280 lines
14 KiB
Text
280 lines
14 KiB
Text
.\" List of all warnings; source of warn_msg and warn.h
|
|
.\"
|
|
.\" $Id$
|
|
.\"
|
|
.\" This file contains the warnings issued by the interpreter, together
|
|
.\" with their names and values in the code of the interpreter. Some of
|
|
.\" the source files of the interpreter are generated from the Wn
|
|
.\" macros in this file.
|
|
.\" When modifying this file, preserve the parameters of the Wn macros.
|
|
.de Wn \" <text> <define> <value>
|
|
.IP \\$3. 7
|
|
.B "\\$1"
|
|
.br
|
|
.. Wn
|
|
.bp
|
|
.DS C
|
|
APPENDIX A
|
|
.DE
|
|
.SH
|
|
List of Warnings.
|
|
.PP
|
|
The shadow-byte administration makes it possible to check for a
|
|
wide range of errors during run-time.
|
|
We have tried to make the diagnostics self-explanatory and especially useful
|
|
for the C-programmer.
|
|
The warnings are printed in the message file, together with source file
|
|
and line number.
|
|
The complete list of warnings is presented here, followed by an
|
|
explanation of what might be wrong.
|
|
Often, these explanations implicitly assume that the program
|
|
being interpreted, was originally written in C (and not Pascal, Basic etc.).
|
|
.LP
|
|
.I "Reading the load file"
|
|
.Wn "Floating point instructions flag in header ignored" WFLUSED 1
|
|
.Wn "No float initialisation in this version" WFLINIT 2
|
|
The interpreter was compiled with the NOFLOAT option; code involving
|
|
floating point operations can be run as long as the actual
|
|
instructions are avoided.
|
|
.Wn "Extra-test flag in header ignored" WEXTRIGN 4
|
|
The interpreter already tests anything conceivable.
|
|
.Wn "Maximum line number in header was 0" WNLINEZR 5
|
|
This number could be used to allocate tables for tallying; these tables are,
|
|
however, expanded as needed, so the number is immaterial.
|
|
.Wn "Bad float initialisation" WBADFLOAT 7
|
|
The loadfile contains a floating point denotation which does not
|
|
satisfy the syntax (see 2.6).
|
|
Examining the loadfile (with \fBod \-c\fP) might show the syntax error.
|
|
Probably there is a bug in the front-end, creating floats with
|
|
a bad syntax.
|
|
.LP
|
|
.I "System calls"
|
|
.Wn "IOCTL \- bad or unimplemented request" WBADIOCTL 11
|
|
The second parameter to the ioctl() request (the operation code) is invalid or
|
|
not implemented; since there are many different opcodes on the various UNIX
|
|
systems, it is difficult to tell which. The system call fails.
|
|
.Wn "MPXCALL \- not (yet) implemented" WMPXIMP 14
|
|
.Wn "PROFIL \- not (yet) implemented" WPROFILIMP 15
|
|
.Wn "PTRACE \- not (yet) implemented" WPTRACEIMP 16
|
|
The monitor calls \fImpxcall()\fP, \fIprofil()\fP and \fIptrace()\fP
|
|
have not been implemented. The monitor call fails.
|
|
.Wn "Inaccessible memory in system call" WMONFLT 21
|
|
Bad pointers passed to system calls do not cause a memory fault (which in UNIX
|
|
would happen to the kernel), but cause the system call to fail with the UNIX
|
|
variable errno set to 14 (EFAULT). It seems likely that the program is at
|
|
fault, but there is also a good possibility that a library routine made
|
|
unwarranted assumptions about word size and pointer size.
|
|
.Wn "READ \- buffer resides in unallocated memory" WRUMEM 23
|
|
.Wn "READ \- buffer across global data area and heap" WRGDAH 24
|
|
When the buffer passed to the read() system call is situated (completely
|
|
or partially) in unallocated memory (beyond \fIHP\fP) or begins
|
|
in the global data area and ends in the heap, the appropriate warning
|
|
is given.
|
|
The buffer is not written.
|
|
.Wn "WRITE \- buffer resides in unallocated memory" WWUMEM 25
|
|
.Wn "WRITE \- buffer across global data area and heap" WWGDAH 26
|
|
.Wn "WRITE \- (part of) global buffer is undefined" WWGUNDEF 27
|
|
.Wn "WRITE \- (part of) local buffer is undefined" WWLUNDEF 28
|
|
The first two are equivalent to the READ-errors above.
|
|
Writing out a buffer usually makes no sense when the contents are undefined,
|
|
so one of the latter two warnings will be generated in this case.
|
|
A global buffer resides in the data partition; a local buffer resides in
|
|
the stack partition.
|
|
This corresponds to global and local variables in a C-program.
|
|
In the first two cases the WRITE is not performed, in the latter two cases
|
|
it is.
|
|
.LP
|
|
.I "Traps and signals"
|
|
.Wn "SIGTRP \- bad signo argument" WILLSN 31
|
|
The \fIsigtrp()\fP monitor call allows \fIsig_no\fP arguments in the
|
|
range [1..17] (UNIX Version 7 signals); the actual argument is out of range.
|
|
.Wn "SIGTRP \- signo argument is a synchronous trap" WUNIXTR 32
|
|
The signal is one that can only be caused synchronously by the running program
|
|
on UNIX; it cannot occur to an interpreted program.
|
|
.Wn "SIGTRP \- bad trapno argument" WILLTN 33
|
|
The \fIsigtrp()\fP monitor call allows \fItrap_no\fP arguments between 0 and
|
|
252, and the special values \-2 and \-3; the actual argument is not one of
|
|
these.
|
|
.Wn "Heap overflow due to command line limitation" WEHEAP 36
|
|
.Wn "Stack overflow due to command line limitation" WESTACK 37
|
|
The maximum sizes of the heap and the stack can be limited by options on the
|
|
command line. If overflow occurs due to such limitations, the corresponding
|
|
trap is taken, preceded by one of the above warnings. If the memory of the
|
|
interpreter itself is exhausted, a fatal error follows.
|
|
.LP
|
|
.I "Run-time type checking"
|
|
.Wn "Local character expected" WLCEXP 41
|
|
.Wn "Global character expected" WGCEXP 42
|
|
.Wn "Local integer expected" WLIEXP 43
|
|
.Wn "Global integer expected" WGIEXP 44
|
|
.Wn "Local float expected" WLFEXP 45
|
|
.Wn "Global float expected" WGFEXP 46
|
|
.Wn "Local data pointer expected" WLDPEXP 47
|
|
.Wn "Global data pointer expected" WGDPEXP 48
|
|
.Wn "Local instruction pointer expected" WLIPEXP 49
|
|
.Wn "Global instruction pointer expected" WGIPEXP 50
|
|
In general, a type violation has taken place when one of
|
|
these warnings is given.
|
|
The \fBfloat\fP- and \fBinstruction pointer\fP warnings are rare and will
|
|
usually be easy traceable.
|
|
\fBInteger/character expected\fP will normally occur when unsigned arithmetic
|
|
is performed on datapointers or when memory containing objects other than
|
|
integers is copied bytewise.
|
|
Often, this warning is followed by a warning \fBdatapointer expected\fP.
|
|
This is due to our decision of transforming pointers to (unsigned) integers
|
|
after doing unsigned arithmetic on them.
|
|
When such a transformed integer is dereferenced (as if it were a pointer)
|
|
or, in general, when it is treated as a pointer, this results in a warning.
|
|
The present library implementation of malloc() causes such a
|
|
sequence of errors.
|
|
.LP
|
|
These messages are always followed by a tentative description of what is found
|
|
in memory at the offending place.
|
|
.Wn "Actual memory is undefined" WWASUND 61
|
|
.Wn "Actual memory contains an integer" WWASINT 62
|
|
.Wn "Actual memory contains a float" WWASFLOAT 63
|
|
.Wn "Actual memory contains a data pointer" WWASDATAP 64
|
|
.Wn "Actual memory contains an instruction pointer" WWASINSP 65
|
|
.Wn "Actual memory contains mixed information" WWASMISC 66
|
|
If the contents of the area was undefined,
|
|
check the source code for an uninitialized variable of the mentioned type.
|
|
Officially, the use of an undefined value
|
|
should result in a EIUND or EFUND trap but the occurrence is
|
|
so common that a warning is more appropriate.
|
|
The contents of memory are described as mixed if the data consists of pieces
|
|
of different types. This happens, e.g., when caller and callee do not agree on
|
|
the types and lengths of the parameters.
|
|
.LP
|
|
.I "Protection"
|
|
.br
|
|
.Wn "Destroying contents of ROM (at or near loc 0)" WDESROM 71
|
|
The program stores a value in Read-Only Memory; the only ROM in the present
|
|
implementation is the area near location 0. The warning probably results from
|
|
storing under a NULL pointer. This is only a warning, the store operation is
|
|
executed normally. Reads from location 0 are not detected.
|
|
.Wn "Destroying contents of Return Status Block" WDESRSB 72
|
|
The Return Status Block is the stack area containing the return address, the
|
|
dynamic link, etc.
|
|
This may or may not be an error.
|
|
The current implementation of \fIsetjmp()\fP/\fIlongjmp()\fP
|
|
may be responsible for it.
|
|
If the program does not use setjmp(), there \fIis\fP something
|
|
very wrong (e.g. argument for ASP too large).
|
|
Note that there are some library routines (such as \fIalarm()\fP) which
|
|
use \fIsetjmp()\fP.
|
|
.Wn "Logical operation using undefined operand(s)" WUNLOG 81
|
|
.Wn "Comparing undefined operand(s)" WUNCMP 82
|
|
The logical operations AND, XOR, IOR, COM and the compare operation
|
|
CMS do their jobs bytewise.
|
|
If one of the bytes is found to be undefined, the corresponding warning
|
|
is given, and the operation is stopped immediately.
|
|
The stack is adjusted so interpretation may continue.
|
|
.br
|
|
It is hard to say what went wrong.
|
|
Possibly, the argument of the instruction at hand (which indicates the
|
|
size of the objects to be compared), was too large.
|
|
.LP
|
|
.I "Bad operands"
|
|
.Wn "Shift over negative distance" WSHNEG 91
|
|
.Wn "Shift over too large distance" WSHLARGE 92
|
|
Shift instructions yield undefined results if the shift distance is negative
|
|
or larger than the object size.
|
|
.Wn "Pointer arithmetic yields pointer to bad segment" WSEGADP 93
|
|
When doing pointer arithmetic (ADP, ADS), the operand and result pointer
|
|
must be in the same \fIsegment\fP (see sec. 4).
|
|
E.g. loading the address of the first local and adding 20 to it will
|
|
certainly give this warning.
|
|
.Wn "Subtracting pointers to different segments" WSEGSBS 94
|
|
Pointers may be subtracted only if they point into the same segment.
|
|
.Wn "Pointer arithmetic with NULL pointer" WNULLPA 96
|
|
By definition it is illegal to do arithmetic with null pointers.
|
|
Integers with the size of a pointer and the value zero are recognized
|
|
as NULL pointers.
|
|
A well-known C-trick to compute the offset of some field in a struct
|
|
is converting the null-pointer to the type of the struct and simply
|
|
taking the address of the field.
|
|
This trick will \-when translated and interpreted\- generate this warning
|
|
because it results in arithmetic with the NULL pointer.
|
|
.LP
|
|
.I "Return area"
|
|
.Wn "Returned function result too large" WRFUNLAR 101
|
|
.Wn "Returned function result too small" WRFUNSML 102
|
|
This warning is generated when the size of the expected return value
|
|
is not equal to the size actually returned.
|
|
.br
|
|
An interpreted program may have fallen through the end of
|
|
the code without explicitly doing an \fIexit()\fP or \fIreturn()\fP.
|
|
The start-up routine (\fIcrt0()\fP) however always expects to get some
|
|
value returned by the program proper.
|
|
.br
|
|
Another (less probable) possibility of course is that the code contains
|
|
a subroutine or function call that does not return properly (e.g.
|
|
it returns a short instead of a long).
|
|
.Wn "Returned function result may be garbled" WRFUNGAR 103
|
|
This warning will be generated, when the contents of the FRA are fetched
|
|
after some instruction is executed which can mess up the area.
|
|
Compiler-generated loadfiles should not generate this message.
|
|
.LP
|
|
.I "Return Status Block"
|
|
.Wn "RET did not find a Return Status Block" WRETBAD 111
|
|
.Wn "Used RET to return from a trap" WRETTRAP 112
|
|
The RET instruction found a garbled Return Status Block, or on that resulted
|
|
from a trap.
|
|
.Wn "RTT did not find a Return Status Block" WRTTBAD 115
|
|
.Wn "RTT on empty stack" WRTTEMPTY 116
|
|
.Wn "Used RTT to return from a call" WRTTCALL 117
|
|
.Wn "Used RTT to return from a non-returnable trap" WRTTNRTT 118
|
|
The RTT (Return from Trap) instruction found a Return Status block that was not
|
|
created properly by a trap.
|
|
.Wn "Stack Pointer too large in RET" WRETSTL 121
|
|
.Wn "Stack Pointer too small in RET" WRETSTS 122
|
|
.Wn "Stack Pointer too large in RTT" WRTTSTL 125
|
|
.Wn "Stack Pointer too small in RTT" WRTTSTS 126
|
|
According to the EM Manual (4.2), "the value of SP just after the return
|
|
value has been popped must be the same as the
|
|
value of SP just before executing the first instruction of the
|
|
invocation."
|
|
If the Stack Pointer is too large, some dynamically allocated item or some
|
|
temporary result may have been left behind on the stack.
|
|
If the Stack Pointer is too small, some locals have been unstacked.
|
|
Since the interpreter has enough information in the Return Status Block, it
|
|
recovers correctly from these errors.
|
|
.LP
|
|
.I "Traps"
|
|
.LP
|
|
Some traps have ambiguous or non-obvious causes.
|
|
As far as possible, these are preceded by a warning, explaining the
|
|
circumstances of the trap.
|
|
.Wn "Trap ESTACK: DCH on bad LB" WDCHBADLB 131
|
|
.Wn "Trap ESTACK: LPB on bad LB" WLPBBADLB 132
|
|
.Wn "Trap ESTACK: SP retracted over Return Status Block" WSPGTLB 133
|
|
.Wn "Trap ESTACK: SP moved into data area" WSPINHEAP 134
|
|
.Wn "Trap ESTACK: SP set to non-word-boundary" WSPODD 135
|
|
.Wn "Trap ESTACK: LB set out of stack" WLBOUT 136
|
|
.Wn "Trap ESTACK: LB set to non-word-boundary" WLBODD 137
|
|
.Wn "Trap ESTACK: LB set to position where there is no RSB" WLBRSB 138
|
|
.Wn "Trap EHEAP: HP retracted into Global Data Area" WHPGDA 141
|
|
.Wn "Trap EHEAP: HP pushed into stack" WHPSTACK 142
|
|
.Wn "Trap EHEAP: HP set to non-word-boundary" WHPODD 143
|
|
.Wn "Trap EILLINS: unknown opcode" WBADOPC 151
|
|
.Wn "Trap EILLINS: conversion with unacceptable size for this machine" WILLCONV 152
|
|
.Wn "Trap EILLINS: FIL with non-existing address" WILLFIL 153
|
|
.Wn "Trap EILLINS: LFR with too large size" WILLLFR 154
|
|
.Wn "Trap EILLINS: RET with too large size" WILLRET 155
|
|
.Wn "Trap EILLINS: instruction argument of class c does not fit a word" WARGC 156
|
|
.Wn "Trap EILLINS: instruction on double word on machine with word size 4" WARGD 157
|
|
.Wn "Trap EILLINS: local offset too large" WARGL 158
|
|
.Wn "Trap EILLINS: instruction argument of class g not in GDA" WARGG 159
|
|
.Wn "Trap EILLINS: fragment offset too large" WARGF 160
|
|
.Wn "Trap EILLINS: counter in lexical instruction out of range" WARGN 161
|
|
.Wn "Trap EILLINS: non-existent procedure identifier" WARGP 162
|
|
.Wn "Trap EILLINS: illegal register number" WARGR 163
|
|
.Wn "Trap EBADPC: jump out of text segment" WPCOVFL 172
|
|
.Wn "Trap EBADPC: jump out of procedure fragment" WPCPROC 173
|
|
.Wn "Trap EBADGTO: GTO does not restore an existing RSB" WGTORSB 181
|
|
.Wn "Trap EBADGTO: GTO descriptor on the stack" WGTOSTACK 182
|
|
.Wn "Trap caused by TRP instruction" WTRP 191
|
|
.ig
|
|
.Wn "Last warning" WMSG 199
|
|
!Leave these lines here!
|
|
..
|