[clang-tidy][NFC] Do more work at compile time

[localspook]

  for (std::string OptionName : {
#define GET_CHECKER_OPTIONS
#define CHECKER_OPTION(TYPE, CHECKER, OPTION_NAME, DESCRIPTION, DEFAULT,       \
                       RELEASE, HIDDEN)                                        \
  Twine(AnalyzerCheckNamePrefix).concat(CHECKER ":" OPTION_NAME).str(),

#include "clang/StaticAnalyzer/Checkers/Checkers.inc"
#undef CHECKER_OPTION
#undef GET_CHECKER_OPTIONS
       }) {
    Result.Options.insert(OptionName);
  }

This code is doing a lot of unnecessary work at runtime. For each of the (currently) 59 checker options, it runs Twine(AnalyzerCheckNamePrefix).concat(CHECKER ":" OPTION_NAME).str(),, which allocates a string (all of this is unrolled, leading to code bloat). Then it copies all those strings (because std::string OptionName, not const std::string& OptionName). All of this can be done at compile time!

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[llvmbot]

@llvm/pr-subscribers-clang-tools-extra

@llvm/pr-subscribers-clang-tidy

Author: Victor Chernyakin (localspook)

Changes

  for (std::string OptionName : {
#define GET_CHECKER_OPTIONS
#define CHECKER_OPTION(TYPE, CHECKER, OPTION_NAME, DESCRIPTION, DEFAULT,       \
                       RELEASE, HIDDEN)                                        \
  Twine(AnalyzerCheckNamePrefix).concat(CHECKER ":" OPTION_NAME).str(),

#include "clang/StaticAnalyzer/Checkers/Checkers.inc"
#undef CHECKER_OPTION
#undef GET_CHECKER_OPTIONS
       }) {
    Result.Options.insert(OptionName);
  }

This code is doing a lot of unnecessary work at runtime. For each of the (currently) 59 checker options, it runs Twine(AnalyzerCheckNamePrefix).concat(CHECKER ":" OPTION_NAME).str(),, which allocates a string (all of this is unrolled, leading to code bloat). Then it copies all those strings (because std::string OptionName, not const std::string& OptionName). All of this can be done at compile time!

---

Full diff: https://github.com/llvm/llvm-project/pull/147406.diff

1 Files Affected:

• (modified) clang-tools-extra/clang-tidy/ClangTidy.cpp (+6-5)

diff --git a/clang-tools-extra/clang-tidy/ClangTidy.cpp b/clang-tools-extra/clang-tidy/ClangTidy.cpp
index f4ab93b51f4a7..815033c2e5175 100644
--- a/clang-tools-extra/clang-tidy/ClangTidy.cpp
+++ b/clang-tools-extra/clang-tidy/ClangTidy.cpp
@@ -668,18 +668,19 @@ getAllChecksAndOptions(bool AllowEnablingAnalyzerAlphaCheckers) {
     Buffer.append(AnalyzerCheck);
     Result.Checks.insert(Buffer);
   }
-  for (std::string OptionName : {
+
+  static constexpr llvm::StringLiteral OptionNames[] = {
 #define GET_CHECKER_OPTIONS
 #define CHECKER_OPTION(TYPE, CHECKER, OPTION_NAME, DESCRIPTION, DEFAULT,       \
                        RELEASE, HIDDEN)                                        \
-  Twine(AnalyzerCheckNamePrefix).concat(CHECKER ":" OPTION_NAME).str(),
+  "clang-analyzer-" CHECKER ":" OPTION_NAME,
 
 #include "clang/StaticAnalyzer/Checkers/Checkers.inc"
 #undef CHECKER_OPTION
 #undef GET_CHECKER_OPTIONS
-       }) {
-    Result.Options.insert(OptionName);
-  }
+  };
+
+  Result.Options.insert_range(OptionNames);
 #endif // CLANG_TIDY_ENABLE_STATIC_ANALYZER
 
   Context.setOptionsCollector(&Result.Options);

[vbvictor]

Please make the title more detailed about what you changed exactly.

[PiotrZSL]

LGTM

[PiotrZSL]

AnalyzerCheckNamePrefix is not used it, change it into macro, in such case it could be "configured" properly.