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// Copyright 2021 The Tint Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "fuzzers/tint_ast_fuzzer/cli.h"
#include <cstring>
#include <iostream>
#include <limits>
#include <sstream>
#include <string>
#include <utility>
namespace tint {
namespace fuzzers {
namespace ast_fuzzer {
namespace {
const char* const kHelpMessage = R"(
This is a fuzzer for the Tint compiler that works by mutating the AST.
Below is a list of all supported parameters for this fuzzer. You may want to
run it with -help=1 to check out libfuzzer parameters.
-tint_enable_all_mutations=
If `false`, the fuzzer will only apply mutations from a
randomly selected subset of mutation types. Otherwise,
all mutation types will be considered. This must be one
of `true` or `false` (without `). By default it's `false`.
-tint_fuzzing_target=
Specifies the shading language to target during fuzzing.
This must be one or a combination of `wgsl`, `spv`, `hlsl`,
`msl` (without `) separated by commas. By default it's
`wgsl,msl,hlsl,spv`.
-tint_help
Show this message. Note that there is also a -help=1
parameter that will display libfuzzer's help message.
-tint_mutation_batch_size=
The number of mutations to apply in a single libfuzzer
mutation session. This must be a numeric value that fits
in type `uint32_t`. By default it's 5.
)";
bool HasPrefix(const char* str, const char* prefix) {
return strncmp(str, prefix, strlen(prefix)) == 0;
}
[[noreturn]] void InvalidParam(const char* param) {
std::cout << "Invalid value for " << param << std::endl;
std::cout << kHelpMessage << std::endl;
exit(1);
}
bool ParseBool(const char* value, bool* out) {
if (!strcmp(value, "true")) {
*out = true;
} else if (!strcmp(value, "false")) {
*out = false;
} else {
return false;
}
return true;
}
bool ParseUint32(const char* value, uint32_t* out) {
auto parsed = strtoul(value, nullptr, 10);
if (parsed > std::numeric_limits<uint32_t>::max()) {
return false;
}
*out = static_cast<uint32_t>(parsed);
return true;
}
bool ParseFuzzingTarget(const char* value, FuzzingTarget* out) {
if (!strcmp(value, "wgsl")) {
*out = FuzzingTarget::kWgsl;
} else if (!strcmp(value, "spv")) {
*out = FuzzingTarget::kSpv;
} else if (!strcmp(value, "msl")) {
*out = FuzzingTarget::kMsl;
} else if (!strcmp(value, "hlsl")) {
*out = FuzzingTarget::kHlsl;
} else {
return false;
}
return true;
}
} // namespace
CliParams ParseCliParams(int* argc, char** argv) {
CliParams cli_params;
auto help = false;
for (int i = *argc - 1; i > 0; --i) {
auto param = argv[i];
auto recognized_parameter = true;
if (HasPrefix(param, "-tint_enable_all_mutations=")) {
if (!ParseBool(param + sizeof("-tint_enable_all_mutations=") - 1,
&cli_params.enable_all_mutations)) {
InvalidParam(param);
}
} else if (HasPrefix(param, "-tint_mutation_batch_size=")) {
if (!ParseUint32(param + sizeof("-tint_mutation_batch_size=") - 1,
&cli_params.mutation_batch_size)) {
InvalidParam(param);
}
} else if (HasPrefix(param, "-tint_fuzzing_target=")) {
auto result = FuzzingTarget::kNone;
std::stringstream ss(param + sizeof("-tint_fuzzing_target=") - 1);
for (std::string value; std::getline(ss, value, ',');) {
auto tmp = FuzzingTarget::kNone;
if (!ParseFuzzingTarget(value.c_str(), &tmp)) {
InvalidParam(param);
}
result = result | tmp;
}
if (result == FuzzingTarget::kNone) {
InvalidParam(param);
}
cli_params.fuzzing_target = result;
} else if (!strcmp(param, "-tint_help")) {
help = true;
} else {
recognized_parameter = false;
}
if (recognized_parameter) {
// Remove the recognized parameter from the list of all parameters by
// swapping it with the last one. This will suppress warnings in the
// libFuzzer about unrecognized parameters. By default, libFuzzer thinks
// that all user-defined parameters start with two dashes. However, we are
// forced to use a single one to make the fuzzer compatible with the
// ClusterFuzz.
std::swap(argv[i], argv[*argc - 1]);
*argc -= 1;
}
}
if (help) {
std::cout << kHelpMessage << std::endl;
exit(0);
}
return cli_params;
}
} // namespace ast_fuzzer
} // namespace fuzzers
} // namespace tint