Semantic Abstract MachineSAM v4.3

SAM‑style gates describe the verification model: behavior-gated checks that confirm preservation before a route is claimed publicly.

Executes and verifies semantic preservation of the USG step by step via a SAM‑style harness.

Verification Harness: Performs execution/inference-based review via a SAM‑style harness.

Machine Definition

Semantic program interpretation through state-based execution model

State Structure

SAM maintains a state defined as a 5-tuple, where each state element is responsible for a specific aspect of the execution process.

S = (N, E, C, M, O)

Current Node (N)

Identifier of the currently executing semantic atom

Environment (E)

Environment stack managing identifier-value bindings

Continuation (C)

Stack representing the continuation of future computations

Memory (M)

Abstract heap managing mutable state and allocated objects

Execution Model

Step-by-step execution process directly interpreting semantic atoms

Execution Steps

  • 1. Acquire semantic atom from current node
  • 2. Select execution rule based on atom type
  • 3. Update environment and memory state
  • 4. Transition to next execution node
TOPAZ
1// SAM execution function example
2type SAMState = {
3    currentNode: int,
4    environment: EnvironmentType,
5    continuation: Array<string>
6}
7
8function executeStep(state: SAMState, graph: USG) -> Result<SAMState, Error> {
9    let currentAtom = graph.getAtom(state.currentNode)?
10
11    match currentAtom.kind {
12        case "Binding" => {
13            let value = evaluateExpression(currentAtom.expression, state)?
14            let nextEnvironment = state.environment.bind(currentAtom.identifier, value)
15            Ok(state{ environment: nextEnvironment, currentNode: state.currentNode + 1 })
16        }
17        case "Conditional" => {
18            let conditionResult = evaluateExpression(currentAtom.condition, state)?
19            let nextNode = if conditionResult.isTruthy() { currentAtom.trueNode } else { currentAtom.falseNode }
20            Ok(state{ currentNode: nextNode })
21        }
22        case _ => Ok(state)
23    }
24}

Memory Management

Conceptual abstractions describing language-specific memory semantics

Abstract Heap Model

Model describing allocation/ownership/lifetime concepts across languages, described at a conceptual level.

Garbage Collection

Describes reachability/lifetime concepts from a visualization/analysis perspective.

Type Safety

Conceptually describes use of type hints and region labels

Optimization Engine

Advanced program optimization utilizing semantic information

Optimization Techniques

  • Semantic constant propagation and folding
  • Dead code elimination and unreachable code detection
  • Semantic-based parallelization analysis support
  • Memory access pattern optimization
TOPAZ
1// Optimization hints structure example
2type OptimizationHints = {
3    inlineCandidates: Array<int>,
4    parallelRegions: Array<string>,
5    constantValues: Map<string, int>,
6    memoryPatterns: Array<string>
7}
8
9function applyOptimizations(graph: USG, hints: OptimizationHints) -> USG {
10    let afterConstants = propagateConstants(graph, hints.constantValues)
11    let afterInlining = applyInlining(afterConstants, hints.inlineCandidates)
12    let afterParallel = applyParallelization(afterInlining, hints.parallelRegions)
13    return applyMemoryOptimization(afterParallel, hints.memoryPatterns)
14}
15
16let hints = analyzeOptimizations(usg)
17let optimized = applyOptimizations(usg, hints)

Runtime System

Runtime support system for efficient execution

Dynamic Type System

Maintains and validates type information at runtime to ensure type safety while supporting flexible execution

Exception Handling

Provides consistent error handling model by integrating language-specific exception handling mechanisms

Debugging Support

Provides debugging information at semantic level and execution tracing functionality

Verification & Execution Policy

Semantic preservation verification system through SAM‑style harness

Preservation Axioms (Phase-1)

Basic Control Flow

Semantic preservation of sequential execution, conditional branching, and iteration structures

Pure Expressions

Deterministic execution of side-effect-free computation and data transformation

Explicit Exception Boundaries

Exception propagation and handling in try/catch/finally structures

Typical Higher-Order Operations

Semantic preservation of functional patterns like map, filter, fold

Non-Preservation Areas

Non-deterministic I/O

External interactions like file system, network, user input

Platform-dependent UB

Undefined behavior and implementation-specific differences

Fine-grained Memory Model

Language-specific memory ordering and concurrency details

Non-standard Extensions

Language-specific features and compiler extensions

SAM‑style Harness

Segment Review

Step-by-step review of semantic preservation via execution/inference

Reference Architecture Based

Consistent verification environment through standardized SAM implementation

Core Components

Relationship between SAM and other core components of Core Semantic Kernel

Universal Semantic Graph →Semantic Atoms →Visualization Standards →