diff --git a/clang-tools-extra/clangd/test/Inputs/symbols-modules/bar.h b/clang-tools-extra/clangd/test/Inputs/symbols-modules/bar.h
new file mode 100644
--- /dev/null
+++ b/clang-tools-extra/clangd/test/Inputs/symbols-modules/bar.h
@@ -0,0 +1,3 @@
+#include "foo.h"
+
+#undef X
diff --git a/clang-tools-extra/clangd/test/Inputs/symbols-modules/compile_commands.json b/clang-tools-extra/clangd/test/Inputs/symbols-modules/compile_commands.json
new file mode 100644
--- /dev/null
+++ b/clang-tools-extra/clangd/test/Inputs/symbols-modules/compile_commands.json
@@ -0,0 +1,5 @@
+[{
+  "directory": "DIRECTORY",
+  "command": "clang -fmodules -Xclang -fmodule-map-file-home-is-cwd -fmodule-map-file=module.map foo.cpp",
+  "file": "DIRECTORY/foo.cpp"
+}]
diff --git a/clang-tools-extra/clangd/test/Inputs/symbols-modules/foo.h b/clang-tools-extra/clangd/test/Inputs/symbols-modules/foo.h
new file mode 100644
--- /dev/null
+++ b/clang-tools-extra/clangd/test/Inputs/symbols-modules/foo.h
@@ -0,0 +1 @@
+#define X 1
diff --git a/clang-tools-extra/clangd/test/Inputs/symbols-modules/module.map b/clang-tools-extra/clangd/test/Inputs/symbols-modules/module.map
new file mode 100644
--- /dev/null
+++ b/clang-tools-extra/clangd/test/Inputs/symbols-modules/module.map
@@ -0,0 +1,4 @@
+module foo {
+  header "foo.h"
+  export *
+}
diff --git a/clang-tools-extra/clangd/test/symbols-modules.test b/clang-tools-extra/clangd/test/symbols-modules.test
new file mode 100644
--- /dev/null
+++ b/clang-tools-extra/clangd/test/symbols-modules.test
@@ -0,0 +1,44 @@
+# Verify that we do not crash and correctly find the definition of a macro that
+# was imported from a module and then #undef-ed in preamble.
+#
+# Copy over the test files and fix the paths.
+# RUN: rm -rf %t
+# RUN: cp -r %S/Inputs/symbols-modules %t
+# RUN: sed -i -e "s|DIRECTORY|%t|" %t/compile_commands.json
+#
+# Fix the paths in this file as well. We will pass this copy to clangd.
+# RUN: sed -e "s|DIRECTORY|%/t|g" %s > %t.test.1
+#
+# RUN: clangd -lit-test < %t.test.1 | FileCheck %s
+{"jsonrpc":"2.0","id":0,"method":"initialize","params":{"processId":123,"rootPath":"clangd","capabilities":{"workspace":{"symbol":{"symbolKind":{"valueSet": [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26]}}}},"trace":"off"}}
+---
+{"jsonrpc":"2.0","method":"textDocument/didOpen","params":{"textDocument":{"uri":"file://DIRECTORY/foo.cpp","languageId":"cpp","version":1,"text":"#include \"bar.h\"\nvoid foo();\n"}}}
+---
+{"jsonrpc":"2.0","id":1,"method":"workspace/symbol","params":{"query":"X"}}
+#      CHECK:  "id": 1,
+# CHECK-NEXT:  "jsonrpc": "2.0",
+# CHECK-NEXT:    "result": [
+# CHECK-NEXT:      {
+# CHECK-NEXT:        "containerName": "",
+# CHECK-NEXT:        "kind": 15,
+# CHECK-NEXT:        "location": {
+# CHECK-NEXT:          "range": {
+# CHECK-NEXT:            "end": {
+# CHECK-NEXT:              "character": {{.*}},
+# CHECK-NEXT:              "line": {{.*}}
+# CHECK-NEXT:            },
+# CHECK-NEXT:            "start": {
+# CHECK-NEXT:              "character": {{.*}},
+# CHECK-NEXT:              "line": {{.*}}
+# CHECK-NEXT:            }
+# CHECK-NEXT:          },
+# CHECK-NEXT:          "uri": "file://{{.*}}/foo.h"
+# CHECK-NEXT:        },
+# CHECK-NEXT:        "name": "X"
+# CHECK-NEXT:      }
+# CHECK-NEXT:    ]
+# CHECK-NEXT:}
+---
+{"jsonrpc":"2.0","id":3,"method":"shutdown"}
+---
+{"jsonrpc":"2.0","method":"exit"}
diff --git a/clang/include/clang/Lex/Preprocessor.h b/clang/include/clang/Lex/Preprocessor.h
--- a/clang/include/clang/Lex/Preprocessor.h
+++ b/clang/include/clang/Lex/Preprocessor.h
@@ -1115,6 +1115,30 @@
     return nullptr;
   }
 
+  // Returns MacroInfo for the latest definition of II. It could possibly be
+  // imported from a module (thus not accesible via getMacroInfo()), whether
+  // it's active or not.
+  MacroInfo *getMacroInfoForLatestDefinition(const IdentifierInfo *II) {
+    if (!II->hasMacroDefinition())
+      return nullptr;
+    if (auto *MI = getMacroInfo(II))
+      return MI;
+    MacroState &S = CurSubmoduleState->Macros[II];
+    auto ActiveModuleMacros = S.getActiveModuleMacros(*this, II);
+    for (auto MM = ActiveModuleMacros.rbegin(); MM != ActiveModuleMacros.rend();
+         MM++) {
+      if (auto *MI = (*MM)->getMacroInfo())
+        return MI;
+    }
+    auto OverridenMacros = S.getOverriddenMacros();
+    for (auto MM = OverridenMacros.rbegin(); MM != OverridenMacros.rend();
+         MM++) {
+      if (auto *MI = (*MM)->getMacroInfo())
+        return MI;
+    }
+    return nullptr;
+  }
+
   /// Given an identifier, return the latest non-imported macro
   /// directive for that identifier.
   ///
diff --git a/clang/lib/Index/IndexingAction.cpp b/clang/lib/Index/IndexingAction.cpp
--- a/clang/lib/Index/IndexingAction.cpp
+++ b/clang/lib/Index/IndexingAction.cpp
@@ -147,14 +147,23 @@
   Unit.visitLocalTopLevelDecls(&IndexCtx, topLevelDeclVisitor);
 }
 
-static void indexPreprocessorMacros(const Preprocessor &PP,
+static void indexPreprocessorMacros(Preprocessor &PP,
                                     IndexDataConsumer &DataConsumer) {
-  for (const auto &M : PP.macros())
-    if (MacroDirective *MD = M.second.getLatest())
+  for (const auto &M : PP.macros()) {
+    if (MacroDirective *MD = M.second.getLatest()) {
+      auto *MI = MD->getMacroInfo();
+      if (!MI) {
+        // It is possible for MI to be nullptr if we our translation unit had
+        // only #undef of a macro defined in a module. In that case, dig deeper
+        // and use the definition from the module to yield the same indexing
+        // result whether we are using modules or not.
+        MI = PP.getMacroInfoForLatestDefinition(M.first);
+      }
       DataConsumer.handleMacroOccurrence(
-          M.first, MD->getMacroInfo(),
-          static_cast<unsigned>(index::SymbolRole::Definition),
+          M.first, MI, static_cast<unsigned>(index::SymbolRole::Definition),
           MD->getLocation());
+    }
+  }
 }
 
 void index::indexASTUnit(ASTUnit &Unit, IndexDataConsumer &DataConsumer,