Interpreter::create(std::unique_ptr<Module> M,
35 std::string *ErrStr) {
36 // Tell this Module to materialize everything and release the GVMaterializer.
37 if (Error Err = M->materializeAll()) {
38 std::string Msg;
39 handleAllErrors(E: std::move(Err), Handlers: [&](ErrorInfoBase &EIB) {
40 Msg = EIB.message();
41 });
42 if (ErrStr)
43 *ErrStr = Msg;
44 // We got an error, just return 0
45 return nullptr;
46 }
47
48 return new Interpreter(std::move(M));
49}
50
51//===----------------------------------------------------------------------===//
52// Interpreter ctor - Initialize stuff
53//
54Interpreter::Interpreter(std::unique_ptr<Module> M)
55 : ExecutionEngine(std::move(M)) {
56
57 memset(s: &ExitValue.Untyped, c: 0, n: sizeof(ExitValue.Untyped));
58 // Initialize the "backend"
59 initializeExecutionEngine();
60 initializeExternalFunctions();
61 emitGlobals();
62
63 IL = new IntrinsicLowering(getDataLayout());
64}
65
66Interpreter::~Interpreter() {
67 delete IL;
68}
69
70void Interpreter::runAtExitHandlers () {
71 while (!AtExitHandlers.empty()) {
72 callFunction(F: AtExitHandlers.back(), ArgVals: {});
73 AtExitHandlers.pop_back();
74 run();
75 }
76}
77
78/// run - Start execution with the specified function and arguments.
79///
80GenericValue Interpreter::runFunction(Function *F,
81 ArrayRef<GenericValue> ArgValues) {
82 assert (F && "Function *F was null at entry to run()");
83
84 // Try extra hard not to pass extra args to a function that isn't
85 // expecting them. C programmers frequently bend the rules and
86 // declare main() with fewer parameters than it actually gets
87 // passed, and the interpreter barfs if you pass a function more
88 // parameters than it is declared to take. This does not attempt to
89 // take into account gratuitous differences in declared types,
90 // though.
91 const size_t ArgCount = F->getFunctionType()->getNumParams();
92 ArrayRef<GenericValue> ActualArgs =
93 ArgValues.slice(N: 0, M: std::min(a: ArgValues.size(), b: ArgCount));
94
95 // Set up the function call.
96 callFunction(F, ArgVals: ActualArgs);
97
98 // Start executing the function.
99 run();
100
101 return ExitValue;
102}
103