Locality Aware Memory Assignment and Tiling

This is an open source tool for analyzing the per-variable locality of an application in order to reduce the scope of design space exploration in hardware accelerator design.

Dependencies

LLVM/CLANG - Tested on versions 3.5 and 3.8

Getting Started

To run the tool run 'llvm_parser <LLVM_FILE>'

This will export a '.amap' file in the same directory as the original file. The amap file contains a breakdown of all variable index calculations for each function. Variable accesses are also broken down according to the basic block in which they are accessed. Use this alongside a CFG obtained through the opt flag '-dot-cfg' to determine if basic block segments are in distinct parts of the program execution. Temporal locality is heavily dependent on accesses occurring in the same or adjacent segments. Variable strides are calculated within the scope of basic block. They are also averaged across all basic block segments (only valid if segments are in distinct parts of the program).

Non-numeric Stride Descriptors

RUNTIME DEPENDENT STRIDE - This variable has an index based on a variable passed into the function at runtime.
VECTOR WIDTH - Occurs when a multidimensional array is accessed with a uniform constant as its last index. This stride will depend on the element width of the array.
VARIABLE: MULTIPLE CONTROLLING INDVARS - Multiple induction variables are used to access the variable in the same basic block. Stride will vary depending on how these indvars increment with respect to each other.
VARIABLE: IRREGULAR CONSTANTS - Variable is accessed at statically defined points, but there is no uniform stride between these. The average distance is given, but this variable may not progress in a uniform direction.

Authors

Samuel Rogers - sroger48@uncc.edu

Citing Locality Aware Memory Assignment and Tiling

Please cite Locality Aware Memory Assignment and Tiling in your publications if it helps your research work:

@inproceedings{lamat,
 author = {Rogers, Samuel and Tabkhi, Hamed},
 title = {Locality Aware Memory Assignment and Tiling},
 booktitle = {Proceedings of the 55th Annual Design Automation Conference},
 series = {DAC '18},
 year = {2018},
 isbn = {978-1-4503-5700-5},
 location = {San Francisco, California},
 pages = {130:1--130:6},
 articleno = {130},
 numpages = {6},
 url = {http://doi.acm.org/10.1145/3195970.3196070},
 doi = {10.1145/3195970.3196070},
 acmid = {3196070},
 publisher = {ACM},
 address = {New York, NY, USA},
}

License

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Authors: Samuel Rogers - Transformative Computer Systems Architecture Research (TeCSAR) at UNC Charlotte