Make dawn_platform a component.

Bug: None
Change-Id: I29c20cd3dac759afee23bdaf5a4391081e29cbaa
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/31900
Commit-Queue: Jiawei Shao <jiawei.shao@intel.com>
Reviewed-by: Austin Eng <enga@chromium.org>
Reviewed-by: Jiawei Shao <jiawei.shao@intel.com>

src/dawn_platform/BUILD.gn

@@ -14,11 +14,16 @@
 
 import("../../scripts/dawn_overrides_with_defaults.gni")
 
-source_set("dawn_platform") {
-  configs += [ "${dawn_root}/src/common:dawn_internal" ]
+import("${dawn_root}/scripts/dawn_component.gni")
+
+dawn_component("dawn_platform") {
+  DEFINE_PREFIX = "DAWN_PLATFORM"
+
+  configs = [ "${dawn_root}/src/common:dawn_internal" ]
 
   sources = [
     "${dawn_root}/src/include/dawn_platform/DawnPlatform.h",
+    "${dawn_root}/src/include/dawn_platform/dawn_platform_export.h",
     "DawnPlatform.cpp",
     "tracing/EventTracer.cpp",
     "tracing/EventTracer.h",

src/dawn_platform/CMakeLists.txt

@@ -12,9 +12,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-add_library(dawn_platform STATIC ${DAWN_DUMMY_FILE})
+add_library(dawn_platform ${DAWN_DUMMY_FILE})
+
+target_compile_definitions(dawn_platform PRIVATE "DAWN_PLATFORM_IMPLEMENTATION")
+if(BUILD_SHARED_LIBS)
+    target_compile_definitions(dawn_platform PRIVATE "DAWN_PLATFORM_SHARED_LIBRARY")
+endif()
+
 target_sources(dawn_platform PRIVATE
     "${DAWN_INCLUDE_DIR}/dawn_platform/DawnPlatform.h"
+    "${DAWN_INCLUDE_DIR}/dawn_platform/dawn_platform_export.h"
     "DawnPlatform.cpp"
     "tracing/EventTracer.cpp"
     "tracing/EventTracer.h"

src/dawn_platform/tracing/EventTracer.h

@@ -15,7 +15,9 @@
 #ifndef DAWNPLATFORM_TRACING_EVENTTRACER_H_
 #define DAWNPLATFORM_TRACING_EVENTTRACER_H_
 
-#include <stdint.h>
+#include "dawn_platform/dawn_platform_export.h"
+
+#include <cstdint>
 
 namespace dawn_platform {
 
@@ -26,20 +28,22 @@ namespace dawn_platform {
 
         using TraceEventHandle = uint64_t;
 
-        const unsigned char* GetTraceCategoryEnabledFlag(Platform* platform,
-                                                         TraceCategory category);
+        DAWN_PLATFORM_EXPORT const unsigned char* GetTraceCategoryEnabledFlag(
+            Platform* platform,
+            TraceCategory category);
 
         // TODO(enga): Simplify this API.
-        TraceEventHandle AddTraceEvent(Platform* platform,
-                                       char phase,
-                                       const unsigned char* categoryGroupEnabled,
-                                       const char* name,
-                                       uint64_t id,
-                                       int numArgs,
-                                       const char** argNames,
-                                       const unsigned char* argTypes,
-                                       const uint64_t* argValues,
-                                       unsigned char flags);
+        DAWN_PLATFORM_EXPORT TraceEventHandle
+        AddTraceEvent(Platform* platform,
+                      char phase,
+                      const unsigned char* categoryGroupEnabled,
+                      const char* name,
+                      uint64_t id,
+                      int numArgs,
+                      const char** argNames,
+                      const unsigned char* argTypes,
+                      const uint64_t* argValues,
+                      unsigned char flags);
 
     }  // namespace tracing
 }  // namespace dawn_platform

src/include/dawn_platform/DawnPlatform.h

@@ -15,9 +15,9 @@
 #ifndef DAWNPLATFORM_DAWNPLATFORM_H_
 #define DAWNPLATFORM_DAWNPLATFORM_H_
 
-#include <dawn_native/dawn_native_export.h>
+#include "dawn_platform/dawn_platform_export.h"
 
-#include <stdint.h>
+#include <cstdint>
 
 namespace dawn_platform {
 
@@ -28,7 +28,7 @@ namespace dawn_platform {
         GPUWork,     // Actual GPU work
     };
 
-    class Platform {
+    class DAWN_PLATFORM_EXPORT Platform {
       public:
         Platform();
         virtual ~Platform();

src/include/dawn_platform/dawn_platform_export.h

@@ -0,0 +1,36 @@
+// Copyright 2020 The Dawn Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef DAWNPLATFORM_EXPORT_H_
+#define DAWNPLATFORM_EXPORT_H_
+
+#if defined(DAWN_PLATFORM_SHARED_LIBRARY)
+#    if defined(_WIN32)
+#        if defined(DAWN_PLATFORM_IMPLEMENTATION)
+#            define DAWN_PLATFORM_EXPORT __declspec(dllexport)
+#        else
+#            define DAWN_PLATFORM_EXPORT __declspec(dllimport)
+#        endif
+#    else  // defined(_WIN32)
+#        if defined(DAWN_PLATFORM_IMPLEMENTATION)
+#            define DAWN_PLATFORM_EXPORT __attribute__((visibility("default")))
+#        else
+#            define DAWN_PLATFORM_EXPORT
+#        endif
+#    endif  // defined(_WIN32)
+#else       // defined(DAWN_PLATFORM_SHARED_LIBRARY)
+#    define DAWN_PLATFORM_EXPORT
+#endif  // defined(DAWN_PLATFORM_SHARED_LIBRARY)
+
+#endif  // DAWNPLATFORM_EXPORT_H_