llvm-capstone/lld/MachO/UnwindInfoSection.h
Jez Ng 5112035751 [lld-macho] Emit LSDA info in compact unwind
The LSDA pointers are encoded as offsets from the image base,
and arranged in one big contiguous array. Each second-level page records
the offset within that LSDA array which corresponds to the LSDA for its
first CU entry.

Reviewed By: clayborg

Differential Revision: https://reviews.llvm.org/D95810
2021-02-08 13:48:00 -05:00

86 lines
2.5 KiB
C++

//===- UnwindInfoSection.h ------------------------------------------------===//
//
// 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_UNWIND_INFO_H
#define LLD_MACHO_UNWIND_INFO_H
#include "MergedOutputSection.h"
#include "SyntheticSections.h"
#include "mach-o/compact_unwind_encoding.h"
#include "llvm/ADT/DenseMap.h"
#include <vector>
// In 2020, we mostly care about 64-bit targets: x86_64 and arm64
struct CompactUnwindEntry64 {
uint64_t functionAddress;
uint32_t functionLength;
compact_unwind_encoding_t encoding;
uint64_t personality;
uint64_t lsda;
};
// FIXME(gkm): someday we might care about 32-bit targets: x86 & arm
struct CompactUnwindEntry32 {
uint32_t functionAddress;
uint32_t functionLength;
compact_unwind_encoding_t encoding;
uint32_t personality;
uint32_t lsda;
};
namespace lld {
namespace macho {
class UnwindInfoSection : public SyntheticSection {
public:
UnwindInfoSection();
uint64_t getSize() const override { return unwindInfoSize; }
bool isNeeded() const override;
void finalize() override;
void writeTo(uint8_t *buf) const override;
void setCompactUnwindSection(MergedOutputSection *cuSection) {
compactUnwindSection = cuSection;
}
using EncodingMap = llvm::DenseMap<compact_unwind_encoding_t, size_t>;
struct SecondLevelPage {
uint32_t kind;
size_t entryIndex;
size_t entryCount;
size_t byteCount;
std::vector<compact_unwind_encoding_t> localEncodings;
EncodingMap localEncodingIndexes;
};
private:
std::vector<std::pair<compact_unwind_encoding_t, size_t>> commonEncodings;
EncodingMap commonEncodingIndexes;
// Indices of personality functions within the GOT.
std::vector<uint32_t> personalities;
std::vector<unwind_info_section_header_lsda_index_entry> lsdaEntries;
// Map of function offset (from the image base) to an index within the LSDA
// array.
llvm::DenseMap<uint32_t, uint32_t> functionToLsdaIndex;
std::vector<CompactUnwindEntry64> cuVector;
std::vector<CompactUnwindEntry64 *> cuPtrVector;
std::vector<SecondLevelPage> secondLevelPages;
MergedOutputSection *compactUnwindSection = nullptr;
uint64_t level2PagesOffset = 0;
uint64_t unwindInfoSize = 0;
};
void prepareCompactUnwind(InputSection *isec);
} // namespace macho
} // namespace lld
#endif