I will make the changes Ian suggested to gospec.c and was planning to fix the sed string in gcc/configure.ac as David suggested.
I need some feedback on whether to enable the gold linker at all for split stack on platforms other than Power in gcc/configure.ac. I don't know if there are gold linker versions that should be verified for non-Power platforms. My first patch only enabled it on Power and that is what I think should be done. Those who would like to use gold with split stack for other platforms can enable it under the appropriate conditions. On 09/15/2015 01:18 PM, David Edelsohn wrote:
On Thu, Aug 27, 2015 at 5:00 PM, Lynn A. Boger <labo...@linux.vnet.ibm.com> wrote:Here is an updated patch, with a summary of the differences from my previous patch: - In my previous patch gcc configure was verifying the gold linker even if it was the default linker, but that is not necessary since in that case -fuse-ld=gold does not need to be set. Gold version checking is now only done if the alternate linker is gold and the default linker is not. - The STACK_SPLIT_STACK spec define found in gcc/gcc.c now adds -fuse-ld=gold if the gcc configure determines the alternate gold linker has split stack support. - A case statement is now used in gcc configure to verify the gold version, to make it easier for other platforms to add their checks if necessary. I don't know if other platforms require this checking; Matthias' patch did not check the version. For powerpc64 big and little endian we have to check the gold linker version because the split stack support was added recently and older gold linkers won't work. - The version checking of the gold linker was removed from the libgo configure since gcc configure has already decided if it is correct. - TARGET_CAN_SPLIT_STACK_64BIT is now defined in sysv4.h if the glibc version is correct for split stack for powerpc64 big and little endian. This define is used in go/gospec.c in the same way that TARGET_CAN_SPLIT_STACK is used now but, additionally verifies that it is a 64 bit compile. This is necessary because split stack support is not available for ppc 32 bit big endian in gcc or the gold linker. Bootstrapped and tested on x86_64, ppc64le, ppc64 (ran m32, m64 tests) 2015-08-27 Lynn Boger <labo...@linux.vnet.ibm.com> gcc/ PR target/66870 config/rs6000/sysv4.h: Define TARGET_CAN_SPLIT_STACK_64BIT based on LIBC version. config.in: Set up HAVE_GOLD_ALTERNATE. configure.ac: Define HAVE_GOLD_ALTERNATE if the version of the gold linker supports split stack. configure: Regenerate. gcc.c: Add -fuse-ld=gold to STACK_SPLIT_SPEC if HAVE_GOLD_ALTERNATE is defined. go/gospec.c: (lang_specific_driver): Use TARGET_CAN_SPLIT_STACK_64BIT to control setting of fsplit-stack and u,pthread_create options for 64 bit compiles.I don't have authority to approve for most of the patch. I noticed that the test for Gold version number is different than a similar test in another part of configure. And the sed pattern seems to be too restrictive -- it fails to extract a version number for my tests with Gold in a few different Linux distros. This should be addressed instead of silently misidentifying split stack support in some distros. - David
