SelectionDAG: add a -filter-view-dags=<string> cmd line option

[mehdi_amini]

Summary

When debugging SelectionDAG on an IR with many basic blocks, It is painful to have to generate the graphviz for the 99 first blocks when you are interested in the 100.
This patch add a string parameter that allows to filter the "block of interest".

[resistor]

What about the idea of filtering by name rather than by number? The problem with filtering by number is that it depends on you already knowing what number block you want to visualize.

[mehdi_amini]

Update to use a sting and match it the BB name.

[mehdi_amini]

+llvm-commit

I don't have a strong opinion between string and number. Number is less messy and you always get them at the MI level or in SelectionDAG, on the other hand string matches the IR so is probably more convenient if you start from there.
I updated with the string version.

[MatzeB]

My 2cents: In another compiler I worked with this simply worked by creating several files on the harddrive. This required you to start the viewer manually but was way more convenient when switching back and forth between different functions and phases of the compilation...

[mehdi_amini]

Yeah I was also thinking about such an option, but it seems orthogonal to the option I implemented here IMO.

Mehdi

[resistor]

Looks fine to me otherwise.

lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp

188

Shouldn't it be "view-*-dags"?

lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp

         cl::init(true), cl::Hidden);
 
 #ifndef NDEBUG
+static cl::opt<std::string>
+FilterDAGBasicBlockName("filter-view-dags", cl::Hidden,
+                        cl::desc("Only display the basic block whose name "
+                                 "matches this for all view-dags* options"));
 static cl::opt<bool>
 ViewDAGCombine1("view-dag-combine1-dags", cl::Hidden,
           cl::desc("Pop up a window to show dags before the first "

   std::string BlockName;
   int BlockNumber = -1;
   (void)BlockNumber;
+  bool MatchFilterBB = false; (void)MatchFilterBB;
 #ifdef NDEBUG
   if (ViewDAGCombine1 || ViewLegalizeTypesDAGs || ViewLegalizeDAGs ||
       ViewDAGCombine2 || ViewDAGCombineLT || ViewISelDAGs || ViewSchedDAGs ||

     BlockNumber = FuncInfo->MBB->getNumber();
     BlockName = MF->getName().str() + ":" +
                 FuncInfo->MBB->getBasicBlock()->getName().str();
+    MatchFilterBB = (!FilterDAGBasicBlockName.getValue().empty() &&
+                     FilterDAGBasicBlockName.getValue() ==
+                         FuncInfo->MBB->getBasicBlock()->getName().str());
   }
-  DEBUG(dbgs() << "Initial selection DAG: BB#" << BlockNumber
-        << " '" << BlockName << "'\n"; CurDAG->dump());
+  dbgs() << "Initial selection DAG: BB#" << BlockNumber
+        << " '" << BlockName << "'\n";
 
-  if (ViewDAGCombine1) CurDAG->viewGraph("dag-combine1 input for " + BlockName);
+  if (ViewDAGCombine1 && MatchFilterBB)
+    CurDAG->viewGraph("dag-combine1 input for " + BlockName);
 
   // Run the DAG combiner in pre-legalize mode.
   {

 
   // Second step, hack on the DAG until it only uses operations and types that
   // the target supports.
-  if (ViewLegalizeTypesDAGs) CurDAG->viewGraph("legalize-types input for " +
-                                               BlockName);
+  if (ViewLegalizeTypesDAGs && MatchFilterBB)
+    CurDAG->viewGraph("legalize-types input for " + BlockName);
 
   bool Changed;
   {

   CurDAG->NewNodesMustHaveLegalTypes = true;
 
   if (Changed) {
-    if (ViewDAGCombineLT)
+    if (ViewDAGCombineLT && MatchFilterBB)
       CurDAG->viewGraph("dag-combine-lt input for " + BlockName);
 
     // Run the DAG combiner in post-type-legalize mode.

       CurDAG->LegalizeTypes();
     }
 
-    if (ViewDAGCombineLT)
+    if (ViewDAGCombineLT && MatchFilterBB)
       CurDAG->viewGraph("dag-combine-lv input for " + BlockName);
 
     // Run the DAG combiner in post-type-legalize mode.

           << BlockNumber << " '" << BlockName << "'\n"; CurDAG->dump());
   }
 
-  if (ViewLegalizeDAGs) CurDAG->viewGraph("legalize input for " + BlockName);
+  if (ViewLegalizeDAGs && MatchFilterBB)
+    CurDAG->viewGraph("legalize input for " + BlockName);
 
   {
     NamedRegionTimer T("DAG Legalization", GroupName, TimePassesIsEnabled);

   DEBUG(dbgs() << "Legalized selection DAG: BB#" << BlockNumber
         << " '" << BlockName << "'\n"; CurDAG->dump());
 
-  if (ViewDAGCombine2) CurDAG->viewGraph("dag-combine2 input for " + BlockName);
+  if (ViewDAGCombine2 && MatchFilterBB)
+    CurDAG->viewGraph("dag-combine2 input for " + BlockName);
 
   // Run the DAG combiner in post-legalize mode.
   {

   if (OptLevel != CodeGenOpt::None)
     ComputeLiveOutVRegInfo();
 
-  if (ViewISelDAGs) CurDAG->viewGraph("isel input for " + BlockName);
+  if (ViewISelDAGs && MatchFilterBB)
+    CurDAG->viewGraph("isel input for " + BlockName);
 
   // Third, instruction select all of the operations to machine code, adding the
   // code to the MachineBasicBlock.

   DEBUG(dbgs() << "Selected selection DAG: BB#" << BlockNumber
         << " '" << BlockName << "'\n"; CurDAG->dump());
 
-  if (ViewSchedDAGs) CurDAG->viewGraph("scheduler input for " + BlockName);
+  if (ViewSchedDAGs && MatchFilterBB)
+    CurDAG->viewGraph("scheduler input for " + BlockName);
 
   // Schedule machine code.
   ScheduleDAGSDNodes *Scheduler = CreateScheduler();

     Scheduler->Run(CurDAG, FuncInfo->MBB);
   }
 
-  if (ViewSUnitDAGs) Scheduler->viewGraph();
+  if (ViewSUnitDAGs && MatchFilterBB) Scheduler->viewGraph();
 
   // Emit machine code to BB.  This can change 'BB' to the last block being
   // inserted into.