DirectXShaderCompiler/tools/clang/lib/Parse/HLSLRootSignature.cpp

//===--- HLSLRootSignature.cpp -- HLSL root signature parsing -------------===//
///////////////////////////////////////////////////////////////////////////////
//                                                                           //
// HLSLRootSignature.cpp                                                     //
// Copyright (C) Microsoft Corporation. All rights reserved.                 //
// This file is distributed under the University of Illinois Open Source     //
// License. See LICENSE.TXT for details.                                     //
//                                                                           //
//  This file implements the parser for the root signature mini-language.    //
//                                                                           //
///////////////////////////////////////////////////////////////////////////////

#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/raw_ostream.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Parse/ParseHLSL.h"
#include "clang/Parse/ParseDiagnostic.h"
#include "dxc/Support/Global.h"
#include "dxc/Support/WinIncludes.h"
#include "dxc/Support/WinFunctions.h"
#include "HLSLRootSignature.h"

#include <float.h>

using namespace llvm;
using namespace hlsl;

// Error codes. These could be useful for localization at some point.
#define ERR_RS_UNEXPECTED_TOKEN             4612  
#define ERR_RS_ROOTFLAGS_MORE_THAN_ONCE     4613  
#define ERR_RS_CREATION_FAILED              4614  
#define ERR_RS_BAD_SM                       4615  
#define ERR_RS_UNDEFINED_REGISTER           4616  
#define ERR_RS_INCORRECT_REGISTER_TYPE      4617  
#define ERR_RS_NOT_ALLOWED_FOR_HS_PATCH_CONST 4618  
#define ERR_RS_WRONG_ROOT_DESC_FLAG         4619  
#define ERR_RS_WRONG_DESC_RANGE_FLAG        4620
#define ERR_RS_LOCAL_FLAG_ON_GLOBAL         4621
#define ERR_RS_BAD_FLOAT                    5000

// Non-throwing new
#define NEW new (std::nothrow)

DEFINE_ENUM_FLAG_OPERATORS(DxilRootSignatureFlags)
DEFINE_ENUM_FLAG_OPERATORS(DxilRootDescriptorFlags)
DEFINE_ENUM_FLAG_OPERATORS(DxilDescriptorRangeFlags)
DEFINE_ENUM_FLAG_OPERATORS(DxilRootSignatureCompilationFlags)

RootSignatureTokenizer::RootSignatureTokenizer(const char *pStr, size_t len)
  : m_pStrPos(pStr)
  , m_pEndPos(pStr + len)
{
    m_TokenBufferIdx = 0;
    ReadNextToken(m_TokenBufferIdx);
}

RootSignatureTokenizer::RootSignatureTokenizer(const char *pStr)
  : m_pStrPos(pStr)
  , m_pEndPos(pStr + strlen(pStr))
{
  m_TokenBufferIdx = 0;
  ReadNextToken(m_TokenBufferIdx);
}

RootSignatureTokenizer::Token
RootSignatureTokenizer::GetToken()
{
    uint32_t CurBufferIdx = m_TokenBufferIdx;
    m_TokenBufferIdx = (m_TokenBufferIdx + 1) % kNumBuffers;
    ReadNextToken(m_TokenBufferIdx);
    return m_Tokens[CurBufferIdx];
}

RootSignatureTokenizer::Token
RootSignatureTokenizer::PeekToken()
{
    return m_Tokens[m_TokenBufferIdx];
}

bool RootSignatureTokenizer::IsDone() const
{
    return m_pStrPos == m_pEndPos;
}

void RootSignatureTokenizer::ReadNextToken(uint32_t BufferIdx)
{
    char *pBuffer = m_TokenStrings[BufferIdx];
    Token &T = m_Tokens[BufferIdx];
    bool bFloat = false;
    bool bKW = false;
    char c = 0;

    EatSpace();

    // Identify token
    uint32_t TokLen = 0;
    char ch;
    // Any time m_pStrPos moves, update ch; no null termination assumptions made.
    // Test ch, not m_StrPos[0], which may be at end.
#define STRPOS_MOVED() ch = m_pStrPos == m_pEndPos ? '\0' : m_pStrPos[0];
    STRPOS_MOVED();
    if(IsSeparator(ch))
    {
        pBuffer[TokLen++] = *m_pStrPos++;
    }
    else if(IsDigit(ch) || ch == '+' || ch == '-' || ch == '.')
    {
        if(ch == '+' || ch == '-')
        {
            pBuffer[TokLen++] = *m_pStrPos++;
            STRPOS_MOVED();
        }

        bool bSeenDigit = false;
        while(IsDigit(ch) && TokLen < kMaxTokenLength)
        {
            pBuffer[TokLen++] = *m_pStrPos++;
            STRPOS_MOVED();
            bSeenDigit = true;
        }
            
        if(ch == '.')
        {
            bFloat = true;
            pBuffer[TokLen++] = *m_pStrPos++;
            STRPOS_MOVED();
            if(!bSeenDigit && !IsDigit(ch))
            {
                goto lUnknownToken;
            }
            while(IsDigit(ch) && TokLen < kMaxTokenLength)
            {
                pBuffer[TokLen++] = *m_pStrPos++;
                STRPOS_MOVED();
                bSeenDigit = true;
            }
        }

        if(!bSeenDigit)
        {
            goto lUnknownToken;
        }

        if(ch == 'e' || ch == 'E')
        {
            bFloat = true;
            pBuffer[TokLen++] = *m_pStrPos++;
            STRPOS_MOVED()
            if(ch == '+' || ch == '-')
            {
                pBuffer[TokLen++] = *m_pStrPos++;
                STRPOS_MOVED();
            }
            if(!IsDigit(ch))
            {
                goto lUnknownToken;
            }
            while(IsDigit(ch) && TokLen < kMaxTokenLength)
            {
                pBuffer[TokLen++] = *m_pStrPos++;
                STRPOS_MOVED();
            }
        }

        if(ch == 'f' || ch == 'F')
        {
            bFloat = true;
            pBuffer[TokLen++] = *m_pStrPos++;
            STRPOS_MOVED();
        }
    }
    else if(IsAlpha(ch) || ch == '_')
    {
        while((IsAlpha(ch) || ch == '_' || IsDigit(ch)) && TokLen < kMaxTokenLength)
        {
            pBuffer[TokLen++] = *m_pStrPos++;
            STRPOS_MOVED();
        }
    }
    else
    {
        while(m_pStrPos < m_pEndPos && TokLen < kMaxTokenLength)
        {
            pBuffer[TokLen++] = *m_pStrPos++;
            STRPOS_MOVED(); // not really needed, but good for consistency
        }
    }
    pBuffer[TokLen] = '\0';
#undef STRPOS_MOVED

    //
    // Classify token
    //
    c = pBuffer[0];

    // Delimiters
    switch(c)
    {
    case '\0':  T = Token(Token::Type::EOL,    pBuffer);    return;
    case ',':   T = Token(Token::Type::Comma,  pBuffer);    return;
    case '(':   T = Token(Token::Type::LParen, pBuffer);    return;
    case ')':   T = Token(Token::Type::RParen, pBuffer);    return;
    case '=':   T = Token(Token::Type::EQ,     pBuffer);    return;
    case '|':   T = Token(Token::Type::OR,     pBuffer);    return;
    }

    // Number
    if(IsDigit(c) || c == '+' || c == '-' || c == '.')
    {
        if(bFloat)
        {
            float v = 0.f;
            if(ToFloat(pBuffer, v))
            {
                T = Token(Token::Type::NumberFloat, pBuffer, v);
                return;
            }
        }
        else
        {
            if(c == '-')
            {
                int n = 0;
                if(ToI32(pBuffer, n))
                {
                    T = Token(Token::Type::NumberI32, pBuffer, (uint32_t)n);
                    return;
                }
            }
            else
            {
                uint32_t n = 0;
                if(ToU32(pBuffer, n))
                {
                    T = Token(Token::Type::NumberU32, pBuffer, n);
                    return;
                }
            }
        }
        
        goto lUnknownToken;
    }

    // Register
    if(IsDigit(pBuffer[1])  &&  (c == 't' || c == 's' || c == 'u' || c == 'b'))
    {
        if(ToRegister(pBuffer, T))
            return;
    }

    // Keyword
#define KW(__name)  ToKeyword(pBuffer, T, #__name, Token::Type::__name)

    // Case-incensitive
    switch(toupper(c))
    {
    case 'A':
        bKW = KW(ALLOW_INPUT_ASSEMBLER_INPUT_LAYOUT) ||
              KW(ALLOW_STREAM_OUTPUT) ||
              KW(addressU) || 
              KW(addressV) || 
              KW(addressW);
        break;

    case 'B':
        bKW = KW(borderColor);
        break;

    case 'C':
        bKW = KW(CBV) ||
              KW(comparisonFunc) ||
              KW(COMPARISON_NEVER) ||
              KW(COMPARISON_LESS) ||
              KW(COMPARISON_EQUAL) ||
              KW(COMPARISON_LESS_EQUAL) ||
              KW(COMPARISON_GREATER) ||
              KW(COMPARISON_NOT_EQUAL) ||
              KW(COMPARISON_GREATER_EQUAL) ||
              KW(COMPARISON_ALWAYS);
        break;

    case 'D':
        bKW = KW(DescriptorTable) || 
              KW(DESCRIPTOR_RANGE_OFFSET_APPEND) ||
              KW(DENY_VERTEX_SHADER_ROOT_ACCESS) || 
              KW(DENY_HULL_SHADER_ROOT_ACCESS) || 
              KW(DENY_DOMAIN_SHADER_ROOT_ACCESS) || 
              KW(DENY_GEOMETRY_SHADER_ROOT_ACCESS) || 
              KW(DENY_PIXEL_SHADER_ROOT_ACCESS) ||
              KW(DESCRIPTORS_VOLATILE) ||
              KW(DATA_VOLATILE) ||
              KW(DATA_STATIC) ||
              KW(DATA_STATIC_WHILE_SET_AT_EXECUTE) ||
              KW(DESCRIPTORS_STATIC_KEEPING_BUFFER_BOUNDS_CHECKS);
          break;

    case 'F':
        bKW = KW(flags) ||
              KW(filter) || 
              KW(FILTER_MIN_MAG_MIP_POINT) || 
              KW(FILTER_MIN_MAG_POINT_MIP_LINEAR) || 
              KW(FILTER_MIN_POINT_MAG_LINEAR_MIP_POINT) || 
              KW(FILTER_MIN_POINT_MAG_MIP_LINEAR) || 
              KW(FILTER_MIN_LINEAR_MAG_MIP_POINT) || 
              KW(FILTER_MIN_LINEAR_MAG_POINT_MIP_LINEAR) || 
              KW(FILTER_MIN_MAG_LINEAR_MIP_POINT) || 
              KW(FILTER_MIN_MAG_MIP_LINEAR) || 
              KW(FILTER_ANISOTROPIC) || 
              KW(FILTER_COMPARISON_MIN_MAG_MIP_POINT) || 
              KW(FILTER_COMPARISON_MIN_MAG_POINT_MIP_LINEAR) || 
              KW(FILTER_COMPARISON_MIN_POINT_MAG_LINEAR_MIP_POINT) || 
              KW(FILTER_COMPARISON_MIN_POINT_MAG_MIP_LINEAR) || 
              KW(FILTER_COMPARISON_MIN_LINEAR_MAG_MIP_POINT) || 
              KW(FILTER_COMPARISON_MIN_LINEAR_MAG_POINT_MIP_LINEAR) || 
              KW(FILTER_COMPARISON_MIN_MAG_LINEAR_MIP_POINT) || 
              KW(FILTER_COMPARISON_MIN_MAG_MIP_LINEAR) || 
              KW(FILTER_COMPARISON_ANISOTROPIC) || 
              KW(FILTER_MINIMUM_MIN_MAG_MIP_POINT) || 
              KW(FILTER_MINIMUM_MIN_MAG_POINT_MIP_LINEAR) || 
              KW(FILTER_MINIMUM_MIN_POINT_MAG_LINEAR_MIP_POINT) || 
              KW(FILTER_MINIMUM_MIN_POINT_MAG_MIP_LINEAR) || 
              KW(FILTER_MINIMUM_MIN_LINEAR_MAG_MIP_POINT) || 
              KW(FILTER_MINIMUM_MIN_LINEAR_MAG_POINT_MIP_LINEAR) || 
              KW(FILTER_MINIMUM_MIN_MAG_LINEAR_MIP_POINT) || 
              KW(FILTER_MINIMUM_MIN_MAG_MIP_LINEAR) || 
              KW(FILTER_MINIMUM_ANISOTROPIC) || 
              KW(FILTER_MAXIMUM_MIN_MAG_MIP_POINT) || 
              KW(FILTER_MAXIMUM_MIN_MAG_POINT_MIP_LINEAR) || 
              KW(FILTER_MAXIMUM_MIN_POINT_MAG_LINEAR_MIP_POINT) || 
              KW(FILTER_MAXIMUM_MIN_POINT_MAG_MIP_LINEAR) || 
              KW(FILTER_MAXIMUM_MIN_LINEAR_MAG_MIP_POINT) || 
              KW(FILTER_MAXIMUM_MIN_LINEAR_MAG_POINT_MIP_LINEAR) || 
              KW(FILTER_MAXIMUM_MIN_MAG_LINEAR_MIP_POINT) || 
              KW(FILTER_MAXIMUM_MIN_MAG_MIP_LINEAR) || 
              KW(FILTER_MAXIMUM_ANISOTROPIC);
        break;

    case 'L':
        bKW = KW(LOCAL_ROOT_SIGNATURE);
        break;

    case 'M':
        bKW = KW(maxAnisotropy) || KW(mipLODBias) || KW(minLOD) || KW(maxLOD);
        break;

    case 'N':
        bKW = KW(numDescriptors) || KW(num32BitConstants);
        break;

    case 'O':
        bKW = KW(offset);
        break;

    case 'R':
        bKW = KW(RootFlags) || KW(RootConstants);
        break;

    case 'S':
        bKW = KW(space) || KW(Sampler) || KW(StaticSampler) || KW(SRV) ||
              KW(SHADER_VISIBILITY_ALL)      ||  KW(SHADER_VISIBILITY_VERTEX) || 
              KW(SHADER_VISIBILITY_HULL)     || KW(SHADER_VISIBILITY_DOMAIN)  ||
              KW(SHADER_VISIBILITY_GEOMETRY) || KW(SHADER_VISIBILITY_PIXEL) ||
              KW(STATIC_BORDER_COLOR_TRANSPARENT_BLACK) ||
              KW(STATIC_BORDER_COLOR_OPAQUE_BLACK) ||
              KW(STATIC_BORDER_COLOR_OPAQUE_WHITE);
        break;

    case 'T':
        bKW = KW(TEXTURE_ADDRESS_WRAP) || 
              KW(TEXTURE_ADDRESS_MIRROR) ||
              KW(TEXTURE_ADDRESS_CLAMP) ||
              KW(TEXTURE_ADDRESS_BORDER) ||
              KW(TEXTURE_ADDRESS_MIRROR_ONCE);
        break;

    case 'U':
        bKW = KW(unbounded) || KW(UAV);
        break;

    case 'V':
        bKW = KW(visibility);
        break;
    }
#undef KW

    if(!bKW) goto lUnknownToken;

    return;

lUnknownToken:
    T = Token(Token::Type::Unknown, pBuffer);
}

void RootSignatureTokenizer::EatSpace()
{
    while(m_pStrPos < m_pEndPos && *m_pStrPos == ' ')
        m_pStrPos++;
}

bool RootSignatureTokenizer::ToI32(LPCSTR pBuf, int & n)
{
    if(pBuf[0] == '\0') return false;

    long long N = _atoi64(pBuf);
    if(N > INT_MAX || N < INT_MIN) return false;

    n = static_cast<int>(N);
    return true;
}

bool RootSignatureTokenizer::ToU32(LPCSTR pBuf, uint32_t & n)
{
    if(pBuf[0] == '\0') return false;

    long long N = _atoi64(pBuf);
    if(N > UINT32_MAX || N < 0) return false;

    n = static_cast<uint32_t>(N);
    return true;
}

bool RootSignatureTokenizer::ToFloat(LPCSTR pBuf, float & n)
{
    if(pBuf[0] == '\0') return false;

    errno = 0;
    double N = strtod(pBuf, NULL);
    if (errno == ERANGE || (N > FLT_MAX || N < -FLT_MAX)) {
      return false;
    }

    n = static_cast<float>(N);
    return true;
}


bool RootSignatureTokenizer::ToRegister(LPCSTR pBuf, Token & T)
{
    uint32_t n;
    if(ToU32(&pBuf[1], n))
    {
        switch(pBuf[0])
        {
        case 't':   T = Token(Token::Type::TReg, pBuf, n);  return true;
        case 's':   T = Token(Token::Type::SReg, pBuf, n);  return true;
        case 'u':   T = Token(Token::Type::UReg, pBuf, n);  return true;
        case 'b':   T = Token(Token::Type::BReg, pBuf, n);  return true;
        }
    }

    return false;
}

bool RootSignatureTokenizer::ToKeyword(LPCSTR pBuf, Token & T, const char *pKeyword, Token::Type Type)
{
    // Tokens are case-insencitive to allow more flexibility for programmers
    if(_stricmp(pBuf, pKeyword) == 0)
    {
        T = Token(Type, pBuf);
        return true;
    }
    else
    {
        T = Token(Token::Type::Unknown, pBuf);
        return false;
    }
}

bool RootSignatureTokenizer::IsSeparator(char c) const
{
    return (c == ',' || c == '=' || c == '|' || c == '('  || c == ')' || c == ' ' || c == '\t' || c == '\n');
}

bool RootSignatureTokenizer::IsDigit(char c) const
{
    return isdigit(c) > 0;
}

bool RootSignatureTokenizer::IsAlpha(char c) const
{
    return isalpha(c) > 0;
}

RootSignatureParser::RootSignatureParser(
    RootSignatureTokenizer *pTokenizer, DxilRootSignatureVersion DefaultVersion,
    DxilRootSignatureCompilationFlags CompilationFlags, llvm::raw_ostream &OS)
    : m_pTokenizer(pTokenizer), m_Version(DefaultVersion), m_CompilationFlags(CompilationFlags), m_OS(OS) {}

HRESULT RootSignatureParser::Parse(DxilVersionedRootSignatureDesc **ppRootSignature)
{
    HRESULT hr = S_OK;
    DxilVersionedRootSignatureDesc *pRS = NULL;

    DXASSERT(!((bool)(m_CompilationFlags & DxilRootSignatureCompilationFlags::GlobalRootSignature) && 
               (bool)(m_CompilationFlags & DxilRootSignatureCompilationFlags::LocalRootSignature)),
             "global and local cannot be both set");

    if(ppRootSignature != NULL)
    {
        IFC(ParseRootSignature(&pRS));
        *ppRootSignature = pRS;
    }

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::GetAndMatchToken(TokenType & Token, TokenType::Type Type)
{
    HRESULT hr = S_OK;
    Token = m_pTokenizer->GetToken();
    if(Token.GetType() != Type)
        IFC(Error(ERR_RS_UNEXPECTED_TOKEN, "Unexpected token '%s'", Token.GetStr()));

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::Error(uint32_t uErrorNum, LPCSTR pError, ...)
{
    va_list Args;
    char msg[512];
    va_start(Args, pError);
    vsprintf_s(msg, pError, Args);
    va_end(Args);
    try {
      m_OS << msg;
    }
    CATCH_CPP_RETURN_HRESULT();
    return E_FAIL;
}

HRESULT RootSignatureParser::ParseRootSignature(DxilVersionedRootSignatureDesc **ppRootSignature)
{
    HRESULT hr = S_OK;
    TokenType Token;
    bool bSeenFlags = false;
    SmallVector<DxilRootParameter1, 8> RSParameters;
    DxilRootParameter1 *pRSParams = NULL;
    SmallVector<DxilStaticSamplerDesc, 8> StaticSamplers;
    DxilStaticSamplerDesc *pStaticSamplers = NULL;
    DxilVersionedRootSignatureDesc *pRS = NULL;

    *ppRootSignature = NULL;
    IFCOOM(pRS = NEW DxilVersionedRootSignatureDesc);
    // Always parse root signature string to the latest version.
    pRS->Version = DxilRootSignatureVersion::Version_1_1;
    memset(&pRS->Desc_1_1, 0, sizeof(pRS->Desc_1_1));

    Token = m_pTokenizer->PeekToken();
    while(Token.GetType() != TokenType::EOL)
    {
        switch(Token.GetType())
        {
        case TokenType::RootFlags:
            if(!bSeenFlags)
            {
                IFC(ParseRootSignatureFlags(pRS->Desc_1_1.Flags));
                bSeenFlags = true;
            }
            else
            {
                IFC(Error(ERR_RS_ROOTFLAGS_MORE_THAN_ONCE, "RootFlags cannot be specified more than once"));
            }
            break;

        case TokenType::RootConstants:
        {
            DxilRootParameter1 P;
            IFC(ParseRootConstants(P));
            RSParameters.push_back(P);
            break;
        }

        case TokenType::CBV:
        {
            DxilRootParameter1 P;
            IFC(ParseRootShaderResource(Token.GetType(), TokenType::BReg, DxilRootParameterType::CBV, P));
            RSParameters.push_back(P);
            break;
        }

        case TokenType::SRV:
        {
            DxilRootParameter1 P;
            IFC(ParseRootShaderResource(Token.GetType(), TokenType::TReg, DxilRootParameterType::SRV, P));
            RSParameters.push_back(P);
            break;
        }

        case TokenType::UAV:
        {
            DxilRootParameter1 P;
            IFC(ParseRootShaderResource(Token.GetType(), TokenType::UReg, DxilRootParameterType::UAV, P));
            RSParameters.push_back(P);
            break;
        }

        case TokenType::DescriptorTable:
        {
            DxilRootParameter1 P;
            IFC(ParseRootDescriptorTable(P));
            RSParameters.push_back(P);
            break;
        }

        case TokenType::StaticSampler:
        {
            DxilStaticSamplerDesc P;
            IFC(ParseStaticSampler(P));
            StaticSamplers.push_back(P);
            break;
        }

        default:
            IFC(Error(ERR_RS_UNEXPECTED_TOKEN, "Unexpected token '%s' when parsing root signature", Token.GetStr()));
        }

        Token = m_pTokenizer->GetToken();
        if(Token.GetType() == TokenType::EOL)
            break;

        // Consume ','
        if(Token.GetType() != TokenType::Comma)
            IFC(Error(ERR_RS_UNEXPECTED_TOKEN, "Expected ',', found: '%s'", Token.GetStr()));

        Token = m_pTokenizer->PeekToken();
    }
    
    if(RSParameters.size() > 0)
    {
        IFCOOM(pRSParams = NEW DxilRootParameter1[RSParameters.size()]);
        pRS->Desc_1_1.NumParameters = RSParameters.size();
        memcpy(pRSParams, RSParameters.data(), pRS->Desc_1_1.NumParameters*sizeof(DxilRootParameter1));
        pRS->Desc_1_1.pParameters = pRSParams;
    }
    if(StaticSamplers.size() > 0)
    {
        IFCOOM(pStaticSamplers = NEW DxilStaticSamplerDesc[StaticSamplers.size()]);
        pRS->Desc_1_1.NumStaticSamplers = StaticSamplers.size();
        memcpy(pStaticSamplers, StaticSamplers.data(), pRS->Desc_1_1.NumStaticSamplers*sizeof(DxilStaticSamplerDesc));
        pRS->Desc_1_1.pStaticSamplers = pStaticSamplers;
    }

    // Set local signature flag if not already on
    if ((bool)(m_CompilationFlags & DxilRootSignatureCompilationFlags::LocalRootSignature))
      pRS->Desc_1_1.Flags |= DxilRootSignatureFlags::LocalRootSignature;

    // Down-convert root signature to the right version, if needed.
    if(pRS->Version != m_Version)
    {
        DxilVersionedRootSignatureDesc *pRS1 = NULL;
        try {
          hlsl::ConvertRootSignature(pRS, m_Version, (const DxilVersionedRootSignatureDesc **)&pRS1);
        }
        CATCH_CPP_ASSIGN_HRESULT();
        IFC(hr);
        hlsl::DeleteRootSignature(pRS);
        pRS = pRS1;
    }

    *ppRootSignature = pRS;

Cleanup:
    if(FAILED(hr))
    {
        hlsl::DeleteRootSignature(pRS);
    }
    return hr;
}

HRESULT RootSignatureParser::ParseRootSignatureFlags(DxilRootSignatureFlags & Flags)
{
    //RootFlags(ALLOW_INPUT_ASSEMBLER_INPUT_LAYOUT | DENY_VERTEX_SHADER_ROOT_ACCESS)
    //  ALLOW_INPUT_ASSEMBLER_INPUT_LAYOUT
    //  DENY_VERTEX_SHADER_ROOT_ACCESS
    //  DENY_HULL_SHADER_ROOT_ACCESS
    //  DENY_DOMAIN_SHADER_ROOT_ACCESS
    //  DENY_GEOMETRY_SHADER_ROOT_ACCESS
    //  DENY_PIXEL_SHADER_ROOT_ACCESS
    //  ALLOW_STREAM_OUTPUT
    //  LOCAL_ROOT_SIGNATURE

    HRESULT hr = S_OK;
    TokenType Token;

    IFC(GetAndMatchToken(Token, TokenType::RootFlags));
    IFC(GetAndMatchToken(Token, TokenType::LParen));

    Flags = DxilRootSignatureFlags::None;

    Token = m_pTokenizer->PeekToken();
    if(Token.GetType() == TokenType::NumberU32)
    {
        IFC(GetAndMatchToken(Token, TokenType::NumberU32));
        uint32_t n = Token.GetU32Value();
        if(n != 0)
        {
            IFC(Error(ERR_RS_UNEXPECTED_TOKEN, "Root signature flag values can only be 0 or flag enum values, found: '%s'", Token.GetStr()));
        }
    }
    else
    {
        for(;;)
        {
            Token = m_pTokenizer->GetToken();
            switch(Token.GetType())
            {
            case TokenType::ALLOW_INPUT_ASSEMBLER_INPUT_LAYOUT:
                Flags |= DxilRootSignatureFlags::AllowInputAssemblerInputLayout;
                break;
            case TokenType::DENY_VERTEX_SHADER_ROOT_ACCESS:
                Flags |= DxilRootSignatureFlags::DenyVertexShaderRootAccess;
                break;
            case TokenType::DENY_HULL_SHADER_ROOT_ACCESS:
                Flags |= DxilRootSignatureFlags::DenyHullShaderRootAccess;
                break;
            case TokenType::DENY_DOMAIN_SHADER_ROOT_ACCESS:
                Flags |= DxilRootSignatureFlags::DenyDomainShaderRootAccess;
                break;
            case TokenType::DENY_GEOMETRY_SHADER_ROOT_ACCESS:
                Flags |= DxilRootSignatureFlags::DenyGeometryShaderRootAccess;
                break;
            case TokenType::DENY_PIXEL_SHADER_ROOT_ACCESS:
                Flags |= DxilRootSignatureFlags::DenyPixelShaderRootAccess;
                break;
            case TokenType::ALLOW_STREAM_OUTPUT:
                Flags |= DxilRootSignatureFlags::AllowStreamOutput;
                break;
            case TokenType::LOCAL_ROOT_SIGNATURE:
                if ((bool)(m_CompilationFlags & DxilRootSignatureCompilationFlags::GlobalRootSignature))
                  IFC(Error(ERR_RS_LOCAL_FLAG_ON_GLOBAL, "LOCAL_ROOT_SIGNATURE flag used in global root signature"));
                Flags |= DxilRootSignatureFlags::LocalRootSignature;
                break;
            default:
                IFC(Error(ERR_RS_UNEXPECTED_TOKEN, "Expected a root signature flag value, found: '%s'", Token.GetStr()));
            }

            Token = m_pTokenizer->PeekToken();
            if(Token.GetType() == TokenType::RParen)
                break;

            IFC(GetAndMatchToken(Token, TokenType::OR));
        }
    }

    IFC(GetAndMatchToken(Token, TokenType::RParen));

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::ParseRootConstants(DxilRootParameter1 &P)
{
    //"RootConstants(num32BitConstants=3, b2 [, space=1, visibility=SHADER_VISIBILITY_ALL ] ), "
    HRESULT hr = S_OK;
    TokenType Token;
    memset(&P, 0, sizeof(P));
    DXASSERT(P.ShaderVisibility == DxilShaderVisibility::All, "else default isn't zero");
    P.ParameterType = DxilRootParameterType::Constants32Bit;
    bool bSeenNum32BitConstants = false;
    bool bSeenBReg = false;
    bool bSeenSpace = false;
    bool bSeenVisibility = false;

    IFC(GetAndMatchToken(Token, TokenType::RootConstants));
    IFC(GetAndMatchToken(Token, TokenType::LParen));

    for(;;)
    {
        Token = m_pTokenizer->PeekToken();

        switch(Token.GetType())
        {
        case TokenType::num32BitConstants:
            IFC(MarkParameter(bSeenNum32BitConstants, "num32BitConstants"));
            IFC(ParseNum32BitConstants(P.Constants.Num32BitValues));
            break;
        case TokenType::BReg:
            IFC(MarkParameter(bSeenBReg, "cbuffer register b#"));
            IFC(ParseRegister(TokenType::BReg, P.Constants.ShaderRegister));
            break;
        case TokenType::space:
            IFC(MarkParameter(bSeenSpace, "space"));
            IFC(ParseSpace(P.Constants.RegisterSpace));
            break;
        case TokenType::visibility:
            IFC(MarkParameter(bSeenVisibility, "visibility"));
            IFC(ParseVisibility(P.ShaderVisibility));
            break;
        default:
            IFC(Error(ERR_RS_UNEXPECTED_TOKEN, "Unexpected token '%s'", Token.GetStr()));
            break;
        }

        Token = m_pTokenizer->GetToken();
        if(Token.GetType() == TokenType::RParen)
            break;
        else if(Token.GetType() != TokenType::Comma)
            IFC(Error(ERR_RS_UNEXPECTED_TOKEN, "Unexpected token '%s'", Token.GetStr()));
    }

    if(!bSeenNum32BitConstants)
    {
        IFC(Error(ERR_RS_UNDEFINED_REGISTER, "num32BitConstants must be defined for each RootConstants"));
    }
    if(!bSeenBReg)
    {
        IFC(Error(ERR_RS_UNDEFINED_REGISTER, "Constant buffer register b# must be defined for each RootConstants"));
    }

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::ParseRootShaderResource(TokenType::Type TokType, 
                                                     TokenType::Type RegType,
                                                     DxilRootParameterType ResType,
                                                     DxilRootParameter1 &P)
{
    // CBV(b0 [, space=3, flags=0, visibility=VISIBILITY_ALL] )
    HRESULT hr = S_OK;
    TokenType Token;
    P.ParameterType = ResType;
    P.ShaderVisibility = DxilShaderVisibility::All;
    P.Descriptor.ShaderRegister = 0;
    P.Descriptor.RegisterSpace = 0;
    P.Descriptor.Flags = DxilRootDescriptorFlags::None;
    bool bSeenReg           = false;
    bool bSeenFlags         = false;
    bool bSeenSpace         = false;
    bool bSeenVisibility    = false;

    IFC(GetAndMatchToken(Token, TokType));
    IFC(GetAndMatchToken(Token, TokenType::LParen));

    for(;;)
    {
        Token = m_pTokenizer->PeekToken();

        switch(Token.GetType())
        {
        case TokenType::BReg:
        case TokenType::TReg:
        case TokenType::UReg:
            IFC(MarkParameter(bSeenReg, "shader register"));
            IFC(ParseRegister(RegType, P.Descriptor.ShaderRegister));
            break;
        case TokenType::flags:
            IFC(MarkParameter(bSeenFlags, "flags"));
            IFC(ParseRootDescFlags(P.Descriptor.Flags));
            break;
        case TokenType::space:
            IFC(MarkParameter(bSeenSpace, "space"));
            IFC(ParseSpace(P.Descriptor.RegisterSpace));
            break;
        case TokenType::visibility:
            IFC(MarkParameter(bSeenVisibility, "visibility"));
            IFC(ParseVisibility(P.ShaderVisibility));
            break;
        default:
            IFC(Error(ERR_RS_UNEXPECTED_TOKEN, "Unexpected token '%s'", Token.GetStr()));
            break;
        }

        Token = m_pTokenizer->GetToken();
        if(Token.GetType() == TokenType::RParen)
            break;
        else if(Token.GetType() != TokenType::Comma)
            IFC(Error(ERR_RS_UNEXPECTED_TOKEN, "Unexpected token '%s'", Token.GetStr()));
    }

    if(!bSeenReg)
    {
        IFC(Error(ERR_RS_UNDEFINED_REGISTER, "shader register must be defined for each CBV/SRV/UAV"));
    }

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::ParseRootDescriptorTable(DxilRootParameter1 &P)
{
    //DescriptorTable( SRV(t2, numDescriptors = 6), UAV(u0, numDescriptors = 4) [, visibility = SHADER_VISIBILITY_ALL ] )
    HRESULT hr = S_OK;
    TokenType Token;
    memset(&P, 0, sizeof(P));
    DXASSERT(P.ShaderVisibility == DxilShaderVisibility::All, "else default isn't zero");
    P.ParameterType = DxilRootParameterType::DescriptorTable;
    bool bSeenVisibility = false;
    DxilDescriptorRange1 * pDescs = NULL;
    SmallVector<DxilDescriptorRange1, 4> Ranges;

    IFC(GetAndMatchToken(Token, TokenType::DescriptorTable));
    IFC(GetAndMatchToken(Token, TokenType::LParen));

    for(;;)
    {
        Token = m_pTokenizer->PeekToken();

        switch(Token.GetType())
        {
        case TokenType::CBV:
        {
            DxilDescriptorRange1 R;
            IFC(ParseDescTableResource(Token.GetType(), TokenType::BReg, DxilDescriptorRangeType::CBV, R));
            Ranges.push_back(R);
            break;
        }
        case TokenType::SRV:
        {
            DxilDescriptorRange1 R;
            IFC(ParseDescTableResource(Token.GetType(), TokenType::TReg, DxilDescriptorRangeType::SRV, R));
            Ranges.push_back(R);
            break;
        }
        case TokenType::UAV:
        {
            DxilDescriptorRange1 R;
            IFC(ParseDescTableResource(Token.GetType(), TokenType::UReg, DxilDescriptorRangeType::UAV, R));
            Ranges.push_back(R);
            break;
        }
        case TokenType::Sampler:
        {
            DxilDescriptorRange1 R;
            IFC(ParseDescTableResource(Token.GetType(), TokenType::SReg, DxilDescriptorRangeType::Sampler, R));
            Ranges.push_back(R);
            break;
        }
        case TokenType::visibility:
            IFC(MarkParameter(bSeenVisibility, "visibility"));
            IFC(ParseVisibility(P.ShaderVisibility));
            break;
        default:
            IFC(Error(ERR_RS_UNEXPECTED_TOKEN, "Unexpected token '%s'", Token.GetStr()));
            break;
        }

        Token = m_pTokenizer->GetToken();
        if(Token.GetType() == TokenType::RParen)
            break;
        else if(Token.GetType() != TokenType::Comma)
            IFC(Error(ERR_RS_UNEXPECTED_TOKEN, "Unexpected token '%s'", Token.GetStr()));
    }

    if(Ranges.size() > 0)
    {
        IFCOOM(pDescs = NEW DxilDescriptorRange1[Ranges.size()]);
        for(uint32_t i = 0; i < Ranges.size(); i++)
        {
            pDescs[i] = Ranges[i];
        }
        P.DescriptorTable.pDescriptorRanges = pDescs;
        P.DescriptorTable.NumDescriptorRanges = Ranges.size();
    }

Cleanup:
    if(FAILED(hr))
    {
        delete[] pDescs;
    }
    return hr;
}

HRESULT RootSignatureParser::ParseDescTableResource(TokenType::Type TokType, 
                                                    TokenType::Type RegType, 
                                                    DxilDescriptorRangeType RangeType, 
                                                    DxilDescriptorRange1 &R)
{
    HRESULT hr = S_OK;
    TokenType Token;
    // CBV(b0 [, numDescriptors = 1, space=0, flags=0, offset = DESCRIPTOR_RANGE_OFFSET_APPEND] )

    R.RangeType = RangeType;
    R.NumDescriptors = 1;
    R.BaseShaderRegister = 0;
    R.RegisterSpace = 0;
    R.Flags = DxilDescriptorRangeFlags::None;
    R.OffsetInDescriptorsFromTableStart = DxilDescriptorRangeOffsetAppend;
    bool bSeenReg               = false;
    bool bSeenNumDescriptors    = false;
    bool bSeenSpace             = false;
    bool bSeenFlags             = false;
    bool bSeenOffset            = false;

    IFC(GetAndMatchToken(Token, TokType));
    IFC(GetAndMatchToken(Token, TokenType::LParen));

    for(;;)
    {
        Token = m_pTokenizer->PeekToken();

        switch(Token.GetType())
        {
        case TokenType::BReg:
        case TokenType::TReg:
        case TokenType::UReg:
        case TokenType::SReg:
            IFC(MarkParameter(bSeenReg, "shader register"));
            IFC(ParseRegister(RegType, R.BaseShaderRegister));
            break;
        case TokenType::numDescriptors:
            IFC(MarkParameter(bSeenNumDescriptors, "numDescriptors"));
            IFC(ParseNumDescriptors(R.NumDescriptors));
            break;
        case TokenType::space:
            IFC(MarkParameter(bSeenSpace, "space"));
            IFC(ParseSpace(R.RegisterSpace));
            break;
        case TokenType::flags:
            IFC(MarkParameter(bSeenFlags, "flags"));
            IFC(ParseDescRangeFlags(RangeType, R.Flags));
            break;
        case TokenType::offset:
            IFC(MarkParameter(bSeenOffset, "offset"));
            IFC(ParseOffset(R.OffsetInDescriptorsFromTableStart));
            break;
        default:
            IFC(Error(ERR_RS_UNEXPECTED_TOKEN, "Unexpected token '%s'", Token.GetStr()));
            break;
        }

        Token = m_pTokenizer->GetToken();
        if(Token.GetType() == TokenType::RParen)
            break;
        else if(Token.GetType() != TokenType::Comma)
            IFC(Error(ERR_RS_UNEXPECTED_TOKEN, "Unexpected token '%s'", Token.GetStr()));
    }

    if(!bSeenReg)
    {
        IFC(Error(ERR_RS_UNDEFINED_REGISTER, "shader register must be defined for each CBV/SRV/UAV"));
    }

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::ParseRegister(TokenType::Type RegType, uint32_t & Reg)
{
    HRESULT hr = S_OK;
    TokenType Token = m_pTokenizer->PeekToken();

    switch(Token.GetType())
    {
    case TokenType::BReg:
        IFC(GetAndMatchToken(Token, TokenType::BReg));
        break;
    case TokenType::TReg:
        IFC(GetAndMatchToken(Token, TokenType::TReg));
        break;
    case TokenType::UReg:
        IFC(GetAndMatchToken(Token, TokenType::UReg));
        break;
    case TokenType::SReg:
        IFC(GetAndMatchToken(Token, TokenType::SReg));
        break;
    default:
        IFC(Error(ERR_RS_UNEXPECTED_TOKEN, "Expected a register token (CBV, SRV, UAV, Sampler), found: '%s'", Token.GetStr()));
    }

    if(Token.GetType() != RegType)
    {
        switch(RegType)
        {
        case TokenType::BReg:
            IFC(Error(ERR_RS_INCORRECT_REGISTER_TYPE, "Incorrect register type '%s' in CBV (expected b#)", Token.GetStr()));
            break;
        case TokenType::TReg:
            IFC(Error(ERR_RS_INCORRECT_REGISTER_TYPE, "Incorrect register type '%s' in SRV (expected t#)", Token.GetStr()));
            break;
        case TokenType::UReg:
            IFC(Error(ERR_RS_INCORRECT_REGISTER_TYPE, "Incorrect register type '%s' in UAV (expected u#)", Token.GetStr()));
            break;
        case TokenType::SReg:
            IFC(Error(ERR_RS_INCORRECT_REGISTER_TYPE, "Incorrect register type '%s' in Sampler/StaticSampler (expected s#)", Token.GetStr()));
            break;
        default:
          // Only Register types are relevant.
	  break;
        }
    }

    Reg = Token.GetU32Value();

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::ParseSpace(uint32_t & Space)
{
    HRESULT hr = S_OK;
    TokenType Token;

    IFC(GetAndMatchToken(Token, TokenType::space));
    IFC(GetAndMatchToken(Token, TokenType::EQ));
    IFC(GetAndMatchToken(Token, TokenType::NumberU32));
    Space = Token.GetU32Value();

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::ParseNumDescriptors(uint32_t & NumDescriptors)
{
    HRESULT hr = S_OK;
    TokenType Token;

    IFC(GetAndMatchToken(Token, TokenType::numDescriptors));
    IFC(GetAndMatchToken(Token, TokenType::EQ));
    Token = m_pTokenizer->PeekToken();
    if(Token.GetType() == TokenType::unbounded)
    {
        IFC(GetAndMatchToken(Token, TokenType::unbounded));
        NumDescriptors = UINT32_MAX;
    }
    else
    {
        IFC(GetAndMatchToken(Token, TokenType::NumberU32));
        NumDescriptors = Token.GetU32Value();
    }

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::ParseRootDescFlags(DxilRootDescriptorFlags &Flags)
{
    // flags=DATA_VOLATILE | DATA_STATIC | DATA_STATIC_WHILE_SET_AT_EXECUTE

    HRESULT hr = S_OK;
    TokenType Token;

    if (m_Version == DxilRootSignatureVersion::Version_1_0)
    {
        IFC(Error(ERR_RS_WRONG_ROOT_DESC_FLAG, "Root descriptor flags cannot be specified for root_sig_1_0"));
    }

    IFC(GetAndMatchToken(Token, TokenType::flags));
    IFC(GetAndMatchToken(Token, TokenType::EQ));

    Flags = DxilRootDescriptorFlags::None;

    Token = m_pTokenizer->PeekToken();
    if(Token.GetType() == TokenType::NumberU32)
    {
        IFC(GetAndMatchToken(Token, TokenType::NumberU32));
        uint32_t n = Token.GetU32Value();
        if(n != 0)
        {
            IFC(Error(ERR_RS_UNEXPECTED_TOKEN, "Root descriptor flag values can only be 0 or flag enum values, found: '%s'", Token.GetStr()));
        }
    }
    else
    {
        for(;;)
        {
            Token = m_pTokenizer->GetToken();
            switch(Token.GetType())
            {
            case TokenType::DATA_VOLATILE:
                Flags |= DxilRootDescriptorFlags::DataVolatile;
                break;
            case TokenType::DATA_STATIC:
                Flags |= DxilRootDescriptorFlags::DataStatic;
                break;
            case TokenType::DATA_STATIC_WHILE_SET_AT_EXECUTE:
                Flags |= DxilRootDescriptorFlags::DataStaticWhileSetAtExecute;
                break;
            default:
                IFC(Error(ERR_RS_UNEXPECTED_TOKEN, "Expected a root descriptor flag value, found: '%s'", Token.GetStr()));
            }

            Token = m_pTokenizer->PeekToken();
            if(Token.GetType() == TokenType::RParen || Token.GetType() == TokenType::Comma)
                break;

            IFC(GetAndMatchToken(Token, TokenType::OR));
        }
    }

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::ParseDescRangeFlags(DxilDescriptorRangeType,
                                                 DxilDescriptorRangeFlags & Flags)
{
    // flags=DESCRIPTORS_VOLATILE | DATA_VOLATILE | DATA_STATIC | DATA_STATIC_WHILE_SET_AT_EXECUTE | DESCRIPTORS_STATIC_KEEPING_BUFFER_BOUNDS_CHECKS

    HRESULT hr = S_OK;
    TokenType Token;

    if (m_Version == DxilRootSignatureVersion::Version_1_0)
    {
        IFC(Error(ERR_RS_WRONG_DESC_RANGE_FLAG, "Descriptor range flags cannot be specified for root_sig_1_0"));
    }

    IFC(GetAndMatchToken(Token, TokenType::flags));
    IFC(GetAndMatchToken(Token, TokenType::EQ));

    Flags = DxilDescriptorRangeFlags::None;

    Token = m_pTokenizer->PeekToken();
    if(Token.GetType() == TokenType::NumberU32)
    {
        IFC(GetAndMatchToken(Token, TokenType::NumberU32));
        uint32_t n = Token.GetU32Value();
        if(n != 0)
        {
            IFC(Error(ERR_RS_UNEXPECTED_TOKEN, "Descriptor range flag values can only be 0 or flag enum values, found: '%s'", Token.GetStr()));
        }
    }
    else
    {
        for(;;)
        {
            Token = m_pTokenizer->GetToken();
            switch(Token.GetType())
            {
            case TokenType::DESCRIPTORS_VOLATILE:
                Flags |= DxilDescriptorRangeFlags::DescriptorsVolatile;
                break;
            case TokenType::DATA_VOLATILE:
                Flags |= DxilDescriptorRangeFlags::DataVolatile;
                break;
            case TokenType::DATA_STATIC:
                Flags |= DxilDescriptorRangeFlags::DataStatic;
                break;
            case TokenType::DATA_STATIC_WHILE_SET_AT_EXECUTE:
                Flags |= DxilDescriptorRangeFlags::DataStaticWhileSetAtExecute;
                break;
            case TokenType::DESCRIPTORS_STATIC_KEEPING_BUFFER_BOUNDS_CHECKS:
                Flags |= DxilDescriptorRangeFlags::DescriptorsStaticKeepingBufferBoundsChecks;
                break;
            default:
                IFC(Error(ERR_RS_UNEXPECTED_TOKEN, "Expected a descriptor range flag value, found: '%s'", Token.GetStr()));
            }

            Token = m_pTokenizer->PeekToken();
            if(Token.GetType() == TokenType::RParen || Token.GetType() == TokenType::Comma)
                break;

            IFC(GetAndMatchToken(Token, TokenType::OR));
        }
    }

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::ParseOffset(uint32_t & Offset)
{
    HRESULT hr = S_OK;
    TokenType Token;

    IFC(GetAndMatchToken(Token, TokenType::offset));
    IFC(GetAndMatchToken(Token, TokenType::EQ));
    Token = m_pTokenizer->PeekToken();
    if(Token.GetType() == TokenType::DESCRIPTOR_RANGE_OFFSET_APPEND)
    {
        IFC(GetAndMatchToken(Token, TokenType::DESCRIPTOR_RANGE_OFFSET_APPEND));
        Offset = DxilDescriptorRangeOffsetAppend;
    }
    else
    {
        IFC(GetAndMatchToken(Token, TokenType::NumberU32));
        Offset = Token.GetU32Value();
    }

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::ParseVisibility(DxilShaderVisibility & Vis)
{
    HRESULT hr = S_OK;
    TokenType Token;

    IFC(GetAndMatchToken(Token, TokenType::visibility));
    IFC(GetAndMatchToken(Token, TokenType::EQ));
    Token = m_pTokenizer->GetToken();

    switch(Token.GetType())
    {
    case TokenType::SHADER_VISIBILITY_ALL:      Vis = DxilShaderVisibility::All;      break;
    case TokenType::SHADER_VISIBILITY_VERTEX:   Vis = DxilShaderVisibility::Vertex;   break;
    case TokenType::SHADER_VISIBILITY_HULL:     Vis = DxilShaderVisibility::Hull;     break;
    case TokenType::SHADER_VISIBILITY_DOMAIN:   Vis = DxilShaderVisibility::Domain;   break;
    case TokenType::SHADER_VISIBILITY_GEOMETRY: Vis = DxilShaderVisibility::Geometry; break;
    case TokenType::SHADER_VISIBILITY_PIXEL:    Vis = DxilShaderVisibility::Pixel;    break;
    default:
        IFC(Error(ERR_RS_UNEXPECTED_TOKEN, 
                 "Unexpected visibility value: '%s'.", Token.GetStr()));
    }

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::ParseNum32BitConstants(uint32_t & NumConst)
{
    HRESULT hr = S_OK;
    TokenType Token;

    IFC(GetAndMatchToken(Token, TokenType::num32BitConstants));
    IFC(GetAndMatchToken(Token, TokenType::EQ));
    IFC(GetAndMatchToken(Token, TokenType::NumberU32));
    NumConst = Token.GetU32Value();

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::ParseStaticSampler(DxilStaticSamplerDesc &P)
{
    // StaticSampler( s0,
    //                [ Filter = FILTER_ANISOTROPIC, 
    //                  AddressU = TEXTURE_ADDRESS_WRAP,
    //                  AddressV = TEXTURE_ADDRESS_WRAP,
    //                  AddressW = TEXTURE_ADDRESS_WRAP,
    //                  MipLODBias = 0,
    //                  MaxAnisotropy = 16,
    //                  ComparisonFunc = COMPARISON_LESS_EQUAL,
    //                  BorderColor = STATIC_BORDER_COLOR_OPAQUE_WHITE,
    //                  MinLOD = 0.f,
    //                  MaxLOD = 3.402823466e+38f
    //                  space = 0, 
    //                  visibility = SHADER_VISIBILITY_ALL ] )
    HRESULT hr = S_OK;
    TokenType Token;
    memset(&P, 0, sizeof(P));
    P.Filter = DxilFilter::ANISOTROPIC;
    P.AddressU = P.AddressV = P.AddressW = DxilTextureAddressMode::Wrap;
    P.MaxAnisotropy = 16;
    P.ComparisonFunc = DxilComparisonFunc::LessEqual;
    P.BorderColor = DxilStaticBorderColor::OpaqueWhite;
    P.MaxLOD = DxilFloat32Max;
    bool bSeenFilter            = false;
    bool bSeenAddressU          = false;
    bool bSeenAddressV          = false;
    bool bSeenAddressW          = false;
    bool bSeenMipLODBias        = false;
    bool bSeenMaxAnisotropy     = false;
    bool bSeenComparisonFunc    = false;
    bool bSeenBorderColor       = false;
    bool bSeenMinLOD            = false;
    bool bSeenMaxLOD            = false;
    bool bSeenSReg              = false;
    bool bSeenSpace             = false;
    bool bSeenVisibility        = false;

    IFC(GetAndMatchToken(Token, TokenType::StaticSampler));
    IFC(GetAndMatchToken(Token, TokenType::LParen));

    for(;;)
    {
        Token = m_pTokenizer->PeekToken();

        switch(Token.GetType())
        {
        case TokenType::filter:
            IFC(MarkParameter(bSeenFilter, "filter"));
            IFC(ParseFilter(P.Filter));
            break;
        case TokenType::addressU:
            IFC(MarkParameter(bSeenAddressU, "addressU"));
            IFC(ParseTextureAddressMode(P.AddressU));
            break;
        case TokenType::addressV:
            IFC(MarkParameter(bSeenAddressV, "addressV"));
            IFC(ParseTextureAddressMode(P.AddressV));
            break;
        case TokenType::addressW:
            IFC(MarkParameter(bSeenAddressW, "addressW"));
            IFC(ParseTextureAddressMode(P.AddressW));
            break;
        case TokenType::mipLODBias:
            IFC(MarkParameter(bSeenMipLODBias, "mipLODBias"));
            IFC(ParseMipLODBias(P.MipLODBias));
            break;
        case TokenType::maxAnisotropy:
            IFC(MarkParameter(bSeenMaxAnisotropy, "maxAnisotropy"));
            IFC(ParseMaxAnisotropy(P.MaxAnisotropy));
            break;
        case TokenType::comparisonFunc:
            IFC(MarkParameter(bSeenComparisonFunc, "comparisonFunc"));
            IFC(ParseComparisonFunction(P.ComparisonFunc));
            break;
        case TokenType::borderColor:
            IFC(MarkParameter(bSeenBorderColor, "borderColor"));
            IFC(ParseBorderColor(P.BorderColor));
            break;
        case TokenType::minLOD:
            IFC(MarkParameter(bSeenMinLOD, "minLOD"));
            IFC(ParseMinLOD(P.MinLOD));
            break;
        case TokenType::maxLOD:
            IFC(MarkParameter(bSeenMaxLOD, "maxLOD"));
            IFC(ParseMaxLOD(P.MaxLOD));
            break;
        case TokenType::SReg:
            IFC(MarkParameter(bSeenSReg, "sampler register s#"));
            IFC(ParseRegister(TokenType::SReg, P.ShaderRegister));
            break;
        case TokenType::space:
            IFC(MarkParameter(bSeenSpace, "space"));
            IFC(ParseSpace(P.RegisterSpace));
            break;
        case TokenType::visibility:
            IFC(MarkParameter(bSeenVisibility, "visibility"));
            IFC(ParseVisibility(P.ShaderVisibility));
            break;
        default:
            IFC(Error(ERR_RS_UNEXPECTED_TOKEN, "Unexpected token '%s'", Token.GetStr()));
            break;
        }

        Token = m_pTokenizer->GetToken();
        if(Token.GetType() == TokenType::RParen)
            break;
        else if(Token.GetType() != TokenType::Comma)
            IFC(Error(ERR_RS_UNEXPECTED_TOKEN, "Unexpected token '%s'", Token.GetStr()));
    }

    if(!bSeenSReg)
    {
        IFC(Error(ERR_RS_UNDEFINED_REGISTER, "Sampler register s# must be defined for each static sampler"));
    }

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::ParseFilter(DxilFilter & Filter)
{
    HRESULT hr = S_OK;
    TokenType Token;

    IFC(GetAndMatchToken(Token, TokenType::filter));
    IFC(GetAndMatchToken(Token, TokenType::EQ));
    Token = m_pTokenizer->GetToken();

    switch(Token.GetType())
    {
    case TokenType::FILTER_MIN_MAG_MIP_POINT:                           Filter = DxilFilter::MIN_MAG_MIP_POINT;                            break;
    case TokenType::FILTER_MIN_MAG_POINT_MIP_LINEAR:                    Filter = DxilFilter::MIN_MAG_POINT_MIP_LINEAR;                     break;
    case TokenType::FILTER_MIN_POINT_MAG_LINEAR_MIP_POINT:              Filter = DxilFilter::MIN_POINT_MAG_LINEAR_MIP_POINT;               break;
    case TokenType::FILTER_MIN_POINT_MAG_MIP_LINEAR:                    Filter = DxilFilter::MIN_POINT_MAG_MIP_LINEAR;                     break;
    case TokenType::FILTER_MIN_LINEAR_MAG_MIP_POINT:                    Filter = DxilFilter::MIN_LINEAR_MAG_MIP_POINT;                     break;
    case TokenType::FILTER_MIN_LINEAR_MAG_POINT_MIP_LINEAR:             Filter = DxilFilter::MIN_LINEAR_MAG_POINT_MIP_LINEAR;              break;
    case TokenType::FILTER_MIN_MAG_LINEAR_MIP_POINT:                    Filter = DxilFilter::MIN_MAG_LINEAR_MIP_POINT;                     break;
    case TokenType::FILTER_MIN_MAG_MIP_LINEAR:                          Filter = DxilFilter::MIN_MAG_MIP_LINEAR;                           break;
    case TokenType::FILTER_ANISOTROPIC:                                 Filter = DxilFilter::ANISOTROPIC;                                  break;
    case TokenType::FILTER_COMPARISON_MIN_MAG_MIP_POINT:                Filter = DxilFilter::COMPARISON_MIN_MAG_MIP_POINT;                 break;
    case TokenType::FILTER_COMPARISON_MIN_MAG_POINT_MIP_LINEAR:         Filter = DxilFilter::COMPARISON_MIN_MAG_POINT_MIP_LINEAR;          break;
    case TokenType::FILTER_COMPARISON_MIN_POINT_MAG_LINEAR_MIP_POINT:   Filter = DxilFilter::COMPARISON_MIN_POINT_MAG_LINEAR_MIP_POINT;    break;
    case TokenType::FILTER_COMPARISON_MIN_POINT_MAG_MIP_LINEAR:         Filter = DxilFilter::COMPARISON_MIN_POINT_MAG_MIP_LINEAR;          break;
    case TokenType::FILTER_COMPARISON_MIN_LINEAR_MAG_MIP_POINT:         Filter = DxilFilter::COMPARISON_MIN_LINEAR_MAG_MIP_POINT;          break;
    case TokenType::FILTER_COMPARISON_MIN_LINEAR_MAG_POINT_MIP_LINEAR:  Filter = DxilFilter::COMPARISON_MIN_LINEAR_MAG_POINT_MIP_LINEAR;   break;
    case TokenType::FILTER_COMPARISON_MIN_MAG_LINEAR_MIP_POINT:         Filter = DxilFilter::COMPARISON_MIN_MAG_LINEAR_MIP_POINT;          break;
    case TokenType::FILTER_COMPARISON_MIN_MAG_MIP_LINEAR:               Filter = DxilFilter::COMPARISON_MIN_MAG_MIP_LINEAR;                break;
    case TokenType::FILTER_COMPARISON_ANISOTROPIC:                      Filter = DxilFilter::COMPARISON_ANISOTROPIC;                       break;
    case TokenType::FILTER_MINIMUM_MIN_MAG_MIP_POINT:                   Filter = DxilFilter::MINIMUM_MIN_MAG_MIP_POINT;                    break;
    case TokenType::FILTER_MINIMUM_MIN_MAG_POINT_MIP_LINEAR:            Filter = DxilFilter::MINIMUM_MIN_MAG_POINT_MIP_LINEAR;             break;
    case TokenType::FILTER_MINIMUM_MIN_POINT_MAG_LINEAR_MIP_POINT:      Filter = DxilFilter::MINIMUM_MIN_POINT_MAG_LINEAR_MIP_POINT;       break;
    case TokenType::FILTER_MINIMUM_MIN_POINT_MAG_MIP_LINEAR:            Filter = DxilFilter::MINIMUM_MIN_POINT_MAG_MIP_LINEAR;             break;
    case TokenType::FILTER_MINIMUM_MIN_LINEAR_MAG_MIP_POINT:            Filter = DxilFilter::MINIMUM_MIN_LINEAR_MAG_MIP_POINT;             break;
    case TokenType::FILTER_MINIMUM_MIN_LINEAR_MAG_POINT_MIP_LINEAR:     Filter = DxilFilter::MINIMUM_MIN_LINEAR_MAG_POINT_MIP_LINEAR;      break;
    case TokenType::FILTER_MINIMUM_MIN_MAG_LINEAR_MIP_POINT:            Filter = DxilFilter::MINIMUM_MIN_MAG_LINEAR_MIP_POINT;             break;
    case TokenType::FILTER_MINIMUM_MIN_MAG_MIP_LINEAR:                  Filter = DxilFilter::MINIMUM_MIN_MAG_MIP_LINEAR;                   break;
    case TokenType::FILTER_MINIMUM_ANISOTROPIC:                         Filter = DxilFilter::MINIMUM_ANISOTROPIC;                          break;
    case TokenType::FILTER_MAXIMUM_MIN_MAG_MIP_POINT:                   Filter = DxilFilter::MAXIMUM_MIN_MAG_MIP_POINT;                    break;
    case TokenType::FILTER_MAXIMUM_MIN_MAG_POINT_MIP_LINEAR:            Filter = DxilFilter::MAXIMUM_MIN_MAG_POINT_MIP_LINEAR;             break;
    case TokenType::FILTER_MAXIMUM_MIN_POINT_MAG_LINEAR_MIP_POINT:      Filter = DxilFilter::MAXIMUM_MIN_POINT_MAG_LINEAR_MIP_POINT;       break;
    case TokenType::FILTER_MAXIMUM_MIN_POINT_MAG_MIP_LINEAR:            Filter = DxilFilter::MAXIMUM_MIN_POINT_MAG_MIP_LINEAR;             break;
    case TokenType::FILTER_MAXIMUM_MIN_LINEAR_MAG_MIP_POINT:            Filter = DxilFilter::MAXIMUM_MIN_LINEAR_MAG_MIP_POINT;             break;
    case TokenType::FILTER_MAXIMUM_MIN_LINEAR_MAG_POINT_MIP_LINEAR:     Filter = DxilFilter::MAXIMUM_MIN_LINEAR_MAG_POINT_MIP_LINEAR;      break;
    case TokenType::FILTER_MAXIMUM_MIN_MAG_LINEAR_MIP_POINT:            Filter = DxilFilter::MAXIMUM_MIN_MAG_LINEAR_MIP_POINT;             break;
    case TokenType::FILTER_MAXIMUM_MIN_MAG_MIP_LINEAR:                  Filter = DxilFilter::MAXIMUM_MIN_MAG_MIP_LINEAR;                   break;
    case TokenType::FILTER_MAXIMUM_ANISOTROPIC:                         Filter = DxilFilter::MAXIMUM_ANISOTROPIC;                          break;
    default:
        IFC(Error(ERR_RS_UNEXPECTED_TOKEN, 
                 "Unexpected filter value: '%s'.", Token.GetStr()));
    }

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::ParseTextureAddressMode(DxilTextureAddressMode & AddressMode)
{
    HRESULT hr = S_OK;
    TokenType Token = m_pTokenizer->GetToken();
    DXASSERT_NOMSG(Token.GetType() == TokenType::addressU || 
                   Token.GetType() == TokenType::addressV || 
                   Token.GetType() == TokenType::addressW);
    IFC(GetAndMatchToken(Token, TokenType::EQ));
    Token = m_pTokenizer->GetToken();

    switch(Token.GetType())
    {
    case TokenType::TEXTURE_ADDRESS_WRAP:           AddressMode = DxilTextureAddressMode::Wrap;       break;
    case TokenType::TEXTURE_ADDRESS_MIRROR:         AddressMode = DxilTextureAddressMode::Mirror;     break;
    case TokenType::TEXTURE_ADDRESS_CLAMP:          AddressMode = DxilTextureAddressMode::Clamp;      break;
    case TokenType::TEXTURE_ADDRESS_BORDER:         AddressMode = DxilTextureAddressMode::Border;     break;
    case TokenType::TEXTURE_ADDRESS_MIRROR_ONCE:    AddressMode = DxilTextureAddressMode::MirrorOnce; break;
    default:
        IFC(Error(ERR_RS_UNEXPECTED_TOKEN, 
                 "Unexpected texture address mode value: '%s'.", Token.GetStr()));
    }

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::ParseMipLODBias(float & MipLODBias)
{
    HRESULT hr = S_OK;
    TokenType Token;

    IFC(GetAndMatchToken(Token, TokenType::mipLODBias));
    IFC(GetAndMatchToken(Token, TokenType::EQ));
    IFC(ParseFloat(MipLODBias));

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::ParseMaxAnisotropy(uint32_t & MaxAnisotropy)
{
    HRESULT hr = S_OK;
    TokenType Token;

    IFC(GetAndMatchToken(Token, TokenType::maxAnisotropy));
    IFC(GetAndMatchToken(Token, TokenType::EQ));
    IFC(GetAndMatchToken(Token, TokenType::NumberU32));
    MaxAnisotropy = Token.GetU32Value();

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::ParseComparisonFunction(DxilComparisonFunc & ComparisonFunc)
{
    HRESULT hr = S_OK;
    TokenType Token;

    IFC(GetAndMatchToken(Token, TokenType::comparisonFunc));
    IFC(GetAndMatchToken(Token, TokenType::EQ));
    Token = m_pTokenizer->GetToken();

    switch(Token.GetType())
    {
    case TokenType::COMPARISON_NEVER:           ComparisonFunc = DxilComparisonFunc::Never;        break;
    case TokenType::COMPARISON_LESS:            ComparisonFunc = DxilComparisonFunc::Less;         break;
    case TokenType::COMPARISON_EQUAL:           ComparisonFunc = DxilComparisonFunc::Equal;        break;
    case TokenType::COMPARISON_LESS_EQUAL:      ComparisonFunc = DxilComparisonFunc::LessEqual;    break;
    case TokenType::COMPARISON_GREATER:         ComparisonFunc = DxilComparisonFunc::Greater;      break;
    case TokenType::COMPARISON_NOT_EQUAL:       ComparisonFunc = DxilComparisonFunc::NotEqual;     break;
    case TokenType::COMPARISON_GREATER_EQUAL:   ComparisonFunc = DxilComparisonFunc::GreaterEqual; break;
    case TokenType::COMPARISON_ALWAYS:          ComparisonFunc = DxilComparisonFunc::Always;       break;
    default:
        IFC(Error(ERR_RS_UNEXPECTED_TOKEN, 
                 "Unexpected texture address mode value: '%s'.", Token.GetStr()));
    }

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::ParseBorderColor(DxilStaticBorderColor & BorderColor)
{
    HRESULT hr = S_OK;
    TokenType Token;

    IFC(GetAndMatchToken(Token, TokenType::borderColor));
    IFC(GetAndMatchToken(Token, TokenType::EQ));
    Token = m_pTokenizer->GetToken();

    switch(Token.GetType())
    {
    case TokenType::STATIC_BORDER_COLOR_TRANSPARENT_BLACK:  BorderColor = DxilStaticBorderColor::TransparentBlack;  break;
    case TokenType::STATIC_BORDER_COLOR_OPAQUE_BLACK:       BorderColor = DxilStaticBorderColor::OpaqueBlack;       break;
    case TokenType::STATIC_BORDER_COLOR_OPAQUE_WHITE:       BorderColor = DxilStaticBorderColor::OpaqueWhite;       break;
    default:
        IFC(Error(ERR_RS_UNEXPECTED_TOKEN, 
                 "Unexpected texture address mode value: '%s'.", Token.GetStr()));
    }

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::ParseMinLOD(float & MinLOD)
{
    HRESULT hr = S_OK;
    TokenType Token;

    IFC(GetAndMatchToken(Token, TokenType::minLOD));
    IFC(GetAndMatchToken(Token, TokenType::EQ));
    IFC(ParseFloat(MinLOD));

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::ParseMaxLOD(float & MaxLOD)
{
    HRESULT hr = S_OK;
    TokenType Token;

    IFC(GetAndMatchToken(Token, TokenType::maxLOD));
    IFC(GetAndMatchToken(Token, TokenType::EQ));
    IFC(ParseFloat(MaxLOD));

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::ParseFloat(float & v)
{
    HRESULT hr = S_OK;
    TokenType Token = m_pTokenizer->GetToken();
    if(Token.GetType() == TokenType::NumberU32)
    {
        v = (float)Token.GetU32Value();
    }
    else if(Token.GetType() == TokenType::NumberI32)
    {
        v = (float)Token.GetI32Value();
    }
    else if(Token.GetType() == TokenType::NumberFloat)
    {
        v = Token.GetFloatValue();
    }
    else
    {
        IFC(Error(ERR_RS_UNEXPECTED_TOKEN, "Expected float, found token '%s'", Token.GetStr()));
    }

Cleanup:
    return hr;
}

HRESULT RootSignatureParser::MarkParameter(bool & bSeen, LPCSTR pName)
{
    HRESULT hr = S_OK;

    if(bSeen)
    {
        IFC(Error(ERR_RS_UNEXPECTED_TOKEN, "Parameter '%s' can be specified only once", pName));
    }

    bSeen = true;

Cleanup:
    return hr;
}

_Use_decl_annotations_
bool clang::ParseHLSLRootSignature(
    const char *pData, unsigned Len, hlsl::DxilRootSignatureVersion Ver,
    hlsl::DxilRootSignatureCompilationFlags Flags, hlsl::DxilVersionedRootSignatureDesc **ppDesc, 
    SourceLocation Loc, clang::DiagnosticsEngine &Diags) {
  *ppDesc = nullptr;
  std::string OSStr;
  llvm::raw_string_ostream OS(OSStr);
  hlsl::RootSignatureTokenizer RST(pData, Len);
  hlsl::RootSignatureParser RSP(&RST, Ver, Flags, OS);
  hlsl::DxilVersionedRootSignatureDesc *D = nullptr;
  if (SUCCEEDED(RSP.Parse(&D))) {
    *ppDesc = D;
    return true;
  }
  else {
    // Create diagnostic error message.
    OS.flush();
    if (OSStr.empty()) {
      Diags.Report(Loc, clang::diag::err_hlsl_rootsig) << "unexpected";
    }
    else {
      Diags.Report(Loc, clang::diag::err_hlsl_rootsig) << OSStr.c_str();
    }
    return false;
  }
}

_Use_decl_annotations_
void clang::ReportHLSLRootSigError(clang::DiagnosticsEngine &Diags,
                            clang::SourceLocation Loc, const char *pData,
                            unsigned Len) {
  Diags.Report(Loc, clang::diag::err_hlsl_rootsig) << StringRef(pData, Len);
  return;
}