1 Right now there is no documentation for the GCC tree -> rtl interfaces
2 (or more generally the interfaces for adding new languages).
4 Such documentation would be of great benefit to the project. Until such
5 time as we can formally start documenting the interface this file will
6 serve as a repository for information on these interface and any incompatable
12 GCC used to store structure sizes & offsets to elements as bitsize
13 quantities. This causes problems because a structure can only be
14 (target memsize / 8) bytes long (this may effect arrays too). This
15 is particularly problematical on machines with small address spaces.
19 All trees that represent sizes in bits should have a TREE_TYPE of
20 bitsizetype (rather than sizetype).
22 Accordingly, when such values are computed / initialized, care has to
23 be takes to use / compute the proper type.
25 When a size in bits is converted into a size in bytes, which is expressed
26 in trees, care should be taken to change the tree's type again to sizetype.
28 We've updated C, C++, Fortran & Objective-C to work with the new
29 scheme. Other languages will need to be updated accordingly.
30 Contact amylaar@cygnus.com for additional information.
34 In an effort to decrease cache thrashing and useless loads we've changed the
35 third argument to the DEFTREECODE macro to be a single char. This will
36 effect languages that defined their own tree codes (usually in a .def file).
40 DEFTREECODE (CLASS_METHOD_DECL, "class_method_decl", "d", 0)
44 DEFTREECODE (CLASS_METHOD_DECL, "class_method_decl", 'd', 0)