[Feature]: Improve TensorLayout descriptor and add string-based TensorShape querying

[zacharyvincze]

Motivation

Aims to represent tensor layouts as strings and simplify shape dimension querying.

Technical Details

• TensorLayouts are now represented internally as strings.
• TensorShape::permute() method added to convert tensor shapes into other layouts.
• Dimension sizes can now be queried using string representations of the dimension. For example: Tensor.shape("N") or TensorShape["W"].
• TensorShape::containsDim()/TensorLayout::containsDim() methods added to check if a dimension is present in a given tensor.

Test Plan

• Ensure current Python/C++ tests continue to pass.
• Write new unit tests to ensure string-based dimension size querying and the new TensorShape::permute() method works as intended.

Test Result

• All tests pass as intended.

Submission Checklist

• Look over the contributing guidelines at https://github.com/ROCm/ROCm/blob/develop/CONTRIBUTING.md#pull-requests.

[Copilot]

Pull request overview

This pull request refactors the TensorLayout system to use string-based representations internally and adds new capabilities for querying tensor shape dimensions by dimension name and permuting tensor shapes between different layouts.

Changes:

• Replaced the TensorLayoutDesc struct-based system with a string-based representation using layoutStringTable
• Added operator[] overload to query tensor shape dimensions by name (e.g., shape["N"])
• Added TensorShape::permute() method to convert tensor shapes between different layouts

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
include/core/tensor_layout.hpp	Removed TensorLayoutDesc struct and replaced descriptor-based methods with string-based implementation; added indexOf(), dimAt(), and string() methods
src/core/tensor_layout.cpp	Implemented new TensorLayout constructor and string-based dimension lookup methods
include/core/tensor_shape.hpp	Added operator[](std::string_view) and permute() method declarations
src/core/tensor_shape.cpp	Implemented string-based dimension indexing and shape permutation logic; improved error messages for index operator
include/core/tensor.hpp	Added shape(std::string_view) method declaration
src/core/tensor.cpp	Implemented shape(std::string_view) method forwarding to TensorShape
tests/roccv/cpp/src/tests/core/tensor/test_tensor_shape.cpp	Added tests for string-based dimension querying and shape permutation

Comments suppressed due to low confidence (1)

include/core/tensor_layout.hpp:27

• Missing #include <string> and #include <string_view> headers. The header file uses std::string in layoutStringTable (line 53), m_layoutString (line 139), and the return type of string() method (line 88), as well as std::string_view in method signatures indexOf() (line 73) and dimAt() (line 81). These headers must be included to ensure the code compiles independently.

#include <unordered_map>

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[codecov-commenter]

Codecov Report

❌ Patch coverage is 72.72727% with 15 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/core/tensor_layout.cpp	56.00%	8 Missing and 3 partials ⚠️
include/core/tensor_layout.hpp	80.00%	2 Missing ⚠️
include/core/tensor_shape.hpp	0.00%	1 Missing ⚠️
src/core/tensor.cpp	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #112      +/-   ##
===========================================
+ Coverage    73.76%   73.78%   +0.02%     
===========================================
  Files           72       74       +2     
  Lines         2828     2864      +36     
  Branches       610      615       +5     
===========================================
+ Hits          2086     2113      +27     
- Misses         325      332       +7     
- Partials       417      419       +2     

Files with missing lines	Coverage Δ
include/core/tensor.hpp	62.50% <ø> (ø)
src/core/tensor_shape.cpp	82.76% <100.00%> (+4.19%)	⬆️
include/core/tensor_shape.hpp	0.00% <0.00%> (ø)
src/core/tensor.cpp	70.37% <0.00%> (-0.66%)	⬇️
include/core/tensor_layout.hpp	83.33% <80.00%> (+13.33%)	⬆️
src/core/tensor_layout.cpp	56.00% <56.00%> (ø)

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