Add support for optimized and debug builds (#103)

Co-authored-by: Peter McEvoy <[email protected]>
(cherry picked from commit 90cc9ca)

.bazelrc

@@ -14,12 +14,15 @@ build --incompatible_enable_cc_toolchain_resolution
 build --@io_bazel_rules_docker//transitions:enable=false
 
 # Add aliases for compiler version build settings.
-build --flag_alias=aarch64_linux_gnu_gcc_version=//:aarch64_linux_gnu_gcc_version
 build --flag_alias=clang_version=//:clang_version
 build --flag_alias=gcc_version=//:gcc_version
 
-# Add alias for Docker image tag.
-build --flag_alias=image_tag=//:image_tag
+# Always include source-level debug info.
+build --copt='-g'
+build --strip=never
+
+# Use -O3 as the default optimization level.
+build --copt='-O3'
 
 # Any personal configuration should go in .user.bazelrc.
 try-import %workspace%/.user.bazelrc

INSTALL.md

@@ -64,6 +64,15 @@ platform in the build command:
 $ bazel build --platforms=//:<target-platform> //pkg/...
 ```
 
+The default optimization level is `-O3`, but if you want to specify a different
+optimization level, use [`--copt`][copt]:
+```console
+$ bazel build --copt='-O0' :urbit
+```
+
+Note [`--copt`][copt] can be used to specify any C compiler options, not just
+optimization levels.
+
 ## Test Commands
 
 You can build and run unit tests only on native builds. If you have a native
@@ -78,6 +87,21 @@ If you want to run a specific test, say
 $ bazel test //pkg/noun:hashtable_tests
 ```
 
+## Build Configuration File
+
+Any options you specify at the command line can instead be specified in
+`.user.bazelrc` if you find yourself using the same options over and over. This
+file is not tracked by `git`, so whatever you add to it will not affect anyone
+else. As an example, if you want to change the optimization level but don't want
+type `--copt='-O0'` each time, you can do the following:
+```console
+$ echo "build --copt='-O0'" >> .user.bazelrc
+$ bazel build :urbit
+```
+
+For more information on Bazel configuration files, consult the
+[Bazel docs][bazel-config].
+
 ## Common Issues
 
 If `bazel build` or `bazel test` generates an `undeclared inclusion(s) in rule`
@@ -91,5 +115,7 @@ pass `--clang_version="<version_string>"` to the failing command.
       `BUILD.bazel` files in [`pkg/`](pkg).
 
 [bazel]: https://bazel.build
+[bazel-config]: https://bazel.build/run/bazelrc
+[copt]: https://bazel.build/docs/user-manual#copt
 [glibc]: https://www.gnu.org/software/libc
 [musl libc]: https://musl.libc.org