================
@@ -1726,20 +1725,29 @@ class BuildLockset : public
ConstStmtVisitor<BuildLockset> {
FactSet FSet;
// The fact set for the function on exit.
const FactSet &FunctionExitFSet;
+ // Use `LVarCtx` to keep track of the context at each program point, which
+ // will be used to translate DREs (by `SExprBuilder::translateDeclRefExpr`)
+ // to their canonical definitions:
----------------
aaronpuchert wrote:
There is already [an
explanation](https://github.com/llvm/llvm-project/blob/llvmorg-23-init/clang/lib/Analysis/ThreadSafety.cpp#L392-L404)
of the mechanism on `LocalVariableMap`:
```c++
// A LocalVariableMap maintains a map from local variables to their currently
// valid definitions. It provides SSA-like functionality when traversing the
// CFG. Like SSA, each definition or assignment to a variable is assigned a
// unique name (an integer), which acts as the SSA name for that definition.
// The total set of names is shared among all CFG basic blocks.
// Unlike SSA, we do not rewrite expressions to replace local variables declrefs
// with their SSA-names. Instead, we compute a Context for each point in the
// code, which maps local variables to the appropriate SSA-name. This map
// changes with each assignment.
//
// The map is computed in a single pass over the CFG. Subsequent analyses can
// then query the map to find the appropriate Context for a statement, and use
// that Context to look up the definitions of variables.
```
I think that covers the same points.
https://github.com/llvm/llvm-project/pull/178952
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