bestack: add support for nodes resetting the stack

ir/be/bearch.h

@@ -40,6 +40,13 @@
 #include "beirg.h"
 #include "error.h"
 
+/**
+ * this constant is returned by the get_sp_bias functions if the stack
+ * is reset (usually because the frame pointer is copied to the stack
+ * pointer
+ */
+#define SP_BIAS_RESET      INT_MIN
+
 typedef enum arch_register_class_flags_t {
 	arch_register_class_flag_none      = 0,
 	/** don't do automatic register allocation for this class */

ir/be/bestack.c

@@ -183,9 +183,8 @@ static int process_stack_bias(ir_node *bl, int real_bias)
 		 * If the node modifies the stack pointer by a constant offset,
 		 * record that in the bias.
 		 */
-		ofs = arch_get_sp_bias(irn);
-
 		if (be_is_IncSP(irn)) {
+			ofs = be_get_IncSP_offset(irn);
 			/* fill in real stack frame size */
 			if (ofs == BE_STACK_FRAME_SIZE_EXPAND) {
 				ir_type *frame_type = get_irg_frame_type(irg);
@@ -217,10 +216,18 @@ static int process_stack_bias(ir_node *bl, int real_bias)
 					}
 				}
 			}
+			real_bias   += ofs;
+			wanted_bias += ofs;
+		} else {
+			ofs = arch_get_sp_bias(irn);
+			if (ofs == SP_BIAS_RESET) {
+				real_bias   = 0;
+				wanted_bias = 0;
+			} else {
+				real_bias   += ofs;
+				wanted_bias += ofs;
+			}
 		}
-
-		real_bias   += ofs;
-		wanted_bias += ofs;
 	}
 
 	assert(real_bias == wanted_bias);

ir/be/ia32/bearch_ia32.c

@@ -258,6 +258,11 @@ static int ia32_get_sp_bias(const ir_node *node)
 	if (is_ia32_Pop(node) || is_ia32_PopMem(node))
 		return -4;
 
+	if (is_ia32_Leave(node) || (be_is_Copy(node)
+	    && arch_get_irn_register(node) == &ia32_registers[REG_ESP])) {
+		return SP_BIAS_RESET;
+	}
+
 	return 0;
 }
 

ir/be/sparc/bearch_sparc.c

@@ -117,6 +117,8 @@ static int sparc_get_sp_bias(const ir_node *node)
 		 * calculates that! */
 		assert(attr->immediate_value <= -SPARC_MIN_STACKSIZE);
 		return attr->immediate_value + SPARC_MIN_STACKSIZE;
+	} else if (is_sparc_RestoreZero(node)) {
+		return SP_BIAS_RESET;
 	}
 	return 0;
 }