[LifetimeSafety] Detect expiry of loans to trivially destructed types (#168855)

Handling Trivially Destructed Types

This PR uses `AddLifetime` to handle expiry of loans to trivially
destructed types.

Example:
```cpp
int * trivial_uar(){
    int *ptr;
    int x = 1;
    ptr = &x;
    return ptr;
}
```

The CFG created now has an Expire Fact for trivially destructed types:
```
Function: trivial_uar
  Block B2:
  End of Block
  Block B1:
    Issue (0 (Path: x), ToOrigin: 0 (Expr: DeclRefExpr))
    OriginFlow (Dest: 1 (Expr: UnaryOperator), Src: 0 (Expr: DeclRefExpr))
    Use (2 (Decl: ptr), Write)
    OriginFlow (Dest: 2 (Decl: ptr), Src: 1 (Expr: UnaryOperator))
    Use (2 (Decl: ptr), Read)
    OriginFlow (Dest: 3 (Expr: ImplicitCastExpr), Src: 2 (Decl: ptr))
    Expire (0 (Path: x))
    OriginEscapes (3 (Expr: ImplicitCastExpr))
  End of Block
  Block B0:
  End of Block
```

This Expire Fact issues UAR and UAF warnings.

Fixes https://github.com/llvm/llvm-project/issues/162862

0 files changed, 0 insertions, 0 deletions