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rename <glil-asm> to <glil-program>

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* module/language/glil.scm (<glil-program>): Rename from <glil-asm>.

* module/language/ghil/compile-glil.scm (codegen):
* module/language/glil.scm (parse-glil, unparse-glil):
* module/language/glil/compile-objcode.scm (preprocess, codegen): Adapt
  to naming change.
This commit is contained in:
Andy Wingo 2009-01-11 12:14:07 +01:00
parent c2c82b62f4
commit c850030fdd
4 changed files with 286 additions and 75 deletions
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339
doc/ref/compiler.texi
View file

@ -259,98 +259,301 @@ time. Useful for supporting some forms of dynamic compilation. Returns
@node GHIL
@subsection GHIL
structured, typed intermediate language, close to scheme
with an s-expression representation
Guile High Intermediate Language (GHIL) is a structured intermediate
language that is close in expressive power to Scheme. It is an
expanded, pre-analyzed Scheme.
,lang ghil
GHIL is ``structured'' in the sense that its representation is based
on records, not S-expressions. This gives a rigidity to the language
that ensures that compiling to a lower-level language only requires a
limited set of transformations. Practically speaking, consider the
GHIL type, @code{<ghil-quote>}, which has fields named @code{env},
@code{loc}, and @code{exp}. Instances of this type are records created
via @code{make-ghil-quote}, and whose fields are accessed as
@code{ghil-quote-env}, @code{ghil-quote-loc}, and
@code{ghil-quote-exp}. There is also a predicate, @code{ghil-quote?}.
@xref{Records}, for more information on records.
document reified format, as it's more interesting, and gives you an idea
Expressions of GHIL name their environments explicitly, and all
variables are referenced by identity in addition to by name.
@code{(language ghil)} defines a number of routines to deal explicitly
with variables and environments:
all have environment and location pointers
@deftp {Scheme Variable} <ghil-toplevel-env> [table='()]
A toplevel environment. The @var{table} holds all toplevel variables
that have been resolved in this environment.
@end deftp
@deftp {Scheme Variable} <ghil-env> parent [table='()] [variables='()]
A lexical environment. @var{parent} will be the enclosing lexical
environment, or a toplevel environment. @var{table} holds an alist
mapping symbols to variables bound in this environment, while
@var{variables} holds a cumulative list of all variables ever defined
in this environment.
@deffn {GHIL Expression} quote exp
A quoted expression.
Lexical environments correspond to procedures. Bindings introduced
e.g. by Scheme's @code{let} add to the bindings in a lexical
environment. An example of a case in which a variable might be in
@var{variables} but not in @var{table} would be a variable that is in
the same procedure, but is out of scope.
@end deftp
@deftp {Scheme Variable} <ghil-var> env name kind [index=#f]
A variable. @var{kind} is one of @code{argument}, @code{local},
@code{external}, @code{toplevel}, @code{public}, or @code{private};
see the procedures below for more information. @var{index} is used in
compilation.
@end deftp
@deffn {Scheme Procedure} ghil-var-is-bound? env sym
Recursively look up a variable named @var{sym} in @var{env}, and
return it or @code{#f} if none is found.
@end deffn
@deffn {GHIL Expression} quasiquote exp
A quasiquoted expression. The parse format understands the normal
@code{unquote} and @code{unquote-splicing} forms as in normal Scheme.
When constructing @var{exp} programmatically, you will need to call
@code{make-ghil-unquote} and @code{make-ghil-unquote-splicing} as
appropriate.
@deffn {Scheme Procedure} ghil-var-for-ref! env sym
Recursively look up a variable named @var{sym} in @var{env}, and
return it. If the symbol was not bound, return a new toplevel
variable.
@end deffn
@deffn {GHIL Expression} lambda syms rest meta . body
A closure. @var{syms} is the argument list, as a list of symbols.
@var{rest} is a boolean, which is @code{#t} iff the last argument is a
rest argument. @var{meta} is an association list of properties. The
actual @var{body} should be a list of GHIL expressions.
@deffn {Scheme Procedure} ghil-var-for-set! env sym
Like @code{ghil-var-for-ref!}, except that the returned variable will
be marked as @code{external}. @xref{Variables and the VM}.
@end deffn
@deffn {GHIL Expression} void
@deffn {Scheme Procedure} ghil-var-define! toplevel-env sym
Return an existing or new toplevel variable named @var{sym}.
@var{toplevel-env} must be a toplevel environment.
@end deffn
@deffn {Scheme Procedure} ghil-var-at-module! env modname sym interface?
Return a variable that will be resolved at runtime with respect to a
specific module named @var{modname}. If @var{interface?} is true, the
variable will be of type @code{public}, otherwise @code{private}.
@end deffn
@deffn {Scheme Procedure} call-with-ghil-environment env syms func
Bind @var{syms} to fresh variables within a new lexical environment
whose parent is @var{env}, and call @var{func} as @code{(@var{func}
@var{new-env} @var{new-vars})}.
@end deffn
@deffn {Scheme Procedure} call-with-ghil-bindings env syms func
Like @code{call-with-ghil-environment}, except the existing
environment @var{env} is re-used. For that reason, @var{func} is
invoked as @code{(@var{func} @var{new-vars})}
@end deffn
In the aforementioned @code{<ghil-quote>} type, the @var{env} slot
holds a pointer to the environment in which the expression occurs. The
@var{loc} slot holds source location information, so that errors
corresponding to this expression can be mapped back to the initial
expression in the higher-level language, e.g. Scheme. @xref{Compiled
Procedures}, for more information on source location objects.
GHIL also has a declarative serialization format, which makes writing
and reading it a tractable problem for the human mind. Since all GHIL
language constructs contain @code{env} and @code{loc} pointers, they
are left out of the serialization. (Serializing @code{env} structures
would be difficult, as they are often circular.) What is left is the
type of expression, and the remaining slots defined in the expression
type.
For example, an S-expression representation of the @code{<ghil-quote>}
expression would be:
@example
(quote 3)
@end example
It's deceptively like Scheme. The general rule is, for a type defined
as @code{<ghil-@var{foo}> env loc @var{slot1} @var{slot2}...}, the
S-expression representation will be @code{(@var{foo} @var{slot1}
@var{slot2}...)}. Users may program with this format directly at the
REPL:
@example
scheme@@(guile-user)> ,language ghil
Guile High Intermediate Language (GHIL) interpreter 0.3 on Guile 1.9.0
Copyright (C) 2001-2008 Free Software Foundation, Inc.
Enter `,help' for help.
ghil@@(guile-user)> (call (ref +) (quote 32) (quote 10))
@result{} 42
@end example
For convenience, some slots are serialized as rest arguments; those
are noted below. The other caveat is that variables are serialized as
their names only, and not their identities.
@deftp {Scheme Variable} <ghil-void> env loc
The unspecified value.
@end deffn
@deffn {GHIL Expression} begin . body
Like Scheme's @code{begin}.
@end deffn
@deffn {GHIL Expression} bind syms exprs . body
Like a deconstructed @code{let}: each element of @var{syms} will be
bound to the corresponding GHIL expression in @var{exprs}.
@end deffn
@deffn {GHIL Expression} bindrec syms exprs . body
As @code{bind} is to @code{let}, so @code{bindrec} is to
@code{letrec}.
@end deffn
@deffn {GHIL Expression} set! sym val
Like Scheme's @code{set!}.
@end deffn
@deffn {GHIL Expression} define sym val
Like Scheme's @code{define}, but without the lambda sugar of course.
@end deffn
@deffn {GHIL Expression} if test then else
@end deftp
@deftp {Scheme Variable} <ghil-quote> env loc exp
A quoted expression.
Note that unlike in Scheme, there are no self-quoting expressions; all
constants must come from @code{quote} expressions.
@end deftp
@deftp {Scheme Variable} <ghil-quasiquote> env loc exp
A quasiquoted expression. The expression is treated as a constant,
except for embedded @code{unquote} and @code{unquote-splicing} forms.
@end deftp
@deftp {Scheme Variable} <ghil-unquote> env loc exp
Like Scheme's @code{unquote}; only valid within a quasiquote.
@end deftp
@deftp {Scheme Variable} <ghil-unquote-splicing> env loc exp
Like Scheme's @code{unquote-splicing}; only valid within a quasiquote.
@end deftp
@deftp {Scheme Variable} <ghil-ref> env loc var
A variable reference. Note that for purposes of serialization,
@var{var} is serialized as its name, as a symbol.
@end deftp
@deftp {Scheme Variable} <ghil-set> env loc var val
A variable mutation. @var{var} is serialized as a symbol.
@end deftp
@deftp {Scheme Variable} <ghil-define> env loc var val
A toplevel variable definition. See @code{ghil-var-define!}.
@end deftp
@deftp {Scheme Variable} <ghil-if> env loc test then else
A conditional. Note that @var{else} is not optional.
@end deffn
@deffn {GHIL Expression} and . exps
@end deftp
@deftp {Scheme Variable} <ghil-and> env loc . exps
Like Scheme's @code{and}.
@end deffn
@deffn {GHIL Expression} or . exps
@end deftp
@deftp {Scheme Variable} <ghil-or> env loc . exps
Like Scheme's @code{or}.
@end deffn
@deffn {GHIL Expression} mv-bind syms rest producer . body
@end deftp
@deftp {Scheme Variable} <ghil-begin> env loc . body
Like Scheme's @code{begin}.
@end deftp
@deftp {Scheme Variable} <ghil-bind> env loc vars exprs . body
Like a deconstructed @code{let}: each element of @var{vars} will be
bound to the corresponding GHIL expression in @var{exprs}.
Note that for purposes of the serialization format, @var{exprs} are
evaluated before the new bindings are added to the environment. For
@code{letrec} semantics, there also exists a @code{bindrec} parse
flavor. This is useful for writing GHIL at the REPL, but the
serializer does not currently have the cleverness needed to determine
whether a @code{<ghil-bind>} has @code{let} or @code{letrec}
semantics, and thus only serializes @code{<ghil-bind>} as @code{bind}.
@end deftp
@deftp {Scheme Variable} <ghil-mv-bind> env loc vars rest producer . body
Like Scheme's @code{receive} -- binds the values returned by
applying @code{producer}, which should be a thunk, to the
@code{lambda}-like bindings described by @var{syms} and @var{rest}.
@end deffn
@deffn {GHIL Expression} call proc . args
@code{lambda}-like bindings described by @var{vars} and @var{rest}.
@end deftp
@deftp {Scheme Variable} <ghil-lambda> env loc vars rest meta . body
A closure. @var{vars} is the argument list, serialized as a list of
symbols. @var{rest} is a boolean, which is @code{#t} iff the last
argument is a rest argument. @var{meta} is an association list of
properties. The actual @var{body} should be a list of GHIL
expressions.
@end deftp
@deftp {Scheme Variable} <ghil-call> env loc proc . args
A procedure call.
@end deffn
@deffn {GHIL Expression} mv-call producer consumer
@end deftp
@deftp {Scheme Variable} <ghil-mv-call> env loc producer consumer
Like Scheme's @code{call-with-values}.
@end deffn
@deffn {GHIL Expression} inline op . args
@end deftp
@deftp {Scheme Variable} <ghil-inline> env loc op . args
An inlined VM instruction. @var{op} should be the instruction name as
a symbol, and @var{args} should be its arguments, as GHIL expressions.
@end deffn
@deffn {GHIL Expression} values . values
@end deftp
@deftp {Scheme Variable} <ghil-values> env loc . values
Like Scheme's @code{values}.
@end deffn
@deffn {GHIL Expression} values* . values
@end deftp
@deftp {Scheme Variable} <ghil-values*> env loc . values
@var{values} are as in the Scheme expression, @code{(apply values .
@var{vals})}.
@end deffn
@deffn {GHIL Expression} compile-time-environment
@end deftp
@deftp {Scheme Variable} <ghil-reified-env> env loc
Produces, at runtime, a reification of the environment at compile
time.
@end deffn
time. Used in the implementation of Scheme's
@code{compile-time-environment}.
@end deftp
ghil environments
ghil-var-for-ref!, ghil-var-for-set!, ghil-var-define!, ghil-var-at-module!
GHIL implements a compiler to GLIL that recursively traverses GHIL
expressions, writing out GLIL expressions into a linear list. The
compiler also keeps some state as to whether the current expression is
in tail context, and whether its value will be used in future
computations. This state allows the compiler not to emit code for
constant expressions that will not be used (e.g. docstrings), and to
perform tail calls when in tail position.
some pre-optimization
Just as the Scheme to GHIL compiler introduced new hidden state---the
environment---the GHIL to GLIL compiler introduces more state, the
stack. While not represented explicitly, the stack is present in the
compilation of each GHIL expression: compiling a GHIL expression
should leave the runtime value stack in the same state. For example,
if the intermediate value stack has two elements before evaluating an
@code{if} expression, it should have two elements after that
expression.
real name of the game is closure elimination -- fixing letrec
Interested readers are encouraged to read the implementation in
@code{(language ghil compile-glil)} for more details.
@node GLIL
@subsection GLIL
structured, typed intermediate language, close to object code
Guile Low Intermediate Language (GHIL) is a structured intermediate
language whose expressions closely mirror the functionality of Guile's
VM instruction set.
Its expression types are defined in @code{(language glil)}, and as
with GHIL, some of its fields parse as rest arguments.
@deftp {Scheme Variable} <glil-asm> nargs nrest nlocs nexts meta . body
vars is @code{(@var{nargs} @var{nrest} @var{nlocs} @var{next})}
@end deftp
@deftp {Scheme Variable} <glil-bind> . vars
vars is a list of @code{(@var{name} @var{type} @var{index})}
@end deftp
@deftp {Scheme Variable} <glil-mv-bind> vars rest
vars is a list of @code{(@var{name} @var{type} @var{index})}
@var{rest} is bool
@end deftp
@deftp {Scheme Variable} <glil-unbind>
closes binding
@end deftp
@deftp {Scheme Variable} <glil-source> loc
source information for the preceding expression
@end deftp
@deftp {Scheme Variable} <glil-void>
push the unspecified value
@end deftp
@deftp {Scheme Variable} <glil-const> obj
A constant value -- @var{obj} can be anything serializable -- number,
string, symbol, keyword, null, bool, char, or pair or vector or list thereof
@end deftp
@deftp {Scheme Variable} <glil-argument> op index
access an argument on the stack. op is ref or set.
@end deftp
@deftp {Scheme Variable} <glil-local> op index
access a local var (on the stack). op is ref or set.
@end deftp
@deftp {Scheme Variable} <glil-external> op depth index
access a heap-allocated var, depth is the number of environments deep,
index is the position within the env. op is ref or set.
@end deftp
@deftp {Scheme Variable} <glil-toplevel> op name
access a toplevel var. if compiling at the toplevel, will translate to
a link-now + variable-ref,set; otherwise toplevel-ref/set with the
object vector cache. also op == define.
@end deftp
@deftp {Scheme Variable} <glil-module> op mod name public?
access a module var, ref/set, like ...
@end deftp
@deftp {Scheme Variable} <glil-label> label
make a new label. @var{label} can be any scheme value, and should be
unique.
@end deftp
@deftp {Scheme Variable} <glil-branch> inst label
branch to a label. @var{label} should be a @code{<ghil-label>}.
@code{inst} is a branching instruction: @code{br-if}, @code{br}, etc.
@end deftp
@deftp {Scheme Variable} <glil-call> inst nargs
This expression is perhaps misnamed, as it does not correspond to
function calls. @code{<glil-call>} invokes the VM instruction named
@var{inst}, noting that it is called with @var{nargs} stack arguments.
@end deftp
@deftp {Scheme Variable} <glil-mv-call> nargs ra
Multiple-values call, ra should be an offset for the mvra, in bytes (?)
@end deftp
passes through the env
@ -380,6 +583,14 @@ AOT compilation
link to what dybvig did
real name of the game is closure elimination -- fixing letrec
possibilities: box ``external'' values individually, then allocate on
stack instead of in a list. HOCS p3. Procedure slots in symbols?
Optimized case-lambda to avoid creating lists? Underflow / overflow
implementation of continuations? JIT / AOT compilers. R6RS especially
wrt modules and macros. Built-in syncase. Letrec optimizations.
profiling
startup time

2
module/language/ghil/compile-glil.scm
View file

@ -434,7 +434,7 @@
;; compile body
(comp body #t #f)
;; create GLIL
(make-glil-asm
(make-glil-program
(length vars) (if rest 1 0) (length locs) (length exts)
meta (reverse! stack)))))))

16
module/language/glil.scm
View file

@ -23,9 +23,9 @@
#:use-module (system base syntax)
#:use-module (system base pmatch)
#:export
(<glil-asm> make-glil-asm glil-asm?
glil-asm-nargs glil-asm-nrest glil-asm-nlocs glil-asm-nexts
glil-asm-meta glil-asm-body
(<glil-program> make-glil-program glil-program?
glil-program-nargs glil-program-nrest glil-program-nlocs glil-program-nexts
glil-program-meta glil-program-body
<glil-bind> make-glil-bind glil-bind?
glil-bind-vars
@ -77,7 +77,7 @@
(define-type (<glil> #:printer print-glil)
;; Meta operations
(<glil-asm> nargs nrest nlocs nexts meta body)
(<glil-program> nargs nrest nlocs nexts meta body)
(<glil-bind> vars)
(<glil-mv-bind> vars rest)
(<glil-unbind>)
@ -100,8 +100,8 @@
(define (parse-glil x)
(pmatch x
((asm ,nargs ,nrest ,nlocs ,nexts ,meta . ,body)
(make-glil-asm nargs nrest nlocs nexts meta (map parse-glil body)))
((program ,nargs ,nrest ,nlocs ,nexts ,meta . ,body)
(make-glil-program nargs nrest nlocs nexts meta (map parse-glil body)))
((bind . ,vars) (make-glil-bind vars))
((mv-bind ,vars . ,rest) (make-glil-mv-bind vars (map parse-glil rest)))
((unbind) (make-glil-unbind))
@ -123,8 +123,8 @@
(define (unparse-glil glil)
(record-case glil
;; meta
((<glil-asm> nargs nrest nlocs nexts meta body)
`(asm ,nargs ,nrest ,nlocs ,nexts ,meta ,@(map unparse-glil body)))
((<glil-program> nargs nrest nlocs nexts meta body)
`(program ,nargs ,nrest ,nlocs ,nexts ,meta ,@(map unparse-glil body)))
((<glil-bind> vars) `(bind ,@vars))
((<glil-mv-bind> vars rest) `(mv-bind ,vars ,@rest))
((<glil-unbind>) `(unbind))

4
module/language/glil/compile-objcode.scm
View file

@ -55,7 +55,7 @@
(define (preprocess x e)
(record-case x
((<glil-asm> nargs nrest nlocs nexts meta body)
((<glil-program> nargs nrest nlocs nexts meta body)
(let* ((venv (make-venv #:parent e #:nexts nexts #:closure? #f))
(body (map (lambda (x) (preprocess x venv)) body)))
(make-vm-asm #:venv venv #:glil x #:body body)))
@ -109,7 +109,7 @@
(define (codegen glil toplevel)
(record-case glil
((<vm-asm> venv glil body) (record-case glil ((<glil-asm> nargs nrest nlocs nexts meta) ; body?
((<vm-asm> venv glil body) (record-case glil ((<glil-program> nargs nrest nlocs nexts meta) ; body?
(let ((stack '())
(open-bindings '())
(closed-bindings '())