cef3a56049
Adds a section to `AddingACompiler.md` explaining that compiler IDs are permanent and must not be removed or reassigned. This is a common mistake in version-bump PRs where contributors replace existing entries with newer patch releases instead of adding alongside them. The new section covers: - Why IDs must be stable (shortlinks, saved sessions, embeds) - The correct approach when adding newer versions (add, don't replace) - Using `alias` as a fallback when a compiler genuinely can't be kept - The same rule applying to infra install targets - The rare exception for lesser-used languages with involved maintainers 🤖 Generated by LLM (Claude, via OpenClaw) Co-authored-by: mattgodbolt-molty <mattgodbolt-molty@users.noreply.github.com>
How do I ?
This is a how-to guide for the user-interface presented by Compiler Explorer. This doesn't cover the details of how to set up or modify Compiler Explorer for your own needs. For that, please check the documents which already cover topics like:
- Adding a language
- Adding a compiler
- Adding a library
- Adding a tool
- and many more at compiler-explorer/docs
Fast links:
Change the assembly syntax from Intel
The option to switch assembly from Intel to AT&T syntax is present in the Output option of each compiler. If enough
space is not present, the option also presents itself as the gear symbol (⚙)
Compare the time taken by compilation and networking
This is the symbol that looks like a bar graph (📊). If your compilations are taking long, you can use this to check the time taken by:
- Networking, JavaScript, waiting for events, etc.
- Checking the cache and retrieving from it on a cache-hit
- Compilation (on force compilation or cache-miss)
- Parsing the generated assembly before presenting it
View intermediate information provided by the compilers
Though both GCC and Clang create supplementary outputs along with assembly (shown by default), and an executable (created if an executor has been added), the exact nature of the outputs and their formats differ between the compilers.
GCC allows the Tree, IPA, RTL and graph outputs, while Clang allows optimization, AST, IR and graph outputs. Some outputs (e.g. RTL or graph) also have a rich set of options in the UI to enable focussing on a particular function or compiler stage.