Skip to content

Commit

Permalink
Use vectorized IndeOf for some notoneloopgreedy loops
Browse files Browse the repository at this point in the history
  • Loading branch information
@stephentoub
stephentoub committed Jan 9, 2020
1 parent 807fcc3 commit 8ed69c9
Showing 1 changed file with 93 additions and 58 deletions.
151 changes: 93 additions & 58 deletions ...raries/System.Text.RegularExpressions/src/System/Text/RegularExpressions/RegexCompiler.cs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -51,6 +51,7 @@ internal abstract class RegexCompiler
private static readonly MethodInfo s_stringGetCharsMethod = typeof(string).GetMethod("get_Chars", new Type[] { typeof(int) })!;
private static readonly MethodInfo s_stringAsSpanMethod = typeof(MemoryExtensions).GetMethod("AsSpan", new Type[] { typeof(string), typeof(int), typeof(int) })!;
private static readonly MethodInfo s_stringIndexOf = typeof(string).GetMethod("IndexOf", new Type[] { typeof(char), typeof(int), typeof(int) })!;
private static readonly MethodInfo s_spanIndexOf = typeof(MemoryExtensions).GetMethod("IndexOf", new Type[] { typeof(ReadOnlySpan<>).MakeGenericType(Type.MakeGenericMethodParameter(0)), Type.MakeGenericMethodParameter(0) })!.MakeGenericMethod(typeof(char));
private static readonly MethodInfo s_spanIndexOfAnyCharChar = typeof(MemoryExtensions).GetMethod("IndexOfAny", new Type[] { typeof(ReadOnlySpan<>).MakeGenericType(Type.MakeGenericMethodParameter(0)), Type.MakeGenericMethodParameter(0), Type.MakeGenericMethodParameter(0) })!.MakeGenericMethod(typeof(char));
private static readonly MethodInfo s_spanIndexOfAnyCharCharChar = typeof(MemoryExtensions).GetMethod("IndexOfAny", new Type[] { typeof(ReadOnlySpan<>).MakeGenericType(Type.MakeGenericMethodParameter(0)), Type.MakeGenericMethodParameter(0), Type.MakeGenericMethodParameter(0), Type.MakeGenericMethodParameter(0) })!.MakeGenericMethod(typeof(char));
private static readonly MethodInfo s_spanGetItemMethod = typeof(ReadOnlySpan<char>).GetMethod("get_Item", new Type[] { typeof(int) })!;
Expand Down Expand Up @@ -1901,6 +1902,8 @@ void EmitGreedyLoop(RegexNode node)
Debug.Assert(node.Type == RegexNode.Oneloopgreedy || node.Type == RegexNode.Notoneloopgreedy || node.Type == RegexNode.Setloopgreedy);
Debug.Assert(node.M < int.MaxValue);

iterationLocal ??= DeclareInt32();

// First generate the code to handle the required number of iterations.
if (node.M > 0)
{
Expand All @@ -1910,73 +1913,105 @@ void EmitGreedyLoop(RegexNode node)
// Then generate the code to handle the 0 or more remaining optional iterations.
if (node.N > node.M)
{
Label conditionLabel = DefineLabel();
Label bodyLabel = DefineLabel();
Label originalDoneLabel = doneLabel;
iterationLocal ??= DeclareInt32();

doneLabel = DefineLabel();
int maxIterations = node.N == int.MaxValue ? int.MaxValue : node.N - node.M;

// int i = 0;
Ldc(0);
Stloc(iterationLocal);
BrFar(conditionLabel);

// Body:
// TimeoutCheck();
// if (!match) goto Done;
MarkLabel(bodyLabel);
EmitTimeoutCheck();

// if (textSpan[textSpanPos + i] != ch) goto Done;
Ldloca(textSpanLocal);
Ldc(textSpanPos);
Ldloc(iterationLocal);
Add();
Call(s_spanGetItemMethod);
LdindU2();
switch (node.Type)
if (node.Type == RegexNode.Notoneloopgreedy && node.N == int.MaxValue && !IsCaseInsensitive(node))
{
case RegexNode.Oneloopgreedy:
if (IsCaseInsensitive(node)) CallToLower();
Ldc(node.Ch);
BneFar(doneLabel);
break;
case RegexNode.Notoneloopgreedy:
if (IsCaseInsensitive(node)) CallToLower();
Ldc(node.Ch);
BeqFar(doneLabel);
break;
case RegexNode.Setloopgreedy:
EmitCallCharInClass(node.Str!, IsCaseInsensitive(node), setScratchLocal);
BrfalseFar(doneLabel);
break;
}

// i++;
Ldloc(iterationLocal);
Ldc(1);
Add();
Stloc(iterationLocal);
// For Notoneloopgreedy, we're looking for a specific character, as everything until we find
// it is consumed by the loop. If we're unbounded, such as with ".*" and if we're case-sensitive,
// we can use the vectorized IndexOf to do the search, rather than open-coding it. (In the future,
// we could consider using IndexOf with StringComparison for case insensitivity.)

// int i = textSpan.Slice(textSpanPos).IndexOf(char);
Ldloca(textSpanLocal);
Ldc(textSpanPos);
Call(s_spanSliceMethod);
Ldc(node.Ch);
Call(s_spanIndexOf);
Stloc(iterationLocal);

// if ((uint)(textSpanPos + i) >= (uint)textSpan.Length || i >= maxIterations) goto Done;
MarkLabel(conditionLabel);
Ldc(textSpanPos);
Ldloc(iterationLocal);
Add();
Ldloca(textSpanLocal);
Call(s_spanGetLengthMethod);
BgeUnFar(doneLabel);
if (maxIterations != int.MaxValue)
{
// if (i != -1) goto doneLabel;
Ldloc(iterationLocal);
Ldc(maxIterations);
BltFar(bodyLabel);
Ldc(-1);
BneFar(doneLabel);

// i = textSpan.Length - textSpanPos;
Ldloca(textSpanLocal);
Call(s_spanGetLengthMethod);
Ldc(textSpanPos);
Sub();
Stloc(iterationLocal);
}
else
{
BrFar(bodyLabel);
// For everything else, do a normal loop.

Label conditionLabel = DefineLabel();
Label bodyLabel = DefineLabel();

int maxIterations = node.N == int.MaxValue ? int.MaxValue : node.N - node.M;

// int i = 0;
Ldc(0);
Stloc(iterationLocal);
BrFar(conditionLabel);

// Body:
// TimeoutCheck();
// if (!match) goto Done;
MarkLabel(bodyLabel);
EmitTimeoutCheck();

// if (textSpan[textSpanPos + i] != ch) goto Done;
Ldloca(textSpanLocal);
Ldc(textSpanPos);
Ldloc(iterationLocal);
Add();
Call(s_spanGetItemMethod);
LdindU2();
switch (node.Type)
{
case RegexNode.Oneloopgreedy:
if (IsCaseInsensitive(node)) CallToLower();
Ldc(node.Ch);
BneFar(doneLabel);
break;
case RegexNode.Notoneloopgreedy:
if (IsCaseInsensitive(node)) CallToLower();
Ldc(node.Ch);
BeqFar(doneLabel);
break;
case RegexNode.Setloopgreedy:
EmitCallCharInClass(node.Str!, IsCaseInsensitive(node), setScratchLocal);
BrfalseFar(doneLabel);
break;
}

// i++;
Ldloc(iterationLocal);
Ldc(1);
Add();
Stloc(iterationLocal);

// if ((uint)(textSpanPos + i) >= (uint)textSpan.Length || i >= maxIterations) goto Done;
MarkLabel(conditionLabel);
Ldc(textSpanPos);
Ldloc(iterationLocal);
Add();
Ldloca(textSpanLocal);
Call(s_spanGetLengthMethod);
BgeUnFar(doneLabel);
if (maxIterations != int.MaxValue)
{
Ldloc(iterationLocal);
Ldc(maxIterations);
BltFar(bodyLabel);
}
else
{
BrFar(bodyLabel);
}
}

// Done:
Expand Down

0 comments on commit 8ed69c9

Please sign in to comment.