Bug 1596656 - Move OBJCOPY to python configure. r=firefox-build-system-reviewers,andi

As a bonus, we also check and prefer llvm-objcopy when it's suitable.

Differential Revision: https://phabricator.services.mozilla.com/D136975

build/autoconf/toolchain.m4

@@ -85,7 +85,6 @@ AC_CHECK_PROGS(LIPO, "${TOOLCHAIN_PREFIX}lipo", :)
 AC_CHECK_PROGS(STRIP, "${TOOLCHAIN_PREFIX}strip", :)
 AC_CHECK_PROGS(OTOOL, "${TOOLCHAIN_PREFIX}otool", :)
 AC_CHECK_PROGS(INSTALL_NAME_TOOL, "${TOOLCHAIN_PREFIX}install_name_tool", :)
-AC_CHECK_PROGS(OBJCOPY, "${TOOLCHAIN_PREFIX}objcopy", :)
 PATH=$_SAVE_PATH
 ])
 

moz.configure

@@ -827,12 +827,38 @@ def readelf_when(compile_env, target, host):
 check_prog(
     "READELF",
     readelf,
-    what="readelf",
     when=readelf_when,
     paths=clang_search_path,
     validate=validate_readelf,
 )
 
+
+@depends(llvm_tool("llvm-objcopy"), toolchain_prefix)
+def objcopy(llvm_objcopy, toolchain_prefix):
+    commands = [llvm_objcopy[0], "objcopy"]
+    for prefix in toolchain_prefix or ():
+        commands.insert(1, "%sreadelf" % prefix)
+    return tuple(commands)
+
+
+def validate_objcopy(path):
+    if "llvm-objcopy" not in path:
+        return True
+    # llvm-objcopy doesn't support --only-keep-debug before llvm 9.0.
+    retcode, stdout, stderr = get_cmd_output(path, "--help")
+    return retcode == 0 and any(
+        l.startswith("  --only-keep-debug ") for l in stdout.splitlines()
+    )
+
+
+check_prog(
+    "OBJCOPY",
+    objcopy,
+    when=readelf_when,
+    paths=clang_search_path,
+    validate=validate_objcopy,
+)
+
 option("--enable-dtrace", help="Build with dtrace support")
 
 dtrace = check_header(

old-configure.in

@@ -63,16 +63,6 @@ if test "$COMPILE_ENVIRONMENT"; then
     MOZ_ANDROID_NDK
 fi # COMPILE_ENVIRONMENT
 
-case "$target" in
-*-android*|*-linuxandroid*)
-    ;;
-*-linux*)
-    AC_PATH_PROG(OBJCOPY,objcopy)
-    ;;
-esac
-
-AC_SUBST(OBJCOPY)
-
 dnl ========================================================
 dnl Checks for compilers.
 dnl ========================================================