7e5c1057bb
magic to converts scripts, since that is now handled
by genscripts.sh and the *.sc-sh scipt generators.
* config.h: Remove a bunch of macros defining emulations
and targets. This becomes one less file to edit when
adding emulations or targets.
* ldemul.h (struct ld_emulation_xfer_struct): Add
emulation_name and target_name fields.
* ldemul.c, ldemul.h: Define some default functions used
by most emulations (and remove from the *.em scripts).
* ldemul.c (ldemul_choose_target): Search the new
ld_emulations array using a loop (instead of a hardwired
nested if statement).
Define the ld_emulation from the automatically-geenrated
ldemul-list.h. This means you no longer have to edit ldemul.c
to add a new emulation.
* ldmain.c: Replace {GLD,LNK}960_EMULATION_NAME by
their expansions, since the former no longer exist.
* PORTING: A very rough first draft of a porting guide.
64 lines
2.4 KiB
Plaintext
64 lines
2.4 KiB
Plaintext
Some incomplete notes about porting GNU ld
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-----------------------------------------
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Before porting ld itself, you will need to port the BFD library.
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We tarlk about the 'host' system as the machine and software
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nevironment where ld runs (generates an execuitble *on*),
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while the 'target' is the machine ld generates an executable *for*.
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Most often, host==target, but ld supports cross-linking
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(and to some extent the same ld binary can be used a linker
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for multiple target rachitectures).
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Doing a 'host' port means working around broken or missing
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include files or libraries. ...
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Porting to a new target
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-----------------------
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Writing a new script script
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---------------------------
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You may need to write a new script file for your emulation.
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The variable RELOCATING is only set if relocation is happening
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(i.e. unless the linker is invoked with -r).
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Thus your script should has an action ACTION
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that should only be done when relocating,
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express that as:
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${RELOCATING+ ACTION}
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In general, this is the case for most assignments, which should look like:
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${RELOCATING+ _end = .}
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Also, you should assign absolute addresses to sections only
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when relocating, so:
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.text ${RELOCATING+ ${TEXT_START_ADDR}}:
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The forms:
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.section { ... } > section
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should be:
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.section { ... } > ${RELOCATING+ section}
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Old Makefile comments (re-write - FXIME!)
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-----------------------------------------
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# The .xn script is used if the -n flag is given (write-protect text)..
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# Sunos starts the text segment for demand-paged binaries at 0x2020
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# and other binaries at 0x2000, since the exec header is paged in
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# with the text. Some other Unix variants do the same.
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# For -n and -N flags the offset of the exec header must be removed.
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# This sed script does this if the master script contains
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# a line of the form ".text 0xAAAA BLOCK(0xBBBB):" - the
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# output will contain ".text 0xBBBB:". (For Sunos AAAA=2020 and BBBB=2000.)
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.x.xn:
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sed -e '/text/s/\.text .* BLOCK(\([^)]*\)):/.text \1:/' < $< >$*.xn
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# The .xN script is used if the -N flag is given (don't write-protect text).
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# This is like -n, except that the data segment need not be page-aligned.
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# So get rid of commands for page-alignment: We assume these use ALIGN
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# with a hex constant that end with 00, since any normal page size is be
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# at least divisible by 256. We use the 00 to avoid matching
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# anything that tries to align of (say) 8-byte boundaries.
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.xn.xN:
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sed -e '/ALIGN/s/ALIGN( *0x[0-9a-fA-F]*00 *)/./' < $< >$*.xN
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