This patch corrects CO-RE generation for the cases where an expression
starts with a non-CO-RE access, but in the middle it requires to
generate CO-RE to correctly compute the access location.
It fixes it by splitting the expression into their CO-RE and non-CO-RE
counterparts. It performs this by walking gimple expressions, and for
each field access to which its type is a struct or union, it verifies if
both the types for the base and field are attributed similarly.
Otherwise, it splits the expression at this location by creating a
temporary variable and performing any required pointer conversions.
This smaller expressions are converted to CO-RE in the subsequent
gimple walker.
There is no way in GCC to distinguish nested struct/union definitions
from non-nested ones.
This patch simplifies code and enforces that all preserve_access_index
structs/unions would be attributed explicity.
Previous approach was error prone as it would extend CO-RE accesses to
structures which would not be attributed.
All GCC BPF dejagnu passes tests:
# of expected passes 553
# of expected failures 6
kernel-next bpf selftests:
Summary: 528/4794 PASSED, 113 SKIPPED, 151 FAILED
BPF selftests were execyted with the following result:
gcc/ChangeLog:
PR target/120241
* config/bpf/core-builtins.cc
(is_attr_preserve_access): Correct for pointer types.
(maybe_get_base_for_field_expr, core_access_index_map,
core_access_clean, core_is_access_index, core_mark_as_access_index):
Remove.
(make_gimple_core_safe_access_index): Remove call to
core_is_access_index.
(callback_find_next_split_location, core_should_split_expr,
find_next_split_location, gimple_core_early_split_expr): Add
function to split expressions in CO-RE and non-CO-RE
expressions.
(execute_lower_bpf_core): Adapt to new code.
gcc/testsuite/ChangeLog:
* gcc.target/bpf/core-attr-3.c: Add attribute.
* gcc.target/bpf/core-attr-4.c: Add attribute.
* gcc.target/bpf/core-attr-5.c: Add attribute.
* gcc.target/bpf/core-attr-6.c: Add attribute.
* gcc.target/bpf/core-attr-7.c: New test.
* gcc.target/bpf/core-attr-calls.c: Adapt.
---
gcc/config/bpf/core-builtins.cc | 187 +++++++++++-------
gcc/gimplify.cc | 2 +-
gcc/testsuite/gcc.target/bpf/core-attr-3.c | 4 +-
gcc/testsuite/gcc.target/bpf/core-attr-4.c | 4 +-
gcc/testsuite/gcc.target/bpf/core-attr-5.c | 2 +-
gcc/testsuite/gcc.target/bpf/core-attr-6.c | 4 +-
gcc/testsuite/gcc.target/bpf/core-attr-7.c | 150 ++++++++++++++
.../gcc.target/bpf/core-attr-calls.c | 4 +-
8 files changed, 273 insertions(+), 84 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/bpf/core-attr-7.c
diff --git a/gcc/config/bpf/core-builtins.cc b/gcc/config/bpf/core-builtins.cc
index 152da94a9761..16ee7f453bab 100644
--- a/gcc/config/bpf/core-builtins.cc
+++ b/gcc/config/bpf/core-builtins.cc
@@ -324,8 +324,13 @@ is_attr_preserve_access (tree t)
TYPE_ATTRIBUTES (TREE_TYPE (base)));
if (TREE_CODE (base) == MEM_REF)
- return lookup_attribute ("preserve_access_index",
- TYPE_ATTRIBUTES (TREE_TYPE (base)));
+ {
+ tree type = TREE_TYPE (base);
+ if (POINTER_TYPE_P (type))
+ type = TREE_TYPE (type);
+ return lookup_attribute ("preserve_access_index",
+ TYPE_ATTRIBUTES (type));
+ }
if (TREE_CODE (t) == COMPONENT_REF)
{
@@ -1710,68 +1715,6 @@ bpf_output_core_reloc (rtx *operands, int nr_ops)
}
}
-static tree
-maybe_get_base_for_field_expr (tree expr)
-{
- poly_int64 bitsize, bitpos;
- tree var_off;
- machine_mode mode;
- int sign, reverse, vol;
-
- if (expr == NULL_TREE)
- return NULL_TREE;
-
- return get_inner_reference (expr, &bitsize, &bitpos, &var_off, &mode,
- &sign, &reverse, &vol);
-}
-
-/* Access functions to mark sub expressions as attributed with
- __preserve_access_index.
- This is required since in gimple format, in order to convert an expression
as
- CO-RE safe, we must create multiple gimple statements.
- Also, only the type of the base of the expression might be attributed with
- __preserve_access_index. Nevertheless all the consecutive accesses to this
- attributed node should also be converted to CO-RE safe.
- Any LHS assigned values with CO-RE converted expressions are marked and
- any uses of these values are later checked for further convertion.
- The core_access_index_map functions allow to mark this nodes for later
- convertion to CO-RE.
- This mechanism are used by make_gimple_core_safe_access_index. */
-
-static GTY(()) hash_map<tree, tree> *core_access_index_map = NULL;
-
-static void
-core_access_clean (void)
-{
- if (core_access_index_map == NULL)
- core_access_index_map = hash_map<tree, tree>::create_ggc (10);
- core_access_index_map->empty ();
-}
-
-static bool
-core_is_access_index (tree expr)
-{
- if (TREE_CODE (expr) == MEM_REF
- || TREE_CODE (expr) == INDIRECT_REF)
- expr = TREE_OPERAND (expr, 0);
-
- tree *def = core_access_index_map->get (expr);
- if (def)
- return true;
- return false;
-}
-
-static void
-core_mark_as_access_index (tree expr)
-{
- if (TREE_CODE (expr) == MEM_REF
- || TREE_CODE (expr) == INDIRECT_REF)
- expr = TREE_OPERAND (expr, 0);
-
- if (core_access_index_map->get (expr) == NULL)
- core_access_index_map->put (expr, NULL_TREE);
-}
-
/* This function is an adaptation of make_core_safe_access_index but to be used
in gimple format trees. It is used by execute_lower_bpf_core, when
traversing the gimple tree looking for nodes that would have its type
@@ -1792,8 +1735,7 @@ make_gimple_core_safe_access_index (tree *tp,
patch = &(TREE_OPERAND (*tp, 0));
tree orig_type = TREE_TYPE (*patch);
- if ((is_attr_preserve_access (*patch)
- || core_is_access_index (maybe_get_base_for_field_expr (*patch)))
+ if (is_attr_preserve_access (*patch)
&& (n = compute_field_expr (*patch, NULL, &valid, NULL)) > 0
&& valid == true)
{
@@ -1822,13 +1764,109 @@ make_gimple_core_safe_access_index (tree *tp,
wi->changed = true;
*walk_subtrees = false;
+ }
+ return NULL_TREE;
+}
- tree lhs;
- if (!wi->is_lhs
- && gimple_code (wi->stmt) != GIMPLE_CALL
- && (lhs = gimple_get_lhs (wi->stmt)) != NULL_TREE)
- core_mark_as_access_index (lhs);
+static bool
+core_should_split_expr (tree t)
+{
+ tree type = TREE_TYPE (t);
+ if (TREE_CODE (type) != RECORD_TYPE
+ && TREE_CODE (type) != UNION_TYPE)
+ return false;
+
+ if (TREE_CODE (t) == COMPONENT_REF)
+ {
+ tree base = TREE_OPERAND (t, 0);
+
+ bool base_is_attr = lookup_attribute ("preserve_access_index",
+ TYPE_ATTRIBUTES (TREE_TYPE (base)));
+ bool cur_is_attr = lookup_attribute ("preserve_access_index",
+ TYPE_ATTRIBUTES (TREE_TYPE (t)));
+
+ if (base_is_attr != cur_is_attr)
+ return true;
}
+ return false;
+}
+
+static tree
+callback_find_next_split_location (tree *tp,
+ int *walk_subtrees ATTRIBUTE_UNUSED,
+ void *data)
+{
+ tree **core_base_pointer = (tree **) data;
+
+ bool should_split = core_should_split_expr (*tp);
+
+ if (should_split == true)
+ {
+ *core_base_pointer = tp;
+ return *tp;
+ }
+ else
+ /* Keep walking the expression. */
+ return NULL_TREE;
+}
+
+static tree *
+find_next_split_location (tree *tp)
+{
+
+ tree *core_base_pointer = NULL;
+ walk_tree (tp, callback_find_next_split_location, &core_base_pointer, NULL);
+ return core_base_pointer;
+}
+
+static tree
+gimple_core_early_split_expr (tree *tp,
+ int *walk_subtrees,
+ void *data)
+{
+ struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
+ tree *split_loc = tp;
+
+ /* Find the next split location within expression tree. */
+ tree *expr = NULL;
+ bool is_first = true;
+ while ((expr = find_next_split_location (split_loc)) != NULL)
+ {
+ gimple_seq before = NULL;
+
+ if (*expr == *split_loc && is_first == true)
+ break;
+ is_first = false;
+
+ push_gimplify_context ();
+ split_loc = &TREE_OPERAND (*expr, 0);
+
+ tree rhs = *expr;
+ bool pointer_base = false;
+ if (!POINTER_TYPE_P (TREE_TYPE (rhs)))
+ {
+ rhs = fold_build1 (ADDR_EXPR,
+ build_pointer_type (TREE_TYPE (*expr)),
+ *expr);
+ pointer_base = true;
+ }
+ tree lhs = create_tmp_var_raw (TREE_TYPE (rhs), "core_split");
+ gimple_add_tmp_var (lhs);
+ gimplify_assign (lhs, rhs, &before);
+
+ if (pointer_base == true)
+ lhs = fold_build2 (MEM_REF, TREE_TYPE (lhs), lhs,
+ build_int_cst (ptr_type_node, 0));
+ *expr = lhs;
+
+ gsi_insert_seq_before (&(wi->gsi), before, GSI_NEW_STMT);
+ pop_gimplify_context (NULL);
+ }
+
+ /* Never traverse subtrees, as find_next_split_location already does it. */
+ *walk_subtrees = false;
+
+ /* Keep traverve all the other tree expressions in gimple. */
return NULL_TREE;
}
@@ -1851,10 +1889,11 @@ execute_lower_bpf_core (void)
gimple_seq body = gimple_body (current_function_decl);
struct walk_stmt_info wi;
- core_access_clean ();
-
memset (&wi, 0, sizeof (wi));
- wi.info = NULL;
+
+ /* Early split to guarantee base of expression is a preserve_access_index
+ structure. */
+ walk_gimple_seq_mod (&body, NULL, gimple_core_early_split_expr, &wi);
/* Split preserve_access_index expressions when needed. */
walk_gimple_seq_mod (&body, NULL, make_gimple_core_safe_access_index, &wi);
diff --git a/gcc/gimplify.cc b/gcc/gimplify.cc
index d8725e4c5e20..5e8a1ac352de 100644
--- a/gcc/gimplify.cc
+++ b/gcc/gimplify.cc
@@ -2498,7 +2498,7 @@ last_stmt_in_scope (gimple *stmt)
if (!stmt)
return NULL;
- auto last_stmt_in_seq = [] (gimple_seq s)
+ auto last_stmt_in_seq = [] (gimple_seq s)
{
gimple_seq_node n;
for (n = gimple_seq_last (s);
diff --git a/gcc/testsuite/gcc.target/bpf/core-attr-3.c
b/gcc/testsuite/gcc.target/bpf/core-attr-3.c
index 12354fc6f86d..58c27fd43bb4 100644
--- a/gcc/testsuite/gcc.target/bpf/core-attr-3.c
+++ b/gcc/testsuite/gcc.target/bpf/core-attr-3.c
@@ -11,14 +11,14 @@
struct O {
int e;
int f;
-};
+} __attribute__((preserve_access_index));
struct S {
int a;
struct {
int b;
int c;
- } inner;
+ } __attribute__((preserve_access_index)) inner;
struct O other;
} __attribute__((preserve_access_index));
diff --git a/gcc/testsuite/gcc.target/bpf/core-attr-4.c
b/gcc/testsuite/gcc.target/bpf/core-attr-4.c
index 6f025f42f3ee..c001b5b76ef9 100644
--- a/gcc/testsuite/gcc.target/bpf/core-attr-4.c
+++ b/gcc/testsuite/gcc.target/bpf/core-attr-4.c
@@ -13,8 +13,8 @@ struct T {
int d;
int e[4];
int f;
- } v;
- } u;
+ } __attribute__((preserve_access_index)) v;
+ } __attribute__((preserve_access_index)) u;
} __attribute__((preserve_access_index));
diff --git a/gcc/testsuite/gcc.target/bpf/core-attr-5.c
b/gcc/testsuite/gcc.target/bpf/core-attr-5.c
index 81e25fa85de7..4d443d88b0ae 100644
--- a/gcc/testsuite/gcc.target/bpf/core-attr-5.c
+++ b/gcc/testsuite/gcc.target/bpf/core-attr-5.c
@@ -11,7 +11,7 @@ struct U {
int e[4];
int f;
int *g;
- } v;
+ } __attribute__((preserve_access_index)) v;
} __attribute__((preserve_access_index));
struct T {
diff --git a/gcc/testsuite/gcc.target/bpf/core-attr-6.c
b/gcc/testsuite/gcc.target/bpf/core-attr-6.c
index 25215b5ae376..d43825ea97c3 100644
--- a/gcc/testsuite/gcc.target/bpf/core-attr-6.c
+++ b/gcc/testsuite/gcc.target/bpf/core-attr-6.c
@@ -11,8 +11,8 @@ struct U {
int e[4];
int f;
int *g;
- } v;
-} u;
+ } __attribute__((preserve_access_index)) v;
+} __attribute__((preserve_access_index)) u;
struct T {
int a;
diff --git a/gcc/testsuite/gcc.target/bpf/core-attr-7.c
b/gcc/testsuite/gcc.target/bpf/core-attr-7.c
new file mode 100644
index 000000000000..5ff8d9fcff95
--- /dev/null
+++ b/gcc/testsuite/gcc.target/bpf/core-attr-7.c
@@ -0,0 +1,150 @@
+/* Test for BPF CO-RE __attribute__((preserve_access_index)) with accesses on
+ LHS and both LHS and RHS of assignment. */
+
+/* { dg-do compile } */
+/* { dg-options "-O2 -dA -gbtf -mco-re -masm=normal" } */
+
+struct other
+{
+ char c;
+ int i;
+};
+
+struct inner_attr1
+{
+ int i1;
+ int i2;
+} __attribute__((preserve_access_index));
+
+struct inner_noattr
+{
+ int i1;
+ int i2;
+};
+
+union A_noattr
+{
+ struct inner_attr1 inner_attr;
+ struct inner_noattr inner_no_attr;
+ struct inner_noattr *inner_p;
+};
+union A_attr
+{
+ struct inner_attr1 inner_attr;
+ struct inner_noattr inner_no_attr;
+ struct inner_noattr *inner_p;
+} __attribute__((preserve_access_index));
+
+
+struct outer_noattr
+{
+ struct other *other;
+ struct inner_attr
+ {
+ int i1;
+ int i2;
+ } __attribute__((preserve_access_index)) inner;
+ struct inner_noattr inner_no_attr;
+ struct inner_attr1 *inner_p;
+ union A_attr a_attr;
+ union A_noattr a_noattr;
+};
+
+struct outer_attr
+{
+ struct other *other;
+ struct inner_attr
+ {
+ int i1;
+ int i2;
+ } __attribute__((preserve_access_index)) inner;
+
+ struct inner_noattr inner_no_attr;
+ struct inner_attr1 *inner_p;
+ union A_attr a_attr;
+ union A_noattr a_noattr;
+} __attribute__((preserve_access_index));
+
+extern void use_value(int);
+
+void
+func (struct outer_noattr *o, struct outer_attr *o_attr)
+{
+ /* 0:1 */
+ o->inner.i2 = 7;
+ /* 0:1 */
+ o->inner_p->i2 = 8;
+ /* nothing */
+ o->inner_no_attr.i2 = 9;
+
+ /* 0:2 */
+ o_attr->inner_no_attr.i2 = 10;
+
+ /* nothing */
+ o->a_noattr.inner_no_attr.i1 = 1;
+ /* 0:1 */
+ o->a_attr.inner_no_attr.i1 = 2;
+ /* 0:0 */
+ o->a_noattr.inner_attr.i1 = 3;
+ /* 0:4:0:0 */
+ o_attr->a_attr.inner_attr.i1 = 4;
+ /* 0:5 0:0 */
+ o_attr->a_noattr.inner_attr.i1 = 5;
+
+ /* This would still force everything as being attributed, although none of
+ the structs has the attribute. */
+ /* 0:5:2 0:0 */
+ __builtin_preserve_access_index (({ o->a_noattr.inner_p->i1 = 20; }));
+
+ /* 0:2 */
+ struct inner_noattr d = o_attr->inner_no_attr;
+ use_value(d.i2);
+}
+
+
+extern void use(void *);
+
+struct udphdr {
+ int source;
+ int dest;
+ int len;
+ int check;
+} __attribute__((preserve_access_index));
+
+union l4hdr {
+ struct udphdr udp;
+ int c;
+};
+
+struct v4hdr {
+ int a;
+ union l4hdr l4hdr;
+ int b;
+} __attribute__((packed));
+
+void gimple_loop_error(void)
+{
+ struct v4hdr h_outer;
+ h_outer.l4hdr.udp.source = 1024;
+ use(&h_outer.l4hdr.udp.source);
+}
+
+/* { dg-final { scan-assembler-times "ascii \"0:1.0\"\[\t
\]+\[^\n\]*btf_aux_string" 1 } } */
+/* { dg-final { scan-assembler-times "ascii \"0:0.0\"\[\t
\]+\[^\n\]*btf_aux_string" 1 } } */
+/* { dg-final { scan-assembler-times "ascii \"0:2.0\"\[\t
\]+\[^\n\]*btf_aux_string" 1 } } */
+/* { dg-final { scan-assembler-times "ascii \"0:5.0\"\[\t
\]+\[^\n\]*btf_aux_string" 1 } } */
+/* { dg-final { scan-assembler-times "ascii \"0:4:0:0.0\"\[\t
\]+\[^\n\]*btf_aux_string" 1 } } */
+/* { dg-final { scan-assembler-times "ascii \"0:5:2.0\"\[\t
\]+\[^\n\]*btf_aux_string" 1 } } */
+
+/* { dg-final { scan-assembler-times "bpfcr_astr_off \\(\"0:0\"\\)" 4 } } */
+/* { dg-final { scan-assembler-times "bpfcr_astr_off \\(\"0:1\"\\)" 3 } } */
+/* { dg-final { scan-assembler-times "bpfcr_astr_off \\(\"0:2\"\\)" 2 } } */
+/* { dg-final { scan-assembler-times "bpfcr_astr_off \\(\"0:5\"\\)" 1 } } */
+/* { dg-final { scan-assembler-times "bpfcr_astr_off \\(\"0:4:0:0\"\\)" 1 } }
*/
+/* { dg-final { scan-assembler-times "bpfcr_astr_off \\(\"0:5:2\"\\)" 1 } } */
+/* { dg-final { scan-assembler-times "bpfcr_type \\(struct inner_attr\\)" 1 }
} */
+/* { dg-final { scan-assembler-times "bpfcr_type \\(struct inner_attr1\\)" 3 }
} */
+/* { dg-final { scan-assembler-times "bpfcr_type \\(struct outer_attr\\)" 4 }
} */
+/* { dg-final { scan-assembler-times "bpfcr_type \\(union A_attr\\)" 1 } } */
+
+
diff --git a/gcc/testsuite/gcc.target/bpf/core-attr-calls.c
b/gcc/testsuite/gcc.target/bpf/core-attr-calls.c
index 87290c5c2116..27b08af1bb79 100644
--- a/gcc/testsuite/gcc.target/bpf/core-attr-calls.c
+++ b/gcc/testsuite/gcc.target/bpf/core-attr-calls.c
@@ -37,13 +37,13 @@ func (struct T *t, int i)
/* 0:3 */
get_other_u(t->ptr_u)->c = 43;
- /* 0:2:1 */
+ /* 0:2 */
get_other_v(&t->u.v)->d = 44;
}
/* { dg-final { scan-assembler-times "bpfcr_astr_off \\(\"0:3\"\\)" 2 } } */
/* { dg-final { scan-assembler-times "bpfcr_astr_off \\(\"0:0\"\\)" 1 } } */
-/* { dg-final { scan-assembler-times "bpfcr_astr_off \\(\"0:2:1\"\\)" 1 } } */
+/* { dg-final { scan-assembler-times "bpfcr_astr_off \\(\"0:2\"\\)" 1 } } */
/* { dg-final { scan-assembler-times "bpfcr_type \\(struct T\\)" 3 } } */
/* { dg-final { scan-assembler-times "bpfcr_type \\(struct U\\)" 1 } } */
--
2.47.3
