A CIL Tutorial - Department of Computer Science - ETH Zürich

CHAPTER 11. PROGRAM VERIFICATION 95
The functions term of apuop and term of apbop translate AUnOp and ABinOp attribute parameters
into Why3 terms.
and term of apuop (wc : wctxt) (u : unop) (ap : attrparam) : T.term =
let te = term of attrparam wc ap in
match u with
| Neg → T.t app infer wc.ops.iminus op [(term of int 0); te]
| LNot → T.t equ te (term of int 0)
| BNot → Em.s (Em.unimp "Attribute BNot: £%a\n" d attrparam ap)
and term of apbop (wc : wctxt) (b : binop) (ap1 : attrparam) (ap2 : attrparam) : T.term =
let te1 = term of attrparam wc ap1 in
let te2 = term of attrparam wc ap2 in
match b with
| PlusA | PlusPI | IndexPI → T.t app infer wc.ops.iplus op [te1; te2]
| MinusA | MinusPI | MinusPP → T.t app infer wc.ops.iminus op [te1; te2]
(∗ ... ∗)
| → Em.s (Em.error "term of bop failed: %a %a %a\n"
d attrparam ap1 d binop b d attrparam ap2)
The function term of star translates a memory referene in an attribute parameter into a Why3
get operation of the address in the memory map of the Why3 context.
and term of star (wc : wctxt) (a : attrparam) : T.term =
let at = term of attrparam wc a in
let mt = T.t var wc.memory in
T.t app infer wc.ops.get op [mt; at]
The function term of index is similar to term of star. First, though, we have to calculate the
address by adding the index to the base pointer.
and term of index (wc : wctxt) (base : attrparam) (index : attrparam) : T.term =
let bt = term of attrparam wc base in
let it = term of attrparam wc index in
let addr = T.t app infer wc.ops.iplus op [bt; it] in
let mt = T.t var wc.memory in
T.t app infer wc.ops.get op [mt; addr]
The function oldvar of ap nds the Why3 symbol for a variable in the context.
let oldvar of ap (wc : wctxt) (ap : attrparam) : T.vsymbol =
match ap with
| ACons(n, [ ]) → SM.find n wc.vars
| → Em.s(Em.error "Names only")