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* ld.texinfo (Simple Example): Rewrite a few things as suggested

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by Nick Clifton <nickc@cygnus.com>.
	(PROVIDE): Likewise.
This commit is contained in:
Ian Lance Taylor 1998-04-22 03:55:41 +00:00
parent e3147bf286
commit 36a8f215e7
2 changed files with 39 additions and 16 deletions
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6
ld/ChangeLog
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@ -1,3 +1,9 @@
Tue Apr 21 23:07:07 1998 Ian Lance Taylor <ian@cygnus.com>
* ld.texinfo (Simple Example): Rewrite a few things as suggested
by Nick Clifton <nickc@cygnus.com>.
(PROVIDE): Likewise.
Tue Apr 21 09:55:06 1998 Nick Clifton <nickc@cygnus.com>
* emultempl/pe.em: Rename external arm interworking functions

49
ld/ld.texinfo
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@ -1338,7 +1338,7 @@ of debugging information.
Every loadable or allocatable output section has two addresses. The
first is the @dfn{VMA}, or virtual memory address. This is the address
the sectin will have when the output file is run. The second is the
the section will have when the output file is run. The second is the
@dfn{LMA}, or load memory address. This is the address at which the
section will be loaded. In most cases the two addresses will be the
same. An example of when they might be different is when a data section
@ -1423,6 +1423,14 @@ output section in some other way (other ways are described later), the
address is set from the current value of the location counter. The
location counter is then incremented by the size of the output section.
The first line inside the @samp{SECTIONS} command of the above example
sets the value of the special symbol @samp{.}, which is the location
counter. If you do not specify the address of an output section in some
other way (other ways are described later), the address is set from the
current value of the location counter. The location counter is then
incremented by the size of the output section. At the start of the
@samp{SECTIONS} command, the location counter has the value @samp{0}.
The second line defines an output section, @samp{.text}. The colon is
required syntax which may be ignored for now. Within the curly braces
after the output section name, you list the names of the input sections
@ -1435,12 +1443,19 @@ Since the location counter is @samp{0x10000} when the output section
@samp{.text} section in the output file to be @samp{0x10000}.
The remaining lines define the @samp{.data} and @samp{.bss} sections in
the output file. The @samp{.data} output section will be at address
@samp{0x8000000}. When the @samp{.bss} output section is defined, the
value of the location counter will be @samp{0x8000000} plus the size of
the @samp{.data} output section. The effect is that the @samp{.bss}
output section will follow immediately after the @samp{.data} output
section in memory.
the output file. The linker will place the @samp{.data} output section
at address @samp{0x8000000}. After the linker places the @samp{.data}
output section, the value of the location counter will be
@samp{0x8000000} plus the size of the @samp{.data} output section. The
effect is that the linker will place the @samp{.bss} output section
immediately after the @samp{.data} output section in memory
The linker will ensure that each output section has the required
alignment, by increasing the location counter if necessary. In this
example, the specified addresses for the @samp{.text} and @samp{.data}
sections will probably satisfy any alignment constraints, but the linker
may have to create a small gap between the @samp{.data} and @samp{.bss}
sections.
That's it! That's a simple and complete linker script.
@ -1760,11 +1775,12 @@ SECTIONS
@}
@end smallexample
In this example, if the program defines @samp{_etext}, the linker will
give a multiple definition error. If, on the other hand, the program
defines @samp{etext}, the linker will silently use the definition in the
program. If the program references @samp{etext} but does not define it,
the linker will use the definition in the linker script.
In this example, if the program defines @samp{_etext} (with a leading
underscore), the linker will give a multiple definition error. If, on
the other hand, the program defines @samp{etext} (with no leading
underscore), the linker will silently use the definition in the program.
If the program references @samp{etext} but does not define it, the
linker will use the definition in the linker script.
@node SECTIONS
@section SECTIONS command
@ -2439,8 +2455,8 @@ You can assign a section to a previously defined program segment by
using @samp{:@var{phdr}}. @xref{PHDRS}. If a section is assigned to
one or more segments, then all subsequent allocated sections will be
assigned to those segments as well, unless they use an explicitly
@code{:@var{phdr}} modifier. To prevent a section from being assigned
to a segment when it would normally default to one, use @code{:NONE}.
@code{:@var{phdr}} modifier. You can use @code{:NONE} to tell the
linker to not put the section in any segment at all.
Here is a simple example:
@smallexample
@ -2764,8 +2780,9 @@ If you place a section in one or more segments using @samp{:@var{phdr}},
then the linker will place all subsequent allocatable sections which do
not specify @samp{:@var{phdr}} in the same segments. This is for
convenience, since generally a whole set of contiguous sections will be
placed in a single segment. To prevent a section from being assigned to
a segment when it would normally default to one, use @code{:NONE}.
placed in a single segment. You can use @code{:NONE} to override the
default segment and tell the linker to not put the section in any
segment at all.
@kindex FILEHDR
@kindex PHDRS