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comparison gcc/go/gofrontend/README @ 145:1830386684a0

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gcc-9.2.0
author anatofuz
date Thu, 13 Feb 2020 11:34:05 +0900
parents 04ced10e8804
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1 See ../README. 1 See ../README.
2 2
3 The frontend is written in C++. 3 The frontend is written in C++. It can only be used in conjunction
4 with a full compiler backend. Currently the backend interface has
5 been implemented with GCC (known as gccgo) and with LLVM (known as
6 GoLLVM).
4 7
5 The frontend lexes and parses the input into an IR specific to this 8 The frontend lexes and parses the input into an IR specific to this
6 frontend known as gogo. It then runs a series of passes over the 9 frontend known as gogo. It then runs a series of passes over the
7 code. 10 code.
8 11
9 Finally it converts gogo to gcc's GENERIC. A goal is to move the gcc 12 Finally it converts gogo to the backend IR. This is done via the
10 support code into a gcc-interface subdirectory. The gcc code will be 13 interface described in backend.h. The backend must implement that
11 put under the GPL. The rest of the frontend will not include any gcc 14 interface. When used with GCC, the interface is implemented in
12 header files. 15 gcc/go/go-gcc.cc.
13 16
14 Issues to be faced in this transition: 17 Source locations are represented using the interface described in
18 go-linemap.h. The backend is expected to provide a header file
19 go-location.h that defines a Location type.
15 20
16 * Representation of source locations. 21 The frontend does not start by itself. It expects something to call
17 + Currently the frontend uses gcc's source_location codes, using the 22 go_create_gogo passing in a Backend and a Linemap, as well as other
18 interface in libcpp/line-map.h. 23 options. Then it expects something to call go_parse_input_files
24 passing in the input files. Finally, a call to go_write_globals will
25 cause all global definitions to be written out via the Backend
26 interface.
19 27
20 * Handling of error messages. 28 The backend is expected to provide the functions defined at the
21 + Currently the frontend uses gcc's error_at and warning_at 29 bottom of go-diagnostics.h: go_be_error_at, etc. These will be used
22 functions. 30 for error messages.
23 + Currently the frontend uses gcc's diagnostic formatter, using
24 features such as %<%> for appropriate quoting.
25 + Localization may be an issue.
26 31
27 This compiler works, but the code is a work in progress. Notably, the 32 This compiler works, but the code is a work in progress. The frontend
28 support for garbage collection is ineffective and needs a complete 33 pays little attention to its memory usage and rarely frees any memory.
29 rethinking. The frontend pays little attention to its memory usage 34 The code could use a general cleanup which we have not had time to do.
30 and rarely frees any memory. The code could use a general cleanup
31 which we have not had time to do.
32 35
33 Contributing 36 Contributing
34 ============= 37 =============
35 38
36 To contribute patches to the files in this directory, please see 39 To contribute patches to the files in this directory, please see
37 http://golang.org/doc/gccgo_contribute.html . 40 https://golang.org/doc/gccgo_contribute.html .
38 41
39 The master copy of these files is hosted at 42 The master copy of these files is hosted at
40 http://code.google.com/p/gofrontend . Changes to these files require 43 https://go.googlesource.com/gofrontend . There is a mirror at
44 https://github.com/golang/gofrontend . Changes to these files require
41 signing a Google contributor license agreement. If you are the 45 signing a Google contributor license agreement. If you are the
42 copyright holder, you will need to agree to the individual contributor 46 copyright holder, you will need to agree to the individual contributor
43 license agreement at 47 https://cla.developers.google.com/about/google-individual . This
44 http://code.google.com/legal/individual-cla-v1.0.html. This agreement 48 agreement can be completed online.
45 can be completed online.
46 49
47 If your organization is the copyright holder, the organization will 50 If your organization is the copyright holder, the organization will
48 need to agree to the corporate contributor license agreement at 51 need to agree to the corporate contributor license agreement at
49 http://code.google.com/legal/corporate-cla-v1.0.html. 52 https://cla.developers.google.com/about/google-corporate .
50 53
51 If the copyright holder for your code has already completed the 54 If the copyright holder for your code has already completed the
52 agreement in connection with another Google open source project, it 55 agreement in connection with another Google open source project, it
53 does not need to be completed again. 56 does not need to be completed again.