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\input texinfo	@c -*-texinfo-*-
@c %** start of header
@setfilename libjit.info
@settitle Just-In-Time Compiler Library
@setchapternewpage off
@c %** end of header

@dircategory Libraries
@direntry
* Libjit: (libjit).                Just-In-Time Compiler Library
@end direntry

@ifinfo
The libjit library assists with the process of building
Just-In-Time compilers for languages, virtual machines,
and emulators.

Copyright @copyright{} 2004 Southern Storm Software, Pty Ltd
@end ifinfo

@titlepage
@sp 10
@center @titlefont{Just-In-Time Compiler Library}

@vskip 0pt plus 1fill
@center{Copyright @copyright{} 2004 Southern Storm Software, Pty Ltd}
@end titlepage

@syncodeindex fn cp
@syncodeindex vr cp
@syncodeindex tp cp

@c -----------------------------------------------------------------------

@node Top, Introduction, , (dir)
@menu
* Introduction::            Introduction and rationale for libjit
* Features::                Features of libjit
* Tutorials::               Tutorials in using libjit
* Initialization::          Initializing the JIT
* Functions::               Building and compiling functions with the JIT
* Types::                   Manipulating system types
* Values::                  Working with temporary values in the JIT
* Instructions::            Working with instructions in the JIT
* Basic Blocks::            Working with basic blocks in the JIT
* Intrinsics::              Intrinsic functions available to libjit users
* Exceptions::              Handling exceptions
* Breakpoint Debugging::    Hooking a breakpoint debugger into libjit
* ELF Binaries::            Manipulating ELF binaries
* Utility Routines::        Miscellaneous utility routines
* Diagnostic Routines::     Diagnostic routines
* C++ Interface::           Using libjit from C++
* Porting::                 Porting libjit to new architectures
* Index::                   Index of concepts and facilities
@end menu

@c -----------------------------------------------------------------------

@node Introduction, Features, Top, Top
@chapter Introduction and rationale for libjit
@cindex Introduction

Just-In-Time compilers are becoming increasingly popular for executing
dynamic languages like Perl and Python and for semi-dynamic languages
like Java and C#.  Studies have shown that JIT techniques can get close to,
and sometimes exceed, the performance of statically-compiled native code.

However, there is a problem with current JIT approaches.  In almost every
case, the JIT is specific to the object model, runtime support library,
garbage collector, or bytecode peculiarities of a particular system.
This inevitably leads to duplication of effort, where all of the good
JIT work that has gone into one virtual machine cannot be reused in another.

JIT's are not only useful for implementing languages.  They can also be used
in other programming fields.  Graphical applications can achieve greater
performance if they can compile a special-purpose rendering routine
on the fly, customized to the rendering task at hand, rather than using
static routines.  Needless to say, such applications have no need for
object models, garbage collectors, or huge runtime class libraries.

Most of the work on a JIT is concerned with arithmetic, numeric type
conversion, memory loads/stores, looping, performing data flow analysis,
assigning registers, and generating the executable machine code.