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feat(BV): Only store domains on variable parts #1152
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Note: this fixes rare crashes with bitvector fields in ADTs/records (previous implementation incorrectly assumed that |
src/lib/reasoners/bitv_rel.ml
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Assuming [x] and [y] are bit-vectors of width 2: | ||
- [101 @ x] is [x + 10100] ; | ||
- [10 @ x @ 01] is [(x @ 00) + 100001] ; | ||
- [10 @ y<0, 0> @ y<1, 1>] is [(y<0, 0> @ y<1>1) + 1000] ; |
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I do not understand the notation x<.., ...>
. Is it an extraction? I guess there is a typo with y<1>1
instead of y<1, 1>
?
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Yes, this is the syntax that is used elsewhere in documentation comments for extraction (and indeed there is a typo, it should be y<1, 1>
). I will clarify.
src/lib/reasoners/rel_utils.ml
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[domain]. The explanation [ex] justifies that the [domain] applies to | ||
the entry's key. |
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This documentation is outdated. There is no ex
argument.
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True — the justification is in the domain.
src/lib/reasoners/rel_utils.ml
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(** [entry t k] returns the [handle] associated with [k]. | ||
|
||
There is a unique entry associated with each key [k] that is created | ||
on-the-fly when [handle t k] is called for the first time. |
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There is no handle
function in this module. I guess you meant entry t k
?
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Yes, handle
was renamed to entry
at some point.
src/lib/reasoners/rel_utils.ml
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|
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The domain associated with the entry is initialized from the underlying | ||
persistent domain the first time it is accessed, and updated with | ||
[update]. *) |
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What is update
here? Cannot find it.
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It should be set_domain
, will fix.
src/lib/reasoners/rel_utils.ml
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val add : X.t -> W.t -> t -> t | ||
(** [add x w r] adds the tuple [(x, w)] to the relation. *) | ||
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val add_many : X.t -> W.Set.t -> t -> t |
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Please add documentation
src/lib/reasoners/rel_utils.ml
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val add_many : X.t -> W.Set.t -> t -> t | ||
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val range : X.t -> t -> W.Set.t |
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Same here
src/lib/reasoners/rel_utils.ml
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DMC.needs_propagation t.composites || | ||
not (W.Set.is_empty t.triggers) | ||
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let variables { variables ; _ } = variables |
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For this kind of function, I am used to add [@inline always]
, but I am not sure it is necessary?
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It's probably going to be inlined anyways. I can add the annotation.
src/lib/reasoners/rel_utils.ml
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let variables { variables ; _ } = variables | ||
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let parents { parents ; _ } = parents |
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Same question for this one
I still believe the code would be easier to read with less functors and signatures. I understand your argument. It is probably easier to write it like this for you but reading the file |
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I still believe the code would be easier to read with less functors and signatures.
I have:
- Removed the
EphemeralMap
functor that turned out not to be useful - Merged the OffsetDomain and CompositeDomain signature into the Domain signature (the goal was to be able to extend the code to domains such as ADT constructors, which don't have an offset and are never composite, but that is not really an useful generalization at the moment)
- Merged AtomicType and CompositeType into the NormalForm signature (I intended to do this one prior to submitting the PR but forgot to actually do it)
- Removed the UfHandle functor in favor of a
Canon
sub-module inDomains_make.Ephemeral
- Inlined the
HandleNotations
functor into theEphemeralDomainMap
signature (I was not really happy with this functor in the first place; the goal was to avoid code duplication for the definition ofupdate
but all solutions I found, includingHandleNotations
, were too clunky and verbose, and the code forupdate
is small, so I think it's OK to duplicate here) - Renamed the
BinRel
functor toWatchMap
to make it less abstract, and removed some functions from it that were unused.
I think the remaining abstractions (except for WatchMap
) are necessary to be able to share the implementation between interval/bitlist domains and (in the future) between bit-vector/arithmetic normal forms. I am not too happy with the remaining WatchMap
functor but I don't have a good solution to avoid it without significant changes.
It is probably easier to write it like this for you
It is not that it is easier to write but that I find it easier to understand code with small encapsulated abstractions. I agree I went a little overboard here though, hopefully it is better now.
reading the file Rel_utils gives me the same feeling that reading Bourbaki, a bunch of abstract axioms before reaching the real stuff.
That is a common and unfortunate side-effect of OCaml processing definitions in order, and the solution is to read from the bottom up — OCaml code reads like a research paper, out of order. I have moved the signature definitions to a new Domains_intf
module, and the implementation itself to a new Domains
module.
src/lib/reasoners/bitv_rel.ml
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Assuming [x] and [y] are bit-vectors of width 2: | ||
- [101 @ x] is [x + 10100] ; | ||
- [10 @ x @ 01] is [(x @ 00) + 100001] ; | ||
- [10 @ y<0, 0> @ y<1, 1>] is [(y<0, 0> @ y<1>1) + 1000] ; |
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Yes, this is the syntax that is used elsewhere in documentation comments for extraction (and indeed there is a typo, it should be y<1, 1>
). I will clarify.
src/lib/reasoners/rel_utils.ml
Outdated
[domain]. The explanation [ex] justifies that the [domain] applies to | ||
the entry's key. |
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True — the justification is in the domain.
src/lib/reasoners/rel_utils.ml
Outdated
(** [entry t k] returns the [handle] associated with [k]. | ||
|
||
There is a unique entry associated with each key [k] that is created | ||
on-the-fly when [handle t k] is called for the first time. |
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Yes, handle
was renamed to entry
at some point.
src/lib/reasoners/rel_utils.ml
Outdated
|
||
The domain associated with the entry is initialized from the underlying | ||
persistent domain the first time it is accessed, and updated with | ||
[update]. *) |
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It should be set_domain
, will fix.
src/lib/reasoners/rel_utils.ml
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DMC.needs_propagation t.composites || | ||
not (W.Set.is_empty t.triggers) | ||
|
||
let variables { variables ; _ } = variables |
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It's probably going to be inlined anyways. I can add the annotation.
This patch changes the way that bit-vector domains are stored in order to share domains between multiple bit-vectors with the same variable part, including across different bit-width. Currently, if we had terms [x], [00 @ x], and [10 @ x], we would store domains for each of these. With this patch, we only store a domain for [x] and rebuild the domains for [00 @ x] and [10 @ x] dynamically; we do this by computing normal forms composed of a variable part ([x] here) and a constant offset (either [0] or [10]). This reduces the number of variables handled by the system (which is important for global domains such as global difference) and reduces the number of trivial propagations. Note that this patch is not reverting OCamlPro#1044. In particular, we are considering [x @ y] as a unique (composite) variable built up from the atomic variables [x] and [y] (in the same way that the polynomial [x + y] is built up from the monomial [x] and [y] in the IntervalCalculus module; in fact, the implementation is intentionally abstracted in order to be useable with polynomials). This is necessary because, as noted in OCamlPro#1044, the interval domain for [x @ y] cannot be built reconstructed precisely from the interval domains for [x] and [y]. The patch includes a bit of refactoring of the way we handle constraints; notably, instead of aggressively substituting constraints, we now store the original constraint and call [Uf.find] at propagation time. This avoids having to define a substitution operation on normal forms and allows storing the constraint dependencies directly inside the domain (in the previous design, we could not do it easily without repeating the expensive substitution of constraint arguments).
Co-authored-by: Pierrot <tiky.halbaroth@gmail.com>
In the current state of both the PR and the |
Actually, I can just fold |
Thanks for your effort, I will do a second pass now and we can merge :) |
CHANGES: ### Command-line interface - Enable FPA theory by default (OCamlPro/alt-ergo#1177) - Remove deprecated output channels (OCamlPro/alt-ergo#782) - Deprecate the --use-underscore since it produces models that are not SMT-LIB compliant (OCamlPro/alt-ergo#805) - Add --dump-models-on to dump models on a specific output channel (OCamlPro/alt-ergo#838) - Use consistent return codes (OCamlPro/alt-ergo#842) - Add --continue-on-error flag to set the SMT-LIB error behavior (OCamlPro/alt-ergo#853) - Make dolmen the default value for the --frontend option (OCamlPro/alt-ergo#857) - Restore functionality to broken `--profiling` option (OCamlPro/alt-ergo#947) - Add bare-bones support for interactive input in SMT-LIB format (OCamlPro/alt-ergo#949) - Less confusing behavior on timeout (OCamlPro/alt-ergo#982, OCamlPro/alt-ergo#984) - Add `--strict` option for SMT-LIB compliant mode (OCamlPro/alt-ergo#916, OCamlPro/alt-ergo#1133) - Deprecate `sum`, `typing` and `warnings` debug flags (OCamlPro/alt-ergo#1204) ### SMT-LIB support - Add support for the many new SMT-LIB commands (OCamlPro/alt-ergo#837, OCamlPro/alt-ergo#848, OCamlPro/alt-ergo#852, OCamlPro/alt-ergo#863, OCamlPro/alt-ergo#911, OCamlPro/alt-ergo#942, OCamlPro/alt-ergo#945, OCamlPro/alt-ergo#961, OCamlPro/alt-ergo#975, OCamlPro/alt-ergo#1069) - Expose the FPA rounding builtin in the SMT-LIB format (OCamlPro/alt-ergo#876, OCamlPro/alt-ergo#1135) - Allow changing the SAT solver using (set-option) (OCamlPro/alt-ergo#880) - Add support for the `:named` attribute (OCamlPro/alt-ergo#957) - Add support for quoted identifiers (OCamlPro/alt-ergo#909, OCamlPro/alt-ergo#972) - Add support for naming lemmas in SMT-LIB syntax (OCamlPro/alt-ergo#1141, OCamlPro/alt-ergo#1143) ### Model generation - Use post-solve SAT environment in model generation, fixing issues where incorrect models were generated (OCamlPro/alt-ergo#789) - Restore support for records in models (OCamlPro/alt-ergo#793) - Use abstract values instead of dummy values in models where the actual value does not matter (OCamlPro/alt-ergo#804, OCamlPro/alt-ergo#835) - Use fresh names for all abstract values to prevent accidental captures (OCamlPro/alt-ergo#811) - Add support for model generation with the default CDCL solver (OCamlPro/alt-ergo#829) - Support model generation for the BV theory (OCamlPro/alt-ergo#841, OCamlPro/alt-ergo#968) - Add support for optimization (MaxSMT / OptiSMT) with lexicographic Int and Real objectives (OCamlPro/alt-ergo#861, OCamlPro/alt-ergo#921) - Add a SMT-LIB printer for expressions (OCamlPro/alt-ergo#952, OCamlPro/alt-ergo#981, OCamlPro/alt-ergo#1082, OCamlPro/alt-ergo#931, OCamlPro/alt-ergo#932) - Ensure models have a value for all constants in the problem (OCamlPro/alt-ergo#1019) - Fix a rare soundness issue with integer constraints when model generation is enabled (OCamlPro/alt-ergo#1025) - Support model generation for the ADT theory (OCamlPro/alt-ergo#1093, OCamlPro/alt-ergo#1153) ### Theory reasoning - Add word-level propagators for the BV theory (OCamlPro/alt-ergo#944, OCamlPro/alt-ergo#1004, OCamlPro/alt-ergo#1007, OCamlPro/alt-ergo#1010, OCamlPro/alt-ergo#1011, OCamlPro/alt-ergo#1012, OCamlPro/alt-ergo#1040, OCamlPro/alt-ergo#1044, OCamlPro/alt-ergo#1054, OCamlPro/alt-ergo#1055, OCamlPro/alt-ergo#1056, OCamlPro/alt-ergo#1057, OCamlPro/alt-ergo#1065, OCamlPro/alt-ergo#1073, OCamlPro/alt-ergo#1144, OCamlPro/alt-ergo#1152) - Add interval domains and arithmetic propagators for the BV theory (OCamlPro/alt-ergo#1058, OCamlPro/alt-ergo#1083, OCamlPro/alt-ergo#1084, OCamlPro/alt-ergo#1085) - Native support for bv2nat of bit-vector normal forms (OCamlPro/alt-ergo#1154) - Fix incompleteness issues in the BV solver (OCamlPro/alt-ergo#978, OCamlPro/alt-ergo#979) - Abstract more arguments of AC symbols to avoid infinite loops when they contain other AC symbols (OCamlPro/alt-ergo#990) - Do not make irrelevant decisions in CDCL solver, improving performance slightly (OCamlPro/alt-ergo#1041) - Rewrite the ADT theory to use domains and integrate the enum theory into the ADT theory (OCamlPro/alt-ergo#1078, OCamlPro/alt-ergo#1086, OCamlPro/alt-ergo#1087, OCamlPro/alt-ergo#1091, OCamlPro/alt-ergo#1094, OCamlPro/alt-ergo#1138) - Rewrite the Intervals module entirely (OCamlPro/alt-ergo#1108) - Add maximize/minimize terms for matching (OCamlPro/alt-ergo#1166) - Internalize `sign_extend` and `repeat` (OCamlPro/alt-ergo#1192) - Run cross-propagators to completion (OCamlPro/alt-ergo#1221) - Support binary distinct on arbitrary bit-widths (OCamlPro/alt-ergo#1222) - Only perform optimization when building a model (OCamlPro/alt-ergo#1224) - Make sure domains do not overflow the default domain (OCamlPro/alt-ergo#1225) - Do not build unnormalized values in `zero_extend` (OCamlPro/alt-ergo#1226) ### Internal/library changes - Rewrite the Vec module (OCamlPro/alt-ergo#607) - Move printer definitions closer to type definitions (OCamlPro/alt-ergo#808) - Mark proxy names as reserved (OCamlPro/alt-ergo#836) - Use a Zarith-based representation for numbers and bit-vectors (OCamlPro/alt-ergo#850, OCamlPro/alt-ergo#943) - Add native support for (bvnot) in the BV solver (OCamlPro/alt-ergo#856) - Add constant propagators for partially interpreted functions (OCamlPro/alt-ergo#869) - Remove `Util.failwith` in favor of `Fmt.failwith` (OCamlPro/alt-ergo#872) - Add more `Expr` smart constructors (OCamlPro/alt-ergo#877, OCamlPro/alt-ergo#878) - Do not use existential variables for integer division (OCamlPro/alt-ergo#881) - Preserve `Subst` literals to prevent accidental incompleteness (OCamlPro/alt-ergo#886) - Properly start timers (OCamlPro/alt-ergo#924) - Compute a concrete representation of a model instead of performing (OCamlPro/alt-ergo#925) - Allow direct access to the SAT API in the Alt-Ergo library computations during printing (OCamlPro/alt-ergo#927) - Better handling for step limit (OCamlPro/alt-ergo#936) - Add a generic option manager to deal with the dolmen state (OCamlPro/alt-ergo#951) - Expose an imperative SAT API in the Alt-Ergo library (OCamlPro/alt-ergo#962) - Keep track of the SMT-LIB mode (OCamlPro/alt-ergo#971) - Add ability to decide on semantic literals (OCamlPro/alt-ergo#1027, OCamlPro/alt-ergo#1118) - Preserve trigger order when parsing quantifiers with multiple trigger (OCamlPro/alt-ergo#1046). - Store domains inside the union-find module (OCamlPro/alt-ergo#1119) - Remove some polymorphic hashtables (OCamlPro/alt-ergo#1219) ### Build and integration - Drop support for OCaml <4.08.1 (OCamlPro/alt-ergo#803) - Use dune-site for the inequalities plugins. External pluginsm ust now be registered through the dune-site plugin mechanism in the `(alt-ergo plugins)` site to be picked up by Alt-Ergo (OCamlPro/alt-ergo#1049). - Add a release workflow (OCamlPro/alt-ergo#827) - Add a Windows workflow (OCamlPro/alt-ergo#1203) - Mark the dune.inc file as linguist-generated to avoid huge diffs (OCamlPro/alt-ergo#830) - Use GitHub Actions badges in the README (OCamlPro/alt-ergo#882) - Use `dune build @check` to build the project (OCamlPro/alt-ergo#887) - Enable warnings as errors on the CI (OCamlPro/alt-ergo#888) - Uniformization of internal identifiers generation (OCamlPro/alt-ergo#905, OCamlPro/alt-ergo#918) - Use an efficient `String.starts_with` implementation (OCamlPro/alt-ergo#912) - Fix the Makefile (OCamlPro/alt-ergo#914) - Add `Logs` dependency (OCamlPro/alt-ergo#1206) - Use `dynamic_include` to include the generated file `dune.inc` (OCamlPro/alt-ergo#1199) - Support Windows (OCamlPro/alt-ergo#1184,OCamlPro/alt-ergo#1189,OCamlPro/alt-ergo#1195,OCamlPro/alt-ergo#1199,OCamlPro/alt-ergo#1200) - Wrap the library `Alt_ergo_prelude` (OCamlPro/alt-ergo#1223) ### Testing - Use --enable-assertions in tests (OCamlPro/alt-ergo#809) - Add a test for push/pop (OCamlPro/alt-ergo#843) - Use the CDCL solver when testing model generation (OCamlPro/alt-ergo#938) - Do not test .smt2 files with the legacy frontend (OCamlPro/alt-ergo#939) - Restore automatic creation of .expected files (OCamlPro/alt-ergo#941) ### Documentation - Add a new example for model generation (OCamlPro/alt-ergo#826) - Add a Pygments lexer for the Alt-Ergo native language (OCamlPro/alt-ergo#862) - Update the current authors (OCamlPro/alt-ergo#865) - Documentation of the `Enum` theory (OCamlPro/alt-ergo#871) - Document `Th_util.lit_origin` (OCamlPro/alt-ergo#915) - Document the CDCL-Tableaux solver (OCamlPro/alt-ergo#995) - Document Windows support (OCamlPro/alt-ergo#1216) - Remove instructions to install Alt-Ergo on Debian (OCamlPro/alt-ergo#1217) - Document optimization feature (OCamlPro/alt-ergo#1231)
CHANGES: ### Command-line interface - Enable FPA theory by default (OCamlPro/alt-ergo#1177) - Remove deprecated output channels (OCamlPro/alt-ergo#782) - Deprecate the --use-underscore since it produces models that are not SMT-LIB compliant (OCamlPro/alt-ergo#805) - Add --dump-models-on to dump models on a specific output channel (OCamlPro/alt-ergo#838) - Use consistent return codes (OCamlPro/alt-ergo#842) - Add --continue-on-error flag to set the SMT-LIB error behavior (OCamlPro/alt-ergo#853) - Make dolmen the default value for the --frontend option (OCamlPro/alt-ergo#857) - Restore functionality to broken `--profiling` option (OCamlPro/alt-ergo#947) - Add bare-bones support for interactive input in SMT-LIB format (OCamlPro/alt-ergo#949) - Less confusing behavior on timeout (OCamlPro/alt-ergo#982, OCamlPro/alt-ergo#984) - Add `--strict` option for SMT-LIB compliant mode (OCamlPro/alt-ergo#916, OCamlPro/alt-ergo#1133) - Deprecate `sum`, `typing` and `warnings` debug flags (OCamlPro/alt-ergo#1204) ### SMT-LIB support - Add support for the many new SMT-LIB commands (OCamlPro/alt-ergo#837, OCamlPro/alt-ergo#848, OCamlPro/alt-ergo#852, OCamlPro/alt-ergo#863, OCamlPro/alt-ergo#911, OCamlPro/alt-ergo#942, OCamlPro/alt-ergo#945, OCamlPro/alt-ergo#961, OCamlPro/alt-ergo#975, OCamlPro/alt-ergo#1069) - Expose the FPA rounding builtin in the SMT-LIB format (OCamlPro/alt-ergo#876, OCamlPro/alt-ergo#1135) - Allow changing the SAT solver using (set-option) (OCamlPro/alt-ergo#880) - Add support for the `:named` attribute (OCamlPro/alt-ergo#957) - Add support for quoted identifiers (OCamlPro/alt-ergo#909, OCamlPro/alt-ergo#972) - Add support for naming lemmas in SMT-LIB syntax (OCamlPro/alt-ergo#1141, OCamlPro/alt-ergo#1143) ### Model generation - Use post-solve SAT environment in model generation, fixing issues where incorrect models were generated (OCamlPro/alt-ergo#789) - Restore support for records in models (OCamlPro/alt-ergo#793) - Use abstract values instead of dummy values in models where the actual value does not matter (OCamlPro/alt-ergo#804, OCamlPro/alt-ergo#835) - Use fresh names for all abstract values to prevent accidental captures (OCamlPro/alt-ergo#811) - Add support for model generation with the default CDCL solver (OCamlPro/alt-ergo#829) - Support model generation for the BV theory (OCamlPro/alt-ergo#841, OCamlPro/alt-ergo#968) - Add support for optimization (MaxSMT / OptiSMT) with lexicographic Int and Real objectives (OCamlPro/alt-ergo#861, OCamlPro/alt-ergo#921) - Add a SMT-LIB printer for expressions (OCamlPro/alt-ergo#952, OCamlPro/alt-ergo#981, OCamlPro/alt-ergo#1082, OCamlPro/alt-ergo#931, OCamlPro/alt-ergo#932) - Ensure models have a value for all constants in the problem (OCamlPro/alt-ergo#1019) - Fix a rare soundness issue with integer constraints when model generation is enabled (OCamlPro/alt-ergo#1025) - Support model generation for the ADT theory (OCamlPro/alt-ergo#1093, OCamlPro/alt-ergo#1153) ### Theory reasoning - Add word-level propagators for the BV theory (OCamlPro/alt-ergo#944, OCamlPro/alt-ergo#1004, OCamlPro/alt-ergo#1007, OCamlPro/alt-ergo#1010, OCamlPro/alt-ergo#1011, OCamlPro/alt-ergo#1012, OCamlPro/alt-ergo#1040, OCamlPro/alt-ergo#1044, OCamlPro/alt-ergo#1054, OCamlPro/alt-ergo#1055, OCamlPro/alt-ergo#1056, OCamlPro/alt-ergo#1057, OCamlPro/alt-ergo#1065, OCamlPro/alt-ergo#1073, OCamlPro/alt-ergo#1144, OCamlPro/alt-ergo#1152) - Add interval domains and arithmetic propagators for the BV theory (OCamlPro/alt-ergo#1058, OCamlPro/alt-ergo#1083, OCamlPro/alt-ergo#1084, OCamlPro/alt-ergo#1085) - Native support for bv2nat of bit-vector normal forms (OCamlPro/alt-ergo#1154) - Fix incompleteness issues in the BV solver (OCamlPro/alt-ergo#978, OCamlPro/alt-ergo#979) - Abstract more arguments of AC symbols to avoid infinite loops when they contain other AC symbols (OCamlPro/alt-ergo#990) - Do not make irrelevant decisions in CDCL solver, improving performance slightly (OCamlPro/alt-ergo#1041) - Rewrite the ADT theory to use domains and integrate the enum theory into the ADT theory (OCamlPro/alt-ergo#1078, OCamlPro/alt-ergo#1086, OCamlPro/alt-ergo#1087, OCamlPro/alt-ergo#1091, OCamlPro/alt-ergo#1094, OCamlPro/alt-ergo#1138) - Rewrite the Intervals module entirely (OCamlPro/alt-ergo#1108) - Add maximize/minimize terms for matching (OCamlPro/alt-ergo#1166) - Internalize `sign_extend` and `repeat` (OCamlPro/alt-ergo#1192) - Run cross-propagators to completion (OCamlPro/alt-ergo#1221) - Support binary distinct on arbitrary bit-widths (OCamlPro/alt-ergo#1222) - Only perform optimization when building a model (OCamlPro/alt-ergo#1224) - Make sure domains do not overflow the default domain (OCamlPro/alt-ergo#1225) - Do not build unnormalized values in `zero_extend` (OCamlPro/alt-ergo#1226) ### Internal/library changes - Rewrite the Vec module (OCamlPro/alt-ergo#607) - Move printer definitions closer to type definitions (OCamlPro/alt-ergo#808) - Mark proxy names as reserved (OCamlPro/alt-ergo#836) - Use a Zarith-based representation for numbers and bit-vectors (OCamlPro/alt-ergo#850, OCamlPro/alt-ergo#943) - Add native support for (bvnot) in the BV solver (OCamlPro/alt-ergo#856) - Add constant propagators for partially interpreted functions (OCamlPro/alt-ergo#869) - Remove `Util.failwith` in favor of `Fmt.failwith` (OCamlPro/alt-ergo#872) - Add more `Expr` smart constructors (OCamlPro/alt-ergo#877, OCamlPro/alt-ergo#878) - Do not use existential variables for integer division (OCamlPro/alt-ergo#881) - Preserve `Subst` literals to prevent accidental incompleteness (OCamlPro/alt-ergo#886) - Properly start timers (OCamlPro/alt-ergo#924) - Compute a concrete representation of a model instead of performing (OCamlPro/alt-ergo#925) - Allow direct access to the SAT API in the Alt-Ergo library computations during printing (OCamlPro/alt-ergo#927) - Better handling for step limit (OCamlPro/alt-ergo#936) - Add a generic option manager to deal with the dolmen state (OCamlPro/alt-ergo#951) - Expose an imperative SAT API in the Alt-Ergo library (OCamlPro/alt-ergo#962) - Keep track of the SMT-LIB mode (OCamlPro/alt-ergo#971) - Add ability to decide on semantic literals (OCamlPro/alt-ergo#1027, OCamlPro/alt-ergo#1118) - Preserve trigger order when parsing quantifiers with multiple trigger (OCamlPro/alt-ergo#1046). - Store domains inside the union-find module (OCamlPro/alt-ergo#1119) - Remove some polymorphic hashtables (OCamlPro/alt-ergo#1219) ### Build and integration - Drop support for OCaml <4.08.1 (OCamlPro/alt-ergo#803) - Use dune-site for the inequalities plugins. External pluginsm ust now be registered through the dune-site plugin mechanism in the `(alt-ergo plugins)` site to be picked up by Alt-Ergo (OCamlPro/alt-ergo#1049). - Add a release workflow (OCamlPro/alt-ergo#827) - Add a Windows workflow (OCamlPro/alt-ergo#1203) - Mark the dune.inc file as linguist-generated to avoid huge diffs (OCamlPro/alt-ergo#830) - Use GitHub Actions badges in the README (OCamlPro/alt-ergo#882) - Use `dune build @check` to build the project (OCamlPro/alt-ergo#887) - Enable warnings as errors on the CI (OCamlPro/alt-ergo#888) - Uniformization of internal identifiers generation (OCamlPro/alt-ergo#905, OCamlPro/alt-ergo#918) - Use an efficient `String.starts_with` implementation (OCamlPro/alt-ergo#912) - Fix the Makefile (OCamlPro/alt-ergo#914) - Add `Logs` dependency (OCamlPro/alt-ergo#1206) - Use `dynamic_include` to include the generated file `dune.inc` (OCamlPro/alt-ergo#1199) - Support Windows (OCamlPro/alt-ergo#1184,OCamlPro/alt-ergo#1189,OCamlPro/alt-ergo#1195,OCamlPro/alt-ergo#1199,OCamlPro/alt-ergo#1200) - Wrap the library `Alt_ergo_prelude` (OCamlPro/alt-ergo#1223) ### Testing - Use --enable-assertions in tests (OCamlPro/alt-ergo#809) - Add a test for push/pop (OCamlPro/alt-ergo#843) - Use the CDCL solver when testing model generation (OCamlPro/alt-ergo#938) - Do not test .smt2 files with the legacy frontend (OCamlPro/alt-ergo#939) - Restore automatic creation of .expected files (OCamlPro/alt-ergo#941) ### Documentation - Add a new example for model generation (OCamlPro/alt-ergo#826) - Add a Pygments lexer for the Alt-Ergo native language (OCamlPro/alt-ergo#862) - Update the current authors (OCamlPro/alt-ergo#865) - Documentation of the `Enum` theory (OCamlPro/alt-ergo#871) - Document `Th_util.lit_origin` (OCamlPro/alt-ergo#915) - Document the CDCL-Tableaux solver (OCamlPro/alt-ergo#995) - Document Windows support (OCamlPro/alt-ergo#1216) - Remove instructions to install Alt-Ergo on Debian (OCamlPro/alt-ergo#1217) - Document optimization feature (OCamlPro/alt-ergo#1231)
This patch changes the way that bit-vector domains are stored in order to share domains between multiple bit-vectors with the same variable part, including across different bit-width. Currently, if we had terms [x], [00 @ x], and [10 @ x], we would store domains for each of these. With this patch, we only store a domain for [x] and rebuild the domains for [00 @ x] and [10 @ x] dynamically; we do this by computing normal forms composed of a variable part ([x] here) and a constant offset (either [0] or [10]).
This reduces the number of variables handled by the system (which is important for global domains such as global difference) and reduces the number of trivial propagations.
Note that this patch is not reverting #1044. In particular, we are considering [x @ y] as a unique (composite) variable built up from the atomic variables [x] and [y] (in the same way that the polynomial [x + y] is built up from the monomial [x] and [y] in the IntervalCalculus module; in fact, the implementation is intentionally abstracted in order to be useable with polynomials). This is necessary because, as noted in #1044, the interval domain for [x @ y] cannot be built reconstructed precisely from the interval domains for [x] and [y].
The patch includes a bit of refactoring of the way we handle constraints; notably, instead of aggressively substituting constraints, we now store the original constraint and call [Uf.find] at propagation time. This avoids having to define a substitution operation on normal forms and allows storing the constraint dependencies directly inside the domain (in the previous design, we could not do it easily without repeating the expensive substitution of constraint arguments).
Note: depends on #1144. Only the latest commit with title "feat(BV): Interval domains for bit-vectors" is included in this PR.
Benchmarks: This PR provides a small reasoning boost (+171-48 on the usual QF_BV subset) and a significant performance boost for bit-vector reasoning (-25% on the same QF_BV subset) compared to #1144.