[PATCH] D26049: [ThinLTO] Create AliasSummary when building index

[Teresa Johnson via llvm-commits]

tejohnson created this revision.
tejohnson added a reviewer: mehdi_amini.
tejohnson added a subscriber: llvm-commits.

Previously we were creating the alias summary on the fly while writing
the summary to bitcode. This moves the creation of these summaries to
the module summary index builder where we build the rest of the summary
index.


https://reviews.llvm.org/D26049

Files:
  lib/Analysis/ModuleSummaryAnalysis.cpp
  lib/Bitcode/Writer/BitcodeWriter.cpp


Index: lib/Bitcode/Writer/BitcodeWriter.cpp
===================================================================
--- lib/Bitcode/Writer/BitcodeWriter.cpp
+++ lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -3434,7 +3434,9 @@
     auto AliasId = VE.getValueID(&A);
     auto AliaseeId = VE.getValueID(Aliasee);
     NameVals.push_back(AliasId);
-    NameVals.push_back(getEncodedGVSummaryFlags(A));
+    auto *Summary = Index->getGlobalValueSummary(A);
+    AliasSummary *AS = cast<AliasSummary>(Summary);
+    NameVals.push_back(getEncodedGVSummaryFlags(AS->flags()));
     NameVals.push_back(AliaseeId);
     Stream.EmitRecord(bitc::FS_ALIAS, NameVals, FSAliasAbbrev);
     NameVals.clear();
Index: lib/Analysis/ModuleSummaryAnalysis.cpp
===================================================================
--- lib/Analysis/ModuleSummaryAnalysis.cpp
+++ lib/Analysis/ModuleSummaryAnalysis.cpp
@@ -78,10 +78,9 @@
 static void computeFunctionSummary(ModuleSummaryIndex &Index, const Module &M,
                                    const Function &F, BlockFrequencyInfo *BFI,
                                    ProfileSummaryInfo *PSI) {
-  // Summary not currently supported for anonymous functions, they must
-  // be renamed.
-  if (!F.hasName())
-    return;
+  // Summary not currently supported for anonymous functions, they should
+  // have been named.
+  assert(F.hasName());
 
   unsigned NumInsts = 0;
   // Map from callee ValueId to profile count. Used to accumulate profile
@@ -111,9 +110,11 @@
       }
       // Check if this is a direct call to a known function.
       if (CalledFunction) {
-        // Skip nameless and intrinsics.
-        if (!CalledFunction->hasName() || CalledFunction->isIntrinsic())
+        // Skip intrinsics.
+        if (CalledFunction->isIntrinsic())
           continue;
+        // We should have named any anonymous globals
+        assert(CalledFunction->hasName());
         auto ScaledCount = BFI ? BFI->getBlockProfileCount(&BB) : None;
         // Use the original CalledValue, in case it was an alias. We want
         // to record the call edge to the alias in that case. Eventually
@@ -166,6 +167,17 @@
   Index.addGlobalValueSummary(V.getName(), std::move(GVarSummary));
 }
 
+static void computeAliasSummary(ModuleSummaryIndex &Index,
+                                const GlobalAlias &A) {
+  GlobalValueSummary::GVFlags Flags(A);
+  std::unique_ptr<AliasSummary> AS = llvm::make_unique<AliasSummary>(Flags);
+  auto *Aliasee = A.getBaseObject();
+  auto *AliaseeSummary = Index.getGlobalValueSummary(*Aliasee);
+  assert(AliaseeSummary && "Alias expects aliasee summary to be parsed");
+  AS->setAliasee(AliaseeSummary);
+  Index.addGlobalValueSummary(A.getName(), std::move(AS));
+}
+
 ModuleSummaryIndex llvm::buildModuleSummaryIndex(
     const Module &M,
     std::function<BlockFrequencyInfo *(const Function &F)> GetBFICallback,
@@ -204,6 +216,12 @@
       continue;
     computeVariableSummary(Index, G);
   }
+
+  // Compute summaries for all aliases defined in module, and save in the
+  // index.
+  for (const GlobalAlias &A : M.aliases())
+    computeAliasSummary(Index, A);
+
   return Index;
 }
 


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