Add MethodImplOptions.AggressiveOptimization and use it for tiering (#20009)

Add MethodImplOptions.AggressiveOptimization and use it for tiering

Part of fix for https://github.com/dotnet/corefx/issues/32235
Workaround for https://github.com/dotnet/coreclr/issues/19751
- Added and set CORJIT_FLAG_AGGRESSIVE_OPT to indicate that a method is flagged with AggressiveOptimization
- For a method flagged with AggressiveOptimization, tiering uses a foreground tier 1 JIT on first call to the method, skipping the tier 0 JIT and call counting
- When tiering is disabled, a method flagged with AggressiveOptimization does not use r2r-pregenerated code
- R2r crossgen does not generate code for a method flagged with AggressiveOptimization

1 files changed, 9 insertions, 1 deletions

diff --git a/src/zap/zapinfo.cpp b/src/zap/zapinfo.cpp
index 7320729dec..341e0d82af 100644
--- a/src/zap/zapinfo.cpp
+++ b/src/zap/zapinfo.cpp
@@ -435,6 +435,15 @@ void ZapInfo::CompileMethod()
     // this they can add the hint and reduce the perf cost at runtime.
     m_pImage->m_pPreloader->PrePrepareMethodIfNecessary(m_currentMethodHandle);
 
+    DWORD methodAttribs = getMethodAttribs(m_currentMethodHandle);
+    if (methodAttribs & CORINFO_FLG_AGGRESSIVE_OPT)
+    {
+        // Skip methods marked with MethodImplOptions.AggressiveOptimization, they will be jitted instead. In the future,
+        // consider letting the JIT determine whether aggressively optimized code can/should be pregenerated for the method
+        // instead of this check.
+        return;
+    }
+
     m_jitFlags = ComputeJitFlags(m_currentMethodHandle);
 
 #ifdef FEATURE_READYTORUN_COMPILER
@@ -443,7 +452,6 @@ void ZapInfo::CompileMethod()
         // READYTORUN: FUTURE: Producedure spliting
         m_jitFlags.Clear(CORJIT_FLAGS::CORJIT_FLAG_PROCSPLIT);
 
-        DWORD methodAttribs = getMethodAttribs(m_currentMethodHandle);
         if (!(methodAttribs & CORINFO_FLG_NOSECURITYWRAP) || (methodAttribs & CORINFO_FLG_SECURITYCHECK))
         {
             m_zapper->Warning(W("ReadyToRun: Methods with security checks not supported\n"));