Merge pull request #1634 from bjorng/bjorn/get_stacktrace-syntax/OTP-14692

Add syntax in try/catch to retrieve the stacktrace directly

14 files changed, 189 insertions, 29 deletions

diff --git a/lib/compiler/src/beam_disasm.erl b/lib/compiler/src/beam_disasm.erl
index 8fd0b36d05..5858b14409 100644
--- a/lib/compiler/src/beam_disasm.erl
+++ b/lib/compiler/src/beam_disasm.erl
@@ -1165,6 +1165,13 @@ resolve_inst({get_map_elements,Args0},_,_,_) ->
     {get_map_elements,FLbl,Src,{list,List}};
 
 %%
+%% OTP 21.
+%%
+
+resolve_inst({build_stacktrace,[]},_,_,_) ->
+    build_stacktrace;
+
+%%
 %% Catches instructions that are not yet handled.
 %%
 resolve_inst(X,_,_,_) -> ?exit({resolve_inst,X}).
diff --git a/lib/compiler/src/beam_disasm.hrl b/lib/compiler/src/beam_disasm.hrl
index d968cd9587..8cc0bcf99b 100644
--- a/lib/compiler/src/beam_disasm.hrl
+++ b/lib/compiler/src/beam_disasm.hrl
@@ -26,7 +26,8 @@
 %%      IT SHOULD BE MOVED TO A FILE THAT DEFINES (AND EXPORTS)
 %%      PROPER TYPES FOR THE SET OF BEAM INSTRUCTIONS.
 %%
--type beam_instr() :: 'bs_init_writable' | 'fclearerror' | 'if_end'
+-type beam_instr() :: 'bs_init_writable' | 'build_stacktrace'
+                    | 'fclearerror' | 'if_end'
                     | 'remove_message' | 'return' | 'send' | 'timeout'
                     | tuple().  %% XXX: Very underspecified - FIX THIS
 
diff --git a/lib/compiler/src/beam_utils.erl b/lib/compiler/src/beam_utils.erl
index dd7ec4da96..1b2a2827cb 100644
--- a/lib/compiler/src/beam_utils.erl
+++ b/lib/compiler/src/beam_utils.erl
@@ -781,6 +781,8 @@ live_opt([{block,Bl0}|Is], Regs0, D, Acc) ->
     {Bl,Regs} = live_opt_block(reverse(Bl0), Regs0, D, [Live0]),
     Live = {'%live',live_regs(Regs),Regs},
     live_opt(Is, Regs, D, [{block,[Live|Bl]}|Acc]);
+live_opt([build_stacktrace=I|Is], _, D, Acc) ->
+    live_opt(Is, live_call(1), D, [I|Acc]);
 live_opt([{label,L}=I|Is], Regs, D0, Acc) ->
     D = gb_trees:insert(L, Regs, D0),
     live_opt(Is, Regs, D, [I|Acc]);
diff --git a/lib/compiler/src/beam_validator.erl b/lib/compiler/src/beam_validator.erl
index be8908dd6b..77f9fcebad 100644
--- a/lib/compiler/src/beam_validator.erl
+++ b/lib/compiler/src/beam_validator.erl
@@ -294,6 +294,8 @@ valfun_1({bs_context_to_binary,Ctx}, #vst{current=#st{x=Xs}}=Vst) ->
     end;
 valfun_1(bs_init_writable=I, Vst) ->
     call(I, 1, Vst);
+valfun_1(build_stacktrace=I, Vst) ->
+    call(I, 1, Vst);
 valfun_1({move,{y,_}=Src,{y,_}=Dst}, Vst) ->
     %% The stack trimming optimization may generate a move from an initialized
     %% but unassigned Y register to another Y register.
diff --git a/lib/compiler/src/genop.tab b/lib/compiler/src/genop.tab
index b5688de339..397e478e1e 100755
--- a/lib/compiler/src/genop.tab
+++ b/lib/compiler/src/genop.tab
@@ -545,3 +545,12 @@ BEAM_FORMAT_NUMBER=0
 ##      Test the arity of Reg and jumps to Lbl if it is not N.
 ##      Test the first element of the tuple and jumps to Lbl if it is not Atom.
 159: is_tagged_tuple/4
+
+# OTP 21
+
+## @spec build_stacktrace
+## @doc  Given the raw stacktrace in x(0), build a cooked stacktrace suitable
+##       for human consumption. Store it in x(0). Destroys all other registers.
+##       Do a garbage collection if necessary to allocate space on the heap
+##       for the result.
+160: build_stacktrace/0
diff --git a/lib/compiler/src/sys_core_fold.erl b/lib/compiler/src/sys_core_fold.erl
index 15ced196a7..f8a467d6a9 100644
--- a/lib/compiler/src/sys_core_fold.erl
+++ b/lib/compiler/src/sys_core_fold.erl
@@ -415,6 +415,8 @@ expr(#c_call{module=M0,name=N0}=Call0, Ctxt, Sub) ->
 	no -> call(Call, M1, N1, Sub);
 	{yes,Seq} -> expr(Seq, Ctxt, Sub)
     end;
+expr(#c_primop{name=#c_literal{val=build_stacktrace}}, effect, _Sub) ->
+    void();
 expr(#c_primop{args=As0}=Prim, _, Sub) ->
     As1 = expr_list(As0, value, Sub),
     Prim#c_primop{args=As1};
diff --git a/lib/compiler/src/v3_codegen.erl b/lib/compiler/src/v3_codegen.erl
index 6a825adbff..74d64e1456 100644
--- a/lib/compiler/src/v3_codegen.erl
+++ b/lib/compiler/src/v3_codegen.erl
@@ -1786,6 +1786,11 @@ internal_cg(bs_init_writable=I, As, Rs, Le, Vdb, Bef, St) ->
     {Sis,Int} = cg_setup_call(As, Bef, Le#l.i, Vdb),
     Reg = load_vars(Rs, clear_regs(Int#sr.reg)),
     {Sis++[I],clear_dead(Int#sr{reg=Reg}, Le#l.i, Vdb),St};
+internal_cg(build_stacktrace=I, As, Rs, Le, Vdb, Bef, St) ->
+    %% This behaves like a function call.
+    {Sis,Int} = cg_setup_call(As, Bef, Le#l.i, Vdb),
+    Reg = load_vars(Rs, clear_regs(Int#sr.reg)),
+    {Sis++[I],clear_dead(Int#sr{reg=Reg}, Le#l.i, Vdb),St};
 internal_cg(raise, As, Rs, Le, Vdb, Bef, St) ->
     %% raise can be treated like a guard BIF.
     bif_cg(raise, As, Rs, Le, Vdb, Bef, St).
diff --git a/lib/compiler/src/v3_core.erl b/lib/compiler/src/v3_core.erl
index 66ddf6fcb9..6029b91cdc 100644
--- a/lib/compiler/src/v3_core.erl
+++ b/lib/compiler/src/v3_core.erl
@@ -920,8 +920,9 @@ try_exception(Ecs0, St0) ->
     %% Note that Tag is not needed for rethrow - it is already in Info.
     {Evs,St1} = new_vars(3, St0), % Tag, Value, Info
     {Ecs1,Ceps,St2} = clauses(Ecs0, St1),
+    Ecs2 = try_build_stacktrace(Ecs1, hd(Evs)),
     [_,Value,Info] = Evs,
-    LA = case Ecs1 of
+    LA = case Ecs2 of
 	     [] -> [];
 	     [C|_] -> get_lineno_anno(C)
 	 end,
@@ -930,7 +931,7 @@ try_exception(Ecs0, St0) ->
 		  body=[#iprimop{anno=#a{},       %Must have an #a{}
 				 name=#c_literal{val=raise},
 				 args=[Info,Value]}]},
-    Hs = [#icase{anno=#a{anno=LA},args=[c_tuple(Evs)],clauses=Ecs1,fc=Ec}],
+    Hs = [#icase{anno=#a{anno=LA},args=[c_tuple(Evs)],clauses=Ecs2,fc=Ec}],
     {Evs,Ceps++Hs,St2}.
 
 try_after(As, St0) ->
@@ -946,6 +947,25 @@ try_after(As, St0) ->
     Hs = [#icase{anno=#a{},args=[c_tuple(Evs)],clauses=[],fc=Ec}],
     {Evs,Hs,St1}.
 
+try_build_stacktrace([#iclause{pats=Ps0,body=B0}=C0|Cs], RawStk) ->
+    [#c_tuple{es=[Class,Exc,Stk]}=Tup] = Ps0,
+    case Stk of
+        #c_var{name='_'} ->
+            %% Stacktrace variable is not used. Nothing to do.
+            [C0|try_build_stacktrace(Cs, RawStk)];
+        _ ->
+            %% Add code to build the stacktrace.
+            Ps = [Tup#c_tuple{es=[Class,Exc,RawStk]}],
+            Call = #iprimop{anno=#a{},
+                            name=#c_literal{val=build_stacktrace},
+                            args=[RawStk]},
+            Iset = #iset{var=Stk,arg=Call},
+            B = [Iset|B0],
+            C = C0#iclause{pats=Ps,body=B},
+            [C|try_build_stacktrace(Cs, RawStk)]
+    end;
+try_build_stacktrace([], _) -> [].
+
 %% expr_bin([ArgExpr], St) -> {[Arg],[PreExpr],St}.
 %%  Flatten the arguments of a bin. Do this straight left to right!
 %%  Note that ibinary needs to have its annotation wrapped in a #a{}
diff --git a/lib/compiler/test/beam_validator_SUITE.erl b/lib/compiler/test/beam_validator_SUITE.erl
index c23514b36b..685eb2a72e 100644
--- a/lib/compiler/test/beam_validator_SUITE.erl
+++ b/lib/compiler/test/beam_validator_SUITE.erl
@@ -421,9 +421,9 @@ try_bin_opt(Mod) ->
     try
 	do_bin_opt(Mod)
     catch
-	Class:Error ->
+	Class:Error:Stk ->
 	    io:format("~p: ~p ~p\n~p\n",
-		      [Mod,Class,Error,erlang:get_stacktrace()]),
+		      [Mod,Class,Error,Stk]),
 	    error
     end.
 
diff --git a/lib/compiler/test/compile_SUITE.erl b/lib/compiler/test/compile_SUITE.erl
index daebbe9d9d..35c11d894d 100644
--- a/lib/compiler/test/compile_SUITE.erl
+++ b/lib/compiler/test/compile_SUITE.erl
@@ -500,9 +500,8 @@ do_kernel_listing({M,A}) ->
 	    io:format("*** compilation failure '~p' for module ~s\n",
 		      [Error,M]),
 	    error;
-	Class:Error ->
-	    io:format("~p: ~p ~p\n~p\n",
-		      [M,Class,Error,erlang:get_stacktrace()]),
+	Class:Error:Stk ->
+	    io:format("~p: ~p ~p\n~p\n", [M,Class,Error,Stk]),
 	    error
     end.
 
@@ -902,9 +901,8 @@ do_core_pp({M,A}, Outdir) ->
 	    io:format("*** compilation failure '~p' for module ~s\n",
 		      [Error,M]),
 	    error;
-	Class:Error ->
-	    io:format("~p: ~p ~p\n~p\n",
-		      [M,Class,Error,erlang:get_stacktrace()]),
+	Class:Error:Stk ->
+	    io:format("~p: ~p ~p\n~p\n", [M,Class,Error,Stk]),
 	    error
     end.
 
@@ -961,9 +959,8 @@ do_core_roundtrip(Beam, Outdir) ->
 	    io:format("*** compilation failure '~p' for file ~s\n",
 		      [Error,Beam]),
 	    error;
-	Class:Error ->
-	    io:format("~p: ~p ~p\n~p\n",
-		      [Beam,Class,Error,erlang:get_stacktrace()]),
+	Class:Error:Stk ->
+	    io:format("~p: ~p ~p\n~p\n", [Beam,Class,Error,Stk]),
 	    error
     end.
 
@@ -1148,9 +1145,8 @@ do_asm(Beam, Outdir) ->
 			  [Other,AsmFile]),
 		error
 	end
-    catch Class:Error ->
-	    io:format("~p: ~p ~p\n~p\n",
-		      [M,Class,Error,erlang:get_stacktrace()]),
+    catch Class:Error:Stk ->
+	    io:format("~p: ~p ~p\n~p\n", [M,Class,Error,Stk]),
 	    error
     end.
 
@@ -1167,9 +1163,8 @@ do_opt_guards(Beam) ->
     try
 	{ok,M,Asm} = compile:forms(A, ['S']),
 	do_opt_guards_mod(Asm)
-    catch Class:Error ->
-	    io:format("~p: ~p ~p\n~p\n",
-		      [M,Class,Error,erlang:get_stacktrace()]),
+    catch Class:Error:Stk ->
+	    io:format("~p: ~p ~p\n~p\n", [M,Class,Error,Stk]),
 	    error
     end.
 
diff --git a/lib/compiler/test/misc_SUITE.erl b/lib/compiler/test/misc_SUITE.erl
index b12bcbeeab..d93c5dda1e 100644
--- a/lib/compiler/test/misc_SUITE.erl
+++ b/lib/compiler/test/misc_SUITE.erl
@@ -318,8 +318,7 @@ expect_error(Fun) ->
 	    io:format("~p", [Any]),
 	    ct:fail(call_was_supposed_to_fail)
     catch
-	Class:Reason ->
-	    Stk = erlang:get_stacktrace(),
+	Class:Reason:Stk ->
 	    io:format("~p:~p\n~p\n", [Class,Reason,Stk]),
 	    case {Class,Reason} of
 		{error,undef} ->
diff --git a/lib/compiler/test/receive_SUITE.erl b/lib/compiler/test/receive_SUITE.erl
index 3001bb421b..5e386790c0 100644
--- a/lib/compiler/test/receive_SUITE.erl
+++ b/lib/compiler/test/receive_SUITE.erl
@@ -222,9 +222,8 @@ do_ref_opt(Source, PrivDir) ->
 		    collect_recv_opt_instrs(Code)
 	end,
 	ok
-    catch Class:Error ->
-	    io:format("~s: ~p ~p\n~p\n",
-		      [Source,Class,Error,erlang:get_stacktrace()]),
+    catch Class:Error:Stk ->
+	    io:format("~s: ~p ~p\n~p\n", [Source,Class,Error,Stk]),
 	    error
     end.
 
diff --git a/lib/compiler/test/trycatch_SUITE.erl b/lib/compiler/test/trycatch_SUITE.erl
index 42dbf7d5f0..8cf7928cc4 100644
--- a/lib/compiler/test/trycatch_SUITE.erl
+++ b/lib/compiler/test/trycatch_SUITE.erl
@@ -26,7 +26,8 @@
 	 nested_of/1,nested_catch/1,nested_after/1,
 	 nested_horrid/1,last_call_optimization/1,bool/1,
 	 plain_catch_coverage/1,andalso_orelse/1,get_in_try/1,
-	 hockey/1,handle_info/1,catch_in_catch/1,grab_bag/1]).
+	 hockey/1,handle_info/1,catch_in_catch/1,grab_bag/1,
+         stacktrace/1,nested_stacktrace/1]).
 
 -include_lib("common_test/include/ct.hrl").
 
@@ -42,7 +43,8 @@ groups() ->
        after_oops,eclectic,rethrow,nested_of,nested_catch,
        nested_after,nested_horrid,last_call_optimization,
        bool,plain_catch_coverage,andalso_orelse,get_in_try,
-       hockey,handle_info,catch_in_catch,grab_bag]}].
+       hockey,handle_info,catch_in_catch,grab_bag,
+       stacktrace,nested_stacktrace]}].
 
 
 init_per_suite(Config) ->
@@ -1039,5 +1041,123 @@ grab_bag(_Config) ->
 
     ok.
 
+stacktrace(_Config) ->
+    V = [make_ref()|self()],
+    case ?MODULE:module_info(native) of
+        false ->
+            {value2,{caught1,badarg,[{erlang,abs,[V],_}|_]}} =
+                stacktrace_1({'abs',V}, error, {value,V}),
+            {caught2,{error,badarith},[{erlang,'+',[0,a],_},
+                                       {?MODULE,my_add,2,_}|_]} =
+                stacktrace_1({'div',{1,0}}, error, {'add',{0,a}});
+        true ->
+            {value2,{caught1,badarg,[{?MODULE,my_abs,1,_}|_]}} =
+                stacktrace_1({'abs',V}, error, {value,V}),
+            {caught2,{error,badarith},[{?MODULE,my_add,2,_}|_]} =
+                stacktrace_1({'div',{1,0}}, error, {'add',{0,a}})
+    end,
+    {caught2,{error,{try_clause,V}},[{?MODULE,stacktrace_1,3,_}|_]} =
+        stacktrace_1({value,V}, error, {value,V}),
+    {caught2,{throw,V},[{?MODULE,foo,1,_}|_]} =
+        stacktrace_1({value,V}, error, {throw,V}),
+
+    try
+        stacktrace_2()
+    catch
+        error:{badmatch,_}:Stk2 ->
+            [{?MODULE,stacktrace_2,0,_},
+             {?MODULE,stacktrace,1,_}|_] = Stk2,
+            Stk2 = erlang:get_stacktrace(),
+            ok
+    end,
+
+    try
+        stacktrace_3(a, b)
+    catch
+        error:function_clause:Stk3 ->
+            Stk3 = erlang:get_stacktrace(),
+            case lists:module_info(native) of
+                false ->
+                    [{lists,prefix,[a,b],_}|_] = Stk3;
+                true ->
+                    [{lists,prefix,2,_}|_] = Stk3
+            end
+    end,
+
+    try
+        throw(x)
+    catch
+        throw:x:IntentionallyUnused ->
+            ok
+    end.
+
+stacktrace_1(X, C1, Y) ->
+    try try foo(X) of
+            C1 -> value1
+        catch
+            C1:D1:Stk1 ->
+                Stk1 = erlang:get_stacktrace(),
+                {caught1,D1,Stk1}
+        after
+            foo(Y)
+        end of
+        V2 -> {value2,V2}
+    catch
+        C2:D2:Stk2 -> {caught2,{C2,D2},Stk2=erlang:get_stacktrace()}
+    end.
+
+stacktrace_2() ->
+    ok = erlang:process_info(self(), current_function),
+    ok.
+
+stacktrace_3(A, B) ->
+    {ok,lists:prefix(A, B)}.
+
+nested_stacktrace(_Config) ->
+    V = [{make_ref()}|[self()]],
+    value1 = nested_stacktrace_1({{value,{V,x1}},void,{V,x1}},
+                                 {void,void,void}),
+    case ?MODULE:module_info(native) of
+        false ->
+            {caught1,
+             [{erlang,'+',[V,x1],_},{?MODULE,my_add,2,_}|_],
+             value2} =
+                nested_stacktrace_1({{'add',{V,x1}},error,badarith},
+                                    {{value,{V,x2}},void,{V,x2}}),
+            {caught1,
+             [{erlang,'+',[V,x1],_},{?MODULE,my_add,2,_}|_],
+             {caught2,[{erlang,abs,[V],_}|_]}} =
+                nested_stacktrace_1({{'add',{V,x1}},error,badarith},
+                                    {{'abs',V},error,badarg});
+        true ->
+            {caught1,
+             [{?MODULE,my_add,2,_}|_],
+             value2} =
+                nested_stacktrace_1({{'add',{V,x1}},error,badarith},
+                                    {{value,{V,x2}},void,{V,x2}}),
+            {caught1,
+             [{?MODULE,my_add,2,_}|_],
+             {caught2,[{?MODULE,my_abs,1,_}|_]}} =
+                nested_stacktrace_1({{'add',{V,x1}},error,badarith},
+                                    {{'abs',V},error,badarg})
+    end,
+    ok.
+
+nested_stacktrace_1({X1,C1,V1}, {X2,C2,V2}) ->
+    try foo(X1) of
+        V1 -> value1
+    catch
+        C1:V1:S1 ->
+            S1 = erlang:get_stacktrace(),
+            T2 = try foo(X2) of
+                     V2 -> value2
+                 catch
+                     C2:V2:S2 ->
+                         S2 = erlang:get_stacktrace(),
+                         {caught2,S2}
+                 end,
+            {caught1,S1,T2}
+    end.
+
 
 id(I) -> I.
diff --git a/lib/compiler/test/z_SUITE.erl b/lib/compiler/test/z_SUITE.erl
index d864184f4c..cd95d0e733 100644
--- a/lib/compiler/test/z_SUITE.erl
+++ b/lib/compiler/test/z_SUITE.erl
@@ -54,8 +54,7 @@ do_loaded([{M,_}|Ms], E0) ->
 	    _ = M:module_info(functions),
 	    E0
 	catch
-	    C:Error ->
-		Stk = erlang:get_stacktrace(),
+	    C:Error:Stk ->
 		io:format("~p:~p\n~p\n", [C,Error,Stk]),
 		E0 + 1
 	end,