Store GUIDs in metadatausers/orodley/guid-2

See https://discourse.llvm.org/t/rfc-keep-globalvalue-guids-stable/84801
for context.

This takes the existing AssignGUID pass from CtxProfAnalysis, and runs
it by default, at the appropriate stages of the LTO pipeline. It also
changes GlobalValue::getGUID() to retrieve the GUID from the metadata
instead of computing it.

We don't yet have the supporting downstream changes to make a dedicated
GUID table in bitcode, nor do we use the metadata as part of ThinLTO --
it retains its existing mechanisms of recomputing GUIDs from separately
saved data. That will be changed later.

1 files changed, 8 insertions, 0 deletions

diff --git a/llvm/tools/opt/NewPMDriver.cpp b/llvm/tools/opt/NewPMDriver.cpp
index b9b8929..5586969 100644
--- a/llvm/tools/opt/NewPMDriver.cpp
+++ b/llvm/tools/opt/NewPMDriver.cpp
@@ -39,6 +39,7 @@
 #include "llvm/Transforms/IPO/ThinLTOBitcodeWriter.h"
 #include "llvm/Transforms/Instrumentation/AddressSanitizer.h"
 #include "llvm/Transforms/Scalar/LoopPassManager.h"
+#include "llvm/Transforms/Utils/AssignGUID.h"
 #include "llvm/Transforms/Utils/Debugify.h"
 #include "llvm/Transforms/Utils/ProfileVerify.h"
 
@@ -514,14 +515,21 @@ bool llvm::runPassPipeline(
   case OK_NoOutput:
     break; // No output pass needed.
   case OK_OutputAssembly:
+    if (EmitSummaryIndex) {
+      MPM.addPass(AssignGUIDPass());
+    }
     MPM.addPass(PrintModulePass(
         Out->os(), "", ShouldPreserveAssemblyUseListOrder, EmitSummaryIndex));
     break;
   case OK_OutputBitcode:
+    if (EmitSummaryIndex) {
+      MPM.addPass(AssignGUIDPass());
+    }
     MPM.addPass(BitcodeWriterPass(Out->os(), ShouldPreserveBitcodeUseListOrder,
                                   EmitSummaryIndex, EmitModuleHash));
     break;
   case OK_OutputThinLTOBitcode:
+    MPM.addPass(AssignGUIDPass());
     MPM.addPass(ThinLTOBitcodeWriterPass(
         Out->os(), ThinLTOLinkOut ? &ThinLTOLinkOut->os() : nullptr,
         ShouldPreserveBitcodeUseListOrder));