Janvier 2016 - Gambit-list - mailman.iro.umontreal.ca

How do you use "___print_ctrl_flow_history" in GDB - where do you get the ___ps from?
by Adam 21 Jan '16

21 Jan '16

Dear Marc, How do I actually run "___print_ctrl_flow_history" from a GDB prompt such as the one below? I have access to global vars, can I pick up the needed ___ps argument from there, or do I need to make an own facility for knowing what ___ps value to use here? E.g. "call ___print_ctrl_flow_history(123456 )" Thanks! $ gdb ./gsc/gsc GNU gdb (GDB) 7.4.1-debian Copyright (C) 2012 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html > This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-linux-gnu". For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>... Reading symbols from /tmp/gambit/gsc/gsc...done. (gdb) run Starting program: /tmp/gambit/gsc/gsc Gambit v4.8.3 > 1 2 3 1 > 2 > 3 > Program received signal SIGINT, Interrupt. 0x00007ffff6f81433 in select () from /lib/x86_64-linux-gnu/libc.so.6 (gdb)

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Marc, short sigsegv tracking Q. FFI failed malloc maybe - what's your thought?
by Adam 20 Jan '16

20 Jan '16

Marc, I got a sigsegv. I suspect it's because some FFI got a failed malloc() maybe, that the Scheme code then not handled as it should. Or it could be some FFI-related heap corruption (basically all Scheme code is safe so shouldn't cause any of that). Gambit in itself is 100% malloc-failure-safe right, so there is not one single instance when Gambit code actually would Also maybe it could be how I pass values between C and Scheme, that something is broken somewhere there - what did the introduction of the ___return() macro really resolve?? I just wanted to ask you to have a quick look at the GDB output below, to give your thought on what would be more and less plausible sources of this error. Finally, in an environment where you want to maximize reliability, would there be some way to add extra heap corruption checks?? As to be able to understand where the corruption actually happened - i mean what we get here is just a code pointer into the Gambit VM code, it's completely un-instructive. You know like that GCC patch that pads the stack with extra bytes and then checks, StackGuard or whatever it's called. I guess in the case of my crash here below, the actual problem is that someone overwrote the stack frame right? Thanks!! (gdb) thread apply all bt Thread 1 (process 16563): #0 0x00000c4a6fb10905 in ___H__20___kernel (_(short *)=0xc4a707222a0 <___gstate>) at _kernel.c:4358 Backtrace stopped: Cannot access memory at address 0x7f7ffffd1028 that line is: /* setup internal return continuation frame */ ra = ___ps->temp1; ___RETI_GET_CFS(ra,fs) <- this one! ___ADJFP(___ROUND_TO_MULT(fs,___FRAME_ALIGN)-fs) ___PUSH_REGS /* push all GVM registers (live or not) */ ___PUSH(ra) /* push return address */ and then additionally: (gdb) info locals descr = 13524638833968 fs = <optimized out> ra = 13524639556321 ___r4 = <optimized out> ___r1 = 0 ___hlbltbl = {0x0, 0x40fbe4, 0x40fcdf, 0x4172d2, 0x40fd2a, 0x41248a, 0x40fdcc, 0x40fe13, 0x40fe2e, 0x41eb0c, 0x40feb9, 0x40ff2a, 0x40ff73, 0x40ff9b, 0x40ffba, 0x40ffd9, 0x40fff8, 0x410017, 0x410036, 0x410055, 0x4101b3, 0x4105af, 0x4105db, 0x41066f, 0x410678, 0x4106ca, 0x41073e, 0x0, 0x41075a, 0x4107f1, 0x4108ef, 0x410adc, 0x410b7d, 0x410c85, 0x410d98, 0x410ec3, 0x41123c, 0x4116a0, 0x411cb1, 0x411d9e, 0x411e5c, 0x4120dc, 0x0, 0x41214e, 0x412211, 0x0, 0x412269, 0x0, 0x4122e0, 0x0, 0x412357, 0x0, 0x412425, 0x0, 0x4124b9, 0x0, 0x412542, 0x415d4e, 0x0, 0x4125f7, 0x0, 0x4126a2, 0x412716, 0x4127cd, 0x0, 0x412802, 0x4128bf, 0x0, 0x4128c4, 0x0, 0x41296f, 0x4129d7, 0x412a8e, 0x0, 0x412ac3, 0x412b80, 0x0, 0x412b85, 0x0, 0x412c30, 0x412d09, 0x0, 0x412d30, 0x412e09, 0x0, 0x412e30, 0x412f09, 0x0, 0x412f30, 0x413009, 0x0, 0x413030, 0x0, 0x4130a0, 0x0, 0x4130fc, 0x0, 0x413192, 0x41328a, 0x4132d3, 0x0, 0x41330c, 0x4133c9, 0x0, 0x4133ce, 0x0, 0x413479, 0x413552, 0x0, 0x413579, 0x413652, 0x0, 0x413679, 0x0, 0x4136d5, 0x4137bb, 0x413804, 0x0, 0x413839, 0x4138f6, 0x0, 0x4138fb, 0x0, 0x4139a6, 0x413a7f, 0x0, 0x413aa6, 0x413b7f, 0x0, 0x413ba6, 0x0, 0x413c02, 0x413ce8, 0x413d31, 0x0, 0x413d66, 0x413e23, 0x0, 0x413e28, 0x0, 0x413ed3, 0x413fac, 0x0, 0x413fd3, 0x4140ac, 0x0, 0x4140d3, 0x0, 0x41412f, 0x414215, 0x41425e, 0x0, 0x414293, 0x414350, 0x0, 0x414355, 0x0, 0x414400, 0x4144d9, 0x0, 0x414500, 0x4145d9, 0x0, 0x414600, 0x4146d9, 0x0, 0x414700, 0x4147d9, 0x0, 0x414800, 0x41490b, 0x414954, 0x0, 0x41498d, 0x414a4a, 0x0, 0x414a4f, 0x0, 0x414afa, 0x414bd3, 0x0, 0x414bfa, 0x414cd3, 0x0, 0x414cfa, 0x414dd3, 0x0, 0x414dfa, 0x414ed3, 0x0, 0x414efa, 0x414fe9, 0x415032, 0x0, 0x415067, 0x415124, 0x0, 0x415129, 0x0, 0x4151d4...} _(char *) = <optimized out> ___temp = <optimized out> ___hp = <error reading variable ___hp (Cannot access memory at address 0x7f7ffffcefa0)> _(float, *) = 0xc4d48ab94c0 _(long double, ) = <error reading variable _(long double, ) (Cannot access memory at address 0x7f7ffffcef68)> ___r2 = 13524703568041 ___start = <optimized out> ___r3 = <error reading variable ___r3 (Cannot access memory at address 0x7f7ffffcef60)> (gdb) info args _(short *) = 0xc4a707222a0 <___gstate>

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Soft Scheme?
by Raoul Duke 19 Jan '16

19 Jan '16

Has anybody tried Soft Scheme on Gambit? http://www.seas.upenn.edu/~sweirich/types/archive/1993/msg00169.html (P.s. I'd like to suggest that the mailing list move to a, well, better system than Mailman e.g. one that makes searching easy. :-)

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Patch for _univlib.scm to enable fast bignum arithmetic in javascript backend.
by Bradley Lucier 18 Jan '16

18 Jan '16

The limits on the size of bignums where ffts are used still need to be changed, but here is a patch for _univlib.scm that adds the primitives. Change _num.scm to have (macro-case-target ((C) (c-declare "#include \"mem.h\"") (##define-macro (use-fast-bignum-algorithms) #t)) (else (##define-macro (use-fast-bignum-algorithms) #t))) Add -never-return-jump to the makefile for _gambit.js. Apply this patch to _univlib.scm. Brad

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Scheme job opportunity
by Petersen, Chris 18 Jan '16

18 Jan '16

Hi fellow gambitters, Anyone interested in hacking Scheme for work and contributing to advanced medical research? The LambdaNative team in Vancouver is looking for a competent coder with broad engineering interests+abilities. You can apply via the UBC job board link below. Click “Advanced search” and enter Job Opening ID 22477. http://www.hr.ubc.ca/careers-postings/staff.php Cheers Chris

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[ANN] Gambit v4.8.3 released
by gambit＠iro.umontreal.ca 15 Jan '16

15 Jan '16

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Converting uint32 to scheme object
by Alex Silva 08 Jan '16

08 Jan '16

Hello list, I am currently writing some FFI code that interfaces with libtiff to read tags from TIFF image files. The values of these tags have different C types and using the right type is needed to avoid memory corruption. For reading tags with uint16 values the code is straightforward: ``` static ___SCMOBJ uint16_tag(TIFF *tiff, ttag_t tag) { uint16 val; int ret = TIFFGetField(tiff, tag, &val); return ret == 1 ? ___FIX(val) : ___FAL; } ``` But, since fixnums have less than 32 bits I cannot use the same code. It seems the solution would be something similar to: ``` static ___SCMOBJ uint32_tag(TIFF *tiff, ttag_t tag) { uint32 val; if(TIFFGetField(tiff, tag, &val) == 1) { ___SCMOBJ ret; ___U32_to_SCMOBJ(___ps, val, &ret, ___RETURN_POS); <---- ERROR return ret; } else { return ___FAL; } } ``` except that I don't know how to get hold of the processor state. Can anybody shed a light here? Thanks, -alex http://unendli.ch/

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Reader macro, read square brackets to vector and module system.
by caio rodrigues 07 Jan '16

07 Jan '16

Hi list. Is there any way to make Gambit repl read for instance [1 2 3 4 5] and turn it into a vector #(1 2 3 4 5) and also everything into brackets {x: 2 y: 4} into a hash table ? Another question: Is there any module system implementation for gambit that can import packages like Python, import sys or a clojure-like module system ? Example Clojure-like module system: *file: namespace.ss* --------------------------------- (ns namespace) (define (fun1 ....) (define (fun2 x y z) ...) --------------------------------- and then in the repl: (require 'namespace) (namespace/fun1 2 4 5) Thanks in advance.

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Parameter object allocation/get/set worstcase?
by Adam 04 Jan '16

04 Jan '16

Hi Marc, A long time ago you mentioned here that "parameter objects don't scale". I guess by that you meant that there are at least theoretically possible worstcase situations for their allocation, get or set operations or otherwise, that are far beyond say 1000 CPU cycles per object or operation. Would you mind explaning how bad the worstcase is, just to be able to understand what they're good for practically and what not? Thanks!

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Separate compilation targeting JavaScript
by Blake McBride 02 Jan '16

02 Jan '16

Any progress on separate compilation for a JavaScript target? (I am interested in using it for a large project that can't be done without separate compilation ability - 450+ screens). Thanks. Blake McBride

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