================
@@ -346,6 +352,39 @@ class CompoundVal : public NonLoc {
static bool classof(SVal V) { return V.getKind() == CompoundValKind; }
};
+/// The simplest example of a concrete compound value is nonloc::CompoundVal,
+/// which represents a concrete r-value of an initializer-list or a string.
+/// Internally, it contains an llvm::ImmutableList of SVal's stored inside the
+/// literal.
+///
+/// However, there is another compound value used in the analyzer, which
appears
+/// much more often during analysis, which is nonloc::LazyCompoundVal. This
+/// value is an r-value that represents a snapshot of any structure "as a
whole"
+/// at a given moment during the analysis. Such value is already quite far from
+/// being re- ferred to as "concrete", as many fields inside it would be
unknown
+/// or symbolic. nonloc::LazyCompoundVal operates by storing two things:
+/// * a reference to the TypedValueRegion being snapshotted (yes, it is
always
+/// typed), and also
+/// * a copy of the whole Store object, obtained from the ProgramState in
+/// which it was created.
+///
+/// Essentially, nonloc::LazyCompoundVal is a performance optimization for the
+/// analyzer. Because Store is immutable, creating a nonloc::LazyCompoundVal is
+/// a very cheap operation. Note that the Store contains all region bindings in
+/// the program state, not only related to the region. Later, if necessary,
such
+/// value can be unpacked -- eg. when it is assigned to another variable.
+///
+/// Source: https://github.com/haoNoQ/clang-analyzer-guide, v0.1, section
5.3.2.
----------------
steakhal wrote:
```suggestion
```
https://github.com/llvm/llvm-project/pull/97407
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