From 224bb2aed0514bfa1dbfb4ee76bb2f79bd976cde Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Beno=C3=AEt=20Minisini?= <gambas@users.sourceforge.net>
Date: Sun, 18 May 2014 21:39:52 +0000
Subject: [PATCH] [INTERPRETER] * BUG: Add a small reserved area in the stack
 for the Eval() function, so   that the debugger can return the contents of a
 variable after a stack   overflow without raising a new stack overflow error
 and then crashing.

git-svn-id: svn://localhost/gambas/trunk@6276 867c0c6c-44f3-4631-809d-bfa615b0a4ec
---
 main/gbx/gbx_eval.c  | 3 +++
 main/gbx/gbx_stack.c | 3 ++-
 main/gbx/gbx_stack.h | 9 +++++++--
 3 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/main/gbx/gbx_eval.c b/main/gbx/gbx_eval.c
index 6095e28bd..8d2c4ebf4 100644
--- a/main/gbx/gbx_eval.c
+++ b/main/gbx/gbx_eval.c
@@ -104,6 +104,8 @@ bool EVAL_expression(EXPRESSION *expr, EVAL_FUNCTION func)
 	fprintf(stderr, "EVAL: %s\n", EVAL->source);
 	#endif
 
+	STACK_enable_for_eval();
+
 	nvar = EVAL->nvar;
 
 	STACK_check(nvar);
@@ -139,6 +141,7 @@ bool EVAL_expression(EXPRESSION *expr, EVAL_FUNCTION func)
 	}
 	END_TRY
 	
+	STACK_disable_for_eval();
 	EXEC_debug = debug;
 	return error;
 }
diff --git a/main/gbx/gbx_stack.c b/main/gbx/gbx_stack.c
index 455fe23c4..427bfe831 100644
--- a/main/gbx/gbx_stack.c
+++ b/main/gbx/gbx_stack.c
@@ -68,9 +68,10 @@ void STACK_init(void)
 
 	STACK_process_stack_limit = (uintptr_t)&stack - max + 65536;
 	
-  STACK_limit = (STACK_base + STACK_size);
+  STACK_limit = STACK_base + STACK_size;
   STACK_frame = (STACK_CONTEXT *)STACK_limit;
   STACK_frame_count = 0;
+	STACK_limit -= STACK_FOR_EVAL * sizeof(VALUE);
 
   SP = (VALUE *)STACK_base;
 }
diff --git a/main/gbx/gbx_stack.h b/main/gbx/gbx_stack.h
index f71402ad8..6469611f6 100644
--- a/main/gbx/gbx_stack.h
+++ b/main/gbx/gbx_stack.h
@@ -69,6 +69,8 @@ EXTERN uintptr_t STACK_process_stack_limit;
 
 #endif
 
+#define STACK_FOR_EVAL 16
+
 void STACK_init(void);
 void STACK_exit(void);
 
@@ -119,7 +121,7 @@ STACK_CONTEXT *STACK_get_frame(int frame);
 	STACK_copy(STACK_frame, _context); \
 	\
 	STACK_frame_count++; \
-	STACK_limit = (char *)STACK_frame; \
+	STACK_limit -= sizeof(STACK_CONTEXT); \
 })
 
 #define STACK_pop_frame(_context) \
@@ -127,7 +129,10 @@ STACK_CONTEXT *STACK_get_frame(int frame);
 	STACK_copy(_context, STACK_frame); \
 	STACK_frame++; \
 	STACK_frame_count--; \
-	STACK_limit = (char *)STACK_frame; \
+	STACK_limit += sizeof(STACK_CONTEXT); \
 })
 
+#define STACK_enable_for_eval() STACK_limit += STACK_FOR_EVAL * sizeof(VALUE)
+#define STACK_disable_for_eval() STACK_limit -= STACK_FOR_EVAL * sizeof(VALUE)
+
 #endif