1#! @PERL@ 2 3# This script handles linking the tool executables on Linux, 4# statically and at an alternative load address. 5# 6# Linking statically sidesteps all sorts of complications to do with 7# having two copies of the dynamic linker (valgrind's and the 8# client's) coexisting in the same process. The alternative load 9# address is needed because Valgrind itself will load the client at 10# whatever address it specifies, which is almost invariably the 11# default load address. Hence we can't allow Valgrind itself (viz, 12# the tool executable) to be loaded at that address. 13# 14# Unfortunately there's no standard way to do 'static link at 15# alternative address', so these link_tool_exe_*.in scripts handle 16# the per-platform hoop-jumping. 17# 18# What we get passed here is: 19# first arg 20# the alternative load address 21# all the rest of the args 22# the gcc invokation to do the final link, that 23# the build system would have done, left to itself 24# 25# We just let the script 'die' if something is wrong, rather than do 26# proper error reporting. We don't expect the users to run this 27# directly. It is only run as part of the build process, with 28# carefully constrained inputs. 29# 30# Linux specific complications: 31# 32# - need to support both old GNU ld and gold: use -Ttext= to 33# set the text segment address. 34# 35# - need to pass --build-id=none (that is, -Wl,--build-id=none to 36# gcc) if it accepts it, to ensure the linker doesn't add a 37# notes section which ends up at the default load address and 38# so defeats our attempts to keep that address clear for the 39# client. However, older linkers don't support this flag, so it 40# is tested for by configure.in and is shipped to us as part of 41# argv[2 ..]. 42# 43# 44# So: what we actually do: 45# 46# pass the specified command to the linker as-is, except, add 47# "-static" and "-Ttext=<argv[1]>" to it. 48# 49 50use warnings; 51use strict; 52 53# expect at least: alt-load-address gcc -o foo bar.o 54die "Not enough arguments" 55 if (($#ARGV + 1) < 5); 56 57my $ala = $ARGV[0]; 58 59# check for plausible-ish alt load address 60die "Bogus alt-load address" 61 if (length($ala) < 3 || index($ala, "0x") != 0); 62 63# The cc invokation to do the final link 64my $cc = $ARGV[1]; 65 66# and the 'restargs' are argv[2 ..] 67 68# so, build up the complete command here: 69# 'cc' -static -Ttext='ala' 'restargs' 70 71# For mips we need to use "--section-start=.reginfo=$ala" because 72# "--section-start=.reginfo=$ala" will put all the sections to the 73# specificed address ($ala) 74my $x=`$cc -v 2>&1 | grep Target | sed 's/Target: //g'`; 75my $arch=substr($x, 0, index($x, '-')); 76my $cmd; 77 78if (($arch eq 'mips') || ($arch eq 'mipsel')) { 79 $cmd = "$cc -static -Wl,--section-start=.reginfo=$ala"; 80} else { 81 $cmd = "$cc -static -Wl,-Ttext=$ala"; 82} 83 84# Add the rest of the parameters 85foreach my $n (2 .. $#ARGV) { 86 $cmd = "$cmd $ARGV[$n]"; 87} 88 89#print "link_tool_exe_linux: $cmd\n"; 90 91 92# Execute the command: 93my $r = system("$cmd"); 94 95if ($r == 0) { 96 exit 0; 97} else { 98 exit 1; 99} 100