r306715 - Fixed -Wexceptions derived-to-base false positives

[Stephan Bergmann via cfe-commits]

Author: sberg
Date: Thu Jun 29 10:58:59 2017
New Revision: 306715

URL: http://llvm.org/viewvc/llvm-project?rev=306715&view=rev
Log:
Fixed -Wexceptions derived-to-base false positives

...as introduced with recent <https://reviews.llvm.org/D33333> "Emit warning
when throw exception in destruct or dealloc functions which has a (possible
implicit) noexcept specifier".  (The equivalent of the goodReference case hit
when building LibreOffice.)

(These warnings are apparently only emitted when no errors have yet been
encountered, so it didn't work to add the test code to the end of the existing
clang/test/SemaCXX/exceptions.cpp.)

Added:
    cfe/trunk/test/SemaCXX/exception-warnings.cpp
Modified:
    cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp

Modified: cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp?rev=306715&r1=306714&r2=306715&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp (original)
+++ cfe/trunk/lib/Sema/AnalysisBasedWarnings.cpp Thu Jun 29 10:58:59 2017
@@ -305,10 +305,14 @@ static bool isThrowCaught(const CXXThrow
     CaughtType = CaughtType->castAs<ReferenceType>()
                      ->getPointeeType()
                      ->getUnqualifiedDesugaredType();
+  if (ThrowType->isPointerType() && CaughtType->isPointerType()) {
+    ThrowType = ThrowType->getPointeeType()->getUnqualifiedDesugaredType();
+    CaughtType = CaughtType->getPointeeType()->getUnqualifiedDesugaredType();
+  }
   if (CaughtType == ThrowType)
     return true;
   const CXXRecordDecl *CaughtAsRecordType =
-      CaughtType->getPointeeCXXRecordDecl();
+      CaughtType->getAsCXXRecordDecl();
   const CXXRecordDecl *ThrowTypeAsRecordType = ThrowType->getAsCXXRecordDecl();
   if (CaughtAsRecordType && ThrowTypeAsRecordType)
     return ThrowTypeAsRecordType->isDerivedFrom(CaughtAsRecordType);

Added: cfe/trunk/test/SemaCXX/exception-warnings.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/exception-warnings.cpp?rev=306715&view=auto
==============================================================================
--- cfe/trunk/test/SemaCXX/exception-warnings.cpp (added)
+++ cfe/trunk/test/SemaCXX/exception-warnings.cpp Thu Jun 29 10:58:59 2017
@@ -0,0 +1,36 @@
+// RUN: %clang_cc1 -fcxx-exceptions -fexceptions -fsyntax-only -verify %s
+
+struct B {};
+struct D: B {};
+void goodPlain() throw () {
+  try {
+    throw D();
+  } catch (B) {}
+}
+void goodReference() throw () {
+  try {
+    throw D();
+  } catch (B &) {}
+}
+void goodPointer() throw () {
+  D d;
+  try {
+    throw &d;
+  } catch (B *) {}
+}
+void badPlain() throw () { // expected-note {{non-throwing function declare here}}
+  try {
+    throw B(); // expected-warning {{'badPlain' has a non-throwing exception specification but can still throw, resulting in unexpected program termination}}
+  } catch (D) {}
+}
+void badReference() throw () { // expected-note {{non-throwing function declare here}}
+  try {
+    throw B(); // expected-warning {{'badReference' has a non-throwing exception specification but can still throw, resulting in unexpected program termination}}
+  } catch (D &) {}
+}
+void badPointer() throw () { // expected-note {{non-throwing function declare here}}
+  B b;
+  try {
+    throw &b; // expected-warning {{'badPointer' has a non-throwing exception specification but can still throw, resulting in unexpected program termination}}
+  } catch (D *) {}
+}