a52b9102d1
If both an order file and a call graph profile are present, the edges of the
call graph which use symbols present in the order file are not used. All of
the symbols in the order file will appear at the beginning of the section just
as they do currently. In other words, the highest priority derived from the
call graph will be below the lowest priority derived from the order file.
Practically, this change renames CallGraphSort.{h,cpp} to SectionPriorities.{h,cpp},
and most order file and call graph profile related code is moved into the new
file to reduce duplication.
Differential Revision: https://reviews.llvm.org/D117354
57 lines
2.2 KiB
C++
57 lines
2.2 KiB
C++
//===- SectionPriorities.h --------------------------------------*- C++ -*-===//
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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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#ifndef LLD_MACHO_SECTION_PRIORITIES_H
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#define LLD_MACHO_SECTION_PRIORITIES_H
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#include "InputSection.h"
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#include "llvm/ADT/DenseMap.h"
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namespace lld {
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namespace macho {
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// Reads every input section's call graph profile, and combines them into
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// config->callGraphProfile. If an order file is present, any edges where one
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// or both of the vertices are specified in the order file are discarded.
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void extractCallGraphProfile();
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// Reads the order file at `path` into config->priorities.
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//
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// An order file has one entry per line, in the following format:
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//
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// <cpu>:<object file>:<symbol name>
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//
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// <cpu> and <object file> are optional. If not specified, then that entry
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// matches any symbol of that name. Parsing this format is not quite
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// straightforward because the symbol name itself can contain colons, so when
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// encountering a colon, we consider the preceding characters to decide if it
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// can be a valid CPU type or file path.
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//
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// If a symbol is matched by multiple entries, then it takes the lowest-ordered
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// entry (the one nearest to the front of the list.)
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//
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// The file can also have line comments that start with '#'.
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void parseOrderFile(StringRef path);
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// Returns layout priorities for some or all input sections. Sections are laid
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// out in decreasing order; that is, a higher priority section will be closer
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// to the beginning of its output section.
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//
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// If either an order file or a call graph profile are present, this is used
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// as the source of priorities. If both are present, the order file takes
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// precedence, but the call graph profile is still used for symbols that don't
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// appear in the order file. If neither is present, an empty map is returned.
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//
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// Each section gets assigned the priority of the highest-priority symbol it
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// contains.
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llvm::DenseMap<const InputSection *, size_t> buildInputSectionPriorities();
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} // namespace macho
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} // namespace lld
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#endif
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