fix(ffi): eliminate aliasing UB + add Azure Policy JSON compilation FFI (#727)

* fix(ffi): eliminate aliasing UB via to_shared_ref migration Add to_shared_ref() helper that creates &T (shared reference) from raw pointers instead of &mut T. This eliminates undefined behavior caused by violating Rust's aliasing invariant when C# SafeHandle permits concurrent FFI calls on the same handle. With &mut T, the compiler may assume exclusive (noalias) access and reorder or elide reads/writes — a miscompilation risk when another thread holds a reference to the same object. Switching to &T removes that assumption; actual mutation is mediated by the interior RwLock inside Handle<T>, which is the sole synchronization mechanism. Migrated sites: - rvm.rs: 20 non-drop call sites - engine.rs: 30 non-drop call sites + with_unwind_guard for timer fns - compiled_policy.rs: 2 call sites - Fix null-data UB in regorus_program_deserialize_binary Drop paths retain to_ref() where exclusive access is guaranteed by the caller contract (preventing use-after-free). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> * feat(ffi): add Azure Policy JSON compilation FFI and C# bindings - AliasRegistry builder pattern: RegorusAliasRegistryBuilder (mutable, single-threaded) + RegorusAliasRegistry (immutable, Arc-wrapped) - Azure Policy JSON compilation: regorus_compile_azure_policy_rule and regorus_compile_azure_policy_definition with alias registry support - regorus_rvm_set_context for host-supplied ambient data - C# AliasRegistryBuilder and AliasRegistry classes with convenience factories (FromJson, FromManifest, Empty) - C# AzurePolicyCompiler static class for policy rule/definition compilation - Compile functions take *const RegorusAliasRegistry (read-only via to_shared_ref for concurrent compilation safety) - Fix pre-existing clippy warnings across multiple crates Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> --------- Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-08-05 02:16:11 +00:00 · 2026-05-22 12:50:16 -05:00
parent 5467cd9e69
commit 86b4a279fa
26 changed files with 1986 additions and 315 deletions
@@ -1,7 +1,7 @@
 <Project>
  <PropertyGroup>
    <ManagePackageVersionsCentrally>true</ManagePackageVersionsCentrally>
-    <RegorusPackageVersion>0.10.0</RegorusPackageVersion>
+    <RegorusPackageVersion>0.10.1</RegorusPackageVersion>
    <RegorusPackageVersionSuffix Condition="'$(VersionSuffix)' != ''">-$(VersionSuffix)</RegorusPackageVersionSuffix>
  </PropertyGroup>

@@ -150,3 +150,76 @@ const string ContextJson = """
 var allowed = RbacEngine.EvaluateCondition(Condition, ContextJson);
 Console.WriteLine($"RBAC condition allowed: {allowed}");
 ```
+
+## Azure Policy JSON Evaluation
+
+Compile and evaluate Azure Policy JSON `policyRule` definitions directly — no Rego translation required.
+The `AzurePolicyCompiler` compiles JSON policy rules into RVM programs that can be executed with the `Rvm` engine.
+
+```csharp
+using Regorus;
+
+// 1. Load alias definitions for the resource provider
+const string AliasesJson = """
+[{
+    "namespace": "Microsoft.Storage",
+    "resourceTypes": [{
+        "resourceType": "storageAccounts",
+        "aliases": [{
+            "name": "Microsoft.Storage/storageAccounts/supportsHttpsTrafficOnly",
+            "defaultPath": "properties.supportsHttpsTrafficOnly",
+            "paths": []
+        }]
+    }]
+}]
+""";
+
+using var registry = AliasRegistry.FromJson(AliasesJson);
+
+// 2. Compile a JSON policy rule (the native Azure Policy language)
+const string PolicyRule = """
+{
+    "if": {
+        "allOf": [
+            { "field": "type", "equals": "Microsoft.Storage/storageAccounts" },
+            { "field": "Microsoft.Storage/storageAccounts/supportsHttpsTrafficOnly", "equals": false }
+        ]
+    },
+    "then": { "effect": "deny" }
+}
+""";
+
+using var program = AzurePolicyCompiler.CompilePolicyRule(registry, PolicyRule);
+
+// 3. Normalize an ARM resource and evaluate
+var armResource = """
+{
+    "type": "Microsoft.Storage/storageAccounts",
+    "name": "mystorage",
+    "properties": { "supportsHttpsTrafficOnly": false }
+}
+""";
+var envelope = registry.NormalizeAndWrap(armResource);
+
+using var vm = new Rvm();
+vm.LoadProgram(program);
+vm.SetInputJson(envelope!);
+
+var result = vm.ExecuteEntryPoint("main");
+// result: {"effect": "deny"} for non-compliant, "<undefined>" for compliant
+Console.WriteLine($"Policy result: {result}");
+```
+
+**Context-dependent policies:** If your policy uses context functions like
+`subscription()`, `resourceGroup()`, or `requestContext()`, you must also set
+the VM context separately:
+
+```csharp
+// The context JSON from NormalizeAndWrap is in the input envelope,
+// but must also be provided to the VM's ambient context:
+vm.SetContextJson(contextJson);
+```
+
+You can also compile full policy definitions (with parameters) using
+`AzurePolicyCompiler.CompilePolicyDefinition()`. See
+`bindings/csharp/Regorus.Tests/AzurePolicyCompilerTests.cs` for comprehensive examples.
@@ -43,31 +43,28 @@ public class AliasRegistryTests
    [TestMethod]
    public void Create_and_dispose_succeeds()
    {
-        using var registry = new AliasRegistry();
+        using var registry = AliasRegistry.Empty();
        Assert.AreEqual(0, registry.Length);
    }

    [TestMethod]
    public void LoadJson_populates_registry()
    {
-        using var registry = new AliasRegistry();
-        registry.LoadJson(AliasesJson);
+        using var registry = AliasRegistry.FromJson(AliasesJson);
        Assert.AreEqual(1, registry.Length);
    }

    [TestMethod]
    public void LoadManifest_populates_registry()
    {
-        using var registry = new AliasRegistry();
-        registry.LoadManifest(ManifestJson);
+        using var registry = AliasRegistry.FromManifest(ManifestJson);
        Assert.AreEqual(1, registry.Length);
    }

    [TestMethod]
    public void NormalizeAndWrap_produces_envelope()
    {
-        using var registry = new AliasRegistry();
-        registry.LoadJson(AliasesJson);
+        using var registry = AliasRegistry.FromJson(AliasesJson);

        var resource = @"{
            ""name"": ""acct1"",
@@ -93,8 +90,7 @@ public class AliasRegistryTests
    [TestMethod]
    public void NormalizeAndWrap_with_context_and_parameters()
    {
-        using var registry = new AliasRegistry();
-        registry.LoadJson(AliasesJson);
+        using var registry = AliasRegistry.FromJson(AliasesJson);

        var resource = @"{
            ""name"": ""acct1"",
@@ -115,8 +111,7 @@ public class AliasRegistryTests
    [TestMethod]
    public void Denormalize_restores_properties()
    {
-        using var registry = new AliasRegistry();
-        registry.LoadJson(AliasesJson);
+        using var registry = AliasRegistry.FromJson(AliasesJson);

        var normalized = @"{
            ""name"": ""acct1"",
@@ -137,8 +132,7 @@ public class AliasRegistryTests
    [TestMethod]
    public void Round_trip_normalize_then_denormalize()
    {
-        using var registry = new AliasRegistry();
-        registry.LoadJson(AliasesJson);
+        using var registry = AliasRegistry.FromJson(AliasesJson);

        var resource = @"{
            ""name"": ""acct1"",
@@ -166,8 +160,7 @@ public class AliasRegistryTests
    [TestMethod]
    public void DataPlane_manifest_normalize()
    {
-        using var registry = new AliasRegistry();
-        registry.LoadManifest(ManifestJson);
+        using var registry = AliasRegistry.FromManifest(ManifestJson);

        var resource = @"{
            ""type"": ""Microsoft.KeyVault.Data/vaults/certificates"",
@@ -185,7 +178,7 @@ public class AliasRegistryTests
    [ExpectedException(typeof(InvalidOperationException))]
    public void LoadJson_invalid_throws()
    {
-        using var registry = new AliasRegistry();
-        registry.LoadJson("not valid json");
+        using var builder = new AliasRegistryBuilder();
+        builder.LoadJson("not valid json");
    }
 }
@@ -0,0 +1,436 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System;
+using System.Text.Json.Nodes;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Regorus;
+
+namespace Regorus.Tests;
+
+/// <summary>
+/// Tests for <see cref="AzurePolicyCompiler"/> — compiling Azure Policy JSON
+/// policyRule and policyDefinition into RVM programs and evaluating them.
+/// </summary>
+[TestClass]
+public class AzurePolicyCompilerTests
+{
+    // -----------------------------------------------------------------------
+    // Test data
+    // -----------------------------------------------------------------------
+
+    private const string StorageAliasesJson = @"[{
+        ""namespace"": ""Microsoft.Storage"",
+        ""resourceTypes"": [{
+            ""resourceType"": ""storageAccounts"",
+            ""capabilities"": ""SupportsTags, SupportsLocation"",
+            ""aliases"": [
+                {
+                    ""name"": ""Microsoft.Storage/storageAccounts/supportsHttpsTrafficOnly"",
+                    ""defaultPath"": ""properties.supportsHttpsTrafficOnly"",
+                    ""paths"": []
+                },
+                {
+                    ""name"": ""Microsoft.Storage/storageAccounts/minimumTlsVersion"",
+                    ""defaultPath"": ""properties.minimumTlsVersion"",
+                    ""paths"": []
+                }
+            ]
+        }]
+    }]";
+
+    /// <summary>Simple policy rule that checks the resource type.</summary>
+    private const string SimpleAuditRule = @"{
+        ""if"": {
+            ""field"": ""type"",
+            ""equals"": ""Microsoft.Storage/storageAccounts""
+        },
+        ""then"": { ""effect"": ""audit"" }
+    }";
+
+    /// <summary>Policy rule that uses an alias to check HTTPS-only.</summary>
+    private const string HttpsDenyRule = @"{
+        ""if"": {
+            ""allOf"": [
+                { ""field"": ""type"", ""equals"": ""Microsoft.Storage/storageAccounts"" },
+                { ""field"": ""Microsoft.Storage/storageAccounts/supportsHttpsTrafficOnly"", ""equals"": false }
+            ]
+        },
+        ""then"": { ""effect"": ""deny"" }
+    }";
+
+    /// <summary>Full policy definition with parameters.</summary>
+    private const string PolicyDefinitionWithParams = @"{
+        ""displayName"": ""Require HTTPS for storage accounts"",
+        ""policyType"": ""Custom"",
+        ""mode"": ""Indexed"",
+        ""parameters"": {
+            ""effect"": {
+                ""type"": ""String"",
+                ""defaultValue"": ""deny""
+            }
+        },
+        ""policyRule"": {
+            ""if"": {
+                ""allOf"": [
+                    { ""field"": ""type"", ""equals"": ""Microsoft.Storage/storageAccounts"" },
+                    { ""field"": ""Microsoft.Storage/storageAccounts/supportsHttpsTrafficOnly"", ""equals"": false }
+                ]
+            },
+            ""then"": { ""effect"": ""[parameters('effect')]"" }
+        }
+    }";
+
+    // -----------------------------------------------------------------------
+    // Helper
+    // -----------------------------------------------------------------------
+
+    /// <summary>
+    /// Wrap a normalized resource JSON and parameters into the input envelope
+    /// expected by compiled Azure Policy RVM programs.
+    /// </summary>
+    private static string WrapInput(string resourceJson, string parametersJson = "{}")
+    {
+        return $@"{{""resource"": {resourceJson}, ""parameters"": {parametersJson}}}";
+    }
+
+    /// <summary>
+    /// Compile a policy rule, load it into an RVM, set input, and execute.
+    /// Returns the result string from <c>ExecuteEntryPoint("main")</c>.
+    /// </summary>
+    private static string? CompileAndEval(
+        AliasRegistry? registry,
+        string policyRuleJson,
+        string inputJson)
+    {
+        using var program = AzurePolicyCompiler.CompilePolicyRule(registry, policyRuleJson);
+        using var vm = new Rvm();
+        vm.LoadProgram(program);
+        vm.SetInputJson(inputJson);
+        return vm.ExecuteEntryPoint("main");
+    }
+
+    // -----------------------------------------------------------------------
+    // CompilePolicyRule tests
+    // -----------------------------------------------------------------------
+
+    [TestMethod]
+    public void CompilePolicyRule_no_aliases_succeeds()
+    {
+        using var program = AzurePolicyCompiler.CompilePolicyRule(null, SimpleAuditRule);
+        Assert.IsNotNull(program);
+    }
+
+    [TestMethod]
+    public void CompilePolicyRule_with_aliases_succeeds()
+    {
+        using var registry = AliasRegistry.FromJson(StorageAliasesJson);
+
+        using var program = AzurePolicyCompiler.CompilePolicyRule(registry, HttpsDenyRule);
+        Assert.IsNotNull(program);
+    }
+
+    [TestMethod]
+    [ExpectedException(typeof(ArgumentNullException))]
+    public void CompilePolicyRule_null_json_throws()
+    {
+        AzurePolicyCompiler.CompilePolicyRule(null, null!);
+    }
+
+    [TestMethod]
+    [ExpectedException(typeof(InvalidOperationException))]
+    public void CompilePolicyRule_invalid_json_throws()
+    {
+        AzurePolicyCompiler.CompilePolicyRule(null, "not valid json");
+    }
+
+    // -----------------------------------------------------------------------
+    // CompilePolicyDefinition tests
+    // -----------------------------------------------------------------------
+
+    [TestMethod]
+    public void CompilePolicyDefinition_no_aliases_succeeds()
+    {
+        using var program = AzurePolicyCompiler.CompilePolicyDefinition(null, PolicyDefinitionWithParams);
+        Assert.IsNotNull(program);
+    }
+
+    [TestMethod]
+    public void CompilePolicyDefinition_with_aliases_succeeds()
+    {
+        using var registry = AliasRegistry.FromJson(StorageAliasesJson);
+
+        using var program = AzurePolicyCompiler.CompilePolicyDefinition(registry, PolicyDefinitionWithParams);
+        Assert.IsNotNull(program);
+    }
+
+    [TestMethod]
+    [ExpectedException(typeof(ArgumentNullException))]
+    public void CompilePolicyDefinition_null_json_throws()
+    {
+        AzurePolicyCompiler.CompilePolicyDefinition(null, null!);
+    }
+
+    [TestMethod]
+    [ExpectedException(typeof(InvalidOperationException))]
+    public void CompilePolicyDefinition_invalid_json_throws()
+    {
+        AzurePolicyCompiler.CompilePolicyDefinition(null, @"{""not"": ""a definition""}");
+    }
+
+    // -----------------------------------------------------------------------
+    // End-to-end evaluation tests
+    // -----------------------------------------------------------------------
+
+    [TestMethod]
+    public void Eval_simple_rule_matching_resource_returns_effect()
+    {
+        var input = WrapInput(
+            @"{""type"": ""microsoft.storage/storageaccounts""}");
+
+        var result = CompileAndEval(null, SimpleAuditRule, input);
+        Assert.IsNotNull(result, "expected a result for matching resource");
+
+        var doc = JsonNode.Parse(result!)!;
+        Assert.AreEqual("audit", doc["effect"]?.GetValue<string>(),
+            $"expected 'audit' effect, got: {result}");
+    }
+
+    [TestMethod]
+    public void Eval_simple_rule_non_matching_resource_returns_undefined()
+    {
+        var input = WrapInput(
+            @"{""type"": ""microsoft.compute/virtualmachines""}");
+
+        var result = CompileAndEval(null, SimpleAuditRule, input);
+        Assert.IsNotNull(result);
+        StringAssert.Contains(result!, "undefined",
+            "expected undefined for non-matching resource type");
+    }
+
+    [TestMethod]
+    public void Eval_alias_rule_non_compliant_returns_deny()
+    {
+        using var registry = AliasRegistry.FromJson(StorageAliasesJson);
+
+        // Non-compliant: HTTPS not enabled (normalized/lowercased form)
+        var input = WrapInput(
+            @"{""type"": ""microsoft.storage/storageaccounts"", ""supportshttpstrafficonly"": false}");
+
+        using var program = AzurePolicyCompiler.CompilePolicyRule(registry, HttpsDenyRule);
+        using var vm = new Rvm();
+        vm.LoadProgram(program);
+        vm.SetInputJson(input);
+
+        var result = vm.ExecuteEntryPoint("main");
+        Assert.IsNotNull(result);
+
+        var doc = JsonNode.Parse(result!)!;
+        Assert.AreEqual("deny", doc["effect"]?.GetValue<string>(),
+            $"expected 'deny' for non-compliant resource, got: {result}");
+    }
+
+    [TestMethod]
+    public void Eval_alias_rule_compliant_returns_undefined()
+    {
+        using var registry = AliasRegistry.FromJson(StorageAliasesJson);
+
+        // Compliant: HTTPS enabled
+        var input = WrapInput(
+            @"{""type"": ""microsoft.storage/storageaccounts"", ""supportshttpstrafficonly"": true}");
+
+        using var program = AzurePolicyCompiler.CompilePolicyRule(registry, HttpsDenyRule);
+        using var vm = new Rvm();
+        vm.LoadProgram(program);
+        vm.SetInputJson(input);
+
+        var result = vm.ExecuteEntryPoint("main");
+        Assert.IsNotNull(result);
+        StringAssert.Contains(result!, "undefined",
+            "expected undefined for compliant resource");
+    }
+
+    [TestMethod]
+    public void Eval_definition_with_default_parameters()
+    {
+        using var registry = AliasRegistry.FromJson(StorageAliasesJson);
+
+        using var program = AzurePolicyCompiler.CompilePolicyDefinition(
+            registry, PolicyDefinitionWithParams);
+        using var vm = new Rvm();
+        vm.LoadProgram(program);
+
+        // Non-compliant resource
+        var input = WrapInput(
+            @"{""type"": ""microsoft.storage/storageaccounts"", ""supportshttpstrafficonly"": false}");
+        vm.SetInputJson(input);
+
+        var result = vm.ExecuteEntryPoint("main");
+        Assert.IsNotNull(result);
+
+        var doc = JsonNode.Parse(result!)!;
+        // Default parameter value is "deny"
+        Assert.AreEqual("deny", doc["effect"]?.GetValue<string>(),
+            $"expected default 'deny' effect, got: {result}");
+    }
+
+    [TestMethod]
+    public void Eval_with_normalized_arm_resource_end_to_end()
+    {
+        using var registry = AliasRegistry.FromJson(StorageAliasesJson);
+
+        // Simulate the full production flow:
+        // 1. Start with an ARM resource
+        var armResource = @"{
+            ""type"": ""Microsoft.Storage/storageAccounts"",
+            ""name"": ""mystorage"",
+            ""location"": ""eastus"",
+            ""properties"": {
+                ""supportsHttpsTrafficOnly"": false,
+                ""minimumTlsVersion"": ""TLS1_0""
+            }
+        }";
+
+        // 2. Normalize via AliasRegistry
+        var normalizedEnvelope = registry.NormalizeAndWrap(
+            armResource,
+            apiVersion: null,
+            contextJson: "{}",
+            parametersJson: "{}");
+        Assert.IsNotNull(normalizedEnvelope);
+
+        // 3. Compile the policy rule
+        using var program = AzurePolicyCompiler.CompilePolicyRule(registry, HttpsDenyRule);
+
+        // 4. Execute
+        using var vm = new Rvm();
+        vm.LoadProgram(program);
+        vm.SetInputJson(normalizedEnvelope!);
+
+        var result = vm.ExecuteEntryPoint("main");
+        Assert.IsNotNull(result);
+
+        var doc = JsonNode.Parse(result!)!;
+        Assert.AreEqual("deny", doc["effect"]?.GetValue<string>(),
+            $"expected 'deny' for non-HTTPS storage account, got: {result}");
+    }
+
+    [TestMethod]
+    public void Eval_normalized_compliant_resource_end_to_end()
+    {
+        using var registry = AliasRegistry.FromJson(StorageAliasesJson);
+
+        var armResource = @"{
+            ""type"": ""Microsoft.Storage/storageAccounts"",
+            ""name"": ""secureastorage"",
+            ""location"": ""westus"",
+            ""properties"": {
+                ""supportsHttpsTrafficOnly"": true,
+                ""minimumTlsVersion"": ""TLS1_2""
+            }
+        }";
+
+        var normalizedEnvelope = registry.NormalizeAndWrap(
+            armResource,
+            apiVersion: null,
+            contextJson: "{}",
+            parametersJson: "{}");
+        Assert.IsNotNull(normalizedEnvelope);
+
+        using var program = AzurePolicyCompiler.CompilePolicyRule(registry, HttpsDenyRule);
+        using var vm = new Rvm();
+        vm.LoadProgram(program);
+        vm.SetInputJson(normalizedEnvelope!);
+
+        var result = vm.ExecuteEntryPoint("main");
+        Assert.IsNotNull(result);
+        StringAssert.Contains(result!, "undefined",
+            "expected undefined for compliant HTTPS storage account");
+    }
+
+    [TestMethod]
+    public void Program_can_be_serialized_and_reloaded()
+    {
+        using var program = AzurePolicyCompiler.CompilePolicyRule(null, SimpleAuditRule);
+
+        // Serialize to binary
+        var binary = program.SerializeBinary();
+        Assert.IsTrue(binary.Length > 0, "serialized program should not be empty");
+
+        // Deserialize and run
+        using var restored = Program.DeserializeBinary(binary, out var isPartial);
+        Assert.IsFalse(isPartial, "program should not be partial");
+
+        using var vm = new Rvm();
+        vm.LoadProgram(restored);
+        var input = WrapInput(@"{""type"": ""microsoft.storage/storageaccounts""}");
+        vm.SetInputJson(input);
+
+        var result = vm.ExecuteEntryPoint("main");
+        Assert.IsNotNull(result);
+        var doc = JsonNode.Parse(result!)!;
+        Assert.AreEqual("audit", doc["effect"]?.GetValue<string>());
+    }
+
+    [TestMethod]
+    public void Program_generates_listing()
+    {
+        using var program = AzurePolicyCompiler.CompilePolicyRule(null, SimpleAuditRule);
+        var listing = program.GenerateListing();
+        Assert.IsFalse(string.IsNullOrWhiteSpace(listing),
+            "generated listing should not be empty");
+    }
+
+    // -----------------------------------------------------------------------
+    // Context-dependent policy tests
+    // -----------------------------------------------------------------------
+
+    /// Policy rule that uses subscription() context function.
+    private const string ContextPolicyRule = @"{
+        ""if"": {
+            ""allOf"": [
+                { ""field"": ""type"", ""equals"": ""Microsoft.Storage/storageAccounts"" },
+                { ""value"": ""[subscription().subscriptionId]"", ""equals"": ""sub-123"" }
+            ]
+        },
+        ""then"": { ""effect"": ""deny"" }
+    }";
+
+    [TestMethod]
+    public void Eval_context_policy_with_set_context_returns_effect()
+    {
+        using var program = AzurePolicyCompiler.CompilePolicyRule(null, ContextPolicyRule);
+        using var vm = new Rvm();
+        vm.LoadProgram(program);
+
+        vm.SetContextJson(@"{""subscription"": {""subscriptionId"": ""sub-123""}}");
+
+        var input = WrapInput(
+            @"{""type"": ""microsoft.storage/storageaccounts""}");
+        vm.SetInputJson(input);
+
+        var result = vm.ExecuteEntryPoint("main");
+        Assert.IsNotNull(result);
+        var doc = JsonNode.Parse(result!)!;
+        Assert.AreEqual("deny", doc["effect"]?.GetValue<string>(),
+            $"expected 'deny' with matching context, got: {result}");
+    }
+
+    [TestMethod]
+    public void Eval_context_policy_without_context_returns_undefined()
+    {
+        using var program = AzurePolicyCompiler.CompilePolicyRule(null, ContextPolicyRule);
+        using var vm = new Rvm();
+        vm.LoadProgram(program);
+
+        // No context set — subscription() will be undefined
+        var input = WrapInput(
+            @"{""type"": ""microsoft.storage/storageaccounts""}");
+        vm.SetInputJson(input);
+
+        var result = vm.ExecuteEntryPoint("main");
+        Assert.IsNotNull(result);
+        StringAssert.Contains(result!, "undefined",
+            "expected undefined without context set");
+    }
+}
@@ -62,8 +62,7 @@ public class AzurePolicyTests
    [TestMethod]
    public void AliasRegistry_NormalizeAndWrap_produces_input_envelope()
    {
-        using var registry = new AliasRegistry();
-        registry.LoadJson(StorageAliasesJson);
+        using var registry = AliasRegistry.FromJson(StorageAliasesJson);

        var result = registry.NormalizeAndWrap(
            StorageResourceJson,
@@ -84,8 +83,7 @@ public class AzurePolicyTests
    [TestMethod]
    public void AliasRegistry_NormalizeAndWrap_flattens_properties()
    {
-        using var registry = new AliasRegistry();
-        registry.LoadJson(StorageAliasesJson);
+        using var registry = AliasRegistry.FromJson(StorageAliasesJson);

        var result = registry.NormalizeAndWrap(StorageResourceJson);
        Assert.IsNotNull(result);
@@ -107,8 +105,7 @@ public class AzurePolicyTests
    [TestMethod]
    public void AliasRegistry_NormalizeAndWrap_preserves_type_field()
    {
-        using var registry = new AliasRegistry();
-        registry.LoadJson(StorageAliasesJson);
+        using var registry = AliasRegistry.FromJson(StorageAliasesJson);

        var result = registry.NormalizeAndWrap(StorageResourceJson);
        var doc = JsonNode.Parse(result!);
@@ -125,8 +122,7 @@ public class AzurePolicyTests
    [TestMethod]
    public void AliasRegistry_NormalizeAndWrap_includes_parameters()
    {
-        using var registry = new AliasRegistry();
-        registry.LoadJson(StorageAliasesJson);
+        using var registry = AliasRegistry.FromJson(StorageAliasesJson);

        var parametersJson = @"{ ""effect"": ""Deny"" }";
        var result = registry.NormalizeAndWrap(
@@ -143,8 +139,7 @@ public class AzurePolicyTests
    [TestMethod]
    public void AliasRegistry_Denormalize_roundtrips_correctly()
    {
-        using var registry = new AliasRegistry();
-        registry.LoadJson(StorageAliasesJson);
+        using var registry = AliasRegistry.FromJson(StorageAliasesJson);

        // Normalize the ARM resource.
        var envelope = registry.NormalizeAndWrap(StorageResourceJson);
@@ -177,8 +172,7 @@ public class AzurePolicyTests
        }

        var aliasesJson = File.ReadAllText(aliasesPath);
-        using var registry = new AliasRegistry();
-        registry.LoadJson(aliasesJson);
+        using var registry = AliasRegistry.FromJson(aliasesJson);

        // The test_aliases.json file contains multiple providers.
        Assert.IsTrue(registry.Length > 0,
@@ -8,51 +8,43 @@ using Regorus.Internal;
 namespace Regorus
 {
    /// <summary>
-    /// Manages Azure Policy alias definitions used for resource normalization
+    /// Immutable Azure Policy alias registry used for resource normalization
    /// and policy compilation.
    /// </summary>
    public unsafe sealed class AliasRegistry : SafeHandleWrapper
    {
-        /// <summary>
-        /// Create an empty alias registry.
-        /// </summary>
-        public AliasRegistry()
-            : base(RegorusAliasRegistryHandle.Create(), nameof(AliasRegistry))
+        internal AliasRegistry(RegorusAliasRegistryHandle handle)
+            : base(handle, nameof(AliasRegistry))
        {
        }

        /// <summary>
-        /// Load control-plane alias data (array of ProviderAliases) from a JSON string.
+        /// Create an empty immutable alias registry.
        /// </summary>
-        /// <param name="json">JSON array of ProviderAliases (e.g. from Get-AzPolicyAlias or ResourceTypesAndAliases.json)</param>
-        public void LoadJson(string json)
+        public static AliasRegistry Empty()
        {
-            Utf8Marshaller.WithUtf8(json, jsonPtr =>
-            {
-                UseHandle(regPtr =>
-                {
-                    CheckAndDropResult(API.regorus_alias_registry_load_json(
-                        (RegorusAliasRegistry*)regPtr, (byte*)jsonPtr));
-                    return 0;
-                });
-            });
+            using var builder = new AliasRegistryBuilder();
+            return builder.Build();
        }

        /// <summary>
-        /// Load a data-plane policy manifest from a JSON string.
+        /// Create an immutable alias registry from control-plane alias JSON.
        /// </summary>
-        /// <param name="json">JSON object containing a DataPolicyManifest</param>
-        public void LoadManifest(string json)
+        public static AliasRegistry FromJson(string json)
        {
-            Utf8Marshaller.WithUtf8(json, jsonPtr =>
-            {
-                UseHandle(regPtr =>
-                {
-                    CheckAndDropResult(API.regorus_alias_registry_load_manifest(
-                        (RegorusAliasRegistry*)regPtr, (byte*)jsonPtr));
-                    return 0;
-                });
-            });
+            using var builder = new AliasRegistryBuilder();
+            builder.LoadJson(json);
+            return builder.Build();
+        }
+
+        /// <summary>
+        /// Create an immutable alias registry from a data-plane manifest JSON document.
+        /// </summary>
+        public static AliasRegistry FromManifest(string json)
+        {
+            using var builder = new AliasRegistryBuilder();
+            builder.LoadManifest(json);
+            return builder.Build();
        }

        /// <summary>
@@ -74,11 +66,6 @@ namespace Regorus
        /// Normalize an ARM resource JSON and wrap it into the standard input envelope
        /// expected by a compiled Azure Policy program.
        /// </summary>
-        /// <param name="resourceJson">Raw ARM resource JSON</param>
-        /// <param name="apiVersion">API version string (e.g. "2023-01-01"), or null to use default alias paths</param>
-        /// <param name="contextJson">Additional context JSON object (pass "{}" if none)</param>
-        /// <param name="parametersJson">Policy parameter values JSON (pass "{}" if none)</param>
-        /// <returns>JSON string: { "resource": &lt;normalized&gt;, "context": &lt;context&gt;, "parameters": &lt;params&gt; }</returns>
        public string? NormalizeAndWrap(string resourceJson, string? apiVersion = null, string contextJson = "{}", string parametersJson = "{}")
        {
            return Utf8Marshaller.WithUtf8(resourceJson, resPtr =>
@@ -96,27 +83,22 @@ namespace Regorus
                                        (byte*)ctxPtr, (byte*)paramsPtr));
                            });
                        }
-                        else
-                        {
-                            return Utf8Marshaller.WithUtf8(apiVersion, apiPtr =>
-                                UseHandle(regPtr =>
-                                {
-                                    return ResultHelpers.GetStringResult(
-                                        API.regorus_alias_registry_normalize_and_wrap(
-                                            (RegorusAliasRegistry*)regPtr,
-                                            (byte*)resPtr, (byte*)apiPtr,
-                                            (byte*)ctxPtr, (byte*)paramsPtr));
-                                }));
-                        }
+
+                        return Utf8Marshaller.WithUtf8(apiVersion, apiPtr =>
+                            UseHandle(regPtr =>
+                            {
+                                return ResultHelpers.GetStringResult(
+                                    API.regorus_alias_registry_normalize_and_wrap(
+                                        (RegorusAliasRegistry*)regPtr,
+                                        (byte*)resPtr, (byte*)apiPtr,
+                                        (byte*)ctxPtr, (byte*)paramsPtr));
+                            }));
                    })));
        }

        /// <summary>
        /// Denormalize a previously-normalized resource JSON back to ARM format.
        /// </summary>
-        /// <param name="normalizedJson">The normalized resource JSON</param>
-        /// <param name="apiVersion">API version string, or null to use default alias paths</param>
-        /// <returns>Denormalized ARM JSON string</returns>
        public string? Denormalize(string normalizedJson, string? apiVersion = null)
        {
            return Utf8Marshaller.WithUtf8(normalizedJson, normPtr =>
@@ -131,23 +113,16 @@ namespace Regorus
                                (byte*)normPtr, null));
                    });
                }
-                else
-                {
-                    return Utf8Marshaller.WithUtf8(apiVersion, apiPtr =>
-                        UseHandle(regPtr =>
-                        {
-                            return ResultHelpers.GetStringResult(
-                                API.regorus_alias_registry_denormalize(
-                                    (RegorusAliasRegistry*)regPtr,
-                                    (byte*)normPtr, (byte*)apiPtr));
-                        }));
-                }
-            });
-        }

-        private static string? CheckAndDropResult(RegorusResult result)
-        {
-            return ResultHelpers.GetStringResult(result);
+                return Utf8Marshaller.WithUtf8(apiVersion, apiPtr =>
+                    UseHandle(regPtr =>
+                    {
+                        return ResultHelpers.GetStringResult(
+                            API.regorus_alias_registry_denormalize(
+                                (RegorusAliasRegistry*)regPtr,
+                                (byte*)normPtr, (byte*)apiPtr));
+                    }));
+            });
        }
    }
 }
@@ -0,0 +1,69 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System;
+using Regorus.Internal;
+
+#nullable enable
+namespace Regorus
+{
+    /// <summary>
+    /// Mutable, single-threaded builder for <see cref="AliasRegistry"/>.
+    /// Load alias data, then call <see cref="Build"/> to freeze the registry.
+    /// </summary>
+    public unsafe sealed class AliasRegistryBuilder : SafeHandleWrapper
+    {
+        /// <summary>
+        /// Create an empty alias registry builder.
+        /// </summary>
+        public AliasRegistryBuilder()
+            : base(RegorusAliasRegistryBuilderHandle.Create(), nameof(AliasRegistryBuilder))
+        {
+        }
+
+        /// <summary>
+        /// Load control-plane alias data (array of ProviderAliases) from a JSON string.
+        /// </summary>
+        public void LoadJson(string json)
+        {
+            Utf8Marshaller.WithUtf8(json, jsonPtr =>
+            {
+                UseHandle(builderPtr =>
+                {
+                    ResultHelpers.GetStringResult(API.regorus_alias_registry_builder_load_json(
+                        (RegorusAliasRegistryBuilder*)builderPtr,
+                        (byte*)jsonPtr));
+                });
+            });
+        }
+
+        /// <summary>
+        /// Load a data-plane policy manifest from a JSON string.
+        /// </summary>
+        public void LoadManifest(string json)
+        {
+            Utf8Marshaller.WithUtf8(json, jsonPtr =>
+            {
+                UseHandle(builderPtr =>
+                {
+                    ResultHelpers.GetStringResult(API.regorus_alias_registry_builder_load_manifest(
+                        (RegorusAliasRegistryBuilder*)builderPtr,
+                        (byte*)jsonPtr));
+                });
+            });
+        }
+
+        /// <summary>
+        /// Freeze the builder into an immutable, thread-safe alias registry.
+        /// </summary>
+        public AliasRegistry Build()
+        {
+            return UseHandle(builderPtr =>
+            {
+                var registryPtr = ResultHelpers.GetPointerResult(
+                    API.regorus_alias_registry_builder_build((RegorusAliasRegistryBuilder*)builderPtr));
+                return new AliasRegistry(RegorusAliasRegistryHandle.FromPointer(registryPtr));
+            });
+        }
+    }
+}
@@ -0,0 +1,183 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System;
+using Regorus.Internal;
+
+#nullable enable
+namespace Regorus
+{
+    /// <summary>
+    /// Provides static methods for compiling Azure Policy JSON definitions
+    /// into RVM programs that can be executed by <see cref="Rvm"/>.
+    /// </summary>
+    /// <remarks>
+    /// <para>
+    /// This class bridges the gap between Azure Policy JSON (the native
+    /// Azure policy language with <c>policyRule</c>, <c>field</c>,
+    /// <c>equals</c>, etc.) and Regorus's RVM execution engine.
+    /// </para>
+    ///
+    /// <para>
+    /// <b>Typical workflow:</b>
+    /// </para>
+    /// <list type="number">
+    /// <item>Load alias definitions with <see cref="AliasRegistryBuilder"/> and freeze them into an <see cref="AliasRegistry"/>.</item>
+    /// <item>Normalize the ARM resource via <see cref="AliasRegistry.NormalizeAndWrap"/>.</item>
+    /// <item>Compile the JSON policyRule with <see cref="CompilePolicyRule"/> or the
+    ///        full definition with <see cref="CompilePolicyDefinition"/>.</item>
+    /// <item>Execute the resulting <see cref="Program"/> in an <see cref="Rvm"/>
+    ///        instance with the normalized input.</item>
+    /// </list>
+    ///
+    /// <para>
+    /// <b>Context-dependent policies:</b> Policies that use context functions
+    /// such as <c>subscription()</c>, <c>resourceGroup()</c>, or
+    /// <c>requestContext()</c> require the VM context to be set separately via
+    /// <see cref="Rvm.SetContextJson"/> before execution. The context JSON
+    /// returned by <see cref="AliasRegistry.NormalizeAndWrap"/> is passed as
+    /// <c>input.context</c> but is <b>not</b> automatically wired into the VM's
+    /// ambient context — the caller must do both:
+    /// <c>vm.SetInputJson(envelope)</c> and <c>vm.SetContextJson(contextJson)</c>.
+    /// </para>
+    /// </remarks>
+    public static unsafe class AzurePolicyCompiler
+    {
+        /// <summary>
+        /// Compile an Azure Policy JSON policy rule into an RVM <see cref="Program"/>.
+        /// </summary>
+        /// <param name="aliasRegistry">
+        /// Alias registry for resolving fully-qualified alias names in field
+        /// references.  Pass <c>null</c> if no alias resolution is needed.
+        /// <para>
+        /// <b>Warning:</b> When <c>null</c>, alias field references compile as raw
+        /// property paths and will silently produce incorrect evaluation results for
+        /// policies that use aliases.  Modify/Append effect policies will also skip
+        /// the compile-time modifiability validation.  Only pass <c>null</c> when the
+        /// policy is known to contain no alias references (e.g. simple type/location
+        /// checks or unit-test scenarios).
+        /// </para>
+        /// </param>
+        /// <param name="policyRuleJson">
+        /// JSON string containing the policyRule object, e.g.
+        /// <c>{ "if": { "field": "type", "equals": "..." }, "then": { "effect": "deny" } }</c>
+        /// </param>
+        /// <returns>
+        /// A compiled <see cref="Program"/> ready to be loaded into an
+        /// <see cref="Rvm"/> instance.
+        /// </returns>
+        /// <exception cref="ArgumentNullException">
+        /// Thrown when <paramref name="policyRuleJson"/> is <c>null</c>.
+        /// </exception>
+        /// <exception cref="Exception">
+        /// Thrown when parsing or compilation fails.
+        /// </exception>
+        public static Program CompilePolicyRule(AliasRegistry? aliasRegistry, string policyRuleJson)
+        {
+            if (policyRuleJson is null)
+            {
+                throw new ArgumentNullException(nameof(policyRuleJson));
+            }
+
+            return Utf8Marshaller.WithUtf8(policyRuleJson, rulePtr =>
+            {
+                if (aliasRegistry is null)
+                {
+                    var result = API.regorus_compile_azure_policy_rule(
+                        null, (byte*)rulePtr);
+                    return GetProgramResult(result);
+                }
+                else
+                {
+                    return aliasRegistry.UseHandleForInterop(regPtr =>
+                    {
+                        var result = API.regorus_compile_azure_policy_rule(
+                            (RegorusAliasRegistry*)regPtr, (byte*)rulePtr);
+                        return GetProgramResult(result);
+                    });
+                }
+            });
+        }
+
+        /// <summary>
+        /// Compile a full Azure Policy definition JSON into an RVM <see cref="Program"/>.
+        /// </summary>
+        /// <param name="aliasRegistry">
+        /// Alias registry for resolving fully-qualified alias names in field
+        /// references.  Pass <c>null</c> if no alias resolution is needed.
+        /// <para>
+        /// <b>Warning:</b> When <c>null</c>, alias field references compile as raw
+        /// property paths and will silently produce incorrect evaluation results for
+        /// policies that use aliases.  Modify/Append effect policies will also skip
+        /// the compile-time modifiability validation.  Only pass <c>null</c> when the
+        /// policy is known to contain no alias references (e.g. simple type/location
+        /// checks or unit-test scenarios).
+        /// </para>
+        /// </param>
+        /// <param name="policyDefinitionJson">
+        /// JSON string containing the full policy definition, which includes
+        /// <c>policyRule</c>, <c>parameters</c>, <c>displayName</c>, etc.
+        /// Accepted in both wrapped and unwrapped forms.
+        /// </param>
+        /// <returns>
+        /// A compiled <see cref="Program"/> ready to be loaded into an
+        /// <see cref="Rvm"/> instance.
+        /// </returns>
+        /// <exception cref="ArgumentNullException">
+        /// Thrown when <paramref name="policyDefinitionJson"/> is <c>null</c>.
+        /// </exception>
+        /// <exception cref="Exception">
+        /// Thrown when parsing or compilation fails.
+        /// </exception>
+        public static Program CompilePolicyDefinition(AliasRegistry? aliasRegistry, string policyDefinitionJson)
+        {
+            if (policyDefinitionJson is null)
+            {
+                throw new ArgumentNullException(nameof(policyDefinitionJson));
+            }
+
+            return Utf8Marshaller.WithUtf8(policyDefinitionJson, defnPtr =>
+            {
+                if (aliasRegistry is null)
+                {
+                    var result = API.regorus_compile_azure_policy_definition(
+                        null, (byte*)defnPtr);
+                    return GetProgramResult(result);
+                }
+                else
+                {
+                    return aliasRegistry.UseHandleForInterop(regPtr =>
+                    {
+                        var result = API.regorus_compile_azure_policy_definition(
+                            (RegorusAliasRegistry*)regPtr, (byte*)defnPtr);
+                        return GetProgramResult(result);
+                    });
+                }
+            });
+        }
+
+        private static Program GetProgramResult(RegorusResult result)
+        {
+            try
+            {
+                if (result.status != RegorusStatus.Ok)
+                {
+                    var message = Utf8Marshaller.FromUtf8(result.error_message);
+                    throw result.status.CreateException(message);
+                }
+
+                if (result.data_type != RegorusDataType.Pointer || result.pointer_value == null)
+                {
+                    throw new Exception("Expected program pointer but got different data type");
+                }
+
+                var handle = RegorusProgramHandle.FromPointer((IntPtr)result.pointer_value);
+                return new Program(handle);
+            }
+            finally
+            {
+                API.regorus_result_drop(result);
+            }
+        }
+    }
+}
@@ -178,6 +178,14 @@ namespace Regorus.Internal
        [DllImport(LibraryName, EntryPoint = "regorus_rvm_set_input", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
        internal static extern RegorusResult regorus_rvm_set_input(RegorusRvm* vm, byte* input_json);

+        /// <summary>
+        /// Set the context document for the RVM.
+        /// The context provides host-supplied ambient data (e.g. resourceGroup(), subscription())
+        /// that Azure Policy functions can access.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_rvm_set_context", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_rvm_set_context(RegorusRvm* vm, byte* context_json);
+
        /// <summary>
        /// Execute the program.
        /// </summary>
@@ -490,6 +498,20 @@ namespace Regorus.Internal
        [DllImport(LibraryName, EntryPoint = "regorus_compile_policy_for_target", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
        internal static extern RegorusResult regorus_compile_policy_for_target(byte* data_json, RegorusPolicyModule* modules, UIntPtr modules_len);

+        /// <summary>
+        /// Compile an Azure Policy JSON policy rule into an RVM program.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_compile_azure_policy_rule", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_compile_azure_policy_rule(
+            RegorusAliasRegistry* registry, byte* policy_rule_json);
+
+        /// <summary>
+        /// Compile a full Azure Policy definition JSON into an RVM program.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_compile_azure_policy_definition", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_compile_azure_policy_definition(
+            RegorusAliasRegistry* registry, byte* policy_definition_json);
+
        #endregion

        #region Compiled Policy Methods
@@ -673,10 +695,34 @@ namespace Regorus.Internal
        #region Alias Registry Methods

        /// <summary>
-        /// Create a new, empty AliasRegistry.
+        /// Create a new alias registry builder.
        /// </summary>
-        [DllImport(LibraryName, EntryPoint = "regorus_alias_registry_new", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
-        internal static extern RegorusAliasRegistry* regorus_alias_registry_new();
+        [DllImport(LibraryName, EntryPoint = "regorus_alias_registry_builder_new", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusAliasRegistryBuilder* regorus_alias_registry_builder_new();
+
+        /// <summary>
+        /// Drop an alias registry builder.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_alias_registry_builder_drop", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern void regorus_alias_registry_builder_drop(RegorusAliasRegistryBuilder* builder);
+
+        /// <summary>
+        /// Load control-plane alias data into the builder.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_alias_registry_builder_load_json", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_alias_registry_builder_load_json(RegorusAliasRegistryBuilder* builder, byte* json);
+
+        /// <summary>
+        /// Load a data-plane policy manifest into the builder.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_alias_registry_builder_load_manifest", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_alias_registry_builder_load_manifest(RegorusAliasRegistryBuilder* builder, byte* json);
+
+        /// <summary>
+        /// Freeze a builder into an immutable alias registry.
+        /// </summary>
+        [DllImport(LibraryName, EntryPoint = "regorus_alias_registry_builder_build", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+        internal static extern RegorusResult regorus_alias_registry_builder_build(RegorusAliasRegistryBuilder* builder);

        /// <summary>
        /// Drop an AliasRegistry.
@@ -684,18 +730,6 @@ namespace Regorus.Internal
        [DllImport(LibraryName, EntryPoint = "regorus_alias_registry_drop", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
        internal static extern void regorus_alias_registry_drop(RegorusAliasRegistry* registry);

-        /// <summary>
-        /// Load control-plane alias data (array of ProviderAliases) into the registry.
-        /// </summary>
-        [DllImport(LibraryName, EntryPoint = "regorus_alias_registry_load_json", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
-        internal static extern RegorusResult regorus_alias_registry_load_json(RegorusAliasRegistry* registry, byte* json);
-
-        /// <summary>
-        /// Load a data-plane policy manifest into the registry.
-        /// </summary>
-        [DllImport(LibraryName, EntryPoint = "regorus_alias_registry_load_manifest", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
-        internal static extern RegorusResult regorus_alias_registry_load_manifest(RegorusAliasRegistry* registry, byte* json);
-
        /// <summary>
        /// Return the number of resource types loaded in the alias registry.
        /// </summary>
@@ -923,6 +957,14 @@ namespace Regorus.Internal
        public byte* content;
    }

+    /// <summary>
+    /// Wrapper for AliasRegistryBuilder.
+    /// </summary>
+    [StructLayout(LayoutKind.Sequential)]
+    internal unsafe partial struct RegorusAliasRegistryBuilder
+    {
+    }
+
    /// <summary>
    /// Wrapper for AliasRegistry.
    /// </summary>
@@ -15,7 +15,7 @@ namespace Regorus
    /// </summary>
    public unsafe sealed class Program : SafeHandleWrapper
    {
-        private Program(RegorusProgramHandle handle)
+        internal Program(RegorusProgramHandle handle)
            : base(handle, nameof(Program))
        {
        }
@@ -69,5 +69,29 @@ namespace Regorus.Internal
                API.regorus_result_drop(result);
            }
        }
+
+
+        internal static IntPtr GetPointerResult(RegorusResult result)
+        {
+            try
+            {
+                if (result.status != RegorusStatus.Ok)
+                {
+                    var message = Utf8Marshaller.FromUtf8(result.error_message);
+                    throw result.status.CreateException(message);
+                }
+
+                if (result.data_type != RegorusDataType.Pointer || result.pointer_value == null)
+                {
+                    throw new InvalidOperationException("Expected pointer result.");
+                }
+
+                return (IntPtr)result.pointer_value;
+            }
+            finally
+            {
+                API.regorus_result_drop(result);
+            }
+        }
    }
 }
@@ -106,6 +106,24 @@ namespace Regorus
            });
        }

+        /// <summary>
+        /// Set the context document for the VM.
+        /// The context provides host-supplied ambient data (e.g. resourceGroup(),
+        /// subscription()) that Azure Policy functions can access via LoadContext
+        /// instructions.
+        /// </summary>
+        public void SetContextJson(string contextJson)
+        {
+            Utf8Marshaller.WithUtf8(contextJson, contextPtr =>
+            {
+                UseHandle(vmPtr =>
+                {
+                    CheckAndDropResult(API.regorus_rvm_set_context((RegorusRvm*)vmPtr, (byte*)contextPtr));
+                    return 0;
+                });
+            });
+        }
+
        /// <summary>
        /// Set the execution mode (0 = run-to-completion, 1 = suspendable).
        /// </summary>
@@ -184,28 +184,48 @@ namespace Regorus
        }
    }

+    internal sealed class RegorusAliasRegistryBuilderHandle : SafeHandleZeroOrMinusOneIsInvalid
+    {
+        private RegorusAliasRegistryBuilderHandle() : base(ownsHandle: true)
+        {
+        }
+
+        internal static RegorusAliasRegistryBuilderHandle Create()
+        {
+            unsafe
+            {
+                var raw = Internal.API.regorus_alias_registry_builder_new();
+                if (raw is null)
+                {
+                    throw new InvalidOperationException("Failed to create Regorus alias registry builder.");
+                }
+
+                var handle = new RegorusAliasRegistryBuilderHandle();
+                handle.SetHandle((IntPtr)raw);
+                return handle;
+            }
+        }
+
+        protected override bool ReleaseHandle()
+        {
+            if (!IsInvalid)
+            {
+                unsafe
+                {
+                    Internal.API.regorus_alias_registry_builder_drop((Internal.RegorusAliasRegistryBuilder*)handle);
+                }
+                SetHandle(IntPtr.Zero);
+            }
+            return true;
+        }
+    }
+
    internal sealed class RegorusAliasRegistryHandle : SafeHandleZeroOrMinusOneIsInvalid
    {
        private RegorusAliasRegistryHandle() : base(ownsHandle: true)
        {
        }

-        internal static RegorusAliasRegistryHandle Create()
-        {
-            unsafe
-            {
-                var raw = Internal.API.regorus_alias_registry_new();
-                if (raw is null)
-                {
-                    throw new InvalidOperationException("Failed to create Regorus alias registry.");
-                }
-
-                var handle = new RegorusAliasRegistryHandle();
-                handle.SetHandle((IntPtr)raw);
-                return handle;
-            }
-        }
-
        internal static RegorusAliasRegistryHandle FromPointer(IntPtr pointer)
        {
            if (pointer == IntPtr.Zero)
@@ -232,6 +232,9 @@ allow if {

        Console.WriteLine("\n8. RVM host await (suspend/resume):");
        DemonstrateRvmHostAwait();
+
+        Console.WriteLine("\n9. Azure Policy JSON compilation:");
+        DemonstrateAzurePolicyJsonCompilation();
    }

    static void DemonstrateConcurrentEvaluation(Regorus.CompiledPolicy compiledPolicy)
@@ -492,4 +495,80 @@ allow if {
        var resumed = vm.Resume("{\"tier\":\"gold\"}");
        Console.WriteLine($"HostAwait resumed result: {resumed}");
    }
+
+    // Azure Policy JSON constants
+    private const string STORAGE_ALIASES_JSON = @"[{
+        ""namespace"": ""Microsoft.Storage"",
+        ""resourceTypes"": [{
+            ""resourceType"": ""storageAccounts"",
+            ""capabilities"": ""SupportsTags, SupportsLocation"",
+            ""aliases"": [
+                {
+                    ""name"": ""Microsoft.Storage/storageAccounts/supportsHttpsTrafficOnly"",
+                    ""defaultPath"": ""properties.supportsHttpsTrafficOnly"",
+                    ""paths"": []
+                }
+            ]
+        }]
+    }]";
+
+    private const string HTTPS_DENY_RULE = @"{
+        ""if"": {
+            ""allOf"": [
+                { ""field"": ""type"", ""equals"": ""Microsoft.Storage/storageAccounts"" },
+                { ""field"": ""Microsoft.Storage/storageAccounts/supportsHttpsTrafficOnly"", ""equals"": false }
+            ]
+        },
+        ""then"": { ""effect"": ""deny"" }
+    }";
+
+    static void DemonstrateAzurePolicyJsonCompilation()
+    {
+        // 1. Set up alias registry
+        using var registry = Regorus.AliasRegistry.FromJson(STORAGE_ALIASES_JSON);
+        Console.WriteLine("Loaded storage account aliases");
+
+        // 2. Compile the JSON policy rule directly (no Rego needed)
+        using var program = Regorus.AzurePolicyCompiler.CompilePolicyRule(registry, HTTPS_DENY_RULE);
+        Console.WriteLine("Compiled Azure Policy JSON rule to RVM program");
+
+        // 3. Normalize an ARM resource
+        var armResource = @"{
+            ""type"": ""Microsoft.Storage/storageAccounts"",
+            ""name"": ""insecurestorage"",
+            ""location"": ""eastus"",
+            ""properties"": { ""supportsHttpsTrafficOnly"": false }
+        }";
+        var envelope = registry.NormalizeAndWrap(armResource, apiVersion: null, contextJson: "{}", parametersJson: "{}");
+        Console.WriteLine($"Normalized ARM resource to evaluation envelope");
+
+        // 4. Execute in the RVM
+        //    Note: For policies using context functions (subscription(), resourceGroup()),
+        //    call vm.SetContextJson(contextJson) before execution. The context from
+        //    NormalizeAndWrap is in the envelope but must also be set on the VM separately.
+        using var vm = new Regorus.Rvm();
+        vm.LoadProgram(program);
+        vm.SetInputJson(envelope!);
+        // vm.SetContextJson(contextJson); // ← required for context-dependent policies
+        var result = vm.ExecuteEntryPoint("main");
+        Console.WriteLine($"Evaluation result (non-compliant): {result}");
+
+        // 5. Test with a compliant resource
+        var compliantResource = @"{
+            ""type"": ""Microsoft.Storage/storageAccounts"",
+            ""name"": ""securestorage"",
+            ""location"": ""eastus"",
+            ""properties"": { ""supportsHttpsTrafficOnly"": true }
+        }";
+        var compliantEnvelope = registry.NormalizeAndWrap(compliantResource, apiVersion: null, contextJson: "{}", parametersJson: "{}");
+        using var vm2 = new Regorus.Rvm();
+        vm2.LoadProgram(program);
+        vm2.SetInputJson(compliantEnvelope!);
+        var compliantResult = vm2.ExecuteEntryPoint("main");
+        Console.WriteLine($"Evaluation result (compliant): {compliantResult}");
+
+        // 6. Demonstrate program serialization
+        var binary = program.SerializeBinary();
+        Console.WriteLine($"Serialized program size: {binary.Length} bytes");
+    }
 }