cc88a5e615
--order_file, call graph profile, and BalancedPartitioning currently build the section order vector by decreasing priority (from SIZE_MAX to 0). However, it's conventional to use an increasing key (see OutputSection::inputOrder). Switch to increasing priorities, remove the global variable highestAvailablePriority, and remove the highestAvailablePriority parameter from BPSectionOrderer. Change size_t to int. This improves consistenty with the ELF and COFF ports. The ELF port utilizes negative priorities for --symbol-ordering-file and call graph profile, and non-negative priorities for --shuffle-sections (no Mach-O counterpart yet). Pull Request: https://github.com/llvm/llvm-project/pull/121727
78 lines
3.1 KiB
C++
78 lines
3.1 KiB
C++
//===- SectionPriorities.h --------------------------------------*- 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
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLD_MACHO_SECTION_PRIORITIES_H
|
|
#define LLD_MACHO_SECTION_PRIORITIES_H
|
|
|
|
#include "InputSection.h"
|
|
#include "llvm/ADT/DenseMap.h"
|
|
#include "llvm/ADT/MapVector.h"
|
|
|
|
namespace lld::macho {
|
|
|
|
using SectionPair = std::pair<const InputSection *, const InputSection *>;
|
|
|
|
class PriorityBuilder {
|
|
public:
|
|
// Reads every input section's call graph profile, and combines them into
|
|
// callGraphProfile. If an order file is present, any edges where one or both
|
|
// of the vertices are specified in the order file are discarded.
|
|
void extractCallGraphProfile();
|
|
|
|
// Reads the order file at `path` into config->priorities.
|
|
//
|
|
// An order file has one entry per line, in the following format:
|
|
//
|
|
// <cpu>:<object file>:<symbol name>
|
|
//
|
|
// <cpu> and <object file> are optional. If not specified, then that entry
|
|
// matches any symbol of that name. Parsing this format is not quite
|
|
// straightforward because the symbol name itself can contain colons, so when
|
|
// encountering a colon, we consider the preceding characters to decide if it
|
|
// can be a valid CPU type or file path.
|
|
//
|
|
// If a symbol is matched by multiple entries, then it takes the
|
|
// lowest-ordered entry (the one nearest to the front of the list.)
|
|
//
|
|
// The file can also have line comments that start with '#'.
|
|
void parseOrderFile(StringRef path);
|
|
|
|
// Returns layout priorities for some or all input sections. Sections are laid
|
|
// out in decreasing order; that is, a higher priority section will be closer
|
|
// to the beginning of its output section.
|
|
//
|
|
// If either an order file or a call graph profile are present, this is used
|
|
// as the source of priorities. If both are present, the order file takes
|
|
// precedence, but the call graph profile is still used for symbols that don't
|
|
// appear in the order file. If neither is present, an empty map is returned.
|
|
//
|
|
// Each section gets assigned the priority of the highest-priority symbol it
|
|
// contains.
|
|
llvm::DenseMap<const InputSection *, int> buildInputSectionPriorities();
|
|
|
|
private:
|
|
// The symbol with the smallest priority should be ordered first in the output
|
|
// section (modulo input section contiguity constraints).
|
|
struct SymbolPriorityEntry {
|
|
// The priority given to a matching symbol, regardless of which object file
|
|
// it originated from.
|
|
int anyObjectFile = 0;
|
|
// The priority given to a matching symbol from a particular object file.
|
|
llvm::DenseMap<llvm::StringRef, int> objectFiles;
|
|
};
|
|
|
|
std::optional<int> getSymbolPriority(const Defined *sym);
|
|
llvm::DenseMap<llvm::StringRef, SymbolPriorityEntry> priorities;
|
|
llvm::MapVector<SectionPair, uint64_t> callGraphProfile;
|
|
};
|
|
|
|
extern PriorityBuilder priorityBuilder;
|
|
} // namespace lld::macho
|
|
|
|
#endif
|