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Correct bug in the object file output code leading to stack corruption
It turns out leaving a pointer to a stack allocated temporary in a
persistent data structure is not conducive to correct program operation.
Undo the export check setup in the object file output sequence so a
pointer to stack allocated memory is not left hanging when the function
returns. This seems to correct at least one mysterious crash bug, and
possibly others.
Thanks to Boisy Pitre for reporting the crash bug that led to this
discovery, as well as a previous crash bug that likely has the same
root cause.
Additional thanks to Ciaran Anscomb whose debugger wielding wizardry
revealed the exact location of this particular bit of unbrilliance.
author | William Astle <lost@l-w.ca> |
---|---|
date | Sat, 03 Aug 2024 14:30:06 -0600 |
parents | fc072f6cde09 |
children |
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >LWLINK</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REL="HOME" TITLE="LW Tool Chain" HREF="index.html"><LINK REL="PREVIOUS" TITLE="Cycle Counts" HREF="x832.html"><LINK REL="NEXT" TITLE="Linker Operation" HREF="x938.html"></HEAD ><BODY CLASS="CHAPTER" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >LW Tool Chain</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="x832.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="x938.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="CHAPTER" ><H1 ><A NAME="AEN838" ></A >Chapter 4. LWLINK</H1 ><P >The LWTOOLS linker is called LWLINK. This chapter documents the various features of the linker.</P ><DIV CLASS="SECTION" ><H1 CLASS="SECTION" ><A NAME="AEN841" >4.1. Command Line Options</A ></H1 ><P >The binary for LWLINK is called "lwlink". Note that the binary is in lower case. lwlink takes the following command line arguments.</P ><P ></P ><DIV CLASS="VARIABLELIST" ><DL ><DT ><CODE CLASS="OPTION" >--decb</CODE >, <CODE CLASS="OPTION" >-b</CODE ></DT ><DD ><P >Selects the DECB output format target. This is equivalent to <CODE CLASS="OPTION" >--format=decb</CODE ></P ></DD ><DT ><CODE CLASS="OPTION" >--output=FILE</CODE >, <CODE CLASS="OPTION" >-o FILE</CODE ></DT ><DD ><P >This option specifies the name of the output file. If not specified, the default is <CODE CLASS="OPTION" >a.out</CODE >.</P ></DD ><DT ><CODE CLASS="OPTION" >--format=TYPE</CODE >, <CODE CLASS="OPTION" >-f TYPE</CODE ></DT ><DD ><P >This option specifies the output format. Valid values are <CODE CLASS="OPTION" >decb</CODE > and <CODE CLASS="OPTION" >raw</CODE ></P ></DD ><DT ><CODE CLASS="OPTION" >--raw</CODE >, <CODE CLASS="OPTION" >-r</CODE ></DT ><DD ><P >This option specifies the raw output format. It is equivalent to <CODE CLASS="OPTION" >--format=raw</CODE > and <CODE CLASS="OPTION" >-f raw</CODE ></P ></DD ><DT ><CODE CLASS="OPTION" >--script=FILE</CODE >, <CODE CLASS="OPTION" >-s</CODE ></DT ><DD ><P >This option allows specifying a linking script to override the linker's built in defaults.</P ></DD ><DT ><CODE CLASS="OPTION" >--section-base=SECT=BASE</CODE ></DT ><DD ><P >Cause section SECT to load at base address BASE. This will be prepended to the built-in link script. It is ignored if a link script is provided.</P ></DD ><DT ><CODE CLASS="OPTION" >--map=FILE</CODE >, <CODE CLASS="OPTION" >-m FILE</CODE ></DT ><DD ><P >This will output a description of the link result to FILE.</P ></DD ><DT ><CODE CLASS="OPTION" >--library=LIBSPEC</CODE >, <CODE CLASS="OPTION" >-l LIBSPEC</CODE ></DT ><DD ><P >Load a library using the library search path. If LIBSPEC is prefixed with a colon (":"), then LIBSPEC is the precise filename to be searched for in the library path. Otherwise, LIBSPEC will have "lib" prepended and ".a" appended.</P ></DD ><DT ><CODE CLASS="OPTION" >--library-path=DIR</CODE >, <CODE CLASS="OPTION" >-L DIR</CODE ></DT ><DD ><P >Add DIR to the library search path.</P ></DD ><DT ><CODE CLASS="OPTION" >--debug</CODE >, <CODE CLASS="OPTION" >-d</CODE ></DT ><DD ><P >This option increases the debugging level. It is only useful for LWTOOLS developers.</P ></DD ><DT ><CODE CLASS="OPTION" >--help</CODE >, <CODE CLASS="OPTION" >-?</CODE ></DT ><DD ><P >This provides a listing of command line options and a brief description of each.</P ></DD ><DT ><CODE CLASS="OPTION" >--usage</CODE ></DT ><DD ><P >This will display a usage summary of each command line option.</P ></DD ><DT ><CODE CLASS="OPTION" >--version</CODE >, <CODE CLASS="OPTION" >-V</CODE ></DT ><DD ><P >This will display the version of LWLINK.</P ></DD ></DL ></DIV ></DIV ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="x832.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="x938.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Cycle Counts</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" > </TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Linker Operation</TD ></TR ></TABLE ></DIV ></BODY ></HTML >