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authorLukas Larsson <[email protected]>2017-10-06 18:09:22 +0200
committerLukas Larsson <[email protected]>2017-10-09 11:51:28 +0200
commit01ee7763bcaf9192bedba2833f8b0717df1c4b23 (patch)
treeaa144d5030d8be5c3850db1cc9ff964aac465a16
parentb4b81a3342af35308e87e34380d870c2464be697 (diff)
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erts: Fix caller trace for apply bifs
Bifs that are called through the export entry using i_call_last could have their cp set to return_trace, just like any other call. So we have to unwind the trace stack to get the correct cp. Not doing this creates a lot of issues for fprof.
-rw-r--r--erts/emulator/beam/beam_bp.c85
-rw-r--r--erts/emulator/test/match_spec_SUITE.erl48
2 files changed, 97 insertions, 36 deletions
diff --git a/erts/emulator/beam/beam_bp.c b/erts/emulator/beam/beam_bp.c
index 950639f7ae..069e7391fd 100644
--- a/erts/emulator/beam/beam_bp.c
+++ b/erts/emulator/beam/beam_bp.c
@@ -642,6 +642,49 @@ erts_clear_export_break(Module* modp, ErtsCodeInfo *ci)
ASSERT(ci->u.gen_bp == NULL);
}
+/*
+ * If c_p->cp is a trace return instruction, we set cp
+ * to be the place where we again start to execute code.
+ *
+ * cp is used by match spec {caller} to get the calling
+ * function, and if we don't do this fixup it will be
+ * 'undefined'. This has the odd side effect of {caller}
+ * not really being which function is the caller, but
+ * rather which function we are about to return to.
+ */
+static void fixup_cp_before_trace(Process *c_p, int *return_to_trace)
+{
+ Eterm *cpp, *E = c_p->stop;
+ BeamInstr w = *c_p->cp;
+ if (w == (BeamInstr) BeamOp(op_return_trace)) {
+ cpp = &E[2];
+ } else if (w == (BeamInstr) BeamOp(op_i_return_to_trace)) {
+ *return_to_trace = 1;
+ cpp = &E[0];
+ } else if (w == (BeamInstr) BeamOp(op_i_return_time_trace)) {
+ cpp = &E[0];
+ } else {
+ cpp = NULL;
+ }
+ if (cpp) {
+ for (;;) {
+ BeamInstr w = *cp_val(*cpp);
+ if (w == (BeamInstr) BeamOp(op_return_trace)) {
+ cpp += 3;
+ } else if (w == (BeamInstr) BeamOp(op_i_return_to_trace)) {
+ *return_to_trace = 1;
+ cpp += 1;
+ } else if (w == (BeamInstr) BeamOp(op_i_return_time_trace)) {
+ cpp += 2;
+ } else {
+ break;
+ }
+ }
+ c_p->cp = (BeamInstr *) cp_val(*cpp);
+ ASSERT(is_CP(*cpp));
+ }
+}
+
BeamInstr
erts_generic_breakpoint(Process* c_p, ErtsCodeInfo *info, Eterm* reg)
{
@@ -752,6 +795,7 @@ erts_bif_trace(int bif_index, Process* p, Eterm* args, BeamInstr* I)
GenericBp* g;
GenericBpData* bp = NULL;
Uint bp_flags = 0;
+ int return_to_trace = 0;
ERTS_SMP_CHK_HAVE_ONLY_MAIN_PROC_LOCK(p);
@@ -767,6 +811,8 @@ erts_bif_trace(int bif_index, Process* p, Eterm* args, BeamInstr* I)
*/
if (!applying) {
p->cp = I;
+ } else {
+ fixup_cp_before_trace(p, &return_to_trace);
}
if (bp_flags & (ERTS_BPF_LOCAL_TRACE|ERTS_BPF_GLOBAL_TRACE) &&
IS_TRACED_FL(p, F_TRACE_CALLS)) {
@@ -945,49 +991,20 @@ static ErtsTracer
do_call_trace(Process* c_p, ErtsCodeInfo* info, Eterm* reg,
int local, Binary* ms, ErtsTracer tracer)
{
- Eterm* cpp;
int return_to_trace = 0;
- BeamInstr w;
BeamInstr *cp_save = c_p->cp;
Uint32 flags;
Uint need = 0;
Eterm* E = c_p->stop;
- w = *c_p->cp;
- if (w == (BeamInstr) BeamOp(op_return_trace)) {
- cpp = &E[2];
- } else if (w == (BeamInstr) BeamOp(op_i_return_to_trace)) {
- return_to_trace = 1;
- cpp = &E[0];
- } else if (w == (BeamInstr) BeamOp(op_i_return_time_trace)) {
- cpp = &E[0];
- } else {
- cpp = NULL;
- }
- if (cpp) {
- for (;;) {
- BeamInstr w = *cp_val(*cpp);
- if (w == (BeamInstr) BeamOp(op_return_trace)) {
- cpp += 3;
- } else if (w == (BeamInstr) BeamOp(op_i_return_to_trace)) {
- return_to_trace = 1;
- cpp += 1;
- } else if (w == (BeamInstr) BeamOp(op_i_return_time_trace)) {
- cpp += 2;
- } else {
- break;
- }
- }
- cp_save = c_p->cp;
- c_p->cp = (BeamInstr *) cp_val(*cpp);
- ASSERT(is_CP(*cpp));
- }
+ fixup_cp_before_trace(c_p, &return_to_trace);
+
ERTS_SMP_UNREQ_PROC_MAIN_LOCK(c_p);
flags = erts_call_trace(c_p, info, ms, reg, local, &tracer);
ERTS_SMP_REQ_PROC_MAIN_LOCK(c_p);
- if (cpp) {
- c_p->cp = cp_save;
- }
+
+ /* restore cp after potential fixup */
+ c_p->cp = cp_save;
ASSERT(!ERTS_PROC_IS_EXITING(c_p));
if ((flags & MATCH_SET_RETURN_TO_TRACE) && !return_to_trace) {
diff --git a/erts/emulator/test/match_spec_SUITE.erl b/erts/emulator/test/match_spec_SUITE.erl
index 92ddc23592..08a7b4560c 100644
--- a/erts/emulator/test/match_spec_SUITE.erl
+++ b/erts/emulator/test/match_spec_SUITE.erl
@@ -21,7 +21,7 @@
-module(match_spec_SUITE).
-export([all/0, suite/0, not_run/1]).
--export([test_1/1, test_2/1, test_3/1, bad_match_spec_bin/1,
+-export([test_1/1, test_2/1, test_3/1, caller_and_return_to/1, bad_match_spec_bin/1,
trace_control_word/1, silent/1, silent_no_ms/1, silent_test/1,
ms_trace2/1, ms_trace3/1, ms_trace_dead/1, boxed_and_small/1,
destructive_in_test_bif/1, guard_exceptions/1,
@@ -47,7 +47,7 @@ suite() ->
all() ->
case test_server:is_native(match_spec_SUITE) of
false ->
- [test_1, test_2, test_3, bad_match_spec_bin,
+ [test_1, test_2, test_3, caller_and_return_to, bad_match_spec_bin,
trace_control_word, silent, silent_no_ms, silent_test, ms_trace2,
ms_trace3, ms_trace_dead, boxed_and_small, destructive_in_test_bif,
guard_exceptions, unary_plus, unary_minus, fpe,
@@ -180,6 +180,50 @@ test_3(Config) when is_list(Config) ->
collect(P1, [{trace, P1, call, {?MODULE, f2, [a, b]}, [true]}]),
ok.
+%% Test that caller and return to work as they should
+%% There was a bug where caller would be undefined when return_to was set
+%% for r the bif erlang:put().
+caller_and_return_to(Config) ->
+ tr(
+ fun do_put_wrapper/0,
+ fun (Tracee) ->
+ MsgCaller = [{'_',[],[{message,{caller}}]}],
+ 1 = erlang:trace(Tracee, true, [call,return_to]),
+ 1 = erlang:trace_pattern( {?MODULE,do_put,1}, MsgCaller, [local]),
+ 1 = erlang:trace_pattern( {?MODULE,do_the_put,1}, MsgCaller, [local]),
+ 1 = erlang:trace_pattern( {erlang,integer_to_list,1}, MsgCaller, [local]),
+ 1 = erlang:trace_pattern( {erlang,put,2}, MsgCaller, [local]),
+
+ [{trace,Tracee,call,{?MODULE,do_put,[test]},{?MODULE,do_put_wrapper,0}},
+ {trace,Tracee,call,{?MODULE,do_the_put,[test]},{?MODULE,do_put,1}},
+ {trace,Tracee,call,{erlang,integer_to_list,[1]},{?MODULE,do_the_put,1}},
+ {trace,Tracee,return_to,{?MODULE,do_the_put,1}},
+ {trace,Tracee,call,{erlang,put,[test,"1"]},{?MODULE,do_put,1}},
+ {trace,Tracee,return_to,{?MODULE,do_put,1}},
+
+ %% These last trace messages are a bit strange...
+ %% if call tracing had been enabled for do_put_wrapper
+ %% then caller and return_to would have been {?MODULE,do_put_wrapper,1}
+ %% but since it is not, they are set to do_put instead, but we still
+ %% get the do_put_wrapper return_to message...
+ {trace,Tracee,call,{erlang,integer_to_list,[2]},{?MODULE,do_put,1}},
+ {trace,Tracee,return_to,{?MODULE,do_put,1}},
+ {trace,Tracee,return_to,{?MODULE,do_put_wrapper,0}}
+ ]
+ end),
+ ok.
+
+do_put_wrapper() ->
+ do_put(test),
+ ok.
+
+do_put(Var) ->
+ do_the_put(Var),
+ erlang:integer_to_list(id(2)).
+do_the_put(Var) ->
+ Lst = erlang:integer_to_list(id(1)),
+ erlang:put(Var, Lst).
+
otp_9422(Config) when is_list(Config) ->
Laps = 10000,
Fun1 = fun() -> otp_9422_tracee() end,