Commit Graph

2 Commits

Author SHA1 Message Date
Anand Krishnamoorthi
a8a3a9809b feat!: Use num-bigint for large numbers (#500)
- Supply chain: Use the popular num-bigint crate for handling large integers
- Optimization: Handle f64, i64, u64 directly. These will be the most common instances of a number.

OPA number semantics isn't clear.
https://github.com/open-policy-agent/opa/issues/6281

As part of this change, we update the following failing tests:
- A local test that relies on what 15.3/3 evaluates to.
 With our current change, we round in a different direction than what OPA does, but consistent
 with Rust. We produce 5.1000000000000005 where as the OPA test expects 5.1.
 There is no clear definition in Rego of what the right answer is. Moreover, policies should not
 rely on exact floating point value comparison. Therefore this deviations is justified.
 The test is patched to pass.
- Another local vm test that exercised 1.1 + 2.2
- Another local vm test that exercises 5.5 - 2.2
- An OPA test that expects that a large integer number say 10e308 is printed in exponent notation.
 num-bigint does not print using scientific notation and instead prints all the digits.
 The benefit of preserving this compatibility is not clear. We skip this test.
- Doc tests that exercised handling floating point numbers with more than 15 (what f64 supports)
  digits of precision. There is no usecase for this scenario. The tests are updated to reflect
  the behavior.

Signed-off-by: Anand Krishnamoorthi <anakrish@microsoft.com>
2025-12-01 13:25:02 -06:00
Anand Krishnamoorthi
49bd3c22f3 feat!: add Rego Virtual Machine (RVM) implementation (#495)
* feat!: add Rego Virtual Machine (RVM) implementation

This commit introduces a register-based virtual machine for executing Rego
policies with bytecode-style instructions. Unlike the existing tree-walking
interpreter, the RVM compiles policies into instruction sequences that operate
on virtual registers, offering better performance and optimization potential.

Core Components:

Instruction Set Architecture:
- Define instruction types for data operations, control flow, and builtins
- Implement instruction parameter encoding and display formatting
- Add instruction parser with comprehensive test coverage

Virtual Machine Engine:
- Register-based execution model with program counter management
- Loop execution supporting iterators, comprehensions, and quantifiers
- Function call handling with argument evaluation and context management
- Rule evaluation with default value resolution and virtual data support
- Arithmetic and comparison operation implementations

Program Representation:
- Program listing builder with instruction sequencing
- Rule tree construction for organizing policy rules
- Binary and JSON serialization for compiled programs
- Recompilation support for program modification

Testing Infrastructure:
- Extensive YAML test suites covering all VM features
- Rust unit tests for VM execution and instruction parsing
- Test suites for loops, comprehensions, builtins, and control flow

BREAKING CHANGE: Introduces new VM execution path alongside interpreter

Signed-off-by: Anand Krishnamoorthi <anakrish@microsoft.com>

* docs: add detailed RVM architecture references

Introduce architecture.md explaining program artifacts, serialization, and runtime subsystems.
Document the full opcode catalog in instruction-set.md, including operands, parameter tables, and outcomes.
Walk through execution flow, stacks, and operational guidance in vm-runtime.md, tying the runtime to the new architecture docs.

Signed-off-by: Anand Krishnamoorthi <anakrish@microsoft.com>

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Signed-off-by: Anand Krishnamoorthi <anakrish@microsoft.com>
2025-11-14 11:43:19 -06:00