[llvm-branch-commits] [clang] [LifetimeSafety][NFC] Add field-labeled child edges to OriginNode and generalize subtree walks (PR #201510)

[Utkarsh Saxena via llvm-branch-commits]

================
@@ -66,47 +66,88 @@ struct Origin {
   }
 };
 
-/// A list of origins representing levels of indirection for pointer-like types.
+/// A tree of origins representing the structure of a pointer-like or
+/// record type.
 ///
-/// Each node in the list contains an OriginID representing a level of
-/// indirection. The list structure captures the multi-level nature of
-/// pointer and reference types in the lifetime analysis.
+/// Each node carries an OriginID and is connected to children via labeled
+/// edges: either a pointee edge (one level of pointer/reference indirection)
+/// or a field edge (a named field of a record). Pointer-like types form a
+/// pointee chain; record types fan out via field edges.
 ///
 /// Examples:
-///   - For `int& x`, the list has size 2:
-///     * Outer: origin for the reference storage itself (the lvalue `x`)
-///     * Inner: origin for what `x` refers to
+///   - For `int& x`, the chain has length 2:
+///       Outer: the reference storage itself (the lvalue `x`)
+///        +-pointee-> Inner: what `x` refers to
 ///
-///   - For `int* p`, the list has size 2:
-///     * Outer: origin for the pointer variable `p`
-///     * Inner: origin for what `p` points to
+///   - For `int* p`, the chain has length 2:
+///       Outer: the pointer variable `p`
+///        +-pointee-> Inner: what `p` points to
 ///
-///   - For `View v` (where View is gsl::Pointer), the list has size 2:
-///     * Outer: origin for the view object itself
-///     * Inner: origin for what the view refers to
+///   - For `View v` (View is gsl::Pointer), the chain has length 2:
+///       Outer: the view object itself
+///        +-pointee-> Inner: what the view refers to
 ///
-///   - For `int** pp`, the list has size 3:
-///     * Outer: origin for `pp` itself
-///     * Inner: origin for `*pp` (what `pp` points to)
-///     * Inner->Inner: origin for `**pp` (what `*pp` points to)
+///   - For `int** pp`, the chain has length 3:
+///       Outer: `pp` itself
+///        +-pointee-> Inner: `*pp` (what `pp` points to)
+///           +-pointee-> Inner->Inner: `**pp` (what `*pp` points to)
 ///
-/// The list structure enables the analysis to track how loans flow through
-/// different levels of indirection when assignments and dereferences occur.
+///   - For `struct S { View a; Inner b; }` (with `struct Inner { View c; }`),
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usx95 wrote:

You are right. This seems to be a mistake.
There is only one origin: https://godbolt.org/z/exETYxnq3

https://github.com/llvm/llvm-project/pull/201510