[BOLT][NFC] Split out DomTree construction from BF::calculateLoopInfo (#87181)

Author: aaupov

bolt/include/bolt/Core/BinaryFunction.h

@@ -27,6 +27,7 @@
 
 #include "bolt/Core/BinaryBasicBlock.h"
 #include "bolt/Core/BinaryContext.h"
+#include "bolt/Core/BinaryDomTree.h"
 #include "bolt/Core/BinaryLoop.h"
 #include "bolt/Core/BinarySection.h"
 #include "bolt/Core/DebugData.h"
@@ -266,6 +267,7 @@ class BinaryFunction {
   BinaryContext &BC;
 
   std::unique_ptr<BinaryLoopInfo> BLI;
+  std::unique_ptr<BinaryDominatorTree> BDT;
 
   /// All labels in the function that are referenced via relocations from
   /// data objects. Typically these are jump table destinations and computed
@@ -838,6 +840,14 @@ class BinaryFunction {
   /// stats.
   void calculateMacroOpFusionStats();
 
+  /// Returns if BinaryDominatorTree has been constructed for this function.
+  bool hasDomTree() const { return BDT != nullptr; }
+
+  BinaryDominatorTree &getDomTree() { return *BDT.get(); }
+
+  /// Constructs DomTree for this function.
+  void constructDomTree();
+
   /// Returns if loop detection has been run for this function.
   bool hasLoopInfo() const { return BLI != nullptr; }
 

bolt/lib/Core/BinaryFunction.cpp

@@ -12,7 +12,6 @@
 
 #include "bolt/Core/BinaryFunction.h"
 #include "bolt/Core/BinaryBasicBlock.h"
-#include "bolt/Core/BinaryDomTree.h"
 #include "bolt/Core/DynoStats.h"
 #include "bolt/Core/HashUtilities.h"
 #include "bolt/Core/MCPlusBuilder.h"
@@ -4076,12 +4075,17 @@ BinaryFunction::~BinaryFunction() {
     delete BB;
 }
 
+void BinaryFunction::constructDomTree() {
+  BDT.reset(new BinaryDominatorTree);
+  BDT->recalculate(*this);
+}
+
 void BinaryFunction::calculateLoopInfo() {
+  if (!hasDomTree())
+    constructDomTree();
   // Discover loops.
-  BinaryDominatorTree DomTree;
-  DomTree.recalculate(*this);
   BLI.reset(new BinaryLoopInfo());
-  BLI->analyze(DomTree);
+  BLI->analyze(getDomTree());
 
   // Traverse discovered loops and add depth and profile information.
   std::stack<BinaryLoop *> St;