X-Git-Url: https://git.draconx.ca/gitweb/cdecl99.git/blobdiff_plain/362559e5c1b4d138305f9edf2c2b7ee1a24a08f6..21bc2db0ec83b235caec38d42f4d0812f473d766:/src/parse.y?ds=inline
diff --git a/src/parse.y b/src/parse.y
index 70e1878..ba9bf22 100644
--- a/src/parse.y
+++ b/src/parse.y
@@ -1,6 +1,7 @@
+%code top {
/*
* Parser for C declarations.
- * Copyright © 2011 Nick Bowler
+ * Copyright © 2011-2012, 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
@@ -15,29 +16,598 @@
* You should have received a copy of the GNU General Public License
* along with this program. If not, see .
*/
+}
+%name-prefix "cdecl__yy"
+%parse-param {void *scanner}
+%parse-param {struct cdecl **out}
+%lex-param {yyscan_t scanner}
%define api.pure
%error-verbose
%locations
%{
+#include
+#include
+#include
+
#include "scan.h"
+#include "cdecl.h"
+#include "cdecl-internal.h"
+#include "errmsg.h"
+
+#define FAIL(msg) do { \
+ yyerror(&yylloc, NULL, NULL, msg); \
+ YYERROR; \
+} while (0)
+
+#define ALLOC(ptr, size) do { \
+ (ptr) = malloc(size); \
+ if (!(ptr)) { \
+ cdecl__errmsg(CDECL__ENOMEM); \
+ YYERROR; \
+ } \
+} while (0)
+
+#define ALLOC_STRUCT(ptr, type, ...) do { \
+ ALLOC(ptr, sizeof (type)); \
+ *(ptr) = (type) { __VA_ARGS__ }; \
+} while (0)
+
+/*
+ * With the postprocessing performed by fix-yytname.awk, all the symbol
+ * 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)
%}
+%code requires {
+#include
+}
+
%code provides {
-void yyerror(const char *);
+void cdecl__free(struct cdecl *);
+int cdecl__yyparse(void *scanner, struct cdecl **out);
+const char *cdecl__token_name(unsigned token);
}
%union {
- int foo;
+ uintmax_t uintval;
+ unsigned spectype;
+ _Bool boolval;
+ struct cdecl_declspec *declspec;
+ struct cdecl_declarator *declarator;
+ struct cdecl *decl;
+ struct parse_item *item;
+}
+
+%{
+static void yyerror(YYLTYPE *, yyscan_t, struct cdecl **, const char *);
+static void free_decl(struct cdecl *);
+
+static void free_declspec(struct cdecl_declspec *x)
+{
+ struct cdecl_declspec *p;
+ while (x) {
+ p = x->next;
+ free(x);
+ x = p;
+ }
+}
+
+static void free_declarator(struct cdecl_declarator *x)
+{
+ struct cdecl_declarator *p;
+
+ while (x) {
+ p = x->child;
+
+ switch (x->type) {
+ case CDECL_DECL_NULL:
+ x = NULL;
+ case CDECL_DECL_IDENT:
+ case CDECL_DECL_ARRAY:
+ break;
+ case CDECL_DECL_POINTER:
+ free_declspec(x->u.pointer.qualifiers);
+ break;
+ case CDECL_DECL_FUNCTION:
+ free_decl(x->u.function.parameters);
+ break;
+ default:
+ assert(0);
+ }
+
+ free(x);
+ x = p;
+ }
+}
+
+static void free_decl(struct cdecl *x)
+{
+ struct cdecl *p;
+
+ while (x) {
+ p = x->next;
+
+ /* The specifiers may be shared by an entire chain. */
+ if (!p || p->specifiers != x->specifiers)
+ free_declspec(x->specifiers);
+
+ free_declarator(x->declarators);
+ free(x);
+ x = p;
+ }
+}
+
+void cdecl__free(struct cdecl *decl)
+{
+ free_decl(decl);
}
+/*
+ * Join two declaration specifier lists into a single list, with "a" being the
+ * head of the new list.
+ *
+ * The list "a" is assumed to be nonempty.
+ */
+static void join_specs(struct cdecl_declspec *a, struct cdecl_declspec *b)
+{
+ while (a->next)
+ a = a->next;
+ a->next = b;
+}
+
+/*
+ * 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, struct parse_item *ident)
+{
+ struct cdecl_declarator *d, **p = &decl->declarators;
+
+ 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($$); } -
+%destructor { free_declspec($$); }
+%destructor { free_declarator($$); }
+%destructor { free_decl($$); }
+
+/* Magic tokens */
+%token T_LEX_ERROR
+
+%token
- T_IDENT "identifier"
+%token T_UINT "integer constant"
+
+%token T_SEMICOLON ";"
+%token T_ASTERISK "*"
+%token T_LPAREN "("
+%token T_RPAREN ")"
+%token T_LBRACKET "["
+%token T_RBRACKET "]"
+%token T_COMMA ","
+%token T_ELLIPSIS "..."
+
+%token T_TYPEDEF "typedef"
+%token T_EXTERN "extern"
+%token T_STATIC "static"
+%token T_AUTO "auto"
+%token T_REGISTER "register"
+
+%token T_INLINE "inline"
+
+%token T_RESTRICT "restrict"
+%token T_VOLATILE "volatile"
+%token T_CONST "const"
+
+%token T_VOID "void"
+%token T_CHAR "char"
+%token T_SHORT "short"
+%token T_INT "int"
+%token T_LONG "long"
+%token T_FLOAT "float"
+%token T_DOUBLE "double"
+%token T_SIGNED "signed"
+%token T_UNSIGNED "unsigned"
+%token T_BOOL "_Bool"
+%token T_COMPLEX "_Complex"
+%token T_IMAGINARY "_Imaginary"
+
+%token T_STRUCT "struct"
+%token T_UNION "union"
+%token T_ENUM "enum"
+
+/*
+ * English keywords.
+ */
+%token T_TYPE "type"
+%token T_DECLARE "declare"
+%token T_POINTER "pointer"
+%token T_FUNCTION "function"
+%token T_RETURNING "returning"
+%token T_ARRAY "array"
+%token T_TO "to"
+%token T_OF "of"
+%token T_AS "as"
+%token T_VLA "variable-length"
+
+%type
- vla_ident
+%type array_length
+%type varargs
+%type declspec_simple qualifier_simple
+%type typespec_simple typespec_tagged
+%type declspec_notype declspec_noid typespec_noid typespec
+%type qualifier qualifiers
+%type declspecs declspecs_noid
+%type direct_declarator declarator pointer array parens postfix
+%type direct_declarator_ish declarator_ish parameter_type_list
+%type declaration declarators declarator_wrap
+%type parameter
+
+%type
- english_vla
+%type storage_func_specs post_specs
+%type type_qual_spec type_qual_specs typedef_name_qual
+%type english_declarator english_array english_function
+%type english_parameter_list null_decl
+%type english english_declaration
+%type english_parameter
+
+/* Precedence declaration to avoid conflict in english_parameter; see below. */
+%right T_TYPE
+%right T_IDENT
+
%%
-input: ;
+input: english {
+ *out = $1;
+} | declaration {
+ *out = $1;
+};
+
+semi: | T_SEMICOLON
+
+declaration: declspecs declarators semi {
+ $$ = $2;
+ $$->specifiers = $1;
+};
+
+/*
+ * We support parsing declarations using arbitrary identifiers as type
+ * specifiers (a la C typedef). To avoid confusion with identifiers that
+ * may also be used as declarators, note the following:
+ *
+ * (a) Every valid C declaration must have at least one type specifier, and
+ * (b) Valid declarations with typedef names have exactly one type specifier.
+ *
+ * So the rule applied when parsing specifiers is: an identifier is a type
+ * specifier only if we have not yet seen any type specifiers whatsoever
+ * (within one declaration specifier list).
+ *
+ * Treating identifiers as type specifiers by default can lead to strange and
+ * 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_noid: { $$ = NULL; } | declspec_noid declspecs_noid {
+ $$ = $1;
+ $$->next = $2;
+}
+
+qualifiers: { $$ = NULL; } | qualifiers qualifier {
+ $$ = $2;
+ $$->next = $1;
+}
+
+declarators: declarator_wrap | declarator_wrap T_COMMA declarators {
+ $$ = $1;
+ $$->next = $3;
+}
+
+declarator_wrap: declarator {
+ ALLOC_STRUCT($$, struct cdecl, .declarators = $1);
+}
+
+declspec_simple: T_AUTO
+ | T_TYPEDEF
+ | T_EXTERN
+ | T_STATIC
+ | T_REGISTER
+ | T_INLINE
+
+typespec_simple: T_VOID
+ | T_CHAR
+ | T_SHORT
+ | T_INT
+ | T_LONG
+ | T_FLOAT
+ | T_DOUBLE
+ | T_SIGNED
+ | T_UNSIGNED
+ | T_BOOL
+ | T_COMPLEX
+ | T_IMAGINARY
+
+typespec_tagged: T_STRUCT | T_UNION | T_ENUM | { $$ = CDECL_TYPE_IDENT; }
+
+qualifier_simple: T_CONST
+ | 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($$, struct cdecl_declspec, .type = $1);
+}
+
+typespec: typespec_noid | typespec_tagged T_IDENT {
+ /* Compiler should be able to elide this assignment. */
+ $2->u.declspec.ident = $2->u.declarator.u.ident;
+
+ $$ = &$2->u.declspec;
+ $$->type = $1;
+}
+
+declspec_noid: declspec_notype | typespec_noid
+
+vla_ident: T_IDENT | T_ASTERISK {
+ if (!($$ = 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);
+} | T_LBRACKET vla_ident T_RBRACKET {
+ $$ = &$2->u.declarator;
+ $$->type = CDECL_DECL_ARRAY;
+ $$->u.array.vla = $$->u.ident;
+ $$->u.array.length = 0;
+}
+
+parameter: declspecs declarator {
+ ALLOC_STRUCT($$, struct cdecl,
+ .specifiers = $1,
+ .declarators = $2);
+}
+
+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;
+}
+
+parens: T_LPAREN parameter_type_list T_RPAREN {
+ $$ = $2;
+} | T_LPAREN declarator_ish T_RPAREN {
+ ALLOC_STRUCT($$, struct cdecl_declarator,
+ .type = CDECL_DECL_FUNCTION);
+ ALLOC_STRUCT($$->u.function.parameters, struct cdecl,
+ .declarators = $2);
+}
+
+pointer: T_ASTERISK qualifiers direct_declarator {
+ ALLOC_STRUCT($$, struct cdecl_declarator,
+ .type = CDECL_DECL_POINTER,
+ .u.pointer.qualifiers = $2,
+ .child = $3);
+} | T_ASTERISK qualifiers pointer {
+ ALLOC_STRUCT($$, struct cdecl_declarator,
+ .type = CDECL_DECL_POINTER,
+ .u.pointer.qualifiers = $2,
+ .child = $3);
+}
+
+declarator: direct_declarator | pointer
+declarator_ish: direct_declarator_ish | pointer
+postfix: array | parens
+
+direct_declarator_ish: {
+ $$ = NULLDECL;
+} | direct_declarator_ish postfix {
+ $$ = $2;
+ $$->child = $1;
+}
+
+direct_declarator: {
+ $$ = NULLDECL;
+} | T_IDENT {
+ $$ = &$1->u.declarator;
+} | direct_declarator postfix {
+ $$ = $2;
+ $$->child = $1;
+}
+
+english: T_DECLARE T_IDENT T_AS english_declaration {
+ $$ = insert_identifier($4, $2);
+} | T_TYPE english_declaration {
+ $$ = $2;
+}
+
+/*
+ * We use a precedence declaration to prefer shifting an identifier
+ * over reducing this empty rule; see below.
+ */
+storage_func_specs: %prec T_TYPE { $$ = NULL; }
+storage_func_specs: declspec_simple storage_func_specs {
+ ALLOC_STRUCT($$, struct cdecl_declspec,
+ .type = $1,
+ .next = $2);
+}
+
+type_qual_spec: typespec_noid | qualifier
+
+type_qual_specs: { $$ = NULL; } | type_qual_spec type_qual_specs {
+ $$ = $1;
+ $$->next = $2;
+}
+
+/*
+ * The "qualifiers" nonterminal needs to be used here to avoid shift/reduce
+ * conflicts with pointer declarators. So we end up needing to stitch
+ * together three different specifiers lists.
+ */
+post_specs: qualifiers typespec type_qual_specs {
+ $2->next = $3;
+ join_specs($2, $1);
+ $$ = $2;
+}
+
+english_declaration: storage_func_specs english_declarator post_specs {
+ join_specs($3, $1);
+ ALLOC_STRUCT($$, struct cdecl,
+ .specifiers = $3,
+ .declarators = $2);
+}
+
+english_declarator: {
+ $$ = NULLDECL;
+} | english_declarator qualifiers T_POINTER T_TO {
+ ALLOC_STRUCT($$, struct cdecl_declarator,
+ .type = CDECL_DECL_POINTER,
+ .child = $1,
+ .u.pointer.qualifiers = $2);
+} | english_declarator english_array {
+ $$ = $2;
+ $$->child = $1;
+} | english_declarator english_function {
+ $$ = $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 {
+ $$ = $3;
+}
+
+english_parameter_list: english_parameter varargs {
+ ALLOC_STRUCT($$, 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;
+ $$->u.function.parameters = $1;
+}
+
+typedef_name_qual: T_IDENT qualifiers {
+ /* Compiler should be able to elide this assignment. */
+ $1->u.declspec.ident = $1->u.declarator.u.ident;
+
+ $$ = &$1->u.declspec;
+ $$->type = CDECL_TYPE_IDENT;
+ $$->next = $2;
+}
+
+null_decl: {
+ $$ = NULLDECL;
+}
+
+/*
+ * There is a shift/reduce conflict here when an identifier appears as the
+ * first token. The conflict is between shifting T_IDENT, or reducing the
+ * empty production for storage_func_specs (cf. english_declaration).
+ *
+ * - In either case, if we reduce, we won't match T_IDENT T_AS since the
+ * stack now has the extra storage_func_specs nonterminal symbol.
+ * - And if we shift, we won't match english_declaration since it is
+ * too late to add storage_func_specs to the stack.
+ *
+ * The only valid input affected by the conflict is a simple type names,
+ * possibly followed by qualifiers. So the conflict is adequately resolved
+ * by shifting, so long as we have a special-case reduction to handle this.
+ */
+english_parameter: english_declaration | typedef_name_qual null_decl {
+ ALLOC_STRUCT($$, struct cdecl,
+ .specifiers = $1,
+ .declarators = $2);
+} | T_IDENT T_AS english_declaration {
+ $$ = insert_identifier($3, $1);
+}
+
+english_array: T_VLA T_ARRAY english_vla T_OF {
+ $$ = &$3->u.declarator;
+ $$->type = CDECL_DECL_ARRAY;
+ $$->u.array.vla = $$->u.ident;
+ $$->u.array.length = 0;
+} | T_ARRAY array_length T_OF {
+ ALLOC_STRUCT($$, struct cdecl_declarator,
+ .type = CDECL_DECL_ARRAY,
+ .u.array.length = $2);
+}
+
+array_length: { $$ = 0; }
+array_length: T_UINT {
+ if (!($$ = $1))
+ FAIL(_("array length must be positive"));
+}
+
+english_vla: T_IDENT | {
+ if (!($$ = cdecl__alloc_item(1)))
+ YYERROR;
+ *$$->s = 0;
+}
%%
-void yyerror(const char *err)
+
+/*
+ * Expose the token string table to the rest of the library, in order to
+ * produce strings that match parser keywords.
+ *
+ * In order for this to work properly, the Bison output must be postprocessed
+ * by fix-yytname.awk to remove pointless quotation marks from the keyword
+ * strings.
+ */
+const char *cdecl__token_name(unsigned token)
{
- fprintf(stderr, "%s\n", err);
+ return yytname[YYTRANSLATE(token)];
+}
+
+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);
}