[llvm] r335444 - [MSSA] Add domination number verifier; NFC

[George Burgess IV via llvm-commits]

Author: gbiv
Date: Sun Jun 24 22:30:36 2018
New Revision: 335444

URL: http://llvm.org/viewvc/llvm-project?rev=335444&view=rev
Log:
[MSSA] Add domination number verifier; NFC

It's easy for domination numbers to get out-of-date, and this is no more
costly than any of the other verifiers we already have, so it seems nice
to have.

A stage3 build with this Works On My Machine, so this hasn't caught any
bugs... yet. :)

Modified:
    llvm/trunk/include/llvm/Analysis/MemorySSA.h
    llvm/trunk/lib/Analysis/MemorySSA.cpp

Modified: llvm/trunk/include/llvm/Analysis/MemorySSA.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/MemorySSA.h?rev=335444&r1=335443&r2=335444&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/MemorySSA.h (original)
+++ llvm/trunk/include/llvm/Analysis/MemorySSA.h Sun Jun 24 22:30:36 2018
@@ -722,6 +722,7 @@ protected:
   void verifyDefUses(Function &F) const;
   void verifyDomination(Function &F) const;
   void verifyOrdering(Function &F) const;
+  void verifyDominationNumbers(const Function &F) const;
 
   // This is used by the use optimizer and updater.
   AccessList *getWritableBlockAccesses(const BasicBlock *BB) const {

Modified: llvm/trunk/lib/Analysis/MemorySSA.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/MemorySSA.cpp?rev=335444&r1=335443&r2=335444&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/MemorySSA.cpp (original)
+++ llvm/trunk/lib/Analysis/MemorySSA.cpp Sun Jun 24 22:30:36 2018
@@ -1633,9 +1633,48 @@ void MemorySSA::verifyMemorySSA() const
   verifyDefUses(F);
   verifyDomination(F);
   verifyOrdering(F);
+  verifyDominationNumbers(F);
   Walker->verify(this);
 }
 
+/// Verify that all of the blocks we believe to have valid domination numbers
+/// actually have valid domination numbers.
+void MemorySSA::verifyDominationNumbers(const Function &F) const {
+#ifndef NDEBUG
+  if (BlockNumberingValid.empty())
+    return;
+
+  SmallPtrSet<const BasicBlock *, 16> ValidBlocks = BlockNumberingValid;
+  for (const BasicBlock &BB : F) {
+    if (!ValidBlocks.count(&BB))
+      continue;
+
+    ValidBlocks.erase(&BB);
+
+    const AccessList *Accesses = getBlockAccesses(&BB);
+    // It's correct to say an empty block has valid numbering.
+    if (!Accesses)
+      continue;
+
+    // Block numbering starts at 1.
+    unsigned long LastNumber = 0;
+    for (const MemoryAccess &MA : *Accesses) {
+      auto ThisNumberIter = BlockNumbering.find(&MA);
+      assert(ThisNumberIter != BlockNumbering.end() &&
+             "MemoryAccess has no domination number in a valid block!");
+
+      unsigned long ThisNumber = ThisNumberIter->second;
+      assert(ThisNumber > LastNumber &&
+             "Domination numbers should be strictly increasing!");
+      LastNumber = ThisNumber;
+    }
+  }
+
+  assert(ValidBlocks.empty() &&
+         "All valid BasicBlocks should exist in F -- dangling pointers?");
+#endif
+}
+
 /// Verify that the order and existence of MemoryAccesses matches the
 /// order and existence of memory affecting instructions.
 void MemorySSA::verifyOrdering(Function &F) const {