[PATCH] D79382: [CallGraphUpdater] Removed references to calles when deleting function

[Sergey Dmitriev via Phabricator via llvm-commits]

sdmitriev created this revision.
sdmitriev added a reviewer: jdoerfert.
Herald added subscribers: llvm-commits, hiraditya.
Herald added a reviewer: sstefan1.
Herald added a project: LLVM.

Otherwise we can get unaccounted references to call graph nodes.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D79382

Files:
  llvm/lib/Transforms/Utils/CallGraphUpdater.cpp
  llvm/test/Transforms/Util/cg-updater-dead-function-callees.ll
  llvm/unittests/IR/LegacyPassManagerTest.cpp


Index: llvm/unittests/IR/LegacyPassManagerTest.cpp
===================================================================
--- llvm/unittests/IR/LegacyPassManagerTest.cpp
+++ llvm/unittests/IR/LegacyPassManagerTest.cpp
@@ -687,9 +687,9 @@
       Passes.add(P);
       Passes.run(*M);
       ASSERT_EQ(P->SetupWorked, 1U);
-      ASSERT_EQ(P->NumSCCs, 5U);
-      ASSERT_EQ(P->NumFns, 8U);
-      ASSERT_EQ(P->NumFnDecls, 3U);
+      ASSERT_EQ(P->NumSCCs, 4U);
+      ASSERT_EQ(P->NumFns, 6U);
+      ASSERT_EQ(P->NumFnDecls, 1U);
       ASSERT_EQ(M->getFunctionList().size(), 3U);
       ASSERT_EQ(P->NumExtCalledBefore, /* test1, 2a, 2b, 3, 4 */ 5U);
       ASSERT_EQ(P->NumExtCalledAfter, /* test1, 3repl, 4 */ 3U);
Index: llvm/test/Transforms/Util/cg-updater-dead-function-callees.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/Util/cg-updater-dead-function-callees.ll
@@ -0,0 +1,31 @@
+; RUN: opt -inline -attributor-cgscc -tailcallelim -S %s | FileCheck %s
+;
+; CHECK: define void @foo()
+; CHECK: declare i32 @baz()
+; CHECK-NOT: void @goo()
+; CHECK-NOT: void @bar()
+
+define void @foo() {
+  call fastcc void @bar()
+  ret void
+}
+
+define internal fastcc void @goo() {
+  call fastcc void @bar()
+  ret void
+}
+
+define internal fastcc void @bar() {
+  %call = call i32 @baz()
+  %cond = icmp eq i32 %call, 0
+  br i1 %cond, label %if.then, label %if.end
+
+if.then:
+  call fastcc void @goo()
+  br label %if.end
+
+if.end:
+  ret void
+}
+
+declare i32 @baz()
Index: llvm/lib/Transforms/Utils/CallGraphUpdater.cpp
===================================================================
--- llvm/lib/Transforms/Utils/CallGraphUpdater.cpp
+++ llvm/lib/Transforms/Utils/CallGraphUpdater.cpp
@@ -112,8 +112,11 @@
     DeadFunctions.push_back(&DeadFn);
 
   // For the old call graph we remove the function from the SCC right away.
-  if (CG && !ReplacedFunctions.count(&DeadFn))
-    CGSCC->DeleteNode((*CG)[&DeadFn]);
+  if (CG && !ReplacedFunctions.count(&DeadFn)) {
+    CallGraphNode *DeadCGN = (*CG)[&DeadFn];
+    DeadCGN->removeAllCalledFunctions();
+    CGSCC->DeleteNode(DeadCGN);
+  }
 }
 
 void CallGraphUpdater::replaceFunctionWith(Function &OldFn, Function &NewFn) {


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