/*
* Parse and validate C declarations.
- * Copyright © 2011-2012, 2020-2021 Nick Bowler
+ * Copyright © 2011-2012, 2020-2021, 2023 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 "cdecl-internal.h"
#include "parse.h"
#include "scan.h"
+#include "errmsg.h"
+
+/*
+ * We can represent type specifiers as a bitmap, which gives us a finite
+ * list of acceptable bitmap values according to the C standard. However,
+ * the "long" specifier is allowed to occur more than once, but only at most
+ * 2 times. Treat it as a special case, assigning an unused bit to represent
+ * the second long.
+ */
+#define MAP_LLONG_BIT 31
+#define MAP_LONG_BIT (CDECL_TYPE_LONG-CDECL_SPEC_TYPE)
+#define CDECL_TYPE_LLONG (CDECL_SPEC_TYPE+MAP_LLONG_BIT)
+
+#include "typemap.h"
+
+/*
+ * Convert the declaration specifiers to a bitmap with each bit
+ * corresponding to one specific type specifier.
+ */
+static int valid_typespec(struct cdecl_declspec *s)
+{
+ unsigned long map = 0;
+
+ for (struct cdecl_declspec *c = s; c; c = c->next) {
+ unsigned long bit;
+
+ if (cdecl_spec_kind(c) != CDECL_SPEC_TYPE)
+ continue;
+
+ bit = c->type - CDECL_SPEC_TYPE;
+ assert(bit < MAP_LLONG_BIT);
+ bit = 1ul << bit;
+
+ /* "long" special case */
+ if ((map & bit) == 1ul << MAP_LONG_BIT)
+ bit = 1ul << MAP_LLONG_BIT;
+
+ if (map & bit) {
+ if (bit == 1ul << MAP_LLONG_BIT)
+ cdecl__errmsg(CDECL__ETOOLONG);
+ else
+ cdecl__errmsg(CDECL__EDUPTYPE);
+ return false;
+ }
+ map |= bit;
+ }
+
+ if (typemap_is_valid(map))
+ return true;
+
+ if (map == 0)
+ cdecl__errmsg(CDECL__ENOTYPE);
+ else
+ cdecl__errmsg(CDECL__EBADTYPE);
+
+ return false;
+}
/*
* Verify the declaration specifiers of a declaration. If top is true, treat
struct cdecl_declarator *d = decl->declarators;
bool abstract = cdecl_is_abstract(d);
unsigned num_storage = 0;
- unsigned long typemap;
- typemap = cdecl__build_typemap(specs);
- if (typemap == -1)
+ if (!valid_typespec(specs))
return false;
for (struct cdecl_declspec *c = specs; c; c = c->next) {
if (c->type == CDECL_TYPE_VOID &&
(d->type == CDECL_DECL_IDENT
|| d->type == CDECL_DECL_ARRAY)) {
- fprintf(stderr, "invalid declaration of type void\n");
+ cdecl__errmsg(CDECL__EBADVOID);
return false;
}
continue;
case CDECL_SPEC_STOR:
if (top && abstract) {
- fprintf(stderr, "type names cannot have storage-class specifiers\n");
+ cdecl__errmsg(CDECL__ETYPESTOR);
return false;
}
if (!top && c->type != CDECL_STOR_REGISTER) {
- fprintf(stderr, "function parameters may only have register storage\n");
+ cdecl__errmsg(CDECL__EFUNCSTOR);
return false;
}
if (++num_storage > 1) {
- fprintf(stderr, "too many storage-class specifiers\n");
+ cdecl__errmsg(CDECL__EMANYSTOR);
return false;
}
break;
* pointer qualifier list, which isn't checked here.
*/
if (c->type == CDECL_QUAL_RESTRICT) {
- fprintf(stderr, "only pointer types can be restrict-qualified.\n");
+ cdecl__errmsg(CDECL__EBADQUAL);
return false;
}
break;
case CDECL_SPEC_FUNC:
- if (abstract) {
- fprintf(stderr, "type names cannot have function specifiers\n");
+ if (abstract || !top || d->type != CDECL_DECL_FUNCTION) {
+ cdecl__errmsg(CDECL__ENOTFUNC);
return false;
}
- if (!top || d->type != CDECL_DECL_FUNCTION) {
- fprintf(stderr, "only function declarations may have function specifiers.\n");
- return false;
- }
break;
default:
assert(0);
free(d->child);
free(d);
- return 1;
+ return 0;
}
/*
}
if (d->child->type != CDECL_DECL_NULL) {
- fprintf(stderr, "invalid function parameter\n");
+ cdecl__errmsg(CDECL__EBADPARAM);
return -1;
}
if (decl->type == CDECL_DECL_FUNCTION
&& decl->child->type == CDECL_DECL_NULL
&& !function_is_reducible(decl)) {
- fprintf(stderr, "too many parentheses in function\n");
+ cdecl__errmsg(CDECL__EMANYPAREN);
return -1;
}
- return 1;
+ return 0;
}
return 0;
}
/*
- * Function parameters and return types have a few restrictions that are
- * really easy to check in comparison to the above absurdity.
+ * Returns nonzero iff the given specifier list contains a specifier
+ * of the indicated type.
*/
-static int
-check_parameters(struct cdecl_declarator **p, struct cdecl_declarator *d)
+static int have_specifier(struct cdecl_declspec *s, unsigned type)
{
- struct cdecl_declspec *spec;
- struct cdecl *param;
- bool has_void = false;
-
- if (d->type != CDECL_DECL_FUNCTION)
- return 0;
-
- for (param = d->u.function.parameters; param; param = param->next) {
- if (!valid_declspecs(param, false))
- return -1;
-
- /* Check for "void" function parameters as a special case. */
- for (spec = param->specifiers; spec; spec = spec->next) {
- if (param->declarators->type != CDECL_DECL_NULL)
- continue;
- if (spec->type != CDECL_TYPE_VOID)
- continue;
-
- if (spec != param->specifiers || spec->next != NULL) {
- fprintf(stderr, "void parameter must not have extra specifiers\n");
- return -1;
- } else if (d->u.function.parameters->next) {
- fprintf(stderr, "a void parameter must stand alone\n");
- return -1;
- } else if (d->u.function.variadic) {
- fprintf(stderr, "variadic functions cannot have a void parameter\n");
- return -1;
- }
- }
- }
-
+ for (; s; s = s->next)
+ if (s->type == type)
+ return 1;
return 0;
}
/*
- * Functions cannot return arrays or functions. Since the parse tree is
- * "inside-out", we need to look for functions as the child declarator.
+ * Check syntax restrictions on a function declarator's child declarator.
+ * That is, "pointer to function", "array of function" and "function
+ * returning function".
+ *
+ * Returns -1 if the declaration is invalid, or 0 otherwise.
*/
-static int
-check_rettypes(struct cdecl_declarator **p, struct cdecl_declarator *d)
+static int check_function_child(struct cdecl_declarator *d)
{
- if (!d->child || d->child->type != CDECL_DECL_FUNCTION)
- return 0;
+ struct cdecl_pointer *ptr;
switch (d->type) {
+ case CDECL_DECL_POINTER:
+ ptr = &d->u.pointer;
+ if (have_specifier(ptr->qualifiers, CDECL_QUAL_RESTRICT)) {
+ /* pointer to function cannot be restrict qualified. */
+ cdecl__errmsg(CDECL__ERESTRICTFUNC);
+ return -1;
+ }
+ return 0;
case CDECL_DECL_FUNCTION:
- fprintf(stderr, "functions cannot return functions\n");
+ /* function returning function is never allowed. */
+ cdecl__errmsg(CDECL__ERETFUNC);
return -1;
case CDECL_DECL_ARRAY:
- fprintf(stderr, "functions cannot return arrays\n");
+ /* array of function is never allowed. */
+ cdecl__errmsg(CDECL__EFUNCARRAY);
return -1;
}
return 0;
}
-static int
-check_arrays(struct cdecl_declarator **p, struct cdecl_declarator *d)
+/*
+ * Check a function parameter declaration for validity, which means it has a
+ * valid combination of declaration specifiers and, if it is a void parameter,
+ * that it is the one special case where this is allowed.
+ *
+ * Returns -1 if the declaration is invalid, or 0 otherwise.
+ */
+static int check_function_param(struct cdecl_function *f, struct cdecl *param)
{
- if (!d->child || d->child->type != CDECL_DECL_ARRAY)
- return 0;
-
- switch (d->type) {
- case CDECL_DECL_FUNCTION:
- fprintf(stderr, "array members cannot be functions\n");
+ if (!valid_declspecs(param, false))
return -1;
+
+ /* Check for "void" function parameters as a special case. */
+ if (param->declarators->type == CDECL_DECL_NULL
+ && have_specifier(param->specifiers, CDECL_TYPE_VOID))
+ {
+ struct cdecl *fp = f->parameters;
+
+ if (f->variadic || fp->next || fp->specifiers->next) {
+ cdecl__errmsg(CDECL__EVOIDPARAM);
+ return -1;
+ }
}
return 0;
}
-static int
-normalize_specs(struct cdecl_declarator **p, struct cdecl_declarator *d)
+/*
+ * Normalize the specifier lists for function parameters, and then check the
+ * function declarator for validity.
+ *
+ * Returns -1 if the declaration is invalid, or 0 otherwise.
+ */
+static int postproc_function(struct cdecl_declarator *d)
{
- struct cdecl_function *func;
- struct cdecl_pointer *ptr;
+ struct cdecl_function *func = &d->u.function;
+ struct cdecl *param;
+ int rc;
- switch (d->type) {
- case CDECL_DECL_POINTER:
- ptr = &d->u.pointer;
- ptr->qualifiers = cdecl__normalize_specs(ptr->qualifiers);
- break;
- case CDECL_DECL_FUNCTION:
- func = &d->u.function;
- for (struct cdecl *i = func->parameters; i; i = i->next)
- i->specifiers = cdecl__normalize_specs(i->specifiers);
- break;
+ for (param = func->parameters; param; param = param->next) {
+ param->specifiers = cdecl__normalize_specs(param->specifiers);
+
+ if ((rc = check_function_param(func, param)) < 0)
+ return rc;
}
- return 0;
+ return check_function_child(d->child);
}
static int
-check_qualifiers(struct cdecl_declarator **p, struct cdecl_declarator *d)
+postproc_common(struct cdecl_declarator **p, struct cdecl_declarator *d)
{
- struct cdecl_declspec *spec;
struct cdecl_pointer *ptr;
- if (!d->child || d->child->type != CDECL_DECL_POINTER)
+ switch (d->type) {
+ case CDECL_DECL_POINTER:
+ ptr = &d->u.pointer;
+ ptr->qualifiers = cdecl__normalize_specs(ptr->qualifiers);
return 0;
-
- ptr = &d->child->u.pointer;
- for (spec = ptr->qualifiers; spec; spec = spec->next) {
- if (spec->type == CDECL_QUAL_RESTRICT
- && d->type == CDECL_DECL_FUNCTION) {
- fprintf(stderr, "function pointers cannot be restrict-qualified\n");
+ case CDECL_DECL_FUNCTION:
+ return postproc_function(d);
+ case CDECL_DECL_ARRAY:
+ if (d->child && d->child->type == CDECL_DECL_FUNCTION) {
+ /* function returning array is never allowed. */
+ cdecl__errmsg(CDECL__ERETARRAY);
return -1;
}
+ return 0;
}
return 0;
* depth-first preorder traversal. The function is given a pointer to the
* declarator as well as to the pointer which was used to reach that
* declarator: this can be used to rewrite entire subtrees.
+ *
+ * The called function may return a negative value to indicate an error
+ * which terminates traversal.
+ *
+ * Returns 0 on success, or a negative value on failure.
*/
-static bool forall_declarators(struct cdecl *decl,
+static int forall_declarators(struct cdecl *decl,
int f(struct cdecl_declarator **, struct cdecl_declarator *))
{
struct cdecl_declarator *d, **p;
- for (p = &decl->declarators, d = *p; d; p = &d->child, d = *p) {
- switch (f(p, d)) {
- case 0:
- break;
- case 1:
- d = *p;
- break;
- case -1:
- return false;
- default:
- assert(0);
- }
+ for (p = &decl->declarators; *p; p = &d->child) {
+ int rc;
+
+ rc = f(p, *p);
+ if (rc < 0)
+ return rc;
+ d = *p;
if (d->type == CDECL_DECL_FUNCTION) {
struct cdecl *i;
for (i = d->u.function.parameters; i; i = i->next) {
- if (!forall_declarators(i, f))
- return false;
+ rc = forall_declarators(i, f);
+ if (rc < 0)
+ return rc;
}
}
}
- return true;
+ return 0;
}
-struct cdecl *cdecl_parse_decl(const char *declstr)
+static struct cdecl *do_parse(const char *str, int english_mode)
{
- struct cdecl_declspec *norm_specs;
YY_BUFFER_STATE state;
yyscan_t scanner;
struct cdecl *decl;
- int rc;
- cdecl__init_i18n();
+#if YYDEBUG
+ extern int cdecl__yydebug;
+ cdecl__yydebug = 1;
+#endif
- rc = cdecl__yylex_init(&scanner);
- if (rc != 0)
+ cdecl__init_i18n();
+ if (cdecl__yylex_init_extra(english_mode, &scanner) != 0)
return NULL;
- state = cdecl__yy_scan_string(declstr, scanner);
- rc = cdecl__yyparse(scanner, &decl);
+ state = cdecl__yy_scan_string(str, scanner);
+ if (cdecl__yyparse(scanner, &decl) != 0)
+ decl = NULL;
cdecl__yy_delete_buffer(state, scanner);
cdecl__yylex_destroy(scanner);
- if (rc != 0)
- return NULL;
+ return decl;
+}
+
+static int do_postprocess(struct cdecl *decl, int english_mode)
+{
+ struct cdecl_declspec *norm_specs;
+ struct cdecl *i;
/*
- * Since the top-level specifiers are shared between each top-level
- * declarator, we need to normalize them once and then propagate the
- * new specifier list.
+ * For a C declaration with more than one full declarator, the
+ * specifier list is common to all of them. Normalize it once,
+ * then propagate that to all the linked cdecl structures.
+ *
+ * In english mode, the cdecl structure list always has exactly
+ * one entry so we don't need to do anything differently.
*/
norm_specs = cdecl__normalize_specs(decl->specifiers);
- for (struct cdecl *i = decl; i; i = i->next) {
+ for (i = decl; i; i = i->next)
i->specifiers = norm_specs;
- }
- /* Now perform checks and simplifications on each declarator. */
- for (struct cdecl *i = decl; i; i = i->next) {
- if (!forall_declarators(i, reduce_parentheses))
- goto err;
- if (!forall_declarators(i, simplify_functions))
- goto err;
- if (!forall_declarators(i, check_parameters))
- goto err;
- if (!forall_declarators(i, check_rettypes))
- goto err;
- if (!forall_declarators(i, check_arrays))
- goto err;
- if (!forall_declarators(i, normalize_specs))
- goto err;
- if (!forall_declarators(i, check_qualifiers))
- goto err;
+ for (i = decl; i; i = i->next) {
+ if (!english_mode) {
+ if (forall_declarators(i, reduce_parentheses) < 0)
+ return 0;
+ if (forall_declarators(i, simplify_functions) < 0)
+ return 0;
+ }
+
+ if (forall_declarators(i, postproc_common) < 0)
+ return 0;
if (!valid_declspecs(i, true))
- goto err;
+ return 0;
if (cdecl_is_abstract(i->declarators)
&& (i != decl || i->next)) {
- fprintf(stderr, "mixing type names and declarations is not allowed\n");
- goto err;
+ cdecl__errmsg(CDECL__EDECLTYPE);
+ return 0;
}
}
- return decl;
-err:
- cdecl__free(decl);
- return NULL;
+ return 1;
}
-struct cdecl *cdecl_parse_english(const char *english)
+static struct cdecl *parse_common(const char *str, int english_mode)
{
- YY_BUFFER_STATE state;
- yyscan_t scanner;
struct cdecl *decl;
- int rc;
-
- cdecl__init_i18n();
- rc = cdecl__yylex_init_extra(true, &scanner);
- if (rc != 0)
+ if (!(decl = do_parse(str, english_mode)))
return NULL;
- state = cdecl__yy_scan_string(english, scanner);
- rc = cdecl__yyparse(scanner, &decl);
- cdecl__yy_delete_buffer(state, scanner);
- cdecl__yylex_destroy(scanner);
-
- if (rc != 0)
+ if (!do_postprocess(decl, english_mode)) {
+ cdecl__free(decl);
return NULL;
-
- for (struct cdecl *i = decl; i; i = i->next) {
- i->specifiers = cdecl__normalize_specs(i->specifiers);
-
- if (!forall_declarators(i, check_parameters))
- goto err;
- if (!forall_declarators(i, check_rettypes))
- goto err;
- if (!forall_declarators(i, check_arrays))
- goto err;
- if (!forall_declarators(i, normalize_specs))
- goto err;
- if (!forall_declarators(i, check_qualifiers))
- goto err;
-
- if (!valid_declspecs(i, true))
- goto err;
}
return decl;
-err:
- cdecl__free(decl);
- return NULL;
+}
+
+struct cdecl *cdecl_parse_decl(const char *declstr)
+{
+ return parse_common(declstr, false);
+}
+
+struct cdecl *cdecl_parse_english(const char *english)
+{
+ return parse_common(english, true);
}
void cdecl_free(struct cdecl *decl)