common: Add symbol handling for generic lists into Makefile

This patch adds essential components for generation of the contents of
the linker section that is used by the linker-generated array. All of
the contents is held in a separate file, u-boot.lst, which is generated
at runtime just before U-Boot is linked.

The purpose of this code is to especially generate the appropriate
boundary symbols around each subsection in the section carrying the
linker-generated arrays. Obviously, the interim linker code for actual
placement of the variables into the section is generated too. The
generated file, u-boot.lst, is included into u-boot.lds via the linker
INCLUDE directive in u-boot.lds .

Adjustments are made in the Makefile and spl/Makefile so that the
u-boot.lds and u-boot-spl.lds depend on their respective .lst files.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Joe Hershberger <joe.hershberger@gmail.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Acked-by: Joe Hershberger <joe.hershberger@ni.com>
Tested-by: Joe Hershberger <joe.hershberger@ni.com>

1 files changed, 64 insertions, 0 deletions

diff --git a/helper.mk b/helper.mk
new file mode 100644
index 0000000000..79a1da01e3
--- /dev/null
+++ b/helper.mk
@@ -0,0 +1,64 @@
+#
+# Copyright (C) 2012 Marek Vasut <marex@denx.de>
+#
+# See file CREDITS for list of people who contributed to this
+# project.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation; either version 2 of
+# the License, or (at your option) any later version.
+#
+#########################################################################
+
+##
+# make_u_boot_list - Generate contents of u_boot_list section
+# 1:		The name of the resulting file (usually u-boot.lst)
+# 2:		Files to analyze for possible u_boot_list entries
+#
+# This function generates the contents of the u_boot_list section,
+# including all the border symbols for it's subsections. The operation
+# of this function is as follows, numbering goes per lines:
+#
+# 1) Dump the ELF header sections from all files supplied via $(2)
+# 2) Filter out all other stuff that does not belong into .u_boot_list
+#    section.
+# 3) Fix up the lines so that the resulting output is is in format
+#    ".u_boot_list.*".
+# 4) Remove the last .something$, since that only contains the name
+#    of the variable to be put into a subsection. This name is irelevant
+#    for generation of border symbols, thus of no interest, remove it.
+# 5) Take each line and for every dot "." in that line, print the whole
+#    line until that dot "." . This is important so that we have all
+#    parent border symbols generated as well.
+# 6) Load every line and firstly append "\a" at the end and print the
+#    line. Next, append "@" at the end and print the line. Finally,
+#    append "~" at the end of line. This will make sense in conjunction
+#    with 6) and 7).
+# 7) Sort the lines. It is imperative to use LC_COLLATE=C here because
+#    with this, the "\a" symbol is first and "~" symbol is last. Any
+#    other symbols fall inbetween. Symbols like "@", which marks the
+#    end of current line (representing current section) and ".", which
+#    means the line continues and thus represents subsection.
+# 8) With such ordering, all lines ending with "\a" will float at the
+#    begining of all lines with the same prefix. Thus it is easy to
+#    replace "\a" with __start and make it the __start border symbol.
+#    Very similarly for "~", which will be always at the bottom and so
+#    can be replaced by "__end" and made into the __end border symbol.
+#    Finally, every line ending with "@" symbol will be transformed
+#    into " *(SORT(${line}*)); " format, which in the linker parlance
+#    will allow it to trap all symbols relevant to the subsection.
+#
+define make_u_boot_list
+$(1): $(2)
+	$(OBJDUMP) -h $(2) | \
+	sed -n -e '/.*\.u_boot_list[^ ]\+/ ! {d;n}' \
+		-e 's/.*\(\.u_boot_list[^ ]\+\).*$$$$/\1/' \
+		-e 's/\.[^\.]\+$$$$//' \
+		-e ':s /^.\+$$$$/ { p;s/^\(.*\)\.[^\.]*$$$$/\1/;b s }' | \
+	sed -n -e 'h;s/$$$$/\a/p;g;s/$$$$/@/p;g;s/$$$$/~/p;' | \
+	LC_COLLATE=C sort -u | \
+	sed -n -e '/\a$$$$/ { s/\./_/g;s/\a$$$$/__start = .;/p; }'\
+		-e '/~$$$$/ { s/\./_/g;s/~$$$$/__end = .;/p; }'\
+		-e '/@$$$$/ { s/\(.*\)@$$$$/*(SORT(\1.*));/p }' > $(1)
+endef