[PATCH] D135750: [clang][Interp] Track initialization state of local variables

[Timm Bäder via Phabricator via cfe-commits]

tbaeder marked 4 inline comments as done.
tbaeder added inline comments.


================
Comment at: clang/lib/AST/Interp/ByteCodeExprGen.cpp:835
     IsTemporary = true;
     Ty = E->getType();
   }
----------------
shafik wrote:
> tbaeder wrote:
> > shafik wrote:
> > > Do we really want to the type of the expression? If we have a `ValueDecl` don't we want that type? I think they should be the same, do you have any examples where the expression is the type we want? I am looking at the AST from ` int x = 1+1L;` 
> > > 
> > > https://godbolt.org/z/q3Tr7Kxoq
> > I don't have a counter example but I didn't write that line either. The Expr case is for temporary values created for AST expressions, not sure what other type to use.
> I think it should be an `else if` we either have a `Decl` or an `Expr` right?
Yes, that should work as well.


================
Comment at: clang/lib/AST/Interp/ByteCodeStmtGen.cpp:408
     // Compile the initializer in its own scope.
-    {
+    if (Init) {
       ExprScope<Emitter> Scope(this);
----------------
shafik wrote:
> So by moving the check for `Init` forward, we will still allocate but we may not initialize.
Correct.


================
Comment at: clang/lib/AST/Interp/Interp.h:918
     return false;
+  if (!Ptr.isRoot())
+    Ptr.initialize();
----------------
shafik wrote:
> Can you explain what is going on here? Why do we need to initialize if it is not root?
Root means that `Base == 0`, so it cannot have a `InlineDescriptor` before the `Base` offset. That is mainly the case for global variables.


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  https://reviews.llvm.org/D135750/new/

https://reviews.llvm.org/D135750