Try loading msdiaNNN.dll if CoCreateInstance(CLSID_DiaSource) fails

src/common/windows/pdb_source_line_writer.cc

Index: src/common/windows/pdb_source_line_writer.cc
diff --git a/src/common/windows/pdb_source_line_writer.cc b/src/common/windows/pdb_source_line_writer.cc
index 3c3401d281ec816b775645437b558c3fcbb06d39..f0edb721c07e86bd9658a984be55e6bf23749dbe 100644
--- a/src/common/windows/pdb_source_line_writer.cc
+++ b/src/common/windows/pdb_source_line_writer.cc
@@ -33,6 +33,7 @@
 #include <winnt.h>
 #include <atlbase.h>
 #include <dia2.h>
+#include <diacreate.h>
 #include <ImageHlp.h>
 #include <stdio.h>
 
@@ -121,6 +122,40 @@ class AutoImage {
   PLOADED_IMAGE img_;
 };
 
+bool CreateDiaDataSourceInstance(CComPtr<IDiaDataSource> &data_source) {
+  if (SUCCEEDED(data_source.CoCreateInstance(CLSID_DiaSource))) {
+    return true;
+  }
+
+  class DECLSPEC_UUID("B86AE24D-BF2F-4ac9-B5A2-34B14E4CE11D") DiaSource100;
+  class DECLSPEC_UUID("761D3BCD-1304-41D5-94E8-EAC54E4AC172") DiaSource110;
+  class DECLSPEC_UUID("3BFCEA48-620F-4B6B-81F7-B9AF75454C7D") DiaSource120;
+  class DECLSPEC_UUID("E6756135-1E65-4D17-8576-610761398C3C") DiaSource140;
+
+  // If the CoCreateInstance call above failed, msdia*.dll is not registered.
+  // We can try loading the DLL corresponding to the #included DIA SDK, but
+  // the DIA headers don't provide a version. Lets try to figure out which DIA
+  // version we're compiling against by comparing CLSIDs.
+  const wchar_t *msdia_dll = nullptr;
+  if (CLSID_DiaSource == _uuidof(DiaSource100)) {
+    msdia_dll = L"msdia100.dll";
+  } else if (CLSID_DiaSource == _uuidof(DiaSource110)) {
+    msdia_dll = L"msdia110.dll";
+  } else if (CLSID_DiaSource == _uuidof(DiaSource120)) {
+    msdia_dll = L"msdia120.dll";
+  } else if (CLSID_DiaSource == _uuidof(DiaSource140)) {
+    msdia_dll = L"msdia140.dll";
+  }
+
+  if (msdia_dll &&
+      SUCCEEDED(NoRegCoCreate(msdia_dll, CLSID_DiaSource, IID_IDiaDataSource,
+                              reinterpret_cast<void **>(&data_source)))) {
+    return true;
+  }
+
+  return false;
+}
+
 }  // namespace
 
 PDBSourceLineWriter::PDBSourceLineWriter() : output_(NULL) {
@@ -149,13 +184,10 @@ bool PDBSourceLineWriter::Open(const wstring &file, FileFormat format) {
   }
 
   CComPtr<IDiaDataSource> data_source;
-  if (FAILED(data_source.CoCreateInstance(CLSID_DiaSource))) {
+  if (!CreateDiaDataSourceInstance(data_source)) {
     const int kGuidSize = 64;
     wchar_t classid[kGuidSize] = {0};
     StringFromGUID2(CLSID_DiaSource, classid, kGuidSize);
-    // vc80 uses bce36434-2c24-499e-bf49-8bd99b0eeb68.
-    // vc90 uses 4C41678E-887B-4365-A09E-925D28DB33C2.
-    // vc100 uses B86AE24D-BF2F-4AC9-B5A2-34B14E4CE11D.
     fprintf(stderr, "CoCreateInstance CLSID_DiaSource %S failed "
             "(msdia*.dll unregistered?)\n", classid);
     return false;