Switch to a different workaround for unimplementability of P0145R3 in MS ABIs.
Instead of ignoring the evaluation order rule, ignore the "destroy parameters
in reverse construction order" rule for the small number of problematic cases.
This only causes incorrect behavior in the rare case where both parameters to
an overloaded operator <<, >>, ->*, &&, ||, or comma are of class type with
non-trivial destructor, and the program is depending on those parameters being
destroyed in reverse construction order.
We could do a little better here by reversing the order of parameter
destruction for those functions (and reversing the argument evaluation order
for all direct calls, not just those with operator syntax), but that is not a
complete solution to the problem, as the same situation can be reached by an
indirect function call.
Approach reviewed off-line by rnk.
llvm-svn: 282777
diff --git a/clang/www/cxx_status.html b/clang/www/cxx_status.html
index 1fe28d5..170fc60 100644
--- a/clang/www/cxx_status.html
+++ b/clang/www/cxx_status.html
@@ -740,14 +740,12 @@
<span id="p0136">(9): This is the resolution to a Defect Report, so is applied
to all language versions supporting inheriting constructors.
</span><br>
-<span id="p0145">(10): Under the MS ABI, this feature is not fully implementable,
-because the calling convention requires that function parameters are destroyed
-from left to right in the callee. In order to guarantee that destruction order
-is reverse construction order, the operands of overloaded
+<span id="p0145">(10): Under the MS ABI, function parameters are destroyed from
+left to right in the callee. As a result, function parameters in calls to
<tt>operator<<</tt>, <tt>operator>></tt>, <tt>operator->*</tt>,
<tt>operator&&</tt>, <tt>operator||</tt>, and <tt>operator,</tt>
-functions are evaluated right-to-left under the MS ABI when called using operator
-syntax, not left-to-right as P0145R3 requires.
+functions using expression syntax are no longer guaranteed to be destroyed in
+reverse construction order in that ABI.
</span>
</p>
</details>
