TranslatorESSL.cpp

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Author : Shahbaz Youssefi
Date : 2020-12-24 23:56:39
Hash : 382bf288
Message : Organize AST transforms per backend Most of the AST transforms are written as a workaround to an issue that affects a single backend. This change identifies such transforms and organizes them by backend. They are then only built if the respective backend is. Additionally, about half of the GL transforms are due to mac workarounds, including the large RewriteRowMajorMatrices transform. Mac-specific workarounds are additionally only built on said platform. This change reduces the ANGLE binary size: - 106KB in a Vulkan-only build on Linux - 27KB in a GL-only build on Android (60KB on Linux) Bug: chromium:1084580 Bug: chromium:1161513 Change-Id: I64b334332c0d4f848756c6538af0d8d96864c7e9 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2601346 Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Tim Van Patten <timvp@google.com>

src/compiler/translator/TranslatorESSL.cpp

//
// Copyright 2002 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//

#include "compiler/translator/TranslatorESSL.h"

#include "angle_gl.h"
#include "compiler/translator/BuiltInFunctionEmulatorGLSL.h"
#include "compiler/translator/OutputESSL.h"
#include "compiler/translator/tree_ops/gl/RecordConstantPrecision.h"

namespace sh
{

TranslatorESSL::TranslatorESSL(sh::GLenum type, ShShaderSpec spec)
    : TCompiler(type, spec, SH_ESSL_OUTPUT)
{}

void TranslatorESSL::initBuiltInFunctionEmulator(BuiltInFunctionEmulator *emu,
                                                 ShCompileOptions compileOptions)
{
    if (compileOptions & SH_EMULATE_ATAN2_FLOAT_FUNCTION)
    {
        InitBuiltInAtanFunctionEmulatorForGLSLWorkarounds(emu);
    }
}

bool TranslatorESSL::translate(TIntermBlock *root,
                               ShCompileOptions compileOptions,
                               PerformanceDiagnostics * /*perfDiagnostics*/)
{
    TInfoSinkBase &sink = getInfoSink().obj;

    int shaderVer = getShaderVersion();
    if (shaderVer > 100)
    {
        sink << "#version " << shaderVer << " es\n";
    }

    // Write built-in extension behaviors.
    writeExtensionBehavior(compileOptions);

    // Write pragmas after extensions because some drivers consider pragmas
    // like non-preprocessor tokens.
    writePragma(compileOptions);

    bool precisionEmulation = false;
    if (!emulatePrecisionIfNeeded(root, sink, &precisionEmulation, SH_ESSL_OUTPUT))
        return false;

    if (!RecordConstantPrecision(this, root, &getSymbolTable()))
    {
        return false;
    }

    // Write emulated built-in functions if needed.
    if (!getBuiltInFunctionEmulator().isOutputEmpty())
    {
        sink << "// BEGIN: Generated code for built-in function emulation\n\n";
        if (getShaderType() == GL_FRAGMENT_SHADER)
        {
            sink << "#if defined(GL_FRAGMENT_PRECISION_HIGH)\n"
                 << "#define emu_precision highp\n"
                 << "#else\n"
                 << "#define emu_precision mediump\n"
                 << "#endif\n\n";
        }
        else
        {
            sink << "#define emu_precision highp\n";
        }

        getBuiltInFunctionEmulator().outputEmulatedFunctions(sink);
        sink << "// END: Generated code for built-in function emulation\n\n";
    }

    // Write array bounds clamping emulation if needed.
    getArrayBoundsClamper().OutputClampingFunctionDefinition(sink);

    if (getShaderType() == GL_FRAGMENT_SHADER)
    {
        EmitEarlyFragmentTestsGLSL(*this, sink);
    }

    if (getShaderType() == GL_COMPUTE_SHADER)
    {
        EmitWorkGroupSizeGLSL(*this, sink);
    }

    if (getShaderType() == GL_GEOMETRY_SHADER_EXT)
    {
        WriteGeometryShaderLayoutQualifiers(
            sink, getGeometryShaderInputPrimitiveType(), getGeometryShaderInvocations(),
            getGeometryShaderOutputPrimitiveType(), getGeometryShaderMaxVertices());
    }

    // Write translated shader.
    TOutputESSL outputESSL(sink, getArrayIndexClampingStrategy(), getHashFunction(), getNameMap(),
                           &getSymbolTable(), getShaderType(), shaderVer, precisionEmulation,
                           compileOptions);

    root->traverse(&outputESSL);

    return true;
}

bool TranslatorESSL::shouldFlattenPragmaStdglInvariantAll()
{
    // If following the spec to the letter, we should not flatten this pragma.
    // However, the spec's wording means that the pragma applies only to outputs.
    // This contradicts the spirit of using the pragma,
    // because if the pragma is used in a vertex shader,
    // the only way to be able to link it to a fragment shader
    // is to manually qualify each of fragment shader's inputs as invariant.
    // Which defeats the purpose of this pragma - temporarily make all varyings
    // invariant for debugging.
    // Thus, we should be non-conformant to spec's letter here and flatten.
    return true;
}

void TranslatorESSL::writeExtensionBehavior(ShCompileOptions compileOptions)
{
    TInfoSinkBase &sink                   = getInfoSink().obj;
    const TExtensionBehavior &extBehavior = getExtensionBehavior();
    for (TExtensionBehavior::const_iterator iter = extBehavior.begin(); iter != extBehavior.end();
         ++iter)
    {
        if (iter->second != EBhUndefined)
        {
            const bool isMultiview = (iter->first == TExtension::OVR_multiview) ||
                                     (iter->first == TExtension::OVR_multiview2);
            if (getResources().NV_shader_framebuffer_fetch &&
                iter->first == TExtension::EXT_shader_framebuffer_fetch)
            {
                sink << "#extension GL_NV_shader_framebuffer_fetch : "
                     << GetBehaviorString(iter->second) << "\n";
            }
            else if (getResources().NV_draw_buffers && iter->first == TExtension::EXT_draw_buffers)
            {
                sink << "#extension GL_NV_draw_buffers : " << GetBehaviorString(iter->second)
                     << "\n";
            }
            else if (isMultiview)
            {
                // Only either OVR_multiview OR OVR_multiview2 should be emitted.
                if ((iter->first != TExtension::OVR_multiview) ||
                    !IsExtensionEnabled(extBehavior, TExtension::OVR_multiview2))
                {
                    EmitMultiviewGLSL(*this, compileOptions, iter->first, iter->second, sink);
                }
            }
            else if (iter->first == TExtension::EXT_geometry_shader)
            {
                sink << "#ifdef GL_EXT_geometry_shader\n"
                     << "#extension GL_EXT_geometry_shader : " << GetBehaviorString(iter->second)
                     << "\n"
                     << "#elif defined GL_OES_geometry_shader\n"
                     << "#extension GL_OES_geometry_shader : " << GetBehaviorString(iter->second)
                     << "\n";
                if (iter->second == EBhRequire)
                {
                    sink << "#else\n"
                         << "#error \"No geometry shader extensions available.\" // Only generate "
                            "this if the extension is \"required\"\n";
                }
                sink << "#endif\n";
            }
            else if (iter->first == TExtension::ANGLE_multi_draw)
            {
                // Don't emit anything. This extension is emulated
                ASSERT((compileOptions & SH_EMULATE_GL_DRAW_ID) != 0);
                continue;
            }
            else if (iter->first == TExtension::ANGLE_base_vertex_base_instance)
            {
                // Don't emit anything. This extension is emulated
                ASSERT((compileOptions & SH_EMULATE_GL_BASE_VERTEX_BASE_INSTANCE) != 0);
                continue;
            }
            else if (iter->first == TExtension::WEBGL_video_texture)
            {
                // Don't emit anything. This extension is emulated
                // TODO(crbug.com/776222): support external image.
                continue;
            }
            else
            {
                sink << "#extension " << GetExtensionNameString(iter->first) << " : "
                     << GetBehaviorString(iter->second) << "\n";
            }
        }
    }
}

}  // namespace sh

kc3-lang/angle/src/compiler/translator/TranslatorESSL.cpp

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kc3-lang/angle /src/compiler/translator/TranslatorESSL.cpp