From 898925c94fef9c5822b2910024cf716bf295b9da Mon Sep 17 00:00:00 2001
From: Bob Haarman <llvm@inglorion.net>
Date: Tue, 24 Nov 2020 21:40:26 +0000
Subject: [PATCH] clang: disable assert for DK_Linker diagnostics

CodeGenAction.cpp contained an assert requiring that CurLinkModule is
set to a non-null value for DK_Linker diagnostics. The intent here to
always report the module name when we are reporting such diagnostics.
In practice, CurLinkModule is not always set, so this assert can
trigger. When it does, the compiler crashes and we get neither the
module name nor the diagnostic. This happens even for warnings that
have been suppressed with -Wno-*, so we are failing builds that
otherwise would have succeeded. Long-term, we probably want to ensure
that the module name is always provided, but short term, it seems
strictly better to report the diagnostic without the module name
than to crash the compiler. This change removes the assert and
modifies the code to handle the case where CurLinkModule is not
set.
---
 clang/lib/CodeGen/CodeGenAction.cpp | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/clang/lib/CodeGen/CodeGenAction.cpp b/clang/lib/CodeGen/CodeGenAction.cpp
index 1e935bbeeca..7590c9b2c29 100644
--- a/clang/lib/CodeGen/CodeGenAction.cpp
+++ b/clang/lib/CodeGen/CodeGenAction.cpp
@@ -794,7 +794,6 @@ void BackendConsumer::DiagnosticHandlerImpl(const DiagnosticInfo &DI) {
     ComputeDiagID(Severity, backend_frame_larger_than, DiagID);
     break;
   case DK_Linker:
-    assert(CurLinkModule);
     // FIXME: stop eating the warnings and notes.
     if (Severity != DS_Error)
       return;
@@ -861,8 +860,11 @@ void BackendConsumer::DiagnosticHandlerImpl(const DiagnosticInfo &DI) {
   }
 
   if (DiagID == diag::err_fe_cannot_link_module) {
-    Diags.Report(diag::err_fe_cannot_link_module)
-        << CurLinkModule->getModuleIdentifier() << MsgStorage;
+    if (CurLinkModule)
+      Diags.Report(DiagID)
+          << CurLinkModule->getModuleIdentifier() << MsgStorage;
+    else
+      Diags.Report(DiagID) << MsgStorage;
     return;
   }
 
-- 
2.29.2.454.gaff20da3a2-goog