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author | Björn Gustavsson <bjorn@erlang.org> | 2011-03-31 07:31:14 +0200 |
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committer | Björn Gustavsson <bjorn@erlang.org> | 2011-08-16 08:58:47 +0200 |
commit | e0fe23461cc94a80e02a9542ab2182f62badd5de (patch) | |
tree | 2ec0499d0b23c64d88880eb1c8e8c8830dfce8ea /lib/debugger/src/dbg_ieval.erl | |
parent | 3ccc4730e54f0f9e86bf96360b7600ab8c9e1d47 (diff) | |
download | otp-e0fe23461cc94a80e02a9542ab2182f62badd5de.tar.gz otp-e0fe23461cc94a80e02a9542ab2182f62badd5de.tar.bz2 otp-e0fe23461cc94a80e02a9542ab2182f62badd5de.zip |
Don't build stacktrace until erlang:get_stacktrace() is called
Currently, dbg_istk:exception_stacktrace/2 does not do a very good job
imitating BEAM's stacktrace. The reason is that it need to be
relatively fast since a simulated stacktrace is constructed not only
when an exception oocurs, but also before every call to
non-interpreted code.
To prepare for a future more thorough (and slower) stacktrace
construction, refactor the building of the stacktrace so that
it only is done when erlang:get_stacktrace/0 is called.
Diffstat (limited to 'lib/debugger/src/dbg_ieval.erl')
-rw-r--r-- | lib/debugger/src/dbg_ieval.erl | 38 |
1 files changed, 29 insertions, 9 deletions
diff --git a/lib/debugger/src/dbg_ieval.erl b/lib/debugger/src/dbg_ieval.erl index 445eba3346..fe7f9af1a9 100644 --- a/lib/debugger/src/dbg_ieval.erl +++ b/lib/debugger/src/dbg_ieval.erl @@ -168,7 +168,7 @@ check_exit_msg(_Msg, _Bs, _Ieval) -> %% and then raise the exception. %%-------------------------------------------------------------------- exception(Class, Reason, Bs, Ieval) -> - exception(Class, Reason, dbg_istk:exception_stacktrace(complete, Ieval), + exception(Class, Reason, dbg_istk:delayed_stacktrace(Ieval), Bs, Ieval). exception(Class, Reason, Stacktrace, Bs, #ieval{module=M, line=Line}) -> @@ -226,8 +226,7 @@ meta(Int, Debugged, M, F, As) -> debugged_cmd(Cmd, Bs, Ieval) -> Debugged = get(self), - Stacktrace = dbg_istk:exception_stacktrace(no_current, Ieval), - Debugged ! {sys, self(), {command,Cmd,Stacktrace}}, + Debugged ! {sys, self(), {command,Cmd}}, meta_loop(Debugged, Bs, Ieval). meta_loop(Debugged, Bs, #ieval{level=Le} = Ieval) -> @@ -240,12 +239,17 @@ meta_loop(Debugged, Bs, #ieval{level=Le} = Ieval) -> {value, Val, Bs}; {sys, Debugged, {value,Val,Bs2}} -> {value, Val, Bs2}; - {sys, Debugged, {exception,{Class,Reason,Stacktrace}}} -> + {sys, Debugged, {exception,{Class,Reason,Stk}}} -> case get(exit_info) of - %% Error occured outside interpreted code + %% Error occurred outside of interpreted code. undefined -> - exception(Class,Reason,Stacktrace,Bs,Ieval); + MakeStk0 = dbg_istk:delayed_stacktrace(), + MakeStk = fun(Depth0) -> + Depth = max(0, Depth0 - length(Stk)), + Stk ++ MakeStk0(Depth) + end, + exception(Class, Reason, MakeStk, Bs, Ieval); %% Error must have occured within a re-entry to %% interpreted code, simply raise the exception @@ -370,7 +374,7 @@ format_args1([]) -> %% Mimic catch behaviour catch_value(error, Reason) -> - {'EXIT',{Reason,get(stacktrace)}}; + {'EXIT',{Reason,get_stacktrace()}}; catch_value(exit, Reason) -> {'EXIT',Reason}; catch_value(throw, Reason) -> @@ -395,7 +399,7 @@ eval_mfa(Debugged, M, F, As, #ieval{level=Le}=Ieval0) -> exit:{Int, Reason} -> exit(Reason); Class:Reason -> - {exception, {Class, Reason, get(stacktrace)}} + {exception, {Class, Reason, get_stacktrace()}} end. eval_function(Mod, Name, As, Bs, Called, Ieval0) -> @@ -782,7 +786,7 @@ expr({dbg,Line,self,[]}, Bs, #ieval{level=Le}) -> {value,Self,Bs}; expr({dbg,Line,get_stacktrace,[]}, Bs, #ieval{level=Le}) -> trace(bif, {Le,Line,erlang,get_stacktrace,[]}), - Stacktrace = get(stacktrace), + Stacktrace = get_stacktrace(), trace(return, {Le,Stacktrace}), {value,Stacktrace,Bs}; expr({dbg,Line,throw,As0}, Bs0, #ieval{level=Le}=Ieval0) -> @@ -1501,3 +1505,19 @@ add_binding(N,Val,[B1|Bs]) -> [B1|add_binding(N,Val,Bs)]; add_binding(N,Val,[]) -> [{N,Val}]. + +%% get_stacktrace() -> Stacktrace +%% Return the latest stacktrace for the process. +get_stacktrace() -> + case get(stacktrace) of + MakeStk when is_function(MakeStk, 1) -> + %% The stacktrace has not been constructed before. + %% Construct it and remember the result. + Depth = erlang:system_flag(backtrace_depth, 8), + erlang:system_flag(backtrace_depth, Depth), + Stk = MakeStk(Depth), + put(stacktrace, Stk), + Stk; + Stk when is_list(Stk) -> + Stk + end. |