From: David Faust <david.faust@oracle.com>
To: gcc-patches@gcc.gnu.org
Cc: jose.marchesi@oracle.com
Subject: [PATCH] bpf: Use enum for resolved overloaded builtins
Date: Mon, 7 Nov 2022 14:48:29 -0800 [thread overview]
Message-ID: <20221107224829.12440-1-david.faust@oracle.com> (raw)
Change several places in the eBPF backend dealing with overloaded
built-in functions to consistently use the enum bpf_builtins type,
rather than variously using integer constants or booleans. The result is
eaiser to read and extend.
Tested on bpf-unknown-none, no known regressions.
OK to push?
Thanks.
gcc/
* config/bpf/bpf.cc (struct core_walk_data): Add field `which'...
(bpf_resolve_overloaded_builtin): ... set it here. Use values of enum
bpf_builtins for error checks.
(bpf_core_walk): Use values of enum bpf_builtins.
(bpf_core_newdecl): Likewise.
(bpf_expand_builtin): Likewise.
---
gcc/config/bpf/bpf.cc | 106 +++++++++++++++++++++++-------------------
1 file changed, 59 insertions(+), 47 deletions(-)
diff --git a/gcc/config/bpf/bpf.cc b/gcc/config/bpf/bpf.cc
index fd4003c2bfc..16af2412bf6 100644
--- a/gcc/config/bpf/bpf.cc
+++ b/gcc/config/bpf/bpf.cc
@@ -1222,7 +1222,7 @@ bpf_expand_builtin (tree exp, rtx target ATTRIBUTE_UNUSED,
return gen_rtx_REG (ops[0].mode, BPF_R0);
}
- else if (code == -1)
+ else if (code == -BPF_BUILTIN_PRESERVE_ACCESS_INDEX)
{
/* A resolved overloaded __builtin_preserve_access_index. */
tree arg = CALL_EXPR_ARG (exp, 0);
@@ -1249,7 +1249,7 @@ bpf_expand_builtin (tree exp, rtx target ATTRIBUTE_UNUSED,
return expand_normal (arg);
}
- else if (code == -2)
+ else if (code == -BPF_BUILTIN_PRESERVE_FIELD_INFO)
{
/* A resolved overloaded __builtin_preserve_field_info. */
tree src = CALL_EXPR_ARG (exp, 0);
@@ -1444,28 +1444,37 @@ bpf_core_get_index (const tree node)
__builtin_preserve_access_index. */
static tree
-bpf_core_newdecl (tree type, bool is_pai)
+bpf_core_newdecl (tree type, enum bpf_builtins which)
{
tree rettype;
char name[80];
static unsigned long pai_count = 0;
static unsigned long pfi_count = 0;
- if (is_pai)
+ switch (which)
{
- rettype = build_function_type_list (type, type, NULL);
- int len = snprintf (name, sizeof (name), "%s", "__builtin_pai_");
- len = snprintf (name + len, sizeof (name) - len, "%lu", pai_count++);
- }
- else
- {
- rettype = build_function_type_list (unsigned_type_node, type,
- unsigned_type_node, NULL);
- int len = snprintf (name, sizeof (name), "%s", "__builtin_pfi_");
- len = snprintf (name + len, sizeof (name) - len, "%lu", pfi_count++);
+ case BPF_BUILTIN_PRESERVE_ACCESS_INDEX:
+ {
+ rettype = build_function_type_list (type, type, NULL);
+ int len = snprintf (name, sizeof (name), "%s", "__builtin_pai_");
+ len = snprintf (name + len, sizeof (name) - len, "%lu", pai_count++);
+ }
+ break;
+
+ case BPF_BUILTIN_PRESERVE_FIELD_INFO:
+ {
+ rettype = build_function_type_list (unsigned_type_node, type,
+ unsigned_type_node, NULL);
+ int len = snprintf (name, sizeof (name), "%s", "__builtin_pfi_");
+ len = snprintf (name + len, sizeof (name) - len, "%lu", pfi_count++);
+ }
+ break;
+
+ default:
+ gcc_unreachable ();
}
- return add_builtin_function_ext_scope (name, rettype, is_pai ? -1 : -2,
+ return add_builtin_function_ext_scope (name, rettype, -which,
BUILT_IN_MD, NULL, NULL_TREE);
}
@@ -1492,6 +1501,7 @@ bpf_core_is_maybe_aggregate_access (tree expr)
struct core_walk_data {
location_t loc;
+ enum bpf_builtins which;
tree arg;
};
@@ -1501,7 +1511,6 @@ static tree
bpf_core_walk (tree *tp, int *walk_subtrees, void *data)
{
struct core_walk_data *dat = (struct core_walk_data *) data;
- bool is_pai = dat->arg == NULL_TREE;
/* If this is a type, don't do anything. */
if (TYPE_P (*tp))
@@ -1510,19 +1519,21 @@ bpf_core_walk (tree *tp, int *walk_subtrees, void *data)
return NULL_TREE;
}
- /* Build a new function call to a resolved builtin for the desired operation.
- If this is a preserve_field_info call, pass along the argument to the
- resolved builtin call. */
- if (bpf_core_is_maybe_aggregate_access (*tp))
- {
- tree newdecl = bpf_core_newdecl (TREE_TYPE (*tp), is_pai);
- tree newcall;
- if (is_pai)
- newcall = build_call_expr_loc (dat->loc, newdecl, 1, *tp);
- else
- newcall = build_call_expr_loc (dat->loc, newdecl, 2, *tp, dat->arg);
+ /* Build a new function call to a type-resolved temporary builtin for the
+ desired operation, and pass along args as necessary. */
+ tree newdecl = bpf_core_newdecl (TREE_TYPE (*tp), dat->which);
- *tp = newcall;
+ if (dat->which == BPF_BUILTIN_PRESERVE_ACCESS_INDEX)
+ {
+ if (bpf_core_is_maybe_aggregate_access (*tp))
+ {
+ *tp = build_call_expr_loc (dat->loc, newdecl, 1, *tp);
+ *walk_subtrees = 0;
+ }
+ }
+ else
+ {
+ *tp = build_call_expr_loc (dat->loc, newdecl, 2, *tp, dat->arg);
*walk_subtrees = 0;
}
@@ -1572,32 +1583,26 @@ bpf_is_valid_preserve_field_info_arg (tree expr)
/* Implement TARGET_RESOLVE_OVERLOADED_BUILTIN (see gccint manual section
Target Macros::Misc.).
- We use this for the __builtin_preserve_access_index builtin for CO-RE
- support.
+ Used for CO-RE support builtins such as __builtin_preserve_access_index
+ and __builtin_preserve_field_info.
FNDECL is the declaration of the builtin, and ARGLIST is the list of
- arguments passed to it, and is really a vec<tree,_> *.
-
- In this case, the 'operation' implemented by the builtin is a no-op;
- the builtin is just a marker. So, the result is simply the argument. */
+ arguments passed to it, and is really a vec<tree,_> *. */
static tree
bpf_resolve_overloaded_builtin (location_t loc, tree fndecl, void *arglist)
{
- bool is_pai = DECL_MD_FUNCTION_CODE (fndecl)
- == BPF_BUILTIN_PRESERVE_ACCESS_INDEX;
- bool is_pfi = DECL_MD_FUNCTION_CODE (fndecl)
- == BPF_BUILTIN_PRESERVE_FIELD_INFO;
+ enum bpf_builtins which = (enum bpf_builtins) DECL_MD_FUNCTION_CODE (fndecl);
- if (!is_pai && !is_pfi)
+ if (which < BPF_BUILTIN_PRESERVE_ACCESS_INDEX
+ || which >= BPF_BUILTIN_MAX)
return NULL_TREE;
- /* We only expect one argument, but it may be an arbitrarily-complicated
- statement-expression. */
vec<tree, va_gc> *params = static_cast<vec<tree, va_gc> *> (arglist);
unsigned n_params = params ? params->length() : 0;
- if ((is_pai && n_params != 1) || (is_pfi && n_params != 2))
+ if (!(which == BPF_BUILTIN_PRESERVE_ACCESS_INDEX && n_params == 1)
+ && n_params != 2)
{
error_at (loc, "wrong number of arguments");
return error_mark_node;
@@ -1605,12 +1610,15 @@ bpf_resolve_overloaded_builtin (location_t loc, tree fndecl, void *arglist)
tree param = (*params)[0];
- /* If not generating BPF_CORE information, preserve_access_index does nothing,
- and simply "resolves to" the argument. */
- if (!TARGET_BPF_CORE && is_pai)
+ /* If not generating BPF_CORE information, preserve_access_index does
+ nothing, and simply "resolves to" the argument. */
+ if (which == BPF_BUILTIN_PRESERVE_ACCESS_INDEX && !TARGET_BPF_CORE)
return param;
- if (is_pfi && !bpf_is_valid_preserve_field_info_arg (param))
+ /* For __builtin_preserve_field_info, enforce that the parameter is exactly a
+ field access and not a more complex expression. */
+ else if (which == BPF_BUILTIN_PRESERVE_FIELD_INFO
+ && !bpf_is_valid_preserve_field_info_arg (param))
{
error_at (EXPR_LOC_OR_LOC (param, loc),
"argument is not a field access");
@@ -1642,7 +1650,11 @@ bpf_resolve_overloaded_builtin (location_t loc, tree fndecl, void *arglist)
struct core_walk_data data;
data.loc = loc;
- data.arg = is_pai ? NULL_TREE : (*params)[1];
+ data.which = which;
+ if (which == BPF_BUILTIN_PRESERVE_ACCESS_INDEX)
+ data.arg = NULL_TREE;
+ else
+ data.arg = (*params)[1];
walk_tree (¶m, bpf_core_walk, (void *) &data, NULL);
--
2.37.2
next reply other threads:[~2022-11-07 22:49 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-07 22:48 David Faust [this message]
2022-11-08 8:02 ` Jose E. Marchesi
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