Add WASI as a supported target for sanitizers

We are adding support for sanitizers on WASI targets. This commit adds driver support by unblocking hard-coded checks and forwarding sanitizer flags to clang linker driver.

Author: kateinoigakukun

Sources/SwiftDriver/Driver/Driver.swift

@@ -2751,7 +2751,7 @@ extension Driver {
  }
 
  // Check that we're one of the known supported targets for sanitizers.
- if !(targetTriple.isWindows || targetTriple.isDarwin || targetTriple.os == .linux) {
+ if !(targetTriple.isWindows || targetTriple.isDarwin || targetTriple.os == .linux || targetTriple.os == .wasi) {
  diagnosticEngine.emit(
  .error_unsupported_opt_for_target(
  arg: "-sanitize=",

Sources/SwiftDriver/Jobs/WebAssemblyToolchain+LinkerSupport.swift

@@ -165,8 +165,12 @@ extension WebAssemblyToolchain {
 
  // Delegate to Clang for sanitizers. It will figure out the correct linker
  // options.
- guard sanitizers.isEmpty else {
- throw Error.sanitizersUnsupportedForTarget(targetTriple.triple)
+ if linkerOutputType == .executable && !sanitizers.isEmpty {
+ let sanitizerNames = sanitizers
+ .map { $0.rawValue }
+ .sorted() // Sort so we get a stable, testable order
+ .joined(separator: ",")
+ commandLine.appendFlag("-fsanitize=\(sanitizerNames)")
  }
 
  if parsedOptions.hasArgument(.profileGenerate) {

Sources/SwiftDriver/Toolchains/WebAssemblyToolchain.swift

@@ -146,7 +146,7 @@ public final class WebAssemblyToolchain: Toolchain {
  targetTriple: Triple,
  isShared: Bool
  ) throws -> String {
- throw Error.sanitizersUnsupportedForTarget(targetTriple.triple)
+ return "libclang_rt.\(sanitizer.libraryName)-\(targetTriple.archName).a"
  }
 
  public func platformSpecificInterpreterEnvironmentVariables(env: [String : String],