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Section: C Library Functions (3)
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stfe - Routines that provide a high-level interface to basic functions needed to access and add to the symbol table  


#include <syms.h>

long st_filebegin (filename, lang, merge, glevel)
char *filename;
long lang;
long merge;
long glevel;

long st_endallfiles ()

long st_fileend (idn)
long idn;

long st_blockbegin(iss, value, sc)
long iss;
long value;
long sc;

long st_textblock()

long st_blockend(size)
long size;

long st_procend(idn)
long idn

long st_procbegin (idn)
long idn;

char *st_str_idn (idn)
long idn;

char *st_sym_idn (idn, value, sc, st, index)
long idn;
long *value;
long *sc;
long *st;
long *index;

long st_abs_ifd_index (ifd, index)
long ifd;
long index;

long st_fglobal_idn (idn)
long idn;

pSYMR st_psym_idn_offset (idn, offset)
long idn;
long offset;

long st_pdadd_idn (idn)
long idn;


The stfe routines provide a high-level interface to the symbol table based on common needs of the compiler front-ends. Should be called upon encountering each cpp directive in the front end. It calls st_fileadd to add symbols and will find the appropriate open file or start a new file. It takes a filename, language constant (see symconst.h), a merge flag (0 or 1) and the -g level constant (see symconst.h). It returns a dense number pointing to the file symbol to be used in line number directives. Requires the dense number from the corresponding st_filebegin call for the file in question. It then generates an end symbol and patches the references so that the index field of the begin file points to that of one beyond the end file. The end file points to the begin file. Is called at the end of execution to close off all files that haven't been ended by previous calls to st_filebegin. CPP directives might not reflect the return to the original source file; therefore, this routine can possibly close many files. Supports both language blocks (for example, C's left curly brace blocks), beginning of structures, and unions. If the storage class is scText, it is the former; if it is scInfo, it is one of the latter. The iss (index into string space) specifies the name of the structure/etc, if any.

If the storage class is scText, we must check the result of st_blockbegin. It returns a dense number for outer blocks and a zero for nested blocks. The non-zero block number should be used in the BGNB ucode. Users of languages without nested blocks that provide variable declarations can ignore the rest of this paragraph. Nested blocks are two-staged: one stage happens when we detect the language block and the other stage happens when we know the block has content. If the block has content (for example, local variables), the front-end must call st_textblock to get a non-zero dense number for the block's BGNB ucode. If the block has no content and st_textblock is not called, the block's st_blockbegin and st_blockend do not produce block and end symbols.
If the storage class is scInfo, st_blockbegin creates a begin block symbol in the symbol table and returns a dense number referencing it. The dense number is necessary to build the auxiliary required to reference the structure/etc. It goes in the aux after the TIR along with a file index. This dense number is also noted in a stack of blocks used by st_blockend.
The st_blockbegin routine should not be called for language blocks when the front-end is not producing debugging symbols. Requires that blocks occur in a nested fashion. It retrieves the dense number for the most recently started block and creates a corresponding end symbol. As in fileend, both the begin and end symbol index fields point at the other end's symbol. If the symbol ends a structure/etc., as determined by the storage class of the begin symbol, the size parameter is assigned to the begin symbol's value field. It is usually the size of the structure or max value of a enum. We only know it at this point. The dense number of the end symbol is returned so that the ucode ENDB can be use it. If it is an ignored text block, the dense number is zero and no ENDB should be generated.
In general, defined external procedures or functions appear in the symbols table and the externals table. The external table definition must occur first through the use of a st_extadd. After that definition, st_procbegin can be called with a dense number referring to the external symbol for that procedure. It checks to be sure we have a defined procedure (by checking the storage class). It adds a procedure symbol to the symbol table. The external's index should point at its auxiliary data type information (or if debugging is off, indexNil). This index is copied into the regular symbol's index field or a copy of its type is generated (if the external is in a different file than the regular symbol). Next, we put the index to symbol in the external's index field. The external's dense number is used as a block number in ucodes referencing it and is used to add a procedure when in the st_pdadd_idn. Creates an end symbol and fixes the indices as in blockend and fileend, except that the end procedure reference is kept in the begin procedure's aux rather than in the index field (because the begin procedure has a type as well as an end reference). This must be called with the dense number of the procedure's external symbol as an argument and returns the dense number of the end symbol to be used in the END ucode. Returns the string associated with symbol or external referenced by the dense number argument. If the symbol was anonymous (for example, there was no symbol) a (char *), -1 is returned. Returns the same result as st_str_idn, except that the rest of the fields of the symbol specified by the idn are returned in the arguments. Returns a 1 if the symbol associated with the specified idn is non-static; otherwise, a 0 is returned. Returns the absolute offset for a dense number. If the symbol is global, the global's index is returned. If the symbol occurred in a file, the sum of all symbols in files occurring before that file and the symbol's index within the file is returned. Adds an entry to the procedure table for the st_proc entry generated by procbegin. This should be called when the front-end generates code for the procedure in question.


stcu(3), stfd(3) delim off




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Time: 02:41:24 GMT, October 02, 2010