Driver and API updates for using sym shapes by shivadbhavsar · Pull Request #4946 · ROCm/AMDMIGraphX

shivadbhavsar · 2026-06-05T22:23:40Z

Motivation

Update the driver flags and C/Python APIs to properly allow symbolic shape inputs.

Technical Details

Exposes symbolic dynamic dimensions (sym::expr) through the driver, C API, and Python API.

Driver: --enable-symbolic flag; dynamic-dim JSON now accepts a "name" key to make a dim symbolic. Fixed a crash in the single-object --dim-param path.
C API: new migraphx_sym_expr type (var/literal/parse, arithmetic ops, to_string); dynamic_dimension(sym_expr) + is_symbolic(); onnx_options setters set_use_symbolic_shapes / set_dim_param.
Python: migraphx.sym submodule (expr, var/lit/parse, operators); dynamic_dimension(expr) + is_symbolic(); use_symbolic_shapes on parse_onnx/parse_onnx_buffer, plus dim_params on the buffer variant.
Tests: test/api/test_symbolic_shape.cpp and test/py/test_symbolic_shape.py.

Changelog Category

Add a CHANGELOG.md entry for any option other than Not Applicable

- Added: New functionality.
- Changed: Changes to existing functionality.
- Removed: Functionality or support that has been removed. (Compared to a previous release)
- Optimized: Component performance that has been optimized or improved.
- Resolved Issues: Known issues from a previous version that have been resolved.
- Not Applicable: This PR is not to be included in the changelog.

Copilot

Pull request overview

This PR extends MIGraphX’s symbolic dynamic-shape support end-to-end by exposing sym::expr through the driver, the C/C++ API surface, and Python bindings, and adds API/Python tests to validate symbolic dimension construction and ONNX parsing behavior.

Changes:

Add sym::expr / sym_expr (C API + C++ handle) and enable symbolic dynamic dimensions via dynamic_dimension(sym_expr) and is_symbolic().
Extend ONNX options and front-ends (driver + Python bindings) to enable symbolic shapes and pass dim_params.
Add new C++ and Python tests for symbolic dynamic dimensions and ONNX parsing.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
`src/driver/main.cpp`	Adds `--enable-symbolic` and supports `"name"` in dynamic-dim JSON to create symbolic dims.
`src/api/include/migraphx/migraphx.h`	Introduces C API `migraphx_sym_expr_t` and related functions; adds symbolic dynamic-dimension APIs.
`src/api/include/migraphx/migraphx.hpp`	Adds C++ `sym_expr` handle wrapper and `dynamic_dimension(sym_expr)` / `is_symbolic()` accessors.
`src/api/api.cpp`	Implements the new C API for `sym_expr`, symbolic dynamic dimensions, and ONNX option setters.
`tools/api/api.cpp`	Adds helper(s) used by generated bindings for creating symbolic variables and ONNX option setters.
`src/api/migraphx.py`	Exposes the new `migraphx_sym_expr` handle + operators and ONNX option setters in the generated API.
`src/py/migraphx_py.cpp`	Adds `migraphx.sym` submodule, symbolic `dynamic_dimension` ctor, and ONNX parse flags/params in Python.
`test/api/test_symbolic_shape.cpp`	Adds C++ API tests for symbolic dynamic dimensions and ONNX parsing behavior.
`test/api/CMakeLists.txt`	Registers the new C++ API test.
`test/py/test_symbolic_shape.py`	Adds Python tests for symbolic expressions/dimensions and ONNX parsing behavior.
`test/py/CMakeLists.txt`	Registers the new Python test.

+    auto api_error_result = migraphx::try_([&] {
+        if(out == nullptr)
+            MIGRAPHX_THROW(migraphx_status_bad_param, "Bad parameter out: Null pointer");
+        if(sym_expr == nullptr)
+            MIGRAPHX_THROW(migraphx_status_bad_param, "Bad parameter sym_expr: Null pointer");
+        auto&& api_result = (sym_expr->object).to_string();
+        auto* it = std::copy_n(api_result.begin(), std::min(api_result.size(), out_size - 1), out);
+        *it      = '\0';


        "Parse onnx file",
        py::arg("filename"),
        py::arg("default_dim_value")     = 0,


        [](const std::string& onnx_buffer,
           unsigned int default_dim_value,
           migraphx::shape::dynamic_dimension default_dyn_dim_value,
+           std::unordered_map<std::string, migraphx::shape::dynamic_dimension> dim_params,
           std::unordered_map<std::string, std::vector<std::size_t>> map_input_dims,
           std::unordered_map<std::string, std::vector<migraphx::shape::dynamic_dimension>>
               map_dyn_input_dims,


+    return sym::var(name, {static_cast<int64_t>(min), static_cast<int64_t>(max)});
+}
+
+static sym::expr make_sym_var(const char* name, size_t min, size_t max, std::set<size_t> optimals)


+    return sym::var(name, {static_cast<int64_t>(min), static_cast<int64_t>(max)});
+}
+
+static sym::expr make_sym_var(const char* name, size_t min, size_t max, std::set<size_t> optimals)


codecov · 2026-06-06T00:03:13Z

Codecov Report

❌ Patch coverage is 74.07407% with 21 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/api/api.cpp	67.21%	20 Missing ⚠️
src/api/include/migraphx/migraphx.hpp	95.00%	1 Missing ⚠️

Additional details and impacted files

@@                Coverage Diff                 @@
##           sym_onnx_parse    #4946      +/-   ##
==================================================
- Coverage           92.72%   92.69%   -0.03%     
==================================================
  Files                 592      589       -3     
  Lines               31355    31344      -11     
==================================================
- Hits                29072    29053      -19     
- Misses               2283     2291       +8

Files with missing lines	Coverage Δ
src/api/include/migraphx/migraphx.hpp	`98.91% <95.00%> (-0.14%)`	⬇️
src/api/api.cpp	`74.31% <67.21%> (+0.43%)`	⬆️

... and 5 files with indirect coverage changes

🚀 New features to boost your workflow:

❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

pfultz2 · 2026-06-07T23:27:47Z

+/**
+ * @brief Symbolic expression used to describe symbolic dynamic dimensions.
+ */
+struct sym_expr : MIGRAPHX_HANDLE_BASE(sym_expr)


We should not expose the sym_expr to the API. The symbolic symbols should be passed as a string and then we use sym::parse to convert it to a symbolic expression.

how do we set the intervals and optimals that way?

I assume thats done with the dynamic_dimension class, but now that I think about it more, it seems very clunky since the user will need to add a dynamic_dimension for the same dim_param they are setting. It seems like it would be better if the user sets a dynamic_dimension with just the interval and optimals and then we apply the symbols to it based on the onnx parsing.

this was there to allow a user to create a symbolic dynamic dimension via the API like we allow creating a range based dynamic shape currently. ONNX parsing already applies interval and optimals if you use default_dyn_dim/dim_params. This is to allow them to set the shape using map_dyn_input_dims

pfultz2 · 2026-06-07T23:28:10Z

            &migraphx_dynamic_dimension_create_min_max_optimals, min, max, opts.get_handle_ptr());
    }

+    dynamic_dimension(const sym_expr& expr) // NOLINT(google-explicit-constructor)


This should be dynamic_dimension(const std::string& expr).

pfultz2 · 2026-06-07T23:33:29Z

        call(&migraphx_onnx_options_set_use_debug_symbols, this->get_handle_ptr(), value);
    }
+
+    void set_use_symbolic_shapes(bool value = true)


I dont really like exposing this to the API like this since it should become the default and then this API does nothing and should be ignored.

shivadbhavsar added 3 commits June 5, 2026 15:08

driver and api updates for using sym shapes

e223276

Merge remote-tracking branch 'origin/sym_onnx_parse' into sym_driver

115435f

add missing api update

964ba2a

shivadbhavsar requested a review from causten as a code owner June 5, 2026 22:23

Copilot AI review requested due to automatic review settings June 5, 2026 22:23

Copilot started reviewing on behalf of shivadbhavsar June 5, 2026 22:23 View session

shivadbhavsar changed the base branch from develop to sym_onnx_parse June 5, 2026 22:23

shivadbhavsar self-assigned this Jun 5, 2026

Copilot AI reviewed Jun 5, 2026

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pfultz2 requested changes Jun 7, 2026

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pfultz2 reviewed Jun 7, 2026

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shivadbhavsar and others added 2 commits June 8, 2026 10:03

Merge branch 'sym_onnx_parse' into sym_driver

078eda4

dont expose sym api

789ad4e

shivadbhavsar requested a review from pfultz2 June 11, 2026 00:43

shivadbhavsar and others added 3 commits June 11, 2026 09:18

Merge branch 'sym_onnx_parse' into sym_driver

690b2d7

update api to use sym::scalar

35880ff

Merge remote-tracking branch 'origin/sym_onnx_parse' into sym_driver

dfb2b9d

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Driver and API updates for using sym shapes#4946

Driver and API updates for using sym shapes#4946
shivadbhavsar wants to merge 8 commits into
sym_onnx_parsefrom
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shivadbhavsar commented Jun 5, 2026 •

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shivadbhavsar commented Jun 5, 2026 •

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