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| author | Xavier Leroy <xavierleroy@users.noreply.github.com> | 2021-11-16 09:38:54 +0100 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2021-11-16 09:38:54 +0100 |
| commit | b9dfe18fb99d9fd0e8918c160ee297755c5fca59 (patch) | |
| tree | c7613e597e7f13156b57cdaf97c0ec89a4b7f655 /common | |
| parent | 168495d726e623e0b4bd6364f949ae577fa8b52e (diff) | |
| download | compcert-kvx-b9dfe18fb99d9fd0e8918c160ee297755c5fca59.tar.gz compcert-kvx-b9dfe18fb99d9fd0e8918c160ee297755c5fca59.zip | |
An improved PTree data structure (#420)
This PR replaces the "PTree" data structure used in lib/Maps.v by the
canonical binary tries data structure proposed by A. W. Appel and
described in the paper "Efficient Extensional Binary Tries",
https://arxiv.org/abs/2110.05063
The new implementation is more memory-efficient and a bit faster,
resulting in reduced compilation times (-5% on typical C programs, up
to -10% on very large C functions).
It also enjoys the extensionality property (two tries mapping equal
keys to equal data are equal), which simplifies some proofs.
Diffstat (limited to 'common')
| -rw-r--r-- | common/Globalenvs.v | 9 | ||||
| -rw-r--r-- | common/Memory.v | 11 |
2 files changed, 1 insertions, 19 deletions
diff --git a/common/Globalenvs.v b/common/Globalenvs.v index 4c9e7889..f424a69d 100644 --- a/common/Globalenvs.v +++ b/common/Globalenvs.v @@ -265,15 +265,6 @@ Qed. Program Definition empty_genv (pub: list ident): t := @mkgenv pub (PTree.empty _) (PTree.empty _) 1%positive _ _ _. -Next Obligation. - rewrite PTree.gempty in H. discriminate. -Qed. -Next Obligation. - rewrite PTree.gempty in H. discriminate. -Qed. -Next Obligation. - rewrite PTree.gempty in H. discriminate. -Qed. Definition globalenv (p: program F V) := add_globals (empty_genv p.(prog_public)) p.(prog_defs). diff --git a/common/Memory.v b/common/Memory.v index fa60455b..03a6572e 100644 --- a/common/Memory.v +++ b/common/Memory.v @@ -346,15 +346,6 @@ Program Definition empty: mem := mkmem (PMap.init (ZMap.init Undef)) (PMap.init (fun ofs k => None)) 1%positive _ _ _. -Next Obligation. - repeat rewrite PMap.gi. red; auto. -Qed. -Next Obligation. - rewrite PMap.gi. auto. -Qed. -Next Obligation. - rewrite PMap.gi. auto. -Qed. (** Allocation of a fresh block with the given bounds. Return an updated memory state and the address of the fresh block, which initially contains @@ -631,7 +622,7 @@ Proof. reflexivity. Qed. Theorem perm_empty: forall b ofs k p, ~perm empty b ofs k p. Proof. - intros. unfold perm, empty; simpl. rewrite PMap.gi. simpl. tauto. + intros. unfold perm, empty; simpl. tauto. Qed. Theorem valid_access_empty: forall chunk b ofs p, ~valid_access empty chunk b ofs p. |