fd609e5d33
Add --bp-compression-sort-section=<glob>[=<layout_priority>[=<match_priority>]] to let users split input sections into multiple compression groups, run balanced partitioning independently per group, and leave out sections that are poor candidates for BP. This replaces the old coarse --bp-compression-sort with a more explicit, user-controlled one. In ELF, the glob matches input section names (.text.unlikely.cold1). In Mach-O, it matches the concatenated segment+section name (__TEXT__text). layout_priority controls group placement in the final layout. match_priority resolves conflicts when multiple globs match the same section: explicit priority beats positional matching, and among positional specs the last match wins. A CRTP hook getCompressionSubgroupKey() allows backends to further subdivide glob groups into independent BP instances. This allows Mach-O backend to separate cold functions via N_COLD_FUNC in the future. The deprecated --bp-compression-sort option keeps its existing function/data behavior by assigning sections to fixed legacy groups.
39 lines
1.4 KiB
C++
39 lines
1.4 KiB
C++
//===- BPSectionOrderer.h -------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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///
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/// This file uses Balanced Partitioning to order sections to improve startup
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/// time and compressed size.
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///
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//===----------------------------------------------------------------------===//
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#ifndef LLD_MACHO_BPSECTION_ORDERER_H
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#define LLD_MACHO_BPSECTION_ORDERER_H
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#include "lld/Common/BPSectionOrdererBase.h"
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#include "llvm/ADT/ArrayRef.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/StringRef.h"
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namespace lld::macho {
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class InputSection;
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/// Run Balanced Partitioning to find the optimal function and data order to
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/// improve startup time and compressed size.
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///
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/// It is important that .subsections_via_symbols is used to ensure functions
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/// and data are in their own sections and thus can be reordered.
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llvm::DenseMap<const InputSection *, int> runBalancedPartitioning(
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llvm::StringRef profilePath,
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llvm::ArrayRef<BPCompressionSortSpec> compressionSortSpecs,
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bool forFunctionCompression, bool forDataCompression,
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bool compressionSortStartupFunctions, bool verbose);
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} // namespace lld::macho
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#endif
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