ehsan added a comment.
In http://reviews.llvm.org/D16465#333688, @rnk wrote:
> Your code won't catch this test case:
>
> static int x;
> extern inline const bool *f() {
> static const bool p = !&x;
> return &p;
> }
>
> Getting this exactly right is going to be a challenge. =/
Oh you're right. I need to spend some more time comparing our behavior with
cl's, it seems...
================
Comment at: include/clang/Basic/DiagnosticASTKinds.td:151
@@ -150,1 +150,3 @@
"%plural{1:byte|:bytes}1">;
+def note_constexpr_microsoft_abi_declrefexpr : Note<
+ "the constant expression cannot contain a reference to a variable as a
Microsoft "
----------------
rnk wrote:
> We should add this test case and decide what to do with it:
> static int x;
> inline int **f() {
> static constexpr int *p = true ? 0 : &x;
> return &p;
> }
> Currently, in your patch, this diagnostic will come out. MSVC compiles this
> to guarded, dynamic initialization, despite the constexpr. ;_;
>
> David thinks we should just give the user the real deal constexpr behavior,
> even though it's ABI incompatible.
One solution to this would be to create a variation of `evaluateValue()` which
activates this new behavior and only use it from
`CodeGenModule::EmitConstantInit()`, so that the behavior of `evaluateValue()`
in this context doesn't change. How does that sound?
By the way, I just realized that
`CheckPotentialExpressionContainingDeclRefExpr()` eats this diagnostic because
of the `SpeculativeLookForDeclRefExprRAII` object. Should I propagate it up
from `CheckPotentialExpressionContainingDeclRefExpr()` to make it user visible?
Right now the test case above only emits "constexpr variable 'p' must be
initialized by a constant expression" without any notes.
================
Comment at: lib/AST/ExprConstant.cpp:9008
@@ -8917,1 +9007,3 @@
+ if (Ctx.getTargetInfo().getCXXABI().isMicrosoft())
+ InitInfo.useMicrosoftABI();
----------------
rnk wrote:
> This should be limited in scope to only apply to static locals. We should be
> able to statically initialize globals.
Right, my bad!
http://reviews.llvm.org/D16465
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