gipddecode
Decode Google IP Discovery data
SYNOPSIS
gipddecode [OPTIONS] [-i TRACE_FILE] [-o OUTPUT_FILE] [BINARY_PATH]
PARAMETERS
-h, --help
Displays a brief help message and exits.
-v, --version
Prints the version information of the utility and exits.
-i FILE, --input FILE
Specifies the input file containing the raw Intel Processor Trace (IPT) data to be decoded. This can be a raw trace stream or a file generated by tools like perf.
-o FILE, --output FILE
Specifies the output file where the decoded instruction stream will be written. If not specified, output is typically sent to standard output (stdout).
-p PATH, --path PATH
Adds a directory to the search path for executables and shared libraries. This is crucial for gipddecode to resolve instruction addresses to meaningful symbolic names (function names, variable names).
-s CPU_ID, --cpu CPU_ID
Specifies the CPU ID for which the trace data should be decoded. Useful when the input trace file contains data from multiple CPUs.
-d, --debug
Enables verbose debug output during the decoding process, providing more detailed information about the trace parsing.
-l LEVEL, --log-level LEVEL
Sets the verbosity level of the output. Higher levels provide more detailed information about the decoded trace.
-x, --no-ip-filtering
Disables filtering of non-instruction pointer trace packets, displaying all raw trace events.
-c, --cycle-accurate
Attempts to perform cycle-accurate decoding, providing timestamps for each instruction if supported by the trace data and hardware.
DESCRIPTION
The gipddecode command is a specialized utility designed to decode raw Intel Processor Trace (IPT) data streams into human-readable instruction sequences. Intel Processor Trace is a CPU feature, introduced with Broadwell processors, that records program execution flow with minimal overhead, capturing branches, changes in instruction pointer, and other events. This raw trace data, often captured by tools like perf on Linux, is highly compressed and not directly readable.
gipddecode processes this binary trace data, reconstructs the execution path, and displays the sequence of executed instructions, often including symbolic information if the corresponding executables and libraries are available. It is an invaluable tool for low-level debugging, reverse engineering, performance analysis (understanding hot paths, branch mispredictions), and security research, allowing developers and analysts to precisely observe the CPU's execution flow. Due to its specialized nature, gipddecode is typically part of Intel's developer tools, SDKs, or built from libraries like libipt, rather than being a standard command in typical Linux distributions.
CAVEATS
gipddecode is not a standard, universally available Linux command. It typically needs to be installed as part of Intel's development toolchains (e.g., VTune Amplifier, Intel SDKs) or built from source (e.g., from the libipt project).
It requires a CPU with Intel Processor Trace (IPT) capabilities to generate the input trace data.
Effective use often depends on having the exact binaries and libraries that were executing during the trace capture, for proper symbol resolution. Without them, the output will only show raw addresses.
INTEL PROCESSOR TRACE (IPT)
Intel Processor Trace is a hardware feature that records control-flow changes (branches, calls, returns, interrupts, etc.) and other events in a highly compressed binary format. It's used for detailed execution flow analysis without significantly impacting performance. gipddecode is one of the key tools for turning this raw, binary trace data into a human-readable stream of executed instructions.
USAGE WITH <I>PERF</I>
While gipddecode is a standalone utility, its input trace data is often captured using the Linux perf tool. A common workflow involves recording trace data with perf record -e intel_pt//
HISTORY
The advent of Intel Processor Trace (IPT) technology, first introduced with Intel's Broadwell microarchitecture, enabled fine-grained, low-overhead instruction tracing at the hardware level. This capability created a need for specialized software tools to decode the highly compressed binary trace data generated by the CPU.
Utilities like gipddecode emerged to fill this role, often built upon underlying libraries such as libipt (the Intel Processor Trace Decoder Library), which provides the core decoding logic. Its development paralleled the integration of IPT support into debugging and profiling tools like perf on Linux and Intel's proprietary VTune Amplifier, becoming an essential component for detailed execution analysis on Intel platforms.