[PATCH] find-debuginfo: Allow overriding binutils tools

[Mark Wielaard]

find-debuginfo relies on a couple of binutils tools (readelf, objcopy
and nm) that might not have been build with cross-arch support. Make
it possible to configure with specific (target) versions and to
override the specific binaries by setting READELF, OBJCOPY or NM
environment variables.

    * Makefile.am (do_subst): Add OBJCOPY and NM substitutions.
    * configure.ac: Add OBJCOPY and NM tools override.
    * scripts/find-debuginfo.in: Allow READELF, OBJCOPY and NM
    environment overrides.

Signed-off-by: Mark Wielaard <mark@klomp.org>
---
 Makefile.am               |  2 ++
 configure.ac              |  2 ++
 scripts/find-debuginfo.in | 20 ++++++++++++++------
 3 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/Makefile.am b/Makefile.am
index 35fd947f8db2..562ffa46fa30 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -34,6 +34,8 @@ CLEANFILES = $(bin_SCRIPTS)
 do_subst = ($(SED) -e 's,[@]PACKAGE[@],$(PACKAGE),g' \
 		   -e 's,[@]VERSION[@],$(VERSION),g' \
 		   -e 's,[@]READELF[@],$(READELF),g' \
+		   -e 's,[@]OBJCOPY[@],$(OBJCOPY),g' \
+		   -e 's,[@]NM[@],$(NM),g' \
 		   -e 's,[@]DWZ_J[@],$(DWZ_J),g')
 
 find-debuginfo: $(top_srcdir)/scripts/find-debuginfo.in Makefile
diff --git a/configure.ac b/configure.ac
index 32dd27d287a3..ad4d70c63995 100644
--- a/configure.ac
+++ b/configure.ac
@@ -45,6 +45,8 @@ m4_version_prereq([2.70], [AC_PROG_CC], [AC_PROG_CC_C99])
 AC_PROG_LN_S
 AC_CHECK_TOOL([LD], [ld])
 AC_CHECK_TOOL([READELF], [readelf])
+AC_CHECK_TOOL([OBJCOPY], [objcopy])
+AC_CHECK_TOOL([NM], [nm])
 AM_MISSING_PROG(HELP2MAN, help2man)
 
 # Whether dwz support -j.
diff --git a/scripts/find-debuginfo.in b/scripts/find-debuginfo.in
index 7f2c00728b94..4cc49f2f8cd0 100755
--- a/scripts/find-debuginfo.in
+++ b/scripts/find-debuginfo.in
@@ -108,6 +108,14 @@ EOF
 install_dir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 PATH=${install_dir}:$PATH
 
+# A couple of binutils helper tools are used in this script.
+# Let the user override them by setting them in environment variables.
+# The default is the (target variant) of the tool found when debugedit
+# was configured.
+READELF=${READELF:=@READELF@}
+OBJCOPY=${OBJCOPY:=@OBJCOPY@}
+NM=${NM:=@NM@}
+
 # With -g arg, pass it to strip on libraries or executables.
 strip_g=false
 
@@ -360,7 +368,7 @@ add_minidebug()
   # symbol and NOBITS sections so cannot use --keep-only because that is
   # too aggressive. Field $2 is the section name, $3 is the section type
   # and $8 are the section flags.
-  local remove_sections=`@READELF@ -W -S "$debuginfo" \
+  local remove_sections=`${READELF} -W -S "$debuginfo" \
 	| awk '{ if (index($2,".debug_") != 1 \
 		     && ($3 == "PROGBITS" || $3 == "NOTE" || $3 == "NOBITS") \
 		     && index($8,"A") == 0) \
@@ -368,20 +376,20 @@ add_minidebug()
 
   # 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"
+  ${NM} -D "$binary" --format=posix --defined-only | awk '{ print $1 }' | sort > "$dynsyms"
   # Extract all the text (i.e. function) symbols from the debuginfo
   # Use format sysv to make sure we can match against the actual ELF FUNC
   # symbol type. The binutils nm posix format symbol type chars are
   # ambigous for architectures that might use function descriptors.
-  nm "$debuginfo" --format=sysv --defined-only | awk -F \| '{ if ($4 ~ "FUNC") print $1 }' | sort > "$funcsyms"
+  ${NM} "$debuginfo" --format=sysv --defined-only | awk -F \| '{ if ($4 ~ "FUNC") 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 $remove_sections --keep-symbols="$keep_symbols" "$debuginfo" "$mini_debuginfo" &> /dev/null
+  ${OBJCOPY} -S $remove_sections --keep-symbols="$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"
+  ${OBJCOPY} --add-section .gnu_debugdata="$mini_debuginfo" "$binary"
   rm -f "$dynsyms" "$funcsyms" "$keep_symbols" "$mini_debuginfo"
 }
 
@@ -516,7 +524,7 @@ do_file()
   if test "$f_writable" = "false"; then
     chmod u+w "$f"
   fi
-  objcopy --merge-notes "$f" 2>/dev/null || true
+  ${OBJCOPY} --merge-notes "$f" 2>/dev/null || true
   if test "$f_writable" = "false"; then
     chmod u-w "$f"
   fi
-- 
2.48.1