Initial implementation of generic dictionary access for R2R. (#4519)

For now, only TypeHandle dictionary entry slots are supported and encoded in a R2R version resilient format (the rest to come soon).
Support is only limited for x64 Windows platforms (rest is still TODO)

The basic idea: each dictionary access is initally a call to a DynamicHelper R2R cell that computes the dictionary signature, and patches the R2R cell address with an assembly stub that performs the dictionary lookup.

1 files changed, 65 insertions, 4 deletions

diff --git a/src/zap/zapimport.cpp b/src/zap/zapimport.cpp
index c0ea82743a..37226fcc41 100644
--- a/src/zap/zapimport.cpp
+++ b/src/zap/zapimport.cpp
@@ -1697,7 +1697,22 @@ public:
 
     CORCOMPILE_FIXUP_BLOB_KIND GetKind()
     {
-        return (CORCOMPILE_FIXUP_BLOB_KIND)(int)GetHandle();
+        int kind = (int)GetHandle();
+
+        if ((kind & 1) == 1)
+        {
+            return (CORCOMPILE_FIXUP_BLOB_KIND)(kind >> 1);
+        }
+        else
+        {
+            _ASSERTE(
+                (GetBlob()->GetSize() > 0) && (
+                    GetBlob()->GetData()[0] == ENCODE_DICTIONARY_LOOKUP_THISOBJ ||
+                    GetBlob()->GetData()[0] == ENCODE_DICTIONARY_LOOKUP_METHOD ||
+                    GetBlob()->GetData()[0] == ENCODE_DICTIONARY_LOOKUP_TYPE));
+
+            return (CORCOMPILE_FIXUP_BLOB_KIND)GetBlob()->GetData()[0];
+        }
     }
 
     virtual void EncodeSignature(ZapImportTable * pTable, SigBuilder * pSigBuilder)
@@ -1728,6 +1743,9 @@ static ReadyToRunHelper GetDelayLoadHelperForDynamicHelper(CORCOMPILE_FIXUP_BLOB
     case ENCODE_THREAD_STATIC_BASE_GC_HELPER:
     case ENCODE_CCTOR_TRIGGER:
     case ENCODE_FIELD_ADDRESS:
+    case ENCODE_DICTIONARY_LOOKUP_THISOBJ:
+    case ENCODE_DICTIONARY_LOOKUP_TYPE:
+    case ENCODE_DICTIONARY_LOOKUP_METHOD:
         return READYTORUN_HELPER_DelayLoad_Helper;
 
     case ENCODE_CHKCAST_HELPER:
@@ -1773,9 +1791,52 @@ void ZapImportSectionSignatures::PlaceDynamicHelperCell(ZapImport * pImport)
     m_pImage->GetImportTable()->PlaceImportBlob(pCell);
 }
 
+ZapImport * ZapImportTable::GetDictionaryLookupCell(CORCOMPILE_FIXUP_BLOB_KIND kind, CORINFO_RESOLVED_TOKEN * pResolvedToken, CORINFO_LOOKUP_KIND * pLookup)
+{
+    _ASSERTE(pLookup->needsRuntimeLookup);
+
+    SigBuilder sigBuilder;
+
+    sigBuilder.AppendData(kind & ~CORINFO_HELP_READYTORUN_ATYPICAL_CALLSITE);
+
+    if ((kind & ~CORINFO_HELP_READYTORUN_ATYPICAL_CALLSITE) == ENCODE_DICTIONARY_LOOKUP_THISOBJ)
+    {
+        CORINFO_CLASS_HANDLE hClassContext = GetJitInfo()->getMethodClass(pResolvedToken->tokenContext);
+        GetCompileInfo()->EncodeClass(m_pImage->GetModuleHandle(), hClassContext, &sigBuilder, NULL, NULL);
+    }
+
+    switch (pLookup->runtimeLookupFlags)
+    {
+    case READYTORUN_FIXUP_TypeHandle:
+        {
+            if (pResolvedToken->pTypeSpec == NULL)
+            {
+                _ASSERTE(!"Invalid IL that directly references __Canon");
+                ThrowHR(E_NOTIMPL);
+            }
+
+            sigBuilder.AppendData(ENCODE_TYPE_HANDLE);
+            if (pResolvedToken->tokenType == CORINFO_TOKENKIND_Newarr)
+                sigBuilder.AppendElementType(ELEMENT_TYPE_SZARRAY);
+            sigBuilder.AppendBlob((PVOID)pResolvedToken->pTypeSpec, pResolvedToken->cbTypeSpec);
+        }
+        break;
+
+    // TODO: support for the rest of the dictionary signature kinds
+
+    default:
+        _ASSERTE(!"Invalid R2R fixup kind!");
+        ThrowHR(E_NOTIMPL);
+    }
+
+    _ASSERTE(((DWORD)pResolvedToken->tokenContext & 1) == 0);
+
+    return GetImportForSignature<ZapDynamicHelperCell, ZapNodeType_DynamicHelperCell>((void*)pResolvedToken->tokenContext, &sigBuilder);
+}
+
 ZapImport * ZapImportTable::GetDynamicHelperCell(CORCOMPILE_FIXUP_BLOB_KIND kind, CORINFO_CLASS_HANDLE handle)
 {
-    ZapImport * pImport = GetImport<ZapDynamicHelperCell, ZapNodeType_DynamicHelperCell>((void *)kind, handle);
+    ZapImport * pImport = GetImport<ZapDynamicHelperCell, ZapNodeType_DynamicHelperCell>((void *)(uintptr_t)((kind << 1) | 1), handle);
 
     if (!pImport->HasBlob())
     {
@@ -1805,7 +1866,7 @@ ZapImport * ZapImportTable::GetDynamicHelperCell(CORCOMPILE_FIXUP_BLOB_KIND kind
         GetCompileInfo()->EncodeClass(m_pImage->GetModuleHandle(), delegateType, &sigBuilder, NULL, NULL);
     }
 
-    return GetImportForSignature<ZapDynamicHelperCell, ZapNodeType_DynamicHelperCell>((void *)kind, &sigBuilder);
+    return GetImportForSignature<ZapDynamicHelperCell, ZapNodeType_DynamicHelperCell>((void *)(uintptr_t)((kind << 1) | 1), &sigBuilder);
 }
 
 ZapImport * ZapImportTable::GetDynamicHelperCell(CORCOMPILE_FIXUP_BLOB_KIND kind, CORINFO_FIELD_HANDLE handle, CORINFO_RESOLVED_TOKEN * pResolvedToken)
@@ -1815,7 +1876,7 @@ ZapImport * ZapImportTable::GetDynamicHelperCell(CORCOMPILE_FIXUP_BLOB_KIND kind
     EncodeField((CORCOMPILE_FIXUP_BLOB_KIND)(kind & ~CORINFO_HELP_READYTORUN_ATYPICAL_CALLSITE),
         handle, &sigBuilder, pResolvedToken);
 
-    return GetImportForSignature<ZapDynamicHelperCell, ZapNodeType_DynamicHelperCell>((void *)kind, &sigBuilder);
+    return GetImportForSignature<ZapDynamicHelperCell, ZapNodeType_DynamicHelperCell>((void *)(uintptr_t)((kind << 1) | 1), &sigBuilder);
 }
 
 class ZapIndirectHelperThunk : public ZapImport