c-parse.y

使用yacc和lex编写的cmm语言的词法分析和语法分析程序.

		{ $$ = parser_build_binary_op ($2, $1, $3); }
	| expr_no_commas '|' expr_no_commas
		{ $$ = parser_build_binary_op ($2, $1, $3); }
	| expr_no_commas '^' expr_no_commas
		{ $$ = parser_build_binary_op ($2, $1, $3); }
	| expr_no_commas ANDAND expr_no_commas
		{ $$ = parser_build_binary_op (TRUTH_ANDIF_EXPR, $1, $3); }
	| expr_no_commas OROR expr_no_commas
		{ $$ = parser_build_binary_op (TRUTH_ORIF_EXPR, $1, $3); }
	| expr_no_commas '?' xexpr ':' expr_no_commas
		{ $$ = build_conditional_expr ($1, $3, $5); }
	| expr_no_commas '=' expr_no_commas
		{ $$ = build_modify_expr ($1, NOP_EXPR, $3); }
	| expr_no_commas ASSIGN expr_no_commas
		{ $$ = build_modify_expr ($1, $2, $3); }
	;

primary:
	IDENTIFIER
		{
		  tree context;

		  $$ = lastiddecl;
		  if (!$$ || $$ == error_mark_node)
		    {
		      if (yychar == YYEMPTY)
			yychar = YYLEX;
		      if (yychar == '(')
			{
			  $$ = implicitly_declare ($1);
			  assemble_external ($$);
			  TREE_USED ($$) = 1;
			}
		      else if (current_function_decl == 0)
			{
			  error ("`%s' undeclared, outside of functions",
				 IDENTIFIER_POINTER ($1));
			  $$ = error_mark_node;
			}
		      else
			{
			  if (IDENTIFIER_GLOBAL_VALUE ($1) != error_mark_node
			      || IDENTIFIER_ERROR_LOCUS ($1) != current_function_decl)
			    {
			      error ("`%s' undeclared (first use this function)",
				     IDENTIFIER_POINTER ($1));

			      if (! undeclared_variable_notice)
				{
				  error ("(Each undeclared identifier is reported only once");
				  error ("for each function it appears in.)");
				  undeclared_variable_notice = 1;
				}
			    }
			  $$ = error_mark_node;
			  /* Prevent repeated error messages.  */
			  IDENTIFIER_GLOBAL_VALUE ($1) = error_mark_node;
			  IDENTIFIER_ERROR_LOCUS ($1) = current_function_decl;
			}
		    }
		  else if (TREE_TYPE ($$) == error_mark_node)
		    $$ = error_mark_node;
		  else if (! TREE_USED ($$))
		    {
		      if (TREE_EXTERNAL ($$))
			assemble_external ($$);
		      TREE_USED ($$) = 1;
		    }
		  if (TREE_CODE ($$) == CONST_DECL)
		    $$ = DECL_INITIAL ($$);
		}
	| CONSTANT
	| string
		{ $$ = combine_strings ($1); }
	| '(' expr ')'
		{ char class = TREE_CODE_CLASS (TREE_CODE ($2));
		  if (class == 'e' || class == '1'
		      || class == '2' || class == '<')
		    C_SET_EXP_ORIGINAL_CODE ($2, ERROR_MARK);
		  $$ = $2; }
	| '(' error ')'
		{ $$ = error_mark_node; }
	| '('
		{ if (current_function_decl == 0)
		    {
		      error ("braced-group within expression allowed only inside a function");
		      YYERROR;
		    }
		  /* We must force a BLOCK for this level
		     so that, if it is not expanded later,
		     there is a way to turn off the entire subtree of blocks
		     that are contained in it.  */
		  keep_next_level ();
		  push_label_level ();
		  $<ttype>$ = expand_start_stmt_expr (); }
	  compstmt ')'
		{ tree rtl_exp;
		  if (pedantic)
		    pedwarn ("ANSI C forbids braced-groups within expressions");
		  pop_label_level ();
		  rtl_exp = expand_end_stmt_expr ($<ttype>2);
		  /* The statements have side effects, so the group does.  */
		  TREE_SIDE_EFFECTS (rtl_exp) = 1;

		  /* Make a BIND_EXPR for the BLOCK already made.  */
		  $$ = build (BIND_EXPR, TREE_TYPE (rtl_exp),
			      NULL_TREE, rtl_exp, $3);
		}
	| primary '(' exprlist ')'   %prec '.'
		{ $$ = build_function_call ($1, $3); }
	| primary '[' expr ']'   %prec '.'
		{ $$ = build_array_ref ($1, $3); }
	| primary '.' identifier
		{ $$ = build_component_ref ($1, $3); }
	| primary POINTSAT identifier
		{ $$ = build_component_ref (build_indirect_ref ($1, "->"), $3); }
	| primary PLUSPLUS
		{ $$ = build_unary_op (POSTINCREMENT_EXPR, $1, 0); }
	| primary MINUSMINUS
		{ $$ = build_unary_op (POSTDECREMENT_EXPR, $1, 0); }
	;

/* Produces a STRING_CST with perhaps more STRING_CSTs chained onto it.  */
string:
	  STRING
	| string STRING
		{ $$ = chainon ($1, $2); }
	;

xdecls:
	/* empty */
	| datadecls
	| datadecls ELLIPSIS
		/* ... is used here to indicate a varargs function.  */
		{ c_mark_varargs ();
		  if (pedantic)
		    pedwarn ("ANSI C does not permit use of `varargs.h'"); }
	;

/* The following are analogous to lineno_decl, decls and decl
   except that they do not allow nested functions.
   They are used for old-style parm decls.  */
lineno_datadecl:
	  save_filename save_lineno datadecl
		{ }
	;

datadecls:
	lineno_datadecl
	| errstmt
	| datadecls lineno_datadecl
	| lineno_datadecl errstmt
	;

datadecl:
	typed_declspecs setspecs initdecls ';'
		{ current_declspecs = TREE_VALUE (declspec_stack);
		  declspec_stack = TREE_CHAIN (declspec_stack);
		  resume_momentary ($2); }
	| declmods setspecs notype_initdecls ';'
		{ current_declspecs = TREE_VALUE (declspec_stack);
		  declspec_stack = TREE_CHAIN (declspec_stack);
		  resume_momentary ($2); }
	| typed_declspecs ';'
		{ shadow_tag ($1); }
	| declmods ';'
		{ pedwarn ("empty declaration"); }
	;

/* This combination which saves a lineno before a decl
   is the normal thing to use, rather than decl itself.
   This is to avoid shift/reduce conflicts in contexts
   where statement labels are allowed.  */
lineno_decl:
	  save_filename save_lineno decl
		{ }
	;

decls:
	lineno_decl
	| errstmt
	| decls lineno_decl
	| lineno_decl errstmt
	;

/* records the type and storage class specs to use for processing
   the declarators that follow.
   Maintains a stack of outer-level values of current_declspecs,
   for the sake of parm declarations nested in function declarators.  */
setspecs: /* empty */
		{ $$ = suspend_momentary ();
		  pending_xref_error ();
		  declspec_stack = tree_cons (0, current_declspecs,
					      declspec_stack);
		  current_declspecs = $<ttype>0; }
	;

decl:
	typed_declspecs setspecs initdecls ';'
		{ current_declspecs = TREE_VALUE (declspec_stack);
		  declspec_stack = TREE_CHAIN (declspec_stack);
		  resume_momentary ($2); }
	| declmods setspecs notype_initdecls ';'
		{ current_declspecs = TREE_VALUE (declspec_stack);
		  declspec_stack = TREE_CHAIN (declspec_stack);
		  resume_momentary ($2); }
	| typed_declspecs setspecs nested_function
		{ current_declspecs = TREE_VALUE (declspec_stack);
		  declspec_stack = TREE_CHAIN (declspec_stack);
		  resume_momentary ($2); }
	| declmods setspecs notype_nested_function
		{ current_declspecs = TREE_VALUE (declspec_stack);
		  declspec_stack = TREE_CHAIN (declspec_stack);
		  resume_momentary ($2); }
	| typed_declspecs ';'
		{ shadow_tag ($1); }
	| declmods ';'
		{ pedwarn ("empty declaration"); }
	;

/* Declspecs which contain at least one type specifier or typedef name.
   (Just `const' or `volatile' is not enough.)
   A typedef'd name following these is taken as a name to be declared.  */

typed_declspecs:
	  typespec reserved_declspecs
		{ $$ = tree_cons (NULL_TREE, $1, $2); }
	| declmods typespec reserved_declspecs
		{ $$ = chainon ($3, tree_cons (NULL_TREE, $2, $1)); }
	;

reserved_declspecs:  /* empty */
		{ $$ = NULL_TREE; }
	| reserved_declspecs typespecqual_reserved
		{ $$ = tree_cons (NULL_TREE, $2, $1); }
	| reserved_declspecs SCSPEC
		{ $$ = tree_cons (NULL_TREE, $2, $1); }
	;

/* List of just storage classes and type modifiers.
   A declaration can start with just this, but then it cannot be used
   to redeclare a typedef-name.  */

declmods:
	  TYPE_QUAL
		{ $$ = tree_cons (NULL_TREE, $1, NULL_TREE); }
	| SCSPEC
		{ $$ = tree_cons (NULL_TREE, $1, NULL_TREE); }
	| declmods TYPE_QUAL
		{ $$ = tree_cons (NULL_TREE, $2, $1); }
	| declmods SCSPEC
		{ $$ = tree_cons (NULL_TREE, $2, $1); }
	;


/* Used instead of declspecs where storage classes are not allowed
   (that is, for typenames and structure components).
   Don't accept a typedef-name if anything but a modifier precedes it.  */

typed_typespecs:
	  typespec reserved_typespecquals
		{ $$ = tree_cons (NULL_TREE, $1, $2); }
	| nonempty_type_quals typespec reserved_typespecquals
		{ $$ = chainon ($3, tree_cons (NULL_TREE, $2, $1)); }
	;

reserved_typespecquals:  /* empty */
		{ $$ = NULL_TREE; }
	| reserved_typespecquals typespecqual_reserved
		{ $$ = tree_cons (NULL_TREE, $2, $1); }
	;

/* A typespec (but not a type qualifier).
   Once we have seen one of these in a declaration,
   if a typedef name appears then it is being redeclared.  */

typespec: TYPESPEC
	| structsp
	| TYPENAME
		{ /* For a typedef name, record the meaning, not the name.
		     In case of `foo foo, bar;'.  */
		  $$ = lookup_name ($1); }
	| TYPEOF '(' expr ')'
		{ $$ = TREE_TYPE ($3);
		  if (pedantic)
		    pedwarn ("ANSI C forbids `typeof'"); }
	| TYPEOF '(' typename ')'
		{ $$ = groktypename ($3);
		  if (pedantic)
		    pedwarn ("ANSI C forbids `typeof'"); }
	;

/* A typespec that is a reserved word, or a type qualifier.  */

typespecqual_reserved: TYPESPEC
	| TYPE_QUAL
	| structsp
	;

initdecls:
	initdcl
	| initdecls ',' initdcl
	;

notype_initdecls:
	notype_initdcl
	| notype_initdecls ',' initdcl
	;

maybeasm:
	  /* empty */
		{ $$ = NULL_TREE; }
	| ASM '(' string ')'
		{ if (TREE_CHAIN ($3)) $3 = combine_strings ($3);
		  $$ = $3;
		}
	;

initdcl:
	  declarator maybeasm maybe_attribute '='
		{ $<ttype>$ = start_decl ($1, current_declspecs, 1); }
	  init
/* Note how the declaration of the variable is in effect while its init is parsed! */
		{ decl_attributes ($<ttype>5, $3);
		  finish_decl ($<ttype>5, $6, $2); }
	| declarator maybeasm maybe_attribute
		{ tree d = start_decl ($1, current_declspecs, 0);
		  decl_attributes (d, $3);
		  finish_decl (d, NULL_TREE, $2); }
	;

notype_initdcl:
	  notype_declarator maybeasm maybe_attribute '='
		{ $<ttype>$ = start_decl ($1, current_declspecs, 1); }
	  init
/* Note how the declaration of the variable is in effect while its init is parsed! */
		{ decl_attributes ($<ttype>5, $3);
		  finish_decl ($<ttype>5, $6, $2); }
	| notype_declarator maybeasm maybe_attribute
		{ tree d = start_decl ($1, current_declspecs, 0);
		  decl_attributes (d, $3);
		  finish_decl (d, NULL_TREE, $2); }
	;
/* the * rules are dummies to accept the Apollo extended syntax
   so that the header files compile. */
maybe_attribute:
    /* empty */
		{ $$ = NULL_TREE; }
    | ATTRIBUTE '(' '(' attribute_list ')' ')'
		{ $$ = $4; }
    ;

attribute_list
    : attrib
	{ $$ = tree_cons (NULL_TREE, $1, NULL_TREE); }
    | attribute_list ',' attrib
	{ $$ = tree_cons (NULL_TREE, $3, $1); }
    ;

attrib
    : IDENTIFIER
	{ if (strcmp (IDENTIFIER_POINTER ($1), "packed"))
	    warning ("`%s' attribute directive ignored",
		     IDENTIFIER_POINTER ($1));
	  $$ = $1; }
    | IDENTIFIER '(' CONSTANT ')'
	{ /* if not "aligned(n)", then issue warning */
	  if (strcmp (IDENTIFIER_POINTER ($1), "aligned") != 0
	      || TREE_CODE ($3) != INTEGER_CST)
	    {
	      warning ("`%s' attribute directive ignored",
		       IDENTIFIER_POINTER ($1));
	      $$ = $1;
	    }
	  else
	    $$ = tree_cons ($1, $3); }
    | IDENTIFIER '(' IDENTIFIER ',' CONSTANT ',' CONSTANT ')'
	{ /* if not "format(...)", then issue warning */
	  if (strcmp (IDENTIFIER_POINTER ($1), "format") != 0
	      || TREE_CODE ($5) != INTEGER_CST
	      || TREE_CODE ($7) != INTEGER_CST)
	    {
	      warning ("`%s' attribute directive ignored",
		       IDENTIFIER_POINTER ($1));
	      $$ = $1;
	    }
	  else
	    $$ = tree_cons ($1, tree_cons ($3, tree_cons ($5, $7))); }
    ;

init:
	expr_no_commas
	| '{' '}'
		{ $$ = build_nt (CONSTRUCTOR, NULL_TREE, NULL_TREE);
		  if (pedantic)
		    pedwarn ("ANSI C forbids empty initializer braces"); }
	| '{' initlist '}'
		{ $$ = build_nt (CONSTRUCTOR, NULL_TREE, nreverse ($2)); }
	| '{' initlist ',' '}'
		{ $$ = build_nt (CONSTRUCTOR, NULL_TREE, nreverse ($2)); }
	| error
		{ $$ = NULL_TREE; }
	;

/* This chain is built in reverse order,
   and put in forward order where initlist is used.  */
initlist:
	  init
		{ $$ = build_tree_list (NULL_TREE, $1); }
	| initlist ',' init
		{ $$ = tree_cons (NULL_TREE, $3, $1); }
	/* These are for labeled elements.  */
	| '[' expr_no_commas ']' init
		{ $$ = build_tree_list ($2, $4); }
	| initlist ',' '[' expr_no_commas ']' init