Author: David Zbarsky Date: 2026-07-08T07:27:10-07:00 New Revision: 974fc1319640cce76523bcee48d003421ec7c163
URL: https://github.com/llvm/llvm-project/commit/974fc1319640cce76523bcee48d003421ec7c163 DIFF: https://github.com/llvm/llvm-project/commit/974fc1319640cce76523bcee48d003421ec7c163.diff LOG: [clang][Frontend] Table-drive compiler option dumping (#203161) `Features.def` currently expands 228 feature formatting expressions and 49 extension formatting expressions in `DumpCompilerOptionsAction::ExecuteAction`. This stores the names in NUL-separated character blobs, evaluates the predicates into local `bool` arrays, and formats both arrays with `writeCompilerOptionValues`. In a Release arm64 build, standalone clang decreases by 49,256 bytes unstripped and 49,520 bytes stripped, while the LLVM multicall binary decreases by 49,264 bytes unstripped and 49,528 bytes stripped; linked `__text` decreases by 52,696 bytes and linked fixups decrease by 7. Work towards #202616 AI tool disclosure: Co-authored with OpenAI Codex. Added: Modified: clang/lib/Frontend/FrontendActions.cpp clang/test/Frontend/compiler-options-dump.cpp Removed: ################################################################################ diff --git a/clang/lib/Frontend/FrontendActions.cpp b/clang/lib/Frontend/FrontendActions.cpp index f3fce25b78a8c..5edf76133f7ef 100644 --- a/clang/lib/Frontend/FrontendActions.cpp +++ b/clang/lib/Frontend/FrontendActions.cpp @@ -1166,6 +1166,23 @@ void PrintPreambleAction::ExecuteAction() { } } +static void writeCompilerOptionValues(raw_ostream &OS, + StringRef CompilerOptionNames, + ArrayRef<bool> CompilerOptionValues) { + bool FirstValue = true; + for (bool CompilerOptionValue : CompilerOptionValues) { + auto [CompilerOptionName, RemainingCompilerOptionNames] = + CompilerOptionNames.split('\0'); + CompilerOptionNames = RemainingCompilerOptionNames; + if (!FirstValue) + OS << ",\n"; + FirstValue = false; + OS << "\t{\"" << CompilerOptionName + << "\" : " << (CompilerOptionValue ? "true" : "false") << "}"; + } + assert(CompilerOptionNames.empty() && "compiler option name count mismatch"); +} + void DumpCompilerOptionsAction::ExecuteAction() { CompilerInstance &CI = getCompilerInstance(); std::unique_ptr<raw_ostream> OSP = @@ -1185,29 +1202,32 @@ void DumpCompilerOptionsAction::ExecuteAction() { OS << "{\n"; OS << "\n\"features\" : [\n"; { - llvm::SmallString<128> Str; -#define FEATURE(Name, Predicate) \ - ("\t{\"" #Name "\" : " + llvm::Twine(Predicate ? "true" : "false") + "},\n") \ - .toVector(Str); + static constexpr char FeatureNames[] = { +#define FEATURE(Name, Predicate) #Name "\0" +#include "clang/Basic/Features.def" + }; + const bool FeatureValues[] = { +#define FEATURE(Name, Predicate) static_cast<bool>(Predicate), #include "clang/Basic/Features.def" -#undef FEATURE - // Remove the newline and comma from the last entry to ensure this remains - // valid JSON. - OS << Str.substr(0, Str.size() - 2); + }; + writeCompilerOptionValues( + OS, StringRef(FeatureNames, sizeof(FeatureNames) - 1), FeatureValues); } OS << "\n],\n"; OS << "\n\"extensions\" : [\n"; { - llvm::SmallString<128> Str; -#define EXTENSION(Name, Predicate) \ - ("\t{\"" #Name "\" : " + llvm::Twine(Predicate ? "true" : "false") + "},\n") \ - .toVector(Str); + static constexpr char ExtensionNames[] = { +#define EXTENSION(Name, Predicate) #Name "\0" +#include "clang/Basic/Features.def" + }; + const bool ExtensionValues[] = { +#define EXTENSION(Name, Predicate) static_cast<bool>(Predicate), #include "clang/Basic/Features.def" -#undef EXTENSION - // Remove the newline and comma from the last entry to ensure this remains - // valid JSON. - OS << Str.substr(0, Str.size() - 2); + }; + writeCompilerOptionValues( + OS, StringRef(ExtensionNames, sizeof(ExtensionNames) - 1), + ExtensionValues); } OS << "\n]\n"; diff --git a/clang/test/Frontend/compiler-options-dump.cpp b/clang/test/Frontend/compiler-options-dump.cpp index daa8bb18549a4..5cd45670b5aed 100644 --- a/clang/test/Frontend/compiler-options-dump.cpp +++ b/clang/test/Frontend/compiler-options-dump.cpp @@ -1,6 +1,7 @@ // RUN: %clang_cc1 -compiler-options-dump -std=c++03 %s -o - | FileCheck %s --check-prefix=CXX03 // RUN: %clang_cc1 -compiler-options-dump -std=c++17 %s -o - | FileCheck %s --check-prefix=CXX17 // RUN: %clang_cc1 -compiler-options-dump -std=c99 -x c %s -o - | FileCheck %s --check-prefix=C99 +// RUN: %clang_cc1 -compiler-options-dump -std=c++17 %s -o - | %python -c 'import json, sys; json.load(sys.stdin)' // CXX03: "features" // CXX03: "cxx_auto_type" : false _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
