#print STDERR "running: $P '$arch' '$objdump' '$objcopy' '$cc' '$ld' " .
# "'$nm' '$rm' '$mv' '$inputfile'\n";
-my %locals;
-my %convert;
+my %locals; # List of local (static) functions
+my %weak; # List of weak functions
+my %convert; # List of local functions used that needs conversion
my $type;
my $section_regex; # Find the start of a section
-my $function_regex; # Find the name of a function (return func name)
+my $function_regex; # Find the name of a function
+ # (return offset and func name)
my $mcount_regex; # Find the call site to mcount (return offset)
if ($arch eq "x86_64") {
$section_regex = "Disassembly of section";
- $function_regex = "<(.*?)>:";
+ $function_regex = "^([0-9a-fA-F]+)\\s+<(.*?)>:";
$mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\smcount([+-]0x[0-9a-zA-Z]+)?\$";
$type = ".quad";
+
+ # force flags for this arch
+ $ld .= " -m elf_x86_64";
+ $objdump .= " -M x86-64";
+ $objcopy .= " -O elf64-x86-64";
+ $cc .= " -m64";
+
} elsif ($arch eq "i386") {
$section_regex = "Disassembly of section";
- $function_regex = "<(.*?)>:";
+ $function_regex = "^([0-9a-fA-F]+)\\s+<(.*?)>:";
$mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\smcount\$";
$type = ".long";
+
+ # force flags for this arch
+ $ld .= " -m elf_i386";
+ $objdump .= " -M i386";
+ $objcopy .= " -O elf32-i386";
+ $cc .= " -m32";
+
} else {
die "Arch $arch is not supported with CONFIG_FTRACE_MCOUNT_RECORD";
}
my $text_found = 0;
my $read_function = 0;
my $opened = 0;
-my $text = "";
my $mcount_section = "__mcount_loc";
my $dirname;
my $mcount_o = $dirname . "/.tmp_mc_" . $prefix . ".o";
#
-# Step 1: find all the local symbols (static functions).
+# --globalize-symbols came out in 2.17, we must test the version
+# of objcopy, and if it is less than 2.17, then we can not
+# record local functions.
+my $use_locals = 01;
+my $local_warn_once = 0;
+my $found_version = 0;
+
+open (IN, "$objcopy --version |") || die "error running $objcopy";
+while (<IN>) {
+ if (/objcopy.*\s(\d+)\.(\d+)/) {
+ my $major = $1;
+ my $minor = $2;
+
+ $found_version = 1;
+ if ($major < 2 ||
+ ($major == 2 && $minor < 17)) {
+ $use_locals = 0;
+ }
+ last;
+ }
+}
+close (IN);
+
+if (!$found_version) {
+ print STDERR "WARNING: could not find objcopy version.\n" .
+ "\tDisabling local function references.\n";
+}
+
+
+#
+# Step 1: find all the local (static functions) and weak symbols.
+# 't' is local, 'w/W' is weak (we never use a weak function)
#
open (IN, "$nm $inputfile|") || die "error running $nm";
while (<IN>) {
if (/^[0-9a-fA-F]+\s+t\s+(\S+)/) {
$locals{$1} = 1;
+ } elsif (/^[0-9a-fA-F]+\s+([wW])\s+(\S+)/) {
+ $weak{$2} = $1;
}
}
close(IN);
+my @offsets; # Array of offsets of mcount callers
+my $ref_func; # reference function to use for offsets
+my $offset = 0; # offset of ref_func to section beginning
+
+##
+# update_funcs - print out the current mcount callers
+#
+# Go through the list of offsets to callers and write them to
+# the output file in a format that can be read by an assembler.
+#
+sub update_funcs
+{
+ return if ($#offsets < 0);
+
+ defined($ref_func) || die "No function to reference";
+
+ # A section only had a weak function, to represent it.
+ # Unfortunately, a weak function may be overwritten by another
+ # function of the same name, making all these offsets incorrect.
+ # To be safe, we simply print a warning and bail.
+ if (defined $weak{$ref_func}) {
+ print STDERR
+ "$inputfile: WARNING: referencing weak function" .
+ " $ref_func for mcount\n";
+ return;
+ }
+
+ # is this function static? If so, note this fact.
+ if (defined $locals{$ref_func}) {
+
+ # only use locals if objcopy supports globalize-symbols
+ if (!$use_locals) {
+ return;
+ }
+ $convert{$ref_func} = 1;
+ }
+
+ # Loop through all the mcount caller offsets and print a reference
+ # to the caller based from the ref_func.
+ for (my $i=0; $i <= $#offsets; $i++) {
+ if (!$opened) {
+ open(FILE, ">$mcount_s") || die "can't create $mcount_s\n";
+ $opened = 1;
+ print FILE "\t.section $mcount_section,\"a\",\@progbits\n";
+ }
+ printf FILE "\t%s %s + %d\n", $type, $ref_func, $offsets[$i] - $offset;
+ }
+}
+
#
# Step 2: find the sections and mcount call sites
#
open(IN, "$objdump -dr $inputfile|") || die "error running $objdump";
+my $text;
+
while (<IN>) {
# is it a section?
if (/$section_regex/) {
$read_function = 1;
+ # print out any recorded offsets
+ update_funcs() if ($text_found);
+
+ # reset all markers and arrays
$text_found = 0;
+ undef($ref_func);
+ undef(@offsets);
+
# section found, now is this a start of a function?
} elsif ($read_function && /$function_regex/) {
- $read_function = 0;
$text_found = 1;
- $text = $1;
- # is this function static? If so, note this fact.
- if (defined $locals{$text}) {
- $convert{$text} = 1;
- }
- # is this a call site to mcount? If so, print the offset from the section
- } elsif ($text_found && /$mcount_regex/) {
- if (!$opened) {
- open(FILE, ">$mcount_s") || die "can't create $mcount_s\n";
- $opened = 1;
- print FILE "\t.section $mcount_section,\"a\",\@progbits\n";
+ $offset = hex $1;
+ $text = $2;
+
+ # if this is either a local function or a weak function
+ # keep looking for functions that are global that
+ # we can use safely.
+ if (!defined($locals{$text}) && !defined($weak{$text})) {
+ $ref_func = $text;
+ $read_function = 0;
+ } else {
+ # if we already have a function, and this is weak, skip it
+ if (!defined($ref_func) || !defined($weak{$text})) {
+ $ref_func = $text;
+ }
}
- print FILE "\t$type $text + 0x$1\n";
+ }
+
+ # is this a call site to mcount? If so, record it to print later
+ if ($text_found && /$mcount_regex/) {
+ $offsets[$#offsets + 1] = hex $1;
}
}
+# dump out anymore offsets that may have been found
+update_funcs() if ($text_found);
+
# If we did not find any mcount callers, we are done (do nothing).
if (!$opened) {
exit(0);
git.samba.org / sfrench / cifs-2.6.git / blobdiff