digitalmars.D.bugs - [Issue 12163] New: pdb debugging (win64): stepping loops points to incorrect lines
- d-bugmail puremagic.com (96/96) Feb 14 2014 https://d.puremagic.com/issues/show_bug.cgi?id=12163
- d-bugmail puremagic.com (14/14) Feb 15 2014 https://d.puremagic.com/issues/show_bug.cgi?id=12163
- d-bugmail puremagic.com (11/11) Feb 15 2014 https://d.puremagic.com/issues/show_bug.cgi?id=12163
- d-bugmail puremagic.com (12/12) Feb 15 2014 https://d.puremagic.com/issues/show_bug.cgi?id=12163
- d-bugmail puremagic.com (30/30) Feb 15 2014 https://d.puremagic.com/issues/show_bug.cgi?id=12163
- d-bugmail puremagic.com (10/12) Feb 15 2014 https://d.puremagic.com/issues/show_bug.cgi?id=12163
- d-bugmail puremagic.com (19/20) Feb 15 2014 https://d.puremagic.com/issues/show_bug.cgi?id=12163
- d-bugmail puremagic.com (11/15) Feb 15 2014 https://d.puremagic.com/issues/show_bug.cgi?id=12163
https://d.puremagic.com/issues/show_bug.cgi?id=12163 Summary: pdb debugging (win64): stepping loops points to incorrect lines Product: D Version: D2 Platform: x86_64 OS/Version: Windows Status: NEW Severity: major Priority: P2 Component: DMD AssignedTo: nobody puremagic.com ReportedBy: turkeyman gmail.com This is extremely annoying, and really hinders the DMD debugging experience. Example program: 0 void main() 1 { 2 int[] things = [1,2,3,4]; 3 4 foreach(i; things) 5 { 6 if(i == 2) 7 continue; 8 9 if(i != 3) 10 { 11 int x = 0; 12 } 13 } 14 15 int last = 0; 16 } Compile this for Win64, in VisualD, place a breakpoint on line 2, and begin debugging. Single-step through the program and watch the cursor carefully as it moves; the cursor movement is very confusing. While stepping (using only F10), the program execution is as follows: 2 int[] things = [1,2,3,4]; 4 foreach(i; things) 6 if(i == 2) ; false 9 if(i != 3) ; false 11 int x = 0; ; WRONG! within if(false), should be 13 4 foreach(i; things) 6 if(i == 2) ; true ; MISSING: should step to 7 (continue;) 11 int x = 0; ; WRONG! within if(false), should be 13 4 foreach(i; things) 6 if(i == 2) ; false 9 if(i != 3) ; true 11 int x = 0; ; MISSING: should step to 13 4 foreach(i; things) 6 if(i == 2) ; false 9 if(i != 3) ; false 11 int x = 0; ; WRONG! within if(false), should be 13 4 foreach(i; things) 15 int last = 0; The flow should be: 2 int[] things = [1,2,3,4]; 4 foreach(i; things) 6 if(i == 2) 9 if(i != 3) 13 } 4 foreach(i; things) 6 if(i == 2) 7 continue; 13 } 4 foreach(i; things) 6 if(i == 2) 9 if(i != 3) 11 int x = 0; 13 } 4 foreach(i; things) 6 if(i == 2) 9 if(i != 3) 13 } 4 foreach(i; things) 15 int last = 0; It seems the debug info is writing the last meaningful line of the loop regardless of it's nested depth, instead of the line of the closing '}' at the end of each loop iteration. This is very confusing when stepping complex constructs with deep nested content. It is also important to be able to place a breakpoint on the closing '}' to catch a final opportunity to inspect the values within the loop iteration before the next iteration begins. Currently, the 'continue' line seems to just be skipped. The execution should move there before jumping to the closing '}' so you can place breakpoints allowing to inspect the loop iteration values that caused the case. Without proper cursor movement, it's impossible to place breakpoints to inspect the state that leads to many situations; one of the most important tasks for a debugger. -- Configure issuemail: https://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Feb 14 2014
d-bugmail puremagic.com https://d.puremagic.com/issues/show_bug.cgi?id=12163 Rainer Schuetze <r.sagitario gmx.de> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |r.sagitario gmx.de Platform|x86_64 |All PST --- It's the same for win32, I suspect it is similar with DWARF output. The reason probably is that there is no line number info for the closing braces. The patch to create lexical scope might help here: https://github.com/D-Programming-Language/dmd/pull/2867 -- Configure issuemail: https://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Feb 15 2014
https://d.puremagic.com/issues/show_bug.cgi?id=12163 yazan.dabain gmail.com changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |yazan.dabain gmail.com OS/Version|Windows |All The same behavior can be observed on Linux with DWARF symbols. -- Configure issuemail: https://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Feb 15 2014
https://d.puremagic.com/issues/show_bug.cgi?id=12163 Manu <turkeyman gmail.com> changed: What |Removed |Added ---------------------------------------------------------------------------- Severity|major |critical Right, so it seems it's a line numbering thing rather than a win64/pdb thing. I think that calls for a bump in priority if debugging experience on all platforms is crooked. -- Configure issuemail: https://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Feb 15 2014
https://d.puremagic.com/issues/show_bug.cgi?id=12163 Ohh, your expected output is incorrect. The test is (i != 3) not (i == 3). And so, the expected output is: 2 int[] things = [1,2,3,4]; 4 foreach(i; things) 6 if(i == 2) 9 if(i != 3) 11 int x = 0; 13 } <-- missing/questionable 4 foreach(i; things) 6 if(i == 2) 7 continue; <-- missing 13 } <-- missing/questionable 4 foreach(i; things) 6 if(i == 2) 9 if(i != 3) 13 } <-- missing/questionable 4 foreach(i; things) 6 if(i == 2) 9 if(i != 3) 11 int x = 0; 13 } <-- missing/questionable 4 foreach(i; things) 15 int last = 0; 16 } -- Configure issuemail: https://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Feb 15 2014
https://d.puremagic.com/issues/show_bug.cgi?id=12163Ohh, your expected output is incorrect. The test is (i != 3) not (i == 3).Haha, true. Yeah sorry about that. Perfect example of how the existing debugging experience is broken and doesn't do it right :P I had to type my expectation by hand, and couldn't test it... -- Configure issuemail: https://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Feb 15 2014
https://d.puremagic.com/issues/show_bug.cgi?id=1216313 } <-- missing/questionableI should add, I don't think this is questionable at all. All C compiler's I've ever used (many!) do this, and without it, it would be impossible to place a breakpoint on the last line of the loop, which is a very important tool. The reason you want to place a breakpoint on the closing '}' is so you have a final opportunity to inspect the state of all variables within that cycle of the loop. If the last operation in the loop skipped right into the next cycle of the loop, you would have nowhere you are able to break to inspect the result of that operation. It's obvious that DMD already does have a moment where it intends to step to the 'end of the loop cycle', except rather than pointing to the '}', it incorrectly points to the last significant line in the code, no matter how deeply nested it happens to be. -- Configure issuemail: https://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Feb 15 2014
https://d.puremagic.com/issues/show_bug.cgi?id=12163 yebblies <yebblies gmail.com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |yebblies gmail.comIt's obvious that DMD already does have a moment where it intends to step to the 'end of the loop cycle', except rather than pointing to the '}', it incorrectly points to the last significant line in the code, no matter how deeply nested it happens to be.Yeah, it simply doesn't know where the end of the loop is. -- Configure issuemail: https://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Feb 15 2014