Swift ideal integration (#6312)

* Helper flags for swift compilation

* Documentation for swift project integration

* Adds swift to the languages with coverage

* Only thread sanitizer is supported

* Fixes swift coverage target compilation

* fixup flags facotring

* swift: run on new ubuntu

* fixup

* swift: right copy for symbolizer

1 files changed, 78 insertions, 0 deletions

diff --git a/docs/getting-started/new-project-guide/swift.md b/docs/getting-started/new-project-guide/swift.md
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+---
+layout: default
+title: Integrating a Swift project
+parent: Setting up a new project
+grand_parent: Getting started
+nav_order: 1
+permalink: /getting-started/new-project-guide/swift/
+---
+
+# Integrating a Swift project
+{: .no_toc}
+
+- TOC
+{:toc}
+---
+
+The process of integrating a project written in Swift with OSS-Fuzz is very similar
+to the general
+[Setting up a new project]({{ site.baseurl }}/getting-started/new-project-guide/)
+process. The key specifics of integrating a Swift project are outlined below.
+
+## Project files
+
+First, you need to write a Swift fuzz target that accepts a stream of bytes and
+calls the program API with that. This fuzz target should reside in your project
+repository.
+
+The structure of the project directory in OSS-Fuzz repository doesn't differ for
+projects written in Swift. The project files have the following Swift specific
+aspects.
+
+### project.yaml
+
+The `language` attribute must be specified.
+
+```yaml
+language: swift
+```
+
+The only supported fuzzing engine is `libfuzzer`
+
+The supported sanitizers are and `address`, `thread`
+
+[Example](https://github.com/google/oss-fuzz/blob/2a15c3c88b21f4f1be2a7ff115f72bd7a08e34ac/projects/swift-nio/project.yaml#L9):
+
+```yaml
+fuzzing_engines:
+  - libfuzzer
+sanitizers:
+  - address
+  - thread
+```
+
+### Dockerfile
+
+The Dockerfile should start by `FROM gcr.io/oss-fuzz-base/base-builder-swift`
+instead of using the simple base-builder
+
+### build.sh
+
+A `precompile_swift` generates an environment variable `SWIFTFLAGS`
+This can then be used in the building command such as `swift build -c release $SWIFTFLAGS`
+
+
+A usage example from swift-protobuf project is
+
+```sh
+. precompile_swift
+# build project
+cd FuzzTesting
+swift build -c debug $SWIFTFLAGS
+
+(
+cd .build/debug/
+find . -maxdepth 1 -type f -name "*Fuzzer" -executable | while read i; do cp $i $OUT/"$i"-debug; done
+)
+
+```