~ chicken-core (chicken-5) 4f61dae9ac9842afa57ddd1bbb049bb5d32d8f61

commit 4f61dae9ac9842afa57ddd1bbb049bb5d32d8f61
Author:     felix <felix@call-with-current-continuation.org>
AuthorDate: Mon Aug 13 12:23:27 2012 +0200
Commit:     Christian Kellermann <ckeen@pestilenz.org>
CommitDate: Tue Aug 14 13:20:06 2012 +0200

    Fix computation of stack depth beyond C_stack_limit.
    
    The old way of calculating the depth could overflow if the stack is
    located very high in memory. This was causing incorrect stack-overflow
    errors on some 64-bit systems (sparc64 and x86-64). The new method
    checks whether the stack-pointer is beyond the limit computed at
    startup, including a 64k "slack" area to allow (modestly) deep
    recursions in direct-call-optimized (simple, non-allocating, not
    externally visible) procedures.
    
    Signed-off-by: Christian Kellermann <ckeen@pestilenz.org>

diff --git a/c-backend.scm b/c-backend.scm
index a7b6afe6..23bf3311 100644
--- a/c-backend.scm
+++ b/c-backend.scm
@@ -855,7 +855,7 @@
 			[else
 			 (unless direct (gen #t "C_word *a;"))
 			 (when (and direct (not unsafe) (not disable-stack-overflow-checking))
-			   (gen #t "C_stack_check;") )
+			   (gen #t "C_stack_overflow_check;") )
 			 (when looping (gen #t "loop:")) ] )
 		  (when (and external (not unsafe) (not no-argc-checks) (not customizable))
 		    ;; (not customizable) implies empty-closure
diff --git a/chicken.h b/chicken.h
index 6e9e009c..f5ce0d94 100644
--- a/chicken.h
+++ b/chicken.h
@@ -1007,17 +1007,34 @@ extern double trunc(double);
 # define C_stress                  1
 #endif
 
+#define C_stack_overflow_check    C_stack_check1(C_stack_overflow())
+
+/*XXX OBSOLETE */
+#define C_stack_check             C_stack_overflow_check
+
 #if C_STACK_GROWS_DOWNWARD
 # define C_demand(n)              (C_stress && ((C_word)(C_stack_pointer - C_stack_limit) > (n)))
 # define C_stack_probe(p)         (C_stress && ((C_word *)(p) >= C_stack_limit))
-# define C_stack_test             (!C_disable_overflow_check && (C_byte*)(C_stack_pointer) + C_STACK_RESERVE < (C_byte *)C_stack_limit)
+
+# define C_stack_check1(err)      if(!C_disable_overflow_check) {	\
+                                    do { C_byte *_sp = (C_byte*)(C_stack_pointer); \
+				      if(_sp < (C_byte *)C_stack_limit && \
+					 ((C_byte *)C_stack_limit - _sp) > C_STACK_RESERVE) \
+					err; }				\
+				    while(0);}
+
 #else
 # define C_demand(n)              (C_stress && ((C_word)(C_stack_limit - C_stack_pointer) > (n)))
 # define C_stack_probe(p)         (C_stress && ((C_word *)(p) < C_stack_limit))
-# define C_stack_test             (!C_disable_overflow_check && (C_byte*)(C_stack_pointer) - C_STACK_RESERVE > (C_byte *)C_stack_limit)
-#endif
 
-#define C_stack_check             if(C_stack_test) C_stack_overflow()
+# define C_stack_check1(err)      if(!C_disable_overflow_check) {	\
+                                    do { C_byte *_sp = (C_byte*)(C_stack_pointer); \
+				      if(_sp > (C_byte *)C_stack_limit && \
+					 (_sp - (C_byte *)C_stack_limit) > C_STACK_RESERVE) \
+					err; }				\
+				    while(0);}
+
+#endif
 
 #define C_zero_length_p(x)        C_mk_bool(C_header_size(x) == 0)
 #define C_boundp(x)               C_mk_bool(((C_SCHEME_BLOCK *)(x))->data[ 0 ] != C_SCHEME_UNBOUND)
diff --git a/runtime.c b/runtime.c
index dd1c8375..caf0e11f 100644
--- a/runtime.c
+++ b/runtime.c
@@ -3843,8 +3843,7 @@ C_regparm C_word C_fcall C_equalp(C_word x, C_word y)
   C_header header;
   C_word bits, n, i;
 
-  if(C_stack_test)
-    barf(C_CIRCULAR_DATA_ERROR, "equal?");
+  C_stack_check1(barf(C_CIRCULAR_DATA_ERROR, "equal?"));
 
  loop:
   if(x == y) return 1;