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//===- FDRRecordProducer.cpp - XRay FDR Mode Record Producer --------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "llvm/XRay/FDRRecordProducer.h"
#include "llvm/Support/DataExtractor.h"
#include <cstdint>
namespace llvm {
namespace xray {
namespace {
// Keep this in sync with the values written in the XRay FDR mode runtime in
// compiler-rt.
enum MetadataRecordKinds : uint8_t {
NewBufferKind,
EndOfBufferKind,
NewCPUIdKind,
TSCWrapKind,
WalltimeMarkerKind,
CustomEventMarkerKind,
CallArgumentKind,
BufferExtentsKind,
TypedEventMarkerKind,
PidKind,
// This is an end marker, used to identify the upper bound for this enum.
EnumEndMarker,
};
Expected<std::unique_ptr<Record>>
metadataRecordType(const XRayFileHeader &Header, uint8_t T) {
if (T >= static_cast<uint8_t>(MetadataRecordKinds::EnumEndMarker))
return createStringError(std::make_error_code(std::errc::invalid_argument),
"Invalid metadata record type: %d", T);
switch (T) {
case MetadataRecordKinds::NewBufferKind:
return make_unique<NewBufferRecord>();
case MetadataRecordKinds::EndOfBufferKind:
if (Header.Version >= 2)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"End of buffer records are no longer supported starting version "
"2 of the log.");
return make_unique<EndBufferRecord>();
case MetadataRecordKinds::NewCPUIdKind:
return make_unique<NewCPUIDRecord>();
case MetadataRecordKinds::TSCWrapKind:
return make_unique<TSCWrapRecord>();
case MetadataRecordKinds::WalltimeMarkerKind:
return make_unique<WallclockRecord>();
case MetadataRecordKinds::CustomEventMarkerKind:
if (Header.Version >= 5)
return make_unique<CustomEventRecordV5>();
return make_unique<CustomEventRecord>();
case MetadataRecordKinds::CallArgumentKind:
return make_unique<CallArgRecord>();
case MetadataRecordKinds::BufferExtentsKind:
return make_unique<BufferExtents>();
case MetadataRecordKinds::TypedEventMarkerKind:
return make_unique<TypedEventRecord>();
case MetadataRecordKinds::PidKind:
return make_unique<PIDRecord>();
case MetadataRecordKinds::EnumEndMarker:
llvm_unreachable("Invalid MetadataRecordKind");
}
llvm_unreachable("Unhandled MetadataRecordKinds enum value");
}
constexpr bool isMetadataIntroducer(uint8_t FirstByte) {
return FirstByte & 0x01u;
}
} // namespace
Expected<std::unique_ptr<Record>>
FileBasedRecordProducer::findNextBufferExtent() {
// We seek one byte at a time until we find a suitable buffer extents metadata
// record introducer.
std::unique_ptr<Record> R;
while (!R) {
auto PreReadOffset = OffsetPtr;
uint8_t FirstByte = E.getU8(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading one byte from offset %d.", OffsetPtr);
if (isMetadataIntroducer(FirstByte)) {
auto LoadedType = FirstByte >> 1;
if (LoadedType == MetadataRecordKinds::BufferExtentsKind) {
auto MetadataRecordOrErr = metadataRecordType(Header, LoadedType);
if (!MetadataRecordOrErr)
return MetadataRecordOrErr.takeError();
R = std::move(MetadataRecordOrErr.get());
RecordInitializer RI(E, OffsetPtr);
if (auto Err = R->apply(RI))
return std::move(Err);
return std::move(R);
}
}
}
llvm_unreachable("Must always terminate with either an error or a record.");
}
Expected<std::unique_ptr<Record>> FileBasedRecordProducer::produce() {
// First, we set up our result record.
std::unique_ptr<Record> R;
// Before we do any further reading, we should check whether we're at the end
// of the current buffer we're been consuming. In FDR logs version >= 3, we
// rely on the buffer extents record to determine how many bytes we should be
// considering as valid records.
if (Header.Version >= 3 && CurrentBufferBytes == 0) {
// Find the next buffer extents record.
auto BufferExtentsOrError = findNextBufferExtent();
if (!BufferExtentsOrError)
return joinErrors(
BufferExtentsOrError.takeError(),
createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed to find the next BufferExtents record."));
R = std::move(BufferExtentsOrError.get());
assert(R != nullptr);
assert(isa<BufferExtents>(R.get()));
auto BE = dyn_cast<BufferExtents>(R.get());
CurrentBufferBytes = BE->size();
return std::move(R);
}
//
// At the top level, we read one byte to determine the type of the record to
// create. This byte will comprise of the following bits:
//
// - offset 0: A '1' indicates a metadata record, a '0' indicates a function
// record.
// - offsets 1-7: For metadata records, this will indicate the kind of
// metadata record should be loaded.
//
// We read first byte, then create the appropriate type of record to consume
// the rest of the bytes.
auto PreReadOffset = OffsetPtr;
uint8_t FirstByte = E.getU8(&OffsetPtr);
if (OffsetPtr == PreReadOffset)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Failed reading one byte from offset %d.", OffsetPtr);
// For metadata records, handle especially here.
if (isMetadataIntroducer(FirstByte)) {
auto LoadedType = FirstByte >> 1;
auto MetadataRecordOrErr = metadataRecordType(Header, LoadedType);
if (!MetadataRecordOrErr)
return joinErrors(
MetadataRecordOrErr.takeError(),
createStringError(
std::make_error_code(std::errc::executable_format_error),
"Encountered an unsupported metadata record (%d) at offset %d.",
LoadedType, PreReadOffset));
R = std::move(MetadataRecordOrErr.get());
} else {
R = llvm::make_unique<FunctionRecord>();
}
RecordInitializer RI(E, OffsetPtr);
if (auto Err = R->apply(RI))
return std::move(Err);
// If we encountered a BufferExtents record, we should record the remaining
// bytes for the current buffer, to determine when we should start ignoring
// potentially malformed data and looking for buffer extents records.
if (auto BE = dyn_cast<BufferExtents>(R.get())) {
CurrentBufferBytes = BE->size();
} else if (Header.Version >= 3) {
if (OffsetPtr - PreReadOffset > CurrentBufferBytes)
return createStringError(
std::make_error_code(std::errc::executable_format_error),
"Buffer over-read at offset %d (over-read by %d bytes); Record Type "
"= %s.",
OffsetPtr, (OffsetPtr - PreReadOffset) - CurrentBufferBytes,
Record::kindToString(R->getRecordType()).data());
CurrentBufferBytes -= OffsetPtr - PreReadOffset;
}
assert(R != nullptr);
return std::move(R);
}
} // namespace xray
} // namespace llvm
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