diff -r 75a03a4cfbca -r 41ff671ed8cf make/autoconf/flags-cflags.m4 --- a/make/autoconf/flags-cflags.m4 Wed Jun 13 20:11:18 2018 +0200 +++ b/make/autoconf/flags-cflags.m4 Wed Jun 13 07:53:27 2018 +0200 @@ -573,22 +573,24 @@ # '-qpic' defaults to 'qpic=small'. This means that the compiler generates only # one instruction for accessing the TOC. If the TOC grows larger than 64K, the linker # will have to patch this single instruction with a call to some out-of-order code which - # does the load from the TOC. This is of course slow. But in that case we also would have + # does the load from the TOC. This is of course slower, and we also would have # to use '-bbigtoc' for linking anyway so we could also change the PICFLAG to 'qpic=large'. # With 'qpic=large' the compiler will by default generate a two-instruction sequence which # can be patched directly by the linker and does not require a jump to out-of-order code. - # Another alternative instead of using 'qpic=large -bbigtoc' may be to use '-qminimaltoc' - # instead. This creates a distinct TOC for every compilation unit (and thus requires two - # loads for accessing a global variable). But there are rumors that this may be seen as a - # 'performance feature' because of improved code locality of the symbols used in a - # compilation unit. - PICFLAG="-qpic" + # + # Since large TOC causes perf. overhead, only pay it where we must. Currently this is + # for all libjvm variants (both gtest and normal) but no other binaries. So, build + # libjvm with -qpic=large and link with -bbigtoc. + JVM_PICFLAG="-qpic=large" + JDK_PICFLAG="-qpic" elif test "x$TOOLCHAIN_TYPE" = xmicrosoft; then PICFLAG="" fi - JVM_PICFLAG="$PICFLAG" - JDK_PICFLAG="$PICFLAG" + if test "x$TOOLCHAIN_TYPE" != xxlc; then + JVM_PICFLAG="$PICFLAG" + JDK_PICFLAG="$PICFLAG" + fi if test "x$OPENJDK_TARGET_OS" = xmacosx; then # Linking is different on MacOSX