[clang] [clang][dataflow] Collect local variables referenced within a functio… (PR #104459)

[Samira Bazuzi via cfe-commits]

https://github.com/bazuzi created https://github.com/llvm/llvm-project/pull/104459

…n/statement.

We don't need these for the same in-tree purposes as the other sets, i.e. for making sure we model these Decls that are declared outside the function, but we have an out-of-tree use for these sets that would benefit from this simple addition and would avoid duplicating so much of this code.

>From 5aaa8c5e65b59b0f21775811f48dec350ae210c7 Mon Sep 17 00:00:00 2001
From: Samira Bazuzi <bazuzi at google.com>
Date: Thu, 15 Aug 2024 11:11:30 -0400
Subject: [PATCH] [clang][dataflow] Collect local variables referenced within a
 function/statement.

---
 clang/include/clang/Analysis/FlowSensitive/ASTOps.h | 3 +++
 clang/lib/Analysis/FlowSensitive/ASTOps.cpp         | 9 +++++++++
 2 files changed, 12 insertions(+)

diff --git a/clang/include/clang/Analysis/FlowSensitive/ASTOps.h b/clang/include/clang/Analysis/FlowSensitive/ASTOps.h
index f9c923a36ad229..ec4d041254877f 100644
--- a/clang/include/clang/Analysis/FlowSensitive/ASTOps.h
+++ b/clang/include/clang/Analysis/FlowSensitive/ASTOps.h
@@ -139,6 +139,9 @@ struct ReferencedDecls {
   /// All variables with static storage duration, notably including static
   /// member variables and static variables declared within a function.
   llvm::DenseSet<const VarDecl *> Globals;
+  /// Local variables, not including parameters or static variables declared
+  /// within a function.
+  llvm::DenseSet<const VarDecl *> Locals;
   /// Free functions and member functions which are referenced (but not
   /// necessarily called).
   llvm::DenseSet<const FunctionDecl *> Functions;
diff --git a/clang/lib/Analysis/FlowSensitive/ASTOps.cpp b/clang/lib/Analysis/FlowSensitive/ASTOps.cpp
index 27d42a7b508562..fdba139628d8ff 100644
--- a/clang/lib/Analysis/FlowSensitive/ASTOps.cpp
+++ b/clang/lib/Analysis/FlowSensitive/ASTOps.cpp
@@ -170,6 +170,13 @@ static void insertIfGlobal(const Decl &D,
       Globals.insert(V);
 }
 
+static void insertIfLocal(const Decl &D,
+                          llvm::DenseSet<const VarDecl *> &Locals) {
+  if (auto *V = dyn_cast<VarDecl>(&D))
+    if (V->hasLocalStorage() && !isa<ParmVarDecl>(V))
+      Locals.insert(V);
+}
+
 static void insertIfFunction(const Decl &D,
                              llvm::DenseSet<const FunctionDecl *> &Funcs) {
   if (auto *FD = dyn_cast<FunctionDecl>(&D))
@@ -220,12 +227,14 @@ class ReferencedDeclsVisitor
 
   bool VisitDecl(Decl *D) {
     insertIfGlobal(*D, Referenced.Globals);
+    insertIfLocal(*D, Referenced.Locals);
     insertIfFunction(*D, Referenced.Functions);
     return true;
   }
 
   bool VisitDeclRefExpr(DeclRefExpr *E) {
     insertIfGlobal(*E->getDecl(), Referenced.Globals);
+    insertIfLocal(*E->getDecl(), Referenced.Locals);
     insertIfFunction(*E->getDecl(), Referenced.Functions);
     return true;
   }