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Implement DLQ_GetPtrAuthMask using info from debugserver. … #4110

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Merged
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Mar 24, 2022
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Implement DLQ_GetPtrAuthMask using info from debugserver. … #4110

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14 changes: 11 additions & 3 deletions lldb/source/Plugins/LanguageRuntime/Swift/LLDBMemoryReader.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -14,9 +14,17 @@ namespace lldb_private {
bool LLDBMemoryReader::queryDataLayout(DataLayoutQueryType type, void *inBuffer,
void *outBuffer) {
switch (type) {
// FIXME: add support for case DLQ_GetPtrAuthMask rdar://70729149
case DLQ_GetPtrAuthMask:
return false;
case DLQ_GetPtrAuthMask: {
assert(m_process.GetCodeAddressMask() == m_process.GetDataAddressMask() &&
"not supported");
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Nit: different code and address masks are not supported?

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Does this code know if the mask returned is used for data or for code addresses? Linux standardized on the code/data masks, but I don't think the distinction is possible in AArch64, I'm not sure what target motivated that choice. I think a sanity check of ensuring that they're the same, if we don't know what this mask might be used for, is correct.

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The swift::reflection::MemoryReader API doesn't distinguish between the two.

lldb::addr_t ptrauth_mask = m_process.GetCodeAddressMask();
if (!ptrauth_mask)
return false;
// The mask returned by the process masks out the non-addressable bits.
uint64_t mask_pattern = ~ptrauth_mask;
memcpy(outBuffer, &mask_pattern, sizeof(uint64_t));
return true;
}
case DLQ_GetObjCReservedLowBits: {
auto *result = static_cast<uint8_t *>(outBuffer);
auto &triple = m_process.GetTarget().GetArchitecture().GetTriple();
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