Extend local PLT reference check

On x86, linker in binutils 2.26 and newer consolidates R_*_JUMP_SLOT with
R_*_GLOB_DAT relocation against the same symbol.  This patch extends
local PLT reference check to support alternate relocations.

	[BZ #18078]
	* scripts/check-localplt.awk: Support alternate relocations.
	* scripts/localplt.awk: Also check relocations in DT_RELA/DT_REL
	sections.
	* sysdeps/unix/sysv/linux/i386/localplt.data: Mark free and
	malloc entries with + REL R_386_GLOB_DAT.
	* sysdeps/x86_64/localplt.data: New file.

1 files changed, 35 insertions, 5 deletions

diff --git a/scripts/check-localplt.awk b/scripts/check-localplt.awk
index bb1b912131..3965292888 100644
--- a/scripts/check-localplt.awk
+++ b/scripts/check-localplt.awk
@@ -3,9 +3,14 @@
 # Each line is either a comment starting with # or it looks like:
 #	libfoo.so: function
 # or
+#	libfoo.so: function + {RELA|REL} RELOC
+# 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 first entry means that one is required.
+# The second entry means that one is required and relocation may also be
+# {RELA|REL} RELOC.
+# The third entry means that a PLT entry for function is optional in
+# libfoo.so.
 # The second file argument is - and this (stdin) receives the output
 # of the check-localplt program.
 
@@ -14,7 +19,10 @@ BEGIN { result = 0 }
 FILENAME != "-" && /^#/ { next }
 
 FILENAME != "-" {
-  if (NF != 2 && !(NF == 3 && $3 == "?")) {
+  if (NF == 5 && $3 == "+" && ($4 == "RELA" || $4 == "REL")) {
+    accept_type[$1 " " $2] = $4;
+    accept_reloc[$1 " " $2] = $5;
+  } else if (NF != 2 && !(NF == 3 && $3 == "?")) {
     printf "%s:%d: bad data line: %s\n", FILENAME, FNR, $0 > "/dev/stderr";
     result = 2;
   } else {
@@ -23,7 +31,7 @@ FILENAME != "-" {
   next;
 }
 
-NF != 2 {
+NF != 2 && !(NF == 4 && ($3 == "RELA" || $3 == "REL")) {
   print "Unexpected output from check-localplt:", $0 > "/dev/stderr";
   result = 2;
   next
@@ -31,7 +39,23 @@ NF != 2 {
 
 {
   key = $1 " " $2
-  if (key in accept) {
+  if ($3 == "RELA" || $3 == "REL") {
+    # Entries like:
+    # libc.so: free + RELA R_X86_64_GLOB_DAT
+    # may be ignored.
+    if (key in accept_type && accept_type[key] == $3 && accept_reloc[key] == $4) {
+      # Match
+      # libc.so: free + RELA R_X86_64_GLOB_DAT
+      delete accept_type[key]
+    }
+  } else if (NF == 2 && key in accept_reloc) {
+    # Match
+    # libc.so: free
+    # against
+    # libc.so: free + RELA R_X86_64_GLOB_DAT
+    if (key in accept_type)
+      delete accept_type[key]
+  } else if (key in accept) {
     delete accept[key]
   } else {
     print "Extra PLT reference:", $0;
@@ -49,5 +73,11 @@ END {
     }
   }
 
+  for (key in accept_type) {
+    # It's mandatory.
+    print "Missing required PLT or " accept_reloc[key] " reference:", key;
+    result = 1;
+  }
+
   exit(result);
 }