[clang-tidy] readability-redundant-declaration: fix false positive with C "extern inline"

Summary:
readability-redundant-declaration was diagnosing a redundant declaration
on "extern inline void f();", which is needed in C code to force an external definition
of the inline function f. (This is different to how inline behaves in C++).

Reviewers: alexfh, danielmarjamaki

Subscribers: xazax.hun, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D61700

llvm-svn: 360613

1 files changed, 8 insertions, 2 deletions

diff --git a/clang-tools-extra/clang-tidy/readability/RedundantDeclarationCheck.cpp b/clang-tools-extra/clang-tidy/readability/RedundantDeclarationCheck.cpp
index ff3809a2ff1..ab2e15b0723 100644
--- a/clang-tools-extra/clang-tidy/readability/RedundantDeclarationCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/RedundantDeclarationCheck.cpp
@@ -17,6 +17,10 @@ namespace clang {
 namespace tidy {
 namespace readability {
 
+AST_MATCHER(FunctionDecl, doesDeclarationForceExternallyVisibleDefinition) {
+  return Node.doesDeclarationForceExternallyVisibleDefinition();
+}
+
 RedundantDeclarationCheck::RedundantDeclarationCheck(StringRef Name,
                                                      ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context),
@@ -25,8 +29,10 @@ RedundantDeclarationCheck::RedundantDeclarationCheck(StringRef Name,
 void RedundantDeclarationCheck::registerMatchers(MatchFinder *Finder) {
   Finder->addMatcher(
       namedDecl(anyOf(varDecl(unless(isDefinition())),
-                      functionDecl(unless(anyOf(isDefinition(), isDefaulted(),
-                                                hasParent(friendDecl()))))))
+                      functionDecl(unless(anyOf(
+                          isDefinition(), isDefaulted(),
+                          doesDeclarationForceExternallyVisibleDefinition(),
+                          hasParent(friendDecl()))))))
           .bind("Decl"),
       this);
 }