[PATCH] D121175: [clang] Add -Wstart-no-unknown-warning-option/-Wend-no-unknown-warning-option.

[Daniel Thornburgh via Phabricator via cfe-commits]

mysterymath created this revision.
mysterymath added reviewers: phosek, MaskRay.
Herald added a subscriber: dexonsmith.
Herald added a project: All.
mysterymath requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.

These options allow guarding a region of warning options to allow
specify unknown options, akin to https://reviews.llvm.org/D116503.  This
allows supressing new warnings in a way that allows compilation with
older versions of clang, without globally setting
-Wno-unknown-warning-option.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D121175

Files:
  clang/docs/ClangCommandLineReference.rst
  clang/lib/Basic/Warnings.cpp
  clang/test/Frontend/warning-options.cpp


Index: clang/test/Frontend/warning-options.cpp
===================================================================
--- clang/test/Frontend/warning-options.cpp
+++ clang/test/Frontend/warning-options.cpp
@@ -1,8 +1,11 @@
 // RUN: %clang_cc1 -Wmonkey -Wno-monkey -Wno-unused-command-line-arguments \
-// RUN:        -Wno-unused-command-line-argument -Wmodule-build -Werror-vla -Rmodule-built %s 2>&1 | FileCheck %s
+// RUN:        -Wno-unused-command-line-argument -Wmodule-build -Werror-vla -Rmodule-built \
+// RUN:        -Wstart-no-unknown-warning-option -Wfoobarbaz -Wend-no-unknown-warning-option -Wplughxyzzy \
+// RUN:    %s 2>&1 | FileCheck %s
 // CHECK: unknown warning option '-Wmonkey'
 // CHECK: unknown warning option '-Wno-monkey'
 // CHECK: unknown warning option '-Wno-unused-command-line-arguments'; did you mean '-Wno-unused-command-line-argument'?
 // CHECK: unknown warning option '-Wmodule-build'; did you mean '-Wmodule-conflict'?
 // CHECK-NEXT: unknown -Werror warning specifier: '-Werror-vla'
+// CHECK: unknown warning option '-Wplughxyzzy'
 // CHECK: unknown remark option '-Rmodule-built'; did you mean '-Rmodule-build'?
Index: clang/lib/Basic/Warnings.cpp
===================================================================
--- clang/lib/Basic/Warnings.cpp
+++ clang/lib/Basic/Warnings.cpp
@@ -189,6 +189,20 @@
         continue;
       }
 
+      if (Opt == "start-no-unknown-warning-option" ||
+          Opt == "end-no-unknown-warning-option") {
+        // These flags should explicitly take effect during the report phase,
+        // not the set-diagnostic phase, since they guard the processing of
+        // specific arguments.
+        if (Report) {
+          Diags.setSeverityForGroup(Flavor, "unknown-warning-option",
+                                    Opt == "start-no-unknown-warning-option"
+                                        ? diag::Severity::Ignored
+                                        : diag::Severity::Warning);
+        }
+        continue;
+      }
+
       if (Report) {
         if (DiagIDs->getDiagnosticsInGroup(Flavor, Opt, _Diags))
           EmitUnknownDiagWarning(Diags, Flavor, isPositive ? "-W" : "-Wno-",
Index: clang/docs/ClangCommandLineReference.rst
===================================================================
--- clang/docs/ClangCommandLineReference.rst
+++ clang/docs/ClangCommandLineReference.rst
@@ -1367,6 +1367,10 @@
 
 .. option:: -Wdeprecated, -Wno-deprecated
 
+Within the given flag region, prevent warning about unknown warning enable/disable flags.
+
+.. option:: -Wstart-no-unknown-warning-option, -Wend-no-unknown-warning-option
+
 Enable warnings for deprecated constructs and define \_\_DEPRECATED
 
 .. option:: -Wframe-larger-than=<arg>, -Wframe-larger-than


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D121175.413659.patch
Type: text/x-patch
Size: 2761 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20220308/a9360d7b/attachment-0001.bin>