README.md

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Compiler Explorer
------------

Compiler Explorer is an interactive compiler. The left-hand pane shows editable C, C++, Rust, Go, D, Haskell, Swift and Pascal code.
The right, the assembly output of having compiled the code with a given compiler and settings. Multiple compilers are supported, and
the UI layout is configurable (the [Golden Layout](https://www.golden-layout.com/) library is used for this).
There is also an ispc compiler for a C variant with extensions for SPMD.

Try out at [godbolt.org](https://godbolt.org)

You can support [this project on Patreon](https://patreon.com/mattgodbolt).

##### Contact us

For general discussion, feel free to join the mailing list: https://groups.google.com/forum/#!forum/compiler-explorer-discussion or the cpplang slack https://cpplang.now.sh/ channel `#compiler_explorer`.

If you are interested in developing, or want to see the discussions between existing developers, feel free to join the mailing list at https://groups.google.com/forum/#!forum/compiler-explorer-development or the cpplang slack https://cpplang.now.sh/ channel `#ce_implementation`.

### Developing or running a local instance

Compiler Explorer is written in node.js.

Assuming you have a compatible version of `node` installed, simply running `make` ought to get you up and running with an Explorer
running on port 10240 on your local machine: http://localhost:10240/. Currently Compiler Explorer requires `node` v8 installed, either on the path or at `NODE_PATH` (an environment variable or `make` parameter).

The `Makefile` will automatically install all the third party libraries needed to run; using `npm` to install server-side
components and `bower` to install all the client-facing libraries.

If you want to point it at your own GCC or similar binaries, either edit the `etc/config/compiler-explorer.defaults.properties` or else make a new one with the name
`compiler-explorer.local.properties`. `*.local.properties` files have the highest priority when loading properties.

The config system leaves a lot to be desired, I'm working on porting [CCS](https://github.com/hellige/ccs-cpp) to javascript and then something more rational can be used.

Feel free to raise an issue on [github](https://github.com/mattgodbolt/compiler-explorer/issues) or
[email me directly](mailto:matt@godbolt.org) for more help.

There's now a [Road map](Roadmap.md) that gives a little insight into future plans for Compiler Explorer.

### RESTful API

There's a simple restful API that can be used to do compiles to asm and to list compilers. In general
all handlers live in `/api/*` endpoints, and will accept JSON or text in POSTs, and will return text responses
or JSON responses depending on the request's `Accept` header.

At a later date there may be some form of rate-limiting: currently requests will be queued and dealt with
exactly like interactive requests on the main site. Authentication might be required at some point in the
future (for the main Compiler Explorer site anyway).

The following endpoints are defined:

#### `GET /api/languages` - return a list of languages

Returns a list of the currently supported languages, as pairs of languages IDs and their names.

#### `GET /api/compilers` - return a list of compilers

Returns a list of compilers. In text form, there's a simple formatting of the ID of the compiler, its
description and its languge ID. In JSON, all the information is returned as an array of compilers, with the `id` key being the
primary identifier of each compiler.


#### `GET /api/compilers/<language-id>` - return a list of compilers with mstching language

Returns a list of compilers for the provided language id. In text form, there's a simple formatting of the ID of the compiler, its
description and its languge ID. In JSON, all the information is returned as an array of compilers, with the `id` key being the
primary identifier of each compiler.

#### `POST /api/compiler/<compiler-id>/compile` - perform a compilation

To specify a compilation request as a JSON document, post it as the appropriate type and send an object of
the form: 
```JSON
{
    "source": "Source to compile",
    "options": {
        "userArguments": "Compiler flags",
        "compilerOptions": {},
        "filters": {
            "filter": true
        }
    }
}
``` 
The filters are an JSON object with true/false. If not supplied, defaults are used. If supplied, the
filters are used as-is. The `compilerOptions` is used to pass extra arguments to the back end, and is probably
not useful for most REST users. 

A text compilation request has the source as the body of the post, and uses query parameters to pass the
options and filters. Filters are supplied as a comma-separated string. Use the query parameter `filters=XX`
to set the filters directly, else `addFilters=XX` to add a filter to defaults, or `removeFilters` to remove from defaults. Compiler parameters should be passed as `options=-O2` and default to empty.

Filters include `binary`, `labels`, `intel`, `comments` and `directives` and correspond to the UI buttons on
the HTML version.

The text request is designed for simplicity for command-line clients like `curl`:

```bash
$ curl 'https://gcc.godbolt.org/api/compiler/g63/compile?options=-Wall' --data-binary 'int foo() { return 1; }'
# Compilation provided by Compiler Explorer at gcc.godbolt.org
foo():
        push    rbp
        mov     rbp, rsp
        mov     eax, 1
        pop     rbp
        ret
```

If JSON is present in the request's `Accept` header, the compilation results are of the form:

Optional values are marked with a '**'

```javascript
{
  "code": 0 if successful, else compiler return code,
  "stdout": [
            {
              "text": Output,
              ** "tag": {
                          "line": Source line,
                          "text": Parsed error for that line
                 }
            },
            ...
  ],
  "stderr": (format is similar to that of stdout),
  "asm": [
         {
           "text": Assembly text,
           "source": {file: null for user input, else path, line: number} or null if none
         },
         ...
  ],
  "okToCache": true if output could be locally cached else false,
  ** "optOutput" : {
                     "displayString" : String displayed in output,
                     "Pass" : [ Missed | Passed | Analysis ] (Specifies the type of optimisation output),
                     "Name" : Name of the output (mostly represents the reason for the output),
                     "DebugLoc" : {
                        "File": Name of file,
                        "Line": Line number,
                        "Column": Column number in line
                     },
                     "Function": Name of function for which optimisation output is provided,
                     "Args": Array of objects representing the arguments that the optimiser used when trying to optimise
     }
}
```

### Credits

Compiler Explorer is maintained by [Matt Godbolt](http://xania.org), [Rubén Rincón](https://github.com/RabsRincon) and [Simon Brand](https://blog.tartanllama.xyz/).
- [Gabriel Devillers](https://github.com/voxelf) - Initial multiple compilers and difference view (while working for [Kalray](http://www.kalrayinc.com/)).
- [Jared Wyles](https://github.com/jaredwy) - Clang OPT Output view and maintenance
- [Johan Engelen](https://github.com/JohanEngelen) - D support and its maintenance
- [Chedy Najjar](https://github.com/CppChedy) - CFG View and maintenance
- [Patrick Quist](https://github.com/partouf) - Pascal support
- [Joshua Sheard](https://github.com/jsheard) - ISPC support
- [Marc Poulhiès](https://github.com/dkm) - GCC Dumps view
- [Andrew Pardoe](https://github.com/AndrewPardoe) - WSL-CL support