If we see a variable declaration (aka. DeclStmt), and the VarRegion it
declared doesn't have Stack memspace, we assumed that it must be a local
static variable.
However, the declared variable may be an extern declaration of a global.
In this patch, let's admit that local extern declarations are a thing.
For the sake of completeness, I also added one more test for
thread_locals - which are implicitly considered statics btw. (the
`isStaticLocal()` correctly also considers thread locals as local
statics).
Fixes#124975
This API is used by checkers (and other entities) in order to track where does
a value originate from, by jumping from an expression value of which is equal
to that value to the expression from which this value has "appeared". For
example, it may be an lvalue from which the rvalue was loaded, or a function
call from which the dereferenced pointer was returned.
The function now avoids incorrectly unwrapping implicit lvalue-to-rvalue casts,
which caused crashes and incorrect intermediate diagnostic pieces. It also no
longer relies on how the expression is written when guessing what it means.
Fixes pr34373 and pr34731.
rdar://problem/33594502
Differential Revision: https://reviews.llvm.org/D37023
llvm-svn: 314287
