Get the file name for the symbol from the Module, not the SourceManager.

[v.g.vassilev]

Summary

This allows multi-module / incremental compilation environments to have unique initializer symbols.

Patch by Axel Naumann!

[rsmith]

Is there any way to add a test for this? Does it affect the behavior of clang or any in-tree clang-based tools?

If this isn't visible through existing in-tree tools, it would be useful to add to unittests/ a rough skeleton of what you're doing, so you can add tests for this kind of thing, and so we don't regress functionality you're depending on.

[v.g.vassilev]

Add a test case.

[v.g.vassilev]

Update test file comment.

[rsmith]

Looks good, thanks!

[v.g.vassilev]

Landed in r311844.

lib/CodeGen/CGDeclCXX.cpp

for (SmallVectorImpl<GlobalInitData >::iterator
         LocalCXXGlobalInits.push_back(I->second);
 
       CodeGenFunction(*this).GenerateCXXGlobalInitFunc(Fn, LocalCXXGlobalInits);
       AddGlobalCtor(Fn, Priority);
     }
     PrioritizedCXXGlobalInits.clear();
   }
 
-  SmallString<128> FileName;
-  SourceManager &SM = Context.getSourceManager();
-  if (const FileEntry *MainFile = SM.getFileEntryForID(SM.getMainFileID())) {
-    // Include the filename in the symbol name. Including "sub_" matches gcc and
-    // makes sure these symbols appear lexicographically behind the symbols with
-    // priority emitted above.
-    FileName = llvm::sys::path::filename(MainFile->getName());
-  } else {
+  SmallString<128> FileName = llvm::sys::path::filename(getModule().getName());
+  if (FileName.empty())
     FileName = "<null>";
-  }
 
   for (size_t i = 0; i < FileName.size(); ++i) {
     // Replace everything that's not [a-zA-Z0-9._] with a _. This set happens
     // to be the set of C preprocessing numbers.
     if (!isPreprocessingNumberBody(FileName[i]))
       FileName[i] = '_';
   }