<html><head><base href="x-msg://1032/"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">I think we need to have a way to get the scope of the containing procedure.<div>TryStmt.Parse is not the right place.</div><div>If I get some time soon I can take a look at this.<br>
<br><div><div>On Jan 31, 2011, at 2:19 PM, Jay K wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><span class="Apple-style-span" style="border-collapse: separate; font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div class="hmmessage" style="font-size: 10pt; font-family: Tahoma; ">Right..I also tried Scope.Insert, didn't seem to help.<br> <br>But I think I might be doing it too late. I'll try doing it in Parse instead of Check.<br>Though I don't recall if Parse knows enough -- if it knows if CaptureState will be called.<br>I agree/disagree about alloca up front, with the obvious reasons -- it is smaller code to alloca up front, and it somewhat<br>more closely resembles the old pattern:<br> <br>IF Foo() THEN<br> RETURN<br>ELSE TRY FINALLY<br> <br>in the old way would use the stack, so we could too.<br>But the allocation is slower/larger now (alloca possibly aligning up more than needed).<br>Anyway, this point isn't the problem. The problem is my inability to work with m3front.<br>I'll look at it a bit more -- i.e. as I said, moving the code to Parse.<br> <br>The other improvement I'd like to make:<br> <br>currently, if I had it working, what I'm aiming for is:<br>struct EF1{ ... jmpbuf* jb } ef1;<br>jmpbuf* jb = 0;<br> <br>jb = jb ? jb : alloca(sizeof(*jb));<br>ef1.jb = jb;<br>setjmp(ef1.jb);<br> <br>but it'd be better to have:<br> <br>struct EF1{ ... jmpbuf* jb } ef1;<br>ef1.jb = 0;<br> <br>ef1.jb = ef1.jb ? ef1.jb : alloca(sizeof(*jb));<br>setjmp(ef1.jb);<br> <br> <br>ie. we don't need the extra pointer variable, the pointer in the record should suffice.<br> <br> <br>[not sure where to put this in email]<br> I tried figuring out how to determine the current vs. topmost-in-current-function scope.<br> I'm not sure if Scope.Top is about in a function or if it is module scope, or even perhaps<br> some outside-all-modules scope. But Scope.Insert doesn't let you specify a scope,<br> so I kinda hoped it'd just use the correct scope.<br> <br> <br>Anyway, I'll look again at introducing the Variable.New and Scope.Insert during Parse.<br>Even if it doesn't get used, that might be ok, since there is tracking of use, and<br>declaring it might not cause any waste if it isn't used.<br> <br> <br>Thanks,<br> - Jay<br><br> <br><hr id="stopSpelling">From:<span class="Apple-converted-space"> </span><a href="mailto:hosking@cs.purdue.edu">hosking@cs.purdue.edu</a><br>Date: Mon, 31 Jan 2011 12:14:09 -0500<br>To:<span class="Apple-converted-space"> </span><a href="mailto:jay.krell@cornell.edu">jay.krell@cornell.edu</a><br>CC:<span class="Apple-converted-space"> </span><a href="mailto:m3devel@elegosoft.com">m3devel@elegosoft.com</a><br>Subject: Re: [M3devel] fixing try/setjmp in a loop?<br><br>Hi Jay,<div><br></div><div>I've not had a chance to digest this, but I do understand the problem. We need the Variable to be entered into the outermost scope of the procedure in which the TRY appears so that it will have initialization code (assigning NIL) generated for it on entry to the procedure. Then your usage of the variable should simply check for NIL and alloca if it is, as you already appear to do here. It would be possible to have the initialization code perform the alloca but then we would have an alloca for every TRY block in a procedure even if they never execute. Probably not the best plan.</div><div><br><div><span class="ecxApple-style-span" style="text-transform: none; text-indent: 0px; border-collapse: separate; font: normal normal normal 12px/normal Helvetica; white-space: normal; letter-spacing: normal; color: rgb(0, 0, 0); word-spacing: 0px; "><span class="ecxApple-style-span" style="text-transform: none; text-indent: 0px; border-collapse: separate; font: normal normal normal 12px/normal Helvetica; white-space: normal; letter-spacing: normal; color: rgb(0, 0, 0); word-spacing: 0px; "><div style="word-wrap: break-word; "><span class="ecxApple-style-span" style="text-transform: none; text-indent: 0px; border-collapse: separate; font: normal normal normal 12px/normal Helvetica; white-space: normal; letter-spacing: normal; color: rgb(0, 0, 0); word-spacing: 0px; "><span class="ecxApple-style-span" style="text-transform: none; text-indent: 0px; border-collapse: separate; font: normal normal normal 12px/normal Helvetica; white-space: normal; letter-spacing: normal; color: rgb(0, 0, 0); word-spacing: 0px; "><span class="ecxApple-style-span" style="text-transform: none; text-indent: 0px; border-collapse: separate; font: normal normal normal 12px/normal Helvetica; white-space: normal; letter-spacing: normal; color: rgb(0, 0, 0); word-spacing: 0px; "><span class="ecxApple-style-span" style="text-transform: none; text-indent: 0px; border-collapse: separate; font: normal normal normal 12px/normal Helvetica; white-space: normal; letter-spacing: normal; color: rgb(0, 0, 0); word-spacing: 0px; "><span class="ecxApple-style-span" style="text-transform: none; text-indent: 0px; border-collapse: separate; font: normal normal normal 12px/normal Helvetica; white-space: normal; letter-spacing: normal; color: rgb(0, 0, 0); word-spacing: 0px; "><span class="ecxApple-style-span" style="text-transform: none; text-indent: 0px; border-collapse: separate; font: normal normal normal 12px/normal Helvetica; white-space: normal; letter-spacing: normal; color: rgb(0, 0, 0); word-spacing: 0px; "><span class="ecxApple-style-span" style="text-transform: none; text-indent: 0px; border-collapse: separate; font: normal normal normal 12px/normal Helvetica; white-space: normal; letter-spacing: normal; color: rgb(0, 0, 0); word-spacing: 0px; "><span class="ecxApple-style-span" style="text-transform: none; text-indent: 0px; border-collapse: separate; font: normal normal normal 12px/normal Helvetica; white-space: normal; letter-spacing: normal; color: rgb(0, 0, 0); word-spacing: 0px; "><div><font class="ecxApple-style-span" color="#0000ff"><font class="ecxApple-style-span" face="Gill Sans"><span class="ecxApple-style-span" style="font-family: 'Gill Sans'; color: rgb(0, 0, 255); "><span class="ecxApple-style-span" style="font-family: 'Gill Sans'; color: rgb(0, 0, 255); ">Antony Hosking</span></span></font></font><font class="ecxApple-style-span" face="Gill Sans"><span class="ecxApple-style-span" style="font-family: 'Gill Sans'; "><span class="ecxApple-style-span" style="font-family: 'Gill Sans'; "><span class="ecxApple-converted-space"> </span>|<span class="ecxApple-converted-space"> </span></span></span><span class="ecxApple-style-span" style="font-family: 'Gill Sans'; "><span class="ecxApple-style-span" style="font-family: 'Gill Sans'; ">Associate Professor</span></span><span class="ecxApple-style-span" style="font-family: 'Gill Sans'; "><span class="ecxApple-style-span" style="font-family: 'Gill Sans'; "> | Computer Science | Purdue University</span></span></font></div><div><font class="ecxApple-style-span" face="GillSans-Light"><span class="ecxApple-style-span" style="font-family: GillSans-Light; ">305 N. 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But this doesn't work. What am I missing?<br>And, we should go the next step and merge the jmpbuf pointer variable with the jmpbuf field in the EF1, right?<br><br><br>? 1.txt<br>Index: src/misc/Marker.i3<br>===================================================================<br>RCS file: /usr/cvs/cm3/m3-sys/m3front/src/misc/Marker.i3,v<br>retrieving revision 1.1.1.1<br>diff -u -r1.1.1.1 Marker.i3<br>--- src/misc/Marker.i3 14 Jan 2001 13:40:31 -0000 1.1.1.1<br>+++ src/misc/Marker.i3 30 Jan 2011 10:41:18 -0000<br>@@ -64,9 +64,12 @@<br> PROCEDURE SetLock (acquire: BOOLEAN; var: CG.Var; offset: INTEGER);<br> (* generate the call to acquire or release a mutex *)<br> <br>-PROCEDURE CaptureState (frame: CG.Var; handler: CG.Label);<br>+PROCEDURE CaptureState (frame: CG.Var; handler: CG.Label;<br>+ jumpbuf: Variable.T);<br> (* call 'setjmp' on 'frame's jmpbuf and branch to 'handler' on re-returns. *)<br> <br> PROCEDURE Reset ();<br> <br>+PROCEDURE NewJumpbuf (): Variable.T;<br>+<br> END Marker.<br>Index: src/misc/Marker.m3<br>===================================================================<br>RCS file: /usr/cvs/cm3/m3-sys/m3front/src/misc/Marker.m3,v<br>retrieving revision 1.9<br>diff -u -r1.9 Marker.m3<br>--- src/misc/Marker.m3 13 Jan 2011 14:58:28 -0000 1.9<br>+++ src/misc/Marker.m3 30 Jan 2011 10:41:18 -0000<br>@@ -10,7 +10,7 @@<br> MODULE Marker;<br> <br> IMPORT CG, Error, Type, Variable, ProcType, ESet, Expr, AssignStmt;<br>-IMPORT M3ID, M3RT, Target, Module, RunTyme, Procedure, Host;<br>+IMPORT M3ID, M3RT, Target, Module, RunTyme, Procedure, Host, Addr;<br> <br> TYPE<br> Kind = { zFINALLY, zFINALLYPROC, zLOCK, zEXIT, zTRY, zTRYELSE,<br>@@ -231,8 +231,10 @@<br> END;<br> END CallFinallyHandler;<br> <br>-PROCEDURE CaptureState (frame: CG.Var; handler: CG.Label) =<br>+PROCEDURE CaptureState (frame: CG.Var; handler: CG.Label;<br>+ jumpbuf: Variable.T) =<br> VAR new: BOOLEAN;<br>+ label := CG.Next_label ();<br> BEGIN<br> (* int setjmp(void* ); *)<br> IF (setjmp = NIL) THEN<br>@@ -262,13 +264,33 @@<br> Target.Word.size, Target.Word.align,<br> Target.Word.cg_type, 0);<br> END;<br>- <span class="ecxApple-converted-space"> </span><br>- (* frame.jmpbuf = alloca(Csetjmp__Jumpbuf_size); *)<br>+<br>+ (* IF jumpuf # NIL THEN <span class="ecxApple-converted-space"> </span><br>+ * frame.jmpbuf = alloca(Csetjmp__Jumpbuf_size);<br>+ * END<br>+ *)<br>+<br>+ CG.Load_nil ();<br>+ Variable.Load (jumpbuf);<br>+ CG.If_compare (CG.Type.Addr, CG.Cmp.NE, label, CG.Maybe);<br>+<br> CG.Start_call_direct (alloca, 0, Target.Address.cg_type);<br> CG.Load_int (Target.Word.cg_type, Jumpbuf_size);<br> CG.Pop_param (Target.Word.cg_type);<br> CG.Call_direct (alloca, Target.Address.cg_type);<br>+<br>+ (* FUTURE: We should actually have a Variable<br>+ * for the entire EF1, including initializing the jumpbuf<br>+ * in it. That would save us this extra load/store,<br>+ * and save a local variable.<br>+ *)<br>+ Variable.LoadLValue (jumpbuf);<br>+ CG.Swap ();<br>+ CG.Store_indirect (CG.Type.Addr, 0, Target.Address.size);<br>+ Variable.Load (jumpbuf);<br>+<br> CG.Store_addr (frame, M3RT.EF1_jmpbuf);<br>+ CG.Set_label (label);<br> <br> (* setmp(frame.jmpbuf) *)<br> CG.Start_call_direct (setjmp, 0, Target.Integer.cg_type);<br>@@ -806,5 +828,15 @@<br> tos := 0;<br> END Reset;<br> <br>+PROCEDURE NewJumpbuf (): Variable.T =<br>+ VAR jumpbuf: Variable.T;<br>+ BEGIN<br>+ jumpbuf := Variable.New (M3ID.NoID, TRUE);<br>+ Variable.BindType (jumpbuf, Addr.T, indirect := FALSE,<br>+ readonly := FALSE, open_array_ok := FALSE,<br>+ needs_init := TRUE);<br>+ RETURN jumpbuf;<br>+ END NewJumpbuf;<br>+<br> BEGIN<br> END Marker.<br>Index: src/stmts/TryFinStmt.m3<br>===================================================================<br>RCS file: /usr/cvs/cm3/m3-sys/m3front/src/stmts/TryFinStmt.m3,v<br>retrieving revision 1.6<br>diff -u -r1.6 TryFinStmt.m3<br>--- src/stmts/TryFinStmt.m3 5 Jan 2011 14:34:54 -0000 1.6<br>+++ src/stmts/TryFinStmt.m3 30 Jan 2011 10:41:18 -0000<br>@@ -10,6 +10,7 @@<br> <br> IMPORT M3ID, CG, Token, Scanner, Stmt, StmtRep, Marker, Target, Type, Addr;<br> IMPORT RunTyme, Procedure, ProcBody, M3RT, Scope, Fmt, Host, TryStmt, Module;<br>+IMPORT Variable;<br> FROM Stmt IMPORT Outcome;<br> <br> TYPE<br>@@ -20,6 +21,7 @@<br> viaProc : BOOLEAN;<br> scope : Scope.T;<br> handler : HandlerProc;<br>+ jumpbuf : Variable.T := NIL;<br> OVERRIDES<br> check := Check;<br> compile := Compile;<br>@@ -63,6 +65,11 @@<br> RETURN p;<br> END Parse;<br> <br>+PROCEDURE UsesSetjmp (p: P): BOOLEAN =<br>+ BEGIN<br>+ RETURN NOT (Target.Has_stack_walker OR p.viaProc);<br>+ END UsesSetjmp;<br>+<br> PROCEDURE Check (p: P; VAR cs: Stmt.CheckState) =<br> VAR zz: Scope.T; oc: Stmt.Outcomes; name: INTEGER;<br> BEGIN<br>@@ -95,6 +102,9 @@<br> END;<br> END;<br> TryStmt.PopHandler ();<br>+ IF UsesSetjmp (p) THEN<br>+ p.jumpbuf := Marker.NewJumpbuf ();<br>+ END;<br> END Check;<br> <br> PROCEDURE HandlerName (uid: INTEGER): TEXT =<br>@@ -106,11 +116,16 @@<br> END HandlerName;<br> <br> PROCEDURE Compile (p: P): Stmt.Outcomes =<br>+ VAR usesSetjmp := FALSE;<br>+ result: Stmt.Outcomes;<br> BEGIN<br>- IF Target.Has_stack_walker THEN RETURN Compile1 (p);<br>- ELSIF p.viaProc THEN RETURN Compile2 (p);<br>- ELSE RETURN Compile3 (p);<br>+ IF Target.Has_stack_walker THEN result := Compile1 (p);<br>+ ELSIF p.viaProc THEN result := Compile2 (p);<br>+ ELSE usesSetjmp := TRUE;<br>+ result := Compile3 (p);<br> END;<br>+ <* ASSERT usesSetjmp = UsesSetjmp (p) *><br>+ RETURN result;<br> END Compile;<br> <br> PROCEDURE Compile1 (p: P): Stmt.Outcomes =<br>@@ -302,7 +317,9 @@<br> l := CG.Next_label (3);<br> CG.Set_label (l, barrier := TRUE);<br> Marker.PushFrame (frame, M3RT.HandlerClass.Finally);<br>- Marker.CaptureState (frame, l+1);<br>+ <* ASSERT UsesSetjmp (p) *><br>+ <* ASSERT p.jumpbuf # NIL *><br>+ Marker.CaptureState (frame, l+1, p.jumpbuf);<br> <br> (* compile the body *)<br> Marker.PushFinally (l, l+1, frame);<br>Index: src/stmts/TryStmt.m3<br>===================================================================<br>RCS file: /usr/cvs/cm3/m3-sys/m3front/src/stmts/TryStmt.m3,v<br>retrieving revision 1.3<br>diff -u -r1.3 TryStmt.m3<br>--- src/stmts/TryStmt.m3 5 Jan 2011 14:34:54 -0000 1.3<br>+++ src/stmts/TryStmt.m3 30 Jan 2011 10:41:18 -0000<br>@@ -22,6 +22,7 @@<br> hasElse : BOOLEAN;<br> elseBody : Stmt.T;<br> handled : ESet.T;<br>+ jumpbuf : Variable.T := NIL;<br> OVERRIDES<br> check := Check;<br> compile := Compile;<br>@@ -153,6 +154,14 @@<br> p.handles := h3;<br> END ReverseHandlers;<br> <br>+PROCEDURE UsesSetjmp (p: P): BOOLEAN =<br>+ BEGIN<br>+ IF (p.handles = NIL) AND (NOT p.hasElse) THEN<br>+ RETURN FALSE;<br>+ END;<br>+ RETURN NOT Target.Has_stack_walker;<br>+ END UsesSetjmp;<br>+<br> PROCEDURE Check (p: P; VAR cs: Stmt.CheckState) =<br> VAR h: Handler; handled: ESet.T;<br> BEGIN<br>@@ -182,6 +191,10 @@<br> WHILE (h # NIL) DO CheckHandler (h, cs); h := h.next; END;<br> Stmt.TypeCheck (p.elseBody, cs);<br> PopHandler ();<br>+<br>+ IF UsesSetjmp (p) THEN<br>+ p.jumpbuf := Marker.NewJumpbuf ();<br>+ END;<br> END Check;<br> <br> PROCEDURE CheckLabels (h: Handler; scope: Scope.T; VAR cs: Stmt.CheckState) =<br>@@ -245,14 +258,19 @@<br> END CheckHandler;<br> <br> PROCEDURE Compile (p: P): Stmt.Outcomes =<br>+ VAR usesSetjmp := FALSE;<br>+ result: Stmt.Outcomes;<br> BEGIN<br> IF (p.handles = NIL) AND (NOT p.hasElse) THEN<br>- RETURN Stmt.Compile (p.body);<br>- END;<br>- IF Target.Has_stack_walker<br>- THEN RETURN Compile1 (p);<br>- ELSE RETURN Compile2 (p);<br>+ result := Stmt.Compile (p.body);<br>+ ELSIF Target.Has_stack_walker THEN<br>+ result := Compile1 (p);<br>+ ELSE<br>+ usesSetjmp := TRUE;<br>+ result := Compile2 (p);<br> END;<br>+ <* ASSERT usesSetjmp = UsesSetjmp (p) *><br>+ RETURN result;<br> END Compile;<br> <br> PROCEDURE Compile1 (p: P): Stmt.Outcomes =<br>@@ -423,7 +441,9 @@<br> END;<br> <br> (* capture the machine state *)<br>- Marker.CaptureState (frame, l+1);<br>+ <* ASSERT UsesSetjmp (p) *><br>+ <* ASSERT p.jumpbuf # NIL *><br>+ Marker.CaptureState (frame, l+1, p.jumpbuf);<br> <br> (* compile the body *)<br> oc := Stmt.Compile (p.body);<br><br>Thanks,<br> - Jay<br></div></span></blockquote></div><br></div></div></span><br class="Apple-interchange-newline"></blockquote></div><br></div></body></html>