[clang] 88f9ac3 - [doc] [C++20] [Modules] Add docs and release notes for '-Wdecls-in-multiple-modules'

[Chuanqi Xu via cfe-commits]

Author: Chuanqi Xu
Date: 2024-08-26T10:52:05+08:00
New Revision: 88f9ac380d8b40742aea11c8278652711261abff

URL: https://github.com/llvm/llvm-project/commit/88f9ac380d8b40742aea11c8278652711261abff
DIFF: https://github.com/llvm/llvm-project/commit/88f9ac380d8b40742aea11c8278652711261abff.diff

LOG: [doc] [C++20] [Modules] Add docs and release notes for '-Wdecls-in-multiple-modules'

As the title shows.

Added: 
    

Modified: 
    clang/docs/ReleaseNotes.rst
    clang/docs/StandardCPlusPlusModules.rst

Removed: 
    


################################################################################
diff  --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 6e1db41a55cbe0..2c6c7e083b9c91 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -249,6 +249,11 @@ Improvements to Clang's diagnostics
   a warning which defaults to being an error, is enabled by default, and is
   also controlled by the now-deprecated ``-fheinous-gnu-extensions`` flag.
 
+- Added the ``-Wdecls-in-multiple-modules`` option to assist users to identify
+  multiple declarations in 
diff erent modules, which is the major reason of the slow
+  compilation speed with modules. This warning is disabled by default and it needs
+  to be explicitly enabled or by ``-Weverything``.
+
 Improvements to Clang's time-trace
 ----------------------------------
 

diff  --git a/clang/docs/StandardCPlusPlusModules.rst b/clang/docs/StandardCPlusPlusModules.rst
index 1469feb3ad45bd..2b757a807a0e6e 100644
--- a/clang/docs/StandardCPlusPlusModules.rst
+++ b/clang/docs/StandardCPlusPlusModules.rst
@@ -894,6 +894,9 @@ approach:
 Reducing the duplication from textual includes is what improves compile-time
 performance.
 
+To help users to identify such issues, we add a warning ``-Wdecls-in-multiple-modules``.
+This warning is disabled by default and it needs to be explicitly enabled or by ``-Weverything``.
+
 Transitioning to modules
 ------------------------