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Cost: simplify range of parameters

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Reviewed By: ddino

Differential Revision: D8379528

fbshipit-source-id: cf7da17
master
Mehdi Bouaziz 7 years ago committed by Facebook Github Bot
parent bea71d9168
commit e5de1b6663
4 changed files with 123 additions and 87 deletions
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44
infer/src/bufferoverrun/itv.ml
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@ -97,6 +97,8 @@ module Symbol = struct
let equal = [%compare.equal : t]
let paths_equal s1 s2 = phys_equal s1.path s2.path
let make : unsigned:bool -> Typ.Procname.t -> SymbolPath.t -> BoundEnd.t -> int -> t =
fun ~unsigned pname path bound_end id -> {id; pname; unsigned; path; bound_end}
@ -165,6 +167,10 @@ module NonZeroInt : sig
val plus : t -> t -> t option
val exact_div_exn : t -> t -> t
val max : t -> t -> t
val min : t -> t -> t
end = struct
type t = int [@@deriving compare]
@ -197,6 +203,11 @@ end = struct
let exact_div_exn num den =
if not (is_multiple num den) then raise DivisionNotExact ;
num / den
let max = Int.max
let min = Int.min
end
module Ints : sig
@ -419,6 +430,28 @@ module SymLinear = struct
let int_lb x = if is_ge_zero x then Some 0 else None
let int_ub x = if is_le_zero x then Some 0 else None
(** When two following symbols are from the same path, simplify what would lead to a zero sum. E.g. 2 * x.lb - x.ub = x.lb *)
let simplify_bound_ends_from_paths : t -> t =
fun x ->
let f (prev_opt, to_add) symb coeff =
match prev_opt with
| Some (prev_coeff, prev_symb)
when Symbol.paths_equal prev_symb symb
&& NonZeroInt.is_positive coeff <> NonZeroInt.is_positive prev_coeff ->
let add_coeff =
(if NonZeroInt.is_positive coeff then NonZeroInt.max else NonZeroInt.min)
prev_coeff (NonZeroInt.( ~- ) coeff)
in
let to_add =
to_add |> M.add symb add_coeff |> M.add prev_symb (NonZeroInt.( ~- ) add_coeff)
in
(None, to_add)
| _ ->
(Some (coeff, symb), to_add)
in
let _, to_add = fold x ~init:(None, zero) ~f in
plus x to_add
end
module Bound = struct
@ -1030,6 +1063,14 @@ module Bound = struct
let subst_lb_exn x map = subst_exn ~subst_pos:BoundEnd.LowerBound x map
let subst_ub_exn x map = subst_exn ~subst_pos:BoundEnd.UpperBound x map
let simplify_bound_ends_from_paths x =
match x with
| MInf | PInf | MinMax _ ->
x
| Linear (c, se) ->
let se' = SymLinear.simplify_bound_ends_from_paths se in
if phys_equal se se' then x else Linear (c, se')
end
type ('c, 's) valclass = Constant of 'c | Symbolic of 's | ValTop
@ -1393,7 +1434,8 @@ module ItvRange = struct
let of_bounds : lb:Bound.t -> ub:Bound.t -> t =
fun ~lb ~ub ->
Bound.plus_u ub Bound.one |> Bound.plus_u (Bound.neg lb) |> NonNegativeBound.of_bound
Bound.plus_u ub Bound.one |> Bound.plus_u (Bound.neg lb)
|> Bound.simplify_bound_ends_from_paths |> NonNegativeBound.of_bound
let to_top_lifted_polynomial : t -> NonNegativePolynomial.astate =

3
infer/tests/codetoanalyze/c/performance/issues.exp
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@ -42,9 +42,6 @@ codetoanalyze/c/performance/cost_test.c, loop1_bad, 6, EXPENSIVE_EXECUTION_TIME_
codetoanalyze/c/performance/cost_test.c, loop2_bad, 2, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 3 + 11 * k.ub]
codetoanalyze/c/performance/cost_test.c, loop2_bad, 3, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 3 + 11 * k.ub]
codetoanalyze/c/performance/cost_test.c, loop2_bad, 5, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 5 + 11 * k.ub]
codetoanalyze/c/performance/cost_test.c, loop3_bad, 2, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 4 + 11 * (-k.lb + k.ub + 15)]
codetoanalyze/c/performance/cost_test.c, loop3_bad, 3, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 4 + 11 * (-k.lb + k.ub + 15)]
codetoanalyze/c/performance/cost_test.c, loop3_bad, 5, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 6 + 11 * (-k.lb + k.ub + 15)]
codetoanalyze/c/performance/cost_test.c, main_bad, 8, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 211]
codetoanalyze/c/performance/cost_test.c, while_upto20_bad, 1, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 1 + 5 * (-m.lb + 20)]
codetoanalyze/c/performance/cost_test.c, while_upto20_bad, 2, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 1 + 5 * (-m.lb + 20)]

159
infer/tests/codetoanalyze/java/performance/Cost_test.java
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@ -7,116 +7,113 @@
package codetoanalyze.java.performance;
public class Cost_test{
public class Cost_test {
// Cost: 5
private static int foo_OK() {
int i, j;
i = 17;
j = 31;
// Cost: 5
private static int foo_OK() {
int i, j;
i = 17;
j = 31;
return i + j + 3 + 7;
}
return i + j + 3 + 7;
}
// Cost: 17
private static int bar_OK() {
// Cost: 17
private static int bar_OK() {
int j = 0;
int j = 0;
j++;
j++;
j++;
j = foo_OK();
j++;
j++;
j++;
j++;
j = foo_OK();
j++;
return j;
}
return j;
}
// Cost: 25
private static int cond_OK(int i) {
int x;
// Cost: 25
private static int cond_OK(int i) {
int x;
if (i < 0) {
x = bar_OK();
} else {
x = 1;
if (i < 0) {
x = bar_OK();
} else {
x = 1;
}
return x;
}
return x;
}
// Cost: 5
private static void alias_OK() {
// Cost: 5
private static void alias_OK() {
int i = 0, j;
int i = 0, j;
j = i;
i = ++i;
}
// Cost: 7
private static void alias2_OK() {
j = i;
i = ++i;
}
int i = 0, j, z;
// Cost: 7
private static void alias2_OK() {
j = 1;
z = 2;
int i = 0, j, z;
j = i;
i = z;
}
j = 1;
z = 2;
// Cost: 1101
private static int loop0_bad() {
for (int i = 0; i < 100; i++) {
alias2_OK();
j = i;
i = z;
}
return 0;
}
// Cost: 1203
private static int loop1_bad() {
// Cost: 1101
private static int loop0_bad() {
int k = 100;
for (int i = 0; i < k; i++) {
alias2_OK();
for (int i = 0; i < 100; i++) {
alias2_OK();
}
return 0;
}
return 0;
}
// Expected: Linear bound
private static int FN_loop2(int k) {
// Cost: 1203
private static int loop1_bad() {
for (int i = 0; i < k; i++) {
alias2_OK();
int k = 100;
for (int i = 0; i < k; i++) {
alias2_OK();
}
return 0;
}
return 0;
}
// Expected: constant, but the bound is a polynomial since we can't
// currently map variables to polynomial symbols
private static int FN_loop3(int k) {
// Expected: Linear bound
private static int FN_loop2(int k) {
for (int i = k; i < k + 15; i++) {
alias2_OK();
for (int i = 0; i < k; i++) {
alias2_OK();
}
return 0;
}
return 0;
}
// Cost: 218
// Shows that calling many times non expensive function can
// result in an expensive computation
private static int main_bad() {
// Expected: constant
private static int loop3(int k) {
int k1, k2, k3, k4;
for (int i = k; i < k + 18; i++) {
alias2_OK();
}
return 0;
}
cond_OK(2);
k1 = bar_OK() + foo_OK() + cond_OK(15) * 2;
k2 = bar_OK() + foo_OK() + cond_OK(17) * 3;
k3 = bar_OK() + foo_OK() + cond_OK(11) * 3;
k4 = bar_OK() + foo_OK() + cond_OK(19) * 3;
return 0;
}
// Cost: 218
// Shows that calling many times non expensive function can
// result in an expensive computation
private static int main_bad() {
int k1, k2, k3, k4;
cond_OK(2);
k1 = bar_OK() + foo_OK() + cond_OK(15) * 2;
k2 = bar_OK() + foo_OK() + cond_OK(17) * 3;
k3 = bar_OK() + foo_OK() + cond_OK(11) * 3;
k4 = bar_OK() + foo_OK() + cond_OK(19) * 3;
return 0;
}
}

4
infer/tests/codetoanalyze/java/performance/issues.exp
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@ -20,12 +20,12 @@ codetoanalyze/java/performance/Compound_loop.java, void Compound_loop.while_and_
codetoanalyze/java/performance/Continue.java, int Continue.continue_outer_loop_FN(), 0, INFINITE_EXECUTION_TIME_CALL, no_bucket, ERROR, []
codetoanalyze/java/performance/Cost_test.java, int Cost_test.FN_loop2(int), 2, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 2 + 12 * k.ub]
codetoanalyze/java/performance/Cost_test.java, int Cost_test.FN_loop2(int), 2, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 1 + 12 * k.ub]
codetoanalyze/java/performance/Cost_test.java, int Cost_test.FN_loop3(int), 2, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 3 + 12 * (-k.lb + k.ub + 15)]
codetoanalyze/java/performance/Cost_test.java, int Cost_test.FN_loop3(int), 2, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 2 + 12 * (-k.lb + k.ub + 15)]
codetoanalyze/java/performance/Cost_test.java, int Cost_test.loop0_bad(), 2, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 1101]
codetoanalyze/java/performance/Cost_test.java, int Cost_test.loop0_bad(), 2, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 1102]
codetoanalyze/java/performance/Cost_test.java, int Cost_test.loop1_bad(), 3, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 1203]
codetoanalyze/java/performance/Cost_test.java, int Cost_test.loop1_bad(), 3, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 1202]
codetoanalyze/java/performance/Cost_test.java, int Cost_test.loop3(int), 2, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 219]
codetoanalyze/java/performance/Cost_test.java, int Cost_test.loop3(int), 2, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 218]
codetoanalyze/java/performance/Cost_test.java, int Cost_test.main_bad(), 8, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 237]
codetoanalyze/java/performance/Cost_test.java, int Cost_test.main_bad(), 8, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 205]
codetoanalyze/java/performance/Cost_test.java, int Cost_test.main_bad(), 9, EXPENSIVE_EXECUTION_TIME_CALL, no_bucket, ERROR, [with estimated cost 243]

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