Compiler.cpp

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Author : Jamie Madill
Date : 2013-07-12 14:51:11
Hash : 1b45214a
Message : Fix the reported shader gl_MaxDrawBuffers to be compliant with the new EXT_draw_buffers spec. From the extension spec: "8) What value should gl_MaxDrawBuffers in the shading language report?" "RESOLVE: It should match MAX_DRAW_BUFFERS_EXT from the API. None of the API or GLSL specifications explicitly state the linkage between API and SL constants, but it seems logical that one would expect them to match, regardless of whether or not an extension directive is used in the shading language." TRAC #23509 Signed-off-by: Shannon Woods Signed-off-by: Nicolas Capens Authored-by: Jamie Madill
src/compiler/Compiler.cpp
//
// Copyright (c) 2002-2013 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/BuiltInFunctionEmulator.h"
#include "compiler/DetectCallDepth.h"
#include "compiler/ForLoopUnroll.h"
#include "compiler/Initialize.h"
#include "compiler/InitializeParseContext.h"
#include "compiler/MapLongVariableNames.h"
#include "compiler/ParseHelper.h"
#include "compiler/RenameFunction.h"
#include "compiler/ShHandle.h"
#include "compiler/ValidateLimitations.h"
#include "compiler/ValidateOutputs.h"
#include "compiler/VariablePacker.h"
#include "compiler/depgraph/DependencyGraph.h"
#include "compiler/depgraph/DependencyGraphOutput.h"
#include "compiler/timing/RestrictFragmentShaderTiming.h"
#include "compiler/timing/RestrictVertexShaderTiming.h"
#include "third_party/compiler/ArrayBoundsClamper.h"

bool isWebGLBasedSpec(ShShaderSpec spec)
{
     return spec == SH_WEBGL_SPEC || spec == SH_CSS_SHADERS_SPEC;
}

namespace {
class TScopedPoolAllocator {
public:
    TScopedPoolAllocator(TPoolAllocator* allocator, bool pushPop)
        : mAllocator(allocator), mPushPopAllocator(pushPop) {
        if (mPushPopAllocator) mAllocator->push();
        SetGlobalPoolAllocator(mAllocator);
    }
    ~TScopedPoolAllocator() {
        SetGlobalPoolAllocator(NULL);
        if (mPushPopAllocator) mAllocator->pop();
    }

private:
    TPoolAllocator* mAllocator;
    bool mPushPopAllocator;
};
}  // namespace

TShHandleBase::TShHandleBase() {
    allocator.push();
    SetGlobalPoolAllocator(&allocator);
}

TShHandleBase::~TShHandleBase() {
    SetGlobalPoolAllocator(NULL);
    allocator.popAll();
}

TCompiler::TCompiler(ShShaderType type, ShShaderSpec spec)
    : shaderType(type),
      shaderSpec(spec),
      maxUniformVectors(0),
      maxExpressionComplexity(0),
      maxCallStackDepth(0),
      fragmentPrecisionHigh(false),
      clampingStrategy(SH_CLAMP_WITH_CLAMP_INTRINSIC),
      builtInFunctionEmulator(type)
{
    longNameMap = LongNameMap::GetInstance();
}

TCompiler::~TCompiler()
{
    ASSERT(longNameMap);
    longNameMap->Release();
}

bool TCompiler::Init(const ShBuiltInResources& resources)
{
    shaderVersion = 100;
    maxUniformVectors = (shaderType == SH_VERTEX_SHADER) ?
        resources.MaxVertexUniformVectors :
        resources.MaxFragmentUniformVectors;
    maxExpressionComplexity = resources.MaxExpressionComplexity;
    maxCallStackDepth = resources.MaxCallStackDepth;
    TScopedPoolAllocator scopedAlloc(&allocator, false);

    // Generate built-in symbol table.
    if (!InitBuiltInSymbolTable(resources))
        return false;
    InitExtensionBehavior(resources, extensionBehavior);
    fragmentPrecisionHigh = resources.FragmentPrecisionHigh == 1;

    arrayBoundsClamper.SetClampingStrategy(resources.ArrayIndexClampingStrategy);
    clampingStrategy = resources.ArrayIndexClampingStrategy;

    hashFunction = resources.HashFunction;

    return true;
}

bool TCompiler::compile(const char* const shaderStrings[],
                        size_t numStrings,
                        int compileOptions)
{
    TScopedPoolAllocator scopedAlloc(&allocator, true);
    clearResults();

    if (numStrings == 0)
        return true;

    // If compiling for WebGL, validate loop and indexing as well.
    if (isWebGLBasedSpec(shaderSpec))
        compileOptions |= SH_VALIDATE_LOOP_INDEXING;

    // First string is path of source file if flag is set. The actual source follows.
    const char* sourcePath = NULL;
    size_t firstSource = 0;
    if (compileOptions & SH_SOURCE_PATH)
    {
        sourcePath = shaderStrings[0];
        ++firstSource;
    }

    TIntermediate intermediate(infoSink);
    TParseContext parseContext(symbolTable, extensionBehavior, intermediate,
                               shaderType, shaderSpec, compileOptions, true,
                               sourcePath, infoSink);
    parseContext.fragmentPrecisionHigh = fragmentPrecisionHigh;
    GlobalParseContext = &parseContext;

    // We preserve symbols at the built-in level from compile-to-compile.
    // Start pushing the user-defined symbols at global level.
    symbolTable.push();
    if (!symbolTable.atGlobalLevel()) {
        infoSink.info.prefix(EPrefixInternalError);
        infoSink.info << "Wrong symbol table level";
    }

    // Parse shader.
    bool success =
        (PaParseStrings(numStrings - firstSource, &shaderStrings[firstSource], NULL, &parseContext) == 0) &&
        (parseContext.treeRoot != NULL);

    shaderVersion = parseContext.getShaderVersion();

    if (success) {
        TIntermNode* root = parseContext.treeRoot;
        success = intermediate.postProcess(root);

        if (success)
            success = detectCallDepth(root, infoSink, (compileOptions & SH_LIMIT_CALL_STACK_DEPTH) != 0);

        if (success && shaderVersion == 300 && shaderType == SH_FRAGMENT_SHADER)
            success = validateOutputs(root);

        if (success && (compileOptions & SH_VALIDATE_LOOP_INDEXING))
            success = validateLimitations(root);

        if (success && (compileOptions & SH_TIMING_RESTRICTIONS))
            success = enforceTimingRestrictions(root, (compileOptions & SH_DEPENDENCY_GRAPH) != 0);

        if (success && shaderSpec == SH_CSS_SHADERS_SPEC)
            rewriteCSSShader(root);

        // Unroll for-loop markup needs to happen after validateLimitations pass.
        if (success && (compileOptions & SH_UNROLL_FOR_LOOP_WITH_INTEGER_INDEX))
            ForLoopUnroll::MarkForLoopsWithIntegerIndicesForUnrolling(root);

        // Built-in function emulation needs to happen after validateLimitations pass.
        if (success && (compileOptions & SH_EMULATE_BUILT_IN_FUNCTIONS))
            builtInFunctionEmulator.MarkBuiltInFunctionsForEmulation(root);

        // Clamping uniform array bounds needs to happen after validateLimitations pass.
        if (success && (compileOptions & SH_CLAMP_INDIRECT_ARRAY_BOUNDS))
            arrayBoundsClamper.MarkIndirectArrayBoundsForClamping(root);

        // Disallow expressions deemed too complex.
        if (success && (compileOptions & SH_LIMIT_EXPRESSION_COMPLEXITY))
            success = limitExpressionComplexity(root);

        // Call mapLongVariableNames() before collectAttribsUniforms() so in
        // collectAttribsUniforms() we already have the mapped symbol names and
        // we could composite mapped and original variable names.
        // Also, if we hash all the names, then no need to do this for long names.
        if (success && (compileOptions & SH_MAP_LONG_VARIABLE_NAMES) && hashFunction == NULL)
            mapLongVariableNames(root);

        if (success && (compileOptions & SH_ATTRIBUTES_UNIFORMS)) {
            collectAttribsUniforms(root);
            if (compileOptions & SH_ENFORCE_PACKING_RESTRICTIONS) {
                success = enforcePackingRestrictions();
                if (!success) {
                    infoSink.info.prefix(EPrefixError);
                    infoSink.info << "too many uniforms";
                }
            }
        }

        if (success && (compileOptions & SH_INTERMEDIATE_TREE))
            intermediate.outputTree(root);

        if (success && (compileOptions & SH_OBJECT_CODE))
            translate(root);
    }

    // Cleanup memory.
    intermediate.remove(parseContext.treeRoot);
    // Ensure symbol table is returned to the built-in level,
    // throwing away all but the built-ins.
    while (!symbolTable.atBuiltInLevel())
        symbolTable.pop();

    return success;
}

bool TCompiler::InitBuiltInSymbolTable(const ShBuiltInResources &resources)
{
    compileResources = resources;

    assert(symbolTable.isEmpty());
    symbolTable.push();   // COMMON_BUILTINS
    symbolTable.push();   // ESSL1_BUILTINS
    symbolTable.push();   // ESSL3_BUILTINS

    TPublicType integer;
    integer.type = EbtInt;
    integer.primarySize = 1;
    integer.secondarySize = 1;
    integer.array = false;

    TPublicType floatingPoint;
    floatingPoint.type = EbtFloat;
    floatingPoint.primarySize = 1;
    floatingPoint.secondarySize = 1;
    floatingPoint.array = false;

    switch(shaderType)
    {
      case SH_FRAGMENT_SHADER:
        symbolTable.setDefaultPrecision(integer, EbpMedium);
        break;
      case SH_VERTEX_SHADER:
        symbolTable.setDefaultPrecision(integer, EbpHigh);
        symbolTable.setDefaultPrecision(floatingPoint, EbpHigh);
        break;
      default: assert(false && "Language not supported");
    }

    InsertBuiltInFunctions(shaderType, shaderSpec, resources, symbolTable);

    IdentifyBuiltIns(shaderType, shaderSpec, resources, symbolTable);

    return true;
}

void TCompiler::clearResults()
{
    arrayBoundsClamper.Cleanup();
    infoSink.info.erase();
    infoSink.obj.erase();
    infoSink.debug.erase();

    attribs.clear();
    uniforms.clear();

    builtInFunctionEmulator.Cleanup();

    nameMap.clear();
}

bool TCompiler::detectCallDepth(TIntermNode* root, TInfoSink& infoSink, bool limitCallStackDepth)
{
    DetectCallDepth detect(infoSink, limitCallStackDepth, maxCallStackDepth);
    root->traverse(&detect);
    switch (detect.detectCallDepth()) {
        case DetectCallDepth::kErrorNone:
            return true;
        case DetectCallDepth::kErrorMissingMain:
            infoSink.info.prefix(EPrefixError);
            infoSink.info << "Missing main()";
            return false;
        case DetectCallDepth::kErrorRecursion:
            infoSink.info.prefix(EPrefixError);
            infoSink.info << "Function recursion detected";
            return false;
        case DetectCallDepth::kErrorMaxDepthExceeded:
            infoSink.info.prefix(EPrefixError);
            infoSink.info << "Function call stack too deep";
            return false;
        default:
            UNREACHABLE();
            return false;
    }
}

bool TCompiler::validateOutputs(TIntermNode* root)
{
    ValidateOutputs validateOutputs(infoSink.info, compileResources.MaxDrawBuffers);
    root->traverse(&validateOutputs);
    return (validateOutputs.numErrors() == 0);
}

void TCompiler::rewriteCSSShader(TIntermNode* root)
{
    RenameFunction renamer("main(", "css_main(");
    root->traverse(&renamer);
}

bool TCompiler::validateLimitations(TIntermNode* root) {
    ValidateLimitations validate(shaderType, infoSink.info);
    root->traverse(&validate);
    return validate.numErrors() == 0;
}

bool TCompiler::enforceTimingRestrictions(TIntermNode* root, bool outputGraph)
{
    if (shaderSpec != SH_WEBGL_SPEC) {
        infoSink.info << "Timing restrictions must be enforced under the WebGL spec.";
        return false;
    }

    if (shaderType == SH_FRAGMENT_SHADER) {
        TDependencyGraph graph(root);

        // Output any errors first.
        bool success = enforceFragmentShaderTimingRestrictions(graph);
        
        // Then, output the dependency graph.
        if (outputGraph) {
            TDependencyGraphOutput output(infoSink.info);
            output.outputAllSpanningTrees(graph);
        }
        
        return success;
    }
    else {
        return enforceVertexShaderTimingRestrictions(root);
    }
}

bool TCompiler::limitExpressionComplexity(TIntermNode* root)
{
    TIntermTraverser traverser;
    root->traverse(&traverser);
    TDependencyGraph graph(root);

    for (TFunctionCallVector::const_iterator iter = graph.beginUserDefinedFunctionCalls();
         iter != graph.endUserDefinedFunctionCalls();
         ++iter)
    {
        TGraphFunctionCall* samplerSymbol = *iter;
        TDependencyGraphTraverser graphTraverser;
        samplerSymbol->traverse(&graphTraverser);
    }

    if (traverser.getMaxDepth() > maxExpressionComplexity) {
        infoSink.info << "Expression too complex.";
        return false;
    }
    return true;
}

bool TCompiler::enforceFragmentShaderTimingRestrictions(const TDependencyGraph& graph)
{
    RestrictFragmentShaderTiming restrictor(infoSink.info);
    restrictor.enforceRestrictions(graph);
    return restrictor.numErrors() == 0;
}

bool TCompiler::enforceVertexShaderTimingRestrictions(TIntermNode* root)
{
    RestrictVertexShaderTiming restrictor(infoSink.info);
    restrictor.enforceRestrictions(root);
    return restrictor.numErrors() == 0;
}

void TCompiler::collectAttribsUniforms(TIntermNode* root)
{
    CollectAttribsUniforms collect(attribs, uniforms, hashFunction);
    root->traverse(&collect);
}

bool TCompiler::enforcePackingRestrictions()
{
    VariablePacker packer;
    return packer.CheckVariablesWithinPackingLimits(maxUniformVectors, uniforms);
}

void TCompiler::mapLongVariableNames(TIntermNode* root)
{
    ASSERT(longNameMap);
    MapLongVariableNames map(longNameMap);
    root->traverse(&map);
}

int TCompiler::getMappedNameMaxLength() const
{
    return MAX_SHORTENED_IDENTIFIER_SIZE + 1;
}

const TExtensionBehavior& TCompiler::getExtensionBehavior() const
{
    return extensionBehavior;
}

const ShBuiltInResources& TCompiler::getResources() const
{
    return compileResources;
}

const ArrayBoundsClamper& TCompiler::getArrayBoundsClamper() const
{
    return arrayBoundsClamper;
}

ShArrayIndexClampingStrategy TCompiler::getArrayIndexClampingStrategy() const
{
    return clampingStrategy;
}

const BuiltInFunctionEmulator& TCompiler::getBuiltInFunctionEmulator() const
{
    return builtInFunctionEmulator;
}
kc3-lang/angle/src/compiler/Compiler.cpp

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kc3-lang/angle /src/compiler/Compiler.cpp
