Remove AggressiveOptimization flag from System.Text (#25356)

Based on conversation with Levi, I don't think this flag is needed.

The flag currently controls two things:
* Disqualifies the method from precompilation
* Disables Tier-0 JIT for the method

Removing the attribute allows us to precompile some of the methods (not all, because of `Vector<T>`). It measurably helps improve startup time because many of the attributed methods are complex and take a while to compile.

Once tier-1 JIT kicks in, the generated code should be identical to what we were getting before.

diff --git a/src/System.Private.CoreLib/shared/System/Text/ASCIIUtility.cs b/src/System.Private.CoreLib/shared/System/Text/ASCIIUtility.cs
index 4f7f996..b37b017 100644 (file)
--- a/src/System.Private.CoreLib/shared/System/Text/ASCIIUtility.cs
+++ b/src/System.Private.CoreLib/shared/System/Text/ASCIIUtility.cs
@@ -228,7 +228,6 @@ namespace System.Text
             goto Finish;
         }
 
-        [MethodImpl(MethodImplOptions.AggressiveOptimization)]
         private static unsafe nuint GetIndexOfFirstNonAsciiByte_Sse2(byte* pBuffer, nuint bufferLength)
         {
             // JIT turns the below into constants
@@ -642,7 +641,6 @@ namespace System.Text
             goto Finish;
         }
 
-        [MethodImpl(MethodImplOptions.AggressiveOptimization)]
         private static unsafe nuint GetIndexOfFirstNonAsciiChar_Sse2(char* pBuffer, nuint bufferLength /* in chars */)
         {
             // This method contains logic optimized for both SSE2 and SSE41. Much of the logic in this method
@@ -1006,7 +1004,7 @@ namespace System.Text
         /// narrows each WORD to a BYTE, then writes the 4-byte result to the output buffer
         /// also in machine-endian order.
         /// </summary>
-        [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private static void NarrowFourUtf16CharsToAsciiAndWriteToBuffer(ref byte outputBuffer, ulong value)
         {
             Debug.Assert(AllCharsInUInt64AreAscii(value));
@@ -1046,7 +1044,7 @@ namespace System.Text
         /// narrows each WORD to a BYTE, then writes the 2-byte result to the output buffer also in
         /// machine-endian order.
         /// </summary>
-        [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private static void NarrowTwoUtf16CharsToAsciiAndWriteToBuffer(ref byte outputBuffer, uint value)
         {
             Debug.Assert(AllCharsInUInt32AreAscii(value));
@@ -1069,7 +1067,6 @@ namespace System.Text
         /// or once <paramref name="elementCount"/> elements have been converted. Returns the total number
         /// of elements that were able to be converted.
         /// </summary>
-        [MethodImpl(MethodImplOptions.AggressiveOptimization)]
         public static unsafe nuint NarrowUtf16ToAscii(char* pUtf16Buffer, byte* pAsciiBuffer, nuint elementCount)
         {
             nuint currentOffset = 0;
@@ -1298,7 +1295,6 @@ namespace System.Text
             goto Finish;
         }
 
-        [MethodImpl(MethodImplOptions.AggressiveOptimization)]
         private static unsafe nuint NarrowUtf16ToAscii_Sse2(char* pUtf16Buffer, byte* pAsciiBuffer, nuint elementCount)
         {
             // This method contains logic optimized for both SSE2 and SSE41. Much of the logic in this method
@@ -1601,7 +1597,6 @@ namespace System.Text
             goto Finish;
         }
 
-        [MethodImpl(MethodImplOptions.AggressiveOptimization)]
         private static unsafe nuint WidenAsciiToUtf16_Sse2(byte* pAsciiBuffer, char* pUtf16Buffer, nuint elementCount)
         {
             // JIT turns the below into constants
@@ -1698,7 +1693,7 @@ namespace System.Text
         /// Given a DWORD which represents a buffer of 4 bytes, widens the buffer into 4 WORDs and
         /// writes them to the output buffer with machine endianness.
         /// </summary>
-        [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private static void WidenFourAsciiBytesToUtf16AndWriteToBuffer(ref char outputBuffer, uint value)
         {
             Debug.Assert(AllBytesInUInt32AreAscii(value));

diff --git a/src/System.Private.CoreLib/shared/System/Text/Unicode/Utf8Utility.Helpers.cs b/src/System.Private.CoreLib/shared/System/Text/Unicode/Utf8Utility.Helpers.cs
index ab29fbe..54940f9 100644 (file)
--- a/src/System.Private.CoreLib/shared/System/Text/Unicode/Utf8Utility.Helpers.cs
+++ b/src/System.Private.CoreLib/shared/System/Text/Unicode/Utf8Utility.Helpers.cs
@@ -64,7 +64,7 @@ namespace System.Text.Unicode
         /// Given a machine-endian DWORD which four bytes of UTF-8 data, interprets the input as a
         /// four-byte UTF-8 sequence and returns the machine-endian DWORD of the UTF-16 representation.
         /// </summary>
-        [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private static uint ExtractCharsFromFourByteSequence(uint value)
         {
             if (BitConverter.IsLittleEndian)
@@ -760,7 +760,7 @@ namespace System.Text.Unicode
         /// Given a DWORD which represents a buffer of 4 ASCII bytes, widen each byte to a 16-bit WORD
         /// and writes the resulting QWORD into the destination with machine endianness.
         /// </summary>
-        [MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private static void Widen4AsciiBytesToCharsAndWrite(ref char outputBuffer, uint value)
         {
             if (Bmi2.X64.IsSupported)

diff --git a/src/System.Private.CoreLib/shared/System/Text/Unicode/Utf8Utility.Transcoding.cs b/src/System.Private.CoreLib/shared/System/Text/Unicode/Utf8Utility.Transcoding.cs
index 3b83a24..126974c 100644 (file)
--- a/src/System.Private.CoreLib/shared/System/Text/Unicode/Utf8Utility.Transcoding.cs
+++ b/src/System.Private.CoreLib/shared/System/Text/Unicode/Utf8Utility.Transcoding.cs
@@ -35,7 +35,6 @@ namespace System.Text.Unicode
         // On method return, pInputBufferRemaining and pOutputBufferRemaining will both point to where
         // the next byte would have been consumed from / the next char would have been written to.
         // inputLength in bytes, outputCharsRemaining in chars.
-        [MethodImpl(MethodImplOptions.AggressiveOptimization)]
         public static OperationStatus TranscodeToUtf16(byte* pInputBuffer, int inputLength, char* pOutputBuffer, int outputCharsRemaining, out byte* pInputBufferRemaining, out char* pOutputBufferRemaining)
         {
             Debug.Assert(inputLength >= 0, "Input length must not be negative.");