[clang-tidy][libc] Fix namespace check with macro

[michaelrj-google]

The name of the namespace for LLVM's libc is now provided by a macro.
The ImplementationNamespaceCheck was updated to handle this, but the
CalleeNamespaceCheck was missed. This patch updates the
CalleeNamespaceCheck to handle the macro.

[llvmbot]

@llvm/pr-subscribers-clang-tidy

Changes

The name of the namespace for LLVM's libc is now provided by a macro.
The ImplementationNamespaceCheck was updated to handle this, but the
CalleeNamespaceCheck was missed. This patch updates the
CalleeNamespaceCheck to handle the macro.

---

Full diff: https://github.com/llvm/llvm-project/pull/68134.diff

1 Files Affected:

• (modified) clang-tools-extra/clang-tidy/llvmlibc/CalleeNamespaceCheck.cpp (+6-4)

diff --git a/clang-tools-extra/clang-tidy/llvmlibc/CalleeNamespaceCheck.cpp b/clang-tools-extra/clang-tidy/llvmlibc/CalleeNamespaceCheck.cpp
index 98ae857b589fd64..7ad4b5fb7f043ab 100644
--- a/clang-tools-extra/clang-tidy/llvmlibc/CalleeNamespaceCheck.cpp
+++ b/clang-tools-extra/clang-tidy/llvmlibc/CalleeNamespaceCheck.cpp
@@ -45,9 +45,10 @@ void CalleeNamespaceCheck::check(const MatchFinder::MatchResult &Result) {
   if (FuncDecl->getBuiltinID() != 0)
     return;
 
-  // If the outermost namespace of the function is __llvm_libc, we're good.
+  // If the outermost namespace of the function starts with __llvm_libc, we're
+  // good.
   const auto *NS = dyn_cast<NamespaceDecl>(getOutermostNamespace(FuncDecl));
-  if (NS && NS->getName() == "__llvm_libc")
+  if (NS && NS->getName().starts_with("__llvm_libc"))
     return;
 
   const DeclarationName &Name = FuncDecl->getDeclName();
@@ -55,8 +56,9 @@ void CalleeNamespaceCheck::check(const MatchFinder::MatchResult &Result) {
       IgnoredFunctions.contains(Name.getAsIdentifierInfo()->getName()))
     return;
 
-  diag(UsageSiteExpr->getBeginLoc(), "%0 must resolve to a function declared "
-                                     "within the '__llvm_libc' namespace")
+  diag(UsageSiteExpr->getBeginLoc(),
+       "%0 must resolve to a function declared "
+       "within the '__llvm_libc' namespace (use macro `LIBC_NAMESPACE`)")
       << FuncDecl;
 
   diag(FuncDecl->getLocation(), "resolves to this declaration",

[HerrCai0907]

LGTM. Please update the release notes.

[EugeneZelenko]

Shouldn't documentation be updated too?

[PiotrZSL]

Order of changes, test, documentation is missing

[gchatelet]

It would be ideal to move the following lines to a shared header and use them in both implementations.

[michaelrj-google]

I've addressed the comments with my latest commit

[PiotrZSL]

From functional point of view looks fine, could be more strict but should still work.