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//===-- ClangDocMain.cpp - ClangDoc -----------------------------*- C++ -*-===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// This tool for generating C and C++ documentation from source code
// and comments. Generally, it runs a LibTooling FrontendAction on source files,
// mapping each declaration in those files to its USR and serializing relevant
// information into LLVM bitcode. It then runs a pass over the collected
// declaration information, reducing by USR. There is an option to dump this
// intermediate result to bitcode. Finally, it hands the reduced information
// off to a generator, which does the final parsing from the intermediate
// representation to the desired output format.
#include "BitcodeReader.h"
#include "BitcodeWriter.h"
#include "ClangDoc.h"
#include "Generators.h"
#include "Representation.h"
#include "clang/AST/AST.h"
#include "clang/AST/Decl.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
#include "clang/ASTMatchers/ASTMatchersInternal.h"
#include "clang/Driver/Options.h"
#include "clang/Frontend/FrontendActions.h"
#include "clang/Tooling/AllTUsExecution.h"
#include "clang/Tooling/CommonOptionsParser.h"
#include "clang/Tooling/Execution.h"
#include "clang/Tooling/Tooling.h"
#include "llvm/ADT/APFloat.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Mutex.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/Process.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/ThreadPool.h"
#include "llvm/Support/raw_ostream.h"
#include <atomic>
#include <mutex>
#include <string>
using namespace clang::ast_matchers;
using namespace clang::tooling;
using namespace clang;
static llvm::cl::extrahelp CommonHelp(CommonOptionsParser::HelpMessage);
static llvm::cl::OptionCategory ClangDocCategory("clang-doc options");
static llvm::cl::opt<std::string>
ProjectName("project-name", llvm::cl::desc("Name of project."),
static llvm::cl::opt<bool> IgnoreMappingFailures(
llvm::cl::desc("Continue if files are not mapped correctly."),
llvm::cl::init(true), llvm::cl::cat(ClangDocCategory));
static llvm::cl::opt<std::string>
llvm::cl::desc("Directory for outputting generated files."),
llvm::cl::init("docs"), llvm::cl::cat(ClangDocCategory));
static llvm::cl::opt<bool>
PublicOnly("public", llvm::cl::desc("Document only public declarations."),
llvm::cl::init(false), llvm::cl::cat(ClangDocCategory));
static llvm::cl::opt<bool> DoxygenOnly(
llvm::cl::desc("Use only doxygen-style comments to generate docs."),
llvm::cl::init(false), llvm::cl::cat(ClangDocCategory));
static llvm::cl::list<std::string> UserStylesheets(
"stylesheets", llvm::cl::CommaSeparated,
llvm::cl::desc("CSS stylesheets to extend the default styles."),
static llvm::cl::opt<std::string> SourceRoot("source-root", llvm::cl::desc(R"(
Directory where processed files are stored.
Links to definition locations will only be
generated if the file is in this dir.)"),
static llvm::cl::opt<std::string>
RepositoryUrl("repository", llvm::cl::desc(R"(
URL of repository that hosts code.
Used for links to definition locations.)"),
enum OutputFormatTy {
static llvm::cl::opt<OutputFormatTy>
FormatEnum("format", llvm::cl::desc("Format for outputted docs."),
llvm::cl::values(clEnumValN(OutputFormatTy::yaml, "yaml",
"Documentation in YAML format."),
clEnumValN(OutputFormatTy::md, "md",
"Documentation in MD format."),
clEnumValN(OutputFormatTy::html, "html",
"Documentation in HTML format.")),
std::string getFormatString() {
switch (FormatEnum) {
case OutputFormatTy::yaml:
return "yaml";
case OutputFormatTy::md:
return "md";
case OutputFormatTy::html:
return "html";
llvm_unreachable("Unknown OutputFormatTy");
// This function isn't referenced outside its translation unit, but it
// can't use the "static" keyword because its address is used for
// GetMainExecutable (since some platforms don't support taking the
// address of main, and some platforms can't implement GetMainExecutable
// without being given the address of a function in the main executable).
std::string GetExecutablePath(const char *Argv0, void *MainAddr) {
return llvm::sys::fs::getMainExecutable(Argv0, MainAddr);
int main(int argc, const char **argv) {
std::error_code OK;
const char *Overview =
R"(Generates documentation from source code and comments.
Example usage for files without flags (default):
$ clang-doc File1.cpp File2.cpp ... FileN.cpp
Example usage for a project using a compile commands database:
$ clang-doc --executor=all-TUs compile_commands.json
auto Executor = clang::tooling::createExecutorFromCommandLineArgs(
argc, argv, ClangDocCategory, Overview);
if (!Executor) {
llvm::errs() << toString(Executor.takeError()) << "\n";
return 1;
// Fail early if an invalid format was provided.
std::string Format = getFormatString();
llvm::outs() << "Emiting docs in " << Format << " format.\n";
auto G = doc::findGeneratorByName(Format);
if (!G) {
llvm::errs() << toString(G.takeError()) << "\n";
return 1;
ArgumentsAdjuster ArgAdjuster;
if (!DoxygenOnly)
ArgAdjuster = combineAdjusters(
clang::doc::ClangDocContext CDCtx = {
{UserStylesheets.begin(), UserStylesheets.end()},
{"index.js", "index_json.js"}};
if (Format == "html") {
void *MainAddr = (void *)(intptr_t)GetExecutablePath;
std::string ClangDocPath = GetExecutablePath(argv[0], MainAddr);
llvm::SmallString<128> NativeClangDocPath;
llvm::sys::path::native(ClangDocPath, NativeClangDocPath);
llvm::SmallString<128> AssetsPath;
AssetsPath = llvm::sys::path::parent_path(NativeClangDocPath);
llvm::sys::path::append(AssetsPath, "..", "share", "clang");
llvm::SmallString<128> DefaultStylesheet;
llvm::sys::path::native(AssetsPath, DefaultStylesheet);
llvm::SmallString<128> IndexJS;
llvm::sys::path::native(AssetsPath, IndexJS);
llvm::sys::path::append(IndexJS, "index.js");
// Mapping phase
llvm::outs() << "Mapping decls...\n";
auto Err =
Executor->get()->execute(doc::newMapperActionFactory(CDCtx), ArgAdjuster);
if (Err) {
if (IgnoreMappingFailures)
llvm::errs() << "Error mapping decls in files. Clang-doc will ignore "
"these files and continue:\n"
<< toString(std::move(Err)) << "\n";
else {
llvm::errs() << toString(std::move(Err)) << "\n";
return 1;
// Collect values into output by key.
// In ToolResults, the Key is the hashed USR and the value is the
// bitcode-encoded representation of the Info object.
llvm::outs() << "Collecting infos...\n";
llvm::StringMap<std::vector<StringRef>> USRToBitcode;
[&](StringRef Key, StringRef Value) {
auto R = USRToBitcode.try_emplace(Key, std::vector<StringRef>());
// Collects all Infos according to their unique USR value. This map is added
// to from the thread pool below and is protected by the USRToInfoMutex.
llvm::sys::Mutex USRToInfoMutex;
llvm::StringMap<std::unique_ptr<doc::Info>> USRToInfo;
// First reducing phase (reduce all decls into one info per decl).
llvm::outs() << "Reducing " << USRToBitcode.size() << " infos...\n";
std::atomic<bool> Error;
Error = false;
llvm::sys::Mutex IndexMutex;
// ExecutorConcurrency is a flag exposed by AllTUsExecution.h
llvm::ThreadPool Pool(llvm::hardware_concurrency(ExecutorConcurrency));
for (auto &Group : USRToBitcode) {
Pool.async([&]() {
std::vector<std::unique_ptr<doc::Info>> Infos;
for (auto &Bitcode : Group.getValue()) {
llvm::BitstreamCursor Stream(Bitcode);
doc::ClangDocBitcodeReader Reader(Stream);
auto ReadInfos = Reader.readBitcode();
if (!ReadInfos) {
llvm::errs() << toString(ReadInfos.takeError()) << "\n";
Error = true;
std::move(ReadInfos->begin(), ReadInfos->end(),
auto Reduced = doc::mergeInfos(Infos);
if (!Reduced) {
llvm::errs() << llvm::toString(Reduced.takeError());
// Add a reference to this Info in the Index
std::lock_guard<llvm::sys::Mutex> Guard(IndexMutex);
clang::doc::Generator::addInfoToIndex(CDCtx.Idx, Reduced.get().get());
// Save in the result map (needs a lock due to threaded access).
std::lock_guard<llvm::sys::Mutex> Guard(USRToInfoMutex);
USRToInfo[Group.getKey()] = std::move(Reduced.get());
if (Error)
return 1;
// Ensure the root output directory exists.
if (std::error_code Err = llvm::sys::fs::create_directories(OutDirectory);
Err != std::error_code()) {
llvm::errs() << "Failed to create directory '" << OutDirectory << "'\n";
return 1;
// Run the generator.
llvm::outs() << "Generating docs...\n";
if (auto Err =
G->get()->generateDocs(OutDirectory, std::move(USRToInfo), CDCtx)) {
llvm::errs() << toString(std::move(Err)) << "\n";
return 1;
llvm::outs() << "Generating assets for docs...\n";
Err = G->get()->createResources(CDCtx);
if (Err) {
llvm::errs() << toString(std::move(Err)) << "\n";
return 1;
return 0;