| name | add-new-jit-ee-api |
| description | Add a new API to the JIT-VM (aka JIT-EE) interface in the codebase. |
JIT-EE Interface extension
1 — Goal
Implement one new JIT-VM (also known as JIT-EE) API and all supporting glue.
The JIT-VM interface defines the APIs through which the JIT compiler communicates with the runtime (VM).
2 — Required user inputs
Ask the user for a C-like signature of the new API if it's not provided.
Suggest <repo_root>/src/coreclr/tools/Common/JitInterface/ThunkGenerator/ThunkInput.txt file as a reference. Example:
CORINFO_METHOD_HANDLE getUnboxedEntry(CORINFO_METHOD_HANDLE ftn, bool* requiresInstMethodTableArg);
3 — Implementation steps (must be completed in order)
- Update the
ThunkInput.txt file with the new API definition. Example:
+CORINFO_METHOD_HANDLE getUnboxedEntry(CORINFO_METHOD_HANDLE ftn, bool* requiresInstMethodTableArg);
Insert the new API definition without removing any existing entries, placing it near similar signatures.
-
Invoke <repo_root>/src/coreclr/tools/Common/JitInterface/ThunkGenerator/gen.sh script
(or <repo_root>/src/coreclr/tools/Common/JitInterface/ThunkGenerator/gen.bat on Windows) to update auto-generated files.
Use the correct directory for the script to run.
-
Open <repo_root>/src/coreclr/inc/corinfo.h and add the new API inside class ICorStaticInfo class as the last member. Example:
+ virtual CORINFO_METHOD_HANDLE getUnboxedEntry(
+ CORINFO_METHOD_HANDLE ftn,
+ bool* requiresInstMethodTableArg
+ ) = 0;
- Open
<repo_root>/src/coreclr/tools/Common/JitInterface/CorInfoImpl.cs and add the new API in the end of class CorInfoImpl class declaration. Use <repo_root>/src/coreclr/tools/Common/JitInterface/CorInfoImpl_generated.cs to inspect how type parameters look like for C# for the newly added API since it is expected to be auto-generated there by the gen.sh(bat) script. Example:
+ private CORINFO_METHOD_STRUCT_* getUnboxedEntry(CORINFO_METHOD_STRUCT_* ftn, ref bool requiresInstMethodTableArg)
+ {
+ // Use CorInfoImpl.RyuJit.cs and CorInfoImpl.ReadyToRun.cs if the implementation
+ // is not shared for NativeAOT and R2R.
+ throw new NotImplementedException();
+ }
Implement the API if asked, leave the NotImplementedException() otherwise.
- Open
<repo_root>/src/coreclr/vm/jitinterface.cpp and add a dummy implementation at the file's end. Example:
+CORINFO_METHOD_HANDLE CEEInfo::getUnboxedEntry(
+ CORINFO_METHOD_HANDLE ftn,
+ bool* requiresInstMethodTableArg)
+{
+ CONTRACTL {
+ THROWS;
+ GC_TRIGGERS;
+ MODE_PREEMPTIVE;
+ } CONTRACTL_END;
+
+ CORINFO_METHOD_HANDLE result = NULL;
+
+ JIT_TO_EE_TRANSITION();
+
+ UNREACHABLE(); // To be implemented
+
+ EE_TO_JIT_TRANSITION();
+
+ return result;
+}
Implement the API if asked, leave the UNREACHABLE() otherwise.
- Now implement the most complex part - SuperPMI. SuperPMI acts as a (de)serializer for JIT-VM queries in order
to then replay them without the actual VM to speed up jit-diffs and other scenarios. All parameters and return
values recorded/restored using special primitve types and helpers. We need to update the following files:
<repo_root>/src/coreclr/tools/superpmi/superpmi-shared/agnostic.h:<repo_root>/src/coreclr/tools/superpmi/superpmi-shared/lwmlist.h:<repo_root>/src/coreclr/tools/superpmi/superpmi-shared/methodcontext.h:<repo_root>/src/coreclr/tools/superpmi/superpmi-shared/methodcontext.cpp:
Go through each of them one by one.
-
<repo_root>/src/coreclr/tools/superpmi/superpmi-shared/agnostic.h:
Define two Agnostic_* types for input arguments and another one for output parameters (return value, output arguments).
Do not create them if one of the generics ones can be re-used such as DLD, DD, DLDL, etc. Use DWORD*
like types for integers. Inspect the whole file to see how other APIs are defined.
-
<repo_root>/src/coreclr/tools/superpmi/superpmi-shared/lwmlist.h:
Add a new entry to the LWM list. Example:
+LWM(GetUnboxedEntry, DWORDLONG, DLD);
NOTE: Use upper-case for the first letter of the API name here.
Add the new record after the very last LWM one.
<repo_root>/src/coreclr/tools/superpmi/superpmi-shared/methodcontext.h:
Define 3 methods in this header file inside class MethodContext class (at the end of its definition).
The methods are prefixed with rec* (record), dmp* (dump to console) and rep* (replay). Example
+ void recGetUnboxedEntry(CORINFO_METHOD_HANDLE ftn, bool* requiresInstMethodTableArg, CORINFO_METHOD_HANDLE result);
+ void dmpGetUnboxedEntry(DWORDLONG key, DLD value);
+ CORINFO_METHOD_HANDLE repGetUnboxedEntry(CORINFO_METHOD_HANDLE ftn, bool* requiresInstMethodTableArg);
Now add a new element to enum mcPackets enum in the same file. Example:
+ Packet_GetUnboxedEntry = <last value + 1>,
<repo_root>/src/coreclr/tools/superpmi/superpmi-shared/methodcontext.cpp:
Add the implementation of the 3 methods to methodcontext.cpp at the end of it.
Consider other similar methods in the file for reference. Do not change implementations of other methods in the file. Example:
+void MethodContext::recGetUnboxedEntry(CORINFO_METHOD_HANDLE ftn,
+ bool* requiresInstMethodTableArg,
+ CORINFO_METHOD_HANDLE result)
+{
+ // Initialize the "input - output" map if it is not already initialized
+ if (GetUnboxedEntry == nullptr)
+ {
+ GetUnboxedEntry = new LightWeightMap<DWORDLONG, DLD>();
+ }
+
+ // Create a key out of the input arguments
+ DWORDLONG key = CastHandle(ftn);
+ DLD value;
+ value.A = CastHandle(result);
+
+ // Create a value out of the return value and out parameters
+ if (requiresInstMethodTableArg != nullptr)
+ {
+ value.B = (DWORD)*requiresInstMethodTableArg ? 1 : 0;
+ }
+ else
+ {
+ value.B = 0;
+ }
+
+ // Save it to the map
+ GetUnboxedEntry->Add(key, value);
+ DEBUG_REC(dmpGetUnboxedEntry(key, value));
+}
+void MethodContext::dmpGetUnboxedEntry(DWORDLONG key, DLD value)
+{
+ // Dump key and value to the console for debug purposes.
+ printf("GetUnboxedEntry ftn-%016" PRIX64 ", result-%016" PRIX64 ", requires-inst-%u", key, value.A, value.B);
+}
+CORINFO_METHOD_HANDLE MethodContext::repGetUnboxedEntry(CORINFO_METHOD_HANDLE ftn, bool* requiresInstMethodTableArg)
+{
+ // Create a key out of the input arguments
- Add a new function to
<repo_root>/src/coreclr/tools/superpmi/superpmi/icorjitinfo.cpp that calls the rep* method. Example:
+CORINFO_METHOD_HANDLE MyICJI::getUnboxedEntry(CORINFO_METHOD_HANDLE ftn, bool* requiresInstMethodTableArg)
+{
+ jitInstance->mc->cr->AddCall("getUnboxedEntry");
+ CORINFO_METHOD_HANDLE result = jitInstance->mc->repGetUnboxedEntry(ftn, requiresInstMethodTableArg);
+ return result;
+}
- Add a new function to
<repo_root>/src/coreclr/tools/superpmi/superpmi-shim-collector/icorjitinfo.cpp that calls the rec* method. Example:
+CORINFO_METHOD_HANDLE interceptor_ICJI::getUnboxedEntry(CORINFO_METHOD_HANDLE ftn, bool* requiresInstMethodTableArg)
+{
+ mc->cr->AddCall("getUnboxedEntry");
+ bool localRequiresInstMethodTableArg = false;
+ CORINFO_METHOD_HANDLE result = original_ICorJitInfo->getUnboxedEntry(ftn, &localRequiresInstMethodTableArg);
+ mc->recGetUnboxedEntry(ftn, &localRequiresInstMethodTableArg, result);
+ if (requiresInstMethodTableArg != nullptr)
+ {
+ *requiresInstMethodTableArg = localRequiresInstMethodTableArg;
+ }
+ return result;
+}
4 — Definition of Done (self-check list)
