[llvm-branch-commits] [llvm-branch] r322545 - Merging r322103:

[Hans Wennborg via llvm-branch-commits]

Author: hans
Date: Tue Jan 16 04:06:38 2018
New Revision: 322545

URL: http://llvm.org/viewvc/llvm-project?rev=322545&view=rev
Log:
Merging r322103:
------------------------------------------------------------------------
r322103 | tejohnson | 2018-01-09 10:32:53 -0800 (Tue, 09 Jan 2018) | 25 lines

Fix crash when linking metadata with ODR type uniquing

Summary:
With DebugTypeODRUniquing enabled, during IR linking debug metadata
in the destination module may be reached from the source module.
This means that ConstantAsMetadata nodes (e.g. on DITemplateValueParameter)
may contain a value the destination module. When trying to map such
metadata nodes, we will attempt to map a GV already in the dest module.
linkGlobalValueProto will end up with a source GV that is the same as
the dest GV as well as the new GV. Trying to access the TypeMap for the
source GV type, which is actually a dest GV type, hits an assertion
since it appears that we have mapped into the source module (because the
type is the value not a key into the map).

Detect that we don't need to access the TypeMap in this case, since
there is no need to create a bitcast from the new GV to the source GV
type as they GV are the same.

Fixes PR35722.

Reviewers: mehdi_amini, pcc

Subscribers: probinson, llvm-commits, eraman

Differential Revision: https://reviews.llvm.org/D41624
------------------------------------------------------------------------

Added:
    llvm/branches/release_60/test/ThinLTO/X86/Inputs/dicompositetype-unique2.ll
      - copied unchanged from r322103, llvm/trunk/test/ThinLTO/X86/Inputs/dicompositetype-unique2.ll
    llvm/branches/release_60/test/ThinLTO/X86/dicompositetype-unique2.ll
      - copied unchanged from r322103, llvm/trunk/test/ThinLTO/X86/dicompositetype-unique2.ll
Modified:
    llvm/branches/release_60/   (props changed)
    llvm/branches/release_60/lib/Linker/IRMover.cpp

Propchange: llvm/branches/release_60/
------------------------------------------------------------------------------
--- svn:mergeinfo (original)
+++ svn:mergeinfo Tue Jan 16 04:06:38 2018
@@ -1,3 +1,3 @@
 /llvm/branches/Apple/Pertwee:110850,110961
 /llvm/branches/type-system-rewrite:133420-134817
-/llvm/trunk:155241
+/llvm/trunk:155241,322103

Modified: llvm/branches/release_60/lib/Linker/IRMover.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/branches/release_60/lib/Linker/IRMover.cpp?rev=322545&r1=322544&r2=322545&view=diff
==============================================================================
--- llvm/branches/release_60/lib/Linker/IRMover.cpp (original)
+++ llvm/branches/release_60/lib/Linker/IRMover.cpp Tue Jan 16 04:06:38 2018
@@ -954,7 +954,12 @@ Expected<Constant *> IRLinker::linkGloba
     NewGV->setLinkage(GlobalValue::InternalLinkage);
 
   Constant *C = NewGV;
-  if (DGV)
+  // Only create a bitcast if necessary. In particular, with
+  // DebugTypeODRUniquing we may reach metadata in the destination module
+  // containing a GV from the source module, in which case SGV will be
+  // the same as DGV and NewGV, and TypeMap.get() will assert since it
+  // assumes it is being invoked on a type in the source module.
+  if (DGV && NewGV != SGV)
     C = ConstantExpr::getBitCast(NewGV, TypeMap.get(SGV->getType()));
 
   if (DGV && NewGV != DGV) {