From 2679bb0b61d367b93a21c8ec1d9ff1c5663b3a6b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ezgi=20=C3=87i=C3=A7ek?= Date: Tue, 20 Oct 2020 05:07:27 -0700 Subject: [PATCH] [inferbo] Add model for `String.valueOf(char[])` Reviewed By: skcho Differential Revision: D24396467 fbshipit-source-id: 0ddd7b727 --- .../src/bufferoverrun/bufferOverrunModels.ml | 41 +++++++++++++------ .../java/performance/StringTest.java | 11 +++++ .../java/performance/cost-issues.exp | 2 + 3 files changed, 42 insertions(+), 12 deletions(-) diff --git a/infer/src/bufferoverrun/bufferOverrunModels.ml b/infer/src/bufferoverrun/bufferOverrunModels.ml index f63eead77..20372445d 100644 --- a/infer/src/bufferoverrun/bufferOverrunModels.ml +++ b/infer/src/bufferoverrun/bufferOverrunModels.ml @@ -1395,11 +1395,7 @@ module JavaString = struct {exec; check= no_check} - let create_with_length {pname; node_hash; location; integer_type_widths} ~ret:(id, _) ~begin_idx - ~end_v mem = - let begin_itv = Sem.eval integer_type_widths begin_idx mem |> Dom.Val.get_itv in - let end_itv = Dom.Val.get_itv end_v in - let length_itv = Itv.minus end_itv begin_itv in + let create_with_length {pname; node_hash; location} ~ret:(id, _) ~length_itv mem = let arr_loc = Allocsite.make pname ~node_hash ~inst_num:0 ~dimension:1 ~path:None ~represents_multiple_values:false @@ -1416,17 +1412,34 @@ module JavaString = struct let substring_no_end exp begin_idx = - let exec model_env ~ret mem = - create_with_length model_env ~ret ~begin_idx ~end_v:(get_length model_env exp mem) mem + let exec ({integer_type_widths} as model_env) ~ret mem = + let begin_itv = Sem.eval integer_type_widths begin_idx mem |> Dom.Val.get_itv in + let end_itv = get_length model_env exp mem |> Dom.Val.get_itv in + let length_itv = Itv.minus end_itv begin_itv in + create_with_length model_env ~ret ~length_itv mem in {exec; check= no_check} let substring begin_idx end_idx = let exec ({integer_type_widths} as model_env) ~ret mem = - create_with_length model_env ~ret ~begin_idx - ~end_v:(Sem.eval integer_type_widths end_idx mem) - mem + let begin_itv = Sem.eval integer_type_widths begin_idx mem |> Dom.Val.get_itv in + let end_itv = Sem.eval integer_type_widths end_idx mem |> Dom.Val.get_itv in + let length_itv = Itv.minus end_itv begin_itv in + create_with_length model_env ~ret ~length_itv mem + in + {exec; check= no_check} + + + let create_from_short_arr exp = + let exec ({integer_type_widths} as model_env) ~ret mem = + let mem = create_with_length model_env ~ret ~length_itv:Itv.zero mem in + let deref_of_tgt = + Dom.Mem.find_stack (Loc.of_id (fst ret)) mem + |> Dom.Val.get_pow_loc |> PowLoc.append_field ~fn + in + let src_arr_locs = Dom.Val.get_all_locs (Sem.eval_arr integer_type_widths exp mem) in + Dom.Mem.update_mem deref_of_tgt (Dom.Mem.find_set src_arr_locs mem) mem in {exec; check= no_check} @@ -1439,8 +1452,8 @@ module NSString = struct let create_with_c_string src_exp = let exec model_env ~ret mem = - let v = Sem.eval_string_len src_exp mem in - JavaString.create_with_length model_env ~ret ~begin_idx:Exp.zero ~end_v:v mem + let length_itv = Sem.eval_string_len src_exp mem |> Dom.Val.get_itv in + JavaString.create_with_length model_env ~ret ~length_itv mem in {exec; check= no_check} @@ -1607,7 +1620,9 @@ module Call = struct let open ProcnameDispatcher.Call in let int_typ = Typ.mk (Typ.Tint Typ.IInt) in let char_typ = Typ.mk (Typ.Tint Typ.IChar) in + let short_typ = Typ.mk (Typ.Tint Typ.IUShort) in let char_ptr = Typ.mk (Typ.Tptr (char_typ, Pk_pointer)) in + let short_array = Typ.mk (Typ.Tptr (Typ.mk_array short_typ, Pk_pointer)) in let match_builtin builtin _ s = String.equal s (Procname.get_method builtin) in make_dispatcher [ (* Clang common models *) @@ -1925,6 +1940,8 @@ module Call = struct &:: "" <>$ capt_exp $--> JavaString.empty_constructor ; +PatternMatch.Java.implements_lang "String" &:: "concat" <>$ capt_exp $+ capt_exp $+...$--> JavaString.concat + ; +PatternMatch.Java.implements_lang "String" + &:: "valueOf" <>$ capt_exp_of_prim_typ short_array $--> JavaString.create_from_short_arr ; +PatternMatch.Java.implements_lang "String" &:: "indexOf" <>$ capt_exp $+ any_arg $+...$--> JavaString.indexOf ; +PatternMatch.Java.implements_lang "String" diff --git a/infer/tests/codetoanalyze/java/performance/StringTest.java b/infer/tests/codetoanalyze/java/performance/StringTest.java index ed10e5e13..ae13b02f9 100644 --- a/infer/tests/codetoanalyze/java/performance/StringTest.java +++ b/infer/tests/codetoanalyze/java/performance/StringTest.java @@ -112,4 +112,15 @@ class StringTest { void class_get_canonical_name_constant(Integer a) { for (int i = 0; i < a.getClass().getCanonicalName().length(); i++) {} } + + void string_valueOf_linear(char[] input) { + String s = String.valueOf(input); + for (int i = 0; i < s.length(); i++) {} + } + + void string_valueOf_constant() { + char[] input = {'a', 'b', 'c', 'd', 'e', 'f', 'g'}; + String s = String.valueOf(input); + for (int i = 0; i < s.length(); i++) {} + } } diff --git a/infer/tests/codetoanalyze/java/performance/cost-issues.exp b/infer/tests/codetoanalyze/java/performance/cost-issues.exp index 935ea7d27..24504b18c 100644 --- a/infer/tests/codetoanalyze/java/performance/cost-issues.exp +++ b/infer/tests/codetoanalyze/java/performance/cost-issues.exp @@ -343,6 +343,8 @@ codetoanalyze/java/performance/StringTest.java, StringTest.split_with_limit_line codetoanalyze/java/performance/StringTest.java, StringTest.startsWith_constant():java.lang.String, 18, OnUIThread:false, [] codetoanalyze/java/performance/StringTest.java, StringTest.string_constructor_constant():void, 45, OnUIThread:false, [] codetoanalyze/java/performance/StringTest.java, StringTest.string_constructor_linear(java.lang.String):void, 9 + 5 ⋅ s.length + 3 ⋅ (s.length + 1), OnUIThread:false, [{s.length + 1},Loop,{s.length},Loop] +codetoanalyze/java/performance/StringTest.java, StringTest.string_valueOf_constant():void, 85, OnUIThread:false, [] +codetoanalyze/java/performance/StringTest.java, StringTest.string_valueOf_linear(char[]):void, 8 + 5 ⋅ input.length + 3 ⋅ (input.length + 1), OnUIThread:false, [{input.length + 1},Loop,{input.length},Loop] codetoanalyze/java/performance/StringTest.java, StringTest.substring_linear(java.lang.String,int,int):void, 13 + 8 ⋅ (-x + y), OnUIThread:false, [{-x + y},Loop] codetoanalyze/java/performance/StringTest.java, StringTest.substring_no_end_linear(java.lang.String,int):void, 12 + 8 ⋅ (-x + s.length), OnUIThread:false, [{-x + s.length},Loop] codetoanalyze/java/performance/Switch.java, codetoanalyze.java.performance.Switch.(), 3, OnUIThread:false, []