[ViewCFG] Allow printing edge weights in debuggers

[hoyFB]

Summary

Extending the Function::viewCFG prototypes to allow for printing block probability info in form of .dot files during debugging.

Also avoiding an AV when no BFI/BPI available.

[hoyFB]

Updating D77978: [ViewCFG] Allow printing edge weights in debuggers

[hoyFB]

Updating D77978: [ViewCFG] Allow printing edge weights in debuggers

[wenlei]

Thanks for the change - this comes in handy for debugger. LGTM.

llvm/include/llvm/Analysis/CFGPrinter.h

71

nit: when raw weights is printed, both BFI and BPI is needed. The comment is slightly confusing, though functionality-wise it's fine as EdgeWeights is always checked before RawWeights.

[hoyFB]

Updating D77978: [ViewCFG] Allow printing edge weights in debuggers

[hoyFB]

Decorated BFI/BPI parameters with const.

[davidxl]

CFGPrinter.cpp has a viewCFG method -- that one should be replaced with the new interface as well.

[hoyFB]

Updating D77978: [ViewCFG] Allow printing edge weights in debuggers

[hoyFB]

@davidxl Please let me know if you have more feedbacks. Thanks.

[davidxl]

lgtm

[MaskRay]

Delete Test Plan: if you don't intend to add anything.

[hoyFB]

Updating D77978: [ViewCFG] Allow printing edge weights in debuggers

[hoyFB]

Rebased and capitalized function parameter names.

llvm/include/llvm/Analysis/CFGPrinter.h

private:
   bool ShowHeat;
   bool EdgeWeights;
   bool RawWeights;
 
 public:
   DOTFuncInfo(const Function *F) : DOTFuncInfo(F, nullptr, nullptr, 0) {}
 
   DOTFuncInfo(const Function *F, const BlockFrequencyInfo *BFI,
-              BranchProbabilityInfo *BPI, uint64_t MaxFreq)
+              const BranchProbabilityInfo *BPI, uint64_t MaxFreq)
       : F(F), BFI(BFI), BPI(BPI), MaxFreq(MaxFreq) {
     ShowHeat = false;
-    EdgeWeights = true;
-    RawWeights = true;
+    EdgeWeights = !!BPI; // Print EdgeWeights when BPI is available.
+    RawWeights = !!BFI;  // Print RawWeights when BFI is available.
   }
 
   const BlockFrequencyInfo *getBFI() { return BFI; }
 
   const BranchProbabilityInfo *getBPI() { return BPI; }
 
   const Function *getFunction() { return this->F; }
 

llvm/include/llvm/IR/Function.h

 class Constant;
 class DISubprogram;
 class LLVMContext;
 class Module;
 template <typename T> class Optional;
 class raw_ostream;
 class Type;
 class User;
+class BranchProbabilityInfo;
+class BlockFrequencyInfo;
 
 class Function : public GlobalObject, public ilist_node<Function> {
 public:
   using BasicBlockListType = SymbolTableList<BasicBlock>;
 
   // BasicBlock iterators...
   using iterator = BasicBlockListType::iterator;
   using const_iterator = BasicBlockListType::const_iterator;
/// @}
   /// viewCFG - This function is meant for use from the debugger.  You can just
   /// say 'call F->viewCFG()' and a ghostview window should pop up from the
   /// program, displaying the CFG of the current function with the code for each
   /// basic block inside.  This depends on there being a 'dot' and 'gv' program
   /// in your path.
   ///
   void viewCFG() const;
 
+  /// Extended form to print edge weights.
+  void viewCFG(bool ViewCFGOnly, const BlockFrequencyInfo *BFI,
+               const BranchProbabilityInfo *BPI) const;
+
   /// viewCFGOnly - This function is meant for use from the debugger.  It works
   /// just like viewCFG, but it does not include the contents of basic blocks
   /// into the nodes, just the label.  If you are only interested in the CFG
   /// this can make the graph smaller.
   ///
   void viewCFGOnly() const;
 
+  /// Extended form to print edge weights.
+  void viewCFGOnly(const BlockFrequencyInfo *BFI,
+                   const BranchProbabilityInfo *BPI) const;
+
   /// Methods for support type inquiry through isa, cast, and dyn_cast:
   static bool classof(const Value *V) {
     return V->getValueID() == Value::FunctionVal;
   }
 
   /// dropAllReferences() - This method causes all the subinstructions to "let
   /// go" of all references that they are maintaining.  This allows one to
   /// 'delete' a whole module at a time, even though there may be circular

llvm/lib/Analysis/CFGPrinter.cpp

static void writeCFGToDotFile(Function &F, BlockFrequencyInfo *BFI,
 
   if (!EC)
     WriteGraph(File, &CFGInfo, CFGOnly);
   else
     errs() << "  error opening file for writing!";
   errs() << "\n";
 }
 
-static void viewCFG(Function &F, BlockFrequencyInfo *BFI,
-                    BranchProbabilityInfo *BPI, uint64_t MaxFreq,
+static void viewCFG(Function &F, const BlockFrequencyInfo *BFI,
+                    const BranchProbabilityInfo *BPI, uint64_t MaxFreq,
                     bool CFGOnly = false) {
   DOTFuncInfo CFGInfo(&F, BFI, BPI, MaxFreq);
   CFGInfo.setHeatColors(ShowHeatColors);
   CFGInfo.setEdgeWeights(ShowEdgeWeight);
   CFGInfo.setRawEdgeWeights(UseRawEdgeWeight);
 
   ViewGraph(&CFGInfo, "cfg." + F.getName(), CFGOnly);
 }
PreservedAnalyses CFGOnlyPrinterPass::run(Function &F,
   return PreservedAnalyses::all();
 }
 
 /// viewCFG - This function is meant for use from the debugger.  You can just
 /// say 'call F->viewCFG()' and a ghostview window should pop up from the
 /// program, displaying the CFG of the current function.  This depends on there
 /// being a 'dot' and 'gv' program in your path.
 ///
-void Function::viewCFG() const {
+void Function::viewCFG() const { viewCFG(false, nullptr, nullptr); }
+
+void Function::viewCFG(bool ViewCFGOnly, const BlockFrequencyInfo *BFI,
+                       const BranchProbabilityInfo *BPI) const {
   if (!CFGFuncName.empty() && !getName().contains(CFGFuncName))
     return;
-  DOTFuncInfo CFGInfo(this);
-  ViewGraph(&CFGInfo, "cfg" + getName());
+  DOTFuncInfo CFGInfo(this, BFI, BPI, BFI ? getMaxFreq(*this, BFI) : 0);
+  ViewGraph(&CFGInfo, "cfg" + getName(), ViewCFGOnly);
 }
 
 /// viewCFGOnly - This function is meant for use from the debugger.  It works
 /// just like viewCFG, but it does not include the contents of basic blocks
 /// into the nodes, just the label.  If you are only interested in the CFG
 /// this can make the graph smaller.
 ///
-void Function::viewCFGOnly() const {
-  if (!CFGFuncName.empty() && !getName().contains(CFGFuncName))
-    return;
-  DOTFuncInfo CFGInfo(this);
-  ViewGraph(&CFGInfo, "cfg" + getName(), true);
+void Function::viewCFGOnly() const { viewCFGOnly(nullptr, nullptr); }
+
+void Function::viewCFGOnly(const BlockFrequencyInfo *BFI,
+                           const BranchProbabilityInfo *BPI) const {
+  viewCFG(true, BFI, BPI);
 }
 
 FunctionPass *llvm::createCFGPrinterLegacyPassPass() {
   return new CFGPrinterLegacyPass();
 }
 
 FunctionPass *llvm::createCFGOnlyPrinterLegacyPassPass() {
   return new CFGOnlyPrinterLegacyPass();