Generate SkSL golden output files from test inputs during the build.

Golden SkSL outputs are intended to eventually replace the majority of
our unit tests, since they can automatically update themselves when we
change implementation details of the compiler.

If you change the compiler output without updating the Golden files, the
CheckGeneratedFiles housekeeper will be triggered. Set
`skia_compile_processors` or `skia_compile_sksl_tests` to true in your
GN args to regenerate them.

Almost all of the tests from SkSLFPTests.cpp and SkSLGLSLTests.cpp can
be migrated into separate unit-test .fp/.sksl files in a followup CL.

hcm@ has signed off on removing the copyright boilerplate preamble from
our unit test files.

Change-Id: I9e24a944bbac8f8efd62c92481b022a0b1ecdd0b
Bug: skia:10694
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/316336
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>

BUILD.gn

@@ -548,7 +548,8 @@ if (skia_lex) {
   }
 }
 
-if (skia_compile_processors) {
+# `Compile Processors` and `Compile SkSL Tests` both rely on skslc.
+if (skia_compile_processors || skia_compile_sksl_tests) {
   executable("skslc") {
     defines = [ "SKSL_STANDALONE" ]
     sources = [ "src/sksl/SkSLMain.cpp" ]
@@ -561,21 +562,6 @@ if (skia_compile_processors) {
     ]
   }
 
-  skia_gpu_processor_outputs = []
-  foreach(src, skia_gpu_processor_sources) {
-    dir = get_path_info(src, "dir")
-    name = get_path_info(src, "name")
-
-    # GN insists its outputs should go somewhere underneath target_out_dir, so we trick it with a
-    # path that starts with target_out_dir and then uses ".." to back up into the src dir.
-    skia_gpu_processor_outputs += [
-      "$target_out_dir/" +
-          rebase_path("$dir/generated/$name.h", target_out_dir),
-      # the script also modifies the corresponding .cpp file, but if we tell GN that it gets
-      # confused due to the same file being named by two different paths
-    ]
-  }
-
   skslc_path = "$root_out_dir/"
   if (host_toolchain != default_toolchain_name) {
     skslc_path += "$host_toolchain/"
@@ -640,6 +626,26 @@ if (skia_compile_processors) {
     ]
     args += rebase_path(dehydrate_sksl_sources)
   }
+} else {
+  group("dehydrate_sksl") {
+  }
+}
+
+skia_gpu_processor_outputs = []
+if (skia_compile_processors) {
+  foreach(src, skia_gpu_processor_sources) {
+    dir = get_path_info(src, "dir")
+    name = get_path_info(src, "name")
+
+    # GN insists its outputs should go somewhere underneath target_out_dir, so we trick it with a
+    # path that starts with target_out_dir and then uses ".." to back up into the src dir.
+    skia_gpu_processor_outputs += [
+      "$target_out_dir/" +
+          rebase_path("$dir/generated/$name.h", target_out_dir),
+      # the script also modifies the corresponding .cpp file, but if we tell GN that it gets
+      # confused due to the same file being named by two different paths
+    ]
+  }
 
   action("compile_processors") {
     script = "gn/compile_processors.py"
@@ -658,10 +664,46 @@ if (skia_compile_processors) {
     args += rebase_path(skia_gpu_processor_sources)
   }
 } else {
-  skia_gpu_processor_outputs = []
   group("compile_processors") {
   }
-  group("dehydrate_sksl") {
+}
+
+if (skia_compile_sksl_tests) {
+  import("gn/sksl_tests.gni")
+  sksl_fp_tests_outputs = []
+  foreach(src, sksl_fp_tests_sources) {
+    dir = get_path_info(src, "dir")
+    name = get_path_info(src, "name")
+    sksl_fp_tests_outputs += [
+      "$target_out_dir/" + rebase_path("$dir/golden/$name.cpp", target_out_dir),
+      "$target_out_dir/" + rebase_path("$dir/golden/$name.h", target_out_dir),
+    ]
+  }
+
+  sksl_glsl_tests_outputs = []
+  foreach(src, sksl_glsl_tests_sources) {
+    dir = get_path_info(src, "dir")
+    name = get_path_info(src, "name")
+    sksl_glsl_tests_outputs +=
+        [ "$target_out_dir/" +
+          rebase_path("$dir/golden/$name.glsl", target_out_dir) ]
+  }
+
+  action("compile_sksl_tests") {
+    script = "gn/compile_sksl_tests.py"
+    deps = [
+      ":create_sksl_fp",
+      ":sksl_pre_includes",
+      ":skslc(//gn/toolchain:$host_toolchain)",
+    ]
+    sources = sksl_fp_tests_sources + sksl_glsl_tests_sources
+    outputs = sksl_fp_tests_outputs + sksl_glsl_tests_outputs
+    args = [ rebase_path(skslc_path) ]
+    args += rebase_path(sksl_fp_tests_sources)
+    args += rebase_path(sksl_glsl_tests_sources)
+  }
+} else {
+  group("compile_sksl_tests") {
   }
 }
 
@@ -669,6 +711,7 @@ optional("gpu") {
   enabled = skia_enable_gpu
   deps = [
     ":compile_processors",
+    ":compile_sksl_tests",
     ":dehydrate_sksl",
     ":run_sksllex",
   ]

PRESUBMIT.py

@@ -135,7 +135,8 @@ def _CopyrightChecks(input_api, output_api, source_file_filter=None):
       r'Copyright (\([cC]\) )?%s \w+' % years_pattern)
 
   for affected_file in input_api.AffectedSourceFiles(source_file_filter):
-    if 'third_party' in affected_file.LocalPath():
+    if ('third_party/' in affected_file.LocalPath() or
+        'tests/sksl/' in affected_file.LocalPath()):
       continue
     contents = input_api.ReadFile(affected_file, 'rb')
     if not re.search(copyright_pattern, contents):

gn/compile_sksl_tests.py

@@ -0,0 +1,37 @@
+#!/usr/bin/env python
+#
+# Copyright 2020 Google LLC
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import os
+import subprocess
+import sys
+
+skslc = sys.argv[1]
+inputs = sys.argv[2:]
+
+for input in inputs:
+    try:
+        noExt, ext = os.path.splitext(input)
+        head, tail = os.path.split(noExt)
+        targetDir = os.path.join(head, "golden")
+        if not os.path.isdir(targetDir):
+            os.mkdir(targetDir)
+        target = os.path.join(targetDir, tail)
+        if ext == ".fp":
+            subprocess.check_output([skslc, input, target + ".h"],
+                                    stderr=subprocess.STDOUT)
+            subprocess.check_output([skslc, input, target + ".cpp"],
+                                    stderr=subprocess.STDOUT)
+        elif ext == ".sksl":
+            subprocess.check_output([skslc, input, target + ".glsl"],
+                                    stderr=subprocess.STDOUT)
+        else:
+            print("### Unrecognized file type for " + input + ", skipped")
+
+    except subprocess.CalledProcessError as err:
+        print("### Error compiling " + input + ":")
+        print(err.output)
+        exit(1)

gn/skia.gni

@@ -96,6 +96,7 @@ declare_args() {
 }
 
 declare_args() {
+  skia_compile_sksl_tests = skia_compile_processors
   skia_enable_fontmgr_android = skia_use_expat && skia_use_freetype
   skia_enable_fontmgr_custom_directory = skia_use_freetype && !is_fuchsia
   skia_enable_fontmgr_custom_embedded = skia_use_freetype && !is_fuchsia

gn/sksl_tests.gni

@@ -0,0 +1,11 @@
+# Copyright 2020 Google LLC
+#
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# Things are easiest for everyone if these source paths are absolute.
+_tests = get_path_info("../tests", "abspath")
+
+sksl_fp_tests_sources = [ "$_tests/sksl/fp/GrHelloWorld.fp" ]
+
+sksl_glsl_tests_sources = [ "$_tests/sksl/glsl/HelloWorld.sksl" ]

infra/bots/recipe_modules/build/default.py

@@ -134,6 +134,7 @@ def compile_fn(api, checkout_root, out_dir):
   if 'CheckGeneratedFiles' in extra_tokens:
     compiler = 'Clang'
     args['skia_compile_processors'] = 'true'
+    args['skia_compile_sksl_tests'] = 'true'
     args['skia_generate_workarounds'] = 'true'
 
   # ccache + clang-tidy.sh chokes on the argument list.

infra/bots/recipe_modules/build/examples/full.expected/Housekeeper-PerCommit-CheckGeneratedFiles.json

@@ -66,7 +66,7 @@
       "[START_DIR]/cache/work/skia/bin/gn",
       "gen",
       "[START_DIR]/cache/work/skia/out/Housekeeper-PerCommit-CheckGeneratedFiles/Release",
-      "--args=cc=\"[START_DIR]/clang_linux/bin/clang\" cc_wrapper=\"[START_DIR]/ccache_linux/bin/ccache\" cxx=\"[START_DIR]/clang_linux/bin/clang++\" extra_cflags=[\"-B[START_DIR]/clang_linux/bin\", \"-DDUMMY_clang_linux_version=42\"] extra_ldflags=[\"-B[START_DIR]/clang_linux/bin\", \"-fuse-ld=lld\", \"-L[START_DIR]/clang_linux/lib\"] is_debug=false skia_compile_processors=true skia_generate_workarounds=true werror=true"
+      "--args=cc=\"[START_DIR]/clang_linux/bin/clang\" cc_wrapper=\"[START_DIR]/ccache_linux/bin/ccache\" cxx=\"[START_DIR]/clang_linux/bin/clang++\" extra_cflags=[\"-B[START_DIR]/clang_linux/bin\", \"-DDUMMY_clang_linux_version=42\"] extra_ldflags=[\"-B[START_DIR]/clang_linux/bin\", \"-fuse-ld=lld\", \"-L[START_DIR]/clang_linux/lib\"] is_debug=false skia_compile_processors=true skia_compile_sksl_tests=true skia_generate_workarounds=true werror=true"
     ],
     "cwd": "[START_DIR]/cache/work/skia",
     "env": {

infra/bots/recipes/check_generated_files.expected/Housekeeper-PerCommit-CheckGeneratedFiles.json

@@ -262,7 +262,7 @@
       "[START_DIR]/cache/work/skia/bin/gn",
       "gen",
       "[START_DIR]/build/out/Release",
-      "--args=cc=\"[START_DIR]/clang_linux/bin/clang\" cc_wrapper=\"[START_DIR]/ccache_linux/bin/ccache\" cxx=\"[START_DIR]/clang_linux/bin/clang++\" extra_cflags=[\"-B[START_DIR]/clang_linux/bin\", \"-DDUMMY_clang_linux_version=42\"] extra_ldflags=[\"-B[START_DIR]/clang_linux/bin\", \"-fuse-ld=lld\", \"-L[START_DIR]/clang_linux/lib\"] is_debug=false skia_compile_processors=true skia_generate_workarounds=true werror=true"
+      "--args=cc=\"[START_DIR]/clang_linux/bin/clang\" cc_wrapper=\"[START_DIR]/ccache_linux/bin/ccache\" cxx=\"[START_DIR]/clang_linux/bin/clang++\" extra_cflags=[\"-B[START_DIR]/clang_linux/bin\", \"-DDUMMY_clang_linux_version=42\"] extra_ldflags=[\"-B[START_DIR]/clang_linux/bin\", \"-fuse-ld=lld\", \"-L[START_DIR]/clang_linux/lib\"] is_debug=false skia_compile_processors=true skia_compile_sksl_tests=true skia_generate_workarounds=true werror=true"
     ],
     "cwd": "[START_DIR]/cache/work/skia",
     "env": {

tests/sksl/fp/GrHelloWorld.fp

@@ -0,0 +1,5 @@
+/* HELLO WORLD */
+
+void main() {
+    sk_OutColor = half4(1);
+}

tests/sksl/fp/golden/GrHelloWorld.cpp

@@ -0,0 +1,55 @@
+/* HELLO WORLD */
+
+/**************************************************************************************************
+ *** This file was autogenerated from GrHelloWorld.fp; do not modify.
+ **************************************************************************************************/
+#include "GrHelloWorld.h"
+
+#include "src/core/SkUtils.h"
+#include "src/gpu/GrTexture.h"
+#include "src/gpu/glsl/GrGLSLFragmentProcessor.h"
+#include "src/gpu/glsl/GrGLSLFragmentShaderBuilder.h"
+#include "src/gpu/glsl/GrGLSLProgramBuilder.h"
+#include "src/sksl/SkSLCPP.h"
+#include "src/sksl/SkSLUtil.h"
+class GrGLSLHelloWorld : public GrGLSLFragmentProcessor {
+public:
+    GrGLSLHelloWorld() {}
+    void emitCode(EmitArgs& args) override {
+        GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
+        const GrHelloWorld& _outer = args.fFp.cast<GrHelloWorld>();
+        (void) _outer;
+        fragBuilder->codeAppendf(
+R"SkSL(%s = half4(1.0);
+)SkSL"
+, args.fOutputColor);
+    }
+private:
+    void onSetData(const GrGLSLProgramDataManager& pdman, const GrFragmentProcessor& _proc) override {
+    }
+};
+GrGLSLFragmentProcessor* GrHelloWorld::onCreateGLSLInstance() const {
+    return new GrGLSLHelloWorld();
+}
+void GrHelloWorld::onGetGLSLProcessorKey(const GrShaderCaps& caps, GrProcessorKeyBuilder* b) const {
+}
+bool GrHelloWorld::onIsEqual(const GrFragmentProcessor& other) const {
+    const GrHelloWorld& that = other.cast<GrHelloWorld>();
+    (void) that;
+    return true;
+}
+bool GrHelloWorld::usesExplicitReturn() const {
+    return false;
+}
+GrHelloWorld::GrHelloWorld(const GrHelloWorld& src)
+: INHERITED(kGrHelloWorld_ClassID, src.optimizationFlags()) {
+        this->cloneAndRegisterAllChildProcessors(src);
+}
+std::unique_ptr<GrFragmentProcessor> GrHelloWorld::clone() const {
+    return std::make_unique<GrHelloWorld>(*this);
+}
+#if GR_TEST_UTILS
+SkString GrHelloWorld::onDumpInfo() const {
+    return SkString();
+}
+#endif

tests/sksl/fp/golden/GrHelloWorld.h

@@ -0,0 +1,37 @@
+/* HELLO WORLD */
+
+/**************************************************************************************************
+ *** This file was autogenerated from GrHelloWorld.fp; do not modify.
+ **************************************************************************************************/
+#ifndef GrHelloWorld_DEFINED
+#define GrHelloWorld_DEFINED
+
+#include "include/core/SkM44.h"
+#include "include/core/SkTypes.h"
+
+
+#include "src/gpu/GrFragmentProcessor.h"
+
+class GrHelloWorld : public GrFragmentProcessor {
+public:
+    static std::unique_ptr<GrFragmentProcessor> Make() {
+        return std::unique_ptr<GrFragmentProcessor>(new GrHelloWorld());
+    }
+    GrHelloWorld(const GrHelloWorld& src);
+    std::unique_ptr<GrFragmentProcessor> clone() const override;
+    const char* name() const override { return "HelloWorld"; }
+    bool usesExplicitReturn() const override;
+private:
+    GrHelloWorld()
+    : INHERITED(kGrHelloWorld_ClassID, kNone_OptimizationFlags) {
+    }
+    GrGLSLFragmentProcessor* onCreateGLSLInstance() const override;
+    void onGetGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder*) const override;
+    bool onIsEqual(const GrFragmentProcessor&) const override;
+#if GR_TEST_UTILS
+    SkString onDumpInfo() const override;
+#endif
+    GR_DECLARE_FRAGMENT_PROCESSOR_TEST
+    using INHERITED = GrFragmentProcessor;
+};
+#endif

tests/sksl/glsl/HelloWorld.sksl

@@ -0,0 +1 @@
+void main() { sk_FragColor = half4(0.75); }

tests/sksl/glsl/golden/HelloWorld.glsl

@@ -0,0 +1,7 @@
+
+precision mediump float;
+precision mediump sampler2D;
+out mediump vec4 sk_FragColor;
+void main() {
+    sk_FragColor = vec4(0.75);
+}

tools/rewrite_includes.py

@@ -70,7 +70,9 @@ def to_rewrite():
 # Rewrite any #includes relative to Skia's top-level directory.
 need_rewriting = []
 for file_path in to_rewrite():
-  if 'generated' in file_path or 'third_party/skcms' in file_path:
+  if ('/generated/' in file_path or
+      'tests/sksl/' in file_path or
+      'third_party/skcms' in file_path):
     continue
   if (file_path.endswith('.h') or
       file_path.endswith('.c') or