nemanjai created this revision.
nemanjai added a reviewer: rsmith.
Herald added a subscriber: jdoerfert.
Herald added a project: clang.
When the `Preprocessor (PP)` in compiler instance is going away, we should
clear the cache of any pointers that it owns as they will be destroyed.
This is one possible fix for the issue I outlined in
http://lists.llvm.org/pipermail/cfe-dev/2019-February/061293.html that received
no responses. We have now encountered the issue in multiple internal buildbots
and I have even seen it in external bots as well. This really should be fixed.
As outlined in my cfe-dev post, it is exceedingly difficult to produce a
reliable test case for this (at least for me) so I have not provided one.
If others should be on the list of reviewers, please add them.
Repository:
rC Clang
https://reviews.llvm.org/D58497
Files:
lib/Frontend/CompilerInstance.cpp
Index: lib/Frontend/CompilerInstance.cpp
===================================================================
--- lib/Frontend/CompilerInstance.cpp
+++ lib/Frontend/CompilerInstance.cpp
@@ -374,7 +374,14 @@
// The module manager holds a reference to the old preprocessor (if any).
ModuleManager.reset();
- // Create the Preprocessor.
+ // Create the Preprocessor. If this instance is replacing the existing
+ // preprocessor and that existing one is going away, we have to remove
+ // the Module* pointers it owns from KnownModules since they will be
+ // dangling. FIXME: Should this only remove pointers owned by the
+ // preprocessor that is going away or clear the entire map (or can
+ // the map even own any other Module* pointers)?
+ if (PP.unique())
+ KnownModules.clear();
HeaderSearch *HeaderInfo =
new HeaderSearch(getHeaderSearchOptsPtr(), getSourceManager(),
getDiagnostics(), getLangOpts(), &getTarget());
Index: lib/Frontend/CompilerInstance.cpp
===================================================================
--- lib/Frontend/CompilerInstance.cpp
+++ lib/Frontend/CompilerInstance.cpp
@@ -374,7 +374,14 @@
// The module manager holds a reference to the old preprocessor (if any).
ModuleManager.reset();
- // Create the Preprocessor.
+ // Create the Preprocessor. If this instance is replacing the existing
+ // preprocessor and that existing one is going away, we have to remove
+ // the Module* pointers it owns from KnownModules since they will be
+ // dangling. FIXME: Should this only remove pointers owned by the
+ // preprocessor that is going away or clear the entire map (or can
+ // the map even own any other Module* pointers)?
+ if (PP.unique())
+ KnownModules.clear();
HeaderSearch *HeaderInfo =
new HeaderSearch(getHeaderSearchOptsPtr(), getSourceManager(),
getDiagnostics(), getLangOpts(), &getTarget());
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