[PATCH] D146538: [analyzer] Fix crashing getSValFromInitListExpr for nested initlists

[Balázs Benics via Phabricator via cfe-commits]

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In the following example, we will end up hitting the `llvm_unreachable()`:
https://godbolt.org/z/5sccc95Ec

  enum class E {};
  const E glob[] = {{}};
  void initlistWithinInitlist() {
    clang_analyzer_dump(glob[0]); // crashes at loading from `glob[0]`
  }

We should just return `std::nullopt` instead for these cases. It's better than crashing.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D146538

Files:
  clang/lib/StaticAnalyzer/Core/RegionStore.cpp
  clang/test/Analysis/initialization.cpp


Index: clang/test/Analysis/initialization.cpp
===================================================================
--- clang/test/Analysis/initialization.cpp
+++ clang/test/Analysis/initialization.cpp
@@ -249,3 +249,10 @@
   clang_analyzer_eval(glob_arr9[1][2] == 7); // expected-warning{{TRUE}}
   clang_analyzer_eval(glob_arr9[1][3] == 0); // expected-warning{{TRUE}}
 }
+
+enum class E {};
+const E glob[] = {{}};
+void initlistWithinInitlist() {
+  // no-crash
+  clang_analyzer_dump(glob[0]); // expected-warning-re {{reg_${{[0-9]+}}<enum E Element{glob,0 S64b,enum E}>}}
+}
Index: clang/lib/StaticAnalyzer/Core/RegionStore.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Core/RegionStore.cpp
+++ clang/lib/StaticAnalyzer/Core/RegionStore.cpp
@@ -1849,8 +1849,12 @@
     // Go to the nested initializer list.
     ILE = IL;
   }
-  llvm_unreachable(
-      "Unhandled InitListExpr sub-expressions or invalid offsets.");
+
+  assert(ILE);
+
+  // FIXME: Unhandeled InitListExpr sub-expression, possibly constructing an
+  //        enum?
+  return std::nullopt;
 }
 
 /// Returns an SVal, if possible, for the specified position in a string


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