re PR target/10127 (-fstack-check let's program crash)

	PR target/10127
	PR ada/20548
	* expr.h (STACK_CHECK_PROBE_INTERVAL): Delete.
	(STACK_CHECK_PROBE_INTERVAL_EXP): New macro.
	(STACK_CHECK_MOVING_SP): Likewise.
	* system.h (STACK_CHECK_PROBE_INTERVAL): Poison it.
	* doc/tm.texi (Stack Checking): Delete STACK_CHECK_PROBE_INTERVAL.
	Document STACK_CHECK_PROBE_INTERVAL_EXP and STACK_CHECK_MOVING_SP.
	* doc/md.texi (Standard Pattern Names): Tweak entry of CHECK_STACK.
	Document PROBE_STACK.
	* explow.c (anti_adjust_stack_and_probe): New function.
	(allocate_dynamic_stack_space): Do not directly allocate space if
	STACK_CHECK_MOVING_SP, instead invoke above function.
	(emit_stack_probe): Handle probe_stack insn.
	(PROBE_INTERVAL): New macro.
	(STACK_GROW_OPTAB): Likewise.
	(STACK_GROW_OFF): Likewise.
	(probe_stack_range): Use Pmode and memory_address consistently.  Fix
	loop condition in the small constant case.  Rewrite in the general
	case to be immune to wraparounds.  Make sure the address of probes
	is valid.  Try to use [base + disp] addressing mode if possible.
	* ira.c (setup_eliminable_regset): Set frame_pointer_needed if stack
	checking is enabled and STACK_CHECK_MOVING_SP.
	* rtlanal.c (may_trap_p_1) <MEM>: If stack checking is enabled,
	return 1 for volatile references to the stack pointer.
	* tree.c (build_common_builtin_nodes): Do not set ECF_NOTHROW on
	__builtin_alloca if stack checking is enabled.
	* unwind-dw2.c (uw_identify_context): Take into account whether the
	context is that of a signal frame or not.
	* config/i386/linux.h (STACK_CHECK_MOVING_SP): Define to 1.
	* config/i386/linux64.h (STACK_CHECK_MOVING_SP): Likewise.

From-SVN: r153877

1 files changed, 13 insertions, 5 deletions

diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
index dcfba92..2974dcf 100644
--- a/gcc/doc/md.texi
+++ b/gcc/doc/md.texi
@@ -5037,11 +5037,19 @@ operations in addition to updating the stack pointer.
 @item @samp{check_stack}
 If stack checking cannot be done on your system by probing the stack with
 a load or store instruction (@pxref{Stack Checking}), define this pattern
-to perform the needed check and signaling an error if the stack
-has overflowed.  The single operand is the location in the stack furthest
-from the current stack pointer that you need to validate.  Normally,
-on machines where this pattern is needed, you would obtain the stack
-limit from a global or thread-specific variable or register.
+to perform the needed check and signal an error if the stack has overflowed.
+The single operand is the address in the stack furthest from the current
+stack pointer that you need to validate.  Normally, on machines where this
+pattern is needed, you would obtain the stack limit from a global or
+thread-specific variable or register.
+
+@cindex @code{probe_stack} instruction pattern
+@item @samp{probe_stack}
+If stack checking can be done on your system by probing the stack but doing
+it with a load or store instruction is not optimal (@pxref{Stack Checking}),
+define this pattern to do the probing differently and signal an error if
+the stack has overflowed.  The single operand is the memory location in the
+stack that needs to be probed.
 
 @cindex @code{nonlocal_goto} instruction pattern
 @item @samp{nonlocal_goto}