aboutsummaryrefslogtreecommitdiffstats
path: root/lib/debugger/src/dbg_istk.erl
blob: a0d3069d50d6fec380c7c36aa420ecdd6809611e (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2011. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved online at http://www.erlang.org/.
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%%
%% %CopyrightEnd%
%%
-module(dbg_istk).
-export([init/0,delayed_to_external/0,from_external/1,
	 push/2,pop/0,pop/1,stack_level/0,
	 delayed_stacktrace/0,delayed_stacktrace/2,
	 bindings/1,stack_frame/2,backtrace/2,
	 in_use_p/2]).

-include("dbg_ieval.hrl").

-define(STACK, ?MODULE).

-record(e,
	{level,					%Level
	 mfa,					%{Mod,Func,Args|Arity}|{Fun,Args}
	 line,					%Line called from
	 bindings
	 }).

init() ->
    init([]).

delayed_to_external() ->
    Stack = get(?STACK),
    fun() -> {stack,term_to_binary(Stack)} end.

from_external({stack,Stk}) ->
    put(?STACK, binary_to_term(Stk)).

init(Stack) ->
    put(?STACK, Stack).

%% We keep track of a call stack that is used for
%%  1) saving stack frames that can be inspected from an Attached
%%     Process GUI (using dbg_icmd:get(Meta, stack_frame, {Dir, SP})
%%  2) generate an approximation of regular stacktrace -- sent to
%%     Debugged when it should raise an exception or evaluate a
%%     function (since it might possible raise an exception)
%%
%% How to push depends on the "Stack Trace" option (value saved in
%% process dictionary item 'trace_stack').
%%   all - everything is pushed
%%   no_tail - tail recursive push
%%   false - nothing is pushed
%% Whenever a function returns, the corresponding call frame is popped.

push(Bs, #ieval{level=Le,module=Mod,function=Name,arguments=As,
		line=Li,top=Lc}=Ieval) ->
    Entry = #e{level=Le,mfa={Mod,Name,As},line=Li,bindings=Bs},
    case get(trace_stack) of
	false ->
	    Ieval#ieval{level=Le+1};
	no_tail when Lc ->
	    Ieval;
	_ -> % all | no_tail when Lc =:= false
	    put(?STACK, [Entry|get(?STACK)]),
	    Ieval#ieval{level=Le+1}
    end.

pop() ->
    case get(trace_stack) of
	false -> ignore;
	_ -> % all ¦ no_tail
	    case get(?STACK) of
		[_Entry|Entries] ->
		    put(?STACK, Entries);
		[] ->
		    ignore
	    end
    end.

pop(Le) ->
    case get(trace_stack) of
	false -> ignore;
	_ -> % all | no_tail
	    put(?STACK, pop(Le, get(?STACK)))
    end.

pop(Level, [#e{level=Le}|Stack]) when Level =< Le ->
    pop(Level, Stack);
pop(_Level, Stack) ->
    Stack.

%% stack_level() -> Le
%% stack_level(Stack) -> Le
%% Top call level
stack_level() ->
    stack_level(get(?STACK)).

stack_level([]) -> 1;
stack_level([#e{level=Le}|_]) -> Le.

%% delayed_stacktrace() -> CreateStacktraceFun
%% delayed_stacktrace(ArgFlag, #ieval{}) -> CreateStacktraceFun
%%   ArgFlag = no_args | include_args
%%   CreateStacktraceFun = fun(NumberOfEntries)
%%
%% Return a fun that can convert the internal stack format to
%% an imitation of the regular stacktrace.

delayed_stacktrace() ->
    Stack0 = get(?STACK),
    fun(NumEntries) ->
	    Stack = stacktrace(NumEntries, Stack0, []),
	    [ArityOnly || {ArityOnly,_} <- Stack]
    end.

delayed_stacktrace(include_args, Ieval) ->
    #ieval{module=Mod,function=Name,arguments=As} = Ieval,
    Stack0 = [#e{mfa={Mod,Name,As}}|get(?STACK)],
    fun(NumEntries) ->
	    case stacktrace(NumEntries, Stack0, []) of
		[] ->
		    [];
		[{_,WithArgs}|Stack] ->
		    [WithArgs | [ArityOnly || {ArityOnly,_} <- Stack]]
	    end
    end;
delayed_stacktrace(no_args, Ieval) ->
    #ieval{module=Mod,function=Name,arguments=As} = Ieval,
    Stack0 = [#e{mfa={Mod,Name,As}}|get(?STACK)],
    fun(NumEntries) ->
	    Stack = stacktrace(NumEntries, Stack0, []),
	    [ArityOnly || {ArityOnly,_} <- Stack]
    end.

stacktrace(N, [E|T], []) ->
    stacktrace(N-1, T, [normalize(E)]);
stacktrace(N, [E|T], [{P,_}|_]=Acc) when N > 0 ->
    case normalize(E) of
	{P,_} ->
	    stacktrace(N, T, Acc);
	New ->
	    stacktrace(N-1, T, [New|Acc])
    end;
stacktrace(_, _, Acc) ->
    lists:reverse(Acc).

normalize(#e{mfa={_,Fun,As}}) when is_function(Fun) ->
    {{Fun,length(As)},{Fun,As}};
normalize(#e{mfa={M,F,As}}) ->
    {{M,F,length(As)},{M,F,As}}.

%% bindings(SP) -> Bs
%%   SP = Le  % stack pointer
%% Return the bindings for the specified call level
bindings(SP) ->
    bindings(SP, get(?STACK)).

bindings(SP, [#e{level=SP,bindings=Bs}|_]) ->
    Bs;
bindings(SP, [_Entry|Entries]) ->
    bindings(SP, Entries);
bindings(_SP, []) ->
    erl_eval:new_bindings().

%% stack_frame(Dir, SP) -> {Le, Where, Bs} | top | bottom
%%   Dir = up | down
%%   Where = {Cm, Li}
%%     Cm = Module | undefined  % module
%%     Li = int()  | -1         % line number
%%     Bs = bindings()
%% Return stack frame info one step up/down from given stack pointer
%%  up = to lower call levels
%%  down = to higher call levels
stack_frame(up, SP) ->
    stack_frame(SP, up, get(?STACK));
stack_frame(down, SP) ->
    stack_frame(SP, down, lists:reverse(get(?STACK))).

stack_frame(SP, up, [#e{level=Le,mfa={Cm,_,_},line=Li,bindings=Bs}|_])
  when Le < SP ->
    {Le,{Cm,Li},Bs};
stack_frame(SP, down, [#e{level=Le,mfa={Cm,_,_},line=Li,bindings=Bs}|_])
  when Le > SP ->
    {Le,{Cm,Li},Bs};
stack_frame(SP, Dir, [#e{level=SP}|Stack]) ->
    case Stack of
	[#e{level=Le,mfa={Cm,_,_},line=Li,bindings=Bs}|_] ->
	    {Le,{Cm,Li},Bs};
	[] when Dir =:= up ->
	    top;
	[] when Dir =:= down ->
	    bottom
    end;
stack_frame(SP, Dir, [_Entry|Stack]) ->
    stack_frame(SP, Dir, Stack).

%% backtrace(HowMany) -> Backtrace
%%   HowMany = all | int()
%%   Backtrace = {Le, MFA}
%% Return all/the last N called functions, in reversed call order
backtrace(HowMany, Ieval) ->
    #ieval{level=Level,module=Mod,function=Name,arguments=As} = Ieval,
    Stack0 = [#e{level=Level,mfa={Mod,Name,As}}|get(?STACK)],
    Stack = case HowMany of
		all -> Stack0;
		N -> lists:sublist(Stack0, N)
	    end,
    [{Le,MFA} || #e{level=Le,mfa=MFA} <- Stack].

%%--------------------------------------------------------------------
%% in_use_p(Mod, Cm) -> boolean()
%%   Mod = Cm = atom()
%% Returns true if Mod is found on the stack, otherwise false.
%%--------------------------------------------------------------------
in_use_p(Mod, Mod) -> true;
in_use_p(Mod, _Cm) ->
    case get(trace_stack) of
	false -> true;
	_ -> %  all | no_tail
	    lists:any(fun(#e{mfa={M,_,_}}) when M =:= Mod -> true;
			 (_) -> false
		      end, get(?STACK))
    end.