Index: lib/StaticAnalyzer/Core/CMakeLists.txt
===================================================================
--- lib/StaticAnalyzer/Core/CMakeLists.txt
+++ lib/StaticAnalyzer/Core/CMakeLists.txt
@@ -53,6 +53,7 @@
   clangAnalysis
   clangBasic
   clangCrossTU
+  clangFrontend
   clangLex
   clangRewrite
   )
Index: lib/StaticAnalyzer/Core/PlistDiagnostics.cpp
===================================================================
--- lib/StaticAnalyzer/Core/PlistDiagnostics.cpp
+++ lib/StaticAnalyzer/Core/PlistDiagnostics.cpp
@@ -15,6 +15,7 @@
 #include "clang/Basic/SourceManager.h"
 #include "clang/Basic/Version.h"
 #include "clang/CrossTU/CrossTranslationUnit.h"
+#include "clang/Frontend/ASTUnit.h"
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Lex/TokenConcatenation.h"
 #include "clang/Rewrite/Core/HTMLRewrite.h"
@@ -75,12 +76,14 @@
   const FIDMap& FM;
   AnalyzerOptions &AnOpts;
   const Preprocessor &PP;
+  const cross_tu::CrossTranslationUnitContext &CTU;
   llvm::SmallVector<const PathDiagnosticMacroPiece *, 0> MacroPieces;
 
 public:
   PlistPrinter(const FIDMap& FM, AnalyzerOptions &AnOpts,
-               const Preprocessor &PP)
-    : FM(FM), AnOpts(AnOpts), PP(PP) {
+               const Preprocessor &PP,
+               const cross_tu::CrossTranslationUnitContext &CTU)
+    : FM(FM), AnOpts(AnOpts), PP(PP), CTU(CTU) {
   }
 
   void ReportDiag(raw_ostream &o, const PathDiagnosticPiece& P) {
@@ -162,8 +165,8 @@
 } // end of anonymous namespace
 
 static void printBugPath(llvm::raw_ostream &o, const FIDMap& FM,
-                         AnalyzerOptions &AnOpts,
-                         const Preprocessor &PP,
+                         AnalyzerOptions &AnOpts, const Preprocessor &PP,
+                         const cross_tu::CrossTranslationUnitContext &CTU,
                          const PathPieces &Path);
 
 /// Print coverage information to output stream {@code o}.
@@ -174,8 +177,9 @@
                           FIDMap &FM,
                           llvm::raw_fd_ostream &o);
 
-static ExpansionInfo getExpandedMacro(SourceLocation MacroLoc,
-                                      const Preprocessor &PP);
+static ExpansionInfo
+getExpandedMacro(SourceLocation MacroLoc, const Preprocessor &PP,
+                 const cross_tu::CrossTranslationUnitContext &CTU);
 
 //===----------------------------------------------------------------------===//
 // Methods of PlistPrinter.
@@ -349,7 +353,7 @@
 
   for (const PathDiagnosticMacroPiece *P : MacroPieces) {
     const SourceManager &SM = PP.getSourceManager();
-    ExpansionInfo EI = getExpandedMacro(P->getLocation().asLocation(), PP);
+    ExpansionInfo EI = getExpandedMacro(P->getLocation().asLocation(), PP, CTU);
 
     Indent(o, indent) << "<dict>\n";
     ++indent;
@@ -471,10 +475,10 @@
 }
 
 static void printBugPath(llvm::raw_ostream &o, const FIDMap& FM,
-                         AnalyzerOptions &AnOpts,
-                         const Preprocessor &PP,
+                         AnalyzerOptions &AnOpts, const Preprocessor &PP,
+                         const cross_tu::CrossTranslationUnitContext &CTU,
                          const PathPieces &Path) {
-  PlistPrinter Printer(FM, AnOpts, PP);
+  PlistPrinter Printer(FM, AnOpts, PP, CTU);
   assert(std::is_partitioned(
            Path.begin(), Path.end(),
            [](const std::shared_ptr<PathDiagnosticPiece> &E)
@@ -619,7 +623,7 @@
     o << "  <dict>\n";
 
     const PathDiagnostic *D = *DI;
-    printBugPath(o, FM, AnOpts, PP, D->path);
+    printBugPath(o, FM, AnOpts, PP, CTU, D->path);
 
     // Output the bug type and bug category.
     o << "   <key>description</key>";
@@ -872,17 +876,23 @@
 // Definitions of helper functions and methods for expanding macros.
 //===----------------------------------------------------------------------===//
 
-static ExpansionInfo getExpandedMacro(SourceLocation MacroLoc,
-                                      const Preprocessor &PP) {
+static ExpansionInfo
+getExpandedMacro(SourceLocation MacroLoc, const Preprocessor &PP,
+                 const cross_tu::CrossTranslationUnitContext &CTU) {
+
+  const Preprocessor *PPToUse = &PP;
+  if (auto LocAndUnit = CTU.getImportedFromSourceLocation(MacroLoc)) {
+    MacroLoc = LocAndUnit->first;
+    PPToUse = &LocAndUnit->second->getPreprocessor();
+  }
 
   llvm::SmallString<200> ExpansionBuf;
   llvm::raw_svector_ostream OS(ExpansionBuf);
-  TokenPrinter Printer(OS, PP);
+  TokenPrinter Printer(OS, *PPToUse);
   llvm::SmallPtrSet<IdentifierInfo*, 8> AlreadyProcessedTokens;
 
-  std::string MacroName =
-            getMacroNameAndPrintExpansion(Printer, MacroLoc, PP, MacroArgMap{},
-                                         AlreadyProcessedTokens);
+  std::string MacroName = getMacroNameAndPrintExpansion(
+      Printer, MacroLoc, *PPToUse, MacroArgMap{}, AlreadyProcessedTokens);
   return { MacroName, OS.str() };
 }
 
Index: test/Analysis/Inputs/plist-macros-ctu.h
===================================================================
--- /dev/null
+++ test/Analysis/Inputs/plist-macros-ctu.h
@@ -0,0 +1,4 @@
+#define M_H *A = (int *)0
+void F_H(int **A) {
+  M_H;
+}
Index: test/Analysis/Inputs/plist-macros-ctu.c
===================================================================
--- /dev/null
+++ test/Analysis/Inputs/plist-macros-ctu.c
@@ -0,0 +1,21 @@
+
+#include "plist-macros-ctu.h"
+
+#define M *X = (int *)0
+
+void F1(int **X) {
+  M;
+}
+
+#undef M
+#define M *Y = (int *)0
+
+void F2(int **Y) {
+  M;
+}
+
+#define M1 *Z = (int *)0
+
+void F3(int **Z) {
+  M1;
+}
Index: test/Analysis/Inputs/plist-macros-with-expansion-ctu.c.externalDefMap.txt
===================================================================
--- /dev/null
+++ test/Analysis/Inputs/plist-macros-with-expansion-ctu.c.externalDefMap.txt
@@ -0,0 +1,4 @@
+c:@F@F1 plist-macros-ctu.c.ast
+c:@F@F2 plist-macros-ctu.c.ast
+c:@F@F3 plist-macros-ctu.c.ast
+c:@F@F_H plist-macros-ctu.c.ast
Index: test/Analysis/plist-macros-with-expansion-ctu.c
===================================================================
--- /dev/null
+++ test/Analysis/plist-macros-with-expansion-ctu.c
@@ -0,0 +1,80 @@
+// RUN: rm -rf %t && mkdir %t
+// RUN: mkdir -p %t/ctudir
+// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu \
+// RUN:   -emit-pch -o %t/ctudir/plist-macros-ctu.c.ast %S/Inputs/plist-macros-ctu.c
+// RUN: cp %S/Inputs/plist-macros-with-expansion-ctu.c.externalDefMap.txt %t/ctudir/externalDefMap.txt
+
+// RUN: %clang_analyze_cc1 -analyzer-checker=core \
+// RUN:   -analyzer-config experimental-enable-naive-ctu-analysis=true \
+// RUN:   -analyzer-config ctu-dir=%t/ctudir \
+// RUN:   -analyzer-config expand-macros=true \
+// RUN:   -analyzer-output=plist-multi-file -o %t.plist -verify %s
+
+// Check the macro expansions from the plist output here, to make the test more
+// understandable.
+//   RUN: FileCheck --input-file=%t.plist %s
+
+extern void F1(int **);
+extern void F2(int **);
+extern void F3(int **);
+extern void F_H(int **);
+
+void test0() {
+  int *X;
+  F3(&X);
+  *X = 1; // expected-warning{{Dereference of null pointer}}
+}
+// CHECK: <key>name</key><string>M1</string>
+// CHECK-NEXT: <key>expansion</key><string>*Z = (int *)0</string>
+
+
+void test1() {
+  int *X;
+  F1(&X);
+  *X = 1; // expected-warning{{Dereference of null pointer}}
+}
+// CHECK: <key>name</key><string>M</string>
+// CHECK-NEXT: <key>expansion</key><string>*X = (int *)0</string>
+
+void test2() {
+  int *X;
+  F2(&X);
+  *X = 1; // expected-warning{{Dereference of null pointer}}
+}
+// CHECK: <key>name</key><string>M</string>
+// CHECK-NEXT: <key>expansion</key><string>*Y = (int *)0</string>
+
+#define M F1(&X)
+
+void test3() {
+  int *X;
+  M;
+  *X = 1; // expected-warning{{Dereference of null pointer}}
+}
+// CHECK: <key>name</key><string>M</string>
+// CHECK-NEXT: <key>expansion</key><string>F1(&amp;X)</string>
+// CHECK: <key>name</key><string>M</string>
+// CHECK-NEXT: <key>expansion</key><string>*X = (int *)0</string>
+
+#undef M
+#define M F2(&X)
+
+void test4() {
+  int *X;
+  M;
+  *X = 1; // expected-warning{{Dereference of null pointer}}
+}
+
+// CHECK: <key>name</key><string>M</string>
+// CHECK-NEXT: <key>expansion</key><string>F2(&amp;X)</string>
+// CHECK: <key>name</key><string>M</string>
+// CHECK-NEXT: <key>expansion</key><string>*Y = (int *)0</string>
+
+void test_h() {
+  int *X;
+  F_H(&X);
+  *X = 1; // expected-warning{{Dereference of null pointer}}
+}
+
+// CHECK: <key>name</key><string>M_H</string>
+// CHECK-NEXT: <key>expansion</key><string>*A = (int *)0</string>