Author: Chuanqi Xu Date: 2024-09-20T09:57:46+08:00 New Revision: f41f6ea1f33c4f5e7c94f3d155e44292d1809c50
URL: https://github.com/llvm/llvm-project/commit/f41f6ea1f33c4f5e7c94f3d155e44292d1809c50 DIFF: https://github.com/llvm/llvm-project/commit/f41f6ea1f33c4f5e7c94f3d155e44292d1809c50.diff LOG: [C++20] [Modules] Offer -fmodules-embed-all-files option (#107194) See https://discourse.llvm.org/t/rfc-modules-should-we-embed-sources-to-the-bmi/81029 for details. Close https://github.com/llvm/llvm-project/issues/72383 Added: clang/test/Driver/fmodules-embed-all-files.cpp Modified: clang/docs/StandardCPlusPlusModules.rst clang/include/clang/Driver/Options.td clang/lib/Driver/ToolChains/Clang.cpp Removed: ################################################################################ diff --git a/clang/docs/StandardCPlusPlusModules.rst b/clang/docs/StandardCPlusPlusModules.rst index 2b757a807a0e6e..8e22adad15106e 100644 --- a/clang/docs/StandardCPlusPlusModules.rst +++ b/clang/docs/StandardCPlusPlusModules.rst @@ -462,6 +462,37 @@ Currently, Clang accepts the above example, though it may produce surprising results if the debugging code depends on consistent use of ``NDEBUG`` in other translation units. +Source Files Consistency +^^^^^^^^^^^^^^^^^^^^^^^^ + +Clang may open the input files\ :sup:`1`` of a BMI during the compilation. This implies that +when Clang consumes a BMI, all the input files need to be present in the original path +and with the original contents. + +To overcome these requirements and simplify cases like distributed builds and sandboxed +builds, users can use the ``-fmodules-embed-all-files`` flag to embed all input files +into the BMI so that Clang does not need to open the corresponding file on disk. + +When the ``-fmodules-embed-all-files`` flag are enabled, Clang explicitly emits the source +code into the BMI file, the contents of the BMI file contain a sufficiently verbose +representation to reproduce the original source file. + +:sup:`1`` Input files: The source files which took part in the compilation of the BMI. +For example: + +.. code-block:: c++ + + // M.cppm + module; + #include "foo.h" + export module M; + + // foo.h + #pragma once + #include "bar.h" + +The ``M.cppm``, ``foo.h`` and ``bar.h`` are input files for the BMI of ``M.cppm``. + Object definition consistency ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -484,6 +515,13 @@ fragment is disabled by default. These checks can be enabled by specifying and you encounter incorrect or missing diagnostics, please report them via the `community issue tracker <https://github.com/llvm/llvm-project/issues/>`_. +Privacy Issue +------------- + +BMIs are not and should not be treated as an information hiding mechanism. +They should always be assumed to contain all the information that was used to +create them, in a recoverable form. + ABI Impacts ----------- diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td index 021230ceed4cb4..6c6759f19f9b34 100644 --- a/clang/include/clang/Driver/Options.td +++ b/clang/include/clang/Driver/Options.td @@ -3177,6 +3177,12 @@ def modules_reduced_bmi : Flag<["-"], "fexperimental-modules-reduced-bmi">, HelpText<"Generate the reduced BMI">, MarshallingInfoFlag<FrontendOpts<"GenReducedBMI">>; +def fmodules_embed_all_files : Joined<["-"], "fmodules-embed-all-files">, + Visibility<[ClangOption, CC1Option, CLOption]>, + HelpText<"Embed the contents of all files read by this compilation into " + "the produced module file.">, + MarshallingInfoFlag<FrontendOpts<"ModulesEmbedAllFiles">>; + def fmodules_prune_interval : Joined<["-"], "fmodules-prune-interval=">, Group<i_Group>, Visibility<[ClangOption, CC1Option]>, MetaVarName<"<seconds>">, HelpText<"Specify the interval (in seconds) between attempts to prune the module cache">, @@ -7685,10 +7691,6 @@ def fmodules_embed_file_EQ : Joined<["-"], "fmodules-embed-file=">, HelpText<"Embed the contents of the specified file into the module file " "being compiled.">, MarshallingInfoStringVector<FrontendOpts<"ModulesEmbedFiles">>; -def fmodules_embed_all_files : Joined<["-"], "fmodules-embed-all-files">, - HelpText<"Embed the contents of all files read by this compilation into " - "the produced module file.">, - MarshallingInfoFlag<FrontendOpts<"ModulesEmbedAllFiles">>; defm fimplicit_modules_use_lock : BoolOption<"f", "implicit-modules-use-lock", FrontendOpts<"BuildingImplicitModuleUsesLock">, DefaultTrue, NegFlag<SetFalse>, diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp index 7e83ec0e70cbcf..0a2c7b67cc2f0f 100644 --- a/clang/lib/Driver/ToolChains/Clang.cpp +++ b/clang/lib/Driver/ToolChains/Clang.cpp @@ -4196,6 +4196,9 @@ static bool RenderModulesOptions(Compilation &C, const Driver &D, Args.ClaimAllArgs(options::OPT_fmodule_output_EQ); } + if (Args.hasArg(options::OPT_fmodules_embed_all_files)) + CmdArgs.push_back("-fmodules-embed-all-files"); + return HaveModules; } diff --git a/clang/test/Driver/fmodules-embed-all-files.cpp b/clang/test/Driver/fmodules-embed-all-files.cpp new file mode 100644 index 00000000000000..8da836a40446c4 --- /dev/null +++ b/clang/test/Driver/fmodules-embed-all-files.cpp @@ -0,0 +1,5 @@ +// RUN: %clang -std=c++20 %s -fmodules-embed-all-files -### 2>&1 | FileCheck %s +// CHECK: -fmodules-embed-all-files + +// RUN: %clang -std=c++20 %s -### 2>&1 | FileCheck %s --check-prefix=NON-EMBED +// NON-EMBED-NOT: -fmodules-embed-all-files _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
