From 5681594c83c2ba9a2c0e21983cac0f161ff95f02 Mon Sep 17 00:00:00 2001 From: letouzey Date: Sun, 3 Apr 2011 11:23:31 +0000 Subject: Lazy loading of opaque proofs: fast as -dont-load-proofs without its drawbacks The recent experiment with -dont-load-proofs in the stdlib showed that this options isn't fully safe: some axioms were generated (Include ? functor application ? This is still to be fully understood). Instead, I've implemented an idea of Yann: only load opaque proofs when we need them. This is almost as fast as -dont-load-proofs (on the stdlib, we're now 15% faster than before instead of 20% faster with -dont-load-proofs), but fully compatible with Coq standard behavior. Technically, the const_body field of Declarations.constant_body now regroup const_body + const_opaque + const_inline in a ternary type. It is now either: - Undef : an axiom or parameter, with an inline info - Def : a transparent definition, with a constr_substituted - OpaqueDef : an opaque definition, with a lazy constr_substitued Accessing the lazy constr of an OpaqueDef might trigger the read on disk of the final section of a .vo, where opaque proofs are located. Some functions (body_of_constant, is_opaque, constant_has_body) emulate the behavior of the old fields. The rest of Coq (including the checker) has been adapted accordingly, either via direct access to the new const_body or via these new functions. Many places look nicer now (ok, subjective notion). There are now three options: -lazy-load-proofs (default), -force-load-proofs (earlier semantics), -dont-load-proofs. Note that -outputstate now implies -force-load-proofs (otherwise the marshaling fails on some delayed lazy). On the way, I fixed what looked like a bug : a module type (T with Definition x := c) was accepted even when x in T was opaque. I also tried to clarify Subtyping.check_constant. git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@13952 85f007b7-540e-0410-9357-904b9bb8a0f7 --- checker/safe_typing.ml | 42 ++++++++++++++++++++---------------------- 1 file changed, 20 insertions(+), 22 deletions(-) (limited to 'checker/safe_typing.ml') diff --git a/checker/safe_typing.ml b/checker/safe_typing.ml index eaf2aae80..bc067dc5f 100644 --- a/checker/safe_typing.ml +++ b/checker/safe_typing.ml @@ -77,15 +77,18 @@ type compiled_library = module LightenLibrary : sig type table type lightened_compiled_library - val load : load_proof:bool -> (unit -> table) - -> lightened_compiled_library -> compiled_library + val load : table -> lightened_compiled_library -> compiled_library end = struct (* The table is implemented as an array of [constr_substituted]. - Thus, its keys are integers which can be easily embedded inside - [constr_substituted]. This way the [compiled_library] type does - not have to be changed. *) + Keys are hence integers. To avoid changing the [compiled_library] + type, we brutally encode integers into [lazy_constr]. This isn't + pretty, but shouldn't be dangerous since the produced structure + [lightened_compiled_library] is abstract and only meant for writing + to .vo via Marshal (which doesn't care about types). + *) type table = constr_substituted array + let key_of_lazy_constr (c:lazy_constr) = (Obj.magic c : int) (* To avoid any future misuse of the lightened library that could interpret encoded keys as real [constr_substituted], we hide @@ -115,8 +118,8 @@ end = struct } and traverse_struct struc = let traverse_body (l,body) = (l,match body with - | SFBconst ({const_opaque=true} as x) -> - SFBconst {x with const_body = on_opaque_const_body x.const_body } + | (SFBconst cb) when is_opaque cb -> + SFBconst {cb with const_body = on_opaque_const_body cb.const_body} | (SFBconst _ | SFBmind _ ) as x -> x | SFBmodule m -> @@ -148,21 +151,16 @@ end = struct [constr_substituted]. Otherwise, we set the [const_body] field to [None]. *) - let load ~load_proof (get_table : unit -> table) lightened_library = - let decode_key : constr_substituted option -> constr_substituted option = - if load_proof then - let table = get_table () in - function Some cterm -> - Some (table.( - try - match Declarations.force_constr cterm with - | Term.Rel key -> key - | _ -> assert false - with _ -> assert false - )) - | _ -> None - else - fun _ -> None + let load table lightened_library = + let decode_key = function + | Undef _ | Def _ -> assert false + | OpaqueDef k -> + let k = key_of_lazy_constr k in + let body = + try table.(k) + with _ -> error "Error while retrieving an opaque body" + in + OpaqueDef (lazy_constr_from_val body) in traverse_library decode_key lightened_library -- cgit v1.2.3