[PATCH] D104497: [CSSPGO][llvm-profgen] Fix an issue in findDisjointRanges

[Hongtao Yu via Phabricator via llvm-commits]

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We were using 0 as an indicator of invalid offset when computing disjoint ranges. In reality, 0 can be an valid code offset which stands for the first function in .text section. I'm using UINT64_MAX as an invalid code offset instead.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D104497

Files:
  llvm/tools/llvm-profgen/ProfileGenerator.cpp


Index: llvm/tools/llvm-profgen/ProfileGenerator.cpp
===================================================================
--- llvm/tools/llvm-profgen/ProfileGenerator.cpp
+++ llvm/tools/llvm-profgen/ProfileGenerator.cpp
@@ -174,19 +174,20 @@
     Boundaries[End].addEndCount(Count);
   }
 
-  uint64_t BeginAddress = 0;
+  uint64_t BeginAddress = UINT64_MAX;
   int Count = 0;
   for (auto Item : Boundaries) {
     uint64_t Address = Item.first;
     BoundaryPoint &Point = Item.second;
     if (Point.BeginCount) {
-      if (BeginAddress)
+      if (BeginAddress != UINT64_MAX)
         DisjointRanges[{BeginAddress, Address - 1}] = Count;
       Count += Point.BeginCount;
       BeginAddress = Address;
     }
     if (Point.EndCount) {
-      assert(BeginAddress && "First boundary point cannot be 'end' point");
+      assert((BeginAddress != UINT64_MAX) &&
+             "First boundary point cannot be 'end' point");
       DisjointRanges[{BeginAddress, Address}] = Count;
       Count -= Point.EndCount;
       BeginAddress = Address + 1;


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