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[NFC][lldb] Clean up LLDBMemoryReader changes. #11030

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merged 1 commit into from
Jul 24, 2025
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[NFC][lldb] Clean up LLDBMemoryReader changes. #11030

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65 changes: 37 additions & 28 deletions lldb/source/Plugins/LanguageRuntime/Swift/LLDBMemoryReader.cpp
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -315,11 +315,11 @@ LLDBMemoryReader::resolvePointer(swift::remote::RemoteAddress address,

bool LLDBMemoryReader::readBytes(swift::remote::RemoteAddress address,
uint8_t *dest, uint64_t size) {
auto [success, _] = readBytesImpl(address, dest, size);
return success;
auto read_bytes_result = readBytesImpl(address, dest, size);
return read_bytes_result != ReadBytesResult::fail;
}

std::pair<bool, bool>
LLDBMemoryReader::ReadBytesResult
LLDBMemoryReader::readBytesImpl(swift::remote::RemoteAddress address,
uint8_t *dest, uint64_t size) {
Log *log = GetLog(LLDBLog::Types);
Expand All @@ -330,15 +330,15 @@ LLDBMemoryReader::readBytesImpl(swift::remote::RemoteAddress address,
if (overflow) {
LLDB_LOGV(log, "[MemoryReader] address {0:x} + size {1} overflows", addr,
size);
return {false, false};
return ReadBytesResult::fail;
}
if (addr >= *m_local_buffer &&
end <= *m_local_buffer + m_local_buffer_size) {
// If this crashes, the assumptions stated in
// GetDynamicTypeAndAddress_Protocol() most likely no longer
// hold.
memcpy(dest, (void *)addr, size);
return {true, false};
return ReadBytesResult::success_from_file;
}
}

Expand All @@ -353,7 +353,7 @@ LLDBMemoryReader::readBytesImpl(swift::remote::RemoteAddress address,
if (!maybeAddr) {
LLDB_LOGV(log, "[MemoryReader] could not resolve address {0:x}",
address.getRawAddress());
return {false, false};
return ReadBytesResult::fail;
}
auto addr = *maybeAddr;
if (addr.IsSectionOffset()) {
Expand All @@ -362,15 +362,16 @@ LLDBMemoryReader::readBytesImpl(swift::remote::RemoteAddress address,
if (object_file->GetType() == ObjectFile::Type::eTypeDebugInfo) {
LLDB_LOGV(log, "[MemoryReader] Reading memory from symbol rich binary");

bool success = object_file->ReadSectionData(section.get(),
addr.GetOffset(), dest, size);
return {success, false};
if (object_file->ReadSectionData(section.get(), addr.GetOffset(), dest,
size))
return ReadBytesResult::success_from_file;
return ReadBytesResult::fail;
}
}

if (size > m_max_read_amount) {
LLDB_LOGV(log, "[MemoryReader] memory read exceeds maximum allowed size");
return {false, false};
return ReadBytesResult::fail;
}
Target &target(m_process.GetTarget());
Status error;
Expand All @@ -384,12 +385,12 @@ LLDBMemoryReader::readBytesImpl(swift::remote::RemoteAddress address,
&did_read_live_memory)) {
LLDB_LOGV(log,
"[MemoryReader] memory read returned fewer bytes than asked for");
return {false, did_read_live_memory};
return ReadBytesResult::fail;
}
if (error.Fail()) {
LLDB_LOGV(log, "[MemoryReader] memory read returned error: {0}",
error.AsCString());
return {false, did_read_live_memory};
return ReadBytesResult::fail;
}

auto format_data = [](auto dest, auto size) {
Expand All @@ -403,7 +404,8 @@ LLDBMemoryReader::readBytesImpl(swift::remote::RemoteAddress address,
LLDB_LOGV(log, "[MemoryReader] memory read returned data: {0}",
format_data(dest, size));

return {true, did_read_live_memory};
return did_read_live_memory ? ReadBytesResult::success_from_memory
: ReadBytesResult::success_from_file;
}

bool LLDBMemoryReader::readString(swift::remote::RemoteAddress address,
Expand Down Expand Up @@ -613,24 +615,31 @@ bool LLDBMemoryReader::readRemoteAddressImpl(
std::size_t size) {
assert((size == 4 || size == 8) &&
"Only 32 or 64 bit architectures are supported!");
auto *dest = (uint8_t *)std::malloc(size);
auto defer = llvm::make_scope_exit([&] { free(dest); });

auto [success, did_read_live_memory] = readBytesImpl(address, dest, size);
if (!success)
if (size != 4 && size != 8)
return false;

uint8_t addressSpace = did_read_live_memory
? swift::remote::RemoteAddress::DefaultAddressSpace
: LLDBAddressSpace;
if (size == 4)
out = swift::remote::RemoteAddress(*reinterpret_cast<uint32_t *>(dest),
addressSpace);
else if (size == 8)
out = swift::remote::RemoteAddress(*reinterpret_cast<uint64_t *>(dest),
addressSpace);
else
uint64_t buf;
auto read_bytes_result =
readBytesImpl(address, reinterpret_cast<uint8_t *>(&buf), size);

uint8_t addressSpace;
switch (read_bytes_result) {
case ReadBytesResult::success_from_file:
addressSpace = LLDBAddressSpace;
break;
case ReadBytesResult::success_from_memory:
addressSpace = swift::remote::RemoteAddress::DefaultAddressSpace;
break;
case ReadBytesResult::fail:
return false;
}
ByteOrder byte_order = m_process.GetTarget().GetArchitecture().GetByteOrder();
uint32_t byte_size =
m_process.GetTarget().GetArchitecture().GetAddressByteSize();
DataExtractor extractor((const void *)&buf, size, byte_order, byte_size);
lldb::offset_t offset = 0;
auto data = extractor.GetMaxU64(&offset, size);
out = swift::remote::RemoteAddress(data, addressSpace);
return true;
}

Expand Down
8 changes: 6 additions & 2 deletions lldb/source/Plugins/LanguageRuntime/Swift/LLDBMemoryReader.h
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -51,6 +51,9 @@ class MemoryReaderLocalBufferHolder {

class LLDBMemoryReader : public swift::remote::MemoryReader {
public:
/// Besides address space 0 (the DefaultAddressSpace), subclasses are free to
/// use any address space for their own implementation purposes. LLDB uses
/// this address space to track file addresses it sends to RemoteInspection.
static constexpr uint8_t LLDBAddressSpace = 1;

LLDBMemoryReader(Process &p,
Expand Down Expand Up @@ -124,11 +127,12 @@ class LLDBMemoryReader : public swift::remote::MemoryReader {
std::optional<Address>
remoteAddressToLLDBAddress(swift::remote::RemoteAddress address) const;

enum class ReadBytesResult { fail, success_from_file, success_from_memory };
/// Implementation detail of readBytes. Returns a pair where the first element
/// indicates whether the memory was read successfully, the second element
/// indicates whether live memory was read.
std::pair<bool, bool> readBytesImpl(swift::remote::RemoteAddress address,
uint8_t *dest, uint64_t size);
ReadBytesResult readBytesImpl(swift::remote::RemoteAddress address,
uint8_t *dest, uint64_t size);

/// Reads memory from the symbol rich binary from the address into dest.
/// \return true if it was able to successfully read memory.
Expand Down