re PR middle-end/29683 (Arg split between stack/regs can cause stack corruption)

2007-03-01  Josh Conner  <jconner@apple.com>

	PR middle-end/29683
	* calls.c (compute_argument_addresses): Set stack and stack_slot
	for partial args, too.
	(store_one_arg): Use locate.size.constant for the size when
	generating a save_area.

2007-03-01  Josh Conner  <jconner@apple.com>

	PR middle-end/29683
	* gcc.dg/pr29683.c: New.

From-SVN: r120425

4 files changed, 94 insertions, 8 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b59cc9a..be703c7 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2007-01-03  Josh Conner  <jconner@apple.com>
+
+	PR middle-end/29683
+	* calls.c (compute_argument_addresses): Set stack and stack_slot
+	for partial args, too.
+	(store_one_arg): Use locate.size.constant for the size when
+	generating a save_area.
+
 2007-01-03  Robert Kennedy <jimbob@google.com>
 
 	* tree-cfg.c (tree_merge_blocks): Release SSA_NAME phi results
diff --git a/gcc/calls.c b/gcc/calls.c
index bdb8167..c0d1f8c 100644
--- a/gcc/calls.c
+++ b/gcc/calls.c
@@ -1355,9 +1355,13 @@ compute_argument_addresses (struct arg_data *args, rtx argblock, int num_actuals
 	  rtx slot_offset = ARGS_SIZE_RTX (args[i].locate.slot_offset);
 	  rtx addr;
 	  unsigned int align, boundary;
+	  unsigned int units_on_stack = 0;
+	  enum machine_mode partial_mode = VOIDmode;
 
 	  /* Skip this parm if it will not be passed on the stack.  */
-	  if (! args[i].pass_on_stack && args[i].reg != 0)
+	  if (! args[i].pass_on_stack
+	      && args[i].reg != 0
+	      && args[i].partial == 0)
 	    continue;
 
 	  if (GET_CODE (offset) == CONST_INT)
@@ -1366,9 +1370,23 @@ compute_argument_addresses (struct arg_data *args, rtx argblock, int num_actuals
 	    addr = gen_rtx_PLUS (Pmode, arg_reg, offset);
 
 	  addr = plus_constant (addr, arg_offset);
-	  args[i].stack = gen_rtx_MEM (args[i].mode, addr);
-	  set_mem_attributes (args[i].stack,
-			      TREE_TYPE (args[i].tree_value), 1);
+
+	  if (args[i].partial != 0)
+	    {
+	      /* Only part of the parameter is being passed on the stack.
+		 Generate a simple memory reference of the correct size.  */
+	      units_on_stack = args[i].locate.size.constant;
+	      partial_mode = mode_for_size (units_on_stack * BITS_PER_UNIT,
+					    MODE_INT, 1);
+	      args[i].stack = gen_rtx_MEM (partial_mode, addr);
+	      set_mem_size (args[i].stack, GEN_INT (units_on_stack));
+	    }
+	  else
+	    {
+	      args[i].stack = gen_rtx_MEM (args[i].mode, addr);
+	      set_mem_attributes (args[i].stack,
+				  TREE_TYPE (args[i].tree_value), 1);
+	    }
 	  align = BITS_PER_UNIT;
 	  boundary = args[i].locate.boundary;
 	  if (args[i].locate.where_pad != downward)
@@ -1386,9 +1404,21 @@ compute_argument_addresses (struct arg_data *args, rtx argblock, int num_actuals
 	    addr = gen_rtx_PLUS (Pmode, arg_reg, slot_offset);
 
 	  addr = plus_constant (addr, arg_offset);
-	  args[i].stack_slot = gen_rtx_MEM (args[i].mode, addr);
-	  set_mem_attributes (args[i].stack_slot,
-			      TREE_TYPE (args[i].tree_value), 1);
+
+	  if (args[i].partial != 0)
+	    {
+	      /* Only part of the parameter is being passed on the stack.
+		 Generate a simple memory reference of the correct size.
+	       */
+	      args[i].stack_slot = gen_rtx_MEM (partial_mode, addr);
+	      set_mem_size (args[i].stack_slot, GEN_INT (units_on_stack));
+	    }
+	  else
+	    {
+	      args[i].stack_slot = gen_rtx_MEM (args[i].mode, addr);
+	      set_mem_attributes (args[i].stack_slot,
+				  TREE_TYPE (args[i].tree_value), 1);
+	    }
 	  set_mem_align (args[i].stack_slot, args[i].locate.boundary);
 
 	  /* Function incoming arguments may overlap with sibling call
@@ -4056,7 +4086,7 @@ store_one_arg (struct arg_data *arg, rtx argblock, int flags,
 		  arg->save_area = assign_temp (nt, 0, 1, 1);
 		  preserve_temp_slots (arg->save_area);
 		  emit_block_move (validize_mem (arg->save_area), stack_area,
-				   expr_size (arg->tree_value),
+				   GEN_INT (arg->locate.size.constant),
 				   BLOCK_OP_CALL_PARM);
 		}
 	      else
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index daab71d..2406668 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2007-01-03  Josh Conner  <jconner@apple.com>
+
+	PR middle-end/29683
+	* gcc.dg/pr29683.c: New.
+
 2007-01-03  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/28217
diff --git a/gcc/testsuite/gcc.dg/pr29683.c b/gcc/testsuite/gcc.dg/pr29683.c
new file mode 100644
index 0000000..4bed679
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr29683.c
@@ -0,0 +1,43 @@
+/* { dg-do run } */
+/* { dg-options "-Os -fno-inline-functions" } */
+
+void abort (void);
+
+typedef struct {
+  int x[7];
+} agg7;
+
+typedef struct {
+  int mbr1;
+  int mbr2;
+} agg2;
+
+int expected = 31415;
+agg7 filler;
+
+int GetConst (agg7 filler, agg2 split)
+{
+  return expected;
+}
+
+void VerifyValues (agg7 filler, int last_reg, int first_stack, int second_stack)
+{
+  if (first_stack != 123 || second_stack != expected)
+    abort ();
+}
+
+void RunTest (agg2 a)
+{
+  int result;
+	
+  result = GetConst (filler, a);
+  VerifyValues (filler, 0, a.mbr1, result);
+}
+
+int main(void)
+{
+  agg2 result = {123, 456};
+  RunTest (result);
+  return 0;
+}
+