blob: 65638dc88a60f0682ef2f6fa1d3e2125b86eeb95 [file] [log] [blame]
//===--- Check.cpp - clangd self-diagnostics ------------------------------===//
// 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
// Many basic problems can occur processing a file in clangd, e.g.:
// - system includes are not found
// - crash when indexing its AST
// clangd --check provides a simplified, isolated way to reproduce these,
// with no editor, LSP, threads, background indexing etc to contend with.
// One important use case is gathering information for bug reports.
// Another is reproducing crashes, and checking which setting prevent them.
// It simulates opening a file (determining compile command, parsing, indexing)
// and then running features at many locations.
// Currently it adds some basic logging of progress and results.
// We should consider extending it to also recognize common symptoms and
// recommend solutions (e.g. standard library installation issues).
#include "ClangdLSPServer.h"
#include "CodeComplete.h"
#include "Config.h"
#include "GlobalCompilationDatabase.h"
#include "Hover.h"
#include "ParsedAST.h"
#include "Preamble.h"
#include "SourceCode.h"
#include "XRefs.h"
#include "index/CanonicalIncludes.h"
#include "index/FileIndex.h"
#include "refactor/Tweak.h"
#include "support/ThreadsafeFS.h"
#include "support/Trace.h"
#include "clang/AST/ASTContext.h"
#include "clang/Basic/DiagnosticIDs.h"
#include "clang/Format/Format.h"
#include "clang/Frontend/CompilerInvocation.h"
#include "clang/Tooling/CompilationDatabase.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/Path.h"
namespace clang {
namespace clangd {
namespace {
// Print (and count) the error-level diagnostics (warnings are ignored).
unsigned showErrors(llvm::ArrayRef<Diag> Diags) {
unsigned ErrCount = 0;
for (const auto &D : Diags) {
if (D.Severity >= DiagnosticsEngine::Error) {
elog("[{0}] Line {1}: {2}", D.Name, D.Range.start.line + 1, D.Message);
return ErrCount;
// This class is just a linear pipeline whose functions get called in sequence.
// Each exercises part of clangd's logic on our test file and logs results.
// Later steps depend on state built in earlier ones (such as the AST).
// Many steps can fatally fail (return false), then subsequent ones cannot run.
// Nonfatal failures are logged and tracked in ErrCount.
class Checker {
// from constructor
std::string File;
ClangdLSPServer::Options Opts;
// from buildCommand
tooling::CompileCommand Cmd;
// from buildInvocation
ParseInputs Inputs;
std::unique_ptr<CompilerInvocation> Invocation;
format::FormatStyle Style;
// from buildAST
std::shared_ptr<const PreambleData> Preamble;
llvm::Optional<ParsedAST> AST;
FileIndex Index;
// Number of non-fatal errors seen.
unsigned ErrCount = 0;
Checker(llvm::StringRef File, const ClangdLSPServer::Options &Opts)
: File(File), Opts(Opts) {}
// Read compilation database and choose a compile command for the file.
bool buildCommand(const ThreadsafeFS &TFS) {
log("Loading compilation database...");
DirectoryBasedGlobalCompilationDatabase::Options CDBOpts(TFS);
CDBOpts.CompileCommandsDir =
std::unique_ptr<GlobalCompilationDatabase> BaseCDB =
BaseCDB = getQueryDriverDatabase(llvm::makeArrayRef(Opts.QueryDriverGlobs),
auto Mangler = CommandMangler::detect();
if (Opts.ResourceDir)
Mangler.ResourceDir = *Opts.ResourceDir;
auto CDB = std::make_unique<OverlayCDB>(
BaseCDB.get(), std::vector<std::string>{},
if (auto TrueCmd = CDB->getCompileCommand(File)) {
Cmd = std::move(*TrueCmd);
log("Compile command from CDB is: {0}", printArgv(Cmd.CommandLine));
} else {
Cmd = CDB->getFallbackCommand(File);
log("Generic fallback command is: {0}", printArgv(Cmd.CommandLine));
return true;
// Prepare inputs and build CompilerInvocation (parsed compile command).
bool buildInvocation(const ThreadsafeFS &TFS,
llvm::Optional<std::string> Contents) {
StoreDiags CaptureInvocationDiags;
std::vector<std::string> CC1Args;
Inputs.CompileCommand = Cmd;
Inputs.TFS = &TFS;
Inputs.ClangTidyProvider = Opts.ClangTidyProvider;
if (Contents.hasValue()) {
Inputs.Contents = *Contents;
log("Imaginary source file contents:\n{0}", Inputs.Contents);
} else {
if (auto Contents = TFS.view(llvm::None)->getBufferForFile(File)) {
Inputs.Contents = Contents->get()->getBuffer().str();
} else {
elog("Couldn't read {0}: {1}", File, Contents.getError().message());
return false;
log("Parsing command...");
Invocation =
buildCompilerInvocation(Inputs, CaptureInvocationDiags, &CC1Args);
auto InvocationDiags = CaptureInvocationDiags.take();
ErrCount += showErrors(InvocationDiags);
log("internal (cc1) args are: {0}", printArgv(CC1Args));
if (!Invocation) {
elog("Failed to parse command line");
return false;
// FIXME: Check that resource-dir/built-in-headers exist?
Style = getFormatStyleForFile(File, Inputs.Contents, TFS);
return true;
// Build preamble and AST, and index them.
bool buildAST() {
log("Building preamble...");
Preamble =
buildPreamble(File, *Invocation, Inputs, /*StoreInMemory=*/true,
[&](ASTContext &Ctx, std::shared_ptr<Preprocessor> PP,
const CanonicalIncludes &Includes) {
if (!Opts.BuildDynamicSymbolIndex)
log("Indexing headers...");
Index.updatePreamble(File, /*Version=*/"null", Ctx,
std::move(PP), Includes);
if (!Preamble) {
elog("Failed to build preamble");
return false;
ErrCount += showErrors(Preamble->Diags);
log("Building AST...");
AST = ParsedAST::build(File, Inputs, std::move(Invocation),
/*InvocationDiags=*/std::vector<Diag>{}, Preamble);
if (!AST) {
elog("Failed to build AST");
return false;
ErrCount += showErrors(llvm::makeArrayRef(*AST->getDiagnostics())
if (Opts.BuildDynamicSymbolIndex) {
log("Indexing AST...");
Index.updateMain(File, *AST);
return true;
// Run AST-based features at each token in the file.
void testLocationFeatures(
llvm::function_ref<bool(const Position &)> ShouldCheckLine,
const bool EnableCodeCompletion) {
trace::Span Trace("testLocationFeatures");
log("Testing features at each token (may be slow in large files)");
auto &SM = AST->getSourceManager();
auto SpelledTokens = AST->getTokens().spelledTokens(SM.getMainFileID());
CodeCompleteOptions CCOpts = Opts.CodeComplete;
CCOpts.Index = &Index;
for (const auto &Tok : SpelledTokens) {
unsigned Start = AST->getSourceManager().getFileOffset(Tok.location());
unsigned End = Start + Tok.length();
Position Pos = offsetToPosition(Inputs.Contents, Start);
if (!ShouldCheckLine(Pos))
trace::Span Trace("Token");
SPAN_ATTACH(Trace, "pos", Pos);
SPAN_ATTACH(Trace, "text", Tok.text(AST->getSourceManager()));
// FIXME: dumping the tokens may leak sensitive code into bug reports.
// Add an option to turn this off, once we decide how options work.
vlog(" {0} {1}", Pos, Tok.text(AST->getSourceManager()));
auto Tree = SelectionTree::createRight(AST->getASTContext(),
AST->getTokens(), Start, End);
Tweak::Selection Selection(&Index, *AST, Start, End, std::move(Tree),
// FS is only populated when applying a tweak, not during prepare as
// prepare should not do any I/O to be fast.
auto Tweaks =
prepareTweaks(Selection, Opts.TweakFilter, Opts.FeatureModules);
Selection.FS =
for (const auto &T : Tweaks) {
auto Result = T->apply(Selection);
if (!Result) {
elog(" tweak: {0} ==> FAIL: {1}", T->id(), Result.takeError());
} else {
vlog(" tweak: {0}", T->id());
unsigned Definitions = locateSymbolAt(*AST, Pos, &Index).size();
vlog(" definition: {0}", Definitions);
auto Hover = getHover(*AST, Pos, Style, &Index);
vlog(" hover: {0}", Hover.hasValue());
if (EnableCodeCompletion) {
Position EndPos = offsetToPosition(Inputs.Contents, End);
auto CC = codeComplete(File, EndPos, Preamble.get(), Inputs, CCOpts);
vlog(" code completion: {0}",
CC.Completions.empty() ? "<empty>" : CC.Completions[0].Name);
} // namespace
bool check(llvm::StringRef File,
llvm::function_ref<bool(const Position &)> ShouldCheckLine,
const ThreadsafeFS &TFS, const ClangdLSPServer::Options &Opts,
bool EnableCodeCompletion) {
llvm::SmallString<0> FakeFile;
llvm::Optional<std::string> Contents;
if (File.empty()) {
llvm::sys::path::system_temp_directory(false, FakeFile);
llvm::sys::path::append(FakeFile, "");
File = FakeFile;
Contents = R"cpp(
#include <stddef.h>
#include <string>
size_t N = 50;
auto xxx = std::string(N, 'x');
log("Testing on source file {0}", File);
auto ContextProvider = ClangdServer::createConfiguredContextProvider(
Opts.ConfigProvider, nullptr);
WithContext Ctx(ContextProvider(
? File
: /*Don't turn on local configs for an arbitrary temp path.*/ ""));
Checker C(File, Opts);
if (!C.buildCommand(TFS) || !C.buildInvocation(TFS, Contents) ||
return false;
C.testLocationFeatures(ShouldCheckLine, EnableCodeCompletion);
log("All checks completed, {0} errors", C.ErrCount);
return C.ErrCount == 0;
} // namespace clangd
} // namespace clang