Mercurial > hg > CbC > CbC_gcc
comparison gcc/LANGUAGES @ 0:a06113de4d67
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author | kent <kent@cr.ie.u-ryukyu.ac.jp> |
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date | Fri, 17 Jul 2009 14:47:48 +0900 |
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children | 77e2b8dfacca |
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1 Right now there is no documentation for the GCC tree -> rtl interfaces | |
2 (or more generally the interfaces for adding new languages). | |
3 | |
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 | |
7 changes we've made. | |
8 | |
9 2004-09-09: | |
10 In an effort to decrease execution time, single char tree code | |
11 classes were changed to enumerated values. | |
12 | |
13 Old way: | |
14 | |
15 DEFTREECODE (CLASS_METHOD_DECL, "class_method_decl", 'd', 0) | |
16 | |
17 New way: | |
18 | |
19 DEFTREECODE (CLASS_METHOD_DECL, "class_method_decl", tcc_declaration, 0) | |
20 | |
21 2001-02-26: | |
22 A DECL_INITIAL of NULL_TREE or error_mark_node in a VAR_DECL is no longer | |
23 taken to signify a tentative definition which should not be emitted until | |
24 end-of-file. Frontends which want that behavior should set | |
25 DECL_DEFER_OUTPUT before calling rest_of_decl_compilation. | |
26 | |
27 Feb 1, 1998: | |
28 | |
29 GCC used to store structure sizes & offsets to elements as bitsize | |
30 quantities. This causes problems because a structure can only be | |
31 (target memsize / 8) bytes long (this may effect arrays too). This | |
32 is particularly problematical on machines with small address spaces. | |
33 | |
34 So: | |
35 | |
36 All trees that represent sizes in bits should have a TREE_TYPE of | |
37 bitsizetype (rather than sizetype). | |
38 | |
39 Accordingly, when such values are computed / initialized, care has to | |
40 be takes to use / compute the proper type. | |
41 | |
42 When a size in bits is converted into a size in bytes, which is expressed | |
43 in trees, care should be taken to change the tree's type again to sizetype. | |
44 | |
45 ?? 1997: | |
46 | |
47 In an effort to decrease cache thrashing and useless loads we've changed the | |
48 third argument to the DEFTREECODE macro to be a single char. This will | |
49 affect languages that defined their own tree codes (usually in a .def file). | |
50 | |
51 Old way: | |
52 | |
53 DEFTREECODE (CLASS_METHOD_DECL, "class_method_decl", "d", 0) | |
54 | |
55 New way: | |
56 | |
57 DEFTREECODE (CLASS_METHOD_DECL, "class_method_decl", 'd', 0) |