[PATCH] D39013: [CFG] Relax Wexceptions warning on rethrow

[Erich Keane via Phabricator via cfe-commits]

erichkeane created this revision.

As reported here: https://bugs.llvm.org/show_bug.cgi?id=34973

"catch(...)" should catch EVERYTHING, even a rethrow.  This
patch changes the order of the checks to ensure that the
catch(...) will catch everything.


https://reviews.llvm.org/D39013

Files:
  lib/Sema/AnalysisBasedWarnings.cpp
  test/SemaCXX/warn-throw-out-noexcept-func.cpp


Index: lib/Sema/AnalysisBasedWarnings.cpp
===================================================================
--- lib/Sema/AnalysisBasedWarnings.cpp
+++ lib/Sema/AnalysisBasedWarnings.cpp
@@ -289,14 +289,14 @@
 
 static bool isThrowCaught(const CXXThrowExpr *Throw,
                           const CXXCatchStmt *Catch) {
+  const Type *CaughtType = Catch->getCaughtType().getTypePtrOrNull();
+  if (!CaughtType)
+    return true;
   const Type *ThrowType = nullptr;
   if (Throw->getSubExpr())
     ThrowType = Throw->getSubExpr()->getType().getTypePtrOrNull();
   if (!ThrowType)
     return false;
-  const Type *CaughtType = Catch->getCaughtType().getTypePtrOrNull();
-  if (!CaughtType)
-    return true;
   if (ThrowType->isReferenceType())
     ThrowType = ThrowType->castAs<ReferenceType>()
                     ->getPointeeType()
Index: test/SemaCXX/warn-throw-out-noexcept-func.cpp
===================================================================
--- test/SemaCXX/warn-throw-out-noexcept-func.cpp
+++ test/SemaCXX/warn-throw-out-noexcept-func.cpp
@@ -239,9 +239,11 @@
   } catch (const S &s) {
   }
 }
-void o_ShouldDiag() noexcept { //expected-note {{function declared non-throwing here}}
+// As seen in p34973, this should not throw the warning.  If there is an active
+// exception, catch(...) catches everything. 
+void o_ShouldDiag() noexcept {
   try {
-    throw; //expected-warning {{has a non-throwing exception specification but}}
+    throw;
   } catch (...) {
   }
 }


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