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Diffstat (limited to 'lib/XRay/BlockVerifier.cpp')
| -rw-r--r-- | lib/XRay/BlockVerifier.cpp | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/lib/XRay/BlockVerifier.cpp b/lib/XRay/BlockVerifier.cpp new file mode 100644 index 000000000000..5e949ec4e46a --- /dev/null +++ b/lib/XRay/BlockVerifier.cpp @@ -0,0 +1,205 @@ +//===- BlockVerifier.cpp - FDR Block Verifier -----------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +#include "llvm/XRay/BlockVerifier.h" +#include "llvm/Support/Error.h" + +namespace llvm { +namespace xray { +namespace { + +constexpr unsigned long long mask(BlockVerifier::State S) { + return 1uLL << static_cast<std::size_t>(S); +} + +constexpr std::size_t number(BlockVerifier::State S) { + return static_cast<std::size_t>(S); +} + +StringRef recordToString(BlockVerifier::State R) { + switch (R) { + case BlockVerifier::State::BufferExtents: + return "BufferExtents"; + case BlockVerifier::State::NewBuffer: + return "NewBuffer"; + case BlockVerifier::State::WallClockTime: + return "WallClockTime"; + case BlockVerifier::State::PIDEntry: + return "PIDEntry"; + case BlockVerifier::State::NewCPUId: + return "NewCPUId"; + case BlockVerifier::State::TSCWrap: + return "TSCWrap"; + case BlockVerifier::State::CustomEvent: + return "CustomEvent"; + case BlockVerifier::State::Function: + return "Function"; + case BlockVerifier::State::CallArg: + return "CallArg"; + case BlockVerifier::State::EndOfBuffer: + return "EndOfBuffer"; + case BlockVerifier::State::TypedEvent: + return "TypedEvent"; + case BlockVerifier::State::StateMax: + case BlockVerifier::State::Unknown: + return "Unknown"; + } + llvm_unreachable("Unkown state!"); +} + +struct Transition { + BlockVerifier::State From; + std::bitset<number(BlockVerifier::State::StateMax)> ToStates; +}; + +} // namespace + +Error BlockVerifier::transition(State To) { + using ToSet = std::bitset<number(State::StateMax)>; + static constexpr std::array<const Transition, number(State::StateMax)> + TransitionTable{{{State::Unknown, + {mask(State::BufferExtents) | mask(State::NewBuffer)}}, + + {State::BufferExtents, {mask(State::NewBuffer)}}, + + {State::NewBuffer, {mask(State::WallClockTime)}}, + + {State::WallClockTime, + {mask(State::PIDEntry) | mask(State::NewCPUId)}}, + + {State::PIDEntry, {mask(State::NewCPUId)}}, + + {State::NewCPUId, + {mask(State::NewCPUId) | mask(State::TSCWrap) | + mask(State::CustomEvent) | mask(State::Function) | + mask(State::EndOfBuffer) | mask(State::TypedEvent)}}, + + {State::TSCWrap, + {mask(State::TSCWrap) | mask(State::NewCPUId) | + mask(State::CustomEvent) | mask(State::Function) | + mask(State::EndOfBuffer) | mask(State::TypedEvent)}}, + + {State::CustomEvent, + {mask(State::CustomEvent) | mask(State::TSCWrap) | + mask(State::NewCPUId) | mask(State::Function) | + mask(State::EndOfBuffer) | mask(State::TypedEvent)}}, + + {State::TypedEvent, + {mask(State::TypedEvent) | mask(State::TSCWrap) | + mask(State::NewCPUId) | mask(State::Function) | + mask(State::EndOfBuffer) | mask(State::CustomEvent)}}, + + {State::Function, + {mask(State::Function) | mask(State::TSCWrap) | + mask(State::NewCPUId) | mask(State::CustomEvent) | + mask(State::CallArg) | mask(State::EndOfBuffer) | + mask(State::TypedEvent)}}, + + {State::CallArg, + {mask(State::CallArg) | mask(State::Function) | + mask(State::TSCWrap) | mask(State::NewCPUId) | + mask(State::CustomEvent) | mask(State::EndOfBuffer) | + mask(State::TypedEvent)}}, + + {State::EndOfBuffer, {}}}}; + + if (CurrentRecord >= State::StateMax) + return createStringError( + std::make_error_code(std::errc::executable_format_error), + "BUG (BlockVerifier): Cannot find transition table entry for %s, " + "transitioning to %s.", + recordToString(CurrentRecord).data(), recordToString(To).data()); + + // If we're at an EndOfBuffer record, we ignore anything that follows that + // isn't a NewBuffer record. + if (CurrentRecord == State::EndOfBuffer && To != State::NewBuffer) + return Error::success(); + + auto &Mapping = TransitionTable[number(CurrentRecord)]; + auto &Destinations = Mapping.ToStates; + assert(Mapping.From == CurrentRecord && + "BUG: Wrong index for record mapping."); + if ((Destinations & ToSet(mask(To))) == 0) + return createStringError( + std::make_error_code(std::errc::executable_format_error), + "BlockVerifier: Invalid transition from %s to %s.", + recordToString(CurrentRecord).data(), recordToString(To).data()); + + CurrentRecord = To; + return Error::success(); +} // namespace xray + +Error BlockVerifier::visit(BufferExtents &) { + return transition(State::BufferExtents); +} + +Error BlockVerifier::visit(WallclockRecord &) { + return transition(State::WallClockTime); +} + +Error BlockVerifier::visit(NewCPUIDRecord &) { + return transition(State::NewCPUId); +} + +Error BlockVerifier::visit(TSCWrapRecord &) { + return transition(State::TSCWrap); +} + +Error BlockVerifier::visit(CustomEventRecord &) { + return transition(State::CustomEvent); +} + +Error BlockVerifier::visit(CustomEventRecordV5 &) { + return transition(State::CustomEvent); +} + +Error BlockVerifier::visit(TypedEventRecord &) { + return transition(State::TypedEvent); +} + +Error BlockVerifier::visit(CallArgRecord &) { + return transition(State::CallArg); +} + +Error BlockVerifier::visit(PIDRecord &) { return transition(State::PIDEntry); } + +Error BlockVerifier::visit(NewBufferRecord &) { + return transition(State::NewBuffer); +} + +Error BlockVerifier::visit(EndBufferRecord &) { + return transition(State::EndOfBuffer); +} + +Error BlockVerifier::visit(FunctionRecord &) { + return transition(State::Function); +} + +Error BlockVerifier::verify() { + // The known terminal conditions are the following: + switch (CurrentRecord) { + case State::EndOfBuffer: + case State::NewCPUId: + case State::CustomEvent: + case State::TypedEvent: + case State::Function: + case State::CallArg: + case State::TSCWrap: + return Error::success(); + default: + return createStringError( + std::make_error_code(std::errc::executable_format_error), + "BlockVerifier: Invalid terminal condition %s, malformed block.", + recordToString(CurrentRecord).data()); + } +} + +void BlockVerifier::reset() { CurrentRecord = State::Unknown; } + +} // namespace xray +} // namespace llvm |