1. 25 Oct, 2016 2 commits
    • Robbert Krebbers's avatar
      Rename uPred_eq into uPred_internal_eq. · e224e891
      Robbert Krebbers authored
      e224e891
    • Robbert Krebbers's avatar
      Generalize update tactics into iMod and iModIntro for modalities. · fc30ca08
      Robbert Krebbers authored
      There are now two proof mode tactics for dealing with modalities:
      
      - `iModIntro` : introduction of a modality
      - `iMod pm_trm as (x1 ... xn) "ipat"` : eliminate a modality
      
      The behavior of these tactics can be controlled by instances of the `IntroModal`
      and `ElimModal` type class. We have declared instances for later, except 0,
      basic updates and fancy updates. The tactic `iMod` is flexible enough that it
      can also eliminate an updates around a weakest pre, and so forth.
      
      The corresponding introduction patterns of these tactics are `!>` and `>`.
      
      These tactics replace the tactics `iUpdIntro`, `iUpd` and `iTimeless`.
      
      Source of backwards incompatability: the introduction pattern `!>` is used for
      introduction of arbitrary modalities. It used to introduce laters by stripping
      of a later of each hypotheses.
      fc30ca08
  2. 05 Oct, 2016 1 commit
  3. 19 Sep, 2016 1 commit
  4. 09 Sep, 2016 1 commit
    • Robbert Krebbers's avatar
      Support for specialization of P₁ -★ .. -★ Pₙ -★ Q where Q is persistent. · 090aaea3
      Robbert Krebbers authored
      Before this commit, given "HP" : P and "H" : P -★ Q with Q persistent, one
      could write:
      
        iSpecialize ("H" with "#HP")
      
      to eliminate the wand in "H" while keeping the resource "HP". The lemma:
      
        own_valid : own γ x ⊢ ✓ x
      
      was the prototypical example where this pattern (using the #) was used.
      
      However, the pattern was too limited. For example, given "H" : P₁ -★ P₂ -★ Q",
      one could not write iSpecialize ("H" with "#HP₁") because P₂ -★ Q is not
      persistent, even when Q is.
      
      So, instead, this commit introduces the following tactic:
      
        iSpecialize pm_trm as #
      
      which allows one to eliminate implications and wands while being able to use
      all hypotheses to prove the premises, as well as being able to use all
      hypotheses to prove the resulting goal.
      
      In the case of iDestruct, we now check whether all branches of the introduction
      pattern start with an `#` (moving the hypothesis to the persistent context) or
      `%` (moving the hypothesis to the pure Coq context). If this is the case, we
      allow one to use all hypotheses for proving the premises, as well as for proving
      the resulting goal.
      090aaea3
  5. 24 Aug, 2016 1 commit
  6. 05 Aug, 2016 2 commits
    • Robbert Krebbers's avatar
      More introduction patterns. · 4d8c4ac8
      Robbert Krebbers authored
      Also make those for introduction and elimination more symmetric:
      
        !%   pure introduction         %        pure elimination
        !#   always introduction       #        always elimination
        !>   later introduction        > pat    timeless later elimination
        !==> view shift introduction   ==> pat  view shift elimination
      4d8c4ac8
    • Robbert Krebbers's avatar
      Iris 3.0: invariants and weakest preconditions encoded in the logic. · 1f589858
      Robbert Krebbers authored
      This commit features:
      
      - A simpler model. The recursive domain equation no longer involves a triple
        containing invariants, physical state and ghost state, but just ghost state.
        Invariants and physical state are encoded using (higher-order) ghost state.
      
      - (Primitive) view shifts are formalized in the logic and all properties about
        it are proven in the logic instead of the model. Instead, the core logic
        features only a notion of raw view shifts which internalizing performing frame
        preserving updates.
      
      - A better behaved notion of mask changing view shifts. In particular, we no
        longer have side-conditions on transitivity of view shifts, and we have a
        rule for introduction of mask changing view shifts |={E1,E2}=> P with
        E2 ⊆ E1 which allows to postpone performing a view shift.
      
      - The weakest precondition connective is formalized in the logic using Banach's
        fixpoint. All properties about the connective are proven in the logic instead
        of directly in the model.
      
      - Adequacy is proven in the logic and uses a primitive form of adequacy for
        uPred that only involves raw views shifts and laters.
      
      Some remarks:
      
      - I have removed binary view shifts. I did not see a way to describe all rules
        of the new mask changing view shifts using those.
      - There is no longer the need for the notion of "frame shifting assertions" and
        these are thus removed. The rules for Hoare triples are thus also stated in
        terms of primitive view shifts.
      
      TODO:
      
      - Maybe rename primitive view shift into something more sensible
      - Figure out a way to deal with closed proofs (see the commented out stuff in
        tests/heap_lang and tests/barrier_client).
      1f589858
  7. 27 Jul, 2016 1 commit
  8. 26 Jul, 2016 1 commit
  9. 13 Jul, 2016 1 commit
  10. 30 Jun, 2016 3 commits
  11. 17 Jun, 2016 1 commit
  12. 01 Jun, 2016 1 commit
  13. 31 May, 2016 2 commits
  14. 30 May, 2016 1 commit
  15. 27 May, 2016 1 commit
  16. 24 May, 2016 3 commits
    • Robbert Krebbers's avatar
      Merge iAssert and iPvsAssert. · e965b669
      Robbert Krebbers authored
      To do so, we have introduced the specialization patterns:
      
        =>[H1 .. Hn] and =>[-H1 .. Hn]
      
      That generate a goal in which the view shift is preserved. These specialization
      patterns can also be used for e.g. iApply.
      
      Note that this machinery is not tied to primitive view shifts, and works for
      various kinds of goal (as captured by the ToAssert type class, which describes
      how to transform the asserted goal based on the main goal).
      
      TODO: change the name of these specialization patterns to reflect this
      generality.
      e965b669
    • Robbert Krebbers's avatar
      eacb1c46
    • Robbert Krebbers's avatar
      Make specialization patterns for persistent premises more uniform. · 65bfa071
      Robbert Krebbers authored
      Changes:
      - We no longer have a different syntax for specializing a term H : P -★ Q whose
        range P or domain Q is persistent. There is just one syntax, and the system
        automatically determines whether either P or Q is persistent.
      - While specializing a term, always modalities are automatically stripped. This
        gets rid of the specialization pattern !.
      - Make the syntax of specialization patterns more consistent. The syntax for
        generating a goal is [goal_spec] where goal_spec is one of the following:
      
          H1 .. Hn : generate a goal using hypotheses H1 .. Hn
         -H1 .. Hn : generate a goal using all hypotheses but H1 .. Hn
                 # : generate a goal for the premise in which all hypotheses can be
                     used. This is only allowed when specializing H : P -★ Q where
                     either P or Q is persistent.
                 % : generate a goal for a pure premise.
      65bfa071
  17. 21 May, 2016 1 commit
  18. 06 May, 2016 1 commit
  19. 02 May, 2016 3 commits
  20. 27 Apr, 2016 1 commit
  21. 25 Apr, 2016 1 commit
  22. 20 Apr, 2016 2 commits
    • Robbert Krebbers's avatar
      Tweak test file. · 8ca2bf37
      Robbert Krebbers authored
      8ca2bf37
    • Robbert Krebbers's avatar
      Improve iFrame tactic · 43d45c6b
      Robbert Krebbers authored
      - It can now also frame under later.
      - Better treatment of evars, it now won't end up in loops whenever the goal
        involves sub-formulas ?P and it trying to apply all framing rules eagerly.
      - It no longer delta expands while framing.
      - Better clean up of True sub-formulas after a successful frame. For example,
        framing "P" in "▷ ▷ P ★ Q" yields just "Q" instead of "▷ True ★ Q" or so.
      43d45c6b
  23. 11 Apr, 2016 1 commit