[clang] [Serialization] Clear moved-from deque to ensure valid state post-move (PR #97221)

[via cfe-commits]

https://github.com/smanna12 created https://github.com/llvm/llvm-project/pull/97221

This patch addresses a use-after-move issue, reported by static analyzer tool, by clearing the `PotentiallyInterestingDecls` deque after it has been moved to `MaybeInterestingDecls`.

The fix ensures that the subsequent assert statement correctly checks for an empty state, preventing any undefined behavior in ASTReader::PassInterestingDeclsToConsumer().

>From fb5f36ee15bbeaf0d6d181dcf51c2847fc8babc8 Mon Sep 17 00:00:00 2001
From: "Manna, Soumi" <soumi.manna at intel.com>
Date: Sun, 30 Jun 2024 09:05:12 -0700
Subject: [PATCH] [Serialization] Clear moved-from deque to ensure valid state
 post-move

This patch addresses a use-after-move issue, reported by static analyzer
tool, by clearing the `PotentiallyInterestingDecls` deque after it has been
moved to `MaybeInterestingDecls`.

The fix ensures that the subsequent assert statement correctly checks for an
empty state, preventing any undefined behavior in ASTReader::PassInterestingDeclsToConsumer().
---
 clang/lib/Serialization/ASTReaderDecl.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index 6afb18f932e72..cf3737c5a501d 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -4215,6 +4215,7 @@ void ASTReader::PassInterestingDeclsToConsumer() {
   };
   std::deque<Decl *> MaybeInterestingDecls =
       std::move(PotentiallyInterestingDecls);
+  PotentiallyInterestingDecls.clear();
   assert(PotentiallyInterestingDecls.empty());
   while (!MaybeInterestingDecls.empty()) {
     Decl *D = MaybeInterestingDecls.front();