/*
* Parse and validate C declarations.
- * Copyright © 2011-2012, 2020-2021, 2023 Nick Bowler
+ * Copyright © 2011-2012, 2020-2021, 2023-2024 Nick Bowler
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
#include "scan.h"
#include "errmsg.h"
+static struct cdecl *fake_function_param(struct cdecl_declarator *);
+
/*
* Allocate a "parse item", which is a union of several parse tree
* structure types, together with a string buffer. The s_sz argument
*/
static int valid_typespec(struct cdecl_declspec *s)
{
+ struct cdecl_declspec *c;
unsigned long map = 0;
- for (struct cdecl_declspec *c = s; c; c = c->next) {
+ for (c = s; c; c = c->next) {
unsigned long bit;
if (cdecl_spec_kind(c) != CDECL_SPEC_TYPE)
*/
static bool valid_declspecs(struct cdecl *decl, bool top)
{
- struct cdecl_declspec *specs = decl->specifiers;
+ struct cdecl_declspec *c, *specs = decl->specifiers;
struct cdecl_declarator *d = decl->declarators;
bool abstract = cdecl_is_abstract(d);
unsigned num_storage = 0;
if (!valid_typespec(specs))
return false;
- for (struct cdecl_declspec *c = specs; c; c = c->next) {
+ for (c = specs; c; c = c->next) {
switch (cdecl_spec_kind(c)) {
case CDECL_SPEC_TYPE:
if (c->type == CDECL_TYPE_VOID &&
return true;
}
+/*
+ * Find the tree pointer which leads to the parameter's leaf node.
+ *
+ * Return a null pointer if the traversal locates a syntactic element which
+ * prevents function reduction. This occurs if the leaf node declares an
+ * identifier, or for nontrivial fake function parameters (see below).
+ */
+static struct cdecl_declarator **leaf_pointer(struct cdecl *param)
+{
+ struct cdecl_declarator *d, **p = ¶m->declarators;
+
+ if ((param = fake_function_param(param->declarators))) {
+ if (param->declarators->type != CDECL_DECL_NULL)
+ return NULL; /* e.g. int (x (*)) */
+ }
+
+ while ((d = *p)->child) {
+ p = &d->child;
+
+ if (fake_function_param(d->child))
+ return NULL; /* e.g. int (x (*)[][1]) */
+ }
+
+ if (d->type != CDECL_DECL_NULL)
+ return NULL; /* e.g. int (x y) */
+
+ return p;
+}
+
+
/*
* The C grammar leaves ambiguous some cases where parentheses represent a
* function declarator or just parentheses. The language uses additional
static struct cdecl_declarator *reduce_function(struct cdecl *param)
{
- struct cdecl_declarator *d, **p = ¶m->declarators;
struct parse_item *spec = (void *)param->specifiers;
+ struct cdecl_declarator *d, **p;
- while ((d = *p)->child)
- p = &d->child;
-
- if (d->type != CDECL_DECL_NULL)
+ if (!(p = leaf_pointer(param)))
return NULL;
/*
spec->u.declarator.type = CDECL_DECL_IDENT;
*p = &spec->u.declarator;
- free(d);
d = param->declarators;
free(param);
return d;
new = reduce_function(d->u.function.parameters);
if (!new)
- return 0; /* e.g. int (foo bar) */
+ return 0;
*p = new;
- free(d->child);
free(d);
return 1;
static struct cdecl *do_parse(const char *str, int english_mode)
{
+ struct cdecl *decl = NULL;
YY_BUFFER_STATE state;
yyscan_t scanner;
- struct cdecl *decl;
#if YYDEBUG
extern int cdecl__yydebug;
return NULL;
state = cdecl__yy_scan_string(str, scanner);
- if (cdecl__yyparse(scanner, &decl) != 0)
+ if (cdecl__yyparse(scanner, &decl) != 0) {
+ /*
+ * If the input consists of a complete, valid declaration
+ * followed by some garbage, that parsed declaration will
+ * be output by the parser and we need to free it here.
+ */
+ cdecl__free(decl);
decl = NULL;
+ }
cdecl__yy_delete_buffer(state, scanner);
cdecl__yylex_destroy(scanner);