Re: [PATCH 6/9] tracing: recordmcount.pl Exit early if no work todo

From: Steven Rostedt
Date: Tue Oct 27 2009 - 16:26:30 EST


On Tue, 2009-10-27 at 15:02 +0800, Li Hong wrote:
> >From 1589563d8113db41fa77dd657459b563dcecd389 Mon Sep 17 00:00:00 2001
> From: Li Hong <lihong.hi@xxxxxxxxx>
> Date: Tue, 27 Oct 2009 13:13:37 +0800
> Subject: [PATCH] tracing: recordmcount.pl Exit early if no work to do
>
> Also keep the global symbols and use it to check if no work to do, exit
> early.

How many files does this fall out of? This looks like added complexity
for no real gain.

-- Steve

>
> Signed-off-by: Li Hong <lihong.hi@xxxxxxxxx>
>
> diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl
> index a6585b6..d750da8 100755
> --- a/scripts/recordmcount.pl
> +++ b/scripts/recordmcount.pl
> @@ -91,7 +91,7 @@
> #
> # Here are the steps we take:
> #
> -# 1) Record all the local symbols by using 'nm'
> +# 1) Record all the global, local and weak symbols by using 'nm'
> # 2) Use objdump to find all the call site offsets and sections for
> # mcount.
> # 3) Compile the list into its own object.
> @@ -143,12 +143,15 @@ $mv = "mv" if ((length $mv) == 0);
> #print STDERR "running: $P '$arch' '$objdump' '$objcopy' '$cc' '$ld' " .
> # "'$nm' '$rm' '$mv' '$inputfile'\n";
>
> +my %globals; # List of global functions
> 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 $nm_regex; # Find the local functions (return function)
> +my $global_regex; # Match a global function (return function)
> +my $local_regex; # Match a local function (return function)
> +my $weak_regex; # Match a weak function (return function)
> my $section_regex; # Find the start of a section
> my $function_regex; # Find the name of a function
> # (return offset and func name)
> @@ -190,7 +193,9 @@ if ($arch eq "x86") {
> # We base the defaults off of i386, the other archs may
> # feel free to change them in the below if statements.
> #
> -$nm_regex = "^[0-9a-fA-F]+\\s+t\\s+(\\S+)";
> +$global_regex = "^[0-9a-fA-F]+\\s+T\\s+(\\S+)";
> +$local_regex = "^[0-9a-fA-F]+\\s+t\\s+(\\S+)";
> +$weak_regex = "^[0-9a-fA-F]+\\s+([wW])\\s+(\\S+)";
> $section_regex = "Disassembly of section\\s+(\\S+):";
> $function_regex = "^([0-9a-fA-F]+)\\s+<(.*?)>:";
> $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\smcount\$";
> @@ -239,7 +244,8 @@ if ($arch eq "x86_64") {
> $cc .= " -m32";
>
> } elsif ($arch eq "powerpc") {
> - $nm_regex = "^[0-9a-fA-F]+\\s+t\\s+(\\.?\\S+)";
> + $global_regex = "^[0-9a-fA-F]+\\s+T\\s+(\\.?\\S+)";
> + $local_regex = "^[0-9a-fA-F]+\\s+t\\s+(\\.?\\S+)";
> $function_regex = "^([0-9a-fA-F]+)\\s+<(\\.?.*?)>:";
> $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s\\.?_mcount\$";
>
> @@ -314,19 +320,24 @@ my $mcount_o = $dirname . "/.tmp_mc_" . $prefix . ".o";
> check_objcopy();
>
> #
> -# Step 1: find all the local (static functions) and weak symbols.
> -# 't' is local, 'w/W' is weak (we never use a weak function)
> +# Step 1: find all the global and local (static functions) and weak symbols.
> +# 'T' is global 't' is local, 'w/W' is weak
> #
> open (IN, "$nm $inputfile|") || die "error running $nm";
> while (<IN>) {
> - if (/$nm_regex/) {
> + if (/$global_regex/) {
> + $globals{$1} = 1;
> + } elsif (/$local_regex/) {
> $locals{$1} = 1;
> - } elsif (/^[0-9a-fA-F]+\s+([wW])\s+(\S+)/) {
> + } elsif (/$weak_regex/) {
> $weak{$2} = $1;
> }
> }
> close(IN);
>
> +# Exit early if no work to do
> +exit(0) unless (%globals or (%locals and $can_use_local));
> +
> 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

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