Swift: DX changes based on my new setup experience

Author: d10c

swift/README.md

@@ -1,8 +1,10 @@
+# Swift on CodeQL
+
 ## Warning
 
-The Swift codeql package is an experimental and unsupported work in progress.
+The Swift CodeQL package is an experimental and unsupported work in progress.
 
-## Usage
+## Building the Swift extractor
 
 First ensure you have Bazel installed, for example with
 
@@ -13,16 +15,17 @@ brew install bazelisk
 then from the `ql` directory run
 
 ```bash
-bazel run //swift:create-extractor-pack
+bazel run //swift:create-extractor-pack    # --cpu=darwin_x86_64 # Uncomment on Arm-based Macs
 ```
 
 which will install `swift/extractor-pack`.
 
-Using `--search-path=swift/extractor-pack` will then pick up the Swift extractor. You can also use
-`--search-path=.`, as the extractor pack is mentioned in the root `codeql-workspace.yml`.
-
 Notice you can run `bazel run :create-extractor-pack` if you already are in the `swift` directory.
 
+Using `codeql ... --search-path=swift/extractor-pack` will then pick up the Swift extractor. You can also use
+`--search-path=.`, as the extractor pack is mentioned in the root `codeql-workspace.yml`. Alternatively, you can
+set up the search path in [the per-user CodeQL configuration file](https://codeql.github.com/docs/codeql-cli/specifying-command-options-in-a-codeql-configuration-file/#using-a-codeql-configuration-file).
+
 ## Code generation
 
 Run

swift/tools/qltest.sh

@@ -10,5 +10,7 @@ for src in *.swift; do
   opts=(-sdk "$CODEQL_EXTRACTOR_SWIFT_ROOT/qltest/$CODEQL_PLATFORM/sdk" -c -primary-file $src)
   opts+=($(sed -n '1 s=//codeql-extractor-options:==p' $src))
   echo -e "calling extractor with flags: ${opts[@]}\n" >> $QLTEST_LOG
-  "$CODEQL_EXTRACTOR_SWIFT_ROOT/tools/$CODEQL_PLATFORM/extractor" "${opts[@]}" >> $QLTEST_LOG 2>&1
+  "$CODEQL_EXTRACTOR_SWIFT_ROOT/tools/$CODEQL_PLATFORM/extractor" "${opts[@]}" >> $QLTEST_LOG 2>&1 || FAILED=1
 done
+
+[ -z "$FAILED" ] || cat "$QLTEST_LOG" # Show compiler errors on extraction failure