98 lines
4.0 KiB
Plaintext
98 lines
4.0 KiB
Plaintext
Right now there is no documentation for the GCC tree -> rtl interfaces
|
|
(or more generally the interfaces for adding new languages).
|
|
|
|
Such documentation would be of great benefit to the project. Until such
|
|
time as we can formally start documenting the interface this file will
|
|
serve as a repository for information on these interface and any incompatable
|
|
changes we've made.
|
|
|
|
2001-02-26:
|
|
A DECL_INITIAL of NULL_TREE or error_mark_node in a VAR_DECL is no longer
|
|
taken to signify a tentative definition which should not be emitted until
|
|
end-of-file. Frontends which want that behavior should set
|
|
DECL_DEFER_OUTPUT before calling rest_of_decl_compilation.
|
|
|
|
Aug 31, 1998:
|
|
The interface to HANDLE_PRAGMA has changed. It now takes three arguments.
|
|
The first two are pointers to functions that should be used to read characters
|
|
from the input stream, and to push them back into the input stream respectively.
|
|
The third argument is a pointer to a null terminate string which is the first
|
|
word after #pragma. The expression supplied by HANDLE_PRAGMA should return
|
|
non-zero if it parsed and implemented the pragma. Otherwise it should return
|
|
zero, and leave the input stream as it was before the expression was evaluated.
|
|
|
|
A new back-end definable macro has been added: INSERT_ATTRIBUTES. This macro
|
|
allows backend to add attributes to decls as they are created.
|
|
|
|
Jun 10, 1998:
|
|
The interface to lang_decode_option has changed. It now uses and argc/argv
|
|
interface to allow for options that use more than one input string. The new
|
|
declaration is: int lang_decode_option (int argc, char** argv). It now
|
|
returns the number of input strings processed, or 0 if the option is
|
|
unknown.
|
|
|
|
Jun 7, 1998:
|
|
Front-ends must now define lang_init_options. It is safe for this
|
|
function to do nothing. See c-lang.c.
|
|
|
|
Apr 21, 1998:
|
|
Front ends which link with c-common or other files from the C/C++
|
|
front-ends may need to handle TI types. Look for references to
|
|
[unsigned]int_DI_type_node in your front end. If you have references
|
|
to these variables, you'll need up update the front end.
|
|
|
|
To update the front end you must mirror all the code which currently
|
|
deals with intDI_type_node to also handle intTI_type_node.
|
|
|
|
|
|
Apr 7, 1998:
|
|
The interface between toplev.c and the language front ends for opening the
|
|
source file has changed:
|
|
|
|
o init_lex() has been renamed to init_parse (char *filename) where filename
|
|
is the name of the source file.
|
|
o The code in toplev.c which opened the source file should be moved to
|
|
the new init_parse function.
|
|
o toplev.c now calls finish_parse() instead of closing the source file
|
|
using fclose(). This should now be done in finish_parse, if necessary.
|
|
|
|
Apr 1, 1998:
|
|
Front-ends must now define lang_print_xnode. It is safe for this
|
|
function to do nothing. See c-lang.c.
|
|
|
|
Feb 1, 1998:
|
|
|
|
GCC used to store structure sizes & offsets to elements as bitsize
|
|
quantities. This causes problems because a structure can only be
|
|
(target memsize / 8) bytes long (this may effect arrays too). This
|
|
is particularly problematical on machines with small address spaces.
|
|
|
|
So:
|
|
|
|
All trees that represent sizes in bits should have a TREE_TYPE of
|
|
bitsizetype (rather than sizetype).
|
|
|
|
Accordingly, when such values are computed / initialized, care has to
|
|
be takes to use / compute the proper type.
|
|
|
|
When a size in bits is converted into a size in bytes, which is expressed
|
|
in trees, care should be taken to change the tree's type again to sizetype.
|
|
|
|
We've updated C, C++, Fortran & Objective-C to work with the new
|
|
scheme. Other languages will need to be updated accordingly.
|
|
Contact amylaar@cygnus.com for additional information.
|
|
|
|
?? 1997:
|
|
|
|
In an effort to decrease cache thrashing and useless loads we've changed the
|
|
third argument to the DEFTREECODE macro to be a single char. This will
|
|
affect languages that defined their own tree codes (usually in a .def file).
|
|
|
|
Old way:
|
|
|
|
DEFTREECODE (CLASS_METHOD_DECL, "class_method_decl", "d", 0)
|
|
|
|
New way:
|
|
|
|
DEFTREECODE (CLASS_METHOD_DECL, "class_method_decl", 'd', 0)
|