[MemProf] Context disambiguation cloning pass [patch 1b/3]

Adds support for building the graph in ThinLTO from MemProf summaries.

Follow-on patches will contain the support for cloning on the graph and
in the IR.

Depends on D140908.

Differential Revision: https://reviews.llvm.org/D145836

1 files changed, 12 insertions, 4 deletions

diff --git a/llvm/lib/LTO/LTO.cpp b/llvm/lib/LTO/LTO.cpp
index 1f273a8..ee6b8c3 100644
--- a/llvm/lib/LTO/LTO.cpp
+++ b/llvm/lib/LTO/LTO.cpp
@@ -51,6 +51,7 @@
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/Transforms/IPO.h"
+#include "llvm/Transforms/IPO/MemProfContextDisambiguation.h"
 #include "llvm/Transforms/IPO/WholeProgramDevirt.h"
 #include "llvm/Transforms/Utils/FunctionImportUtils.h"
 #include "llvm/Transforms/Utils/SplitModule.h"
@@ -75,6 +76,9 @@ cl::opt<bool> EnableLTOInternalization(
     cl::desc("Enable global value internalization in LTO"));
 }
 
+/// Enable MemProf context disambiguation for thin link.
+extern cl::opt<bool> EnableMemProfContextDisambiguation;
+
 // Computes a unique hash for the Module considering the current list of
 // export/import and other global analysis results.
 // The hash is produced in \p Key.
@@ -1539,6 +1543,14 @@ Error LTO::runThinLTO(AddStreamFn AddStream, FileCache Cache,
   runWholeProgramDevirtOnIndex(ThinLTO.CombinedIndex, ExportedGUIDs,
                                LocalWPDTargetsMap);
 
+  auto isPrevailing = [&](GlobalValue::GUID GUID, const GlobalValueSummary *S) {
+    return ThinLTO.PrevailingModuleForGUID[GUID] == S->modulePath();
+  };
+  if (EnableMemProfContextDisambiguation) {
+    MemProfContextDisambiguation ContextDisambiguation;
+    ContextDisambiguation.run(ThinLTO.CombinedIndex, isPrevailing);
+  }
+
   if (Conf.OptLevel > 0)
     ComputeCrossModuleImport(ThinLTO.CombinedIndex, ModuleToDefinedGVSummaries,
                              ImportLists, ExportLists);
@@ -1580,10 +1592,6 @@ Error LTO::runThinLTO(AddStreamFn AddStream, FileCache Cache,
   updateIndexWPDForExports(ThinLTO.CombinedIndex, isExported,
                            LocalWPDTargetsMap);
 
-  auto isPrevailing = [&](GlobalValue::GUID GUID,
-                          const GlobalValueSummary *S) {
-    return ThinLTO.PrevailingModuleForGUID[GUID] == S->modulePath();
-  };
   thinLTOInternalizeAndPromoteInIndex(ThinLTO.CombinedIndex, isExported,
                                       isPrevailing);