Standalone support for AOT as dylibs on Fuchsia.

BUG=
R=zra@google.com

Review-Url: https://codereview.chromium.org/2774993002 .

runtime/bin/BUILD.gn

@@ -4,6 +4,7 @@
 
 import("gypi_contents.gni")
 import("../runtime_args.gni")
+import("../../build/compiled_action.gni")
 
 # Generate a resources.cc file for the service isolate without Observatory.
 action("gen_resources_cc") {
@@ -691,14 +692,47 @@ dart_executable("dart_bootstrap") {
 }
 
 if (defined(is_fuchsia) && is_fuchsia) {
+  hello_fuchsia_source = rebase_path("../tests/vm/dart/hello_fuchsia_test.dart")
+
   copy("hello_fuchsia") {
     sources = [
-      "../tests/vm/dart/hello_fuchsia_test.dart",
+      hello_fuchsia_source,
     ]
     outputs = [
       "$root_out_dir/hello_fuchsia.dart",
     ]
   }
+
+  hello_fuchsia_assembly = "$target_gen_dir/hello_fuchsia.S"
+
+  compiled_action("hello_fuchsia_assembly") {
+    inputs = [
+      hello_fuchsia_source,
+    ]
+    outputs = [
+      hello_fuchsia_assembly,
+    ]
+    tool = ":dart_bootstrap"
+    args = [
+      "--snapshot-kind=app-aot",
+      "--snapshot=" + rebase_path(hello_fuchsia_assembly),
+      hello_fuchsia_source,
+    ]
+  }
+
+  shared_library("hello_fuchsia_dylib") {
+    deps = [
+      ":hello_fuchsia_assembly",
+    ]
+    sources = [
+      hello_fuchsia_assembly,
+    ]
+    cflags = [
+      "-nostdlib",
+      "-nostartfiles",
+    ]
+    output_name = "hello_fuchsia"
+  }
 }
 
 executable("process_test") {

runtime/bin/extensions_fuchsia.cc

@@ -6,7 +6,10 @@
 #if defined(HOST_OS_FUCHSIA)
 
 #include "bin/extensions.h"
-#include <dlfcn.h>  // NOLINT
+
+#include <dlfcn.h>
+#include <launchpad/vmo.h>
+#include <magenta/dlfcn.h>
 
 #include "platform/assert.h"
 
@@ -20,7 +23,11 @@ const char* kIsolateSnapshotInstructionsSymbolName =
     "_kDartIsolateSnapshotInstructions";
 
 void* Extensions::LoadExtensionLibrary(const char* library_file) {
-  return dlopen(library_file, RTLD_LAZY);
+  mx_handle_t vmo = launchpad_vmo_from_file(library_file);
+  if (vmo <= 0) {
+    return NULL;
+  }
+  return dlopen_vmo(vmo, RTLD_LAZY);
 }
 
 

runtime/vm/dart_api_impl.cc

@@ -6703,6 +6703,9 @@ Dart_CreateAppAOTSnapshotAsBlobs(uint8_t** vm_snapshot_data_buffer,
 #elif !defined(DART_PRECOMPILER)
   return Api::NewError(
       "This VM was built without support for AOT compilation.");
+#elif defined(TARGET_OS_FUCHSIA)
+  return Api::NewError(
+      "AOT as blobs is not supported on Fuchsia; use dylibs instead.");
 #else
   API_TIMELINE_DURATION;
   DARTSCOPE(Thread::Current());