https://github.com/mizvekov updated https://github.com/llvm/llvm-project/pull/124997
>From 087997a38f4c64f7c305142ca630777d35b6a126 Mon Sep 17 00:00:00 2001 From: Matheus Izvekov <mizve...@gmail.com> Date: Wed, 29 Jan 2025 19:34:24 -0300 Subject: [PATCH] [clang] C++20 Modules: document how to perform automated reductions --- clang/docs/StandardCPlusPlusModules.rst | 24 +++++++++++++++++++++++- 1 file changed, 23 insertions(+), 1 deletion(-) diff --git a/clang/docs/StandardCPlusPlusModules.rst b/clang/docs/StandardCPlusPlusModules.rst index 93edce0cf90b76e..c209bc0cc192485 100644 --- a/clang/docs/StandardCPlusPlusModules.rst +++ b/clang/docs/StandardCPlusPlusModules.rst @@ -710,7 +710,7 @@ Before Clang 19, a change in BMI of any (transitive) dependency would cause the outputs of the BMI to change. Starting with Clang 19, changes to non-direct dependencies should not directly affect the output BMI, unless they affect the results of the compilations. We expect that there are many more opportunities -for this optimization than we currently have realized and would appreaciate +for this optimization than we currently have realized and would appreciate feedback about missed optimization opportunities. For example, .. code-block:: c++ @@ -2072,3 +2072,25 @@ Interoperability with Clang Modules We **wish** to support Clang modules and standard C++ modules at the same time, but the mixing them together is not well used/tested yet. Please file new GitHub issues as you find interoperability problems. + +Finding reduced test cases +-------------------------- + +When the user encounters a problem with the implementation of standard modules, +it's helpful to attach a reduced test case to the issue report. + +This reduction is hard, as it can't avoid the dependency on multiple files, +unlike most issues which can be reproduced within a single translation unit. + +If you are familiar with performing automated reductions using tools like +c-reduce, you can use `cvise <https://github.com/marxin/cvise>`_ to accomplish this +reduction. + +Much in the same way as creduce, cvise takes an interestingness test +in addition to the source code. In the latter case, you can create an +interestingness test which uses your project's build system to perform +the build part, and cvise will accept multiple source files or directories, +and will take turns reducing each, which is something creduce does not support. + +Be aware that this can be highly compute intensive, but on the upside no manual +intervention is required. _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
