1 #!/usr/bin/perl -w 2 3 use strict; 4 use warnings; 5 6 use constant WARNING_SIZE => 512; 7 8 my $symtab = {}; 9 10 # Scan output of "objdump -w -t bin/blib.a" and build up symbol table 11 # 12 my $object; 13 while ( <> ) { 14 chomp; 15 if ( /^In archive/ ) { 16 # Do nothing 17 } elsif ( /^$/ ) { 18 # Do nothing 19 } elsif ( /^(\S+\.o):\s+file format/ ) { 20 $object = $1; 21 } elsif ( /^SYMBOL TABLE:/ ) { 22 # Do nothing 23 } elsif ( /^([0-9a-fA-F]+)\s(l|g|\s)......\s(\S+)\s+([0-9a-fA-F]+)\s+(\S+)$/ ) { 24 my $value = $1; 25 my $scope = $2; 26 my $section = $3; 27 my $size = $4; 28 my $symbol = $5; 29 $symtab->{$object}->{$symbol} = { 30 global => ( $scope ne "l" ), 31 section => ( $section eq "*UND*" ? undef : $section ), 32 value => ( $value ? hex ( $value ) : 0 ), 33 size => ( $size ? hex ( $size ) : 0 ), 34 }; 35 } else { 36 die "Unrecognized line \"$_\""; 37 } 38 } 39 40 # Add symbols that we know will be generated or required by the linker 41 # 42 foreach my $object ( keys %$symtab ) { 43 my $obj_symbol = "obj_$object"; 44 $obj_symbol =~ s/\.o$//; 45 $obj_symbol =~ s/\W/_/g; 46 $symtab->{LINKER}->{$obj_symbol} = { 47 global => 1, 48 section => undef, 49 value => 0, 50 size => 0, 51 }; 52 } 53 foreach my $link_sym qw ( __prefix _prefix _prefix_load_offset 54 _prefix_size _prefix_progbits_size _prefix_size_pgh 55 __text16 _text16 _text16_load_offset 56 _text16_size _text16_progbits_size _text16_size_pgh 57 __data16 _data16 _data16_load_offset 58 _data16_size _data16_progbits_size _data16_size_pgh 59 __text _text __data _data _textdata_load_offset 60 _textdata_size _textdata_progbits_size 61 __rodata __bss _end 62 _payload_offset _max_align 63 _load_size _load_size_pgh _load_size_sect 64 pci_vendor_id pci_device_id ) { 65 $symtab->{LINKER}->{$link_sym} = { 66 global => 1, 67 section => '*ABS*', 68 value => 0, 69 size => 0, 70 }; 71 } 72 73 # Add symbols that we know will be used by the debug system 74 # 75 foreach my $debug_sym qw ( dbg_autocolourise dbg_decolourise 76 dbg_hex_dump_da ) { 77 $symtab->{DEBUG}->{$debug_sym} = { 78 global => 1, 79 section => undef, 80 value => 0, 81 size => 0, 82 }; 83 } 84 85 # Build up requires, provides and shares symbol tables for global 86 # symbols 87 # 88 my $globals = {}; 89 while ( ( my $object, my $symbols ) = each %$symtab ) { 90 while ( ( my $symbol, my $info ) = each %$symbols ) { 91 if ( $info->{global} ) { 92 my $category; 93 if ( ! defined $info->{section} ) { 94 $category = "requires"; 95 } elsif ( $info->{section} eq "*COM*" ) { 96 $category = "shares"; 97 } else { 98 $category = "provides"; 99 } 100 $globals->{$symbol}->{$category}->{$object} = 1; 101 } 102 } 103 } 104 105 # Check for multiply defined, never-defined and unused global symbols 106 # 107 my $problems = {}; 108 while ( ( my $symbol, my $info ) = each %$globals ) { 109 my @provides = keys %{$info->{provides}}; 110 my @requires = keys %{$info->{requires}}; 111 my @shares = keys %{$info->{shares}}; 112 113 if ( ( @provides == 0 ) && ( @shares == 1 ) ) { 114 # A symbol "shared" by just a single file is actually being 115 # provided by that file; it just doesn't have an initialiser. 116 @provides = @shares; 117 @shares = (); 118 } 119 120 if ( ( @requires > 0 ) && ( @provides == 0 ) && ( @shares == 0 ) ) { 121 # No object provides this symbol, but some objects require it. 122 $problems->{$_}->{nonexistent}->{$symbol} = 1 foreach @requires; 123 } 124 125 if ( ( @requires == 0 ) && ( @provides > 0 ) ) { 126 # No object requires this symbol, but some objects provide it. 127 foreach my $provide ( @provides ) { 128 if ( $provide eq "LINKER" ) { 129 # Linker-provided symbols are exempt from this check. 130 } elsif ( $symtab->{$provide}->{$symbol}->{section} =~ /^\.tbl\./ ) { 131 # Linker tables are exempt from this check. 132 } else { 133 $problems->{$provide}->{unused}->{$symbol} = 1; 134 } 135 } 136 } 137 138 if ( ( @shares > 0 ) && ( @provides > 0 ) ) { 139 # A shared symbol is being initialised by an object 140 $problems->{$_}->{shared}->{$symbol} = 1 foreach @provides; 141 } 142 143 if ( @provides > 1 ) { 144 # A non-shared symbol is defined in multiple objects 145 $problems->{$_}->{multiples}->{$symbol} = 1 foreach @provides; 146 } 147 } 148 149 # Check for excessively large local symbols. Text and rodata symbols 150 # are exempt from this check 151 # 152 while ( ( my $object, my $symbols ) = each %$symtab ) { 153 while ( ( my $symbol, my $info ) = each %$symbols ) { 154 if ( ( ! $info->{global} ) && 155 ( ( defined $info->{section} ) && 156 ! ( $info->{section} =~ /^(\.text|\.rodata)/ ) ) && 157 ( $info->{size} >= WARNING_SIZE ) ) { 158 $problems->{$object}->{large}->{$symbol} = 1; 159 } 160 } 161 } 162 163 # Print out error messages 164 # 165 my $errors = 0; 166 my $warnings = 0; 167 foreach my $object ( sort keys %$problems ) { 168 my @nonexistent = sort keys %{$problems->{$object}->{nonexistent}}; 169 my @multiples = sort keys %{$problems->{$object}->{multiples}}; 170 my @unused = sort keys %{$problems->{$object}->{unused}}; 171 my @shared = sort keys %{$problems->{$object}->{shared}}; 172 my @large = sort keys %{$problems->{$object}->{large}}; 173 174 print "WARN $object provides unused symbol $_\n" foreach @unused; 175 $warnings += @unused; 176 print "WARN $object has large static symbol $_\n" foreach @large; 177 $warnings += @large; 178 print "ERR $object requires non-existent symbol $_\n" foreach @nonexistent; 179 $errors += @nonexistent; 180 foreach my $symbol ( @multiples ) { 181 my @other_objects = sort grep { $_ ne $object } 182 keys %{$globals->{$symbol}->{provides}}; 183 print "ERR $object provides symbol $symbol" 184 ." (also provided by @other_objects)\n"; 185 } 186 $errors += @multiples; 187 print "ERR $object misuses shared symbol $_\n" foreach @shared; 188 } 189 190 print "$errors error(s), $warnings warning(s)\n"; 191 exit ( $errors ? 1 : 0 ); 192
