From eb1ca45df7676fff92f5b13627ab9c0ccc29c292 Mon Sep 17 00:00:00 2001
From: Austin Eng <enga@chromium.org>
Date: Sat, 25 Jan 2020 02:14:39 +0000
Subject: [PATCH] Fix Vulkan fuzzer on mac_libfuzzer_chrome_asan

This commit fixes two problems:
1) It includes testing/libfuzzer/libfuzzer_exports.h which exports
   the LLVMFuzzerInitialize symbol. On Mac, not doing so causes it
   to be removed by the linker.
2) It makes it so that dawn_use_swiftshader is enabled by default
   when fuzzing, and enabling swiftshader also enables the Vulkan
   backend.

Bug: chromium:1042426
Change-Id: Ic0ae0d59c91476b0079148f33a4b1ebd1cc6743c
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/15462
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
Commit-Queue: Kai Ninomiya <kainino@chromium.org>
---
 scripts/dawn_features.gni                     | 22 ++++++++++---------
 .../DawnWireServerAndVulkanBackendFuzzer.cpp  |  1 +
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/scripts/dawn_features.gni b/scripts/dawn_features.gni
index 2ef8e15190..37a32a05c0 100644
--- a/scripts/dawn_features.gni
+++ b/scripts/dawn_features.gni
@@ -18,6 +18,16 @@ if (build_with_chromium) {
   import("//build/config/sanitizers/sanitizers.gni")
 }
 
+declare_args() {
+  # Enables usage of swiftshader on the Vulkan backend.
+  # Note that this will only work in standalone and in projects that set the
+  # dawn_swiftshader_dir variable in build_overrides/dawn.gni
+  # Because of how the Vulkan loader works, setting this makes Dawn only able
+  # to find the Swiftshader ICD and not the others.
+  # Enabled by default when fuzzing.
+  dawn_use_swiftshader = build_with_chromium && use_fuzzing_engine
+}
+
 declare_args() {
   # Enable Dawn's ASSERTs even in release builds
   dawn_always_assert = false
@@ -42,7 +52,8 @@ declare_args() {
   dawn_enable_opengl = is_linux && !is_chromeos
 
   # Enables the compilation of Dawn's Vulkan backend
-  dawn_enable_vulkan = is_linux || is_win || is_fuchsia || is_android
+  dawn_enable_vulkan =
+      is_linux || is_win || is_fuchsia || is_android || dawn_use_swiftshader
 
   # Enable use of reflection compiler in spirv-cross. This is needed
   # if performing reflection on systems that the platform language
@@ -63,15 +74,6 @@ declare_args() {
 # Put them in two separate declare_args() when setting the value of one
 # argument based on another.
 declare_args() {
-  # Enables usage of swiftshader on the Vulkan backend.
-  # Note that this will only work in standalone and in projects that set the
-  # dawn_swiftshader_dir variable in build_overrides/dawn.gni
-  # Because of how the Vulkan loader works, setting this make Dawn only able
-  # to find the Swiftshader ICD and not the others.
-  # Enabled by default when fuzzing.
-  dawn_use_swiftshader =
-      dawn_enable_vulkan && build_with_chromium && use_fuzzing_engine
-
   # Uses our built version of Vulkan validation layers
   dawn_enable_vulkan_validation_layers =
       dawn_enable_vulkan && ((is_linux && !is_chromeos) || is_win)
diff --git a/src/fuzzers/DawnWireServerAndVulkanBackendFuzzer.cpp b/src/fuzzers/DawnWireServerAndVulkanBackendFuzzer.cpp
index 54fc8cd5f6..b23b132e8c 100644
--- a/src/fuzzers/DawnWireServerAndVulkanBackendFuzzer.cpp
+++ b/src/fuzzers/DawnWireServerAndVulkanBackendFuzzer.cpp
@@ -15,6 +15,7 @@
 #include "DawnWireServerFuzzer.h"
 
 #include "dawn_native/DawnNative.h"
+#include "testing/libfuzzer/libfuzzer_exports.h"
 
 extern "C" int LLVMFuzzerInitialize(int* argc, char*** argv) {
     return DawnWireServerFuzzer::Initialize(argc, argv);