//===-- FuzzerCLI.h - Common logic for CLIs of fuzzers ----------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License.  See LICENSE.TXT for details. 
//
//===----------------------------------------------------------------------===//
//
// Common logic needed to implement LLVM's fuzz targets' CLIs - including LLVM
// concepts like cl::opt and libFuzzer concepts like -ignore_remaining_args=1. 
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_FUZZMUTATE_FUZZER_CLI_H
#define LLVM_FUZZMUTATE_FUZZER_CLI_H

#include "llvm/ADT/StringRef.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/Support/DataTypes.h"

namespace llvm {

/// Parse cl::opts from a fuzz target commandline. 
///
/// This handles all arguments after -ignore_remaining_args=1 as cl::opts. 
void parseFuzzerCLOpts(int ArgC, char *ArgV[]);

/// Handle backend options that are encoded in the executable name. 
///
/// Parses some common backend options out of a specially crafted executable
/// name (argv[0]).  For example, a name like llvm-foo-fuzzer--aarch64-gisel
/// might set up an AArch64 triple and the Global ISel selector.  This should be
/// called *before* parseFuzzerCLOpts if calling both. 
///
/// This is meant to be used for environments like OSS-Fuzz that aren't capable
/// of passing in command line arguments in the normal way. 
void handleExecNameEncodedBEOpts(StringRef ExecName);

/// Handle optimizer options which are encoded in the executable name. 
/// Same semantics as in 'handleExecNameEncodedBEOpts'. 
void handleExecNameEncodedOptimizerOpts(StringRef ExecName);

using FuzzerTestFun = int (*)(const uint8_t *Data, size_t Size);
using FuzzerInitFun = int (*)(int *argc, char ***argv);

/// Runs a fuzz target on the inputs specified on the command line. 
///
/// Useful for testing fuzz targets without linking to libFuzzer.  Finds inputs
/// in the argument list in a libFuzzer compatible way. 
int runFuzzerOnInputs(int ArgC, char *ArgV[], FuzzerTestFun TestOne,
                      FuzzerInitFun Init = [](int *, char ***) { return 0; });

/// Fuzzer friendly interface for the llvm bitcode parser. 
///
/// \param Data Bitcode we are going to parse
/// \param Size Size of the 'Data' in bytes
/// \return New module or nullptr in case of error
std::unique_ptr<Module> parseModule(const uint8_t *Data, size_t Size,
                                    LLVMContext &Context);

/// Fuzzer friendly interface for the llvm bitcode printer. 
///
/// \param M Module to print
/// \param Dest Location to store serialized module
/// \param MaxSize Size of the destination buffer
/// \return Number of bytes that were written.  When module size exceeds MaxSize
///         returns 0 and leaves Dest unchanged. 
size_t writeModule(const Module &M, uint8_t *Dest, size_t MaxSize);

/// Try to parse module and verify it.  May output verification errors to the
/// errs(). 
/// \return New module or nullptr in case of error. 
std::unique_ptr<Module> parseAndVerify(const uint8_t *Data, size_t Size,
                                       LLVMContext &Context);

} // end llvm namespace

#endif // LLVM_FUZZMUTATE_FUZZER_CLI_H
