[Mono-bugs] [Bug 69182][Wis] New - Use only one trampoline for jitting virtual functions

bugzilla-daemon@bugzilla.ximian.com bugzilla-daemon@bugzilla.ximian.com
Sat, 6 Nov 2004 12:13:23 -0500 (EST)

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Changed by bmaurer@users.sf.net.


--- shadow/69182	2004-11-06 12:13:23.000000000 -0500
+++ shadow/69182.tmp.10348	2004-11-06 12:13:23.000000000 -0500
@@ -0,0 +1,33 @@
+Bug#: 69182
+Product: Mono: Runtime
+Version: 1.1
+OS Details: 
+Status: NEW   
+Priority: Wishlist
+Component: misc
+AssignedTo: mono-bugs@ximian.com                            
+ReportedBy: bmaurer@users.sf.net               
+QAContact: mono-bugs@ximian.com
+TargetMilestone: ---
+Summary: Use only one trampoline for jitting virtual functions
+Today, when we create a vtable, we create a new trampoline for every
+virtual function in the method. However, it is possible to create one
+trampoline for all of them.
+The code for calling a virtual function is something like:
+mov eax, [obj+vtable_offset]
+call [eax+method_offset]
+In the trampoline, we can take eax, which will hold the MonoVTable for the
+class. Then, we can decode method_offset. From there, we will know what
+MonoMethod* we want to compile. Thus, the trampoline is not specific to the
+virtual call.
+Jikes uses this technique, and probably other runtimes do as well.