vendor/llvm-project/llvmorg-11-init-20887-g2e10b7a39b9vendor/llvm-project/master

1 files changed, 55 insertions, 19 deletions

diff --git a/llvm/lib/Analysis/CallGraphSCCPass.cpp b/llvm/lib/Analysis/CallGraphSCCPass.cpp
index 196ef400bc4e6..91f8029cc326b 100644
--- a/llvm/lib/Analysis/CallGraphSCCPass.cpp
+++ b/llvm/lib/Analysis/CallGraphSCCPass.cpp
@@ -19,6 +19,7 @@
 #include "llvm/ADT/SCCIterator.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/CallGraph.h"
+#include "llvm/IR/AbstractCallSite.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/IRPrintingPasses.h"
 #include "llvm/IR/Intrinsics.h"
@@ -225,22 +226,51 @@ bool CGPassManager::RefreshCallGraph(const CallGraphSCC &CurSCC, CallGraph &CG,
     // invalidated and removed.
     unsigned NumDirectRemoved = 0, NumIndirectRemoved = 0;
 
+    CallGraphNode::iterator CGNEnd = CGN->end();
+
+    auto RemoveAndCheckForDone = [&](CallGraphNode::iterator I) {
+      // Just remove the edge from the set of callees, keep track of whether
+      // I points to the last element of the vector.
+      bool WasLast = I + 1 == CGNEnd;
+      CGN->removeCallEdge(I);
+
+      // If I pointed to the last element of the vector, we have to bail out:
+      // iterator checking rejects comparisons of the resultant pointer with
+      // end.
+      if (WasLast)
+        return true;
+
+      CGNEnd = CGN->end();
+      return false;
+    };
+
     // Get the set of call sites currently in the function.
-    for (CallGraphNode::iterator I = CGN->begin(), E = CGN->end(); I != E; ) {
+    for (CallGraphNode::iterator I = CGN->begin(); I != CGNEnd;) {
+      // Delete "reference" call records that do not have call instruction. We
+      // reinsert them as needed later. However, keep them in checking mode.
+      if (!I->first) {
+        if (CheckingMode) {
+          ++I;
+          continue;
+        }
+        if (RemoveAndCheckForDone(I))
+          break;
+        continue;
+      }
+
       // If this call site is null, then the function pass deleted the call
       // entirely and the WeakTrackingVH nulled it out.
-      auto *Call = dyn_cast_or_null<CallBase>(I->first);
-      if (!I->first ||
+      auto *Call = dyn_cast_or_null<CallBase>(*I->first);
+      if (!Call ||
           // If we've already seen this call site, then the FunctionPass RAUW'd
           // one call with another, which resulted in two "uses" in the edge
           // list of the same call.
-          Calls.count(I->first) ||
+          Calls.count(Call) ||
 
           // If the call edge is not from a call or invoke, or it is a
           // instrinsic call, then the function pass RAUW'd a call with
           // another value. This can happen when constant folding happens
           // of well known functions etc.
-          !Call ||
           (Call->getCalledFunction() &&
            Call->getCalledFunction()->isIntrinsic() &&
            Intrinsic::isLeaf(Call->getCalledFunction()->getIntrinsicID()))) {
@@ -253,28 +283,18 @@ bool CGPassManager::RefreshCallGraph(const CallGraphSCC &CurSCC, CallGraph &CG,
         else
           ++NumDirectRemoved;
 
-        // Just remove the edge from the set of callees, keep track of whether
-        // I points to the last element of the vector.
-        bool WasLast = I + 1 == E;
-        CGN->removeCallEdge(I);
-
-        // If I pointed to the last element of the vector, we have to bail out:
-        // iterator checking rejects comparisons of the resultant pointer with
-        // end.
-        if (WasLast)
+        if (RemoveAndCheckForDone(I))
           break;
-        E = CGN->end();
         continue;
       }
 
-      assert(!Calls.count(I->first) &&
-             "Call site occurs in node multiple times");
+      assert(!Calls.count(Call) && "Call site occurs in node multiple times");
 
       if (Call) {
         Function *Callee = Call->getCalledFunction();
         // Ignore intrinsics because they're not really function calls.
         if (!Callee || !(Callee->isIntrinsic()))
-          Calls.insert(std::make_pair(I->first, I->second));
+          Calls.insert(std::make_pair(Call, I->second));
       }
       ++I;
     }
@@ -292,6 +312,15 @@ bool CGPassManager::RefreshCallGraph(const CallGraphSCC &CurSCC, CallGraph &CG,
         if (Callee && Callee->isIntrinsic())
           continue;
 
+        // If we are not in checking mode, insert potential callback calls as
+        // references. This is not a requirement but helps to iterate over the
+        // functions in the right order.
+        if (!CheckingMode) {
+          forEachCallbackFunction(*Call, [&](Function *CB) {
+            CGN->addCalledFunction(nullptr, CG.getOrInsertFunction(CB));
+          });
+        }
+
         // If this call site already existed in the callgraph, just verify it
         // matches up to expectations and remove it from Calls.
         DenseMap<Value *, CallGraphNode *>::iterator ExistingIt =
@@ -549,7 +578,10 @@ void CallGraphSCC::ReplaceNode(CallGraphNode *Old, CallGraphNode *New) {
   for (unsigned i = 0; ; ++i) {
     assert(i != Nodes.size() && "Node not in SCC");
     if (Nodes[i] != Old) continue;
-    Nodes[i] = New;
+    if (New)
+      Nodes[i] = New;
+    else
+      Nodes.erase(Nodes.begin() + i);
     break;
   }
 
@@ -559,6 +591,10 @@ void CallGraphSCC::ReplaceNode(CallGraphNode *Old, CallGraphNode *New) {
   CGI->ReplaceNode(Old, New);
 }
 
+void CallGraphSCC::DeleteNode(CallGraphNode *Old) {
+  ReplaceNode(Old, /*New=*/nullptr);
+}
+
 //===----------------------------------------------------------------------===//
 // CallGraphSCCPass Implementation
 //===----------------------------------------------------------------------===//