diff mbox

[U-Boot] README.commands: Document what UNDEF_SYM does

Message ID 1348011772-8533-1-git-send-email-trini@ti.com
State Superseded
Delegated to: Tom Rini
Headers show

Commit Message

Tom Rini Sept. 18, 2012, 11:42 p.m. UTC
Signed-off-by: Tom Rini <trini@ti.com>
---
 doc/README.commands |    6 ++++++
 1 file changed, 6 insertions(+)

Comments

Jeroen Hofstee Sept. 19, 2012, 9:09 p.m. UTC | #1
On 09/19/2012 01:42 AM, Tom Rini wrote:
> +To ensure that the linker does not discard these symbols when linking
> +full U-Boot we use generate a list of all of the commands and force the
> +linker to first enter the symbol as undefined in the object so that
> +there is then a need for the symbol to be kept (UNDEF_SYM in the
> +Makefile).
> +
I have no idea what this is about, but my mind has difficulty parsing
this sentence.

"To ensure that the linker does not discard these symbols when linking
full U-Boot we use generate a list"

a generated list?

Regards,
Jeroen
Tom Rini Sept. 19, 2012, 9:17 p.m. UTC | #2
On Wed, Sep 19, 2012 at 11:09:56PM +0200, Jeroen Hofstee wrote:
> On 09/19/2012 01:42 AM, Tom Rini wrote:
> >+To ensure that the linker does not discard these symbols when linking
> >+full U-Boot we use generate a list of all of the commands and force the
> >+linker to first enter the symbol as undefined in the object so that
> >+there is then a need for the symbol to be kept (UNDEF_SYM in the
> >+Makefile).
> >+
> I have no idea what this is about, but my mind has difficulty parsing
> this sentence.
> 
> "To ensure that the linker does not discard these symbols when linking
> full U-Boot we use generate a list"
> 
> a generated list?

Bah, re-wrote the sentance a few times in my head as I was writing it.
... full U-Boot we geneate a list of all the commands we have built
(based on the sections mentioned above) and use that to force the linker
...
diff mbox

Patch

diff --git a/doc/README.commands b/doc/README.commands
index 27815d2..21abfb6 100644
--- a/doc/README.commands
+++ b/doc/README.commands
@@ -22,6 +22,12 @@  This makes it possible for the final link to extract all commands
 compiled into any object code and construct a static array so the
 command can be found in an array starting at __u_boot_cmd_start.
 
+To ensure that the linker does not discard these symbols when linking
+full U-Boot we use generate a list of all of the commands and force the
+linker to first enter the symbol as undefined in the object so that
+there is then a need for the symbol to be kept (UNDEF_SYM in the
+Makefile).
+
 If a new board is defined do not forget to define the command section
 by writing in u-boot.lds ($(TOPDIR)/board/boardname/u-boot.lds) these
 3 lines: