Hi David, everyone,
Following Davids last review I decided to properly detect error cases,
as suggested.
The error however should be reported earlier in compilation in
pack_enum_valud function, where all the errors are reported.
Thanks for the quick and detailed reviews.
Regards,
Cupertino
The BPF backend was allocating an unnecessarily large string when
constructing CO-RE relocations for enum types.
This patch further verifies if an enumerator is valid for CO-RE
representability and returns an error in those cases.
gcc/ChangeLog:
* config/bpf/core-builtins.cc (get_index_for_enum_value): Create
function.
(pack_enum_value): Check for enumerator and error out.
(process_enum_value): Correct string allocation.
---
gcc/config/bpf/core-builtins.cc | 57 ++++++++++++++++++++++-----------
1 file changed, 38 insertions(+), 19 deletions(-)
diff --git a/gcc/config/bpf/core-builtins.cc b/gcc/config/bpf/core-builtins.cc
index e03e986e2c1..829acea98f7 100644
--- a/gcc/config/bpf/core-builtins.cc
+++ b/gcc/config/bpf/core-builtins.cc
@@ -795,6 +795,23 @@ process_field_expr (struct cr_builtins *data)
static GTY(()) hash_map<tree, tree> *bpf_enum_mappings;
tree enum_value_type = NULL_TREE;
+static int
+get_index_for_enum_value (tree type, tree expr)
+{
+ gcc_assert (TREE_CODE (expr) == CONST_DECL
+ && TREE_CODE (type) == ENUMERAL_TYPE);
+
+ unsigned int index = 0;
+ for (tree l = TYPE_VALUES (type); l; l = TREE_CHAIN (l))
+ {
+ gcc_assert (index < (1 << 16));
+ if (TREE_VALUE (l) == expr)
+ return index;
+ index++;
+ }
+ return -1;
+}
+
/* Pack helper for the __builtin_preserve_enum_value. */
static struct cr_local
@@ -846,6 +863,16 @@ pack_enum_value_fail:
ret.reloc_data.default_value = integer_one_node;
}
+ if (ret.fail == false )
+ {
+ int index = get_index_for_enum_value (type, tmp);
+ if (index == -1 || index >= (1 << 16))
+ {
+ bpf_error ("enum value in CO-RE builtin cannot be represented");
+ ret.fail = true;
+ }
+ }
+
ret.reloc_data.type = type;
ret.reloc_data.kind = kind;
return ret;
@@ -864,25 +891,17 @@ process_enum_value (struct cr_builtins *data)
struct cr_final ret = { NULL, type, data->kind };
- if (TREE_CODE (expr) == CONST_DECL
- && TREE_CODE (type) == ENUMERAL_TYPE)
- {
- unsigned int index = 0;
- for (tree l = TYPE_VALUES (type); l; l = TREE_CHAIN (l))
- {
- if (TREE_VALUE (l) == expr)
- {
- char *tmp = (char *) ggc_alloc_atomic ((index / 10) + 1);
- sprintf (tmp, "%d", index);
- ret.str = (const char *) tmp;
-
- break;
- }
- index++;
- }
- }
- else
- gcc_unreachable ();
+ gcc_assert (TREE_CODE (expr) == CONST_DECL
+ && TREE_CODE (type) == ENUMERAL_TYPE);
+
+ int index = get_index_for_enum_value (type, expr);
+ gcc_assert (index != -1 && index < (1 << 16));
+
+ /* Index can only be a value up to 2^16. Should always fit
+ in 6 chars. */
+ char tmp[6];
+ sprintf (tmp, "%u", index);
+ ret.str = CONST_CAST (char *, ggc_strdup(tmp));
return ret;
}
--
2.30.2
