Re: Some observations building gnuplot for win by gcc-4.9.2 (MinGW64)

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On Wednesday, 04 March 2015 09:54:08 AM Tatsuro MATSUOKA wrote:
> 
> ----- Original Message -----
> >From: Ethan A Merritt 
> >To: gnuplot-beta@ Tatsuro MATSUOKA 
> >Date: 2015/3/4, Wed 05:29
> >Subject: Re: Some observations building gnuplot for win by gcc-4.9.2 (MinGW64)
> > 
> >
> > 
> >On Tuesday, 03 March, 2015 16:16:01 Tatsuro MATSUOKA wrote:
> >> Hello
> >> 
> >> I have tried to update gcc for windows build of gnuplot from ver. 4.9.0 to 4.9.2.
> >> Some observations happened for both 64 bit and 32 bit build.
> >> 
> >> 
> >> Complier gcc-4.9.2-2 from MinGW-64 project
> >> 64 bit : exception:seh, thread:win32 
> >> 32 bit : exception:dwarf2, thread:win32 
> >> 
> >> Good point
> >> 
> >>  I can built gd-2.1.1 flawlessly for both 64 bit and 32 bit platform.
> >> 
> >> 
> >> Troubles ?
> >> **********
> >> 64 bit
> >> **********
> >[snip]
> > 
> >> 32 bit
> >> ******
> >> gnuplot crashes by segmentation fault when one use cairo based terminals.
> >> 
> >> Segmentation fault : g_utf8_validate gutf8.c:1634 on MinGW-64 32 bit gcc-4.9.2
> >> 
> >> I have met a  Segmentation fault at using gnuplot-5.1 built by myself on windows.
> >> The Segmentation fault seems to be related with the cairo based terminals.
> >> (The cairo based terminals use libglib.)
> >> 
> >> Compiler gcc-4.9.2 (MinGW-w64 32bit. dwarf, win32 thread).
> >> Glib version : 2.42.1. Build from source.
> >> 
> >> gdb message:
> >> 
> >> Program received signal SIGSEGV, Segmentation fault.
> >> 0x6862318f in g_utf8_validate (str=0x2888a68 "-1", max_len=-1, end=0xffffffff)
> >>     at ../../glib-2.42.1/glib/gutf8.c:1634
> >> 1634        *end = p;
> >> 
> >> Program received signal SIGSEGV, Segmentation fault.
> >> 0x6862318f in g_utf8_validate (str=0xb28a68 "-1", max_len=-1, end=0xffffffff)
> >>     at ../../glib-2.42.1/glib/gutf8.c:1634
> >> 1634        *end = p;
> >> 
> >> 
> >> Perhaps this is a bug of glib (2.42.1 and 2.33.14).
> >> 
> >> I have filed the issue to  the bug tracker of Gnome.
> >>  
> >> https://bugzilla.gnome.org/show_bug.cgi?id=745485
> >> 
> >> At this moment, I abandon the complier update. However, is the trouble 2 for 64 bit case not a issue of gnuplot code?
> > 
> >That is possible.
> >Can you provide a more complete trace of the segfault that
> >shows where in the gnuplot code this failure happened?
> > 
> >Ethan
> > 
> 
> 
> Thank you for your response:
> 
> I copy the back trace.

> For wxt terminal,
> (gdb) bt
> #0  0x6862318f in g_utf8_validate (str=0x2a97fc8 "-1", max_len=-1,
>     end=0xffffffff) at ../../glib-2.42.1/glib/gutf8.c:1634
> #1  0x00529d21 in gp_cairo_convert (plot=0x2a0e0f0, string=0x2a97fc8 "-1")
>     at ../../src/wxterminal/gp_cairo.c:737

[snip]

I think this indicates a bug in glib.
Gnuplot is prepared for an error return from the call to g_utf8_validate,
but apparently glib faults instead of cleanly returning an error.
The gnuplot code is:
        if (g_utf8_validate(string, -1, NULL)) {
            string_utf8 = g_strdup(string);
        } else {
            charset = gp_cairo_get_encoding(plot);
            string_utf8 = g_convert(string, -1, "UTF-8", charset, &bytes_read, NULL, &error);
        }

The strange thing is that the string being converted seems totally
harmless: "-1".   I could more easily understand if the failure
occurred for a string in, for example, SHIFT_JIS encoding since 
I imagine the glib people have not tested that extensively.

The only thing I can think of to try in the gnuplot code is to invert
the order of the tests.  Something like

        charset = gp_cairo_get_encoding(plot);
        if (<some test on charset != UTF8>) {
            string_utf8 = g_convert(string, -1, "UTF-8", charset, &bytes_read, NULL, &error);
        } else if (g_utf8_validate(string, -1, NULL)) {
            string_utf8 = g_strdup(string);
        } else {
            more serious error code or failure
        }

I am not sure what are the proper test in the pseudo-code above
when run on Windows.

	Ethan

> #2  0x0052b6bc in gp_cairo_enhanced_flush (plot=0x2a0e0f0)
>     at ../../src/wxterminal/gp_cairo.c:1311
> #3  0x00525eb9 in wxtPanel::wxt_cairo_exec_command (this=0x2a0df40,
>     command=...) at ../../src/wxterminal/wxt_gui.cpp:2964
> #4  0x005257a9 in wxtPanel::wxt_cairo_refresh (this=0x2a0df40)
>     at ../../src/wxterminal/wxt_gui.cpp:2850
> #5  0x00523e67 in wxt_text () at ../../src/wxterminal/wxt_gui.cpp:2047
> #6  0x0045d368 in wxt_text_wrapper () at ../../term/wxt.trm:460
> #7  0x0040e560 in term_end_plot () at ../../src/term.c:544
> #8  0x004f2f8f in do_plot (plots=0x29f8520, pcount=1)
>     at ../../src/graphics.c:912
> #9  0x004c324e in eval_plots () at ../../src/plot2d.c:3333
> #10 0x004b4ac5 in plotrequest () at ../../src/plot2d.c:271
> #11 0x004acb3d in plot_command () at ../../src/command.c:1535
> #12 0x004aacb8 in command () at ../../src/command.c:621
> #13 0x004aa58d in do_line () at ../../src/command.c:418
> #14 0x004aa2cd in com_line () at ../../src/command.c:322
> #15 0x004b1518 in gnu_main (argc=0, argv=0x29e5818) at ../../src/plot.c:660
> #16 0x0053545b in WinMain@16 (hInstance=0x400000, hPrevInstance=0x0,
>     lpszCmdLine=0xa959c9 "", nCmdShow=10) at ../../src/win/winmain.c:593
> #17 0x0057a31d in main ()
> 
> 
> For pngcairo terminal
> (gdb) bt
> #0  0x6862318f in g_utf8_validate (str=0x28f596 "-1", max_len=-1,
>     end=0xffffffff) at ../../glib-2.42.1/glib/gutf8.c:1634
> #1  0x00529d21 in gp_cairo_convert (plot=0x6088c0 <plot>,
>     string=0x28f596 "-1") at ../../src/wxterminal/gp_cairo.c:737
> #2  0x00529fbd in gp_cairo_draw_text (plot=0x6088c0 <plot>, x1=1100, y1=8842,
>     string=0x28f596 "-1", width=0x0, height=0x0)
>     at ../../src/wxterminal/gp_cairo.c:850
> #3  0x0045f1ab in cairotrm_put_text (x=1100, y=758, string=0x28f596 "-1")
>     at ../../term/cairo.trm:989
> #4  0x0040e9fc in write_multiline (x=1100, y=758, text=0x28f596 "-1",
>     hor=RIGHT, vert=JUST_CENTRE, angle=0, font=0x0) at ../../src/term.c:781
> #5  0x004fd5d5 in ytick2d_callback (axis=FIRST_Y_AXIS, place=-1,
>     text=0x28f596 "-1", ticlevel=0, grid=..., userlabels=0x0)
>     at ../../src/graphics.c:3446
> #6  0x0047fb09 in gen_tics (axis=FIRST_Y_AXIS,
>     callback=0x4fcff4 <ytick2d_callback>) at ../../src/axis.c:1274
> #7  0x00480603 in axis_output_tics (axis=FIRST_Y_AXIS,
>     ticlabel_position=0x60bbac <ytic_x>, zeroaxis_basis=FIRST_X_AXIS,
>     callback=0x4fcff4 <ytick2d_callback>) at ../../src/axis.c:1484
> #8  0x004f11c4 in place_grid () at ../../src/graphics.c:217
> #9  0x004f21a1 in do_plot (plots=0xde86f0, pcount=1)
>     at ../../src/graphics.c:551
> #10 0x004c324e in eval_plots () at ../../src/plot2d.c:3333
> #11 0x004b4ac5 in plotrequest () at ../../src/plot2d.c:271
> #12 0x004acb3d in plot_command () at ../../src/command.c:1535
> #13 0x004aacb8 in command () at ../../src/command.c:621
> #14 0x004aa58d in do_line () at ../../src/command.c:418
> #15 0x004aa2cd in com_line () at ../../src/command.c:322
> #16 0x004b1518 in gnu_main (argc=0, argv=0xdd5818) at ../../src/plot.c:660
> #17 0x0053545b in WinMain@16 (hInstance=0x400000, hPrevInstance=0x0,
>     lpszCmdLine=0x8a59c9 "", nCmdShow=10) at ../../src/win/winmain.c:593
> #18 0x0057a31d in main ()
> (gdb)
> 

Re: Some observations building gnuplot for win by gcc-4.9.2 (MinGW64)

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Re: Some observations building gnuplot for win by gcc-4.9.2 (MinGW64)