Share object across fuzz targets & increase build timeout

Author: edznux-dd

.gitlab/fuzzing/.gitlab-ci.yml

@@ -8,7 +8,7 @@ fuzz_infra:
   image: registry.ddbuild.io/images/docker:27.3.1
   tags: ["arch:amd64"]
   stage: fuzz
-  timeout: 30m
+  timeout: 1h30m
   allow_failure: true
   id_tokens:
     DDSIGN_ID_TOKEN:

build-logic/conventions/src/main/kotlin/com/datadoghq/native/fuzz/FuzzTargetsPlugin.kt

@@ -108,6 +108,26 @@ class FuzzTargetsPlugin : Plugin<Project> {
         val crashDir = extension.crashDir.get().asFile
         val duration = extension.duration.get()
 
+        // Profiler sources are identical for every fuzz target (same compiler args and
+        // includes), so compile them once and share the resulting objects across targets
+        // instead of recompiling the whole profiler per target.
+        val sharedObjDir = project.file("${project.layout.buildDirectory.get()}/obj/fuzz/_profiler")
+        val compileProfilerTask = project.tasks.register("compileFuzzProfilerSources", NativeCompileTask::class.java) {
+            onlyIf { hasFuzzer && !project.hasProperty("skip-tests") && !project.hasProperty("skip-native") && !project.hasProperty("skip-fuzz") }
+            group = "build"
+            description = "Compile the profiler sources shared by all fuzz targets"
+
+            this.compiler.set(compiler)
+            this.compilerArgs.set(compilerArgs)
+            sources.from(
+                extension.profilerSourceDir.map { dir ->
+                    project.fileTree(dir) { include("**/*.cpp") }
+                }
+            )
+            includes.from(includeFiles)
+            objectFileDir.set(sharedObjDir)
+        }
+
         // Discover and create tasks for each fuzz target
         if (fuzzSourceDir.exists()) {
             fuzzSourceDir.listFiles()?.filter { file -> file.name.endsWith(".cpp") }?.forEach { fuzzFile ->
@@ -119,34 +139,33 @@ class FuzzTargetsPlugin : Plugin<Project> {
                 val binary = project.file("$binDir/$fuzzName")
                 val targetCorpusDir = File(corpusBaseDir, fuzzName)
 
-                // Compile task
+                // Compile task - only compiles this target's own fuzz driver; profiler
+                // sources come from the shared compileFuzzProfilerSources task.
                 val compileTask = project.tasks.register("compileFuzz_$fuzzName", NativeCompileTask::class.java) {
                     onlyIf { hasFuzzer && !project.hasProperty("skip-tests") && !project.hasProperty("skip-native") && !project.hasProperty("skip-fuzz") }
                     group = "build"
                     description = "Compile the fuzz target $fuzzName"
 
                     this.compiler.set(compiler)
                     this.compilerArgs.set(compilerArgs)
-                    sources.from(
-                        extension.profilerSourceDir.map { dir ->
-                            project.fileTree(dir) { include("**/*.cpp") }
-                        },
-                        fuzzFile
-                    )
+                    sources.from(fuzzFile)
                     includes.from(includeFiles)
                     objectFileDir.set(objDir)
                 }
 
                 // Link task
                 val linkTask = project.tasks.register("linkFuzz_$fuzzName", NativeLinkExecutableTask::class.java) {
                     onlyIf { hasFuzzer && !project.hasProperty("skip-tests") && !project.hasProperty("skip-native") && !project.hasProperty("skip-fuzz") }
-                    dependsOn(compileTask)
+                    dependsOn(compileProfilerTask, compileTask)
                     group = "build"
                     description = "Link the fuzz target $fuzzName"
 
                     linker.set(compiler)
                     this.linkerArgs.set(linkerArgs)
-                    objectFiles.from(project.fileTree(objDir) { include("*.o") })
+                    objectFiles.from(
+                        project.fileTree(sharedObjDir) { include("*.o") },
+                        project.fileTree(objDir) { include("*.o") }
+                    )
                     outputFile.set(binary)
                 }