[NewPM] Print function/SCC size with -debug-pass-manager

[aeubanks]

Summary

This is helpful for debugging issues with very large functions or SCC.
Also helpful when function names are very large and it's hard to tell the number of nodes in an SCC.

[aeubanks]

ping

[hans]

Seems useful to me.

llvm/lib/Passes/StandardInstrumentations.cpp

PIC.registerBeforeSkippedPassCallback([this, SpecialPasses](StringRef PassID,
 
     print() << "Skipping pass: " << PassID << " on " << getIRName(IR) << "\n";
   });
   PIC.registerBeforeNonSkippedPassCallback([this, SpecialPasses](
                                                StringRef PassID, Any IR) {
     if (isSpecialPass(PassID, SpecialPasses))
       return;
 
-    print() << "Running pass: " << PassID << " on " << getIRName(IR) << "\n";
+    auto &OS = print();
+    OS << "Running pass: " << PassID << " on " << getIRName(IR);
+    if (any_isa<const Function *>(IR)) {
+      unsigned Count = any_cast<const Function *>(IR)->getInstructionCount();
+      OS << " (" << Count << " instruction";
+      if (Count != 1)
+        OS << 's';
+      OS << ')';
+    } else if (any_isa<const LazyCallGraph::SCC *>(IR)) {
+      int Count = any_cast<const LazyCallGraph::SCC *>(IR)->size();
+      OS << " (" << Count << " node";
+      if (Count != 1)
+        OS << 's';
+      OS << ')';
+    }
+    OS << "\n";
     Indent += 2;
   });
   PIC.registerAfterPassCallback(
       [this, SpecialPasses](StringRef PassID, Any IR,
                             const PreservedAnalyses &) {
         if (isSpecialPass(PassID, SpecialPasses))
           return;
 

llvm/test/Other/print-function-size.ll

+; RUN: opt -S -debug-pass-manager -passes=no-op-function < %s 2>&1 | FileCheck %s
+
+; CHECK: Running pass: NoOpFunctionPass on f (3 instructions)
+; CHECK: Running pass: NoOpFunctionPass on g (1 instruction)
+
+define i32 @f(i32 %i) {
+  %a = add i32 %i, 1
+  %b = add i32 %a, 1
+  ret i32 %b
+}
+
+define i32 @g(i32 %i) {
+  ret i32 0
+}

llvm/test/Other/print-scc-size.ll

+; RUN: opt -S -debug-pass-manager -passes=no-op-cgscc < %s 2>&1 | FileCheck %s
+
+; CHECK: Running pass: NoOpCGSCCPass on (f) (1 node)
+; CHECK: Running pass: NoOpCGSCCPass on (g, h) (2 nodes)
+
+define void @f() {
+  ret void
+}
+
+define void @g() {
+  call void @h()
+  ret void
+}
+
+define void @h() {
+  call void @g()
+  ret void
+}