From e8cee3d3957786e8682ddf7077659575a2cf8052 Mon Sep 17 00:00:00 2001
From: Thierry Vignaud <tv@mageia.org>
Date: Fri, 27 Jul 2012 17:38:50 +0000
Subject: add support for mini debug packages (disabled by default)

(https://fedoraproject.org/wiki/Features/MiniDebugInfo)
---
 Makefile.am       |  3 ++-
 NEWS              |  2 ++
 UPSTREAM          |  1 +
 build.macros.in   |  7 ++++++-
 dwz.macros.in     | 39 +++++++++++++++++++++++++++++++++++++++
 find-debuginfo.sh | 37 ++++++++++++++++++++++++++++++++++++-
 6 files changed, 86 insertions(+), 3 deletions(-)
 create mode 100644 dwz.macros.in

diff --git a/Makefile.am b/Makefile.am
index c83f107..eba404a 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -10,7 +10,8 @@ pkg_gdata = \
 		   rpmrc
 
 pkg_sysconf_macros_tmp = \
-		   build.macros
+		   build.macros \
+		   dwz.macros
 
 pkg_data_in = $(pkg_gdata:=.in)
 
diff --git a/NEWS b/NEWS
index cb04589..ede6095 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,5 @@
+- add support for mini debug packages
+  (https://fedoraproject.org/wiki/Features/MiniDebugInfo)
 - document Mageia divergences with upstream
 - fix typo that breaks emiting maven provides
 - generate a perlapi-<version> provide when libperl.so is found
diff --git a/UPSTREAM b/UPSTREAM
index b6e7b79..8ea13a9 100644
--- a/UPSTREAM
+++ b/UPSTREAM
@@ -11,6 +11,7 @@ Those that could be replaced by patches:
   + allow for for only stripping files without creating debug package contents
     by setting DISABLE_DEBUG environment variable
   + check real debug directory
+  ~ minidebug (merged soon)
 
 Other divergences:
 
diff --git a/build.macros.in b/build.macros.in
index d90e846..aad0ffe 100644
--- a/build.macros.in
+++ b/build.macros.in
@@ -155,6 +155,11 @@ GCONF_CONFIG_SOURCE=`%{_gconftool_bin} --get-default-source` %{_gconftool_bin} -
 %__distro_section %{?distro_section:%distro_section}%{?!distro_section:core}
 %mkrel(c:) %{-c: 0.%{-c*}.}%{1}%{?subrel:.%subrel}%{?distsuffix:%distsuffix}%{?!distsuffix:.mga}%{?distro_release:%distro_release}%([ "%{__distro_section}" != "core" ] && echo .%__distro_section)
 
+# Include minimal debug information in build binaries.
+# Requires _enable_debug_packages.
+#
+#%_include_minidebuginfo       0
+
 #------------------------------------------------------------------------------
 # definions merged from manbo-setup-build
 #
@@ -303,7 +308,7 @@ export CFLAGS="%optflags"; export CXXFLAGS="%optflags"; export RPM_OPT_FLAGS="%o
 %{nil}
 
 %__debug_install_post   \
-   @RPMVENDORDIR@/find-debuginfo.sh "%{_builddir}/%{?buildsubdir}"\
+   @RPMVENDORDIR@/find-debuginfo.sh %{?_include_minidebuginfo:-m} "%{_builddir}/%{?buildsubdir}"\
 %{nil}
 
 
diff --git a/dwz.macros.in b/dwz.macros.in
new file mode 100644
index 0000000..f1e4813
--- /dev/null
+++ b/dwz.macros.in
@@ -0,0 +1,39 @@
+# Macros for reducing debug info size using dwz(1) utility.
+
+# The two default values below should result in dwz taking at most
+# 3GB of RAM or so on 64-bit hosts and 2.5GB on 32-bit hosts
+# on the largest *.debug files  (in mid 2012 those are
+# libreoffice-debuginfo, debuginfos containing
+# libxul.so.debug and libwebkitgtk-*.so.*.debug).
+# This needs to be tuned based on the amount of available RAM
+# on build boxes for each architecture as well as virtual address
+# space limitations if dwz is 32-bit program.  While it needs less
+# memory than 64-bit program because pointers are smaller, it can
+# never have more than 4GB-epsilon of RAM and on some architecture
+# even less than that (e.g. 2GB).
+
+# Number of debugging information entries (DIEs) above which
+# dwz will stop considering file for multifile optimizations
+# and enter a low memory mode, in which it will optimize
+# in about half the memory needed otherwise.
+%_dwz_low_mem_die_limit		 10000000
+# Number of DIEs above which dwz will stop processing
+# a file altogether.
+%_dwz_max_die_limit     	 50000000
+
+# On x86_64 increase the higher limit to make libwebkit* optimizable.
+# libwebkit* in mid 2012 contains roughly 87mil DIEs, and 64-bit
+# dwz is able to optimize it from ~1.1GB to ~410MB using 5.2GB of RAM.
+%_dwz_max_die_limit_x86_64	110000000
+
+# On ARM, build boxes often have only 512MB of RAM and are very slow.
+# Lower both the limits.
+%_dwz_low_mem_die_limit_armv5tel  4000000
+%_dwz_low_mem_die_limit_armv7hl	  4000000
+%_dwz_max_die_limit_armv5tel	 10000000
+%_dwz_max_die_limit_armv7hl	 10000000
+
+%_dwz_limit() %{expand:%%{?%{1}_%{_arch}}%%{!?%{1}_%{_arch}:%%%{1}}}
+%_find_debuginfo_dwz_opts --run-dwz\\\
+   --dwz-low-mem-die-limit %{_dwz_limit _dwz_low_mem_die_limit}\\\
+   --dwz-max-die-limit %{_dwz_limit _dwz_max_die_limit}
diff --git a/find-debuginfo.sh b/find-debuginfo.sh
index 3427fdb..c2bc7df 100755
--- a/find-debuginfo.sh
+++ b/find-debuginfo.sh
@@ -2,7 +2,7 @@
 #find-debuginfo.sh - automagically generate debug info and file list
 #for inclusion in an rpm spec file.
 #
-# Usage: find-debuginfo.sh [--strict-build-id] [-g] [-r]
+# Usage: find-debuginfo.sh [--strict-build-id] [-g] [-r] [-m]
 #	 		   [-o debugfiles.list]
 #			   [[-l filelist]... [-p 'pattern'] -o debuginfo.list]
 #			   [builddir]
@@ -29,6 +29,9 @@ strip_g=false
 # with -r arg, pass --reloc-debug-sections to eu-strip.
 strip_r=false
 
+# with -m arg, add minimal debuginfo to binary.
+include_minidebug=false
+
 # Barf on missing build IDs.
 strict=false
 
@@ -43,6 +46,9 @@ while [ $# -gt 0 ]; do
   -g)
     strip_g=true
     ;;
+  -m)
+    include_minidebug=true
+    ;;
   -o)
     if [ -z "${lists[$nout]}" -a -z "${ptns[$nout]}" ]; then
       out=$2
@@ -106,6 +112,32 @@ strip_to_debug()
   [ -n "$DISABLE_DEBUG" ] || chmod 444 "$1" || exit
 }
 
+add_minidebug()
+{
+  local debuginfo="$1"
+  local binary="$2"
+
+  local dynsyms=`mktemp`
+  local funcsyms=`mktemp`
+  local keep_symbols=`mktemp`
+  local mini_debuginfo=`mktemp`
+
+  # Extract the dynamic symbols from the main binary, there is no need to also have these
+  # in the normal symbol table
+  nm -D "$binary" --format=posix --defined-only | awk '{ print $1 }' | sort > "$dynsyms"
+  # Extract all the text (i.e. function) symbols from the debuginfo 
+  nm "$debuginfo" --format=posix --defined-only | awk '{ if ($2 == "T" || $2 == "t") print $1 }' | sort > "$funcsyms"
+  # Keep all the function symbols not already in the dynamic symbol table
+  comm -13 "$dynsyms" "$funcsyms" > "$keep_symbols"
+  # Copy the full debuginfo, keeping only a minumal set of symbols and removing some unnecessary sections
+  objcopy -S --remove-section .gdb_index --remove-section .comment --keep-symbols="$keep_symbols" "$debuginfo" "$mini_debuginfo" &> /dev/null
+  #Inject the compressed data into the .gnu_debugdata section of the original binary
+  xz "$mini_debuginfo"
+  mini_debuginfo="${mini_debuginfo}.xz"
+  objcopy --add-section .gnu_debugdata="$mini_debuginfo" "$binary"
+  rm -f "$dynsyms" "$funcsyms" "$keep_symbols" "$mini_debuginfo"
+}
+
 # Make a relative symlink to $1 called $3$2
 shopt -s extglob
 link_relative()
@@ -272,6 +304,9 @@ while read nlinks inum f; do
     chmod u-w "$f"
   fi
 
+  $include_minidebug && add_minidebug "${debugfn}" "$f"
+
+  
   if [ -n "$id" ]; then
     make_id_link "$id" "$dn/$(basename $f)"
     make_id_link "$id" "/usr/lib/debug$dn/$bn" .debug
-- 
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