stfe(3) Library Functions Manual stfe(3)
stfe, st_filebegin, st_endallfiles, st_fileend, st_blockbegin, st_textblock, st_blockend, st_procend, st_procbegin, st_str_idn, st_sym_idn,
st_abs_ifd_index, st_fglobal_idn, st_psym_idn_offset, st_pdadd_idn - routines that provide a high-level interface to basic functions needed
to access and add to the symbol table
long st_filebegin (filename)
long st_endallfiles ()
long st_fileend (idn)
long st_blockbegin(iss, value, sc)
long st_procbegin (idn)
char *st_str_idn (idn)
char *st_sym_idn (idn, value, sc, st, index)
long st_abs_ifd_index (ifd, index)
long st_fglobal_idn (idn)
pSYMR st_psym_idn_offset (idn, offset)
long st_pdadd_idn (idn)
The stfe routines provide a high-level interface to the symbol table based on common needs of the compiler front-ends.
st_filebegin Takes a file name and calls st_fdadd (see If it is a new file, a symbol is added to the symbol table that for that file
or symbol, and the user supplied routine, st_feinit, is called. This allows special file parameters to be initialized.
For example, the C front-end adds basic type auxiliaries to each file's aux table so that all variables of that type
can refer to a single instance instead of making individual copies of them. The routine st_filebegin returns a dense
number that references the symbol added for this file. It tracks files as they appear in a CPP line directive with a
stack. It detects (from the order of the CPP directives) that a file ends and calls st_filend. If a file is closed
with a st_fileend, a new instance of the filename is created. For example, multiply included files.
st_fileend 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.
st_endallfiles Is called at the end of execution to close off all files that have not 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
st_blockbegin 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 occurs when the language block is detected and
the other stage occurs when 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 does not have content and st_textblock is not called,
the block's st_blockbegin and st_blockend do not produce block and end symbols.
If it is scInfo, st_blockbegin creates a begin block symbol in the symbol table and returns a dense number referencing it. The dense num-
ber 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 should not be called for language blocks when the front-end is not producing debugging symbols.
The st_blockend requires that blocks occur in a nested fashion. It retrieves the dense number for the most recently started block and cre-
ates 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 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.
st_procend 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.
st_str_idn Returns the string associated with symbol or external referenced by the dense number argument. If the symbol was anony-
mous (for example, there is not a symbol), a (char *), -1 is returned.
st_sym_idn 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.
st_fglobal_idn Returns a 1 if the symbol associated with the specified idn is non-static; otherwise, a 0 is returned.
st_abs_ifd_index 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
st_pdadd_idn 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), sym.h(5), stsupport.h(5)