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

Add syntax in try/catch to retrieve the stacktrace directly

15 files changed, 82 insertions, 89 deletions

diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml
index daf3002ec7..d7404fa3ce 100644
--- a/erts/doc/src/erlang.xml
+++ b/erts/doc/src/erlang.xml
@@ -1985,39 +1985,26 @@ true</pre>
       <fsummary>Get the call stack back-trace of the last exception.</fsummary>
       <type name="stack_item"/>
       <desc>
-        <p>Gets the call stack back-trace (<em>stacktrace</em>) for an
-          exception that has just been caught
-	  in the calling process as a list of
-          <c>{<anno>Module</anno>,<anno>Function</anno>,<anno>Arity</anno>,<anno>Location</anno>}</c>
-          tuples. Field <c><anno>Arity</anno></c> in the first tuple can be the
-          argument list of that function call instead of an arity integer,
-          depending on the exception.</p>
-        <p>If there has not been any exceptions in a process, the
-          stacktrace is <c>[]</c>. After a code change for the process,
-          the stacktrace can also be reset to <c>[]</c>.</p>
-	<p><c>erlang:get_stacktrace/0</c> is only guaranteed to return
-	a stacktrace if called (directly or indirectly) from within the
-	scope of a <c>try</c> expression. That is, the following call works:</p>
+	<warning><p><c>erlang:get_stacktrace/0</c> is deprecated and will stop working
+	in a future release.</p></warning>
+      <p>Instead of using <c>erlang:get_stacktrace/0</c> to retrieve
+      the call stack back-trace, use the following syntax:</p>
 <pre>
 try Expr
 catch
-  C:R ->
-   {C,R,erlang:get_stacktrace()}
+  Class:Reason:Stacktrace ->
+   {Class,Reason,Stacktrace}
 end</pre>
-	<p>As does this call:</p>
-<pre>
-try Expr
-catch
-  C:R ->
-   {C,R,helper()}
-end
-
-helper() ->
-  erlang:get_stacktrace().</pre>
-
-        <warning><p>In a future release,
-        <c>erlang:get_stacktrace/0</c> will return <c>[]</c> if called
-        from outside a <c>try</c> expression.</p></warning>
+        <p><c>erlang:get_stacktrace/0</c> retrieves the call stack back-trace
+        (<em>stacktrace</em>) for an exception that has just been
+        caught in the calling process as a list of
+        <c>{<anno>Module</anno>,<anno>Function</anno>,<anno>Arity</anno>,<anno>Location</anno>}</c>
+        tuples. Field <c><anno>Arity</anno></c> in the first tuple can
+        be the argument list of that function call instead of an arity
+        integer, depending on the exception.</p>
+        <p>If there has not been any exceptions in a process, the
+          stacktrace is <c>[]</c>. After a code change for the process,
+          the stacktrace can also be reset to <c>[]</c>.</p>
         <p>The stacktrace is the same data as operator <c>catch</c>
           returns, for example:</p>
         <pre>
diff --git a/erts/emulator/beam/instrs.tab b/erts/emulator/beam/instrs.tab
index d934abb217..b92152238e 100644
--- a/erts/emulator/beam/instrs.tab
+++ b/erts/emulator/beam/instrs.tab
@@ -931,3 +931,8 @@ i_raise() {
     //| -no_next
 }
 
+build_stacktrace() {
+    SWAPOUT;
+    x(0) = build_stacktrace(c_p, x(0));
+    SWAPIN;
+}
diff --git a/erts/emulator/beam/ops.tab b/erts/emulator/beam/ops.tab
index c30af029ce..fd1b3b9c74 100644
--- a/erts/emulator/beam/ops.tab
+++ b/erts/emulator/beam/ops.tab
@@ -1578,3 +1578,9 @@ i_recv_mark
 recv_set Fail | label Lbl | loop_rec Lf Reg => \
    i_recv_set | label Lbl | loop_rec Lf Reg
 i_recv_set
+
+#
+# OTP 21.
+#
+
+build_stacktrace
diff --git a/erts/emulator/hipe/hipe_bif2.c b/erts/emulator/hipe/hipe_bif2.c
index 9ebbb22846..df377b2153 100644
--- a/erts/emulator/hipe/hipe_bif2.c
+++ b/erts/emulator/hipe/hipe_bif2.c
@@ -190,3 +190,8 @@ BIF_RETTYPE hipe_bifs_llvm_fix_pinned_regs_0(BIF_ALIST_0)
 {
     BIF_RET(am_ok);
 }
+
+BIF_RETTYPE hipe_bifs_build_stacktrace_1(BIF_ALIST_1)
+{
+    BIF_RET(build_stacktrace(BIF_P, BIF_ARG_1));
+}
diff --git a/erts/emulator/hipe/hipe_bif2.tab b/erts/emulator/hipe/hipe_bif2.tab
index bbcb577be0..c4da44606a 100644
--- a/erts/emulator/hipe/hipe_bif2.tab
+++ b/erts/emulator/hipe/hipe_bif2.tab
@@ -32,3 +32,4 @@ bif hipe_bifs:modeswitch_debug_on/0
 bif hipe_bifs:modeswitch_debug_off/0
 bif hipe_bifs:debug_native_called/2
 bif hipe_bifs:llvm_fix_pinned_regs/0
+bif hipe_bifs:build_stacktrace/1
diff --git a/erts/emulator/hipe/hipe_bif_list.m4 b/erts/emulator/hipe/hipe_bif_list.m4
index 625d8486fd..4f0a655508 100644
--- a/erts/emulator/hipe/hipe_bif_list.m4
+++ b/erts/emulator/hipe/hipe_bif_list.m4
@@ -186,6 +186,7 @@ gc_bif_interface_1(nbif_erase_1, erase_1)
 gc_bif_interface_1(nbif_erts_internal_garbage_collect_1, erts_internal_garbage_collect_1)
 gc_nofail_primop_interface_1(nbif_gc_1, hipe_gc)
 gc_bif_interface_2(nbif_put_2, put_2)
+gc_bif_interface_2(nbif_hipe_bifs_build_stacktrace, hipe_bifs_build_stacktrace_1)
 
 /*
  * Debug BIFs that need read access to the full state.
diff --git a/erts/emulator/hipe/hipe_native_bif.h b/erts/emulator/hipe/hipe_native_bif.h
index d5081b8438..6dffec1d8d 100644
--- a/erts/emulator/hipe/hipe_native_bif.h
+++ b/erts/emulator/hipe/hipe_native_bif.h
@@ -104,6 +104,9 @@ void hipe_emulate_fpe(Process*);
 AEXTERN(void,nbif_emasculate_binary,(Eterm));
 void hipe_emasculate_binary(Eterm);
 
+AEXTERN(BIF_RETTYPE,nbif_hipe_bifs_build_stacktrace,(Process*,Eterm));
+BIF_RETTYPE hipe_bifs_build_stacktrace_1(BIF_ALIST_1);
+
 /*
  * Stuff that is different in SMP and non-SMP.
  */
diff --git a/erts/emulator/hipe/hipe_primops.h b/erts/emulator/hipe/hipe_primops.h
index a6abd3e011..d6fd10bdff 100644
--- a/erts/emulator/hipe/hipe_primops.h
+++ b/erts/emulator/hipe/hipe_primops.h
@@ -83,6 +83,7 @@ PRIMOP_LIST(am_emulate_fpe, &nbif_emulate_fpe)
 #endif
 PRIMOP_LIST(am_emasculate_binary, &nbif_emasculate_binary)
 PRIMOP_LIST(am_debug_native_called, &nbif_hipe_bifs_debug_native_called)
+PRIMOP_LIST(am_build_stacktrace, &nbif_hipe_bifs_build_stacktrace)
 
 #if defined(__sparc__)
 #include "hipe_sparc_primops.h"
diff --git a/erts/emulator/test/binary_SUITE.erl b/erts/emulator/test/binary_SUITE.erl
index c71267a6d1..4bc1838139 100644
--- a/erts/emulator/test/binary_SUITE.erl
+++ b/erts/emulator/test/binary_SUITE.erl
@@ -1472,13 +1472,13 @@ error_after_yield(Type, M, F, AN, AFun, TrapFunc) ->
 					   apply(M, F, A),
 					   exit({unexpected_success, {M, F, A}})
 				       catch
-					   error:Type ->
+					   error:Type:Stk ->
 					       erlang:trace(self(),false,[running,{tracer,Tracer}]),
 					       %% We threw the exception from the native
 					       %% function we trapped to, but we want
 					       %% the BIF that originally was called
 					       %% to appear in the stack trace.
-					       [{M, F, A, _} | _] = erlang:get_stacktrace()
+					       [{M, F, A, _} | _] = Stk
 				       end
 			       end),
     receive
diff --git a/erts/emulator/test/call_trace_SUITE.erl b/erts/emulator/test/call_trace_SUITE.erl
index 1251d644ae..d19f7f81ad 100644
--- a/erts/emulator/test/call_trace_SUITE.erl
+++ b/erts/emulator/test/call_trace_SUITE.erl
@@ -1116,8 +1116,8 @@ get_deep_4_loc(Arg) ->
         deep_4(Arg),
         ct:fail(should_not_return_to_here)
     catch
-        _:_ ->
-            [{?MODULE,deep_4,1,Loc0}|_] = erlang:get_stacktrace(),
+        _:_:Stk ->
+            [{?MODULE,deep_4,1,Loc0}|_] = Stk,
             Loc0
     end.
 
diff --git a/erts/emulator/test/dirty_bif_SUITE.erl b/erts/emulator/test/dirty_bif_SUITE.erl
index c8f0cbf42d..46eb0cba58 100644
--- a/erts/emulator/test/dirty_bif_SUITE.erl
+++ b/erts/emulator/test/dirty_bif_SUITE.erl
@@ -108,90 +108,80 @@ dirty_bif_exception(Config) when is_list(Config) ->
 			      erts_debug:dirty_cpu(error, Error),
 			      ct:fail(expected_exception)
 			  catch
-			      error:ErrorType ->
-				  [{erts_debug,dirty_cpu,[error, Error],_}|_]
-				      = erlang:get_stacktrace(),
+			      error:ErrorType:Stk1 ->
+				  [{erts_debug,dirty_cpu,[error, Error],_}|_] = Stk1,
 				  ok
 			  end,
 			  try
 			      apply(erts_debug,dirty_cpu,[error, Error]),
 			      ct:fail(expected_exception)
 			  catch
-			      error:ErrorType ->
-				  [{erts_debug,dirty_cpu,[error, Error],_}|_]
-				      = erlang:get_stacktrace(),
+			      error:ErrorType:Stk2 ->
+				  [{erts_debug,dirty_cpu,[error, Error],_}|_] = Stk2,
 				  ok
 			  end,
 			  try
 			      erts_debug:dirty_io(error, Error),
 			      ct:fail(expected_exception)
 			  catch
-			      error:ErrorType ->
-				  [{erts_debug,dirty_io,[error, Error],_}|_]
-				      = erlang:get_stacktrace(),
+			      error:ErrorType:Stk3 ->
+				  [{erts_debug,dirty_io,[error, Error],_}|_] = Stk3,
 				  ok
 			  end,
 			  try
 			      apply(erts_debug,dirty_io,[error, Error]),
 			      ct:fail(expected_exception)
 			  catch
-			      error:ErrorType ->
-				  [{erts_debug,dirty_io,[error, Error],_}|_]
-				      = erlang:get_stacktrace(),
+			      error:ErrorType:Stk4 ->
+				  [{erts_debug,dirty_io,[error, Error],_}|_] = Stk4,
 				  ok
 			  end,
 			  try
 			      erts_debug:dirty(normal, error, Error),
 			      ct:fail(expected_exception)
 			  catch
-			      error:ErrorType ->
-				  [{erts_debug,dirty,[normal, error, Error],_}|_]
-				      = erlang:get_stacktrace(),
+			      error:ErrorType:Stk5 ->
+				  [{erts_debug,dirty,[normal, error, Error],_}|_] = Stk5,
 				  ok
 			  end,
 			  try
 			      apply(erts_debug,dirty,[normal, error, Error]),
 			      ct:fail(expected_exception)
 			  catch
-			      error:ErrorType ->
-				  [{erts_debug,dirty,[normal, error, Error],_}|_]
-				      = erlang:get_stacktrace(),
+			      error:ErrorType:Stk6 ->
+				  [{erts_debug,dirty,[normal, error, Error],_}|_] = Stk6,
 				  ok
 			  end,
 			  try
 			      erts_debug:dirty(dirty_cpu, error, Error),
 			      ct:fail(expected_exception)
 			  catch
-			      error:ErrorType ->
-				  [{erts_debug,dirty,[dirty_cpu, error, Error],_}|_]
-				      = erlang:get_stacktrace(),
+			      error:ErrorType:Stk7 ->
+				  [{erts_debug,dirty,[dirty_cpu, error, Error],_}|_] = Stk7,
 				  ok
 			  end,
 			  try
 			      apply(erts_debug,dirty,[dirty_cpu, error, Error]),
 			      ct:fail(expected_exception)
 			  catch
-			      error:ErrorType ->
-				  [{erts_debug,dirty,[dirty_cpu, error, Error],_}|_]
-				      = erlang:get_stacktrace(),
+			      error:ErrorType:Stk8 ->
+				  [{erts_debug,dirty,[dirty_cpu, error, Error],_}|_] = Stk8,
 				  ok
 			  end,
 			  try
 			      erts_debug:dirty(dirty_io, error, Error),
 			      ct:fail(expected_exception)
 			  catch
-			      error:ErrorType ->
-				  [{erts_debug,dirty,[dirty_io, error, Error],_}|_]
-				      = erlang:get_stacktrace(),
+			      error:ErrorType:Stk9 ->
+				  [{erts_debug,dirty,[dirty_io, error, Error],_}|_] = Stk9,
 				  ok
 			  end,
 			  try
 			      apply(erts_debug,dirty,[dirty_io, error, Error]),
 			      ct:fail(expected_exception)
 			  catch
-			      error:ErrorType ->
-				  [{erts_debug,dirty,[dirty_io, error, Error],_}|_]
-				      = erlang:get_stacktrace(),
+			      error:ErrorType:Stk10 ->
+				  [{erts_debug,dirty,[dirty_io, error, Error],_}|_] = Stk10,
 				  ok
 			  end
 		  end,
@@ -204,25 +194,22 @@ dirty_bif_multischedule_exception(Config) when is_list(Config) ->
     try
 	erts_debug:dirty_cpu(reschedule,1001)
     catch
-	error:badarg ->
-	    [{erts_debug,dirty_cpu,[reschedule, 1001],_}|_]
-		= erlang:get_stacktrace(),
+	error:badarg:Stk1 ->
+	    [{erts_debug,dirty_cpu,[reschedule, 1001],_}|_] = Stk1,
 	    ok
     end,
     try
 	erts_debug:dirty_io(reschedule,1001)
     catch
-	error:badarg ->
-	    [{erts_debug,dirty_io,[reschedule, 1001],_}|_]
-		= erlang:get_stacktrace(),
+	error:badarg:Stk2 ->
+	    [{erts_debug,dirty_io,[reschedule, 1001],_}|_] = Stk2,
 	    ok
     end,
     try
 	erts_debug:dirty(normal,reschedule,1001)
     catch
-	error:badarg ->
-	    [{erts_debug,dirty,[normal,reschedule,1001],_}|_]
-		= erlang:get_stacktrace(),
+	error:badarg:Stk3 ->
+	    [{erts_debug,dirty,[normal,reschedule,1001],_}|_] = Stk3,
 	    ok
     end.
 
diff --git a/erts/emulator/test/dirty_nif_SUITE.erl b/erts/emulator/test/dirty_nif_SUITE.erl
index d36113c3e3..93d0ac392c 100644
--- a/erts/emulator/test/dirty_nif_SUITE.erl
+++ b/erts/emulator/test/dirty_nif_SUITE.erl
@@ -109,9 +109,8 @@ dirty_nif_exception(Config) when is_list(Config) ->
 	call_dirty_nif_exception(1),
 	ct:fail(expected_badarg)
     catch
-	error:badarg ->
-	    [{?MODULE,call_dirty_nif_exception,[1],_}|_] =
-		erlang:get_stacktrace(),
+	error:badarg:Stk1 ->
+	    [{?MODULE,call_dirty_nif_exception,[1],_}|_] = Stk1,
 	    ok
     end,
     try
@@ -121,9 +120,8 @@ dirty_nif_exception(Config) when is_list(Config) ->
 	call_dirty_nif_exception(0),
 	ct:fail(expected_badarg)
     catch
-	error:badarg ->
-	    [{?MODULE,call_dirty_nif_exception,[0],_}|_] =
-		erlang:get_stacktrace(),
+	error:badarg:Stk2 ->
+	    [{?MODULE,call_dirty_nif_exception,[0],_}|_] = Stk2,
 	    ok
     end,
     %% this checks that a dirty NIF can raise various terms as
@@ -138,8 +136,8 @@ nif_raise_exceptions(NifFunc) ->
                             erlang:apply(?MODULE,NifFunc,[Term]),
                             ct:fail({expected,Term})
                         catch
-                            error:Term ->
-                                [{?MODULE,NifFunc,[Term],_}|_] = erlang:get_stacktrace(),
+                            error:Term:Stk ->
+                                [{?MODULE,NifFunc,[Term],_}|_] = Stk,
                                 ok
                         end
                 end, ok, ExcTerms).
diff --git a/erts/emulator/test/driver_SUITE.erl b/erts/emulator/test/driver_SUITE.erl
index 475e03087a..6446d5f6d2 100644
--- a/erts/emulator/test/driver_SUITE.erl
+++ b/erts/emulator/test/driver_SUITE.erl
@@ -2614,8 +2614,8 @@ rpc(Config, Fun) ->
                                 Result
                                     = try Fun() of
                                           Res -> Res
-                                      catch E:R ->
-                                              {'EXIT',E,R,erlang:get_stacktrace()}
+                                      catch E:R:Stk ->
+                                              {'EXIT',E,R,Stk}
                                       end,
                                 Self ! {Ref, Result}
                         end),
diff --git a/erts/emulator/test/exception_SUITE.erl b/erts/emulator/test/exception_SUITE.erl
index be9b63d534..da0292f385 100644
--- a/erts/emulator/test/exception_SUITE.erl
+++ b/erts/emulator/test/exception_SUITE.erl
@@ -395,12 +395,12 @@ raise(Conf) when is_list(Conf) ->
     try 
         try foo({'div',{1,0}}) 
         catch
-            error:badarith ->
+            error:badarith:A0 ->
                 put(raise, A0 = erlang:get_stacktrace()),
                 erlang:raise(error, badarith, A0)
         end
     catch
-        error:badarith ->
+        error:badarith:A1 ->
             A1 = erlang:get_stacktrace(),
             A1 = get(raise)
     end,
diff --git a/erts/emulator/test/nif_SUITE.erl b/erts/emulator/test/nif_SUITE.erl
index 2afeb7e4cf..85c302e310 100644
--- a/erts/emulator/test/nif_SUITE.erl
+++ b/erts/emulator/test/nif_SUITE.erl
@@ -2257,9 +2257,8 @@ nif_schedule(Config) when is_list(Config) ->
     {B,A} = call_nif_schedule(A, B),
     ok = try call_nif_schedule(1, 2)
 	 catch
-	     error:badarg ->
-		 [{?MODULE,call_nif_schedule,[1,2],_}|_] =
-		     erlang:get_stacktrace(),
+	     error:badarg:Stk ->
+		 [{?MODULE,call_nif_schedule,[1,2],_}|_] = Stk,
 		 ok
 	 end,
     ok.
@@ -2429,8 +2428,8 @@ nif_raise_exceptions(NifFunc) ->
                             erlang:apply(?MODULE,NifFunc,[Term]),
                             ct:fail({expected,Term})
                         catch
-                            error:Term ->
-                                [{?MODULE,NifFunc,[Term],_}|_] = erlang:get_stacktrace(),
+                            error:Term:Stk ->
+                                [{?MODULE,NifFunc,[Term],_}|_] = Stk,
                                 ok
                         end
                 end, ok, ExcTerms).