From 48b14f5076a521887a2286eb84e6b51de6c50fd8 Mon Sep 17 00:00:00 2001 From: ian Date: Mon, 27 Sep 2010 19:48:20 +0000 Subject: 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. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@164661 138bc75d-0d04-0410-961f-82ee72b054a4 --- gcc/doc/libgcc.texi | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) (limited to 'gcc/doc/libgcc.texi') diff --git a/gcc/doc/libgcc.texi b/gcc/doc/libgcc.texi index 8ead53d90a9..5be6c306729 100644 --- a/gcc/doc/libgcc.texi +++ b/gcc/doc/libgcc.texi @@ -2262,3 +2262,43 @@ document me! @deftypefn {Runtime Function} void __clear_cache (char *@var{beg}, char *@var{end}) This function clears the instruction cache between @var{beg} and @var{end}. @end deftypefn + +@subsection Split stack functions and variables +@deftypefn {Runtime Function} {void *} __splitstack_find (void *@var{segment_arg}, @ +void *@var{sp}, size_t @var{len}, void **@var{next_segment}, @ +void **@var{next_sp}, void **@var{initial_sp}) +When using @option{-fsplit-stack}, this call may be used to iterate +over the stack segments. It may be called like this: +@smallexample + void *next_segment = NULL; + void *next_sp = NULL; + void *initial_sp = NULL; + void *stack; + size_t stack_size; + while ((stack = __splitstack_find (next_segment, next_sp, + &stack_size, &next_segment, + &next_sp, &initial_sp)) + != NULL) + @{ + /* Stack segment starts at stack and is + stack_size bytes long. */ + @} +@end smallexample + +There is no way to iterate over the stack segments of a different +thread. However, what is permitted is for one thread to call this +with the @var{segment_arg} and @var{sp} arguments NULL, to pass +@var{next_segment}, @var{next_sp}, and @var{initial_sp} to a different +thread, and then to suspend one way or another. A different thread +may run the subsequent @code{__splitstack_find} iterations. Of +course, this will only work if the first thread is suspended while the +second thread is calling @code{__splitstack_find}. If not, the second +thread could be looking at the stack while it is changing, and +anything could happen. +@end deftypefn + +@defvar __morestack_segments +@defvarx __morestack_current_segment +@defvarx __morestack_initial_sp +Internal variables used by the @option{-fsplit-stack} implementation. +@end defvar -- cgit v1.2.1