llvm-capstone/lld/MachO/ExportTrie.h
Jez Ng 7bbdbacd00 [lld-macho] Use export trie instead of symtab when linking against dylibs
Summary:
This allows us to link against stripped dylibs. Moreover, it's simply
more correct: The symbol table includes symbols that the dylib uses but
doesn't export.

This temporarily regresses our ability to do lazy symbol binding because
dyld_stub_binder isn't in libSystem's export trie. Rather, it is in one
of the sub-libraries libSystem re-exports. (This doesn't affect our
tests since we are mocking out dyld_stub_binder there.) A follow-up diff
will address this by adding support for sub-libraries.

Depends on D79114.

Reviewers: ruiu, pcc, MaskRay, smeenai, alexshap, gkm, Ktwu, christylee

Subscribers: mgorny, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D79226
2020-05-09 20:56:22 -07:00

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1.2 KiB
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//===- ExportTrie.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_EXPORT_TRIE_H
#define LLD_MACHO_EXPORT_TRIE_H
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/STLExtras.h"
#include <vector>
namespace lld {
namespace macho {
struct TrieNode;
class Symbol;
class TrieBuilder {
public:
void addSymbol(const Symbol &sym) { exported.push_back(&sym); }
// Returns the size in bytes of the serialized trie.
size_t build();
void writeTo(uint8_t *buf) const;
private:
TrieNode *makeNode();
void sortAndBuild(llvm::MutableArrayRef<const Symbol *> vec, TrieNode *node,
size_t lastPos, size_t pos);
std::vector<const Symbol *> exported;
std::vector<TrieNode *> nodes;
};
using TrieEntryCallback =
llvm::function_ref<void(const llvm::Twine & /*name*/, uint64_t /*flags*/)>;
void parseTrie(const uint8_t *buf, size_t size, const TrieEntryCallback &);
} // namespace macho
} // namespace lld
#endif