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      1 //
      2 // Copyright (c) 2002-2013 The ANGLE Project Authors. All rights reserved.
      3 // Use of this source code is governed by a BSD-style license that can be
      4 // found in the LICENSE file.
      5 //
      6 #ifndef _COMPILER_INTERFACE_INCLUDED_
      7 #define _COMPILER_INTERFACE_INCLUDED_
      8 
      9 #if defined(COMPONENT_BUILD) && !defined(ANGLE_TRANSLATOR_STATIC)
     10 #if defined(_WIN32) || defined(_WIN64)
     11 
     12 #if defined(ANGLE_TRANSLATOR_IMPLEMENTATION)
     13 #define COMPILER_EXPORT __declspec(dllexport)
     14 #else
     15 #define COMPILER_EXPORT __declspec(dllimport)
     16 #endif  // defined(ANGLE_TRANSLATOR_IMPLEMENTATION)
     17 
     18 #else  // defined(_WIN32) || defined(_WIN64)
     19 #define COMPILER_EXPORT __attribute__((visibility("default")))
     20 #endif
     21 
     22 #else  // defined(COMPONENT_BUILD) && !defined(ANGLE_TRANSLATOR_STATIC)
     23 #define COMPILER_EXPORT
     24 #endif
     25 
     26 #include <stddef.h>
     27 
     28 #include "KHR/khrplatform.h"
     29 
     30 //
     31 // This is the platform independent interface between an OGL driver
     32 // and the shading language compiler.
     33 //
     34 
     35 namespace sh
     36 {
     37 // GLenum alias
     38 typedef unsigned int GLenum;
     39 }
     40 
     41 // Must be included after GLenum proxy typedef
     42 // Note: make sure to increment ANGLE_SH_VERSION when changing ShaderVars.h
     43 #include "ShaderVars.h"
     44 
     45 #ifdef __cplusplus
     46 extern "C" {
     47 #endif
     48 
     49 // Version number for shader translation API.
     50 // It is incremented every time the API changes.
     51 #define ANGLE_SH_VERSION 130
     52 
     53 typedef enum {
     54   SH_GLES2_SPEC = 0x8B40,
     55   SH_WEBGL_SPEC = 0x8B41,
     56 
     57   // The CSS Shaders spec is a subset of the WebGL spec.
     58   //
     59   // In both CSS vertex and fragment shaders, ANGLE:
     60   // (1) Reserves the "css_" prefix.
     61   // (2) Renames the main function to css_main.
     62   // (3) Disables the gl_MaxDrawBuffers built-in.
     63   //
     64   // In CSS fragment shaders, ANGLE:
     65   // (1) Disables the gl_FragColor built-in.
     66   // (2) Disables the gl_FragData built-in.
     67   // (3) Enables the css_MixColor built-in.
     68   // (4) Enables the css_ColorMatrix built-in.
     69   //
     70   // After passing a CSS shader through ANGLE, the browser is expected to append
     71   // a new main function to it.
     72   // This new main function will call the css_main function.
     73   // It may also perform additional operations like varying assignment, texture
     74   // access, and gl_FragColor assignment in order to implement the CSS Shaders
     75   // blend modes.
     76   //
     77   SH_CSS_SHADERS_SPEC = 0x8B42
     78 } ShShaderSpec;
     79 
     80 typedef enum {
     81   SH_ESSL_OUTPUT   = 0x8B45,
     82   SH_GLSL_OUTPUT   = 0x8B46,
     83   SH_HLSL_OUTPUT   = 0x8B47,
     84   SH_HLSL9_OUTPUT  = 0x8B47,
     85   SH_HLSL11_OUTPUT = 0x8B48
     86 } ShShaderOutput;
     87 
     88 typedef enum {
     89   SH_PRECISION_HIGHP     = 0x5001,
     90   SH_PRECISION_MEDIUMP   = 0x5002,
     91   SH_PRECISION_LOWP      = 0x5003,
     92   SH_PRECISION_UNDEFINED = 0
     93 } ShPrecisionType;
     94 
     95 typedef enum {
     96   SH_INFO_LOG_LENGTH                = 0x8B84,
     97   SH_OBJECT_CODE_LENGTH             = 0x8B88,  // GL_SHADER_SOURCE_LENGTH
     98   SH_ACTIVE_UNIFORMS                = 0x8B86,
     99   SH_ACTIVE_UNIFORM_MAX_LENGTH      = 0x8B87,
    100   SH_ACTIVE_ATTRIBUTES              = 0x8B89,
    101   SH_ACTIVE_ATTRIBUTE_MAX_LENGTH    = 0x8B8A,
    102   SH_VARYINGS                       = 0x8BBB,
    103   SH_VARYING_MAX_LENGTH             = 0x8BBC,
    104   SH_MAPPED_NAME_MAX_LENGTH         = 0x6000,
    105   SH_NAME_MAX_LENGTH                = 0x6001,
    106   SH_HASHED_NAME_MAX_LENGTH         = 0x6002,
    107   SH_HASHED_NAMES_COUNT             = 0x6003,
    108   SH_SHADER_VERSION                 = 0x6004,
    109   SH_RESOURCES_STRING_LENGTH        = 0x6005,
    110   SH_OUTPUT_TYPE                    = 0x6006
    111 } ShShaderInfo;
    112 
    113 // Compile options.
    114 typedef enum {
    115   SH_VALIDATE                = 0,
    116   SH_VALIDATE_LOOP_INDEXING  = 0x0001,
    117   SH_INTERMEDIATE_TREE       = 0x0002,
    118   SH_OBJECT_CODE             = 0x0004,
    119   SH_VARIABLES               = 0x0008,
    120   SH_LINE_DIRECTIVES         = 0x0010,
    121   SH_SOURCE_PATH             = 0x0020,
    122   SH_UNROLL_FOR_LOOP_WITH_INTEGER_INDEX = 0x0040,
    123   // If a sampler array index happens to be a loop index,
    124   //   1) if its type is integer, unroll the loop.
    125   //   2) if its type is float, fail the shader compile.
    126   // This is to work around a mac driver bug.
    127   SH_UNROLL_FOR_LOOP_WITH_SAMPLER_ARRAY_INDEX = 0x0080,
    128 
    129   // This is needed only as a workaround for certain OpenGL driver bugs.
    130   SH_EMULATE_BUILT_IN_FUNCTIONS = 0x0100,
    131 
    132   // This is an experimental flag to enforce restrictions that aim to prevent
    133   // timing attacks.
    134   // It generates compilation errors for shaders that could expose sensitive
    135   // texture information via the timing channel.
    136   // To use this flag, you must compile the shader under the WebGL spec
    137   // (using the SH_WEBGL_SPEC flag).
    138   SH_TIMING_RESTRICTIONS = 0x0200,
    139 
    140   // This flag prints the dependency graph that is used to enforce timing
    141   // restrictions on fragment shaders.
    142   // This flag only has an effect if all of the following are true:
    143   // - The shader spec is SH_WEBGL_SPEC.
    144   // - The compile options contain the SH_TIMING_RESTRICTIONS flag.
    145   // - The shader type is GL_FRAGMENT_SHADER.
    146   SH_DEPENDENCY_GRAPH = 0x0400,
    147 
    148   // Enforce the GLSL 1.017 Appendix A section 7 packing restrictions.
    149   // This flag only enforces (and can only enforce) the packing
    150   // restrictions for uniform variables in both vertex and fragment
    151   // shaders. ShCheckVariablesWithinPackingLimits() lets embedders
    152   // enforce the packing restrictions for varying variables during
    153   // program link time.
    154   SH_ENFORCE_PACKING_RESTRICTIONS = 0x0800,
    155 
    156   // This flag ensures all indirect (expression-based) array indexing
    157   // is clamped to the bounds of the array. This ensures, for example,
    158   // that you cannot read off the end of a uniform, whether an array
    159   // vec234, or mat234 type. The ShArrayIndexClampingStrategy enum,
    160   // specified in the ShBuiltInResources when constructing the
    161   // compiler, selects the strategy for the clamping implementation.
    162   SH_CLAMP_INDIRECT_ARRAY_BOUNDS = 0x1000,
    163 
    164   // This flag limits the complexity of an expression.
    165   SH_LIMIT_EXPRESSION_COMPLEXITY = 0x2000,
    166 
    167   // This flag limits the depth of the call stack.
    168   SH_LIMIT_CALL_STACK_DEPTH = 0x4000,
    169 
    170   // This flag initializes gl_Position to vec4(0,0,0,0) at the
    171   // beginning of the vertex shader's main(), and has no effect in the
    172   // fragment shader. It is intended as a workaround for drivers which
    173   // incorrectly fail to link programs if gl_Position is not written.
    174   SH_INIT_GL_POSITION = 0x8000,
    175 
    176   // This flag replaces
    177   //   "a && b" with "a ? b : false",
    178   //   "a || b" with "a ? true : b".
    179   // This is to work around a MacOSX driver bug that |b| is executed
    180   // independent of |a|'s value.
    181   SH_UNFOLD_SHORT_CIRCUIT = 0x10000,
    182 
    183   // This flag initializes varyings without static use in vertex shader
    184   // at the beginning of main(), and has no effects in the fragment shader.
    185   // It is intended as a workaround for drivers which incorrectly optimize
    186   // out such varyings and cause a link failure.
    187   SH_INIT_VARYINGS_WITHOUT_STATIC_USE = 0x20000,
    188 
    189   // This flag scalarizes vec/ivec/bvec/mat constructor args.
    190   // It is intended as a workaround for Linux/Mac driver bugs.
    191   SH_SCALARIZE_VEC_AND_MAT_CONSTRUCTOR_ARGS = 0x40000,
    192 
    193   // This flag overwrites a struct name with a unique prefix.
    194   // It is intended as a workaround for drivers that do not handle
    195   // struct scopes correctly, including all Mac drivers and Linux AMD.
    196   SH_REGENERATE_STRUCT_NAMES = 0x80000,
    197 } ShCompileOptions;
    198 
    199 // Defines alternate strategies for implementing array index clamping.
    200 typedef enum {
    201   // Use the clamp intrinsic for array index clamping.
    202   SH_CLAMP_WITH_CLAMP_INTRINSIC = 1,
    203 
    204   // Use a user-defined function for array index clamping.
    205   SH_CLAMP_WITH_USER_DEFINED_INT_CLAMP_FUNCTION
    206 } ShArrayIndexClampingStrategy;
    207 
    208 //
    209 // Driver must call this first, once, before doing any other
    210 // compiler operations.
    211 // If the function succeeds, the return value is nonzero, else zero.
    212 //
    213 COMPILER_EXPORT int ShInitialize();
    214 //
    215 // Driver should call this at shutdown.
    216 // If the function succeeds, the return value is nonzero, else zero.
    217 //
    218 COMPILER_EXPORT int ShFinalize();
    219 
    220 // The 64 bits hash function. The first parameter is the input string; the
    221 // second parameter is the string length.
    222 typedef khronos_uint64_t (*ShHashFunction64)(const char*, size_t);
    223 
    224 //
    225 // Implementation dependent built-in resources (constants and extensions).
    226 // The names for these resources has been obtained by stripping gl_/GL_.
    227 //
    228 typedef struct
    229 {
    230     // Constants.
    231     int MaxVertexAttribs;
    232     int MaxVertexUniformVectors;
    233     int MaxVaryingVectors;
    234     int MaxVertexTextureImageUnits;
    235     int MaxCombinedTextureImageUnits;
    236     int MaxTextureImageUnits;
    237     int MaxFragmentUniformVectors;
    238     int MaxDrawBuffers;
    239 
    240     // Extensions.
    241     // Set to 1 to enable the extension, else 0.
    242     int OES_standard_derivatives;
    243     int OES_EGL_image_external;
    244     int ARB_texture_rectangle;
    245     int EXT_draw_buffers;
    246     int EXT_frag_depth;
    247     int EXT_shader_texture_lod;
    248 
    249     // Set to 1 if highp precision is supported in the fragment language.
    250     // Default is 0.
    251     int FragmentPrecisionHigh;
    252 
    253     // GLSL ES 3.0 constants.
    254     int MaxVertexOutputVectors;
    255     int MaxFragmentInputVectors;
    256     int MinProgramTexelOffset;
    257     int MaxProgramTexelOffset;
    258 
    259     // Name Hashing.
    260     // Set a 64 bit hash function to enable user-defined name hashing.
    261     // Default is NULL.
    262     ShHashFunction64 HashFunction;
    263 
    264     // Selects a strategy to use when implementing array index clamping.
    265     // Default is SH_CLAMP_WITH_CLAMP_INTRINSIC.
    266     ShArrayIndexClampingStrategy ArrayIndexClampingStrategy;
    267 
    268     // The maximum complexity an expression can be.
    269     int MaxExpressionComplexity;
    270 
    271     // The maximum depth a call stack can be.
    272     int MaxCallStackDepth;
    273 } ShBuiltInResources;
    274 
    275 //
    276 // Initialize built-in resources with minimum expected values.
    277 //
    278 COMPILER_EXPORT void ShInitBuiltInResources(ShBuiltInResources* resources);
    279 
    280 //
    281 // ShHandle held by but opaque to the driver.  It is allocated,
    282 // managed, and de-allocated by the compiler. Its contents
    283 // are defined by and used by the compiler.
    284 //
    285 // If handle creation fails, 0 will be returned.
    286 //
    287 typedef void* ShHandle;
    288 
    289 //
    290 // Returns the a concatenated list of the items in ShBuiltInResources as a string.
    291 // This function must be updated whenever ShBuiltInResources is changed.
    292 // Parameters:
    293 // handle: Specifies the handle of the compiler to be used.
    294 // outStringLen: Specifies the size of the buffer, in number of characters. The size
    295 //               of the buffer required to store the resources string can be obtained
    296 //               by calling ShGetInfo with SH_RESOURCES_STRING_LENGTH.
    297 // outStr: Returns a null-terminated string representing all the built-in resources.
    298 COMPILER_EXPORT void ShGetBuiltInResourcesString(const ShHandle handle, size_t outStringLen, char *outStr);
    299 
    300 //
    301 // Driver calls these to create and destroy compiler objects.
    302 //
    303 // Returns the handle of constructed compiler, null if the requested compiler is
    304 // not supported.
    305 // Parameters:
    306 // type: Specifies the type of shader - GL_FRAGMENT_SHADER or GL_VERTEX_SHADER.
    307 // spec: Specifies the language spec the compiler must conform to -
    308 //       SH_GLES2_SPEC or SH_WEBGL_SPEC.
    309 // output: Specifies the output code type - SH_ESSL_OUTPUT, SH_GLSL_OUTPUT,
    310 //         SH_HLSL9_OUTPUT or SH_HLSL11_OUTPUT.
    311 // resources: Specifies the built-in resources.
    312 COMPILER_EXPORT ShHandle ShConstructCompiler(
    313     sh::GLenum type,
    314     ShShaderSpec spec,
    315     ShShaderOutput output,
    316     const ShBuiltInResources* resources);
    317 COMPILER_EXPORT void ShDestruct(ShHandle handle);
    318 
    319 //
    320 // Compiles the given shader source.
    321 // If the function succeeds, the return value is nonzero, else zero.
    322 // Parameters:
    323 // handle: Specifies the handle of compiler to be used.
    324 // shaderStrings: Specifies an array of pointers to null-terminated strings
    325 //                containing the shader source code.
    326 // numStrings: Specifies the number of elements in shaderStrings array.
    327 // compileOptions: A mask containing the following parameters:
    328 // SH_VALIDATE: Validates shader to ensure that it conforms to the spec
    329 //              specified during compiler construction.
    330 // SH_VALIDATE_LOOP_INDEXING: Validates loop and indexing in the shader to
    331 //                            ensure that they do not exceed the minimum
    332 //                            functionality mandated in GLSL 1.0 spec,
    333 //                            Appendix A, Section 4 and 5.
    334 //                            There is no need to specify this parameter when
    335 //                            compiling for WebGL - it is implied.
    336 // SH_INTERMEDIATE_TREE: Writes intermediate tree to info log.
    337 //                       Can be queried by calling ShGetInfoLog().
    338 // SH_OBJECT_CODE: Translates intermediate tree to glsl or hlsl shader.
    339 //                 Can be queried by calling ShGetObjectCode().
    340 // SH_VARIABLES: Extracts attributes, uniforms, and varyings.
    341 //               Can be queried by calling ShGetVariableInfo().
    342 //
    343 COMPILER_EXPORT int ShCompile(
    344     const ShHandle handle,
    345     const char* const shaderStrings[],
    346     size_t numStrings,
    347     int compileOptions
    348     );
    349 
    350 // Returns a parameter from a compiled shader.
    351 // Parameters:
    352 // handle: Specifies the compiler
    353 // pname: Specifies the parameter to query.
    354 // The following parameters are defined:
    355 // SH_INFO_LOG_LENGTH: the number of characters in the information log
    356 //                     including the null termination character.
    357 // SH_OBJECT_CODE_LENGTH: the number of characters in the object code
    358 //                        including the null termination character.
    359 // SH_ACTIVE_ATTRIBUTES: the number of active attribute variables.
    360 // SH_ACTIVE_ATTRIBUTE_MAX_LENGTH: the length of the longest active attribute
    361 //                                 variable name including the null
    362 //                                 termination character.
    363 // SH_ACTIVE_UNIFORMS: the number of active uniform variables.
    364 // SH_ACTIVE_UNIFORM_MAX_LENGTH: the length of the longest active uniform
    365 //                               variable name including the null
    366 //                               termination character.
    367 // SH_VARYINGS: the number of varying variables.
    368 // SH_VARYING_MAX_LENGTH: the length of the longest varying variable name
    369 //                        including the null termination character.
    370 // SH_MAPPED_NAME_MAX_LENGTH: the length of the mapped variable name including
    371 //                            the null termination character.
    372 // SH_NAME_MAX_LENGTH: the max length of a user-defined name including the
    373 //                     null termination character.
    374 // SH_HASHED_NAME_MAX_LENGTH: the max length of a hashed name including the
    375 //                            null termination character.
    376 // SH_HASHED_NAMES_COUNT: the number of hashed names from the latest compile.
    377 // SH_SHADER_VERSION: the version of the shader language
    378 // SH_OUTPUT_TYPE: the currently set language output type
    379 //
    380 // params: Requested parameter
    381 COMPILER_EXPORT void ShGetInfo(const ShHandle handle,
    382                                ShShaderInfo pname,
    383                                size_t* params);
    384 
    385 // Returns nul-terminated information log for a compiled shader.
    386 // Parameters:
    387 // handle: Specifies the compiler
    388 // infoLog: Specifies an array of characters that is used to return
    389 //          the information log. It is assumed that infoLog has enough memory
    390 //          to accomodate the information log. The size of the buffer required
    391 //          to store the returned information log can be obtained by calling
    392 //          ShGetInfo with SH_INFO_LOG_LENGTH.
    393 COMPILER_EXPORT void ShGetInfoLog(const ShHandle handle, char* infoLog);
    394 
    395 // Returns null-terminated object code for a compiled shader.
    396 // Parameters:
    397 // handle: Specifies the compiler
    398 // infoLog: Specifies an array of characters that is used to return
    399 //          the object code. It is assumed that infoLog has enough memory to
    400 //          accomodate the object code. The size of the buffer required to
    401 //          store the returned object code can be obtained by calling
    402 //          ShGetInfo with SH_OBJECT_CODE_LENGTH.
    403 COMPILER_EXPORT void ShGetObjectCode(const ShHandle handle, char* objCode);
    404 
    405 // Returns information about a shader variable.
    406 // Parameters:
    407 // handle: Specifies the compiler
    408 // variableType: Specifies the variable type; options include
    409 //               SH_ACTIVE_ATTRIBUTES, SH_ACTIVE_UNIFORMS, SH_VARYINGS.
    410 // index: Specifies the index of the variable to be queried.
    411 // length: Returns the number of characters actually written in the string
    412 //         indicated by name (excluding the null terminator) if a value other
    413 //         than NULL is passed.
    414 // size: Returns the size of the variable.
    415 // type: Returns the data type of the variable.
    416 // precision: Returns the precision of the variable.
    417 // staticUse: Returns 1 if the variable is accessed in a statement after
    418 //            pre-processing, whether or not run-time flow of control will
    419 //            cause that statement to be executed.
    420 //            Returns 0 otherwise.
    421 // name: Returns a null terminated string containing the name of the
    422 //       variable. It is assumed that name has enough memory to accormodate
    423 //       the variable name. The size of the buffer required to store the
    424 //       variable name can be obtained by calling ShGetInfo with
    425 //       SH_ACTIVE_ATTRIBUTE_MAX_LENGTH, SH_ACTIVE_UNIFORM_MAX_LENGTH,
    426 //       SH_VARYING_MAX_LENGTH.
    427 // mappedName: Returns a null terminated string containing the mapped name of
    428 //             the variable, It is assumed that mappedName has enough memory
    429 //             (SH_MAPPED_NAME_MAX_LENGTH), or NULL if don't care about the
    430 //             mapped name. If the name is not mapped, then name and mappedName
    431 //             are the same.
    432 COMPILER_EXPORT void ShGetVariableInfo(const ShHandle handle,
    433                                        ShShaderInfo variableType,
    434                                        int index,
    435                                        size_t* length,
    436                                        int* size,
    437                                        sh::GLenum* type,
    438                                        ShPrecisionType* precision,
    439                                        int* staticUse,
    440                                        char* name,
    441                                        char* mappedName);
    442 
    443 // Returns information about a name hashing entry from the latest compile.
    444 // Parameters:
    445 // handle: Specifies the compiler
    446 // index: Specifies the index of the name hashing entry to be queried.
    447 // name: Returns a null terminated string containing the user defined name.
    448 //       It is assumed that name has enough memory to accomodate the name.
    449 //       The size of the buffer required to store the user defined name can
    450 //       be obtained by calling ShGetInfo with SH_NAME_MAX_LENGTH.
    451 // hashedName: Returns a null terminated string containing the hashed name of
    452 //             the uniform variable, It is assumed that hashedName has enough
    453 //             memory to accomodate the name. The size of the buffer required
    454 //             to store the name can be obtained by calling ShGetInfo with
    455 //             SH_HASHED_NAME_MAX_LENGTH.
    456 COMPILER_EXPORT void ShGetNameHashingEntry(const ShHandle handle,
    457                                            int index,
    458                                            char* name,
    459                                            char* hashedName);
    460 
    461 // Shader variable inspection.
    462 // Returns a pointer to a list of variables of the designated type.
    463 // (See ShaderVars.h for type definitions, included above)
    464 // Returns NULL on failure.
    465 // Parameters:
    466 // handle: Specifies the compiler
    467 COMPILER_EXPORT const std::vector<sh::Uniform> *ShGetUniforms(const ShHandle handle);
    468 COMPILER_EXPORT const std::vector<sh::Varying> *ShGetVaryings(const ShHandle handle);
    469 COMPILER_EXPORT const std::vector<sh::Attribute> *ShGetAttributes(const ShHandle handle);
    470 COMPILER_EXPORT const std::vector<sh::Attribute> *ShGetOutputVariables(const ShHandle handle);
    471 COMPILER_EXPORT const std::vector<sh::InterfaceBlock> *ShGetInterfaceBlocks(const ShHandle handle);
    472 
    473 typedef struct
    474 {
    475     sh::GLenum type;
    476     int size;
    477 } ShVariableInfo;
    478 
    479 // Returns 1 if the passed in variables pack in maxVectors following
    480 // the packing rules from the GLSL 1.017 spec, Appendix A, section 7.
    481 // Returns 0 otherwise. Also look at the SH_ENFORCE_PACKING_RESTRICTIONS
    482 // flag above.
    483 // Parameters:
    484 // maxVectors: the available rows of registers.
    485 // varInfoArray: an array of variable info (types and sizes).
    486 // varInfoArraySize: the size of the variable array.
    487 COMPILER_EXPORT int ShCheckVariablesWithinPackingLimits(
    488     int maxVectors,
    489     ShVariableInfo* varInfoArray,
    490     size_t varInfoArraySize);
    491 
    492 // Gives the compiler-assigned register for an interface block.
    493 // The method writes the value to the output variable "indexOut".
    494 // Returns true if it found a valid interface block, false otherwise.
    495 // Parameters:
    496 // handle: Specifies the compiler
    497 // interfaceBlockName: Specifies the interface block
    498 // indexOut: output variable that stores the assigned register
    499 COMPILER_EXPORT bool ShGetInterfaceBlockRegister(const ShHandle handle,
    500                                                  const char *interfaceBlockName,
    501                                                  unsigned int *indexOut);
    502 
    503 // Gives the compiler-assigned register for uniforms in the default
    504 // interface block.
    505 // The method writes the value to the output variable "indexOut".
    506 // Returns true if it found a valid default uniform, false otherwise.
    507 // Parameters:
    508 // handle: Specifies the compiler
    509 // interfaceBlockName: Specifies the uniform
    510 // indexOut: output variable that stores the assigned register
    511 COMPILER_EXPORT bool ShGetUniformRegister(const ShHandle handle,
    512                                           const char *uniformName,
    513                                           unsigned int *indexOut);
    514 
    515 #ifdef __cplusplus
    516 }
    517 #endif
    518 
    519 #endif // _COMPILER_INTERFACE_INCLUDED_
    520