src/compiler/ShaderLang.cpp

//
// Copyright (c) 2002-2010 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.
//

//
// Implement the top-level of interface to the compiler,
// as defined in ShaderLang.h
//

#include "GLSLANG/ShaderLang.h"

#include "compiler/Initialize.h"
#include "compiler/InitializeDll.h"
#include "compiler/ParseHelper.h"
#include "compiler/ShHandle.h"
#include "compiler/SymbolTable.h"

static bool InitializeSymbolTable(
        const TBuiltInStrings& builtInStrings,
        EShLanguage language, EShSpec spec, const TBuiltInResource& resources,
        TInfoSink& infoSink, TSymbolTable& symbolTable)
{
    TIntermediate intermediate(infoSink);
    TExtensionBehavior extBehavior;
    TParseContext parseContext(symbolTable, extBehavior, intermediate, language, spec, infoSink);

    GlobalParseContext = &parseContext;

    setInitialState();

    assert(symbolTable.isEmpty());       
    //
    // Parse the built-ins.  This should only happen once per
    // language symbol table.
    //
    // Push the symbol table to give it an initial scope.  This
    // push should not have a corresponding pop, so that built-ins
    // are preserved, and the test for an empty table fails.
    //
    symbolTable.push();
    
    //Initialize the Preprocessor
    if (InitPreprocessor())
    {
        infoSink.info.message(EPrefixInternalError,  "Unable to intialize the Preprocessor");
        return false;
    }

    for (TBuiltInStrings::const_iterator i = builtInStrings.begin(); i != builtInStrings.end(); ++i)
    {
        const char* builtInShaders[1];
        int builtInLengths[1];

        builtInShaders[0] = (*i).c_str();
        builtInLengths[0] = (int) (*i).size();

        if (PaParseStrings(const_cast<char**>(builtInShaders), builtInLengths, 1, parseContext) != 0)
        {
            infoSink.info.message(EPrefixInternalError, "Unable to parse built-ins");
            return false;
        }
    }

    IdentifyBuiltIns(language, spec, resources, symbolTable);

    FinalizePreprocessor();

    return true;
}

static bool GenerateBuiltInSymbolTable(
        EShLanguage language, EShSpec spec, const TBuiltInResource& resources,
        TInfoSink& infoSink, TSymbolTable& symbolTable)
{
    TBuiltIns builtIns;

    builtIns.initialize(language, spec, resources);
    return InitializeSymbolTable(builtIns.getBuiltInStrings(), language, spec, resources, infoSink, symbolTable);
}

static void DefineExtensionMacros(const TExtensionBehavior& extBehavior)
{
    for (TExtensionBehavior::const_iterator iter = extBehavior.begin();
         iter != extBehavior.end(); ++iter) {
        PredefineIntMacro(iter->first.c_str(), 1);
    }
}

//
// This is the platform independent interface between an OGL driver
// and the shading language compiler.
//

//
// Driver must call this first, once, before doing any other
// compiler operations.
//
int ShInitialize()
{
    if (!InitProcess())
        return 0;

    return 1;
}

//
// Cleanup symbol tables
//
int ShFinalize()
{
    if (!DetachProcess())
        return 0;

    return 1;
}

//
// Initialize built-in resources with minimum expected values.
//
void ShInitBuiltInResource(TBuiltInResource* resources)
{
    // Constants.
    resources->MaxVertexAttribs = 8;
    resources->MaxVertexUniformVectors = 128;
    resources->MaxVaryingVectors = 8;
    resources->MaxVertexTextureImageUnits = 0;
    resources->MaxCombinedTextureImageUnits = 8;
    resources->MaxTextureImageUnits = 8;
    resources->MaxFragmentUniformVectors = 16;
    resources->MaxDrawBuffers = 1;

    // Extensions.
    resources->OES_standard_derivatives = 0;
}

//
// Driver calls these to create and destroy compiler objects.
//
ShHandle ShConstructCompiler(EShLanguage language, EShSpec spec, const TBuiltInResource* resources)
{
    if (!InitThread())
        return 0;

    TShHandleBase* base = static_cast<TShHandleBase*>(ConstructCompiler(language, spec));
    TCompiler* compiler = base->getAsCompiler();
    if (compiler == 0)
        return 0;

    // Generate built-in symbol table.
    if (!GenerateBuiltInSymbolTable(language, spec, *resources, compiler->getInfoSink(), compiler->getSymbolTable())) {
        ShDestruct(base);
        return 0;
    }
    InitExtensionBehavior(*resources, compiler->getExtensionBehavior());

    return reinterpret_cast<void*>(base);
}

void ShDestruct(ShHandle handle)
{
    if (handle == 0)
        return;

    TShHandleBase* base = static_cast<TShHandleBase*>(handle);

    if (base->getAsCompiler())
        DeleteCompiler(base->getAsCompiler());
}

//
// Do an actual compile on the given strings.  The result is left 
// in the given compile object.
//
// Return:  The return value of ShCompile is really boolean, indicating
// success or failure.
//
int ShCompile(
    const ShHandle handle,
    const char* const shaderStrings[],
    const int numStrings,
    int compileOptions)
{
    if (!InitThread())
        return 0;

    if (handle == 0)
        return 0;

    TShHandleBase* base = reinterpret_cast<TShHandleBase*>(handle);
    TCompiler* compiler = base->getAsCompiler();
    if (compiler == 0)
        return 0;
    
    GlobalPoolAllocator.push();
    TInfoSink& infoSink = compiler->getInfoSink();
    infoSink.info.erase();
    infoSink.debug.erase();
    infoSink.obj.erase();

    if (numStrings == 0)
        return 1;

    TIntermediate intermediate(infoSink);
    TSymbolTable& symbolTable = compiler->getSymbolTable();
    const TExtensionBehavior& extBehavior = compiler->getExtensionBehavior();

    TParseContext parseContext(symbolTable, extBehavior, intermediate,
        compiler->getLanguage(), compiler->getSpec(), infoSink);
    GlobalParseContext = &parseContext;
 
    setInitialState();

    InitPreprocessor();
    DefineExtensionMacros(extBehavior);
    //
    // Parse the application's shaders.  All the following symbol table
    // work will be throw-away, so push a new allocation scope that can
    // be thrown away, then push a scope for the current shader's globals.
    //
    bool success = true;

    symbolTable.push();
    if (!symbolTable.atGlobalLevel())
        parseContext.infoSink.info.message(EPrefixInternalError, "Wrong symbol table level");

    if (PaParseStrings(const_cast<char**>(shaderStrings), 0, numStrings, parseContext))
        success = false;

    if (success && parseContext.treeRoot) {
        success = intermediate.postProcess(parseContext.treeRoot, parseContext.language);
        if (success) {
            if (compileOptions & EShOptIntermediateTree)
                intermediate.outputTree(parseContext.treeRoot);

            //
            // Call the machine dependent compiler
            //
            if (compileOptions & EShOptObjectCode)
                success = compiler->compile(parseContext.treeRoot);

            // TODO(alokp): Extract attributes and uniforms.
            //if (compileOptions & EShOptAttribsUniforms)
        }
    } else if (!success) {
        parseContext.infoSink.info.prefix(EPrefixError);
        parseContext.infoSink.info << parseContext.numErrors << " compilation errors.  No code generated.\n\n";
        success = false;
        if (compileOptions & EShOptIntermediateTree)
            intermediate.outputTree(parseContext.treeRoot);
    } else if (!parseContext.treeRoot) {
        parseContext.error(1, "Unexpected end of file.", "", "");
        parseContext.infoSink.info << parseContext.numErrors << " compilation errors.  No code generated.\n\n";
        success = false;
    }

    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();

    FinalizePreprocessor();
    //
    // Throw away all the temporary memory used by the compilation process.
    //
    GlobalPoolAllocator.pop();

    return success ? 1 : 0;
}

void ShGetInfo(const ShHandle handle, EShInfo pname, int* params)
{
    if (!handle || !params)
        return;

    TShHandleBase* base = static_cast<TShHandleBase*>(handle);
    TCompiler* compiler = base->getAsCompiler();
    if (!compiler) return;

    switch(pname)
    {
    case SH_INFO_LOG_LENGTH:
        *params = compiler->getInfoSink().info.size() + 1;
        break;
    case SH_OBJECT_CODE_LENGTH:
        *params = compiler->getInfoSink().obj.size() + 1;
        break;
    case SH_ACTIVE_UNIFORMS:
        UNIMPLEMENTED();
        break;
    case SH_ACTIVE_UNIFORM_MAX_LENGTH:
        UNIMPLEMENTED();
        break;
    case SH_ACTIVE_ATTRIBUTES:
        UNIMPLEMENTED();
        break;
    case SH_ACTIVE_ATTRIBUTE_MAX_LENGTH:
        UNIMPLEMENTED();
        break;

    default: UNREACHABLE();
    }
}

//
// Return any compiler log of messages for the application.
//
void ShGetInfoLog(const ShHandle handle, char* infoLog)
{
    if (!handle || !infoLog)
        return;

    TShHandleBase* base = static_cast<TShHandleBase*>(handle);
    TCompiler* compiler = base->getAsCompiler();
    if (!compiler) return;

    TInfoSink& infoSink = compiler->getInfoSink();
    strcpy(infoLog, infoSink.info.c_str());
}

//
// Return any object code.
//
void ShGetObjectCode(const ShHandle handle, char* objCode)
{
    if (!handle || !objCode)
        return;

    TShHandleBase* base = static_cast<TShHandleBase*>(handle);
    TCompiler* compiler = base->getAsCompiler();
    if (!compiler) return;

    TInfoSink& infoSink = compiler->getInfoSink();
    strcpy(objCode, infoSink.obj.c_str());
}

void ShGetActiveAttrib(const ShHandle handle,
                       int index,
                       int* length,
                       int* size,
                       EShDataType* type,
                       char* name)
{
    UNIMPLEMENTED();
}

void ShGetActiveUniform(const ShHandle handle,
                        int index,
                        int* length,
                        int* size,
                        EShDataType* type,
                        char* name)
{
    UNIMPLEMENTED();
}