MIR Parser: Report an error when parsing machine function with an empty body.

This commit adds a new error which is reported when the MIR Parser encounters
a machine function without any machine basic blocks. The machine verifier
expects that the machine functions have at least one MBB, and this error will
prevent machine functions without MBBs from reaching the machine verifier and
crashing with an assertion.

llvm-svn: 241862

1 files changed, 3 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/MIRParser/MIRParser.cpp b/llvm/lib/CodeGen/MIRParser/MIRParser.cpp
index e505ab4baeb..e5ba0322235 100644
--- a/llvm/lib/CodeGen/MIRParser/MIRParser.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MIRParser.cpp
@@ -275,6 +275,9 @@ bool MIRParserImpl::initializeMachineFunction(MachineFunction &MF) {
                    Twine(YamlMBB.ID));
   }
 
+  if (YamlMF.BasicBlocks.empty())
+    return error(Twine("machine function '") + Twine(MF.getName()) +
+                 "' requires at least one machine basic block in its body");
   // Initialize the machine basic blocks after creating them all so that the
   // machine instructions parser can resolve the MBB references.
   unsigned I = 0;