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| author | David Monniaux <david.monniaux@univ-grenoble-alpes.fr> | 2021-06-16 11:39:25 +0200 |
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| committer | David Monniaux <david.monniaux@univ-grenoble-alpes.fr> | 2021-06-16 11:39:25 +0200 |
| commit | 04b2489d7c2a9b0d203b3d431517367a07bd6b30 (patch) | |
| tree | c004620824fa5c165b5d4a8e8d681e6dc3f272e8 /kvx/Asmvliw.v | |
| parent | 8c7a5100478611c8278ccef5e06951c831d07ad8 (diff) | |
| download | compcert-kvx-04b2489d7c2a9b0d203b3d431517367a07bd6b30.tar.gz compcert-kvx-04b2489d7c2a9b0d203b3d431517367a07bd6b30.zip | |
fix modeling issue (Vundef for load outside of bounds)
Diffstat (limited to 'kvx/Asmvliw.v')
| -rw-r--r-- | kvx/Asmvliw.v | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/kvx/Asmvliw.v b/kvx/Asmvliw.v index aa2e0885..304e45a8 100644 --- a/kvx/Asmvliw.v +++ b/kvx/Asmvliw.v @@ -313,7 +313,12 @@ Inductive cf_instruction : Type := . (** *** Loads *) -Definition concrete_default_notrap_load_value (chunk : memory_chunk) := +Definition concrete_default_notrap_load_value (chunk : memory_chunk) := Vundef. + +(* What follows was the original spec, but is subtly incorrect. + Our definition of the assembly-level memory model is already an abstraction of the real world. + In particular, we consider that a load is incorrect when it points outside of CompCert's visible memory, whereas this memory could be correct at the assembly level. + This means that CompCert would believe an incorrect load would yield 0 whereas it would yield another value. match chunk with | Mint8signed | Mint8unsigned | Mint16signed | Mint16unsigned | Mint32 => Vint Int.zero @@ -321,7 +326,7 @@ Definition concrete_default_notrap_load_value (chunk : memory_chunk) := | Many32 | Many64 => Vundef | Mfloat32 => Vsingle Float32.zero | Mfloat64 => Vfloat Float.zero - end. + end. *) Inductive load_name : Type := | Plb (**r load byte *) |