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[Reflection] Try to read only the reflection sections. #21255

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Merged
merged 3 commits into from
Dec 14, 2018
Merged

[Reflection] Try to read only the reflection sections. #21255

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5b3e97d
[Reflection] Try to read only the reflection sections.
Dec 10, 2018
177293d
[ReflectionContext] Take slide in account.
Dec 11, 2018
04cbdfa
[ReflectionContext] Save buffers and set the correct addresses.
Dec 11, 2018
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66 changes: 51 additions & 15 deletions include/swift/Reflection/ReflectionContext.h
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Original file line number Diff line number Diff line change
Expand Up @@ -139,26 +139,60 @@ class ReflectionContext
if (!Command)
return false;

// Read everything including the __TEXT segment.
Buf = this->getReader().readBytes(ImageStart, Command->vmsize);
auto Start = reinterpret_cast<const char *>(Buf.get());
// 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));
}

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<std::pair<const char *, const char *>, uint32_t> {
auto cmdOffset = Start + Offset + sizeof(typename T::Header);
auto SegCmd = reinterpret_cast<typename T::SegmentCmd *>(cmdOffset);
auto SectAddress = reinterpret_cast<const char *>(cmdOffset) +
sizeof(typename T::SegmentCmd);
for (unsigned I = 0; I < SegCmd->nsects; ++I) {
for (unsigned I = 0; I < NumSect; ++I) {
auto S = reinterpret_cast<typename T::Section *>(
SectAddress + (I * sizeof(typename T::Section)));
SectionsBuf + (I * sizeof(typename T::Section)));
if (strncmp(S->sectname, Name.c_str(), strlen(Name.c_str())) != 0)
continue;
auto Slide = ImageStart.getAddressData() - Command->vmaddr;
auto RemoteSecStart = S->addr + Slide;
auto LocalSecStart = RemoteSecStart - ImageStart.getAddressData() + Start;
auto SecSize = S->size;
return {{LocalSecStart, LocalSecStart + SecSize}, 0};
auto SectBufData = reinterpret_cast<const char *>(SectBuf.get());
auto LocalSectStart =
reinterpret_cast<const char *>(SectBufData + RemoteSecStart - RangeStart);
auto LocalSectEnd = reinterpret_cast<const char *>(LocalSectStart + S->size);
return {{LocalSectStart, LocalSectEnd}, 0};
}
return {{nullptr, nullptr}, 0};
};
Expand All @@ -178,8 +212,8 @@ class ReflectionContext
ReflStrMdSec.first.first == nullptr)
return false;

auto LocalStartAddress = reinterpret_cast<uintptr_t>(Buf.get());
auto RemoteStartAddress = static_cast<uintptr_t>(ImageStart.getAddressData());
auto LocalStartAddress = reinterpret_cast<uintptr_t>(SectBuf.get());
auto RemoteStartAddress = static_cast<uintptr_t>(RangeStart);

ReflectionInfo info = {
{{FieldMdSec.first.first, FieldMdSec.first.second}, 0},
Expand Down Expand Up @@ -212,6 +246,8 @@ class ReflectionContext
}

savedBuffers.push_back(std::move(Buf));
savedBuffers.push_back(std::move(SectBuf));
savedBuffers.push_back(std::move(Sections));
return true;
}

Expand Down