2 files changed, 43 insertions, 0 deletions
diff --git a/clang/lib/CodeGen/CodeGenAction.cpp b/clang/lib/CodeGen/CodeGenAction.cpp
index da8f372441f..795b3a06f00 100644
--- a/clang/lib/CodeGen/CodeGenAction.cpp
+++ b/clang/lib/CodeGen/CodeGenAction.cpp
@@ -53,6 +53,11 @@ namespace clang {
     Timer LLVMIRGeneration;
     unsigned LLVMIRGenerationRefCount;
 
+    /// True if we've finished generating IR. This prevents us from generating
+    /// additional LLVM IR after emitting output in HandleTranslationUnit. This
+    /// can happen when Clang plugins trigger additional AST deserialization.
+    bool IRGenFinished = false;
+
     std::unique_ptr<CodeGenerator> Gen;
 
     SmallVector<std::pair<unsigned, std::unique_ptr<llvm::Module>>, 4>
@@ -147,6 +152,12 @@ namespace clang {
         LLVMIRGeneration.stopTimer();
     }
 
+    void HandleInterestingDecl(DeclGroupRef D) {
+      // Ignore interesting decls from the AST reader after IRGen is finished.
+      if (!IRGenFinished)
+        HandleTopLevelDecl(D);
+    }
+
     void HandleTranslationUnit(ASTContext &C) override {
       {
         PrettyStackTraceString CrashInfo("Per-file LLVM IR generation");
@@ -163,6 +174,8 @@ namespace clang {
           if (LLVMIRGenerationRefCount == 0)
             LLVMIRGeneration.stopTimer();
         }
+
+	IRGenFinished = true;
       }
 
       // Silently ignore if we weren't initialized for some reason.
diff --git a/clang/test/Frontend/plugin-vs-debug-info.cpp b/clang/test/Frontend/plugin-vs-debug-info.cpp
new file mode 100644
index 00000000000..dceb2f1d5a3
--- /dev/null
+++ b/clang/test/Frontend/plugin-vs-debug-info.cpp
@@ -0,0 +1,30 @@
+// This test uses PrintFunctionNames with -fdelayed-template-parsing because it
+// happens to use a RecursiveASTVisitor that forces deserialization of AST
+// files.
+//
+// RUN: %clang_cc1 -fdelayed-template-parsing -std=c++14 -emit-pch -o %t.pch %s
+// RUN: %clang_cc1 -load %llvmshlibdir/PrintFunctionNames%pluginext \
+// RUN:     -add-plugin print-fns -std=c++14 -include-pch %t.pch %s -emit-llvm \
+// RUN:     -fdelayed-template-parsing -debug-info-kind=limited \
+// RUN:     -o %t.ll 2>&1 | FileCheck --check-prefix=DECLS %s
+// RUN: FileCheck --check-prefix=IR %s < %t.ll
+//
+// REQUIRES: plugins, examples
+
+// DECLS: top-level-decl: "func"
+
+// IR: define {{.*}}void @_Z4funcv()
+
+#ifndef HEADER
+#define HEADER
+
+struct nullopt_t {
+  constexpr explicit nullopt_t(int) {}
+};
+constexpr nullopt_t nullopt(0);
+
+#else
+
+void func() { }
+
+#endif