From 7458026b018e6635b9d1bae9ec3b9f4738c3d94a Mon Sep 17 00:00:00 2001 From: Ian Lance Taylor Date: Mon, 27 Sep 2010 19:48:20 +0000 Subject: common.opt (fsplit-stack): New option. gcc/: * common.opt (fsplit-stack): New option. * opts.c (decode_options): Set flag_split_stack to final value. * target.def (supports_split_stack): New hook. * gcc.c (STACK_SPLIT_SPEC): Define. (LINK_COMMAND_SPEC): Use STACK_SPLIT_SPEC. * doc/invoke.texi (Option Summary): Mention -fsplit-stack. (Code Gen Options): Document -fsplit-stack. * doc/extend.texi (Function Attributes): Mention no_split_stack. (Function Attributes): Document no_split_stack. * doc/tm.texi.in (Stack Smashing Protection): Add @hook TARGET_SUPPORTS_SPLIT_STACK. * doc/tm.texi: Rebuild. * function.c (thread_prologue_and_epilogue_insns): If flag_split_stack, add split stack prologue. * explow.c (allocate_dynamic_stack_space): Support -fsplit-stack. * varasm.c (saw_no_split_stack): New static variable. (assemble_start_function): Set saw_no_split_stack if the function has the no_split_stack attribute. (file_end_indicate_split_stack): New function. * output.h (file_end_indicate_split_stack): Declare. * libgcc-std.ver (GCC_4.6.0): Add -fsplit-stack support variables and function. * doc/libgcc.texi (Miscellaneous routines): Document -fsplit-stack routines. * config/i386/i386.c (ix86_option_override_internal): Don't set expand_builtin_va_start to NULL if -fsplit-stack. (ix86_function_regparm): Reduce local regparm by 1 for 32-bit -fsplit-stack. (ix86_va_start): If -fsplit-stack, get overflow pointer from scratch register set by prologue. (ix86_code_end): If -fsplit-stack, call file_end_indicate_split_stack. (ix86_supports_split_stack): New static function. (SPLIT_STACK_AVAILABLE): Define. (split_stack_prologue_scratch_regno): New static function. (split_stack_fn): New static variable. (ix86_expand_split_stack_prologue): New function. (ix86_live_on_entry): New static function. (ix86_legitimate_address_p): Handle UNSPEC_STACK_CHECK. (output_pic_addr_const): Likewise. (i386_asm_output_addr_const_extra): Likewise. (ix86_expand_call): Change return type to rtx. Return the new call instruction. (TARGET_SUPPORTS_SPLIT_STACK): Define. (TARGET_EXTRA_LIVE_ON_ENTRY): Define. * config/i386/i386.md (UNSPEC_STACK_CHECK): Define. (split_stack_prologue, split_stack_return): New insns. (split_stack_space_check): New insn. * config/i386/i386.h (struct machine_function): Add split_stack_varargs_pointer field. * config/i386/linux.h (TARGET_CAN_SPLIT_STACK): Define. (TARGET_THREAD_SPLIT_STACK_OFFSET): Define. * config/i386/linux64.h (TARGET_CAN_SPLIT_STACK): Define. (TARGET_THREAD_SPLIT_STACK_OFFSET): Define. * config/i386/i386-protos.h (ix86_expand_split_stack_prologue): Declare. (ix86_expand_call): Update declaration. gcc/c-family/: * c-common.c (c_common_attribute_table): Add no_split_stack. (handle_no_split_stack_attribute): New static function. gcc/testsuite/: * lib/target-supports.exp (check_effective_target_split_stack): New procedure. * gcc.dg/split-1.c: New test. * gcc.dg/split-2.c: New test. * gcc.dg/split-3.c: New test. * gcc.dg/split-4.c: New test. libgcc/: * generic-morestack.h: New file. * generic-morestack.c: New file. * generic-morestack-thread.c: New file. * config/i386/morestack.S: New file. * config/t-stack: New file. * config/i386/t-stack-i386: New file. * config.host (i[34567]86-*-linux* and friends): Add t-stack and i386/t-stack-i386 to tmake_file. From-SVN: r164661 --- gcc/doc/invoke.texi | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) (limited to 'gcc/doc/invoke.texi') diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index ee62b1b..bb17a0e 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -927,7 +927,7 @@ See S/390 and zSeries Options. -fshort-double -fshort-wchar @gol -fverbose-asm -fpack-struct[=@var{n}] -fstack-check @gol -fstack-limit-register=@var{reg} -fstack-limit-symbol=@var{sym} @gol --fno-stack-limit @gol +-fno-stack-limit -fsplit-stack @gol -fleading-underscore -ftls-model=@var{model} @gol -ftrapv -fwrapv -fbounds-check @gol -fvisibility} @@ -17857,6 +17857,25 @@ and grows downwards, you can use the flags @option{-Wl,--defsym,__stack_limit=0x7ffe0000} to enforce a stack limit of 128KB@. Note that this may only work with the GNU linker. +@item -fsplit-stack +@opindex fsplit-stack +Generate code to automatically split the stack before it overflows. +The resulting program has a discontiguous stack which can only +overflow if the program is unable to allocate any more memory. This +is most useful when running threaded programs, as it is no longer +necessary to calculate a good stack size to use for each thread. This +is currently only implemented for the i386 and x86_64 backends running +GNU/Linux. + +When code compiled with @option{-fsplit-stack} calls code compiled +without @option{-fsplit-stack}, there may not be much stack space +available for the latter code to run. If compiling all code, +including library code, with @option{-fsplit-stack} is not an option, +then the linker can fix up these calls so that the code compiled +without @option{-fsplit-stack} always has a large stack. Support for +this is implemented in the gold linker in GNU binutils release 2.21 +and later. + @item -fleading-underscore @opindex fleading-underscore This option and its counterpart, @option{-fno-leading-underscore}, forcibly -- cgit v1.1