1. 31 Oct, 2018 40 commits
    • Robbert Krebbers's avatar
    • Robbert Krebbers's avatar
    • Robbert Krebbers's avatar
      f7af5b3f
    • Robbert Krebbers's avatar
      Fine-grained post-conditions for forked-off threads. · ebf06f91
      Robbert Krebbers authored
      This commit extends the state interpretation with an additional parameter to
      talk about the number of forked-off threads, and a fixed postcondition for each
      forked-off thread:
      
          state_interp : Λstate → list Λobservation → nat → iProp Σ;
          fork_post : iProp Σ;
      
      This way, instead of having `True` as the post-condition of `Fork`, one can
      have any post-condition, which is then recorded in the state interpretation.
      The point of keeping track of the postconditions of forked-off threads, is that
      we get an (additional) stronger adequacy theorem:
      
          Theorem wp_strong_all_adequacy Σ Λ `{invPreG Σ} s e σ1 v vs σ2 φ :
             (∀ `{Hinv : invG Σ} κs,
               (|={⊤}=> ∃
                   (stateI : state Λ → list (observation Λ) → nat → iProp Σ)
                   (fork_post : iProp Σ),
                 let _ : irisG Λ Σ := IrisG _ _ _ Hinv stateI fork_post in
                 stateI σ1 κs 0 ∗ WP e @ s; ⊤ {{ v,
                   let m := length vs in
                   stateI σ2 [] m -∗ [∗] replicate m fork_post ={⊤,∅}=∗ ⌜ φ v ⌝ }})%I) →
            rtc erased_step ([e], σ1) (of_val <$> v :: vs, σ2) →
            φ v.
      
      The difference with the ordinary adequacy theorem is that this one only applies
      once all threads terminated. In this case, one gets back the post-conditions
      `[∗] replicate m fork_post` of all forked-off threads.
      
      In Iron we showed that we can use this mechanism to make sure that all
      resources are disposed of properly in the presence of fork-based concurrency.
      ebf06f91
  2. 18 Oct, 2018 40 commits
  3. 05 Oct, 2018 40 commits
  4. 14 Jun, 2018 40 commits
  5. 24 May, 2018 40 commits
  6. 07 Dec, 2017 40 commits
  7. 26 Nov, 2017 40 commits
  8. 23 Nov, 2017 40 commits
  9. 09 Nov, 2017 40 commits
  10. 08 Nov, 2017 40 commits
  11. 25 Sep, 2017 40 commits
  12. 24 Mar, 2017 40 commits
    • Robbert Krebbers's avatar
      Generic big operators that are no longer tied to CMRAs. · 6fbff46e
      Robbert Krebbers authored
      Instead, I have introduced a type class `Monoid` that is used by the big operators:
      
          Class Monoid {M : ofeT} (o : M → M → M) := {
            monoid_unit : M;
            monoid_ne : NonExpansive2 o;
            monoid_assoc : Assoc (≡) o;
            monoid_comm : Comm (≡) o;
            monoid_left_id : LeftId (≡) monoid_unit o;
            monoid_right_id : RightId (≡) monoid_unit o;
          }.
      
      Note that the operation is an argument because we want to have multiple monoids over
      the same type (for example, on `uPred`s we have monoids for `∗`, `∧`, and `∨`). However,
      we do bundle the unit because:
      
      - If we would not, the unit would appear explicitly in an implicit argument of the
        big operators, which confuses rewrite. By bundling the unit in the `Monoid` class
        it is hidden, and hence rewrite won't even see it.
      - The unit is unique.
      
      We could in principle have big ops over setoids instead of OFEs. However, since we do
      not have a canonical structure for bundled setoids, I did not go that way.
      6fbff46e
  13. 15 Mar, 2017 40 commits
  14. 09 Mar, 2017 40 commits
  15. 05 Jan, 2017 40 commits
  16. 04 Jan, 2017 40 commits
  17. 03 Jan, 2017 40 commits
  18. 09 Dec, 2016 40 commits
    • Ralf Jung's avatar
      move everything to subfolder theories/ · 6b8069fa
      Ralf Jung authored
      6b8069fa
    • Robbert Krebbers's avatar
      Invariants over states in WP and get rid of heap_ctx. · fd89aa52
      Robbert Krebbers authored
      The WP construction now takes an invariant on states as a parameter
      (part of the irisG class) and no longer builds in the authoritative
      ownership of the entire state. When instantiating WP with a concrete
      language on can choose its state invariant. For example, for heap_lang
      we directly use `auth (gmap loc (frac * dec_agree val))`, and avoid
      the indirection through invariants entirely.
      
      As a result, we no longer have to carry `heap_ctx` around.
      fd89aa52
  19. 08 Dec, 2016 40 commits
  20. 06 Dec, 2016 40 commits
  21. 22 Nov, 2016 40 commits
  22. 03 Nov, 2016 40 commits
    • Robbert Krebbers's avatar
      Use symbol ∗ for separating conjunction. · cc31476d
      Robbert Krebbers authored
      The old choice for ★ was a arbitrary: the precedence of the ASCII asterisk *
      was fixed at a wrong level in Coq, so we had to pick another symbol. The ★ was
      a random choice from a unicode chart.
      
      The new symbol ∗ (as proposed by David Swasey) corresponds better to
      conventional practise and matches the symbol we use on paper.
      cc31476d
  23. 01 Nov, 2016 40 commits
  24. 28 Oct, 2016 40 commits