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swift-mirror/include/swift/Reflection/ReflectionContext.h
tbkka 3c8fde7885 Implement MultiPayloadEnum support for projectEnumValue (#30635) 
This code rearchitects and simplifies the projectEnumValue support by
introducing a new `TypeInfo` subclass for each kind of enum, including trivial,
no-payload, single-payload, and three different classes for multi-payload enums:

* "UnsupportedEnum" that we don't understand.  This returns "don't know" answers for all requests in cases where the runtime lacks enough information to accurately handle a particular enum.

* MP Enums that only use a separate tag value.  This includes generic enums and other dynamic layouts, as well as enums whose payloads have no spare bits.

* MP Enums that use spare bits, possibly in addition to a separate tag.  This logic can only be used, of course, if we can in fact compute a spare bit mask that agrees with the compiler.

The final challenge is to choose one of the above three handlings for every MPE.  Currently, we do not have an accurate source of information for the spare bit mask, so we never choose the third option above.  We use the second option for dynamic MPE layouts (including generics) and the first for everything else.

TODO: Once we can arrange for the compiler to expose spare bit mask data, we'll be able to use that to drive more MPE cases.
2020-03-31 15:12:44 -07:00

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//===--- ReflectionContext.h - Swift Type Reflection Context ----*- C++ -*-===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// Implements the context for reflection of values in the address space of a
// remote process.
//
//===----------------------------------------------------------------------===//
#ifndef SWIFT_REFLECTION_REFLECTIONCONTEXT_H
#define SWIFT_REFLECTION_REFLECTIONCONTEXT_H
#include "llvm/BinaryFormat/COFF.h"
#include "llvm/BinaryFormat/MachO.h"
#include "llvm/BinaryFormat/ELF.h"
#include "llvm/Object/COFF.h"
#include "swift/ABI/Enum.h"
#include "swift/Remote/MemoryReader.h"
#include "swift/Remote/MetadataReader.h"
#include "swift/Reflection/Records.h"
#include "swift/Reflection/TypeLowering.h"
#include "swift/Reflection/TypeRef.h"
#include "swift/Reflection/TypeRefBuilder.h"
#include "swift/Runtime/Unreachable.h"
#include <set>
#include <vector>
#include <unordered_map>
#include <utility>
namespace {
template <unsigned PointerSize> struct MachOTraits;
template <> struct MachOTraits<4> {
using Header = const struct llvm::MachO::mach_header;
using SegmentCmd = const struct llvm::MachO::segment_command;
using Section = const struct llvm::MachO::section;
static constexpr size_t MagicNumber = llvm::MachO::MH_MAGIC;
};
template <> struct MachOTraits<8> {
using Header = const struct llvm::MachO::mach_header_64;
using SegmentCmd = const struct llvm::MachO::segment_command_64;
using Section = const struct llvm::MachO::section_64;
static constexpr size_t MagicNumber = llvm::MachO::MH_MAGIC_64;
};
template <unsigned char ELFClass> struct ELFTraits;
template <> struct ELFTraits<llvm::ELF::ELFCLASS32> {
using Header = const struct llvm::ELF::Elf32_Ehdr;
using Section = const struct llvm::ELF::Elf32_Shdr;
using Offset = llvm::ELF::Elf32_Off;
using Size = llvm::ELF::Elf32_Word;
static constexpr unsigned char ELFClass = llvm::ELF::ELFCLASS32;
};
template <> struct ELFTraits<llvm::ELF::ELFCLASS64> {
using Header = const struct llvm::ELF::Elf64_Ehdr;
using Section = const struct llvm::ELF::Elf64_Shdr;
using Offset = llvm::ELF::Elf64_Off;
using Size = llvm::ELF::Elf64_Xword;
static constexpr unsigned char ELFClass = llvm::ELF::ELFCLASS64;
};
} // namespace
namespace swift {
namespace reflection {
using swift::remote::MemoryReader;
using swift::remote::RemoteAddress;
template <typename Runtime>
class ReflectionContext
: public remote::MetadataReader<Runtime, TypeRefBuilder> {
using super = remote::MetadataReader<Runtime, TypeRefBuilder>;
using super::readMetadata;
using super::readObjCClassName;
std::unordered_map<typename super::StoredPointer, const TypeInfo *> Cache;
/// All buffers we need to keep around long term. This will automatically free them
/// when this object is destroyed.
std::vector<MemoryReader::ReadBytesResult> savedBuffers;
std::vector<std::tuple<RemoteAddress, RemoteAddress>> imageRanges;
public:
using super::getBuilder;
using super::readDemanglingForContextDescriptor;
using super::readGenericArgFromMetadata;
using super::readIsaMask;
using super::readMetadataAndValueErrorExistential;
using super::readMetadataAndValueOpaqueExistential;
using super::readMetadataFromInstance;
using super::readTypeFromMetadata;
using typename super::StoredPointer;
explicit ReflectionContext(std::shared_ptr<MemoryReader> reader)
: super(std::move(reader), *this)
{}
ReflectionContext(const ReflectionContext &other) = delete;
ReflectionContext &operator=(const ReflectionContext &other) = delete;
MemoryReader &getReader() {
return *this->Reader;
}
unsigned getSizeOfHeapObject() {
// This must match sizeof(HeapObject) for the target.
return sizeof(StoredPointer) * 2;
}
template <typename T> bool readMachOSections(RemoteAddress ImageStart) {
auto Buf =
this->getReader().readBytes(ImageStart, sizeof(typename T::Header));
if (!Buf)
return false;
auto Header = reinterpret_cast<typename T::Header *>(Buf.get());
assert(Header->magic == T::MagicNumber && "invalid MachO file");
auto NumCommands = Header->sizeofcmds;
// The layout of the executable is such that the commands immediately follow
// the header.
auto CmdStartAddress =
RemoteAddress(ImageStart.getAddressData() + sizeof(typename T::Header));
uint32_t SegmentCmdHdrSize = sizeof(typename T::SegmentCmd);
uint64_t Offset = 0;
// Find the __TEXT segment.
typename T::SegmentCmd *Command = nullptr;
for (unsigned I = 0; I < NumCommands; ++I) {
auto CmdBuf = this->getReader().readBytes(
RemoteAddress(CmdStartAddress.getAddressData() + Offset),
SegmentCmdHdrSize);
auto CmdHdr = reinterpret_cast<typename T::SegmentCmd *>(CmdBuf.get());
if (strncmp(CmdHdr->segname, "__TEXT", sizeof(CmdHdr->segname)) == 0) {
Command = CmdHdr;
savedBuffers.push_back(std::move(CmdBuf));
break;
}
Offset += CmdHdr->cmdsize;
}
// No __TEXT segment, bail out.
if (!Command)
return false;
// Find the load command offset.
auto loadCmdOffset = ImageStart.getAddressData() + Offset + sizeof(typename T::Header);
// Read the load command.
auto LoadCmdAddress = reinterpret_cast<const char *>(loadCmdOffset);
auto LoadCmdBuf = this->getReader().readBytes(
RemoteAddress(LoadCmdAddress), sizeof(typename T::SegmentCmd));
auto LoadCmd = reinterpret_cast<typename T::SegmentCmd *>(LoadCmdBuf.get());
// The sections start immediately after the load command.
unsigned NumSect = LoadCmd->nsects;
auto SectAddress = reinterpret_cast<const char *>(loadCmdOffset) +
sizeof(typename T::SegmentCmd);
auto Sections = this->getReader().readBytes(
RemoteAddress(SectAddress), NumSect * sizeof(typename T::Section));
auto Slide = ImageStart.getAddressData() - Command->vmaddr;
std::string Prefix = "__swift5";
uint64_t RangeStart = UINT64_MAX;
uint64_t RangeEnd = UINT64_MAX;
auto SectionsBuf = reinterpret_cast<const char *>(Sections.get());
for (unsigned I = 0; I < NumSect; ++I) {
auto S = reinterpret_cast<typename T::Section *>(
SectionsBuf + (I * sizeof(typename T::Section)));
if (strncmp(S->sectname, Prefix.c_str(), strlen(Prefix.c_str())) != 0)
continue;
if (RangeStart == UINT64_MAX && RangeEnd == UINT64_MAX) {
RangeStart = S->addr + Slide;
RangeEnd = S->addr + S->size + Slide;
continue;
}
RangeStart = std::min(RangeStart, (uint64_t)S->addr + Slide);
RangeEnd = std::max(RangeEnd, (uint64_t)(S->addr + S->size + Slide));
// Keep the range rounded to 8 byte alignment on both ends so we don't
// introduce misaligned pointers mapping between local and remote
// address space.
RangeStart = RangeStart & ~7;
RangeEnd = RangeEnd + 7 & ~7;
}
if (RangeStart == UINT64_MAX && RangeEnd == UINT64_MAX)
return false;
auto SectBuf = this->getReader().readBytes(RemoteAddress(RangeStart),
RangeEnd - RangeStart);
auto findMachOSectionByName = [&](std::string Name)
-> std::pair<RemoteRef<void>, uint64_t> {
for (unsigned I = 0; I < NumSect; ++I) {
auto S = reinterpret_cast<typename T::Section *>(
SectionsBuf + (I * sizeof(typename T::Section)));
if (strncmp(S->sectname, Name.c_str(), strlen(Name.c_str())) != 0)
continue;
auto RemoteSecStart = S->addr + Slide;
auto SectBufData = reinterpret_cast<const char *>(SectBuf.get());
auto LocalSectStart =
reinterpret_cast<const char *>(SectBufData + RemoteSecStart - RangeStart);
auto StartRef = RemoteRef<void>(RemoteSecStart, LocalSectStart);
return {StartRef, S->size};
}
return {nullptr, 0};
};
auto FieldMdSec = findMachOSectionByName("__swift5_fieldmd");
auto AssocTySec = findMachOSectionByName("__swift5_assocty");
auto BuiltinTySec = findMachOSectionByName("__swift5_builtin");
auto CaptureSec = findMachOSectionByName("__swift5_capture");
auto TypeRefMdSec = findMachOSectionByName("__swift5_typeref");
auto ReflStrMdSec = findMachOSectionByName("__swift5_reflstr");
if (FieldMdSec.first == nullptr &&
AssocTySec.first == nullptr &&
BuiltinTySec.first == nullptr &&
CaptureSec.first == nullptr &&
TypeRefMdSec.first == nullptr &&
ReflStrMdSec.first == nullptr)
return false;
ReflectionInfo info = {
{FieldMdSec.first, FieldMdSec.second},
{AssocTySec.first, AssocTySec.second},
{BuiltinTySec.first, BuiltinTySec.second},
{CaptureSec.first, CaptureSec.second},
{TypeRefMdSec.first, TypeRefMdSec.second},
{ReflStrMdSec.first, ReflStrMdSec.second}};
this->addReflectionInfo(info);
// Find the __DATA segment.
for (unsigned I = 0; I < NumCommands; ++I) {
auto CmdBuf = this->getReader().readBytes(
RemoteAddress(CmdStartAddress.getAddressData() + Offset),
SegmentCmdHdrSize);
auto CmdHdr = reinterpret_cast<typename T::SegmentCmd *>(CmdBuf.get());
if (strncmp(CmdHdr->segname, "__DATA", sizeof(CmdHdr->segname)) == 0) {
auto DataSegmentEnd =
ImageStart.getAddressData() + CmdHdr->vmaddr + CmdHdr->vmsize;
assert(DataSegmentEnd > ImageStart.getAddressData() &&
"invalid range for __DATA");
imageRanges.push_back(
std::make_tuple(ImageStart, RemoteAddress(DataSegmentEnd)));
break;
}
Offset += CmdHdr->cmdsize;
}
savedBuffers.push_back(std::move(Buf));
savedBuffers.push_back(std::move(SectBuf));
savedBuffers.push_back(std::move(Sections));
return true;
}
bool readPECOFFSections(RemoteAddress ImageStart) {
auto DOSHdrBuf = this->getReader().readBytes(
ImageStart, sizeof(llvm::object::dos_header));
auto DOSHdr =
reinterpret_cast<const llvm::object::dos_header *>(DOSHdrBuf.get());
auto COFFFileHdrAddr = ImageStart.getAddressData() +
DOSHdr->AddressOfNewExeHeader +
sizeof(llvm::COFF::PEMagic);
auto COFFFileHdrBuf = this->getReader().readBytes(
RemoteAddress(COFFFileHdrAddr), sizeof(llvm::object::coff_file_header));
auto COFFFileHdr = reinterpret_cast<const llvm::object::coff_file_header *>(
COFFFileHdrBuf.get());
auto SectionTableAddr = COFFFileHdrAddr +
sizeof(llvm::object::coff_file_header) +
COFFFileHdr->SizeOfOptionalHeader;
auto SectionTableBuf = this->getReader().readBytes(
RemoteAddress(SectionTableAddr),
sizeof(llvm::object::coff_section) * COFFFileHdr->NumberOfSections);
auto findCOFFSectionByName = [&](llvm::StringRef Name)
-> std::pair<RemoteRef<void>, uint64_t> {
for (size_t i = 0; i < COFFFileHdr->NumberOfSections; ++i) {
const llvm::object::coff_section *COFFSec =
reinterpret_cast<const llvm::object::coff_section *>(
SectionTableBuf.get()) +
i;
llvm::StringRef SectionName =
(COFFSec->Name[llvm::COFF::NameSize - 1] == 0)
? COFFSec->Name
: llvm::StringRef(COFFSec->Name, llvm::COFF::NameSize);
if (SectionName != Name)
continue;
auto Addr = ImageStart.getAddressData() + COFFSec->VirtualAddress;
auto Buf = this->getReader().readBytes(RemoteAddress(Addr),
COFFSec->VirtualSize);
auto BufStart = Buf.get();
savedBuffers.push_back(std::move(Buf));
auto Begin = RemoteRef<void>(Addr, BufStart);
auto Size = COFFSec->VirtualSize;
// FIXME: This code needs to be cleaned up and updated
// to make it work for 32 bit platforms.
if (SectionName != ".sw5cptr" && SectionName != ".sw5bltn") {
Begin = Begin.atByteOffset(8);
Size -= 16;
}
return {Begin, Size};
}
return {nullptr, 0};
};
auto CaptureSec = findCOFFSectionByName(".sw5cptr");
auto TypeRefMdSec = findCOFFSectionByName(".sw5tyrf");
auto FieldMdSec = findCOFFSectionByName(".sw5flmd");
auto AssocTySec = findCOFFSectionByName(".sw5asty");
auto BuiltinTySec = findCOFFSectionByName(".sw5bltn");
auto ReflStrMdSec = findCOFFSectionByName(".sw5rfst");
if (FieldMdSec.first == nullptr &&
AssocTySec.first == nullptr &&
BuiltinTySec.first == nullptr &&
CaptureSec.first == nullptr &&
TypeRefMdSec.first == nullptr &&
ReflStrMdSec.first == nullptr)
return false;
ReflectionInfo Info = {
{FieldMdSec.first, FieldMdSec.second},
{AssocTySec.first, AssocTySec.second},
{BuiltinTySec.first, BuiltinTySec.second},
{CaptureSec.first, CaptureSec.second},
{TypeRefMdSec.first, TypeRefMdSec.second},
{ReflStrMdSec.first, ReflStrMdSec.second}};
this->addReflectionInfo(Info);
return true;
}
bool readPECOFF(RemoteAddress ImageStart) {
auto Buf = this->getReader().readBytes(ImageStart,
sizeof(llvm::object::dos_header));
if (!Buf)
return false;
auto DOSHdr = reinterpret_cast<const llvm::object::dos_header *>(Buf.get());
auto PEHeaderAddress =
ImageStart.getAddressData() + DOSHdr->AddressOfNewExeHeader;
Buf = this->getReader().readBytes(RemoteAddress(PEHeaderAddress),
sizeof(llvm::COFF::PEMagic));
if (!Buf)
return false;
if (memcmp(Buf.get(), llvm::COFF::PEMagic, sizeof(llvm::COFF::PEMagic)))
return false;
return readPECOFFSections(ImageStart);
}
template <typename T> bool readELFSections(RemoteAddress ImageStart) {
auto Buf =
this->getReader().readBytes(ImageStart, sizeof(typename T::Header));
auto Hdr = reinterpret_cast<const typename T::Header *>(Buf.get());
assert(Hdr->getFileClass() == T::ELFClass && "invalid ELF file class");
// From the header, grab informations about the section header table.
auto SectionHdrAddress = ImageStart.getAddressData() + Hdr->e_shoff;
auto SectionHdrNumEntries = Hdr->e_shnum;
auto SectionEntrySize = Hdr->e_shentsize;
// Collect all the section headers, we need them to look up the
// reflection sections (by name) and the string table.
std::vector<const typename T::Section *> SecHdrVec;
for (unsigned I = 0; I < SectionHdrNumEntries; ++I) {
auto SecBuf = this->getReader().readBytes(
RemoteAddress(SectionHdrAddress + (I * SectionEntrySize)),
SectionEntrySize);
if (!SecBuf)
return false;
auto SecHdr =
reinterpret_cast<const typename T::Section *>(SecBuf.get());
SecHdrVec.push_back(SecHdr);
}
// This provides quick access to the section header string table index.
// We also here handle the unlikely even where the section index overflows
// and it's just a pointer to secondary storage (SHN_XINDEX).
uint32_t SecIdx = Hdr->e_shstrndx;
if (SecIdx == llvm::ELF::SHN_XINDEX) {
assert(!SecHdrVec.empty() && "malformed ELF object");
SecIdx = SecHdrVec[0]->sh_link;
}
assert(SecIdx < SecHdrVec.size() && "malformed ELF object");
const typename T::Section *SecHdrStrTab = SecHdrVec[SecIdx];
typename T::Offset StrTabOffset = SecHdrStrTab->sh_offset;
typename T::Size StrTabSize = SecHdrStrTab->sh_size;
auto StrTabStart =
RemoteAddress(ImageStart.getAddressData() + StrTabOffset);
auto StrTabBuf = this->getReader().readBytes(StrTabStart, StrTabSize);
auto StrTab = reinterpret_cast<const char *>(StrTabBuf.get());
auto findELFSectionByName = [&](std::string Name)
-> std::pair<RemoteRef<void>, uint64_t> {
// Now for all the sections, find their name.
for (const typename T::Section *Hdr : SecHdrVec) {
uint32_t Offset = Hdr->sh_name;
auto SecName = std::string(StrTab + Offset);
if (SecName != Name)
continue;
auto SecStart =
RemoteAddress(ImageStart.getAddressData() + Hdr->sh_addr);
auto SecSize = Hdr->sh_size;
auto SecBuf = this->getReader().readBytes(SecStart, SecSize);
auto SecContents = RemoteRef<void>(SecStart.getAddressData(),
SecBuf.get());
savedBuffers.push_back(std::move(SecBuf));
return {SecContents, SecSize};
}
return {nullptr, 0};
};
auto FieldMdSec = findELFSectionByName("swift5_fieldmd");
auto AssocTySec = findELFSectionByName("swift5_assocty");
auto BuiltinTySec = findELFSectionByName("swift5_builtin");
auto CaptureSec = findELFSectionByName("swift5_capture");
auto TypeRefMdSec = findELFSectionByName("swift5_typeref");
auto ReflStrMdSec = findELFSectionByName("swift5_reflstr");
// We succeed if at least one of the sections is present in the
// ELF executable.
if (FieldMdSec.first == nullptr &&
AssocTySec.first == nullptr &&
BuiltinTySec.first == nullptr &&
CaptureSec.first == nullptr &&
TypeRefMdSec.first == nullptr &&
ReflStrMdSec.first == nullptr)
return false;
ReflectionInfo info = {
{FieldMdSec.first, FieldMdSec.second},
{AssocTySec.first, AssocTySec.second},
{BuiltinTySec.first, BuiltinTySec.second},
{CaptureSec.first, CaptureSec.second},
{TypeRefMdSec.first, TypeRefMdSec.second},
{ReflStrMdSec.first, ReflStrMdSec.second}};
this->addReflectionInfo(info);
savedBuffers.push_back(std::move(Buf));
return true;
}
bool readELF(RemoteAddress ImageStart) {
auto Buf =
this->getReader().readBytes(ImageStart, sizeof(llvm::ELF::Elf64_Ehdr));
// Read the header.
auto Hdr = reinterpret_cast<const llvm::ELF::Elf64_Ehdr *>(Buf.get());
if (!Hdr->checkMagic())
return false;
// Check if we have a ELFCLASS32 or ELFCLASS64
unsigned char FileClass = Hdr->getFileClass();
if (FileClass == llvm::ELF::ELFCLASS64) {
return readELFSections<ELFTraits<llvm::ELF::ELFCLASS64>>(ImageStart);
} else if (FileClass == llvm::ELF::ELFCLASS32) {
return readELFSections<ELFTraits<llvm::ELF::ELFCLASS32>>(ImageStart);
} else {
return false;
}
}
bool addImage(RemoteAddress ImageStart) {
// Read the first few bytes to look for a magic header.
auto Magic = this->getReader().readBytes(ImageStart, sizeof(uint32_t));
if (!Magic)
return false;
uint32_t MagicWord;
memcpy(&MagicWord, Magic.get(), sizeof(MagicWord));
// 32- and 64-bit Mach-O.
if (MagicWord == llvm::MachO::MH_MAGIC) {
return readMachOSections<MachOTraits<4>>(ImageStart);
}
if (MagicWord == llvm::MachO::MH_MAGIC_64) {
return readMachOSections<MachOTraits<8>>(ImageStart);
}
// PE. (This just checks for the DOS header; `readPECOFF` will further
// validate the existence of the PE header.)
auto MagicBytes = (const char*)Magic.get();
if (MagicBytes[0] == 'M' && MagicBytes[1] == 'Z') {
return readPECOFF(ImageStart);
}
// ELF.
if (MagicBytes[0] == llvm::ELF::ElfMagic[0]
&& MagicBytes[1] == llvm::ELF::ElfMagic[1]
&& MagicBytes[2] == llvm::ELF::ElfMagic[2]
&& MagicBytes[3] == llvm::ELF::ElfMagic[3]) {
return readELF(ImageStart);
}
// We don't recognize the format.
return false;
}
void addReflectionInfo(ReflectionInfo I) {
getBuilder().addReflectionInfo(I);
}
bool ownsObject(RemoteAddress ObjectAddress) {
auto MetadataAddress = readMetadataFromInstance(ObjectAddress.getAddressData());
if (!MetadataAddress)
return true;
return ownsAddress(RemoteAddress(*MetadataAddress));
}
/// Returns true if the address falls within a registered image.
bool ownsAddress(RemoteAddress Address) {
for (auto Range : imageRanges) {
auto Start = std::get<0>(Range);
auto End = std::get<1>(Range);
if (Start.getAddressData() <= Address.getAddressData()
&& Address.getAddressData() < End.getAddressData())
return true;
}
return false;
}
/// Return a description of the layout of a class instance with the given
/// metadata as its isa pointer.
const TypeInfo *getMetadataTypeInfo(StoredPointer MetadataAddress) {
// See if we cached the layout already
auto found = Cache.find(MetadataAddress);
if (found != Cache.end())
return found->second;
auto &TC = getBuilder().getTypeConverter();
const TypeInfo *TI = nullptr;
auto TR = readTypeFromMetadata(MetadataAddress);
auto kind = this->readKindFromMetadata(MetadataAddress);
if (TR != nullptr && kind) {
switch (*kind) {
case MetadataKind::Class: {
// Figure out where the stored properties of this class begin
// by looking at the size of the superclass
auto start =
this->readInstanceStartAndAlignmentFromClassMetadata(MetadataAddress);
// Perform layout
if (start)
TI = TC.getClassInstanceTypeInfo(TR, *start);
break;
}
default:
break;
}
}
// Cache the result for future lookups
Cache[MetadataAddress] = TI;
return TI;
}
/// Return a description of the layout of a class instance with the given
/// metadata as its isa pointer.
const TypeInfo *getInstanceTypeInfo(StoredPointer ObjectAddress) {
auto MetadataAddress = readMetadataFromInstance(ObjectAddress);
if (!MetadataAddress)
return nullptr;
auto kind = this->readKindFromMetadata(*MetadataAddress);
if (!kind)
return nullptr;
switch (*kind) {
case MetadataKind::Class:
return getMetadataTypeInfo(*MetadataAddress);
case MetadataKind::HeapLocalVariable: {
auto CDAddr = this->readCaptureDescriptorFromMetadata(*MetadataAddress);
if (!CDAddr)
return nullptr;
if (!CDAddr->isResolved())
return nullptr;
// FIXME: Non-generic SIL boxes also use the HeapLocalVariable metadata
// kind, but with a null capture descriptor right now (see
// FixedBoxTypeInfoBase::allocate).
//
// Non-generic SIL boxes share metadata among types with compatible
// layout, but we need some way to get an outgoing pointer map for them.
auto CD = getBuilder().getCaptureDescriptor(
CDAddr->getResolvedAddress().getAddressData());
if (CD == nullptr)
return nullptr;
auto Info = getBuilder().getClosureContextInfo(CD);
return getClosureContextInfo(ObjectAddress, Info);
}
case MetadataKind::HeapGenericLocalVariable: {
// Generic SIL @box type - there is always an instantiated metadata
// pointer for the boxed type.
if (auto Meta = readMetadata(*MetadataAddress)) {
auto GenericHeapMeta =
cast<TargetGenericBoxHeapMetadata<Runtime>>(Meta.getLocalBuffer());
return getMetadataTypeInfo(GenericHeapMeta->BoxedType);
}
return nullptr;
}
case MetadataKind::ErrorObject:
// Error boxed existential on non-Objective-C runtime target
return nullptr;
default:
return nullptr;
}
}
bool
projectExistential(RemoteAddress ExistentialAddress,
const TypeRef *ExistentialTR,
const TypeRef **OutInstanceTR,
RemoteAddress *OutInstanceAddress) {
if (ExistentialTR == nullptr)
return false;
auto ExistentialTI = getTypeInfo(ExistentialTR);
if (ExistentialTI == nullptr)
return false;
auto ExistentialRecordTI = dyn_cast<const RecordTypeInfo>(ExistentialTI);
if (ExistentialRecordTI == nullptr)
return false;
switch (ExistentialRecordTI->getRecordKind()) {
// Class existentials have trivial layout.
// It is itself the pointer to the instance followed by the witness tables.
case RecordKind::ClassExistential:
// This is just AnyObject.
*OutInstanceTR = ExistentialRecordTI->getFields()[0].TR;
*OutInstanceAddress = ExistentialAddress;
return true;
case RecordKind::OpaqueExistential: {
auto OptMetaAndValue =
readMetadataAndValueOpaqueExistential(ExistentialAddress);
if (!OptMetaAndValue)
return false;
auto InstanceTR = readTypeFromMetadata(
OptMetaAndValue->MetadataAddress.getAddressData());
if (!InstanceTR)
return false;
*OutInstanceTR = InstanceTR;
*OutInstanceAddress = OptMetaAndValue->PayloadAddress;
return true;
}
case RecordKind::ErrorExistential: {
auto OptMetaAndValue =
readMetadataAndValueErrorExistential(ExistentialAddress);
if (!OptMetaAndValue)
return false;
// FIXME: Check third value, 'IsBridgedError'
auto InstanceTR = readTypeFromMetadata(
OptMetaAndValue->MetadataAddress.getAddressData());
if (!InstanceTR)
return false;
*OutInstanceTR = InstanceTR;
*OutInstanceAddress = OptMetaAndValue->PayloadAddress;
return true;
}
default:
return false;
}
}
/// Projects the value of an enum.
///
/// Takes the address and typeref for an enum and determines the
/// index of the currently-selected case within the enum.
/// You can use this index with `swift_reflection_childOfTypeRef`
/// to get detailed information about the specific case.
///
/// Returns true if the enum case could be successfully determined. In
/// particular, note that this code may return false for valid in-memory data
/// if the compiler used a strategy we do not yet understand.
bool projectEnumValue(RemoteAddress EnumAddress,
const TypeRef *EnumTR,
int *CaseIndex) {
// Get the TypeInfo and sanity-check it
if (EnumTR == nullptr) {
return false;
}
auto TI = getTypeInfo(EnumTR);
if (TI == nullptr) {
return false;
}
auto EnumTI = dyn_cast<const EnumTypeInfo>(TI);
if (EnumTI == nullptr){
return false;
}
return EnumTI->projectEnumValue(getReader(), EnumAddress, CaseIndex);
}
/// Return a description of the layout of a value with the given type.
const TypeInfo *getTypeInfo(const TypeRef *TR) {
if (TR == nullptr) {
return nullptr;
} else {
return getBuilder().getTypeConverter().getTypeInfo(TR);
}
}
private:
const TypeInfo *getClosureContextInfo(StoredPointer Context,
const ClosureContextInfo &Info) {
RecordTypeInfoBuilder Builder(getBuilder().getTypeConverter(),
RecordKind::ClosureContext);
auto Metadata = readMetadataFromInstance(Context);
if (!Metadata)
return nullptr;
// Calculate the offset of the first capture.
// See GenHeap.cpp, buildPrivateMetadata().
auto OffsetToFirstCapture =
this->readOffsetToFirstCaptureFromMetadata(*Metadata);
if (!OffsetToFirstCapture)
return nullptr;
// Initialize the builder.
Builder.addField(*OffsetToFirstCapture,
/*alignment=*/sizeof(StoredPointer),
/*numExtraInhabitants=*/0,
/*bitwiseTakable=*/true);
// Skip the closure's necessary bindings struct, if it's present.
auto SizeOfNecessaryBindings = Info.NumBindings * sizeof(StoredPointer);
Builder.addField(/*size=*/SizeOfNecessaryBindings,
/*alignment=*/sizeof(StoredPointer),
/*numExtraInhabitants=*/0,
/*bitwiseTakable=*/true);
// FIXME: should be unordered_set but I'm too lazy to write a hash
// functor
std::set<std::pair<const TypeRef *, const MetadataSource *>> Done;
GenericArgumentMap Subs;
ArrayRef<const TypeRef *> CaptureTypes = Info.CaptureTypes;
// Closure context element layout depends on the layout of the
// captured types, but captured types might depend on element
// layout (of previous elements). Use an iterative approach to
// solve the problem.
while (!CaptureTypes.empty()) {
const TypeRef *OrigCaptureTR = CaptureTypes[0];
// If we failed to demangle the capture type, we cannot proceed.
if (OrigCaptureTR == nullptr)
return nullptr;
const TypeRef *SubstCaptureTR = nullptr;
// If we have enough substitutions to make this captured value's
// type concrete, or we know it's size anyway (because it is a
// class reference or metatype, for example), go ahead and add
// it to the layout.
if (OrigCaptureTR->isConcreteAfterSubstitutions(Subs))
SubstCaptureTR = OrigCaptureTR->subst(getBuilder(), Subs);
else if (getBuilder().getTypeConverter().hasFixedSize(OrigCaptureTR))
SubstCaptureTR = OrigCaptureTR;
if (SubstCaptureTR != nullptr) {
Builder.addField("", SubstCaptureTR);
if (Builder.isInvalid())
return nullptr;
// Try the next capture type.
CaptureTypes = CaptureTypes.slice(1);
continue;
}
// Ok, we do not have enough substitutions yet. Perhaps we have
// enough elements figured out that we can pick off some
// metadata sources though, and use those to derive some new
// substitutions.
bool Progress = false;
for (auto Source : Info.MetadataSources) {
// Don't read a source more than once.
if (Done.count(Source))
continue;
// If we don't have enough information to read this source
// (because it is fulfilled by metadata from a capture at
// at unknown offset), keep going.
if (!isMetadataSourceReady(Source.second, Builder))
continue;
auto Metadata = readMetadataSource(Context, Source.second, Builder);
if (!Metadata)
return nullptr;
auto *SubstTR = readTypeFromMetadata(*Metadata);
if (SubstTR == nullptr)
return nullptr;
if (!TypeRef::deriveSubstitutions(Subs, Source.first, SubstTR))
return nullptr;
Done.insert(Source);
Progress = true;
}
// If we failed to make any forward progress above, we're stuck
// and cannot close out this layout.
if (!Progress)
return nullptr;
}
// Ok, we have a complete picture now.
return Builder.build();
}
/// Checks if we have enough information to read the given metadata
/// source.
///
/// \param Builder Used to obtain offsets of elements known so far.
bool isMetadataSourceReady(const MetadataSource *MS,
const RecordTypeInfoBuilder &Builder) {
switch (MS->getKind()) {
case MetadataSourceKind::ClosureBinding:
return true;
case MetadataSourceKind::ReferenceCapture: {
unsigned Index = cast<ReferenceCaptureMetadataSource>(MS)->getIndex();
return Index < Builder.getNumFields();
}
case MetadataSourceKind::MetadataCapture: {
unsigned Index = cast<MetadataCaptureMetadataSource>(MS)->getIndex();
return Index < Builder.getNumFields();
}
case MetadataSourceKind::GenericArgument: {
auto Base = cast<GenericArgumentMetadataSource>(MS)->getSource();
return isMetadataSourceReady(Base, Builder);
}
case MetadataSourceKind::Self:
case MetadataSourceKind::SelfWitnessTable:
return true;
}
swift_runtime_unreachable("Unhandled MetadataSourceKind in switch.");
}
/// Read metadata for a captured generic type from a closure context.
///
/// \param Context The closure context in the remote process.
///
/// \param MS The metadata source, which must be "ready" as per the
/// above.
///
/// \param Builder Used to obtain offsets of elements known so far.
llvm::Optional<StoredPointer>
readMetadataSource(StoredPointer Context,
const MetadataSource *MS,
const RecordTypeInfoBuilder &Builder) {
switch (MS->getKind()) {
case MetadataSourceKind::ClosureBinding: {
unsigned Index = cast<ClosureBindingMetadataSource>(MS)->getIndex();
// Skip the context's HeapObject header
// (one word each for isa pointer and reference counts).
//
// Metadata and conformance tables are stored consecutively after
// the heap object header, in the 'necessary bindings' area.
//
// We should only have the index of a type metadata record here.
unsigned Offset = getSizeOfHeapObject() +
sizeof(StoredPointer) * Index;
StoredPointer MetadataAddress;
if (!getReader().readInteger(RemoteAddress(Context + Offset),
&MetadataAddress))
break;
return MetadataAddress;
}
case MetadataSourceKind::ReferenceCapture: {
unsigned Index = cast<ReferenceCaptureMetadataSource>(MS)->getIndex();
// We should already have enough type information to know the offset
// of this capture in the context.
unsigned CaptureOffset = Builder.getFieldOffset(Index);
StoredPointer CaptureAddress;
if (!getReader().readInteger(RemoteAddress(Context + CaptureOffset),
&CaptureAddress))
break;
// Read the requested capture's isa pointer.
return readMetadataFromInstance(CaptureAddress);
}
case MetadataSourceKind::MetadataCapture: {
unsigned Index = cast<MetadataCaptureMetadataSource>(MS)->getIndex();
// We should already have enough type information to know the offset
// of this capture in the context.
unsigned CaptureOffset = Builder.getFieldOffset(Index);
StoredPointer CaptureAddress;
if (!getReader().readInteger(RemoteAddress(Context + CaptureOffset),
&CaptureAddress))
break;
return CaptureAddress;
}
case MetadataSourceKind::GenericArgument: {
auto *GAMS = cast<GenericArgumentMetadataSource>(MS);
auto Base = readMetadataSource(Context, GAMS->getSource(), Builder);
if (!Base)
break;
unsigned Index = GAMS->getIndex();
auto Arg = readGenericArgFromMetadata(*Base, Index);
if (!Arg)
break;
return *Arg;
}
case MetadataSourceKind::Self:
case MetadataSourceKind::SelfWitnessTable:
break;
}
return llvm::None;
}
};
} // end namespace reflection
} // end namespace swift
#endif // SWIFT_REFLECTION_REFLECTIONCONTEXT_H
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