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[clang-tidy] Speed up misc-header-include-cycle #148757

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[clang-tidy] Speed up misc-header-include-cycle #148757

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7cab196
[clang-tidy] Speed up `misc-header-include-cycle`
localspook Jul 13, 2025
477eef1
Add release notes, restore `EndOfMainFile` override
localspook Jul 15, 2025
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76 changes: 36 additions & 40 deletions clang-tools-extra/clang-tidy/misc/HeaderIncludeCycleCheck.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -13,8 +13,8 @@
#include "clang/Lex/Preprocessor.h"
#include "llvm/Support/Regex.h"
#include <algorithm>
#include <deque>
#include <optional>
#include <vector>

using namespace clang::ast_matchers;

Expand All @@ -23,8 +23,8 @@ namespace clang::tidy::misc {
namespace {

struct Include {
FileID Id;
llvm::StringRef Name;
const FileEntry *File;
StringRef Name;
SourceLocation Loc;
};

Expand All @@ -50,31 +50,27 @@ class CyclicDependencyCallbacks : public PPCallbacks {
if (Reason != EnterFile && Reason != ExitFile)
return;

FileID Id = SM.getFileID(Loc);
const FileID Id = SM.getFileID(Loc);
if (Id.isInvalid())
return;

const FileEntry *NewFile = SM.getFileEntryForID(Id);
const FileEntry *PrevFile = SM.getFileEntryForID(PrevFID);

if (Reason == ExitFile) {
if ((Files.size() > 1U) && (Files.back().Id == PrevFID) &&
(Files[Files.size() - 2U].Id == Id))
if ((Files.size() > 1U) && (Files.back().File == PrevFile) &&
(Files[Files.size() - 2U].File == NewFile))
Files.pop_back();
return;
}

if (!Files.empty() && Files.back().Id == Id)
if (!Files.empty() && Files.back().File == NewFile)
return;

std::optional<llvm::StringRef> FilePath = SM.getNonBuiltinFilenameForID(Id);
llvm::StringRef FileName =
FilePath ? llvm::sys::path::filename(*FilePath) : llvm::StringRef();

if (!NextToEnter)
NextToEnter = Include{Id, FileName, SourceLocation()};

assert(NextToEnter->Name == FileName);
NextToEnter->Id = Id;
Files.emplace_back(*NextToEnter);
NextToEnter.reset();
const std::optional<StringRef> FilePath = SM.getNonBuiltinFilenameForID(Id);
const StringRef FileName =
FilePath ? llvm::sys::path::filename(*FilePath) : StringRef();
Files.push_back({NewFile, FileName, std::exchange(NextToEnter, {})});
}

void InclusionDirective(SourceLocation, const Token &, StringRef FilePath,
Expand All @@ -85,36 +81,26 @@ class CyclicDependencyCallbacks : public PPCallbacks {
if (FileType != clang::SrcMgr::C_User)
return;

llvm::StringRef FileName = llvm::sys::path::filename(FilePath);
NextToEnter = {FileID(), FileName, Range.getBegin()};
NextToEnter = Range.getBegin();

if (!File)
return;

FileID Id = SM.translateFile(*File);
if (Id.isInvalid())
return;

checkForDoubleInclude(Id, FileName, Range.getBegin());
}

void EndOfMainFile() override {
if (!Files.empty() && Files.back().Id == SM.getMainFileID())
Files.pop_back();

assert(Files.empty());
checkForDoubleInclude(&File->getFileEntry(),
llvm::sys::path::filename(FilePath),
Range.getBegin());
}

void checkForDoubleInclude(FileID Id, llvm::StringRef FileName,
void checkForDoubleInclude(const FileEntry *File, StringRef FileName,
SourceLocation Loc) {
auto It =
std::find_if(Files.rbegin(), Files.rend(),
[&](const Include &Entry) { return Entry.Id == Id; });
const auto It =
llvm::find_if(llvm::reverse(Files),
[&](const Include &Entry) { return Entry.File == File; });
if (It == Files.rend())
return;

const std::optional<StringRef> FilePath = SM.getNonBuiltinFilenameForID(Id);
if (!FilePath || isFileIgnored(*FilePath))
const StringRef FilePath = File->tryGetRealPathName();
if (FilePath.empty() || isFileIgnored(FilePath))
return;

if (It == Files.rbegin()) {
Expand Down Expand Up @@ -144,9 +130,19 @@ class CyclicDependencyCallbacks : public PPCallbacks {
});
}

#ifndef NDEBUG
void EndOfMainFile() override {
if (!Files.empty() &&
Files.back().File == SM.getFileEntryForID(SM.getMainFileID()))
Files.pop_back();

assert(Files.empty());
}
#endif

private:
std::deque<Include> Files;
std::optional<Include> NextToEnter;
std::vector<Include> Files;
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Deque were used because there are situation when you can have 200 includes and to avoid re-allocation.
You could consider using llvm::SmallVector with some pre-allocation, to speed things up even more.

SourceLocation NextToEnter;
HeaderIncludeCycleCheck &Check;
const SourceManager &SM;
std::vector<llvm::Regex> IgnoredFilesRegexes;
Expand Down
3 changes: 3 additions & 0 deletions clang-tools-extra/docs/ReleaseNotes.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -257,6 +257,9 @@ Changes in existing checks
`AnalyzePointers` option and fixing false positives when using const array
type.

- Improved :doc:`misc-header-include-cycle
<clang-tidy/checks/misc/header-include-cycle>` check performance.

- Improved :doc:`misc-include-cleaner
<clang-tidy/checks/misc/include-cleaner>` check by adding the options
`UnusedIncludes` and `MissingIncludes`, which specify whether the check should
Expand Down