46 lines
1.7 KiB
Plaintext
46 lines
1.7 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.
|
|
|
|
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.
|
|
|
|
?? 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)
|