[lld] [lld][ELF] Extend profile guided function ordering to ELF binaries (PR #117514)

[Fangrui Song via llvm-commits]

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@@ -0,0 +1,71 @@
+//===- BPSectionOrderer.cpp--------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "BPSectionOrderer.h"
+#include "Config.h"
+#include "InputFiles.h"
+#include "InputSection.h"
+#include "lld/Common/CommonLinkerContext.h"
+#include "lld/Common/SectionOrderer.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/Support/BalancedPartitioning.h"
+#include "llvm/Support/TimeProfiler.h"
+
+#include "SymbolTable.h"
+#include "Symbols.h"
+
+using namespace llvm;
+using namespace lld::elf;
+
+llvm::DenseMap<const lld::elf::InputSectionBase *, int>
+lld::elf::runBalancedPartitioning(Ctx &ctx, llvm::StringRef profilePath,
+                                  bool forFunctionCompression,
+                                  bool forDataCompression,
+                                  bool compressionSortStartupFunctions,
+                                  bool verbose) {
+  size_t highestAvailablePriority = std::numeric_limits<int>::max();
+  SmallVector<lld::BPSectionBase *> sections;
+
+  for (Symbol *sym : ctx.symtab->getSymbols()) {
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MaskRay wrote:

Needs a comment about what `sections` is

https://github.com/llvm/llvm-project/pull/117514