Hi all,
This is the beginning of a patch to introduce the extended attribute
for asm declarations proposed in
https://gcc.gnu.org/pipermail/gcc-patches/2023-November/636563.html. I
will need some reviewer help in implementing this patch, as I am not
very familiar with gcc's internals.
The attribute in question looks as such (Example):
[[gnu::extended([output] "=r" (output) [otheroutput] "=r" (otheroutput),
[input] "r" (input) [otherinput] "r" (otherinput),
"%rcx" "%rdx", label, volatile stack)]]
asm ("");
I would really appreciate any reviews, as well as help in implementing
this patch
best regards,
Julian
From a189f2820025315b5574d0e9384b96301c6ba7e8 Mon Sep 17 00:00:00 2001
From: TheShermanTanker <tanksherman27@gmail.com>
Date: Fri, 17 Nov 2023 11:09:50 +0800
Subject: [PATCH] Introduce the extended attribute for asm declarations
---
gcc/cp/parser.cc | 25 +++++++++++++++++++++++++
gcc/cp/tree.cc | 11 +++++++++++
2 files changed, 36 insertions(+)
diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
index 5116bcb78f6..ecc5f2fabc1 100644
--- a/gcc/cp/parser.cc
+++ b/gcc/cp/parser.cc
@@ -15407,6 +15407,13 @@ cp_parser_block_declaration (cp_parser *parser,
cp_parser_commit_to_tentative_parse (parser);
cp_parser_asm_definition (parser);
}
+ else if ((attr_idx = cp_parser_skip_std_attribute_spec_seq (parser, 1)) != 1
+ && cp_lexer_nth_token_is_keyword (parser->lexer, attr_idx, RID_ASM))
+ {
+ if (statement_p)
+ cp_parser_commit_to_tentative_parse (parser);
+ cp_parser_asm_definition (parser);
+ }
/* If the next keyword is `namespace', we have a
namespace-alias-definition. */
else if (token1->keyword == RID_NAMESPACE)
@@ -22397,6 +22404,23 @@ cp_parser_asm_definition (cp_parser* parser)
bool invalid_inputs_p = false;
bool invalid_outputs_p = false;
required_token missing = RT_NONE;
+
+ tree attrs = cp_parser_std_attribute_spec_seq (parser);
+ tree extended = error_mark_node;
+
+ if (cp_lexer_next_token_is (parser->lexer, CPP_SEMICOLON))
+ {
+ /* Error during attribute parsing that resulted in skipping
+ to next semicolon. */
+ cp_parser_require (parser, CPP_SEMICOLON, RT_SEMICOLON);
+ return;
+ }
+
+ if (attrs != error_mark_node)
+ {
+ extended = lookup_attribute ("gnu", "extended", attrs);
+ }
+
location_t asm_loc = cp_lexer_peek_token (parser->lexer)->location;
/* Look for the `asm' keyword. */
@@ -22511,6 +22535,7 @@ cp_parser_asm_definition (cp_parser* parser)
two `:' tokens. */
if (cp_parser_allow_gnu_extensions_p (parser)
&& parser->in_function_body
+ && extended == error_mark_node
&& (cp_lexer_next_token_is (parser->lexer, CPP_COLON)
|| cp_lexer_next_token_is (parser->lexer, CPP_SCOPE)))
{
diff --git a/gcc/cp/tree.cc b/gcc/cp/tree.cc
index 417c92ba76f..1f081b3dfd8 100644
--- a/gcc/cp/tree.cc
+++ b/gcc/cp/tree.cc
@@ -46,6 +46,7 @@ static tree verify_stmt_tree_r (tree *, int *, void *);
static tree handle_init_priority_attribute (tree *, tree, tree, int, bool *);
static tree handle_abi_tag_attribute (tree *, tree, tree, int, bool *);
+static tree handle_extended_attribute (tree *, tree, tree, int, bool *);
static tree handle_contract_attribute (tree *, tree, tree, int, bool *);
/* If REF is an lvalue, returns the kind of lvalue that REF is.
@@ -5080,6 +5081,8 @@ const struct attribute_spec cxx_attribute_table[] =
handle_init_priority_attribute, NULL },
{ "abi_tag", 1, -1, false, false, false, true,
handle_abi_tag_attribute, NULL },
+ { "extended", 0, 5, true, false, false, false,
+ handle_extended_attribute, NULL },
{ NULL, 0, 0, false, false, false, false, NULL, NULL }
};
@@ -5350,6 +5353,14 @@ handle_abi_tag_attribute (tree* node, tree name, tree args,
return NULL_TREE;
}
+static tree
+handle_extended_attribute (tree *node, tree name, tree args, int flags, bool *no_add_attrs)
+{
+ /* TODO What could be done here? */
+ *no_add_attrs = true;
+ return NULL_TREE;
+}
+
/* Perform checking for contract attributes. */
tree
--
2.41.0
