llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang-modules Author: Chuanqi Xu (ChuanqiXu9) <details> <summary>Changes</summary> There are already 3 issues about the broken state of -fdelayed-template-parsing and C++20 modules: - https://github.com/llvm/llvm-project/issues/61068 - https://github.com/llvm/llvm-project/issues/64810 - https://github.com/llvm/llvm-project/issues/65027 The problem is more complex than I thought. I am not sure how to fix it properly now. Given the complexities and -fdelayed-template-parsing is actually an extension to support old MS codes, I think it may make sense to not enable the -fdelayed-template-parsing option by default with C++20 modules to give more user friendly experience. Users who still want -fdelayed-template-parsing can specify it explicitly. --- Full diff: https://github.com/llvm/llvm-project/pull/69431.diff 5 Files Affected: - (modified) clang/include/clang/Basic/DiagnosticDriverKinds.td (+4) - (modified) clang/include/clang/Driver/Types.h (+3) - (modified) clang/lib/Driver/ToolChains/Clang.cpp (+17-8) - (modified) clang/lib/Driver/Types.cpp (+4) - (added) clang/test/Driver/cl-delayed-template-parsing-modules.cppm (+7) ``````````diff diff --git a/clang/include/clang/Basic/DiagnosticDriverKinds.td b/clang/include/clang/Basic/DiagnosticDriverKinds.td index 9c00fa50bb95580..0a64f8573931f37 100644 --- a/clang/include/clang/Basic/DiagnosticDriverKinds.td +++ b/clang/include/clang/Basic/DiagnosticDriverKinds.td @@ -527,6 +527,10 @@ def err_test_module_file_extension_format : Error< def err_drv_module_output_with_multiple_arch : Error< "option '-fmodule-output' can't be used with multiple arch options">; +def warn_drv_delayed_template_parsing_with_module : Warning< + "-fdelayed-template-parsing is broken with C++20 modules">, + InGroup<DiagGroup<"delayed-template-parsing-in-modules">>; + def err_drv_extract_api_wrong_kind : Error< "header file '%0' input '%1' does not match the type of prior input " "in api extraction; use '-x %2' to override">; diff --git a/clang/include/clang/Driver/Types.h b/clang/include/clang/Driver/Types.h index 121b58a6b477d9b..b6a05e1ec9d624a 100644 --- a/clang/include/clang/Driver/Types.h +++ b/clang/include/clang/Driver/Types.h @@ -80,6 +80,9 @@ namespace types { /// isCXX - Is this a "C++" input (C++ and Obj-C++ sources and headers). bool isCXX(ID Id); + /// isCXXModules - Is this a standard C++ modules input. + bool isCXXModules(ID Id); + /// Is this LLVM IR. bool isLLVMIR(ID Id); diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp index 94c184435ae14de..21aee28a2b6ba9b 100644 --- a/clang/lib/Driver/ToolChains/Clang.cpp +++ b/clang/lib/Driver/ToolChains/Clang.cpp @@ -6842,14 +6842,6 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA, (!IsWindowsMSVC || IsMSVC2015Compatible))) CmdArgs.push_back("-fno-threadsafe-statics"); - // -fno-delayed-template-parsing is default, except when targeting MSVC. - // Many old Windows SDK versions require this to parse. - // FIXME: MSVC introduced /Zc:twoPhase- to disable this behavior in their - // compiler. We should be able to disable this by default at some point. - if (Args.hasFlag(options::OPT_fdelayed_template_parsing, - options::OPT_fno_delayed_template_parsing, IsWindowsMSVC)) - CmdArgs.push_back("-fdelayed-template-parsing"); - // -fgnu-keywords default varies depending on language; only pass if // specified. Args.AddLastArg(CmdArgs, options::OPT_fgnu_keywords, @@ -6872,6 +6864,23 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA, bool HaveModules = RenderModulesOptions(C, D, Args, Input, Output, Std, CmdArgs); + bool IsModulesInput = HaveModules && isCXXModules(Input.getType()); + // It is possible to compile .pcm files with C++20 modules. + IsModulesInput |= Input.getType() == types::TY_ModuleFile; + + // -fno-delayed-template-parsing is default, except when targeting MSVC. + // Many old Windows SDK versions require this to parse. + // FIXME: MSVC introduced /Zc:twoPhase- to disable this behavior in their + // compiler. We should be able to disable this by default at some point. + // FIXME: The -fdelayed-template-parsing mode is broken with C++20 modules. + if (Args.hasFlag(options::OPT_fdelayed_template_parsing, + options::OPT_fno_delayed_template_parsing, + IsWindowsMSVC && !IsModulesInput)) { + if (IsModulesInput) + D.Diag(clang::diag::warn_drv_delayed_template_parsing_with_module); + + CmdArgs.push_back("-fdelayed-template-parsing"); + } if (Args.hasFlag(options::OPT_fpch_validate_input_files_content, options::OPT_fno_pch_validate_input_files_content, false)) diff --git a/clang/lib/Driver/Types.cpp b/clang/lib/Driver/Types.cpp index 08df34ade7b6530..6977b5509c26a9b 100644 --- a/clang/lib/Driver/Types.cpp +++ b/clang/lib/Driver/Types.cpp @@ -249,6 +249,10 @@ bool types::isCXX(ID Id) { } } +bool types::isCXXModules(ID Id) { + return Id == TY_CXXModule || Id == TY_PP_CXXModule; +} + bool types::isLLVMIR(ID Id) { switch (Id) { default: diff --git a/clang/test/Driver/cl-delayed-template-parsing-modules.cppm b/clang/test/Driver/cl-delayed-template-parsing-modules.cppm new file mode 100644 index 000000000000000..fee12ae7034aed2 --- /dev/null +++ b/clang/test/Driver/cl-delayed-template-parsing-modules.cppm @@ -0,0 +1,7 @@ +// RUN: %clang_cl -std:c++20 -### -- %s 2>&1 | FileCheck %s +// RUN: %clang_cl -std:c++20 -### -fdelayed-template-parsing -- %s 2>&1 | FileCheck %s --check-prefix=CHECK-EXPLICIT + +// CHECK-NOT: -fdelayed-template-parsing + +// CHECK-EXPLICIT: -fdelayed-template-parsing +// CHECK-EXPLICIT: warning: -fdelayed-template-parsing is broken with C++20 modules `````````` </details> https://github.com/llvm/llvm-project/pull/69431 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
