(Trivial) TargetPassConfig: assert when TargetMachine has no MCAsmInfo

Summary:
This is a pretty trivial, but I thought it was worth just checking that nobody feels it's completely the wrong thing to be doing.

The motivation is that when starting a new backend, you often start with a minimal stub, pretty much just FooTargetMachine and FooTargetInfo. Once that's built, you might naturally try `llc -march=foo myinput.ll` and it seems more developer-friendly if this ends up asserting due to the lack of MCAsmInfo with an informative message rather than just segfaulting.

Reviewers: MatzeB, chandlerc

Subscribers: bogner, llvm-commits

Differential Revision: https://reviews.llvm.org/D23443

llvm-svn: 279061

1 files changed, 3 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/TargetPassConfig.cpp b/llvm/lib/CodeGen/TargetPassConfig.cpp
index 5b29273cfd0..94ee30264dd 100644
--- a/llvm/lib/CodeGen/TargetPassConfig.cpp
+++ b/llvm/lib/CodeGen/TargetPassConfig.cpp
@@ -474,7 +474,9 @@ void TargetPassConfig::addIRPasses() {
 /// Turn exception handling constructs into something the code generators can
 /// handle.
 void TargetPassConfig::addPassesToHandleExceptions() {
-  switch (TM->getMCAsmInfo()->getExceptionHandlingType()) {
+  const MCAsmInfo *MCAI = TM->getMCAsmInfo();
+  assert(MCAI && "No MCAsmInfo");
+  switch (MCAI->getExceptionHandlingType()) {
   case ExceptionHandling::SjLj:
     // SjLj piggy-backs on dwarf for this bit. The cleanups done apply to both
     // Dwarf EH prepare needs to be run after SjLj prepare. Otherwise,