From 9b4250d309ee785e1e33f3573bd4560c2d92003f Mon Sep 17 00:00:00 2001
From: "Duncan P. N. Exon Smith" <dexonsmith@apple.com>
Date: Mon, 16 Mar 2015 21:23:56 +0000
Subject: [PATCH] Verifier: Don't call debug info verifier if the module is
 broken

If `Verifier` has already found a failure, don't call
`DebugInfoVerifier`.  The latter sometimes crashes in `DebugInfoFinder`
when the former would give a nice message.  The only two cases I found
it crashing are explicit verifier tests I've added:

  - test/Verifier/llvm.dbg.declare-expression.ll
  - test/Verifier/llvm.dbg.value-expression.ll

However, I assume frontends with bugs will create invalid IR as well.

IMO, the `DebugInfoVerifier` should never crash (instead, it should fail
to verify), but subtleties like that will be easier to work out once
it's enabled again.

This is part of PR22777.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232418 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/IR/Verifier.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/lib/IR/Verifier.cpp b/lib/IR/Verifier.cpp
index 5e2186d12a6..13da05ee302 100644
--- a/lib/IR/Verifier.cpp
+++ b/lib/IR/Verifier.cpp
@@ -3113,8 +3113,13 @@ bool llvm::verifyModule(const Module &M, raw_ostream *OS) {
 
   // Note that this function's return value is inverted from what you would
   // expect of a function called "verify".
+  if (!V.verify(M) || Broken)
+    return true;
+
+  // Run the debug info verifier only if the regular verifier succeeds, since
+  // sometimes checks that have already failed will cause crashes here.
   DebugInfoVerifier DIV(OS ? *OS : NullStr);
-  return !V.verify(M) || !DIV.verify(M) || Broken;
+  return !DIV.verify(M);
 }
 
 namespace {