On the 0x212 day of Apache Harmony Tonny Lau wrote: > 30 Oct 2006 11:03:50 +0600, Egor Pasko <[EMAIL PROTECTED]>: > > > > On the 0x212 day of Apache Harmony Tonny Lau wrote: > > > Hi, > > > > > > I want to override some specific java methods with native fast path > > > implementations. So I try to override them in > > > compile_do_compilation_jit()(vm/vmcore/src/jit/compile.cpp), that is, > > > I add several entries in > > > > > _stub_override_entries_base[](vm/vmcore/src/util/ia32/base/compile_IA32.cpp), > > > and lookup this table > > > before invoke jit->compile_method_with_params(). > > > > This mechanism is not used (AFAIR and AFAICanSeeNow). The alternative > > way is to support your "magics" within each JIT. (Mikhail does things > > like that in OPT just from JavaByteCodeTranslator.cpp (see > > isMagicClass(...)) > > > Thanks! I'll look it. > > > It works for JET, but failed when OPT recompile these method. Does the OPT > > > go different path? If so, how can I override it? Does anyone can help > > me? > > > > how does it fail? did you try it with -Xem:opt? (That's what I tend > > to always ask about:) > > > > Just a guess: OPT expects some profile from JET, but cannot find any. > > > I mean, the overriding succeeds when I use JET only, i.e., "java - > Dem.properties=jet ...". If I use the default configuration "java ...", at > the beginning, the overriding is successful because the code is compiled by > JET. But later, when the EM invoke OPT to re-compile the hot code, the > overriding does not work any longer. It fall back to the original java code.
yeah, that looks much like inlining :) hence, fixable in the inliner > So, where do you think is the best place in OPT for the overriding > code? I suppose overriding==your-custom-native-code? Can your code be written using ordinary (address) arithmetic and simple mem allocations? If so, then the best method is to write it in Java using *org.vmmagic.unboxed* package that Mikhail has just implemented. Otherwise you can hack around JavaByteCodeTranslator::invokevirtual and recognize your "magic" methods there, replacing the method's invokation with your custom IR. >And is there a common path for both JET and OPT? No. Especially when you take OPT's inlining into consideration. OPT can inline using only OPTs mechanisms that JET is not aware of. But *org.vmmagic.unboxed* can help you since it is supported both in JET and OPT. -- Egor Pasko, Intel Managed Runtime Division
