// Copyright 2020 The SwiftShader Authors. All Rights Reserved.
//
// 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.

// turbo-cov is a minimal re-implementation of LLVM's llvm-cov, that emits just
// the per segment coverage in a binary stream. This avoids the overhead of
// encoding to JSON.

#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ProfileData/Coverage/CoverageMapping.h"
#include "llvm/ProfileData/InstrProfReader.h"

#include <cstdio>

using namespace llvm;
using namespace coverage;

namespace {

template<typename T>
void emit(T v)
{
	fwrite(&v, sizeof(v), 1, stdout);
}

void emit(const llvm::StringRef &str)
{
	uint64_t len = str.size();
	emit<uint32_t>(len);
	fwrite(str.data(), len, 1, stdout);
}

}  // namespace

int main(int argc, const char **argv)
{
	if(argc < 3)
	{
		fprintf(stderr, "turbo-cov <exe> <profdata>\n");
		return 1;
	}

	auto exe = argv[1];
	auto profdata = argv[2];

	auto res = CoverageMapping::load({ exe }, profdata);
	if(Error E = res.takeError())
	{
		fprintf(stderr, "Failed to load executable '%s': %s\n", exe, toString(std::move(E)).c_str());
		return 1;
	}

	auto coverage = std::move(res.get());
	if(!coverage)
	{
		fprintf(stderr, "Could not load coverage information\n");
		return 1;
	}

	if(auto mismatched = coverage->getMismatchedCount())
	{
		fprintf(stderr, "%d functions have mismatched data\n", (int)mismatched);
		return 1;
	}

	// uint32 num_files
	//   file[0]
	//     uint32 filename.length
	//     <data> filename.data
	//     uint32 num_segments
	//       file[0].segment[0]
	//         uint32 line
	//         uint32 col
	//         uint32 count
	//         uint8  hasCount
	//       file[0].segment[1]
	//         ...
	//   file[2]
	//     ...

	auto files = coverage->getUniqueSourceFiles();
	emit<uint32_t>(files.size());
	for(auto &file : files)
	{
		emit(file);
		auto fileCoverage = coverage->getCoverageForFile(file);
		emit<uint32_t>(fileCoverage.end() - fileCoverage.begin());
		for(auto &segment : fileCoverage)
		{
			emit<uint32_t>(segment.Line);
			emit<uint32_t>(segment.Col);
			emit<uint32_t>(segment.Count);
			emit<uint8_t>(segment.HasCount ? 1 : 0);
		}
	}

	return 0;
}