[clang] [dataflow] Fix crash when InitListExpr is not a prvalue (PR #80970)

[Paul Semel via cfe-commits]

https://github.com/paulsemel created https://github.com/llvm/llvm-project/pull/80970

None

>From e56ced76e19d57a020030ab41a125012460d08d7 Mon Sep 17 00:00:00 2001
From: Paul Semel <semelpaul at gmail.com>
Date: Wed, 7 Feb 2024 10:26:23 +0000
Subject: [PATCH] [dataflow] Fix crash when InitListExpr is not a prvalue

---
 clang/lib/Analysis/FlowSensitive/Transfer.cpp      |  6 ++++++
 .../Analysis/FlowSensitive/TransferTest.cpp        | 14 ++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/clang/lib/Analysis/FlowSensitive/Transfer.cpp b/clang/lib/Analysis/FlowSensitive/Transfer.cpp
index bb3aec763c29c..dc0f1bd6dcc29 100644
--- a/clang/lib/Analysis/FlowSensitive/Transfer.cpp
+++ b/clang/lib/Analysis/FlowSensitive/Transfer.cpp
@@ -648,6 +648,12 @@ class TransferVisitor : public ConstStmtVisitor<TransferVisitor> {
     QualType Type = S->getType();
 
     if (!Type->isStructureOrClassType()) {
+      // It is possible that InitListExpr is not a prvalue, in which case
+      // `setValue` will fail. In this case, we can just let the next
+      // transfer function handle the value creation.
+      if (!S->isPRValue())
+        return;
+
       if (auto *Val = Env.createValue(Type))
         Env.setValue(*S, *Val);
 
diff --git a/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp b/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp
index 8bbb04024dcce..74e6f1abfa4ba 100644
--- a/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp
+++ b/clang/unittests/Analysis/FlowSensitive/TransferTest.cpp
@@ -2313,6 +2313,20 @@ TEST(TransferTest, AssignmentOperatorWithInitAndInheritance) {
          ASTContext &ASTCtx) {});
 }
 
+TEST(TransferTest, InitListExprAsXValue) {
+  // This is a crash repro.
+  std::string Code = R"(
+    void target() {
+      auto&& test{false};
+      // [[p]]
+    }
+  )";
+  runDataflow(
+      Code,
+      [](const llvm::StringMap<DataflowAnalysisState<NoopLattice>> &Results,
+         ASTContext &ASTCtx) {});
+}
+
 TEST(TransferTest, CopyConstructor) {
   std::string Code = R"(
     struct A {