Author: Naveen Seth Hanig Date: 2025-12-17T22:18:02+05:30 New Revision: fbe5e8c9f482df2f527b8f81f22c61a4c487c2ca
URL: https://github.com/llvm/llvm-project/commit/fbe5e8c9f482df2f527b8f81f22c61a4c487c2ca DIFF: https://github.com/llvm/llvm-project/commit/fbe5e8c9f482df2f527b8f81f22c61a4c487c2ca.diff LOG: Revert "Revert "Reland [clang][modules-driver] Add scanner to detect C++20 module presence (#153497)"" (#172693) Reverts llvm/llvm-project#172655 This causes a linkage issue. Added: clang/test/Driver/modules-driver-cxx20-module-usage-scanner.cpp Modified: clang/include/clang/Basic/DiagnosticDriverKinds.td clang/include/clang/Basic/DiagnosticGroups.td clang/include/clang/Driver/Driver.h clang/include/clang/Lex/DependencyDirectivesScanner.h clang/include/clang/Options/Options.td clang/lib/Driver/CMakeLists.txt clang/lib/Driver/Driver.cpp clang/lib/Lex/DependencyDirectivesScanner.cpp Removed: ################################################################################ diff --git a/clang/include/clang/Basic/DiagnosticDriverKinds.td b/clang/include/clang/Basic/DiagnosticDriverKinds.td index a4061b594d968..fca84904326c9 100644 --- a/clang/include/clang/Basic/DiagnosticDriverKinds.td +++ b/clang/include/clang/Basic/DiagnosticDriverKinds.td @@ -599,6 +599,13 @@ def err_drv_reduced_module_output_overrided : Warning< "please consider use '-fmodule-output=' to specify the output file for reduced BMI explicitly">, InGroup<DiagGroup<"reduced-bmi-output-overrided">>; +def remark_found_cxx20_module_usage : Remark< + "found C++20 module usage in file '%0'">, + InGroup<ModulesDriver>; +def remark_performing_driver_managed_module_build : Remark< + "performing driver managed module build">, + InGroup<ModulesDriver>; + def warn_drv_delayed_template_parsing_after_cxx20 : Warning< "-fdelayed-template-parsing is deprecated after C++20">, InGroup<DiagGroup<"delayed-template-parsing-in-cxx20">>; diff --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td index 86332f7748324..e1dba0195f470 100644 --- a/clang/include/clang/Basic/DiagnosticGroups.td +++ b/clang/include/clang/Basic/DiagnosticGroups.td @@ -640,6 +640,7 @@ def ModuleConflict : DiagGroup<"module-conflict">; def ModuleFileExtension : DiagGroup<"module-file-extension">; def ModuleIncludeDirectiveTranslation : DiagGroup<"module-include-translation">; def ModuleMap : DiagGroup<"module-map">; +def ModulesDriver : DiagGroup<"modules-driver">; def RoundTripCC1Args : DiagGroup<"round-trip-cc1-args">; def NewlineEOF : DiagGroup<"newline-eof">; def Nullability : DiagGroup<"nullability">; diff --git a/clang/include/clang/Driver/Driver.h b/clang/include/clang/Driver/Driver.h index b7bd1bc8aab49..76a6c5a128efb 100644 --- a/clang/include/clang/Driver/Driver.h +++ b/clang/include/clang/Driver/Driver.h @@ -507,6 +507,9 @@ class Driver { /// BuildActions - Construct the list of actions to perform for the /// given arguments, which are only done for a single architecture. + /// If the compilation is an explicit module build, delegates to + /// BuildDriverManagedModuleBuildActions. Otherwise, BuildDefaultActions is + /// used. /// /// \param C - The compilation that is being built. /// \param Args - The input arguments. @@ -791,6 +794,35 @@ class Driver { /// compilation based on which -f(no-)?lto(=.*)? option occurs last. void setLTOMode(const llvm::opt::ArgList &Args); + /// BuildDefaultActions - Constructs the list of actions to perform + /// for the provided arguments, which are only done for a single architecture. + /// + /// \param C - The compilation that is being built. + /// \param Args - The input arguments. + /// \param Actions - The list to store the resulting actions onto. + void BuildDefaultActions(Compilation &C, llvm::opt::DerivedArgList &Args, + const InputList &Inputs, ActionList &Actions) const; + + /// BuildDriverManagedModuleBuildActions - Performs a dependency + /// scan and constructs the list of actions to perform for dependency order + /// and the provided arguments. This is only done for a single a architecture. + /// + /// \param C - The compilation that is being built. + /// \param Args - The input arguments. + /// \param Actions - The list to store the resulting actions onto. + void BuildDriverManagedModuleBuildActions(Compilation &C, + llvm::opt::DerivedArgList &Args, + const InputList &Inputs, + ActionList &Actions) const; + + /// Scans the leading lines of the C++ source inputs to detect C++20 module + /// usage. + /// + /// \returns True if module usage is detected, false otherwise, or an error on + /// read failure. + llvm::ErrorOr<bool> + ScanInputsForCXX20ModulesUsage(const InputList &Inputs) const; + /// Retrieves a ToolChain for a particular \p Target triple. /// /// Will cache ToolChains for the life of the driver object, and create them diff --git a/clang/include/clang/Lex/DependencyDirectivesScanner.h b/clang/include/clang/Lex/DependencyDirectivesScanner.h index f9fec3998ca53..c0b742d652a03 100644 --- a/clang/include/clang/Lex/DependencyDirectivesScanner.h +++ b/clang/include/clang/Lex/DependencyDirectivesScanner.h @@ -135,6 +135,13 @@ void printDependencyDirectivesAsSource( ArrayRef<dependency_directives_scan::Directive> Directives, llvm::raw_ostream &OS); +/// Scan an input source buffer for C++20 named module usage. +/// +/// \param Source The input source buffer. +/// +/// \returns true if any C++20 named modules related directive was found. +bool scanInputForCXX20ModulesUsage(StringRef Source); + /// Functor that returns the dependency directives for a given file. class DependencyDirectivesGetter { public: diff --git a/clang/include/clang/Options/Options.td b/clang/include/clang/Options/Options.td index 8cd31a3be109a..c7caad8da1fd3 100644 --- a/clang/include/clang/Options/Options.td +++ b/clang/include/clang/Options/Options.td @@ -3410,6 +3410,13 @@ defm modules_reduced_bmi : BoolOption<"f", "modules-reduced-bmi", PosFlag<SetTrue, [], [ClangOption, CC1Option], "Generate the reduced BMI">>; +def fmodules_driver : Flag<["-"], "fmodules-driver">, + Group<f_Group>, Visibility<[ClangOption]>, + HelpText<"Enable support for driver managed module builds (experimental)">; +def fno_modules_driver : Flag<["-"], "fno-modules-driver">, + Group<f_Group>, Visibility<[ClangOption]>, + HelpText<"Disable support for driver managed module builds (experimental)">; + def experimental_modules_reduced_bmi : Flag<["-"], "fexperimental-modules-reduced-bmi">, Group<f_Group>, Visibility<[ClangOption, CC1Option]>, Alias<fmodules_reduced_bmi>; diff --git a/clang/lib/Driver/CMakeLists.txt b/clang/lib/Driver/CMakeLists.txt index 997649178bb21..0026ba8991719 100644 --- a/clang/lib/Driver/CMakeLists.txt +++ b/clang/lib/Driver/CMakeLists.txt @@ -100,6 +100,8 @@ add_clang_library(clangDriver LINK_LIBS clangBasic clangFrontend + clangSerialization + clangLex clangOptions ${system_libs} ) diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp index 6a2ee1794b7d7..e63d5397d469b 100644 --- a/clang/lib/Driver/Driver.cpp +++ b/clang/lib/Driver/Driver.cpp @@ -66,6 +66,7 @@ #include "clang/Driver/Tool.h" #include "clang/Driver/ToolChain.h" #include "clang/Driver/Types.h" +#include "clang/Lex/DependencyDirectivesScanner.h" #include "clang/Options/OptionUtils.h" #include "clang/Options/Options.h" #include "llvm/ADT/ArrayRef.h" @@ -4221,6 +4222,11 @@ void Driver::handleArguments(Compilation &C, DerivedArgList &Args, YcArg = nullptr; } + if (Args.hasArgNoClaim(options::OPT_fmodules_driver)) + // TODO: Check against all incompatible -fmodules-driver arguments + if (!ModulesModeCXX20 && !Args.hasArgNoClaim(options::OPT_fmodules)) + Args.eraseArg(options::OPT_fmodules_driver); + Arg *FinalPhaseArg; phases::ID FinalPhase = getFinalPhase(Args, &FinalPhaseArg); @@ -4347,6 +4353,33 @@ void Driver::handleArguments(Compilation &C, DerivedArgList &Args, } } +static bool hasCXXModuleInputType(const Driver::InputList &Inputs) { + const auto IsTypeCXXModule = [](const auto &Input) -> bool { + const auto TypeID = Input.first; + return (TypeID == types::TY_CXXModule); + }; + return llvm::any_of(Inputs, IsTypeCXXModule); +} + +llvm::ErrorOr<bool> +Driver::ScanInputsForCXX20ModulesUsage(const InputList &Inputs) const { + const auto CXXInputs = llvm::make_filter_range( + Inputs, [](const auto &Input) { return types::isCXX(Input.first); }); + for (const auto &Input : CXXInputs) { + StringRef Filename = Input.second->getSpelling(); + auto ErrOrBuffer = VFS->getBufferForFile(Filename); + if (!ErrOrBuffer) + return ErrOrBuffer.getError(); + const auto Buffer = std::move(*ErrOrBuffer); + + if (scanInputForCXX20ModulesUsage(Buffer->getBuffer())) { + Diags.Report(diag::remark_found_cxx20_module_usage) << Filename; + return true; + } + } + return false; +} + void Driver::BuildActions(Compilation &C, DerivedArgList &Args, const InputList &Inputs, ActionList &Actions) const { llvm::PrettyStackTraceString CrashInfo("Building compilation actions"); @@ -4358,6 +4391,33 @@ void Driver::BuildActions(Compilation &C, DerivedArgList &Args, handleArguments(C, Args, Inputs, Actions); + if (Args.hasFlag(options::OPT_fmodules_driver, + options::OPT_fno_modules_driver, false)) { + // TODO: Move the logic for implicitly enabling explicit-module-builds out + // of -fmodules-driver once it is no longer experimental. + // Currently, this serves diagnostic purposes only. + bool UsesCXXModules = hasCXXModuleInputType(Inputs); + if (!UsesCXXModules) { + const auto ErrOrScanResult = ScanInputsForCXX20ModulesUsage(Inputs); + if (!ErrOrScanResult) { + Diags.Report(diag::err_cannot_open_file) + << ErrOrScanResult.getError().message(); + return; + } + UsesCXXModules = *ErrOrScanResult; + } + if (UsesCXXModules || Args.hasArg(options::OPT_fmodules)) + BuildDriverManagedModuleBuildActions(C, Args, Inputs, Actions); + return; + } + + BuildDefaultActions(C, Args, Inputs, Actions); +} + +void Driver::BuildDefaultActions(Compilation &C, DerivedArgList &Args, + const InputList &Inputs, + ActionList &Actions) const { + bool UseNewOffloadingDriver = C.isOffloadingHostKind(Action::OFK_OpenMP) || C.isOffloadingHostKind(Action::OFK_SYCL) || @@ -4649,6 +4709,12 @@ void Driver::BuildActions(Compilation &C, DerivedArgList &Args, Args.ClaimAllArgs(options::OPT_cl_ignored_Group); } +void Driver::BuildDriverManagedModuleBuildActions( + Compilation &C, llvm::opt::DerivedArgList &Args, const InputList &Inputs, + ActionList &Actions) const { + Diags.Report(diag::remark_performing_driver_managed_module_build); +} + /// Returns the canonical name for the offloading architecture when using a HIP /// or CUDA architecture. static StringRef getCanonicalArchString(Compilation &C, diff --git a/clang/lib/Lex/DependencyDirectivesScanner.cpp b/clang/lib/Lex/DependencyDirectivesScanner.cpp index 9ccff5e3342d5..eee57c786442a 100644 --- a/clang/lib/Lex/DependencyDirectivesScanner.cpp +++ b/clang/lib/Lex/DependencyDirectivesScanner.cpp @@ -83,6 +83,8 @@ struct Scanner { /// \returns True on error. bool scan(SmallVectorImpl<Directive> &Directives); + friend bool clang::scanInputForCXX20ModulesUsage(StringRef Source); + private: /// Lexes next token and advances \p First and the \p Lexer. [[nodiscard]] dependency_directives_scan::Token & @@ -1075,3 +1077,51 @@ void clang::printDependencyDirectivesAsSource( } } } + +static void skipUntilMaybeCXX20ModuleDirective(const char *&First, + const char *const End) { + assert(First <= End); + while (First != End) { + if (*First == '#') { + ++First; + skipToNewlineRaw(First, End); + } + skipWhitespace(First, End); + if (const auto Len = isEOL(First, End)) { + First += Len; + continue; + } + break; + } +} + +bool clang::scanInputForCXX20ModulesUsage(StringRef Source) { + const char *First = Source.begin(); + const char *const End = Source.end(); + skipUntilMaybeCXX20ModuleDirective(First, End); + if (First == End) + return false; + + // Check if the next token can even be a module directive before creating a + // full lexer. + if (!(*First == 'i' || *First == 'e' || *First == 'm')) + return false; + + llvm::SmallVector<dependency_directives_scan::Token> Tokens; + Scanner S(StringRef(First, End - First), Tokens, nullptr, SourceLocation()); + S.TheLexer.setParsingPreprocessorDirective(true); + if (S.lexModule(First, End)) + return false; + auto IsCXXNamedModuleDirective = [](const DirectiveWithTokens &D) { + switch (D.Kind) { + case dependency_directives_scan::cxx_module_decl: + case dependency_directives_scan::cxx_import_decl: + case dependency_directives_scan::cxx_export_module_decl: + case dependency_directives_scan::cxx_export_import_decl: + return true; + default: + return false; + } + }; + return llvm::any_of(S.DirsWithToks, IsCXXNamedModuleDirective); +} diff --git a/clang/test/Driver/modules-driver-cxx20-module-usage-scanner.cpp b/clang/test/Driver/modules-driver-cxx20-module-usage-scanner.cpp new file mode 100644 index 0000000000000..a434587a78759 --- /dev/null +++ b/clang/test/Driver/modules-driver-cxx20-module-usage-scanner.cpp @@ -0,0 +1,192 @@ +// The driver never checks to implicitly enable the explicit module build +// support unless at least two input files are provided. +// To trigger the C++20 module usage check, we always pass a second dummy file +// as input. +// TODO: Remove -fmodules everywhere once implicitly enabled explicit module +// builds are supported. + +// RUN: split-file %s %t +//--- empty.cpp +// Nothing here + +//--- only-global.cpp +// RUN: %clang -std=c++20 -ccc-print-phases -fmodules-driver -Rmodules-driver \ +// RUN: %t/only-global.cpp %t/empty.cpp 2>&1 \ +// RUN: | FileCheck %s --check-prefix=CHECK1 +// CHECK1: remark: found C++20 module usage in file '{{.*}}' [-Rmodules-driver] +module; + +//--- only-import.cpp +// RUN: %clang -std=c++20 -ccc-print-phases -fmodules-driver -Rmodules-driver \ +// RUN: %t/only-import.cpp %t/empty.cpp 2>&1 \ +// RUN: | FileCheck %s --check-prefix=CHECK2 +// CHECK2: remark: found C++20 module usage in file '{{.*}}' [-Rmodules-driver] +import A; + +//--- only-export.cpp +// RUN: %clang -std=c++20 -ccc-print-phases -fmodules-driver -Rmodules-driver \ +// RUN: %t/only-export.cpp %t/empty.cpp 2>&1 \ +// RUN: | FileCheck %s --check-prefix=CHECK3 +// CHECK3: remark: found C++20 module usage in file '{{.*}}' [-Rmodules-driver] +export module A; + +//--- leading-line-comment.cpp +// RUN: %clang -std=c++20 -ccc-print-phases -fmodules-driver -Rmodules-driver \ +// RUN: %t/leading-line-comment.cpp %t/empty.cpp 2>&1 \ +// RUN: | FileCheck %s --check-prefix=CHECK4 +// CHECK4: remark: found C++20 module usage in file '{{.*}}' [-Rmodules-driver] +// My line comment +import A; + +//--- leading-block-comment1.cpp +// RUN: %clang -std=c++20 -ccc-print-phases -fmodules-driver -Rmodules-driver \ +// RUN: %t/leading-block-comment1.cpp %t/empty.cpp 2>&1 \ +// RUN: | FileCheck %s --check-prefix=CHECK5 +// CHECK5: remark: found C++20 module usage in file '{{.*}}' [-Rmodules-driver] +/*My block comment */ +import A; + +//--- leading-block-comment2.cpp +// RUN: %clang -std=c++20 -ccc-print-phases -fmodules-driver -Rmodules-driver \ +// RUN: %t/leading-block-comment2.cpp %t/empty.cpp 2>&1 \ +// RUN: | FileCheck %s --check-prefix=CHECK6 +// CHECK6: remark: found C++20 module usage in file '{{.*}}' [-Rmodules-driver] +/*My line comment */ import A; + +//--- inline-block-comment1.cpp +// RUN: %clang -std=c++20 -ccc-print-phases -fmodules-driver -Rmodules-driver \ +// RUN: %t/leading-block-comment1.cpp %t/empty.cpp 2>&1 \ +// RUN: | FileCheck %s --check-prefix=CHECK7 +// CHECK7: remark: found C++20 module usage in file '{{.*}}' [-Rmodules-driver] +export/*a comment*/module/*another comment*/A; + +//--- inline-block-comment2.cpp +// RUN: %clang -std=c++20 -ccc-print-phases -fmodules-driver -Rmodules-driver \ +// RUN: %t/leading-block-comment2.cpp %t/empty.cpp 2>&1 \ +// RUN: | FileCheck %s --check-prefix=CHECK8 +// CHECK8: remark: found C++20 module usage in file '{{.*}}' [-Rmodules-driver] +module/*a comment*/; + +//--- leading-directives.cpp +// RUN: %clang -std=c++23 -ccc-print-phases -fmodules-driver -Rmodules-driver \ +// RUN: %t/leading-directives.cpp %t/empty.cpp 2>&1 \ +// RUN: | FileCheck %s --check-prefix=CHECK9 +// CHECK9: remark: found C++20 module usage in file '{{.*}}' [-Rmodules-driver] +#define A +#undef A +#if A +#ifdef A +#elifdef A +#elifndef A +#endif +#ifndef A +#elif A +#else +#endif +#endif +#pragma once; +#include <iostream> +import m; + +//--- multiline-directive.cpp +// RUN: %clang -std=c++23 -ccc-print-phases -fmodules-driver -Rmodules-driver \ +// RUN: %t/multiline-directive.cpp %t/empty.cpp 2>&1 \ +// RUN: | FileCheck %s --check-prefix=CHECK10 +// CHECK10: remark: found C++20 module usage in file '{{.*}}' [-Rmodules-driver] +#define MACRO(a, \ + b) \ + call((a), \ + (b) +import a; + +//--- leading-line-splice.cpp +// RUN: %clang -std=c++23 -ccc-print-phases -fmodules-driver -Rmodules-driver \ +// RUN: %t/leading-line-splice.cpp %t/empty.cpp 2>&1 \ +// RUN: | FileCheck %s --check-prefix=CHECK11 +// CHECK11: remark: found C++20 module usage in file '{{.*}}' [-Rmodules-driver] +\ +module; + +//--- leading-line-splice-trailing-whitespace.cpp +// RUN: %clang -std=c++23 -ccc-print-phases -fmodules-driver -Rmodules-driver \ +// RUN: %t/leading-line-splice-trailing-whitespace.cpp %t/empty.cpp 2>&1 \ +// RUN: | FileCheck %s --check-prefix=CHECK12 +// CHECK12: remark: found C++20 module usage in file '{{.*}}' [-Rmodules-driver] +// v This backslash has trailing whitespace. + \ +export module A; + +//--- comment-line-splice.cpp +// RUN: %clang -std=c++23 -ccc-print-phases -fmodules-driver -Rmodules-driver \ +// RUN: %t/comment-line-splice.cpp %t/empty.cpp 2>&1 \ +// RUN: | FileCheck %s --allow-empty --check-prefix=CHECK13 +// CHECK13-NOT: remark: found C++20 module usage in file '{{.*}}' [-Rmodules-driver] +// My comment continues next-line!\ +import A; + +//--- comment-line-splice-trailing-whitespace.cpp +// RUN: %clang -std=c++23 -ccc-print-phases -fmodules-driver -Rmodules-driver \ +// RUN: %t/comment-line-splice-trailing-whitespace.cpp %t/empty.cpp 2>&1 \ +// RUN: | FileCheck %s --allow-empty --check-prefix=CHECK14 +// CHECK14-NOT: remark: found C++20 module usage in file '{{.*}}' [-Rmodules-driver] +// My comment continues next-line! This backslash has trailing whitespace. -> \ +module; + +//--- line-splice-in-directive1.cpp +// RUN: %clang -std=c++23 -ccc-print-phases -fmodules-driver -Rmodules-driver \ +// RUN: %t/line-splice-in-directive1.cpp %t/empty.cpp 2>&1 \ +// RUN: | FileCheck %s --check-prefix=CHECK15 +// CHECK15: remark: found C++20 module usage in file '{{.*}}' [-Rmodules-driver] + +module\ +; + +//--- line-splice-in-directive2.cpp +// RUN: %clang -std=c++23 -ccc-print-phases -fmodules-driver -Rmodules-driver \ +// RUN: %t/line-splice-in-directive2.cpp %t/empty.cpp 2>&1 \ +// RUN: | FileCheck %s --check-prefix=CHECK16 +// CHECK16: remark: found C++20 module usage in file '{{.*}}' [-Rmodules-driver] + +export\ + module\ + A; + +//--- no-module-usage1.cpp +// RUN: %clang -std=c++23 -ccc-print-phases -fmodules-driver -Rmodules-driver \ +// RUN: %t/no-module-usage1.cpp %t/empty.cpp 2>&1 \ +// RUN: | FileCheck %s --allow-empty --check-prefix=CHECK17 +// CHECK17-NOT: remark: found C++20 module usage in file '{{.*}}' [-Rmodules-driver] +auto main() -> int {} + +//--- no-module-usage2.cpp +// RUN: %clang -std=c++23 -ccc-print-phases -fmodules-driver -Rmodules-driver \ +// RUN: %t/no-module-usage2.cpp %t/empty.cpp 2>&1 \ +// RUN: | FileCheck %s --allow-empty --check-prefix=CHECK18 +// CHECK18-NOT: remark: found C++20 module usage in file '{{.*}}' [-Rmodules-driver] +moduleStruct{}; + +//--- no-module-usage3.cpp +// RUN: %clang -std=c++23 -ccc-print-phases -fmodules-driver -Rmodules-driver \ +// RUN: %t/no-module-usage3.cpp %t/empty.cpp 2>&1 \ +// RUN: | FileCheck %s --allow-empty --check-prefix=CHECK19 +// CHECK19-NOT: remark: found C++20 module usage in file '{{.*}}' [-Rmodules-driver] +export_struct{}; + +//--- no-module-usage-namespace-import.cpp +// RUN: %clang -std=c++23 -ccc-print-phases -fmodules-driver -Rmodules-driver \ +// RUN: %t/no-module-usage-namespace-import.cpp %t/empty.cpp 2>&1 \ +// RUN: | FileCheck %s --allow-empty --check-prefix=CHECK20 +// CHECK20-NOT: remark: found C++20 module usage in file '{{.*}}' [-Rmodules-driver] +import::inner xi = {}; + +//--- no-module-usage-namespace-module.cpp +// RUN: %clang -std=c++23 -ccc-print-phases -fmodules-driver -Rmodules-driver \ +// RUN: %t/no-module-usage-namespace-module.cpp %t/empty.cpp 2>&1 \ +// RUN: | FileCheck %s --allow-empty --check-prefix=CHECK21 +// CHECK21-NOT: remark: found C++20 module usage in file '{{.*}}' [-Rmodules-driver] +module::inner yi = {}; + +// RUN: not %clang -std=c++20 -ccc-print-phases -fmodules-driver -Rmodules-driver \ +// RUN: imaginary-file.cpp %t/empty.cpp 2>&1 \ +// RUN: | FileCheck %s --check-prefix=CHECK-NON-EXISTING-FILE-ERR +// CHECK-NON-EXISTING-FILE-ERR: clang: error: no such file or directory: 'imaginary-file.cpp' _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
