Refactored dtor sanitizing into EHScopeStack

Summary:
Dtor sanitization handled amidst other dtor cleanups,
between cleaning bases and fields. Sanitizer call pushed onto
stack of cleanup operations.

Reviewers: eugenis, kcc

Differential Revision: http://reviews.llvm.org/D12022

Refactoring dtor sanitizing emission order.

- Support multiple inheritance by poisoning after
 member destructors are invoked, and before base
 class destructors are invoked.
- Poison for virtual destructor and virtual bases.
- Repress dtor aliasing when sanitizing in dtor.
- CFE test for dtor aliasing, and repression of aliasing in dtor
 code generation.
- Poison members on field-by-field basis, with collective poisoning
 of trivial members when possible.
- Check msan flags and existence of fields, before dtor sanitizing,
 and when determining if aliasing is allowed.
- Testing sanitizing bit fields.

llvm-svn: 246815

1 files changed, 6 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGCXX.cpp b/clang/lib/CodeGen/CGCXX.cpp
index 7fd307b4161..cb8700ec563 100644
--- a/clang/lib/CodeGen/CGCXX.cpp
+++ b/clang/lib/CodeGen/CGCXX.cpp
@@ -39,6 +39,12 @@ bool CodeGenModule::TryEmitBaseDestructorAsAlias(const CXXDestructorDecl *D) {
   if (getCodeGenOpts().OptimizationLevel == 0)
     return true;
 
+  // If sanitizing memory to check for use-after-dtor, do not emit as
+  //  an alias, unless this class owns no members.
+  if (getCodeGenOpts().SanitizeMemoryUseAfterDtor &&
+      !D->getParent()->field_empty())
+    return true;
+
   // If the destructor doesn't have a trivial body, we have to emit it
   // separately.
   if (!D->hasTrivialBody())