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//------------------------------------------------------------------------------
// <copyright file="XmlIlGenerator.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
// <owner current="true" primary="true">Microsoft</owner>
// <owner current="false">Microsoft</owner>
//------------------------------------------------------------------------------
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Reflection;
using System.Reflection.Emit;
using System.Security;
using System.Xml.XPath;
using System.Xml.Xsl.IlGen;
using System.Xml.Xsl.Qil;
using System.Xml.Xsl.Runtime;
using System.Runtime.Versioning;
namespace System.Xml.Xsl {
internal delegate void ExecuteDelegate(XmlQueryRuntime runtime);
/// <summary>
/// This internal class is the entry point for creating Msil assemblies from QilExpression.
/// </summary>
/// <remarks>
/// Generate will return an AssemblyBuilder with the following setup:
/// Assembly Name = "MS.Internal.Xml.CompiledQuery"
/// Module Dll Name = "MS.Internal.Xml.CompiledQuery.dll"
/// public class MS.Internal.Xml.CompiledQuery.Test {
/// public static void Execute(XmlQueryRuntime runtime);
/// public static void Root(XmlQueryRuntime runtime);
/// private static ... UserMethod1(XmlQueryRuntime runtime, ...);
/// ...
/// private static ... UserMethodN(XmlQueryRuntime runtime, ...);
/// }
///
/// XmlILGenerator incorporates a number of different technologies in order to generate efficient code that avoids caching
/// large result sets in memory:
///
/// 1. Code Iterators - Query results are computed using a set of composable, interlocking iterators that alone perform a
/// simple task, but together execute complex queries. The iterators are actually little blocks of code
/// that are connected to each other using a series of jumps. Because each iterator is not instantiated
/// as a separate object, the number of objects and number of function calls is kept to a minimum during
/// execution. Also, large result sets are often computed incrementally, with each iterator performing one step in a
/// pipeline of sequence items.
///
/// 2. Analyzers - During code generation, QilToMsil traverses the semantic tree representation of the query (QIL) several times.
/// As visits to each node in the tree start and end, various Analyzers are invoked. These Analyzers incrementally
/// collect and store information that is later used to generate faster and smaller code.
/// </remarks>
internal class XmlILGenerator {
private QilExpression qil;
private GenerateHelper helper;
private XmlILOptimizerVisitor optVisitor;
private XmlILVisitor xmlIlVisitor;
private XmlILModule module;
/// <summary>
/// Always output debug information in debug mode.
/// </summary>
public XmlILGenerator() {
}
/// <summary>
/// Given the logical query plan (QilExpression) generate a physical query plan (MSIL) that can be executed.
/// </summary>
// SxS Note: The way the trace file names are created (hardcoded) is NOT SxS safe. However the files are
// created only for internal tracing purposes. In addition XmlILTrace class is not compiled into retail
// builds. As a result it is fine to suppress the FxCop SxS warning.
[ResourceConsumption(ResourceScope.Machine, ResourceScope.Machine)]
[ResourceExposure(ResourceScope.None)]
public XmlILCommand Generate(QilExpression query, TypeBuilder typeBldr) {
this.qil = query;
bool useLRE = (
!this.qil.IsDebug &&
(typeBldr == null)
#if DEBUG
&& !XmlILTrace.IsEnabled // Dump assembly to disk; can't do this when using LRE
#endif
);
bool emitSymbols = this.qil.IsDebug;
// In debug code, ensure that input QIL is correct
QilValidationVisitor.Validate(this.qil);
#if DEBUG
// Trace Qil before optimization
XmlILTrace.WriteQil(this.qil, "qilbefore.xml");
// Trace optimizations
XmlILTrace.TraceOptimizations(this.qil, "qilopt.xml");
#endif
// Optimize and annotate the Qil graph
this.optVisitor = new XmlILOptimizerVisitor(this.qil, !this.qil.IsDebug);
this.qil = this.optVisitor.Optimize();
// In debug code, ensure that output QIL is correct
QilValidationVisitor.Validate(this.qil);
#if DEBUG
// Trace Qil after optimization
XmlILTrace.WriteQil(this.qil, "qilafter.xml");
#endif
XmlILModule.CreateModulePermissionSet.Assert();
// Create module in which methods will be generated
if (typeBldr != null) {
this.module = new XmlILModule(typeBldr);
} else {
this.module = new XmlILModule(useLRE, emitSymbols);
}
// Create a code generation helper for the module; enable optimizations if IsDebug is false
this.helper = new GenerateHelper(this.module, this.qil.IsDebug);
// Create helper methods
CreateHelperFunctions();
// Create metadata for the Execute function, which is the entry point to the query
// public static void Execute(XmlQueryRuntime);
MethodInfo methExec = this.module.DefineMethod("Execute", typeof(void), new Type[] { }, new string[] { }, XmlILMethodAttributes.NonUser);
// Create metadata for the root expression
// public void Root()
Debug.Assert(this.qil.Root != null);
XmlILMethodAttributes methAttrs = (this.qil.Root.SourceLine == null) ? XmlILMethodAttributes.NonUser : XmlILMethodAttributes.None;
MethodInfo methRoot = this.module.DefineMethod("Root", typeof(void), new Type[] { }, new string[] { }, methAttrs);
// Declare all early bound function objects
foreach (EarlyBoundInfo info in this.qil.EarlyBoundTypes) {
this.helper.StaticData.DeclareEarlyBound(info.NamespaceUri, info.EarlyBoundType);
}
// Create metadata for each QilExpression function that has at least one caller
CreateFunctionMetadata(this.qil.FunctionList);
// Create metadata for each QilExpression global variable and parameter
CreateGlobalValueMetadata(this.qil.GlobalVariableList);
CreateGlobalValueMetadata(this.qil.GlobalParameterList);
// Generate Execute method
GenerateExecuteFunction(methExec, methRoot);
// Visit the QilExpression graph
this.xmlIlVisitor = new XmlILVisitor();
this.xmlIlVisitor.Visit(this.qil, this.helper, methRoot);
// Collect all static information required by the runtime
XmlQueryStaticData staticData = new XmlQueryStaticData(
this.qil.DefaultWriterSettings,
this.qil.WhitespaceRules,
this.helper.StaticData
);
// Create static constructor that initializes XmlQueryStaticData instance at runtime
if (typeBldr != null) {
CreateTypeInitializer(staticData);
// Finish up creation of the type
this.module.BakeMethods();
return null;
} else {
// Finish up creation of the type
this.module.BakeMethods();
// Create delegate over "Execute" method
ExecuteDelegate delExec = (ExecuteDelegate)this.module.CreateDelegate("Execute", typeof(ExecuteDelegate));
return new XmlILCommand(delExec, staticData);
}
}
/// <summary>
/// Create MethodBuilder metadata for the specified QilExpression function. Annotate ndFunc with the
/// MethodBuilder. Also, each QilExpression argument type should be converted to a corresponding Clr type.
/// Each argument QilExpression node should be annotated with the resulting ParameterBuilder.
/// </summary>
private void CreateFunctionMetadata(IList<QilNode> funcList) {
MethodInfo methInfo;
Type[] paramTypes;
string[] paramNames;
Type typReturn;
XmlILMethodAttributes methAttrs;
foreach (QilFunction ndFunc in funcList) {
paramTypes = new Type[ndFunc.Arguments.Count];
paramNames = new string[ndFunc.Arguments.Count];
// Loop through all other parameters and save their types in the array
for (int arg = 0; arg < ndFunc.Arguments.Count; arg ++) {
QilParameter ndParam = (QilParameter) ndFunc.Arguments[arg];
Debug.Assert(ndParam.NodeType == QilNodeType.Parameter);
// Get the type of each argument as a Clr type
paramTypes[arg] = XmlILTypeHelper.GetStorageType(ndParam.XmlType);
// Get the name of each argument
if (ndParam.DebugName != null)
paramNames[arg] = ndParam.DebugName;
}
// Get the type of the return value
if (XmlILConstructInfo.Read(ndFunc).PushToWriterLast) {
// Push mode functions do not have a return value
typReturn = typeof(void);
}
else {
// Pull mode functions have a return value
typReturn = XmlILTypeHelper.GetStorageType(ndFunc.XmlType);
}
// Create the method metadata
methAttrs = ndFunc.SourceLine == null ? XmlILMethodAttributes.NonUser : XmlILMethodAttributes.None;
methInfo = this.module.DefineMethod(ndFunc.DebugName, typReturn, paramTypes, paramNames, methAttrs);
for (int arg = 0; arg < ndFunc.Arguments.Count; arg ++) {
// Set location of parameter on Let node annotation
XmlILAnnotation.Write(ndFunc.Arguments[arg]).ArgumentPosition = arg;
}
// Annotate function with the MethodInfo
XmlILAnnotation.Write(ndFunc).FunctionBinding = methInfo;
}
}
/// <summary>
/// Generate metadata for a method that calculates a global value.
/// </summary>
private void CreateGlobalValueMetadata(IList<QilNode> globalList) {
MethodInfo methInfo;
Type typReturn;
XmlILMethodAttributes methAttrs;
foreach (QilReference ndRef in globalList) {
// public T GlobalValue()
typReturn = XmlILTypeHelper.GetStorageType(ndRef.XmlType);
methAttrs = ndRef.SourceLine == null ? XmlILMethodAttributes.NonUser : XmlILMethodAttributes.None;
methInfo = this.module.DefineMethod(ndRef.DebugName.ToString(), typReturn, new Type[] {}, new string[] {}, methAttrs);
// Annotate function with MethodBuilder
XmlILAnnotation.Write(ndRef).FunctionBinding = methInfo;
}
}
/// <summary>
/// Generate the "Execute" method, which is the entry point to the query.
/// </summary>
private MethodInfo GenerateExecuteFunction(MethodInfo methExec, MethodInfo methRoot) {
this.helper.MethodBegin(methExec, null, false);
// Force some or all global values to be evaluated at start of query
EvaluateGlobalValues(this.qil.GlobalVariableList);
EvaluateGlobalValues(this.qil.GlobalParameterList);
// Root(runtime);
this.helper.LoadQueryRuntime();
this.helper.Call(methRoot);
this.helper.MethodEnd();
return methExec;
}
/// <summary>
/// Create and generate various helper methods, which are called by the generated code.
/// </summary>
private void CreateHelperFunctions() {
MethodInfo meth;
Label lblClone;
// public static XPathNavigator SyncToNavigator(XPathNavigator, XPathNavigator);
meth = this.module.DefineMethod(
"SyncToNavigator",
typeof(XPathNavigator),
new Type[] {typeof(XPathNavigator), typeof(XPathNavigator)},
new string[] {null, null},
XmlILMethodAttributes.NonUser | XmlILMethodAttributes.Raw);
this.helper.MethodBegin(meth, null, false);
// if (navigatorThis != null && navigatorThis.MoveTo(navigatorThat))
// return navigatorThis;
lblClone = this.helper.DefineLabel();
this.helper.Emit(OpCodes.Ldarg_0);
this.helper.Emit(OpCodes.Brfalse, lblClone);
this.helper.Emit(OpCodes.Ldarg_0);
this.helper.Emit(OpCodes.Ldarg_1);
this.helper.Call(XmlILMethods.NavMoveTo);
this.helper.Emit(OpCodes.Brfalse, lblClone);
this.helper.Emit(OpCodes.Ldarg_0);
this.helper.Emit(OpCodes.Ret);
// LabelClone:
// return navigatorThat.Clone();
this.helper.MarkLabel(lblClone);
this.helper.Emit(OpCodes.Ldarg_1);
this.helper.Call(XmlILMethods.NavClone);
this.helper.MethodEnd();
}
/// <summary>
/// Generate code to force evaluation of some or all global variables and/or parameters.
/// </summary>
private void EvaluateGlobalValues(IList<QilNode> iterList) {
MethodInfo methInfo;
foreach (QilIterator ndIter in iterList) {
// Evaluate global if generating debug code, or if global might have side effects
if (this.qil.IsDebug || OptimizerPatterns.Read(ndIter).MatchesPattern(OptimizerPatternName.MaybeSideEffects)) {
// Get MethodInfo that evaluates the global value and discard its return value
methInfo = XmlILAnnotation.Write(ndIter).FunctionBinding;
Debug.Assert(methInfo != null, "MethodInfo for global value should have been created previously.");
this.helper.LoadQueryRuntime();
this.helper.Call(methInfo);
this.helper.Emit(OpCodes.Pop);
}
}
}
/// <summary>
/// Create static constructor that initializes XmlQueryStaticData instance at runtime.
/// </summary>
public void CreateTypeInitializer(XmlQueryStaticData staticData) {
byte[] data;
Type[] ebTypes;
FieldInfo fldInitData, fldData, fldTypes;
ConstructorInfo cctor;
staticData.GetObjectData(out data, out ebTypes);
fldInitData = this.module.DefineInitializedData("__" + XmlQueryStaticData.DataFieldName, data);
fldData = this.module.DefineField(XmlQueryStaticData.DataFieldName, typeof(object));
fldTypes = this.module.DefineField(XmlQueryStaticData.TypesFieldName, typeof(Type[]));
cctor = this.module.DefineTypeInitializer();
this.helper.MethodBegin(cctor, null, false);
// s_data = new byte[s_initData.Length] { s_initData };
this.helper.LoadInteger(data.Length);
this.helper.Emit(OpCodes.Newarr, typeof(byte));
this.helper.Emit(OpCodes.Dup);
this.helper.Emit(OpCodes.Ldtoken, fldInitData);
this.helper.Call(XmlILMethods.InitializeArray);
this.helper.Emit(OpCodes.Stsfld, fldData);
if (ebTypes != null) {
// Type[] types = new Type[s_ebTypes.Length];
LocalBuilder locTypes = this.helper.DeclareLocal("$$$types", typeof(Type[]));
this.helper.LoadInteger(ebTypes.Length);
this.helper.Emit(OpCodes.Newarr, typeof(Type));
this.helper.Emit(OpCodes.Stloc, locTypes);
for (int idx = 0; idx < ebTypes.Length; idx++) {
// types[idx] = ebTypes[idx];
this.helper.Emit(OpCodes.Ldloc, locTypes);
this.helper.LoadInteger(idx);
this.helper.LoadType(ebTypes[idx]);
this.helper.Emit(OpCodes.Stelem_Ref);
}
// s_types = types;
this.helper.Emit(OpCodes.Ldloc, locTypes);
this.helper.Emit(OpCodes.Stsfld, fldTypes);
}
this.helper.MethodEnd();
}
}
}
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