Allow 'inline' on some declarations in MS compatibility mode (#125250)
Microsoft allows the 'inline' specifier on a typedef of a function type
in C modes. This is used by a system header (ufxclient.h), so instead
of giving a hard error, we diagnose with a warning. C++ mode and non-
Microsoft compatibility modes are not impacted.
Fixes https://github.com/llvm/llvm-project/issues/124869
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 8c29043..a220e57 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -83,6 +83,9 @@
C Language Changes
------------------
+- Clang now allows an ``inline`` specifier on a typedef declaration of a
+ function type in Microsoft compatibility mode. #GH124869
+
C2y Feature Support
^^^^^^^^^^^^^^^^^^^
diff --git a/clang/include/clang/Basic/DiagnosticGroups.td b/clang/include/clang/Basic/DiagnosticGroups.td
index 527e588..abb5750 100644
--- a/clang/include/clang/Basic/DiagnosticGroups.td
+++ b/clang/include/clang/Basic/DiagnosticGroups.td
@@ -1304,6 +1304,8 @@
def MicrosoftInitFromPredefined : DiagGroup<"microsoft-init-from-predefined">;
def MicrosoftStringLiteralFromPredefined : DiagGroup<
"microsoft-string-literal-from-predefined">;
+def MicrosoftInlineOnNonFunction : DiagGroup<
+ "microsoft-inline-on-non-function">;
// Aliases.
def : DiagGroup<"msvc-include", [MicrosoftInclude]>;
@@ -1322,7 +1324,7 @@
MicrosoftConstInit, MicrosoftVoidPseudoDtor, MicrosoftAnonTag,
MicrosoftCommentPaste, MicrosoftEndOfFile, MicrosoftStaticAssert,
MicrosoftInitFromPredefined, MicrosoftStringLiteralFromPredefined,
- MicrosoftInconsistentDllImport]>;
+ MicrosoftInconsistentDllImport, MicrosoftInlineOnNonFunction]>;
def ClangClPch : DiagGroup<"clang-cl-pch">;
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 2ac3879..00a94eb 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -482,6 +482,8 @@
InGroup<DiagGroup<"out-of-scope-function">>;
def err_inline_non_function : Error<
"'inline' can only appear on functions%select{| and non-local variables}0">;
+def warn_ms_inline_non_function : ExtWarn<err_inline_non_function.Summary>,
+ InGroup<MicrosoftInlineOnNonFunction>;
def err_noreturn_non_function : Error<
"'_Noreturn' can only appear on functions">;
def warn_qual_return_type : Warning<
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index f7b8b19..1755b37 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -6681,7 +6681,10 @@
DiagnoseFunctionSpecifiers(D.getDeclSpec());
if (D.getDeclSpec().isInlineSpecified())
- Diag(D.getDeclSpec().getInlineSpecLoc(), diag::err_inline_non_function)
+ Diag(D.getDeclSpec().getInlineSpecLoc(),
+ (getLangOpts().MSVCCompat && !getLangOpts().CPlusPlus)
+ ? diag::warn_ms_inline_non_function
+ : diag::err_inline_non_function)
<< getLangOpts().CPlusPlus17;
if (D.getDeclSpec().hasConstexprSpecifier())
Diag(D.getDeclSpec().getConstexprSpecLoc(), diag::err_invalid_constexpr)
diff --git a/clang/test/Sema/MicrosoftCompatibility.c b/clang/test/Sema/MicrosoftCompatibility.c
index 9a1f050..8d402d5 100644
--- a/clang/test/Sema/MicrosoftCompatibility.c
+++ b/clang/test/Sema/MicrosoftCompatibility.c
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 %s -fsyntax-only -Wno-unused-value -Wmicrosoft -verify -fms-compatibility -DMSVCCOMPAT -triple i686-pc-win32
-// RUN: %clang_cc1 %s -fsyntax-only -Wno-unused-value -Wmicrosoft -verify -fms-extensions -triple i686-pc-win32
+// RUN: %clang_cc1 %s -fsyntax-only -Wno-unused-value -Wmicrosoft -verify=expected,compat -fms-compatibility -DMSVCCOMPAT -triple i686-pc-win32
+// RUN: %clang_cc1 %s -fsyntax-only -Wno-unused-value -Wmicrosoft -verify=expected,ext -fms-extensions -triple i686-pc-win32
#ifdef MSVCCOMPAT
enum ENUM1; // expected-warning {{forward references to 'enum' types are a Microsoft extension}}
@@ -35,3 +35,15 @@
#else
size_t x; // expected-error {{unknown type name 'size_t'}}
#endif
+
+/* Microsoft allows inline, __inline, and __forceinline to appear on a typedef
+ of a function type; this is used in their system headers such as ufxclient.h
+ See GitHub #124869 for more details.
+ */
+typedef int inline Foo1(int); // compat-warning {{'inline' can only appear on functions}} \
+ ext-error {{'inline' can only appear on functions}}
+typedef int __inline Foo2(int); // compat-warning {{'inline' can only appear on functions}} \
+ ext-error {{'inline' can only appear on functions}}
+typedef int __forceinline Foo(int); // compat-warning {{'inline' can only appear on functions}} \
+ ext-error {{'inline' can only appear on functions}} \
+ expected-warning {{'__forceinline' attribute only applies to functions and statements}}
diff --git a/clang/test/Sema/MicrosoftCompatibility.cpp b/clang/test/Sema/MicrosoftCompatibility.cpp
index 90a45df..391977e 100644
--- a/clang/test/Sema/MicrosoftCompatibility.cpp
+++ b/clang/test/Sema/MicrosoftCompatibility.cpp
@@ -8,3 +8,10 @@
};
char * cls::* __uptr wrong2 = &cls::m; // expected-error {{'__uptr' attribute cannot be used with pointers to members}}
+
+// Microsoft allows inline, __inline, and __forceinline to appear on a typedef
+// of a function type, but only in C. See GitHub #124869 for more details.
+typedef int inline Foo1(int); // expected-error {{'inline' can only appear on functions}}
+typedef int __inline Foo2(int); // expected-error {{'inline' can only appear on functions}}
+typedef int __forceinline Foo(int); // expected-error {{'inline' can only appear on functions}} \
+ expected-warning {{'__forceinline' attribute only applies to functions and statements}}
