[LLVM] Add color to SDNode ID's when dumping

[jroelofs]

This is especially helpful for the recursive 'Cannot select:' dumps, where colors help distinguish nodes at a quick glance.

[llvmbot]

@llvm/pr-subscribers-llvm-selectiondag

Author: Jon Roelofs (jroelofs)

Changes

This is especially helpful for the recursive 'Cannot select:' dumps, where colors help distinguish nodes at a quick glance.

---

Full diff: https://github.com/llvm/llvm-project/pull/141295.diff

2 Files Affected:

• (modified) llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp (+7)
• (modified) llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp (+2)

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
index 803894e298dd5..ee4297f3ad8ce 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
@@ -606,7 +606,14 @@ const char *SDNode::getIndexedModeName(ISD::MemIndexedMode AM) {
 static Printable PrintNodeId(const SDNode &Node) {
   return Printable([&Node](raw_ostream &OS) {
 #ifndef NDEBUG
+    static const raw_ostream::Colors Color[] = {
+        raw_ostream::BLACK,  raw_ostream::RED,  raw_ostream::GREEN,
+        raw_ostream::YELLOW, raw_ostream::BLUE, raw_ostream::MAGENTA,
+        raw_ostream::CYAN,
+    };
+    OS.changeColor(Color[Node.PersistentId % std::size(Color)]);
     OS << 't' << Node.PersistentId;
+    OS.resetColor();
 #else
     OS << (const void*)&Node;
 #endif
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 4bdb8e68c0d32..c6b45a6042746 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -4415,6 +4415,8 @@ void SelectionDAGISel::CannotYetSelect(SDNode *N) {
   raw_string_ostream Msg(msg);
   Msg << "Cannot select: ";
 
+  Msg.enable_colors(errs().has_colors());
+
   if (N->getOpcode() != ISD::INTRINSIC_W_CHAIN &&
       N->getOpcode() != ISD::INTRINSIC_WO_CHAIN &&
       N->getOpcode() != ISD::INTRINSIC_VOID) {

[jroelofs]

[fpetrogalli]

If I look at this dump I see:

1. The dump uses the same colors for t1 and t8, and t10 and t3.
2. The nodes t8, t3 and t5 should not be printed at all [*]

Now I have two things that confuse me, instead of just one.

But this is my personal preference, if other people like the feature, I will not stop it.

[*] Why are these nodes even printed is a separate issue that I think it is worth pointing out. They are made explicit in the nodes that use them!

[jroelofs]

1. The dump uses the same colors for t1 and t8, and t10 and t3.

I think this is unavoidable. These dumps often have way more nodes in them than we have terminal colors available. An astute reader should quickly see that nodes with different colors have different IDs, but that nodes with the same color still need a little more careful of a look.

[fpetrogalli]

@jroelofs - you convinced me - let's get this in :)

[topperc]

LGTM