[clang-tidy][NFC] Do less unnecessary work in modernize-deprecated-headers (llvm#160967)

- `IncludeModernizePPCallbacks` creates temporary vectors when all it needs is constant arrays - The header replacement strings are `std::string` when they can just be `StringRef` - `IncludeModernizePPCallbacks`'s constructor 1. Takes `LangOptions` by value (the thing is 832 bytes) 2. Stores it, but none of `IncludeModernizePPCallbacks`'s member functions use it

Author: localspook

clang-tools-extra/clang-tidy/modernize/DeprecatedHeadersCheck.cpp

@@ -24,8 +24,9 @@ namespace {
 class IncludeModernizePPCallbacks : public PPCallbacks {
 public:
  explicit IncludeModernizePPCallbacks(
- std::vector<IncludeMarker> &IncludesToBeProcessed, LangOptions LangOpts,
- const SourceManager &SM, bool CheckHeaderFile);
+ std::vector<IncludeMarker> &IncludesToBeProcessed,
+ const LangOptions &LangOpts, const SourceManager &SM,
+ bool CheckHeaderFile);
 
  void InclusionDirective(SourceLocation HashLoc, const Token &IncludeTok,
  StringRef FileName, bool IsAngled,
@@ -37,8 +38,7 @@ class IncludeModernizePPCallbacks : public PPCallbacks {
 
 private:
  std::vector<IncludeMarker> &IncludesToBeProcessed;
- LangOptions LangOpts;
- llvm::StringMap<std::string> CStyledHeaderToCxx;
+ llvm::StringMap<StringRef> CStyledHeaderToCxx;
  llvm::StringSet<> DeleteHeaders;
  const SourceManager &SM;
  bool CheckHeaderFile;
@@ -131,48 +131,35 @@ void DeprecatedHeadersCheck::check(
 }
 
 IncludeModernizePPCallbacks::IncludeModernizePPCallbacks(
- std::vector<IncludeMarker> &IncludesToBeProcessed, LangOptions LangOpts,
- const SourceManager &SM, bool CheckHeaderFile)
- : IncludesToBeProcessed(IncludesToBeProcessed), LangOpts(LangOpts), SM(SM),
+ std::vector<IncludeMarker> &IncludesToBeProcessed,
+ const LangOptions &LangOpts, const SourceManager &SM, bool CheckHeaderFile)
+ : IncludesToBeProcessed(IncludesToBeProcessed), SM(SM),
  CheckHeaderFile(CheckHeaderFile) {
- for (const auto &KeyValue :
- std::vector<std::pair<llvm::StringRef, std::string>>(
- {{"assert.h", "cassert"},
- {"complex.h", "complex"},
- {"ctype.h", "cctype"},
- {"errno.h", "cerrno"},
- {"float.h", "cfloat"},
- {"limits.h", "climits"},
- {"locale.h", "clocale"},
- {"math.h", "cmath"},
- {"setjmp.h", "csetjmp"},
- {"signal.h", "csignal"},
- {"stdarg.h", "cstdarg"},
- {"stddef.h", "cstddef"},
- {"stdio.h", "cstdio"},
- {"stdlib.h", "cstdlib"},
- {"string.h", "cstring"},
- {"time.h", "ctime"},
- {"wchar.h", "cwchar"},
- {"wctype.h", "cwctype"}})) {
- CStyledHeaderToCxx.insert(KeyValue);
- }
- // Add C++11 headers.
- if (LangOpts.CPlusPlus11) {
- for (const auto &KeyValue :
- std::vector<std::pair<llvm::StringRef, std::string>>(
- {{"fenv.h", "cfenv"},
- {"stdint.h", "cstdint"},
- {"inttypes.h", "cinttypes"},
- {"tgmath.h", "ctgmath"},
- {"uchar.h", "cuchar"}})) {
- CStyledHeaderToCxx.insert(KeyValue);
- }
- }
- for (const auto &Key :
- std::vector<std::string>({"stdalign.h", "stdbool.h", "iso646.h"})) {
- DeleteHeaders.insert(Key);
- }
+
+ static constexpr std::pair<StringRef, StringRef> CXX98Headers[] = {
+ {"assert.h", "cassert"}, {"complex.h", "complex"},
+ {"ctype.h", "cctype"}, {"errno.h", "cerrno"},
+ {"float.h", "cfloat"}, {"limits.h", "climits"},
+ {"locale.h", "clocale"}, {"math.h", "cmath"},
+ {"setjmp.h", "csetjmp"}, {"signal.h", "csignal"},
+ {"stdarg.h", "cstdarg"}, {"stddef.h", "cstddef"},
+ {"stdio.h", "cstdio"}, {"stdlib.h", "cstdlib"},
+ {"string.h", "cstring"}, {"time.h", "ctime"},
+ {"wchar.h", "cwchar"}, {"wctype.h", "cwctype"},
+ };
+ CStyledHeaderToCxx.insert(std::begin(CXX98Headers), std::end(CXX98Headers));
+
+ static constexpr std::pair<StringRef, StringRef> CXX11Headers[] = {
+ {"fenv.h", "cfenv"}, {"stdint.h", "cstdint"},
+ {"inttypes.h", "cinttypes"}, {"tgmath.h", "ctgmath"},
+ {"uchar.h", "cuchar"},
+ };
+ if (LangOpts.CPlusPlus11)
+ CStyledHeaderToCxx.insert(std::begin(CXX11Headers), std::end(CXX11Headers));
+
+ static constexpr StringRef HeadersToDelete[] = {"stdalign.h", "stdbool.h",
+ "iso646.h"};
+ DeleteHeaders.insert_range(HeadersToDelete);
 }
 
 void IncludeModernizePPCallbacks::InclusionDirective(
@@ -205,7 +192,7 @@ void IncludeModernizePPCallbacks::InclusionDirective(
  } else if (DeleteHeaders.contains(FileName)) {
  IncludesToBeProcessed.emplace_back(
  // NOLINTNEXTLINE(modernize-use-emplace) - false-positive
- IncludeMarker{std::string{}, FileName,
+ IncludeMarker{StringRef{}, FileName,
  SourceRange{HashLoc, FilenameRange.getEnd()}, DiagLoc});
  }
 }

clang-tools-extra/clang-tidy/modernize/DeprecatedHeadersCheck.h

@@ -44,7 +44,7 @@ class DeprecatedHeadersCheck : public ClangTidyCheck {
  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
 
  struct IncludeMarker {
- std::string Replacement;
+ StringRef Replacement;
  StringRef FileName;
  SourceRange ReplacementRange;
  SourceLocation DiagLoc;