PR ada/20548

	* common.opt (-fstack-check): Do not declare the variable here.
	(-fstack-check=): New option variant.
	* doc/invoke.texi (Code Gen Options): Document it.
	* expr.h (STACK_OLD_CHECK_PROTECT): New macro.
	(STACK_CHECK_PROTECT): Bump to 3 pages if DWARF-2 EH is used.
	(STACK_CHECK_STATIC_BUILTIN): New macro.
	* doc/tm.texi (Stack Checking): Document STACK_CHECK_STATIC_BUILTIN.
	* opts.c: Include expr.h.
	(common_handle_option) <OPT_fold_stack_check_>: New case.
	<OPT_fstack_check>: Likewise.
	* calls.c (initialize_argument_information): Use TYPE_SIZE_UNIT
	consistently in the test for variable-sized types.  Adjust for
	new behaviour of flag_stack_check.
	* explow.c: Include except.h.
	(allocate_dynamic_stack_space): Do not take into account
	STACK_CHECK_MAX_FRAME_SIZE for static builtin stack checking.
	* function.c (gimplify_parameters): Use DECL_SIZE_UNIT in the test
	for variable-sized parameters.  Treat all parameters whose size is
	greater than STACK_CHECK_MAX_VAR_SIZE as variable-sized if generic
	stack checking is enabled.
	* gimplify.c (gimplify_decl_expr): Treat non-static objects whose
	size is greater than STACK_CHECK_MAX_VAR_SIZE as variable-sized
	if generic stack checking is enabled.
	(expand_function_end): Adjust for new behaviour of flag_stack_check.
	* reload1.c (reload): Likewise.
	* stmt.c (expand_decl): Assert that all automatic variables have
	fixed size at this point and remove dead code.
	* flags.h (stack_check_type): New enumeration type.
	(flag_stack_check): Declare.
	* toplev.c (flag_stack_check): New global variable.
	* Makefile.in (opts.o): Add dependency on EXPR_H.
	(explow.o): Add dependency on except.h.
ada/
	* gcc-interface/decl.c (gnat_to_gnu_entity): Use DECL_SIZE_UNIT in the
	setjmp test consistently.  Adjust for new behaviour of flag_stack_check.
	* gcc-interface/utils2.c (build_call_alloc_dealloc): Remove redundant
	test of flag_stack_check.  Adjust for new behaviour of flag_stack_check.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@139159 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 23 insertions, 2 deletions

diff --git a/gcc/expr.h b/gcc/expr.h
index 39a51fcfe13..29b1f3e9312 100644
--- a/gcc/expr.h
+++ b/gcc/expr.h
@@ -208,10 +208,16 @@ do {								\
 
 /* Provide default values for the macros controlling stack checking.  */
 
+/* The default is neither full builtin stack checking...  */
 #ifndef STACK_CHECK_BUILTIN
 #define STACK_CHECK_BUILTIN 0
 #endif
 
+/* ...nor static builtin stack checking.  */
+#ifndef STACK_CHECK_STATIC_BUILTIN
+#define STACK_CHECK_STATIC_BUILTIN 0
+#endif
+
 /* The default interval is one page.  */
 #ifndef STACK_CHECK_PROBE_INTERVAL
 #define STACK_CHECK_PROBE_INTERVAL 4096
@@ -222,9 +228,24 @@ do {								\
 #define STACK_CHECK_PROBE_LOAD 0
 #endif
 
-/* This value is arbitrary, but should be sufficient for most machines.  */
+/* This is a kludge to try to capture the discrepancy between the old
+   mechanism (generic stack checking) and the new mechanism (static
+   builtin stack checking).  STACK_CHECK_PROTECT needs to be bumped
+   for the latter because part of the protection area is effectively
+   included in STACK_CHECK_MAX_FRAME_SIZE for the former.  */
+#ifdef STACK_CHECK_PROTECT
+#define STACK_OLD_CHECK_PROTECT STACK_CHECK_PROTECT
+#else
+#define STACK_OLD_CHECK_PROTECT \
+ (USING_SJLJ_EXCEPTIONS ? 75 * UNITS_PER_WORD : 8 * 1024)
+#endif
+
+/* Minimum amount of stack required to recover from an anticipated stack
+   overflow detection.  The default value conveys an estimate of the amount
+   of stack required to propagate an exception.  */
 #ifndef STACK_CHECK_PROTECT
-#define STACK_CHECK_PROTECT (75 * UNITS_PER_WORD)
+#define STACK_CHECK_PROTECT \
+ (USING_SJLJ_EXCEPTIONS ? 75 * UNITS_PER_WORD : 12 * 1024)
 #endif
 
 /* Make the maximum frame size be the largest we can and still only need