SRA (and perhaps other passes?) introduce “addressable” MEM_REFs to
variables that were not addressable at the time mudflap1 ran registering
valid memory ranges; when mudflap2 ran to emit the checks, it found such
MEM_REFs, marking the variables as addressable and emitting checks that
will fail at run time.
This patch refactors mem_ref_refers_to_non_mem_p so that it retains its
behavior, while introducing a variant for use by tree-mudflap.c that
assumes a variable that doesn't have its RTL set may end up in a
register.
Regstrapped on x86_64-linux-gnu. Ok to install?
Fix mudflap errors on access to SRAed variables.
From: Alexandre Oliva <aol...@redhat.com>
for gcc/ChangeLog
PR libmudflap/53952
* expr.c (mem_ref_refers_to_non_mem_p): Factor out
implementation into...
(addr_expr_of_non_mem_decl_p_1): ... this new function.
(addr_expr_of_non_mem_decl_p): New.
* tree.h (addr_expr_of_non_mem_decl_p): Declare.
* tree-mudflap.c (mf_xform_derefs_1): Don't change MEM_REFs
and TARGET_MEM_REFs that have an ADDR_EXPR of a non-mem DECL
as base operand.
---
gcc/expr.c | 45 ++++++++++++++++++++++++++++++++++++---------
gcc/tree-mudflap.c | 6 ++++++
gcc/tree.h | 3 +++
3 files changed, 45 insertions(+), 9 deletions(-)
diff --git a/gcc/expr.c b/gcc/expr.c
index 48e2581..7e86983 100644
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -4557,21 +4557,48 @@ get_bit_range (unsigned HOST_WIDE_INT *bitstart,
*bitend = *bitstart + tree_low_cst (DECL_SIZE (repr), 1) - 1;
}
+/* Returns true if ADDR is an ADDR_EXPR of a DECL that does not reside
+ in memory and has non-BLKmode. DECL_RTL must not be a MEM; if
+ DECL_RTL was not set yet, return NORTL. */
+
+static inline bool
+addr_expr_of_non_mem_decl_p_1 (tree addr, bool nortl)
+{
+ if (TREE_CODE (addr) != ADDR_EXPR)
+ return false;
+
+ tree base = TREE_OPERAND (addr, 0);
+
+ if (!DECL_P (base)
+ || TREE_ADDRESSABLE (base)
+ || DECL_MODE (base) == BLKmode)
+ return false;
+
+ if (!DECL_RTL_SET_P (base))
+ return nortl;
+
+ return (!MEM_P (DECL_RTL (base)));
+}
+
/* Returns true if the MEM_REF REF refers to an object that does not
reside in memory and has non-BLKmode. */
-static bool
+static inline bool
mem_ref_refers_to_non_mem_p (tree ref)
{
tree base = TREE_OPERAND (ref, 0);
- if (TREE_CODE (base) != ADDR_EXPR)
- return false;
- base = TREE_OPERAND (base, 0);
- return (DECL_P (base)
- && !TREE_ADDRESSABLE (base)
- && DECL_MODE (base) != BLKmode
- && DECL_RTL_SET_P (base)
- && !MEM_P (DECL_RTL (base)));
+ return addr_expr_of_non_mem_decl_p_1 (base, false);
+}
+
+/* Return TRUE iff OP is an ADDR_EXPR of a DECL that's not
+ addressable. This is very much like mem_ref_refers_to_non_mem_p,
+ but instead of the MEM_REF, it takes its base, and it doesn't
+ assume a DECL is in memory just because its RTL is not set yet. */
+
+bool
+addr_expr_of_non_mem_decl_p (tree op)
+{
+ return addr_expr_of_non_mem_decl_p_1 (op, true);
}
/* Expand an assignment that stores the value of FROM into TO. If NONTEMPORAL
diff --git a/gcc/tree-mudflap.c b/gcc/tree-mudflap.c
index 9b9c549..90d0448 100644
--- a/gcc/tree-mudflap.c
+++ b/gcc/tree-mudflap.c
@@ -877,6 +877,9 @@ mf_xform_derefs_1 (gimple_stmt_iterator *iter, tree *tp,
break;
case MEM_REF:
+ if (addr_expr_of_non_mem_decl_p (TREE_OPERAND (t, 0)))
+ return;
+
addr = fold_build_pointer_plus_loc (location, TREE_OPERAND (t, 0),
TREE_OPERAND (t, 1));
base = addr;
@@ -886,6 +889,9 @@ mf_xform_derefs_1 (gimple_stmt_iterator *iter, tree *tp,
break;
case TARGET_MEM_REF:
+ if (addr_expr_of_non_mem_decl_p (TMR_BASE (t)))
+ return;
+
addr = tree_mem_ref_addr (ptr_type_node, t);
base = addr;
limit = fold_build_pointer_plus_hwi_loc (location,
diff --git a/gcc/tree.h b/gcc/tree.h
index a830e28..9b75d36 100644
--- a/gcc/tree.h
+++ b/gcc/tree.h
@@ -6313,6 +6313,9 @@ extern unsigned HOST_WIDE_INT compute_builtin_object_size (tree, int);
succeed. */
extern int can_move_by_pieces (unsigned HOST_WIDE_INT, unsigned int);
+/* Is it an ADDR_EXPR of a DECL that's not in memory? */
+extern bool addr_expr_of_non_mem_decl_p (tree);
+
extern unsigned HOST_WIDE_INT highest_pow2_factor (const_tree);
extern tree build_personality_function (const char *);
--
Alexandre Oliva, freedom fighter http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/ FSF Latin America board member
Free Software Evangelist Red Hat Brazil Compiler Engineer
