DirectiveHandler.cpp

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Author : Olli Etuaho
Date : 2014-11-06 17:25:48
Hash : 853dc1ab
Message : Add mediump and lowp precision emulation support for GLSL output This implements the rounding as specified in WEBGL_debug_shader_precision extension proposal for desktop GLSL and ESSL output. The bulk of the new functionality is added in the form of a new EmulatePrecision AST traverser, which inserts calls to the rounding routines angle_frm and angle_frl in the appropriate places, and writes the rounding routines themselves to the shader. Compound assignments which are subject to emulation are transformed from "x op= y" to "angle_compound_op_frm(x, y)", a call to a function which does the appropriate rounding and places the result of the operation to x. The angle_ prefixed names should not clash with user-defined names if name hashing is on. If name hashing is not on, the precision emulation can only be used if the angle_ prefix is reserved for use by ANGLE. To support the rounding routines in output, a new operator type is added for internal helper function calls, which are not subject to name hashing. In ESSL output, all variables are forced to highp when precision emulation is on to ensure consistency with how precision emulation performs on desktop. Comprehensive tests for the added code generation are included. BUG=angle:787 Change-Id: I0d0ad9327888f803a32e79b64b08763c654c913b Reviewed-on: https://chromium-review.googlesource.com/229631 Reviewed-by: Jamie Madill <jmadill@chromium.org> Tested-by: Olli Etuaho <oetuaho@nvidia.com>

src/compiler/translator/DirectiveHandler.cpp

//
// Copyright (c) 2012-2013 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/DirectiveHandler.h"

#include <sstream>

#include "compiler/translator/compilerdebug.h"
#include "compiler/translator/Diagnostics.h"

static TBehavior getBehavior(const std::string& str)
{
    const char kRequire[] = "require";
    const char kEnable[] = "enable";
    const char kDisable[] = "disable";
    const char kWarn[] = "warn";

    if (str == kRequire) return EBhRequire;
    else if (str == kEnable) return EBhEnable;
    else if (str == kDisable) return EBhDisable;
    else if (str == kWarn) return EBhWarn;
    return EBhUndefined;
}

TDirectiveHandler::TDirectiveHandler(TExtensionBehavior& extBehavior,
                                     TDiagnostics& diagnostics,
                                     int& shaderVersion,
                                     bool debugShaderPrecisionSupported)
    : mExtensionBehavior(extBehavior),
      mDiagnostics(diagnostics),
      mShaderVersion(shaderVersion),
      mDebugShaderPrecisionSupported(debugShaderPrecisionSupported)
{
}

TDirectiveHandler::~TDirectiveHandler()
{
}

void TDirectiveHandler::handleError(const pp::SourceLocation& loc,
                                    const std::string& msg)
{
    mDiagnostics.writeInfo(pp::Diagnostics::PP_ERROR, loc, msg, "", "");
}

void TDirectiveHandler::handlePragma(const pp::SourceLocation& loc,
                                     const std::string& name,
                                     const std::string& value,
                                     bool stdgl)
{
    if (stdgl)
    {
        const char kInvariant[] = "invariant";
        const char kAll[] = "all";

        if (name == kInvariant && value == kAll)
            mPragma.stdgl.invariantAll = true;
        // The STDGL pragma is used to reserve pragmas for use by future
        // revisions of GLSL.  Do not generate an error on unexpected
        // name and value.
        return;
    }
    else
    {
        const char kOptimize[] = "optimize";
        const char kDebug[] = "debug";
        const char kDebugShaderPrecision[] = "webgl_debug_shader_precision";
        const char kOn[] = "on";
        const char kOff[] = "off";

        bool invalidValue = false;
        if (name == kOptimize)
        {
            if (value == kOn) mPragma.optimize = true;
            else if (value == kOff) mPragma.optimize = false;
            else invalidValue = true;
        }
        else if (name == kDebug)
        {
            if (value == kOn) mPragma.debug = true;
            else if (value == kOff) mPragma.debug = false;
            else invalidValue = true;
        }
        else if (name == kDebugShaderPrecision && mDebugShaderPrecisionSupported)
        {
            if (value == kOn) mPragma.debugShaderPrecision = true;
            else if (value == kOff) mPragma.debugShaderPrecision = false;
            else invalidValue = true;
        }
        else
        {
            mDiagnostics.report(pp::Diagnostics::PP_UNRECOGNIZED_PRAGMA, loc, name);
            return;
        }

        if (invalidValue)
        {
            mDiagnostics.writeInfo(pp::Diagnostics::PP_ERROR, loc,
                                   "invalid pragma value", value,
                                   "'on' or 'off' expected");
        }
    }
}

void TDirectiveHandler::handleExtension(const pp::SourceLocation& loc,
                                        const std::string& name,
                                        const std::string& behavior)
{
    const char kExtAll[] = "all";

    TBehavior behaviorVal = getBehavior(behavior);
    if (behaviorVal == EBhUndefined)
    {
        mDiagnostics.writeInfo(pp::Diagnostics::PP_ERROR, loc,
                               "behavior", name, "invalid");
        return;
    }

    if (name == kExtAll)
    {
        if (behaviorVal == EBhRequire)
        {
            mDiagnostics.writeInfo(pp::Diagnostics::PP_ERROR, loc,
                                   "extension", name,
                                   "cannot have 'require' behavior");
        }
        else if (behaviorVal == EBhEnable)
        {
            mDiagnostics.writeInfo(pp::Diagnostics::PP_ERROR, loc,
                                   "extension", name,
                                   "cannot have 'enable' behavior");
        }
        else
        {
            for (TExtensionBehavior::iterator iter = mExtensionBehavior.begin();
                 iter != mExtensionBehavior.end(); ++iter)
                iter->second = behaviorVal;
        }
        return;
    }

    TExtensionBehavior::iterator iter = mExtensionBehavior.find(name);
    if (iter != mExtensionBehavior.end())
    {
        iter->second = behaviorVal;
        return;
    }

    pp::Diagnostics::Severity severity = pp::Diagnostics::PP_ERROR;
    switch (behaviorVal) {
      case EBhRequire:
        severity = pp::Diagnostics::PP_ERROR;
        break;
      case EBhEnable:
      case EBhWarn:
      case EBhDisable:
        severity = pp::Diagnostics::PP_WARNING;
        break;
      default:
        UNREACHABLE();
        break;
    }
    mDiagnostics.writeInfo(severity, loc,
                           "extension", name, "is not supported");
}

void TDirectiveHandler::handleVersion(const pp::SourceLocation& loc,
                                      int version)
{
    if (version == 100 ||
        version == 300)
    {
        mShaderVersion = version;
    }
    else
    {
        std::stringstream stream;
        stream << version;
        std::string str = stream.str();
        mDiagnostics.writeInfo(pp::Diagnostics::PP_ERROR, loc,
                               "version number", str, "not supported");
    }
}

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

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