[modules] Fix incorrect diagnostic mapping computation when a module changes
diagnostic settings using _Pragma within a macro.
The AST writer had previously been assuming that all diagnostic state
transitions would occur within a FileID corresponding to a file. When a
diagnostic state change occured within a macro, it was unable to form a
location for that state change and would instead corrupt the diagnostic state
of the "root" node (and thus that of the main compilation).
Also introduce a "#pragma clang __debug diag_mapping" debugging utility
that I added to track this issue down.
llvm-svn: 324695
diff --git a/clang/lib/Serialization/ASTWriter.cpp b/clang/lib/Serialization/ASTWriter.cpp
index 50c60fe..8c5863e 100644
--- a/clang/lib/Serialization/ASTWriter.cpp
+++ b/clang/lib/Serialization/ASTWriter.cpp
@@ -3092,8 +3092,11 @@
!FileIDAndFile.second.HasLocalTransitions)
continue;
++NumLocations;
- AddSourceLocation(Diag.SourceMgr->getLocForStartOfFile(FileIDAndFile.first),
- Record);
+
+ SourceLocation Loc = Diag.SourceMgr->getComposedLoc(FileIDAndFile.first, 0);
+ assert(!Loc.isInvalid() && "start loc for valid FileID is invalid");
+ AddSourceLocation(Loc, Record);
+
Record.push_back(FileIDAndFile.second.StateTransitions.size());
for (auto &StatePoint : FileIDAndFile.second.StateTransitions) {
Record.push_back(StatePoint.Offset);