Commit Graph

7 Commits

Author SHA1 Message Date
Richard Smith a560ccf2af 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
2016-09-29 21:30:12 +00:00
Richard Smith 762672a73a Re-commit r282556, reverted in r282564, with a fix to CallArgList::addFrom to
function correctly when targeting MS ABIs (this appears to have never mattered
prior to this change).

Update test case to always cover both 32-bit and 64-bit Windows ABIs, since
they behave somewhat differently from each other here.

Update test case to also cover operators , && and ||, which it appears are also
affected by P0145R3 (they're not explicitly called out by the design document,
but this is the emergent behavior of the existing wording).


Original commit message:

P0145R3 (C++17 evaluation order tweaks): evaluate the right-hand side of
assignment and compound-assignment operators before the left-hand side. (Even
if it's an overloaded operator.)

This completes the implementation of P0145R3 + P0400R0 for all targets except
Windows, where the evaluation order guarantees for <<, >>, and ->* are
unimplementable as the ABI requires the function arguments are evaluated from
right to left (because parameter destructors are run from left to right in the
callee).

llvm-svn: 282619
2016-09-28 19:09:10 +00:00
Richard Smith 4499145a5f Revert r282556. This change made several bots unhappy.
llvm-svn: 282564
2016-09-28 02:20:06 +00:00
Richard Smith 97a616d624 P0145R3 (C++17 evaluation order tweaks): evaluate the right-hand side of
assignment and compound-assignment operators before the left-hand side. (Even
if it's an overloaded operator.)

This completes the implementation of P0145R3 + P0400R0 for all targets except
Windows, where the evaluation order guarantees for <<, >>, and ->* are
unimplementable as the ABI requires the function arguments are evaluated from
right to left (because parameter destructors are run from left to right in the
callee).

llvm-svn: 282556
2016-09-27 23:44:22 +00:00
Richard Smith 689bb78631 Defend test against differences between 32-bit and 64-bit MSABI manglings.
llvm-svn: 282463
2016-09-27 00:52:29 +00:00
Richard Smith bde62d78e9 P0145R3 (C++17 evaluation order tweaks): evaluate the base expression before
the pointer-to-member expression in calls through .* and ->* expressions.

llvm-svn: 282457
2016-09-26 23:56:57 +00:00
Richard Smith 9e67b9922b P0145R3 (C++17 evaluation order tweaks): consistently emit the LHS of array
subscripting before the RHS, regardless of which is the base and which is the
index.

llvm-svn: 282453
2016-09-26 23:49:47 +00:00