[PATCH] D109862: Don't diagnose unused but set when the Cleanup attribute is used.

[Michael Benfield via Phabricator via cfe-commits]

mbenfield updated this revision to Diff 373069.
mbenfield added a comment.

Added a test case.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D109862/new/

https://reviews.llvm.org/D109862

Files:
  clang/lib/Sema/SemaDecl.cpp
  clang/test/Sema/warn-unused-but-set-variables.c


Index: clang/test/Sema/warn-unused-but-set-variables.c
===================================================================
--- clang/test/Sema/warn-unused-but-set-variables.c
+++ clang/test/Sema/warn-unused-but-set-variables.c
@@ -49,3 +49,13 @@
   x = 0;
   (void) sizeof(x);
 }
+
+void for_cleanup(int *x) {
+  *x = 0;
+}
+
+void f3(void) {
+  // Don't warn if the __cleanup__ attribute is used.
+  __attribute__((__cleanup__(for_cleanup))) int x;
+  x = 5;
+}
Index: clang/lib/Sema/SemaDecl.cpp
===================================================================
--- clang/lib/Sema/SemaDecl.cpp
+++ clang/lib/Sema/SemaDecl.cpp
@@ -1921,8 +1921,10 @@
 }
 
 void Sema::DiagnoseUnusedButSetDecl(const VarDecl *VD) {
-  // If it's not referenced, it can't be set.
-  if (!VD->isReferenced() || !VD->getDeclName() || VD->hasAttr<UnusedAttr>())
+  // If it's not referenced, it can't be set. If it has the Cleanup attribute,
+  // it's not really unused.
+  if (!VD->isReferenced() || !VD->getDeclName() || VD->hasAttr<UnusedAttr>() ||
+      VD->hasAttr<CleanupAttr>())
     return;
 
   const auto *Ty = VD->getType().getTypePtr()->getBaseElementTypeUnsafe();



Index: clang/test/Sema/warn-unused-but-set-variables.c
===================================================================
--- clang/test/Sema/warn-unused-but-set-variables.c
+++ clang/test/Sema/warn-unused-but-set-variables.c
@@ -49,3 +49,13 @@
   x = 0;
   (void) sizeof(x);
 }
+
+void for_cleanup(int *x) {
+  *x = 0;
+}
+
+void f3(void) {
+  // Don't warn if the __cleanup__ attribute is used.
+  __attribute__((__cleanup__(for_cleanup))) int x;
+  x = 5;
+}
Index: clang/lib/Sema/SemaDecl.cpp
===================================================================
--- clang/lib/Sema/SemaDecl.cpp
+++ clang/lib/Sema/SemaDecl.cpp
@@ -1921,8 +1921,10 @@
 }
 
 void Sema::DiagnoseUnusedButSetDecl(const VarDecl *VD) {
-  // If it's not referenced, it can't be set.
-  if (!VD->isReferenced() || !VD->getDeclName() || VD->hasAttr<UnusedAttr>())
+  // If it's not referenced, it can't be set. If it has the Cleanup attribute,
+  // it's not really unused.
+  if (!VD->isReferenced() || !VD->getDeclName() || VD->hasAttr<UnusedAttr>() ||
+      VD->hasAttr<CleanupAttr>())
     return;
 
   const auto *Ty = VD->getType().getTypePtr()->getBaseElementTypeUnsafe();

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