[llvm] [BlockFrequency] Moves block printing function to Support to avoid depending on Analysis. (PR #75506)

[Micah Weston via llvm-commits]

https://github.com/red1bluelost created https://github.com/llvm/llvm-project/pull/75506

This patch just moves the `printBlockFreqImpl` from Analysis to Support so that it is accessible for programs which do not want to depend on Analysis library. Also renames the method to `printRelativeBlockFreq` so that it fits better as a standalone function.

It would be useful to reuse the same pretty printing functionality in areas that do not link directly with Analysis. My motivating use it within patches for PGOAnalysisMap being emitted within llvm-readobj and llvm-objdump. The readobj use case is at the following link where it would optionally pretty print the block frequency from the PGOAnalysisMap. https://github.com/red1bluelost/llvm-project/blob/eb20d0e04e8bd47bca6f89ffaf412f83a76ffcc9/llvm/tools/llvm-readobj/ELFDumper.cpp#L7526-L7530

>From b1c9936cae6fd7781dca6e0b0fe1496a337e623b Mon Sep 17 00:00:00 2001
From: Micah Weston <micahsweston at gmail.com>
Date: Thu, 7 Dec 2023 09:55:00 -0500
Subject: [PATCH] [BlockFrequency] Moves the block printing function to support
 to use without depending on Analysis.

---
 .../llvm/Analysis/BlockFrequencyInfoImpl.h     |  3 ---
 llvm/include/llvm/Support/BlockFrequency.h     |  4 ++++
 llvm/lib/Analysis/BlockFrequencyInfo.cpp       |  2 +-
 llvm/lib/Analysis/BlockFrequencyInfoImpl.cpp   | 15 ---------------
 llvm/lib/CodeGen/MachineBlockFrequencyInfo.cpp |  2 +-
 llvm/lib/Support/BlockFrequency.cpp            | 18 ++++++++++++++++++
 6 files changed, 24 insertions(+), 20 deletions(-)

diff --git a/llvm/include/llvm/Analysis/BlockFrequencyInfoImpl.h b/llvm/include/llvm/Analysis/BlockFrequencyInfoImpl.h
index 0c05be0b9b8cdf..0f22bc2745126c 100644
--- a/llvm/include/llvm/Analysis/BlockFrequencyInfoImpl.h
+++ b/llvm/include/llvm/Analysis/BlockFrequencyInfoImpl.h
@@ -539,9 +539,6 @@ class BlockFrequencyInfoImplBase {
   }
 };
 
-void printBlockFreqImpl(raw_ostream &OS, BlockFrequency EntryFreq,
-                        BlockFrequency Freq);
-
 namespace bfi_detail {
 
 template <class BlockT> struct TypeMap {};
diff --git a/llvm/include/llvm/Support/BlockFrequency.h b/llvm/include/llvm/Support/BlockFrequency.h
index 8b172ee486aab8..aeab99615a951a 100644
--- a/llvm/include/llvm/Support/BlockFrequency.h
+++ b/llvm/include/llvm/Support/BlockFrequency.h
@@ -19,6 +19,7 @@
 
 namespace llvm {
 
+class raw_ostream;
 class BranchProbability;
 
 // This class represents Block Frequency as a 64-bit value.
@@ -119,6 +120,9 @@ class BlockFrequency {
   }
 };
 
+void printRelativeBlockFreq(raw_ostream &OS, BlockFrequency EntryFreq,
+                            BlockFrequency Freq);
+
 } // namespace llvm
 
 #endif
diff --git a/llvm/lib/Analysis/BlockFrequencyInfo.cpp b/llvm/lib/Analysis/BlockFrequencyInfo.cpp
index 96c9bfa0e372ce..ebad8388cbe410 100644
--- a/llvm/lib/Analysis/BlockFrequencyInfo.cpp
+++ b/llvm/lib/Analysis/BlockFrequencyInfo.cpp
@@ -284,7 +284,7 @@ void BlockFrequencyInfo::verifyMatch(BlockFrequencyInfo &Other) const {
 Printable llvm::printBlockFreq(const BlockFrequencyInfo &BFI,
                                BlockFrequency Freq) {
   return Printable([&BFI, Freq](raw_ostream &OS) {
-    printBlockFreqImpl(OS, BFI.getEntryFreq(), Freq);
+    printRelativeBlockFreq(OS, BFI.getEntryFreq(), Freq);
   });
 }
 
diff --git a/llvm/lib/Analysis/BlockFrequencyInfoImpl.cpp b/llvm/lib/Analysis/BlockFrequencyInfoImpl.cpp
index ae08d56ef098a7..9f6e53ba15b6a6 100644
--- a/llvm/lib/Analysis/BlockFrequencyInfoImpl.cpp
+++ b/llvm/lib/Analysis/BlockFrequencyInfoImpl.cpp
@@ -634,21 +634,6 @@ BlockFrequencyInfoImplBase::getLoopName(const LoopData &Loop) const {
   return getBlockName(Loop.getHeader()) + (Loop.isIrreducible() ? "**" : "*");
 }
 
-void llvm::printBlockFreqImpl(raw_ostream &OS, BlockFrequency EntryFreq,
-                              BlockFrequency Freq) {
-  if (Freq == BlockFrequency(0)) {
-    OS << "0";
-    return;
-  }
-  if (EntryFreq == BlockFrequency(0)) {
-    OS << "<invalid BFI>";
-    return;
-  }
-  Scaled64 Block(Freq.getFrequency(), 0);
-  Scaled64 Entry(EntryFreq.getFrequency(), 0);
-  OS << Block / Entry;
-}
-
 void IrreducibleGraph::addNodesInLoop(const BFIBase::LoopData &OuterLoop) {
   Start = OuterLoop.getHeader();
   Nodes.reserve(OuterLoop.Nodes.size());
diff --git a/llvm/lib/CodeGen/MachineBlockFrequencyInfo.cpp b/llvm/lib/CodeGen/MachineBlockFrequencyInfo.cpp
index 7ee72e21442630..cbebdd87398e4b 100644
--- a/llvm/lib/CodeGen/MachineBlockFrequencyInfo.cpp
+++ b/llvm/lib/CodeGen/MachineBlockFrequencyInfo.cpp
@@ -280,7 +280,7 @@ BlockFrequency MachineBlockFrequencyInfo::getEntryFreq() const {
 Printable llvm::printBlockFreq(const MachineBlockFrequencyInfo &MBFI,
                                BlockFrequency Freq) {
   return Printable([&MBFI, Freq](raw_ostream &OS) {
-    printBlockFreqImpl(OS, MBFI.getEntryFreq(), Freq);
+    printRelativeBlockFreq(OS, MBFI.getEntryFreq(), Freq);
   });
 }
 
diff --git a/llvm/lib/Support/BlockFrequency.cpp b/llvm/lib/Support/BlockFrequency.cpp
index 329f1e12cdc29b..9bb48425ae89ec 100644
--- a/llvm/lib/Support/BlockFrequency.cpp
+++ b/llvm/lib/Support/BlockFrequency.cpp
@@ -13,6 +13,8 @@
 #include "llvm/Support/BlockFrequency.h"
 #include "llvm/Support/BranchProbability.h"
 #include "llvm/Support/MathExtras.h"
+#include "llvm/Support/ScaledNumber.h"
+#include "llvm/Support/raw_ostream.h"
 
 using namespace llvm;
 
@@ -45,3 +47,19 @@ std::optional<BlockFrequency> BlockFrequency::mul(uint64_t Factor) const {
     return {};
   return BlockFrequency(ResultFrequency);
 }
+
+void llvm::printRelativeBlockFreq(raw_ostream &OS, BlockFrequency EntryFreq,
+                              BlockFrequency Freq) {
+  if (Freq == BlockFrequency(0)) {
+    OS << "0";
+    return;
+  }
+  if (EntryFreq == BlockFrequency(0)) {
+    OS << "<invalid BFI>";
+    return;
+  }
+  ScaledNumber<uint64_t> Block(Freq.getFrequency(), 0);
+  ScaledNumber<uint64_t> Entry(EntryFreq.getFrequency(), 0);
+  OS << Block / Entry;
+}
+