Adding Support for FieldDescSlot generic dictionary entries for R2R generic code. (#6200)

This enables generic code with ldtoken instructions for fields on generic types to be compiled into R2R.

This change makes newer versions of the runtime compatible with older version R2R images,
but not vice-versa. Therefore, the major version is increased to 2 with this change.

This change adds more encodings to a R2R image without changing the format of any previously encoded
entity, and is backwards compatible.

1 files changed, 34 insertions, 14 deletions

diff --git a/src/vm/zapsig.cpp b/src/vm/zapsig.cpp
index 93b34db31e..c619610f42 100644
--- a/src/vm/zapsig.cpp
+++ b/src/vm/zapsig.cpp
@@ -836,7 +836,7 @@ MethodDesc *ZapSig::DecodeMethod(Module *pReferencingModule,
                                  Module *pInfoModule,
                                  PCCOR_SIGNATURE pBuffer,
                                  SigTypeContext *pContext,
-                                 TypeHandle * ppTH, /*=NULL*/
+                                 TypeHandle *ppTH, /*=NULL*/
                                  PCCOR_SIGNATURE *ppOwnerTypeSpecWithVars, /*=NULL*/
                                  PCCOR_SIGNATURE *ppMethodSpecWithVars /*=NULL*/)
 {
@@ -1013,7 +1013,20 @@ MethodDesc *ZapSig::DecodeMethod(Module *pReferencingModule,
 FieldDesc * ZapSig::DecodeField(Module *pReferencingModule,
                                 Module *pInfoModule,
                                 PCCOR_SIGNATURE pBuffer,
-                                TypeHandle * ppTH /*=NULL*/)
+                                TypeHandle *ppTH /*=NULL*/)
+{
+    STANDARD_VM_CONTRACT;
+
+    SigTypeContext typeContext;    // empty context is OK: encoding should not contain type variables.
+
+    return DecodeField(pReferencingModule, pInfoModule, pBuffer, &typeContext, ppTH);
+}
+
+FieldDesc * ZapSig::DecodeField(Module *pReferencingModule,
+                                Module *pInfoModule,
+                                PCCOR_SIGNATURE pBuffer,
+                                SigTypeContext *pContext,
+                                TypeHandle *ppTH /*=NULL*/)
 {
     CONTRACTL
     {
@@ -1037,10 +1050,8 @@ FieldDesc * ZapSig::DecodeField(Module *pReferencingModule,
         ZapSig::Context    zapSigContext(pInfoModule, pReferencingModule);
         ZapSig::Context *  pZapSigContext = &zapSigContext;
 
-        SigTypeContext typeContext;    // empty context is OK: encoding should not contain type variables.
-
         pOwnerMT = sig.GetTypeHandleThrowing(pInfoModule,
-                                        &typeContext,
+                                        pContext,
                                         ClassLoader::LoadTypes,
                                         CLASS_LOADED,
                                         FALSE,
@@ -1371,7 +1382,8 @@ void ZapSig::EncodeField(
         SigBuilder             *pSigBuilder,
         LPVOID                 pEncodeModuleContext,
         ENCODEMODULE_CALLBACK  pfnEncodeModule,
-        CORINFO_RESOLVED_TOKEN * pResolvedToken)
+        CORINFO_RESOLVED_TOKEN *pResolvedToken,
+        BOOL                   fEncodeUsingResolvedTokenSpecStreams)
 {
     CONTRACTL
     {
@@ -1452,15 +1464,23 @@ void ZapSig::EncodeField(
 
     if (fieldFlags & ENCODE_FIELD_SIG_OwnerType)
     {
-        ZapSig zapSig(pInfoModule, pEncodeModuleContext, ZapSig::NormalTokens,
-                        (EncodeModuleCallback) pfnEncodeModule, NULL);
+        if (fEncodeUsingResolvedTokenSpecStreams && pResolvedToken != NULL && pResolvedToken->pTypeSpec != NULL)
+        {
+            _ASSERTE(pResolvedToken->cbTypeSpec > 0);
+            pSigBuilder->AppendBlob((PVOID)pResolvedToken->pTypeSpec, pResolvedToken->cbTypeSpec);
+        }
+        else
+        {
+            ZapSig zapSig(pInfoModule, pEncodeModuleContext, ZapSig::NormalTokens,
+                (EncodeModuleCallback)pfnEncodeModule, NULL);
 
-        //
-        // Write class
-        //
-        BOOL fSuccess;
-        fSuccess = zapSig.GetSignatureForTypeHandle(pMT, pSigBuilder);
-        _ASSERTE(fSuccess);
+            //
+            // Write class
+            //
+            BOOL fSuccess;
+            fSuccess = zapSig.GetSignatureForTypeHandle(pMT, pSigBuilder);
+            _ASSERTE(fSuccess);
+        }
     }
 
     if ((fieldFlags & ENCODE_FIELD_SIG_IndexInsteadOfToken) == 0)