forked from OSchip/llvm-project
71 lines
2.6 KiB
C++
71 lines
2.6 KiB
C++
//===- FileHeaderReader.cpp - XRay File Header Reader --------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
#include "llvm/XRay/FileHeaderReader.h"
|
|
|
|
namespace llvm {
|
|
namespace xray {
|
|
|
|
// Populates the FileHeader reference by reading the first 32 bytes of the file.
|
|
Expected<XRayFileHeader> readBinaryFormatHeader(DataExtractor &HeaderExtractor,
|
|
uint32_t &OffsetPtr) {
|
|
// FIXME: Maybe deduce whether the data is little or big-endian using some
|
|
// magic bytes in the beginning of the file?
|
|
|
|
// First 32 bytes of the file will always be the header. We assume a certain
|
|
// format here:
|
|
//
|
|
// (2) uint16 : version
|
|
// (2) uint16 : type
|
|
// (4) uint32 : bitfield
|
|
// (8) uint64 : cycle frequency
|
|
// (16) - : padding
|
|
XRayFileHeader FileHeader;
|
|
auto PreReadOffset = OffsetPtr;
|
|
FileHeader.Version = HeaderExtractor.getU16(&OffsetPtr);
|
|
if (OffsetPtr == PreReadOffset)
|
|
return createStringError(
|
|
std::make_error_code(std::errc::invalid_argument),
|
|
"Failed reading version from file header at offset %d.", OffsetPtr);
|
|
|
|
PreReadOffset = OffsetPtr;
|
|
FileHeader.Type = HeaderExtractor.getU16(&OffsetPtr);
|
|
if (OffsetPtr == PreReadOffset)
|
|
return createStringError(
|
|
std::make_error_code(std::errc::invalid_argument),
|
|
"Failed reading file type from file header at offset %d.", OffsetPtr);
|
|
|
|
PreReadOffset = OffsetPtr;
|
|
uint32_t Bitfield = HeaderExtractor.getU32(&OffsetPtr);
|
|
if (OffsetPtr == PreReadOffset)
|
|
return createStringError(
|
|
std::make_error_code(std::errc::invalid_argument),
|
|
"Failed reading flag bits from file header at offset %d.", OffsetPtr);
|
|
|
|
FileHeader.ConstantTSC = Bitfield & 1uL;
|
|
FileHeader.NonstopTSC = Bitfield & 1uL << 1;
|
|
PreReadOffset = OffsetPtr;
|
|
FileHeader.CycleFrequency = HeaderExtractor.getU64(&OffsetPtr);
|
|
if (OffsetPtr == PreReadOffset)
|
|
return createStringError(
|
|
std::make_error_code(std::errc::invalid_argument),
|
|
"Failed reading cycle frequency from file header at offset %d.",
|
|
OffsetPtr);
|
|
|
|
std::memcpy(&FileHeader.FreeFormData,
|
|
HeaderExtractor.getData().bytes_begin() + OffsetPtr, 16);
|
|
|
|
// Manually advance the offset pointer 16 bytes, after getting a raw memcpy
|
|
// from the underlying data.
|
|
OffsetPtr += 16;
|
|
return std::move(FileHeader);
|
|
}
|
|
|
|
} // namespace xray
|
|
} // namespace llvm
|