Yuan, Rotor always uses JIT_NewFast to allocate objects. There is a mechanism to allow for use of highly tuned per platforms allocators via use of getNewHelper(...), but it is not used in Rotor for portability reasons.
Here is x86 dissasembly for the following IL: IL_0000: newobj instance void MainApp::.ctor() IL_0005: stloc.0 03457bb1 b8b844d700 mov eax,0xd744b8 // MT for MainApp 03457bb6 50 push eax 03457bb7 b83a4c9500 mov eax,0x954c3a // Address of JIT_NewFast 03457bbc ffd0 call eax 03457bbe 83c404 add esp,0x4 03457bc1 8bf0 mov esi,eax // Save the pointer to the 03457bc3 8bc8 mov ecx,eax // blank object in esi 03457bc5 51 push ecx 03457bc6 b8fc44d700 mov eax,0xd744fc 03457bcb ff10 call dword ptr [eax]// Call the constructor 03457bcd 83c404 add esp,0x4 03457bd0 8bc6 mov eax,esi // Get the object ref from 03457bd2 be00000000 mov esi,0x0 // esi and store it in a 03457bd7 8945f0 mov [ebp-0x10],eax // local (Note esi is set to NULL because it is in the root set for the GC) The code paths for allocating valuetypes and arrays are different. Let me know which one you are interested in. Thanks, Vladimir This posting is provided "AS IS" with no warranties, and confers no rights. -----Original Message----- From: Discussion of the Rotor Shared Source CLI implementation [mailto:[EMAIL PROTECTED] On Behalf Of Yuan Yu Sent: Friday, August 01, 2003 6:12 PM To: [EMAIL PROTECTED] Subject: [DOTNET-ROTOR] How does FJit::compileCEE_NEWOBJ work? I have been trying to understand how the newobj instruction is jitted. For a simple class like class Foo { int x = 5; } and an instruction newobj instance void Foo Rotor calls FJit::compileCEE_NEWOBJ, and goes to the "allocate normal object" case where the first line is helper_ftn = jitInfo->getHelperFtn(jitInfo->getNewHelper(targetClass, methodHandle)); The value of jitInfo->getNewHelper(targetClass, methodHandle) appears to be CORINFO_HELP_NEWSFAST, and, according to the table hlpFuncTable, it seems to map to JIT_NewFast. So, I thought the helper function helper_ftn must have been JIT_NewFast. However, it does not seem to be the case. So, what is the value of helper_ftn? Thanks, -Yuan
