Re: PLT refs dependent upon gcc version...

[Roland McGrath <roland at hack dot frob dot com>]

I've committed the following.  Each arch maintainer with a localplt-*.data
file should change them to use ? on the lines for PLT calls such as the
compiler-generated outcalls, which are acceptable but not mandatory.  The
data files can have # comment lines now, so you can say something pithy
about why your machine has extra PLT entries that it really shouldn't
have.  (GCC could use a switch to treat generated libgcc calls like
attribute_hidden calls so we could get rid of these PLT entries.)


Thanks,
Roland


	* scripts/check-localplt.awk: New file.
	* elf/Makefile ($(objpfx)check-localplt.out): Use that script instead
	of diff.
	* scripts/data/localplt-generic.data: Add a comment.

diff --git a/elf/Makefile b/elf/Makefile
index a77e792..fd766c5 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -933,8 +933,7 @@ $(objpfx)check-localplt.out: $(objpfx)check-localplt \
 			     $(common-objpfx)crypt/libcrypt.so \
 			     $(check-data)
 	$(dir $<)$(notdir $<) $(filter-out $< $(check-data),$^) | \
-	  LC_ALL=C sort | \
-	  diff -u $(check-data) - > $@
+	  $(AWK) -f $(..)scripts/check-localplt.awk $(check-data) -
 endif
 
 $(objpfx)tst-dlopenrpathmod.so: $(libdl)
diff --git a/scripts/check-localplt.awk b/scripts/check-localplt.awk
new file mode 100644
index 0000000..bb1b912
--- /dev/null
+++ b/scripts/check-localplt.awk
@@ -0,0 +1,53 @@
+# This is an awk script to process the output of elf/check-localplt.
+# The first file argument is the file of expected results.
+# Each line is either a comment starting with # or it looks like:
+#	libfoo.so: function
+# or
+#	libfoo.so: function ?
+# The latter means that a PLT entry for function is optional in libfoo.so.
+# The former means one is required.
+# The second file argument is - and this (stdin) receives the output
+# of the check-localplt program.
+
+BEGIN { result = 0 }
+
+FILENAME != "-" && /^#/ { next }
+
+FILENAME != "-" {
+  if (NF != 2 && !(NF == 3 && $3 == "?")) {
+    printf "%s:%d: bad data line: %s\n", FILENAME, FNR, $0 > "/dev/stderr";
+    result = 2;
+  } else {
+    accept[$1 " " $2] = NF == 2;
+  }
+  next;
+}
+
+NF != 2 {
+  print "Unexpected output from check-localplt:", $0 > "/dev/stderr";
+  result = 2;
+  next
+}
+
+{
+  key = $1 " " $2
+  if (key in accept) {
+    delete accept[key]
+  } else {
+    print "Extra PLT reference:", $0;
+    if (result == 0)
+      result = 1;
+  }
+}
+
+END {
+  for (key in accept) {
+    if (accept[key]) {
+      # It's mandatory.
+      print "Missing required PLT reference:", key;
+      result = 1;
+    }
+  }
+
+  exit(result);
+}
diff --git a/scripts/data/localplt-generic.data b/scripts/data/localplt-generic.data
index 2219aa9..d296519 100644
--- a/scripts/data/localplt-generic.data
+++ b/scripts/data/localplt-generic.data
@@ -1,3 +1,6 @@
+# See scripts/check-localplt.awk for how this file is processed.
+# PLT use is required for the malloc family and for matherr because
+# users can define their own functions and have library internals call them.
 libc.so: calloc
 libc.so: free
 libc.so: malloc