[IR] Disallow recursive types (#114799)

StructType::setBody is the only mechanism that can potentially create
recursion in the type system. Add a runtime check that it is not
actually used to create recursion.

If the check fails, report an error from LLParser, BitcodeReader and
IRLinker. In all other cases assert that the check succeeds.

In future StructType::setBody will be removed in favor of specifying the
body when the type is created, so any performance hit from this runtime
check will be temporary.

1 files changed, 2 insertions, 1 deletions

diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index 446c98c8cecd..3e82aa7188bd 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -2659,7 +2659,8 @@ Error BitcodeReader::parseTypeTableBody() {
       }
       if (EltTys.size() != Record.size()-1)
         return error("Invalid named struct record");
-      Res->setBody(EltTys, Record[0]);
+      if (auto E = Res->setBodyOrError(EltTys, Record[0]))
+        return E;
       ContainedIDs.append(Record.begin() + 1, Record.end());
       ResultTy = Res;
       break;