Merging r323034:

------------------------------------------------------------------------
r323034 | dmgreen | 2018-01-20 11:29:37 +0100 (Sat, 20 Jan 2018) | 9 lines

[Dominators] Fix some edge cases for PostDomTree updating

These fix some odd cfg cases where batch-updating the post
dom tree fails. Usually around infinite loops and roots
ending up being different.

Differential Revision: https://reviews.llvm.org/D42247


------------------------------------------------------------------------


git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_60@323121 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 21 insertions, 55 deletions

diff --git a/include/llvm/MC/MCCodeView.h b/include/llvm/MC/MCCodeView.h
index e2249f49c86..c8f14515ed3 100644
--- a/include/llvm/MC/MCCodeView.h
+++ b/include/llvm/MC/MCCodeView.h
@@ -177,13 +177,7 @@ public:
                                unsigned IACol);
 
   /// Retreive the function info if this is a valid function id, or nullptr.
-  MCCVFunctionInfo *getCVFunctionInfo(unsigned FuncId) {
-    if (FuncId >= Functions.size())
-      return nullptr;
-    if (Functions[FuncId].isUnallocatedFunctionInfo())
-      return nullptr;
-    return &Functions[FuncId];
-  }
+  MCCVFunctionInfo *getCVFunctionInfo(unsigned FuncId);
 
   /// Saves the information from the currently parsed .cv_loc directive
   /// and sets CVLocSeen.  When the next instruction is assembled an entry
@@ -199,50 +193,22 @@ public:
     CurrentCVLoc.setIsStmt(IsStmt);
     CVLocSeen = true;
   }
-  void clearCVLocSeen() { CVLocSeen = false; }
 
   bool getCVLocSeen() { return CVLocSeen; }
+  void clearCVLocSeen() { CVLocSeen = false; }
+
   const MCCVLoc &getCurrentCVLoc() { return CurrentCVLoc; }
 
   bool isValidCVFileNumber(unsigned FileNumber);
 
   /// \brief Add a line entry.
-  void addLineEntry(const MCCVLineEntry &LineEntry) {
-    size_t Offset = MCCVLines.size();
-    auto I = MCCVLineStartStop.insert(
-        {LineEntry.getFunctionId(), {Offset, Offset + 1}});
-    if (!I.second)
-      I.first->second.second = Offset + 1;
-    MCCVLines.push_back(LineEntry);
-  }
+  void addLineEntry(const MCCVLineEntry &LineEntry);
 
-  std::vector<MCCVLineEntry> getFunctionLineEntries(unsigned FuncId) {
-    std::vector<MCCVLineEntry> FilteredLines;
+  std::vector<MCCVLineEntry> getFunctionLineEntries(unsigned FuncId);
 
-    auto I = MCCVLineStartStop.find(FuncId);
-    if (I != MCCVLineStartStop.end())
-      for (size_t Idx = I->second.first, End = I->second.second; Idx != End;
-           ++Idx)
-        if (MCCVLines[Idx].getFunctionId() == FuncId)
-          FilteredLines.push_back(MCCVLines[Idx]);
-    return FilteredLines;
-  }
-
-  std::pair<size_t, size_t> getLineExtent(unsigned FuncId) {
-    auto I = MCCVLineStartStop.find(FuncId);
-    // Return an empty extent if there are no cv_locs for this function id.
-    if (I == MCCVLineStartStop.end())
-      return {~0ULL, 0};
-    return I->second;
-  }
+  std::pair<size_t, size_t> getLineExtent(unsigned FuncId);
 
-  ArrayRef<MCCVLineEntry> getLinesForExtent(size_t L, size_t R) {
-    if (R <= L)
-      return None;
-    if (L >= MCCVLines.size())
-      return None;
-    return makeArrayRef(&MCCVLines[L], R - L);
-  }
+  ArrayRef<MCCVLineEntry> getLinesForExtent(size_t L, size_t R);
 
   /// Emits a line table substream.
   void emitLineTableForFunction(MCObjectStreamer &OS, unsigned FuncId,
diff --git a/include/llvm/Support/GenericDomTreeConstruction.h b/include/llvm/Support/GenericDomTreeConstruction.h
index e85ac76c780..25175fe66aa 100644
--- a/include/llvm/Support/GenericDomTreeConstruction.h
+++ b/include/llvm/Support/GenericDomTreeConstruction.h
@@ -706,7 +706,7 @@ struct SemiNCAInfo {
       // algorithm does not really know or use the set of roots and can make a
       // different (implicit) decision about which nodes within an infinite loop
       // becomes a root.
-      if (DT.isVirtualRoot(TN->getIDom())) {
+      if (TN && !DT.isVirtualRoot(TN->getIDom())) {
         DEBUG(dbgs() << "Root " << BlockNamePrinter(R)
                      << " is not virtual root's child\n"
                      << "The entire tree needs to be rebuilt\n");
@@ -940,21 +940,21 @@ struct SemiNCAInfo {
     const NodePtr NCDBlock = DT.findNearestCommonDominator(From, To);
     const TreeNodePtr NCD = DT.getNode(NCDBlock);
 
-    // To dominates From -- nothing to do.
-    if (ToTN == NCD) return;
+    // If To dominates From -- nothing to do.
+    if (ToTN != NCD) {
+      DT.DFSInfoValid = false;
 
-    DT.DFSInfoValid = false;
-
-    const TreeNodePtr ToIDom = ToTN->getIDom();
-    DEBUG(dbgs() << "\tNCD " << BlockNamePrinter(NCD) << ", ToIDom "
-                 << BlockNamePrinter(ToIDom) << "\n");
+      const TreeNodePtr ToIDom = ToTN->getIDom();
+      DEBUG(dbgs() << "\tNCD " << BlockNamePrinter(NCD) << ", ToIDom "
+                   << BlockNamePrinter(ToIDom) << "\n");
 
-    // To remains reachable after deletion.
-    // (Based on the caption under Figure 4. from the second paper.)
-    if (FromTN != ToIDom || HasProperSupport(DT, BUI, ToTN))
-      DeleteReachable(DT, BUI, FromTN, ToTN);
-    else
-      DeleteUnreachable(DT, BUI, ToTN);
+      // To remains reachable after deletion.
+      // (Based on the caption under Figure 4. from the second paper.)
+      if (FromTN != ToIDom || HasProperSupport(DT, BUI, ToTN))
+        DeleteReachable(DT, BUI, FromTN, ToTN);
+      else
+        DeleteUnreachable(DT, BUI, ToTN);
+    }
 
     if (IsPostDom) UpdateRootsAfterUpdate(DT, BUI);
   }