[PATCH] D81911: [ThinLTO] Work around getBaseObject returning null for alias-to-ifunc

[Itay Bookstein via Phabricator via llvm-commits]

nextsilicon-itay-bookstein updated this revision to Diff 290307.
nextsilicon-itay-bookstein added a comment.

I have updated the diff to include the changes you suggested. However, as you said, for the test to have a chance of passing, https://reviews.llvm.org/D82745 is required. I will send out a mail to discuss the design issue on llvm-dev soon.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D81911/new/

https://reviews.llvm.org/D81911

Files:
  llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
  llvm/test/Bitcode/thinlto-summary-alias-ifunc.ll


Index: llvm/test/Bitcode/thinlto-summary-alias-ifunc.ll
===================================================================
--- /dev/null
+++ llvm/test/Bitcode/thinlto-summary-alias-ifunc.ll
@@ -0,0 +1,19 @@
+; RUN: opt -module-summary %s -o - | llvm-bcanalyzer -dump | FileCheck %s
+
+; PR46340
+; Check that alias-to-ifunc is properly generated in the module summary.
+
+; CHECK: <GLOBALVAL_SUMMARY_BLOCK
+; CHECK: <ALIAS
+; CHECK: </GLOBALVAL_SUMMARY_BLOCK>
+
+ at bar = dso_local alias void (), void ()* @foo
+ at foo = dso_local ifunc void (), bitcast (i8* ()* @foo_ifunc to void ()*)
+
+define internal i8* @foo_ifunc() {
+  ret i8* bitcast (void ()* @foo_impl to i8*)
+}
+
+define internal void @foo_impl() {
+  ret void
+}
Index: llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
===================================================================
--- llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
+++ llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
@@ -618,6 +618,16 @@
   Index.addGlobalValueSummary(V, std::move(GVarSummary));
 }
 
+static const GlobalValue *getAliasee(const GlobalAlias &A)
+{
+  const GlobalValue *Aliasee = A.getBaseObject();
+  if (Aliasee)
+    return Aliasee;
+
+  // Workaround for PR46340
+  return dyn_cast<GlobalIFunc>(A.getAliasee());
+}
+
 static void
 computeAliasSummary(ModuleSummaryIndex &Index, const GlobalAlias &A,
                     DenseSet<GlobalValue::GUID> &CantBePromoted) {
@@ -626,7 +636,8 @@
                                     /* Live = */ false, A.isDSOLocal(),
                                     A.hasLinkOnceODRLinkage() && A.hasGlobalUnnamedAddr());
   auto AS = std::make_unique<AliasSummary>(Flags);
-  auto *Aliasee = A.getBaseObject();
+  auto *Aliasee = getAliasee(A);
+  assert(Aliasee && "Aliasee is null");
   auto AliaseeVI = Index.getValueInfo(Aliasee->getGUID());
   assert(AliaseeVI && "Alias expects aliasee summary to be available");
   assert(AliaseeVI.getSummaryList().size() == 1 &&


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