%code top {
/*
* Parser for C declarations.
- * Copyright © 2011-2012, 2021, 2023 Nick Bowler
+ * Copyright © 2011-2012, 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 <stdbool.h>
#include "scan.h"
-#include "cdecl.h"
#include "cdecl-internal.h"
#include "errmsg.h"
-#define FAIL(msg) do { \
- yyerror(&yylloc, NULL, NULL, msg); \
- YYERROR; \
+/*
+ * Allocate a parse tree node via cdecl__alloc_item.
+ *
+ * - m1 specifies the item's union member to assign to ptr, which selects the
+ * type of node to allocate.
+ *
+ * - m2 specifies the "next" or "child" member, which is initialized to a null
+ * pointer. The cdecl__alloc_item function sets the declarator.child member
+ * to null; we explicitly copy this null pointer to the returned union member
+ * to avoid type punning. It is hoped that compilers will notice that these
+ * pointers are at the same offset therefore the assignment can be elided.
+ *
+ * The resulting pointer can be passed directly to free, as the union is the
+ * first member of the parse_item structure.
+ *
+ * Use the wrapper macros below instead of this one.
+ */
+#define ALLOC_ITEM(ptr, m1, m2) do { \
+ struct parse_item *item; \
+ if (!(item = cdecl__alloc_item(0))) \
+ YYERROR; \
+ item->u.m1.m2 = (void *)item->u.declarator.child; \
+ (ptr) = &item->u.m1; \
} while (0)
-#define ALLOC(ptr, size) do { \
- (ptr) = malloc(size); \
- if (!(ptr)) { \
- cdecl__errmsg(CDECL__ENOMEM); \
- YYERROR; \
- } \
+/* Wrappers for ALLOC_ITEM to allocate various kinds of parser structures. */
+#define ALLOC_ITEM_DECLARATOR(ptr) ALLOC_ITEM(ptr, declarator, child)
+#define ALLOC_ITEM_DECLSPEC(ptr) ALLOC_ITEM(ptr, declspec, next)
+#define ALLOC_ITEM_DECL(ptr) ALLOC_ITEM(ptr, decl, next)
+
+#define ALLOC_FUNCTION_(ptr, parameters_) do { \
+ ALLOC_ITEM_DECLARATOR(ptr); \
+ (ptr)->type = CDECL_DECL_FUNCTION; \
+ (ptr)->u.function.parameters = parameters_; \
+} while (0)
+
+#define ALLOC_FUNCTION(ptr, parameters_, variadic_) do { \
+ ALLOC_FUNCTION_(ptr, parameters_); \
+ (ptr)->u.function.variadic = variadic_; \
+} while (0)
+
+#define ALLOC_ARRAY(ptr, length_) do { \
+ ALLOC_ITEM_DECLARATOR(ptr); \
+ (ptr)->type = CDECL_DECL_ARRAY; \
+ (ptr)->u.array.vla = NULL; \
+ (ptr)->u.array.length = length_; \
} while (0)
-#define ALLOC_STRUCT(ptr, type, ...) do { \
- ALLOC(ptr, sizeof (type)); \
- *(ptr) = (type) { __VA_ARGS__ }; \
+#define ALLOC_POINTER(ptr, qualifiers_, child_) do { \
+ ALLOC_ITEM_DECLARATOR(ptr); \
+ (ptr)->child = child_; \
+ (ptr)->type = CDECL_DECL_POINTER; \
+ (ptr)->u.pointer.qualifiers = qualifiers_; \
+} while (0)
+
+#define ALLOC_DECLSPEC(ptr, type_) do { \
+ ALLOC_ITEM_DECLSPEC(ptr); \
+ (ptr)->type = type_; \
+ (ptr)->ident = NULL; \
+} while (0)
+
+#define ALLOC_DECL(ptr, specifiers_, declarators_) do { \
+ ALLOC_ITEM_DECL(ptr); \
+ (ptr)->specifiers = specifiers_; \
+ (ptr)->declarators = declarators_; \
} while (0)
/*
* name strings can be used directly in error messages and there is no
* need for any string processing.
*/
-#define yytnamerr(a, b) cdecl__strlcpy(a, b, (a) ? INT_MAX : 0)
+#define yytnamerr(a, b) ( (a) ? cdecl__strlcpy(a, b, -1) : strlen(b) )
%}
%code requires {
#include <inttypes.h>
+#include <stdbool.h>
+#include "cdecl.h"
}
%code provides {
}
%union {
- uintmax_t uintval;
+ cdecl_uintmax uintval;
unsigned spectype;
- _Bool boolval;
- char *strval;
+ bool boolval;
struct cdecl_declspec *declspec;
struct cdecl_declarator *declarator;
struct cdecl *decl;
+ struct parse_item *item;
}
%{
struct cdecl_declspec *p;
while (x) {
p = x->next;
- free(x->ident);
free(x);
x = p;
}
switch (x->type) {
case CDECL_DECL_NULL:
- break;
+ x = NULL;
case CDECL_DECL_IDENT:
- free(x->u.ident);
+ case CDECL_DECL_ARRAY:
break;
case CDECL_DECL_POINTER:
free_declspec(x->u.pointer.qualifiers);
break;
- case CDECL_DECL_ARRAY:
- free(x->u.array.vla);
- break;
case CDECL_DECL_FUNCTION:
free_decl(x->u.function.parameters);
break;
a->next = b;
}
+/*
+ * Join three specifier lists into a single list, and returns the head of
+ * the new list.
+ *
+ * The list "b" is assumed to be a singleton list.
+ */
+static struct cdecl_declspec *join_specs3(struct cdecl_declspec *a,
+ struct cdecl_declspec *b,
+ struct cdecl_declspec *c)
+{
+ b->next = c;
+ join_specs(b, a);
+ return b;
+}
+
+/*
+ * Reverse the order of a "struct cdecl" list, and return the new first
+ * element of the list (i.e., the last element of the original list).
+ */
+static struct cdecl *reverse_decls(struct cdecl *decl)
+{
+ struct cdecl *prev, *next;
+
+ for (prev = NULL; decl; decl = next) {
+ next = decl->next;
+ decl->next = prev;
+ prev = decl;
+ }
+
+ return prev;
+}
+
/*
* Alter an abstract declarator (type name) to declare an identifier instead,
* used by the English parser rules to reduce "identifier as type" sequences.
*/
-static struct cdecl *insert_identifier(struct cdecl *decl, char *ident)
+static struct cdecl *
+insert_identifier(struct cdecl *decl, struct parse_item *ident)
{
- struct cdecl_declarator *d = decl->declarators;
-
- while (d->child)
- d = d->child;
+ struct cdecl_declarator *d, **p = &decl->declarators;
- d->type = CDECL_DECL_IDENT;
- d->u.ident = ident;
+ while ((d = *p)->child)
+ p = &d->child;
+ *p = &ident->u.declarator;
return decl;
}
+
+static struct cdecl_declarator *nulldecl(void)
+{
+ static const struct cdecl_declarator nulldecl = {0};
+ return (void *)&nulldecl;
+}
+#define NULLDECL (nulldecl())
+
%}
-%destructor { free($$); } <strval>
+%destructor { free($$); } <item>
%destructor { free_declspec($$); } <declspec>
%destructor { free_declarator($$); } <declarator>
%destructor { free_decl($$); } <decl>
/* Magic tokens */
-%token T_LEX_ERROR
+%token T_LEX_ERROR "@@@"
-%token <strval> T_IDENT "identifier"
-%token <uintval> T_UINT "integer constant"
+%token <item> T_IDENT "identifier"
+%token <uintval> T_UINT "integer constant"
%token T_SEMICOLON ";"
%token T_ASTERISK "*"
%token T_AS "as"
%token T_VLA "variable-length"
-%type <strval> vla_ident
+%type <item> vla_ident
%type <uintval> array_length
%type <boolval> varargs
%type <spectype> declspec_simple qualifier_simple
%type <spectype> typespec_simple typespec_tagged
%type <declspec> declspec_notype declspec_noid typespec_noid typespec
%type <declspec> qualifier qualifiers
-%type <declspec> declspecs declspecs_noid
+%type <declspec> declspecs declspecs_notype declspecs_noid
%type <declarator> direct_declarator declarator pointer array parens postfix
%type <declarator> direct_declarator_ish declarator_ish parameter_type_list
-%type <decl> declaration declarators declarator_wrap
-%type <decl> parameter
+%type <decl> cdecl declaration declarators declarator_wrap parameter
-%type <strval> english_vla
+%type <item> english_vla
%type <declspec> storage_func_specs post_specs
%type <declspec> type_qual_spec type_qual_specs typedef_name_qual
%type <declarator> english_declarator english_array english_function
%type <declarator> english_parameter_list null_decl
-%type <decl> english english_declaration
-%type <decl> english_parameter
+%type <decl> english english_declaration english_parameter
-/*
- * Harmless shift/reduce conflicts in english_parameter. See comments below
- * for more details.
- */
-%expect 2
+/* Precedence declaration to avoid conflict in english_parameter; see below. */
+%right T_TYPE
+%right T_IDENT
%%
-input: english {
- *out = $1;
-} | declaration {
- *out = $1;
-};
+input: cdecl { *out = $1; }
+cdecl: english | declaration
semi: | T_SEMICOLON
-
declaration: declspecs declarators semi {
- $$ = $2;
+ $$ = reverse_decls($2);
$$->specifiers = $1;
};
* unexpected parses; libcdecl applies a simplification step to the resulting
* parse tree afterwards.
*/
-declspecs: declspec_notype declspecs {
- $$ = $1;
- $$->next = $2;
-} | typespec declspecs_noid {
- $$ = $1;
- $$->next = $2;
+declspecs: declspecs_notype typespec declspecs_noid {
+ $$ = join_specs3($1, $2, $3);
}
-declspecs_noid: { $$ = NULL; } | declspec_noid declspecs_noid {
- $$ = $1;
- $$->next = $2;
+declspecs_notype: { $$ = NULL; } | declspecs_notype declspec_notype {
+ $$ = $2;
+ $$->next = $1;
+}
+
+declspecs_noid: { $$ = NULL; } | declspecs_noid declspec_noid {
+ $$ = $2;
+ $$->next = $1;
}
qualifiers: { $$ = NULL; } | qualifiers qualifier {
$$->next = $1;
}
-declarators: declarator_wrap | declarator_wrap T_COMMA declarators {
- $$ = $1;
- $$->next = $3;
+declarators: declarator_wrap | declarators T_COMMA declarator_wrap {
+ $$ = $3;
+ $$->next = $1;
}
declarator_wrap: declarator {
- ALLOC_STRUCT($$, struct cdecl, .declarators = $1);
+ ALLOC_DECL($$, NULL, $1);
}
declspec_simple: T_AUTO
| T_RESTRICT
| T_VOLATILE
-declspec_notype: qualifier | declspec_simple {
- ALLOC_STRUCT($$, struct cdecl_declspec, .type = $1);
-}
-
-typespec_noid: typespec_simple {
- ALLOC_STRUCT($$, struct cdecl_declspec, .type = $1);
-}
-
-qualifier: qualifier_simple {
- ALLOC_STRUCT($$, struct cdecl_declspec, .type = $1);
-}
+declspec_notype: qualifier | declspec_simple { ALLOC_DECLSPEC($$, $1); }
+typespec_noid: typespec_simple { ALLOC_DECLSPEC($$, $1); }
+qualifier: qualifier_simple { ALLOC_DECLSPEC($$, $1); }
typespec: typespec_noid | typespec_tagged T_IDENT {
- ALLOC_STRUCT($$, struct cdecl_declspec,
- .type = $1,
- .ident = $2);
+ /* Compiler should be able to elide this assignment. */
+ $2->u.declspec.ident = $2->u.declarator.u.ident;
+
+ $$ = &$2->u.declspec;
+ $$->type = $1;
}
declspec_noid: declspec_notype | typespec_noid
vla_ident: T_IDENT | T_ASTERISK {
- ALLOC($$, sizeof "");
- *$$ = 0;
+ if (!($$ = cdecl__alloc_item(1)))
+ YYERROR;
+ *$$->s = 0;
}
array: T_LBRACKET array_length T_RBRACKET {
- ALLOC_STRUCT($$, struct cdecl_declarator,
- .type = CDECL_DECL_ARRAY,
- .u.array.length = $2);
+ ALLOC_ARRAY($$, $2);
} | T_LBRACKET vla_ident T_RBRACKET {
- ALLOC_STRUCT($$, struct cdecl_declarator,
- .type = CDECL_DECL_ARRAY,
- .u.array.vla = $2);
+ $$ = &$2->u.declarator;
+ $$->type = CDECL_DECL_ARRAY;
+ $$->u.array.vla = $$->u.ident;
+ $$->u.array.length = 0;
}
parameter: declspecs declarator {
- ALLOC_STRUCT($$, struct cdecl,
- .specifiers = $1,
- .declarators = $2);
+ ALLOC_DECL($$, $1, $2);
}
varargs: { $$ = false; } | T_COMMA T_ELLIPSIS { $$ = true; }
-parameter_type_list: parameter varargs {
- ALLOC_STRUCT($$, struct cdecl_declarator,
- .type = CDECL_DECL_FUNCTION,
- .u.function.parameters = $1,
- .u.function.variadic = $2);
-} | parameter T_COMMA parameter_type_list {
- $$ = $3;
- $1->next = $$->u.function.parameters;
- $$->u.function.parameters = $1;
+parameter_type_list: parameter {
+ ALLOC_FUNCTION_($$, $1);
+} | parameter_type_list T_COMMA parameter {
+ $$ = $1;
+ $3->next = $$->u.function.parameters;
+ $$->u.function.parameters = $3;
}
-parens: T_LPAREN parameter_type_list T_RPAREN {
+parens: T_LPAREN parameter_type_list varargs T_RPAREN {
+ $2->u.function.parameters = reverse_decls($2->u.function.parameters);
+ $2->u.function.variadic = $3;
$$ = $2;
} | T_LPAREN declarator_ish T_RPAREN {
- ALLOC_STRUCT($$, struct cdecl_declarator,
- .type = CDECL_DECL_FUNCTION);
- ALLOC_STRUCT($$->u.function.parameters, struct cdecl,
- .declarators = $2);
+ struct cdecl *fake_params;
+
+ ALLOC_DECL(fake_params, NULL, $2);
+ ALLOC_FUNCTION_($$, fake_params);
}
pointer: T_ASTERISK qualifiers direct_declarator {
- ALLOC_STRUCT($$, struct cdecl_declarator,
- .type = CDECL_DECL_POINTER,
- .u.pointer.qualifiers = $2,
- .child = $3);
+ ALLOC_POINTER($$, $2, $3);
} | T_ASTERISK qualifiers pointer {
- ALLOC_STRUCT($$, struct cdecl_declarator,
- .type = CDECL_DECL_POINTER,
- .u.pointer.qualifiers = $2,
- .child = $3);
+ ALLOC_POINTER($$, $2, $3);
}
declarator: direct_declarator | pointer
postfix: array | parens
direct_declarator_ish: {
- ALLOC_STRUCT($$, struct cdecl_declarator,
- .type = CDECL_DECL_NULL);
+ $$ = NULLDECL;
} | direct_declarator_ish postfix {
$$ = $2;
$$->child = $1;
}
direct_declarator: {
- ALLOC_STRUCT($$, struct cdecl_declarator,
- .type = CDECL_DECL_NULL);
+ $$ = NULLDECL;
} | T_IDENT {
- ALLOC_STRUCT($$, struct cdecl_declarator,
- .type = CDECL_DECL_IDENT,
- .u.ident = $1);
+ $$ = &$1->u.declarator;
} | direct_declarator postfix {
$$ = $2;
$$->child = $1;
$$ = $2;
}
-storage_func_specs: { $$ = NULL; } | declspec_simple storage_func_specs {
- ALLOC_STRUCT($$, struct cdecl_declspec,
- .type = $1,
- .next = $2);
+/*
+ * We use a precedence declaration to prefer shifting an identifier
+ * over reducing this empty rule; see below.
+ */
+storage_func_specs: %prec T_TYPE { $$ = NULL; }
+storage_func_specs: storage_func_specs declspec_simple {
+ ALLOC_DECLSPEC($$, $2);
+ $$->next = $1;
}
type_qual_spec: typespec_noid | qualifier
-type_qual_specs: { $$ = NULL; } | type_qual_spec type_qual_specs {
- $$ = $1;
- $$->next = $2;
+type_qual_specs: { $$ = NULL; } | type_qual_specs type_qual_spec {
+ $$ = $2;
+ $$->next = $1;
}
/*
* together three different specifiers lists.
*/
post_specs: qualifiers typespec type_qual_specs {
- $2->next = $3;
- join_specs($2, $1);
- $$ = $2;
+ $$ = join_specs3($1, $2, $3);
}
english_declaration: storage_func_specs english_declarator post_specs {
join_specs($3, $1);
- ALLOC_STRUCT($$, struct cdecl,
- .specifiers = $3,
- .declarators = $2);
+ ALLOC_DECL($$, $3, $2);
}
english_declarator: {
- ALLOC_STRUCT($$, struct cdecl_declarator,
- .type = CDECL_DECL_NULL);
+ $$ = NULLDECL;
} | english_declarator qualifiers T_POINTER T_TO {
- ALLOC_STRUCT($$, struct cdecl_declarator,
- .type = CDECL_DECL_POINTER,
- .child = $1,
- .u.pointer.qualifiers = $2);
+ ALLOC_POINTER($$, $2, $1);
} | english_declarator english_array {
$$ = $2;
$$->child = $1;
}
english_function: T_FUNCTION T_RETURNING {
- ALLOC_STRUCT($$, struct cdecl_declarator,
- .type = CDECL_DECL_FUNCTION,
- .u.function.parameters = NULL);
-} | T_FUNCTION T_LPAREN english_parameter_list T_RPAREN T_RETURNING {
+ ALLOC_FUNCTION($$, NULL, false);
+} | T_FUNCTION T_LPAREN english_parameter_list varargs T_RPAREN T_RETURNING {
+ $3->u.function.parameters = reverse_decls($3->u.function.parameters);
+ $3->u.function.variadic = $4;
$$ = $3;
}
-english_parameter_list: english_parameter varargs {
- ALLOC_STRUCT($$, struct cdecl_declarator,
- .type = CDECL_DECL_FUNCTION,
- .u.function.parameters = $1,
- .u.function.variadic = $2);
-} | english_parameter T_COMMA english_parameter_list {
- $$ = $3;
- $1->next = $$->u.function.parameters;
- $$->u.function.parameters = $1;
+english_parameter_list: english_parameter {
+ ALLOC_FUNCTION_($$, $1);
+} | english_parameter_list T_COMMA english_parameter {
+ $$ = $1;
+ $3->next = $$->u.function.parameters;
+ $$->u.function.parameters = $3;
}
typedef_name_qual: T_IDENT qualifiers {
- ALLOC_STRUCT($$, struct cdecl_declspec,
- .type = CDECL_TYPE_IDENT,
- .ident = $1,
- .next = $2);
+ /* Compiler should be able to elide this assignment. */
+ $1->u.declspec.ident = $1->u.declarator.u.ident;
+
+ $$ = &$1->u.declspec;
+ $$->type = CDECL_TYPE_IDENT;
+ $$->next = $2;
}
null_decl: {
- ALLOC_STRUCT($$, struct cdecl_declarator,
- .type = CDECL_DECL_NULL);
+ $$ = NULLDECL;
}
/*
- * There is a small shift/reduce conflict here. An unadorned identifier
- * as the first thing in the parameter might be a typedef name deep in the
- * first english_declaration (thus empty storage_func_specs and empty
- * english_declarator need to be reduced) or it might be the identifier
- * before the "as" (thus the identifier should be shifted).
+ * There is a shift/reduce conflict here when an identifier appears as the
+ * first token. The conflict is between shifting T_IDENT, or reducing the
+ * empty production for storage_func_specs (cf. english_declaration).
+ *
+ * - In either case, if we reduce, we won't match T_IDENT T_AS since the
+ * stack now has the extra storage_func_specs nonterminal symbol.
+ * - And if we shift, we won't match english_declaration since it is
+ * too late to add storage_func_specs to the stack.
*
- * The typedef name conflict is the only issue, so treating it as a special
- * case makes the shift harmless.
+ * The only valid input affected by the conflict is a simple type names,
+ * possibly followed by qualifiers. So the conflict is adequately resolved
+ * by shifting, so long as we have a special-case reduction to handle this.
*/
english_parameter: english_declaration | typedef_name_qual null_decl {
- ALLOC_STRUCT($$, struct cdecl,
- .specifiers = $1,
- .declarators = $2);
+ ALLOC_DECL($$, $1, $2);
} | T_IDENT T_AS english_declaration {
$$ = insert_identifier($3, $1);
}
english_array: T_VLA T_ARRAY english_vla T_OF {
- ALLOC_STRUCT($$, struct cdecl_declarator,
- .type = CDECL_DECL_ARRAY,
- .u.array.vla = $3);
+ $$ = &$3->u.declarator;
+ $$->type = CDECL_DECL_ARRAY;
+ $$->u.array.vla = $$->u.ident;
+ $$->u.array.length = 0;
} | T_ARRAY array_length T_OF {
- ALLOC_STRUCT($$, struct cdecl_declarator,
- .type = CDECL_DECL_ARRAY,
- .u.array.length = $2);
+ ALLOC_ARRAY($$, $2);
}
array_length: { $$ = 0; }
array_length: T_UINT {
- if (!($$ = $1))
- FAIL(_("array length must be positive"));
+ if (!($$ = $1)) {
+ cdecl__errmsg(CDECL__EZEROARRAY);
+ YYERROR;
+ }
}
english_vla: T_IDENT | {
- ALLOC($$, sizeof "");
- *$$ = 0;
+ if (!($$ = cdecl__alloc_item(1)))
+ YYERROR;
+ *$$->s = 0;
}
%%
return yytname[YYTRANSLATE(token)];
}
-static void
+/*
+ * Current versions of GCC (up to 13) want to inline this function into the
+ * parser even when optimizing for size and the results are not great, so
+ * try to prevent such inlining.
+ */
+CDECL__NOINLINE static void
yyerror(YYLTYPE *loc, yyscan_t scanner, struct cdecl **out, const char *err)
{
if (strstr(err, yytname[YYTRANSLATE(T_LEX_ERROR)]))
return;
- cdecl__err(CDECL_ENOPARSE, "%s", err);
+ cdecl__err("%s", err);
}
projects / cdecl99.git / blobdiff