path: root/src/mesa/main/shaderapi.c

/*
 * Mesa 3-D graphics library
 *
 * Copyright (C) 2004-2008  Brian Paul   All Rights Reserved.
 * Copyright (C) 2009-2010  VMware, Inc.  All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

/**
 * \file shaderapi.c
 * \author Brian Paul
 *
 * Implementation of GLSL-related API functions.
 * The glUniform* functions are in uniforms.c
 *
 *
 * XXX things to do:
 * 1. Check that the right error code is generated for all _mesa_error() calls.
 * 2. Insert FLUSH_VERTICES calls in various places
 */


#include <stdbool.h>
#include "main/glheader.h"
#include "main/context.h"
#include "main/dispatch.h"
#include "main/enums.h"
#include "main/hash.h"
#include "main/mtypes.h"
#include "main/pipelineobj.h"
#include "main/shaderapi.h"
#include "main/shaderobj.h"
#include "main/transformfeedback.h"
#include "main/uniforms.h"
#include "compiler/glsl/glsl_parser_extras.h"
#include "compiler/glsl/ir.h"
#include "compiler/glsl/ir_uniform.h"
#include "compiler/glsl/program.h"
#include "program/program.h"
#include "program/prog_print.h"
#include "program/prog_parameter.h"
#include "util/ralloc.h"
#include "util/hash_table.h"
#include "util/mesa-sha1.h"


/**
 * Return mask of GLSL_x flags by examining the MESA_GLSL env var.
 */
GLbitfield
_mesa_get_shader_flags(void)
{
   GLbitfield flags = 0x0;
   const char *env = getenv("MESA_GLSL");

   if (env) {
      if (strstr(env, "dump_on_error"))
         flags |= GLSL_DUMP_ON_ERROR;
      else if (strstr(env, "dump"))
         flags |= GLSL_DUMP;
      if (strstr(env, "log"))
         flags |= GLSL_LOG;
      if (strstr(env, "nopvert"))
         flags |= GLSL_NOP_VERT;
      if (strstr(env, "nopfrag"))
         flags |= GLSL_NOP_FRAG;
      if (strstr(env, "nopt"))
         flags |= GLSL_NO_OPT;
      else if (strstr(env, "opt"))
         flags |= GLSL_OPT;
      if (strstr(env, "uniform"))
         flags |= GLSL_UNIFORMS;
      if (strstr(env, "useprog"))
         flags |= GLSL_USE_PROG;
      if (strstr(env, "errors"))
         flags |= GLSL_REPORT_ERRORS;
   }

   return flags;
}


/**
 * Initialize context's shader state.
 */
void
_mesa_init_shader_state(struct gl_context *ctx)
{
   /* Device drivers may override these to control what kind of instructions
    * are generated by the GLSL compiler.
    */
   struct gl_shader_compiler_options options;
   gl_shader_stage sh;
   int i;

   memset(&options, 0, sizeof(options));
   options.MaxUnrollIterations = 32;
   options.MaxIfDepth = UINT_MAX;

   for (sh = 0; sh < MESA_SHADER_STAGES; ++sh)
      memcpy(&ctx->Const.ShaderCompilerOptions[sh], &options, sizeof(options));

   ctx->Shader.Flags = _mesa_get_shader_flags();

   if (ctx->Shader.Flags != 0)
      ctx->Const.GenerateTemporaryNames = true;

   /* Extended for ARB_separate_shader_objects */
   ctx->Shader.RefCount = 1;
   mtx_init(&ctx->Shader.Mutex, mtx_plain);

   ctx->TessCtrlProgram.patch_vertices = 3;
   for (i = 0; i < 4; ++i)
      ctx->TessCtrlProgram.patch_default_outer_level[i] = 1.0;
   for (i = 0; i < 2; ++i)
      ctx->TessCtrlProgram.patch_default_inner_level[i] = 1.0;
}


/**
 * Free the per-context shader-related state.
 */
void
_mesa_free_shader_state(struct gl_context *ctx)
{
   int i;
   for (i = 0; i < MESA_SHADER_STAGES; i++) {
      _mesa_reference_shader_program(ctx, &ctx->Shader.CurrentProgram[i],
                                     NULL);
   }
   _mesa_reference_shader_program(ctx, &ctx->Shader._CurrentFragmentProgram,
				  NULL);
   _mesa_reference_shader_program(ctx, &ctx->Shader.ActiveProgram, NULL);

   /* Extended for ARB_separate_shader_objects */
   _mesa_reference_pipeline_object(ctx, &ctx->_Shader, NULL);

   assert(ctx->Shader.RefCount == 1);
   mtx_destroy(&ctx->Shader.Mutex);
}


/**
 * Copy string from <src> to <dst>, up to maxLength characters, returning
 * length of <dst> in <length>.
 * \param src  the strings source
 * \param maxLength  max chars to copy
 * \param length  returns number of chars copied
 * \param dst  the string destination
 */
void
_mesa_copy_string(GLchar *dst, GLsizei maxLength,
                  GLsizei *length, const GLchar *src)
{
   GLsizei len;
   for (len = 0; len < maxLength - 1 && src && src[len]; len++)
      dst[len] = src[len];
   if (maxLength > 0)
      dst[len] = 0;
   if (length)
      *length = len;
}



/**
 * Confirm that the a shader type is valid and supported by the implementation
 *
 * \param ctx   Current GL context
 * \param type  Shader target
 *
 */
bool
_mesa_validate_shader_target(const struct gl_context *ctx, GLenum type)
{
   /* Note: when building built-in GLSL functions, this function may be
    * invoked with ctx == NULL.  In that case, we can only validate that it's
    * a shader target we recognize, not that it's supported in the current
    * context.  But that's fine--we don't need any further validation than
    * that when building built-in GLSL functions.
    */

   switch (type) {
   case GL_FRAGMENT_SHADER:
      return ctx == NULL || ctx->Extensions.ARB_fragment_shader;
   case GL_VERTEX_SHADER:
      return ctx == NULL || ctx->Extensions.ARB_vertex_shader;
   case GL_GEOMETRY_SHADER_ARB:
      return ctx == NULL || _mesa_has_geometry_shaders(ctx);
   case GL_TESS_CONTROL_SHADER:
   case GL_TESS_EVALUATION_SHADER:
      return ctx == NULL || _mesa_has_tessellation(ctx);
   case GL_COMPUTE_SHADER:
      return ctx == NULL || _mesa_has_compute_shaders(ctx);
   default:
      return false;
   }
}


static GLboolean
is_program(struct gl_context *ctx, GLuint name)
{
   struct gl_shader_program *shProg = _mesa_lookup_shader_program(ctx, name);
   return shProg ? GL_TRUE : GL_FALSE;
}


static GLboolean
is_shader(struct gl_context *ctx, GLuint name)
{
   struct gl_shader *shader = _mesa_lookup_shader(ctx, name);
   return shader ? GL_TRUE : GL_FALSE;
}


/**
 * Attach shader to a shader program.
 */
static void
attach_shader(struct gl_context *ctx, GLuint program, GLuint shader)
{
   struct gl_shader_program *shProg;
   struct gl_shader *sh;
   GLuint i, n;

   const bool same_type_disallowed = _mesa_is_gles(ctx);

   shProg = _mesa_lookup_shader_program_err(ctx, program, "glAttachShader");
   if (!shProg)
      return;

   sh = _mesa_lookup_shader_err(ctx, shader, "glAttachShader");
   if (!sh) {
      return;
   }

   n = shProg->NumShaders;
   for (i = 0; i < n; i++) {
      if (shProg->Shaders[i] == sh) {
         /* The shader is already attched to this program.  The
          * GL_ARB_shader_objects spec says:
          *
          *     "The error INVALID_OPERATION is generated by AttachObjectARB
          *     if <obj> is already attached to <containerObj>."
          */
         _mesa_error(ctx, GL_INVALID_OPERATION, "glAttachShader");
         return;
      } else if (same_type_disallowed &&
                 shProg->Shaders[i]->Type == sh->Type) {
        /* Shader with the same type is already attached to this program,
         * OpenGL ES 2.0 and 3.0 specs say:
         *
         *      "Multiple shader objects of the same type may not be attached
         *      to a single program object. [...] The error INVALID_OPERATION
         *      is generated if [...] another shader object of the same type
         *      as shader is already attached to program."
         */
         _mesa_error(ctx, GL_INVALID_OPERATION, "glAttachShader");
         return;
      }
   }

   /* grow list */
   shProg->Shaders = realloc(shProg->Shaders,
                             (n + 1) * sizeof(struct gl_shader *));
   if (!shProg->Shaders) {
      _mesa_error(ctx, GL_OUT_OF_MEMORY, "glAttachShader");
      return;
   }

   /* append */
   shProg->Shaders[n] = NULL; /* since realloc() didn't zero the new space */
   _mesa_reference_shader(ctx, &shProg->Shaders[n], sh);
   shProg->NumShaders++;
}


static GLuint
create_shader(struct gl_context *ctx, GLenum type)
{
   struct gl_shader *sh;
   GLuint name;

   if (!_mesa_validate_shader_target(ctx, type)) {
      _mesa_error(ctx, GL_INVALID_ENUM, "CreateShader(%s)",
                  _mesa_enum_to_string(type));
      return 0;
   }

   _mesa_HashLockMutex(ctx->Shared->ShaderObjects);
   name = _mesa_HashFindFreeKeyBlock(ctx->Shared->ShaderObjects, 1);
   sh = ctx->Driver.NewShader(ctx, name, type);
   _mesa_HashInsertLocked(ctx->Shared->ShaderObjects, name, sh);
   _mesa_HashUnlockMutex(ctx->Shared->ShaderObjects);

   return name;
}


static GLuint
create_shader_program(struct gl_context *ctx)
{
   GLuint name;
   struct gl_shader_program *shProg;

   _mesa_HashLockMutex(ctx->Shared->ShaderObjects);

   name = _mesa_HashFindFreeKeyBlock(ctx->Shared->ShaderObjects, 1);

   shProg = _mesa_new_shader_program(name);

   _mesa_HashInsertLocked(ctx->Shared->ShaderObjects, name, shProg);

   assert(shProg->RefCount == 1);

   _mesa_HashUnlockMutex(ctx->Shared->ShaderObjects);

   return name;
}


/**
 * Delete a shader program.  Actually, just decrement the program's
 * reference count and mark it as DeletePending.
 * Used to implement glDeleteProgram() and glDeleteObjectARB().
 */
static void
delete_shader_program(struct gl_context *ctx, GLuint name)
{
   /*
    * NOTE: deleting shaders/programs works a bit differently than
    * texture objects (and buffer objects, etc).  Shader/program
    * handles/IDs exist in the hash table until the object is really
    * deleted (refcount==0).  With texture objects, the handle/ID is
    * removed from the hash table in glDeleteTextures() while the tex
    * object itself might linger until its refcount goes to zero.
    */
   struct gl_shader_program *shProg;

   shProg = _mesa_lookup_shader_program_err(ctx, name, "glDeleteProgram");
   if (!shProg)
      return;

   if (!shProg->DeletePending) {
      shProg->DeletePending = GL_TRUE;

      /* effectively, decr shProg's refcount */
      _mesa_reference_shader_program(ctx, &shProg, NULL);
   }
}


static void
delete_shader(struct gl_context *ctx, GLuint shader)
{
   struct gl_shader *sh;

   sh = _mesa_lookup_shader_err(ctx, shader, "glDeleteShader");
   if (!sh)
      return;

   if (!sh->DeletePending) {
      sh->DeletePending = GL_TRUE;

      /* effectively, decr sh's refcount */
      _mesa_reference_shader(ctx, &sh, NULL);
   }
}


static void
detach_shader(struct gl_context *ctx, GLuint program, GLuint shader)
{
   struct gl_shader_program *shProg;
   GLuint n;
   GLuint i, j;

   shProg = _mesa_lookup_shader_program_err(ctx, program, "glDetachShader");
   if (!shProg)
      return;

   n = shProg->NumShaders;

   for (i = 0; i < n; i++) {
      if (shProg->Shaders[i]->Name == shader) {
         /* found it */
         struct gl_shader **newList;

         /* release */
         _mesa_reference_shader(ctx, &shProg->Shaders[i], NULL);

         /* alloc new, smaller array */
         newList = malloc((n - 1) * sizeof(struct gl_shader *));
         if (!newList) {
            _mesa_error(ctx, GL_OUT_OF_MEMORY, "glDetachShader");
            return;
         }
         /* Copy old list entries to new list, skipping removed entry at [i] */
         for (j = 0; j < i; j++) {
            newList[j] = shProg->Shaders[j];
         }
         while (++i < n) {
            newList[j++] = shProg->Shaders[i];
         }

         /* Free old list and install new one */
         free(shProg->Shaders);
         shProg->Shaders = newList;
         shProg->NumShaders = n - 1;

#ifdef DEBUG
         /* sanity check - make sure the new list's entries are sensible */
         for (j = 0; j < shProg->NumShaders; j++) {
            assert(shProg->Shaders[j]->Type == GL_VERTEX_SHADER ||
                   shProg->Shaders[j]->Type == GL_TESS_CONTROL_SHADER ||
                   shProg->Shaders[j]->Type == GL_TESS_EVALUATION_SHADER ||
                   shProg->Shaders[j]->Type == GL_GEOMETRY_SHADER ||
                   shProg->Shaders[j]->Type == GL_FRAGMENT_SHADER);
            assert(shProg->Shaders[j]->RefCount > 0);
         }
#endif

         return;
      }
   }

   /* not found */
   {
      GLenum err;
      if (is_shader(ctx, shader) || is_program(ctx, shader))
         err = GL_INVALID_OPERATION;
      else
         err = GL_INVALID_VALUE;
      _mesa_error(ctx, err, "glDetachShader(shader)");
      return;
   }
}


/**
 * Return list of shaders attached to shader program.
 */
static void
get_attached_shaders(struct gl_context *ctx, GLuint program, GLsizei maxCount,
                     GLsizei *count, GLuint *obj)
{
   struct gl_shader_program *shProg;

   if (maxCount < 0) {
      _mesa_error(ctx, GL_INVALID_VALUE, "glGetAttachedShaders(maxCount < 0)");
      return;
   }

   shProg =
      _mesa_lookup_shader_program_err(ctx, program, "glGetAttachedShaders");

   if (shProg) {
      GLuint i;
      for (i = 0; i < (GLuint) maxCount && i < shProg->NumShaders; i++) {
         obj[i] = shProg->Shaders[i]->Name;
      }
      if (count)
         *count = i;
   }
}


/**
 * glGetHandleARB() - return ID/name of currently bound shader program.
 */
static GLuint
get_handle(struct gl_context *ctx, GLenum pname)
{
   if (pname == GL_PROGRAM_OBJECT_ARB) {
      if (ctx->_Shader->ActiveProgram)
         return ctx->_Shader->ActiveProgram->Name;
      else
         return 0;
   }
   else {
      _mesa_error(ctx, GL_INVALID_ENUM, "glGetHandleARB");
      return 0;
   }
}


/**
 * Check if a geometry shader query is valid at this time.  If not, report an
 * error and return false.
 *
 * From GL 3.2 section 6.1.16 (Shader and Program Queries):
 *
 *     "If GEOMETRY_VERTICES_OUT, GEOMETRY_INPUT_TYPE, or GEOMETRY_OUTPUT_TYPE
 *     are queried for a program which has not been linked successfully, or
 *     which does not contain objects to form a geometry shader, then an
 *     INVALID_OPERATION error is generated."
 */
static bool
check_gs_query(struct gl_context *ctx, const struct gl_shader_program *shProg)
{
   if (shProg->LinkStatus &&
       shProg->_LinkedShaders[MESA_SHADER_GEOMETRY] != NULL) {
      return true;
   }

   _mesa_error(ctx, GL_INVALID_OPERATION,
               "glGetProgramv(linked geometry shader required)");
   return false;
}


/**
 * Check if a tessellation control shader query is valid at this time.
 * If not, report an error and return false.
 *
 * From GL 4.0 section 6.1.12 (Shader and Program Queries):
 *
 *     "If TESS_CONTROL_OUTPUT_VERTICES is queried for a program which has
 *     not been linked successfully, or which does not contain objects to
 *     form a tessellation control shader, then an INVALID_OPERATION error is
 *     generated."
 */
static bool
check_tcs_query(struct gl_context *ctx, const struct gl_shader_program *shProg)
{
   if (shProg->LinkStatus &&
       shProg->_LinkedShaders[MESA_SHADER_TESS_CTRL] != NULL) {
      return true;
   }

   _mesa_error(ctx, GL_INVALID_OPERATION,
               "glGetProgramv(linked tessellation control shader required)");
   return false;
}


/**
 * Check if a tessellation evaluation shader query is valid at this time.
 * If not, report an error and return false.
 *
 * From GL 4.0 section 6.1.12 (Shader and Program Queries):
 *
 *     "If any of the pname values in this paragraph are queried for a program
 *     which has not been linked successfully, or which does not contain
 *     objects to form a tessellation evaluation shader, then an
 *     INVALID_OPERATION error is generated."
 *
 */
static bool
check_tes_query(struct gl_context *ctx, const struct gl_shader_program *shProg)
{
   if (shProg->LinkStatus &&
       shProg->_LinkedShaders[MESA_SHADER_TESS_EVAL] != NULL) {
      return true;
   }

   _mesa_error(ctx, GL_INVALID_OPERATION, "glGetProgramv(linked tessellation "
               "evaluation shader required)");
   return false;
}


/**
 * glGetProgramiv() - get shader program state.
 * Note that this is for GLSL shader programs, not ARB vertex/fragment
 * programs (see glGetProgramivARB).
 */
static void
get_programiv(struct gl_context *ctx, GLuint program, GLenum pname,
              GLint *params)
{
   struct gl_shader_program *shProg
      = _mesa_lookup_shader_program_err(ctx, program, "glGetProgramiv(program)");

   /* Is transform feedback available in this context?
    */
   const bool has_xfb =
      (ctx->API == API_OPENGL_COMPAT && ctx->Extensions.EXT_transform_feedback)
      || ctx->API == API_OPENGL_CORE
      || _mesa_is_gles3(ctx);

   /* True if geometry shaders (of the form that was adopted into GLSL 1.50
    * and GL 3.2) are available in this context
    */
   const bool has_core_gs = _mesa_has_geometry_shaders(ctx);
   const bool has_tess = _mesa_has_tessellation(ctx);

   /* Are uniform buffer objects available in this context?
    */
   const bool has_ubo =
      (ctx->API == API_OPENGL_COMPAT &&
       ctx->Extensions.ARB_uniform_buffer_object)
      || ctx->API == API_OPENGL_CORE
      || _mesa_is_gles3(ctx);

   if (!shProg) {
      return;
   }

   switch (pname) {
   case GL_DELETE_STATUS:
      *params = shProg->DeletePending;
      return;
   case GL_LINK_STATUS:
      *params = shProg->LinkStatus;
      return;
   case GL_VALIDATE_STATUS:
      *params = shProg->Validated;
      return;
   case GL_INFO_LOG_LENGTH:
      *params = shProg->InfoLog ? strlen(shProg->InfoLog) + 1 : 0;
      return;
   case GL_ATTACHED_SHADERS:
      *params = shProg->NumShaders;
      return;
   case GL_ACTIVE_ATTRIBUTES:
      *params = _mesa_count_active_attribs(shProg);
      return;
   case GL_ACTIVE_ATTRIBUTE_MAX_LENGTH:
      *params = _mesa_longest_attribute_name_length(shProg);
      return;
   case GL_ACTIVE_UNIFORMS: {
      unsigned i;
      const unsigned num_uniforms =
         shProg->NumUniformStorage - shProg->NumHiddenUniforms;
      for (*params = 0, i = 0; i < num_uniforms; i++) {
         if (!shProg->UniformStorage[i].is_shader_storage)
            (*params)++;
      }
      return;
   }
   case GL_ACTIVE_UNIFORM_MAX_LENGTH: {
      unsigned i;
      GLint max_len = 0;
      const unsigned num_uniforms =
         shProg->NumUniformStorage - shProg->NumHiddenUniforms;

      for (i = 0; i < num_uniforms; i++) {
         if (shProg->UniformStorage[i].is_shader_storage)
            continue;

	 /* Add one for the terminating NUL character for a non-array, and
	  * 4 for the "[0]" and the NUL for an array.
	  */
	 const GLint len = strlen(shProg->UniformStorage[i].name) + 1 +
	     ((shProg->UniformStorage[i].array_elements != 0) ? 3 : 0);

	 if (len > max_len)
	    max_len = len;
      }

      *params = max_len;
      return;
   }
   case GL_TRANSFORM_FEEDBACK_VARYINGS:
      if (!has_xfb)
         break;
      *params = shProg->TransformFeedback.NumVarying;
      return;
   case GL_TRANSFORM_FEEDBACK_VARYING_MAX_LENGTH: {
      unsigned i;
      GLint max_len = 0;
      if (!has_xfb)
         break;

      for (i = 0; i < shProg->TransformFeedback.NumVarying; i++) {
         /* Add one for the terminating NUL character.
          */
         const GLint len =
            strlen(shProg->TransformFeedback.VaryingNames[i]) + 1;

         if (len > max_len)
            max_len = len;
      }

      *params = max_len;
      return;
   }
   case GL_TRANSFORM_FEEDBACK_BUFFER_MODE:
      if (!has_xfb)
         break;
      *params = shProg->TransformFeedback.BufferMode;
      return;
   case GL_GEOMETRY_VERTICES_OUT:
      if (!has_core_gs)
         break;
      if (check_gs_query(ctx, shProg))
         *params = shProg->Geom.VerticesOut;
      return;
   case GL_GEOMETRY_SHADER_INVOCATIONS:
      if (!has_core_gs || !ctx->Extensions.ARB_gpu_shader5)
         break;
      if (check_gs_query(ctx, shProg))
         *params = shProg->Geom.Invocations;
      return;
   case GL_GEOMETRY_INPUT_TYPE:
      if (!has_core_gs)
         break;
      if (check_gs_query(ctx, shProg))
         *params = shProg->Geom.InputType;
      return;
   case GL_GEOMETRY_OUTPUT_TYPE:
      if (!has_core_gs)
         break;
      if (check_gs_query(ctx, shProg))
         *params = shProg->Geom.OutputType;
      return;
   case GL_ACTIVE_UNIFORM_BLOCK_MAX_NAME_LENGTH: {
      unsigned i;
      GLint max_len = 0;

      if (!has_ubo)
         break;

      for (i = 0; i < shProg->NumUniformBlocks; i++) {
	 /* Add one for the terminating NUL character.
	  */
	 const GLint len = strlen(shProg->UniformBlocks[i].Name) + 1;

	 if (len > max_len)
	    max_len = len;
      }

      *params = max_len;
      return;
   }
   case GL_ACTIVE_UNIFORM_BLOCKS:
      if (!has_ubo)
         break;

      *params = shProg->NumUniformBlocks;
      return;
   case GL_PROGRAM_BINARY_RETRIEVABLE_HINT:
      /* This enum isn't part of the OES extension for OpenGL ES 2.0.  It is
       * only available with desktop OpenGL 3.0+ with the
       * GL_ARB_get_program_binary extension or OpenGL ES 3.0.
       *
       * On desktop, we ignore the 3.0+ requirement because it is silly.
       */
      if (!_mesa_is_desktop_gl(ctx) && !_mesa_is_gles3(ctx))
         break;

      *params = shProg->BinaryRetreivableHint;
      return;
   case GL_PROGRAM_BINARY_LENGTH:
      *params = 0;
      return;
   case GL_ACTIVE_ATOMIC_COUNTER_BUFFERS:
      if (!ctx->Extensions.ARB_shader_atomic_counters)
         break;

      *params = shProg->NumAtomicBuffers;
      return;
   case GL_COMPUTE_WORK_GROUP_SIZE: {
      int i;
      if (!_mesa_has_compute_shaders(ctx))
         break;
      if (!shProg->LinkStatus) {
         _mesa_error(ctx, GL_INVALID_OPERATION, "glGetProgramiv(program not "
                     "linked)");
         return;
      }
      if (shProg->_LinkedShaders[MESA_SHADER_COMPUTE] == NULL) {
         _mesa_error(ctx, GL_INVALID_OPERATION, "glGetProgramiv(no compute "
                     "shaders)");
         return;
      }
      for (i = 0; i < 3; i++)
         params[i] = shProg->Comp.LocalSize[i];
      return;
   }
   case GL_PROGRAM_SEPARABLE:
      /* If the program has not been linked, return initial value 0. */
      *params = (shProg->LinkStatus == GL_FALSE) ? 0 : shProg->SeparateShader;
      return;

   /* ARB_tessellation_shader */
   case GL_TESS_CONTROL_OUTPUT_VERTICES:
      if (!has_tess)
         break;
      if (check_tcs_query(ctx, shProg))
         *params = shProg->TessCtrl.VerticesOut;
      return;
   case GL_TESS_GEN_MODE:
      if (!has_tess)
         break;
      if (check_tes_query(ctx, shProg))
         *params = shProg->TessEval.PrimitiveMode;
      return;
   case GL_TESS_GEN_SPACING:
      if (!has_tess)
         break;
      if (check_tes_query(ctx, shProg))
         *params = shProg->TessEval.Spacing;
      return;
   case GL_TESS_GEN_VERTEX_ORDER:
      if (!has_tess)
         break;
      if (check_tes_query(ctx, shProg))
         *params = shProg->TessEval.VertexOrder;
      return;
   case GL_TESS_GEN_POINT_MODE:
      if (!has_tess)
         break;
      if (check_tes_query(ctx, shProg))
         *params = shProg->TessEval.PointMode;
      return;
   default:
      break;
   }

   _mesa_error(ctx, GL_INVALID_ENUM, "glGetProgramiv(pname=%s)",
               _mesa_enum_to_string(pname));
}


/**
 * glGetShaderiv() - get GLSL shader state
 */
static void
get_shaderiv(struct gl_context *ctx, GLuint name, GLenum pname, GLint *params)
{
   struct gl_shader *shader =
      _mesa_lookup_shader_err(ctx, name, "glGetShaderiv");

   if (!shader) {
      return;
   }

   switch (pname) {
   case GL_SHADER_TYPE:
      *params = shader->Type;
      break;
   case GL_DELETE_STATUS:
      *params = shader->DeletePending;
      break;
   case GL_COMPILE_STATUS:
      *params = shader->CompileStatus;
      break;
   case GL_INFO_LOG_LENGTH:
      *params = shader->InfoLog ? strlen(shader->InfoLog) + 1 : 0;
      break;
   case GL_SHADER_SOURCE_LENGTH:
      *params = shader->Source ? strlen((char *) shader->Source) + 1 : 0;
      break;
   default:
      _mesa_error(ctx, GL_INVALID_ENUM, "glGetShaderiv(pname)");
      return;
   }
}


static void
get_program_info_log(struct gl_context *ctx, GLuint program, GLsizei bufSize,
                     GLsizei *length, GLchar *infoLog)
{
   struct gl_shader_program *shProg;

   /* Section 2.5 GL Errors (page 18) of the OpenGL ES 3.0.4 spec and
    * section 2.3.1 (Errors) of the OpenGL 4.5 spec say:
    *
    *     "If a negative number is provided where an argument of type sizei or
    *     sizeiptr is specified, an INVALID_VALUE error is generated."
    */
   if (bufSize < 0) {
      _mesa_error(ctx, GL_INVALID_VALUE, "glGetProgramInfoLog(bufSize < 0)");
      return;
   }

   shProg = _mesa_lookup_shader_program_err(ctx, program,
                                            "glGetProgramInfoLog(program)");
   if (!shProg) {
      return;
   }

   _mesa_copy_string(infoLog, bufSize, length, shProg->InfoLog);
}


static void
get_shader_info_log(struct gl_context *ctx, GLuint shader, GLsizei bufSize,
                    GLsizei *length, GLchar *infoLog)
{
   struct gl_shader *sh;

   /* Section 2.5 GL Errors (page 18) of the OpenGL ES 3.0.4 spec and
    * section 2.3.1 (Errors) of the OpenGL 4.5 spec say:
    *
    *     "If a negative number is provided where an argument of type sizei or
    *     sizeiptr is specified, an INVALID_VALUE error is generated."
    */
   if (bufSize < 0) {
      _mesa_error(ctx, GL_INVALID_VALUE, "glGetShaderInfoLog(bufSize < 0)");
      return;
   }

   sh = _mesa_lookup_shader_err(ctx, shader, "glGetShaderInfoLog(shader)");
   if (!sh) {
      return;
   }

   _mesa_copy_string(infoLog, bufSize, length, sh->InfoLog);
}


/**
 * Return shader source code.
 */
static void
get_shader_source(struct gl_context *ctx, GLuint shader, GLsizei maxLength,
                  GLsizei *length, GLchar *sourceOut)
{
   struct gl_shader *sh;

   if (maxLength < 0) {
      _mesa_error(ctx, GL_INVALID_VALUE, "glGetShaderSource(bufSize < 0)");
      return;
   }

   sh = _mesa_lookup_shader_err(ctx, shader, "glGetShaderSource");
   if (!sh) {
      return;
   }
   _mesa_copy_string(sourceOut, maxLength, length, sh->Source);
}


/**
 * Set/replace shader source code.  A helper function used by
 * glShaderSource[ARB].
 */
static void
shader_source(struct gl_shader *sh, const GLchar *source)
{
   assert(sh);

   /* free old shader source string and install new one */
   free((void *)sh->Source);
   sh->Source = source;
#ifdef DEBUG
   sh->SourceChecksum = _mesa_str_checksum(sh->Source);
#endif
}


/**
 * Compile a shader.
 */
void
_mesa_compile_shader(struct gl_context *ctx, struct gl_shader *sh)
{
   if (!sh)
      return;

   if (!sh->Source) {
      /* If the user called glCompileShader without first calling
       * glShaderSource, we should fail to compile, but not raise a GL_ERROR.
       */
      sh->CompileStatus = GL_FALSE;
   } else {
      if (ctx->_Shader->Flags & GLSL_DUMP) {
         _mesa_log("GLSL source for %s shader %d:\n",
                 _mesa_shader_stage_to_string(sh->Stage), sh->Name);
         _mesa_log("%s\n", sh->Source);
      }

      /* this call will set the shader->CompileStatus field to indicate if
       * compilation was successful.
       */
      _mesa_glsl_compile_shader(ctx, sh, false, false);

      if (ctx->_Shader->Flags & GLSL_LOG) {
         _mesa_write_shader_to_file(sh);
      }

      if (ctx->_Shader->Flags & GLSL_DUMP) {
         if (sh->CompileStatus) {
            _mesa_log("GLSL IR for shader %d:\n", sh->Name);
            _mesa_print_ir(_mesa_get_log_file(), sh->ir, NULL);
            _mesa_log("\n\n");
         } else {
            _mesa_log("GLSL shader %d failed to compile.\n", sh->Name);
         }
         if (sh->InfoLog && sh->InfoLog[0] != 0) {
            _mesa_log("GLSL shader %d info log:\n", sh->Name);
            _mesa_log("%s\n", sh->InfoLog);
         }
      }
   }

   if (!sh->CompileStatus) {
      if (ctx->_Shader->Flags & GLSL_DUMP_ON_ERROR) {
         _mesa_log("GLSL source for %s shader %d:\n",
                 _mesa_shader_stage_to_string(sh->Stage), sh->Name);
         _mesa_log("%s\n", sh->Source);
         _mesa_log("Info Log:\n%s\n", sh->InfoLog);
      }

      if (ctx->_Shader->Flags & GLSL_REPORT_ERRORS) {
         _mesa_debug(ctx, "Error compiling shader %u:\n%s\n",
                     sh->Name, sh->InfoLog);
      }
   }
}


/**
 * Link a program's shaders.
 */
void
_mesa_link_program(struct gl_context *ctx, struct gl_shader_program *shProg)
{
   if (!shProg)
      return;

   /* From the ARB_transform_feedback2 specification:
    * "The error INVALID_OPERATION is generated by LinkProgram if <program> is
    *  the name of a program being used by one or more transform feedback
    *  objects, even if the objects are not currently bound or are paused."
    */
   if (_mesa_transform_feedback_is_using_program(ctx, shProg)) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "glLinkProgram(transform feedback is using the program)");
      return;
   }

   FLUSH_VERTICES(ctx, _NEW_PROGRAM);

   _mesa_glsl_link_shader(ctx, shProg);

   if (shProg->LinkStatus == GL_FALSE &&
       (ctx->_Shader->Flags & GLSL_REPORT_ERRORS)) {
      _mesa_debug(ctx, "Error linking program %u:\n%s\n",
                  shProg->Name, shProg->InfoLog);
   }

   /* debug code */
   if (0) {
      GLuint i;

      printf("Link %u shaders in program %u: %s\n",
                   shProg->NumShaders, shProg->Name,
                   shProg->LinkStatus ? "Success" : "Failed");

      for (i = 0; i < shProg->NumShaders; i++) {
         printf(" shader %u, type 0x%x\n",
                      shProg->Shaders[i]->Name,
                      shProg->Shaders[i]->Type);
      }
   }
}


/**
 * Print basic shader info (for debug).
 */
static void
print_shader_info(const struct gl_shader_program *shProg)
{
   GLuint i;

   printf("Mesa: glUseProgram(%u)\n", shProg->Name);
   for (i = 0; i < shProg->NumShaders; i++) {
      printf("  %s shader %u, checksum %u\n",
             _mesa_shader_stage_to_string(shProg->Shaders[i]->Stage),
	     shProg->Shaders[i]->Name,
	     shProg->Shaders[i]->SourceChecksum);
   }
   if (shProg->_LinkedShaders[MESA_SHADER_VERTEX])
      printf("  vert prog %u\n",
	     shProg->_LinkedShaders[MESA_SHADER_VERTEX]->Program->Id);
   if (shProg->_LinkedShaders[MESA_SHADER_FRAGMENT])
      printf("  frag prog %u\n",
	     shProg->_LinkedShaders[MESA_SHADER_FRAGMENT]->Program->Id);
   if (shProg->_LinkedShaders[MESA_SHADER_GEOMETRY])
      printf("  geom prog %u\n",
	     shProg->_LinkedShaders[MESA_SHADER_GEOMETRY]->Program->Id);
   if (shProg->_LinkedShaders[MESA_SHADER_TESS_CTRL])
      printf("  tesc prog %u\n",
	     shProg->_LinkedShaders[MESA_SHADER_TESS_CTRL]->Program->Id);
   if (shProg->_LinkedShaders[MESA_SHADER_TESS_EVAL])
      printf("  tese prog %u\n",
	     shProg->_LinkedShaders[MESA_SHADER_TESS_EVAL]->Program->Id);
}


/**
 * Use the named shader program for subsequent glUniform calls
 */
void
_mesa_active_program(struct gl_context *ctx, struct gl_shader_program *shProg,
		     const char *caller)
{
   if ((shProg != NULL) && !shProg->LinkStatus) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
		  "%s(program %u not linked)", caller, shProg->Name);
      return;
   }

   if (ctx->Shader.ActiveProgram != shProg) {
      _mesa_reference_shader_program(ctx, &ctx->Shader.ActiveProgram, shProg);
   }
}


static void
use_shader_program(struct gl_context *ctx, gl_shader_stage stage,
                   struct gl_shader_program *shProg,
                   struct gl_pipeline_object *shTarget)
{
   struct gl_shader_program **target;

   target = &shTarget->CurrentProgram[stage];
   if ((shProg != NULL) && (shProg->_LinkedShaders[stage] == NULL))
      shProg = NULL;

   if (*target != shProg) {
      /* Program is current, flush it */
      if (shTarget == ctx->_Shader) {
         FLUSH_VERTICES(ctx, _NEW_PROGRAM | _NEW_PROGRAM_CONSTANTS);
      }

      /* If the shader is also bound as the current rendering shader, unbind
       * it from that binding point as well.  This ensures that the correct
       * semantics of glDeleteProgram are maintained.
       */
      switch (stage) {
      case MESA_SHADER_VERTEX:
      case MESA_SHADER_TESS_CTRL:
      case MESA_SHADER_TESS_EVAL:
      case MESA_SHADER_GEOMETRY:
      case MESA_SHADER_COMPUTE:
         /* Empty for now. */
         break;
      case MESA_SHADER_FRAGMENT:
         if (*target == ctx->_Shader->_CurrentFragmentProgram) {
	    _mesa_reference_shader_program(ctx,
                                           &ctx->_Shader->_CurrentFragmentProgram,
					   NULL);
	 }
	 break;
      }

      _mesa_reference_shader_program(ctx, target, shProg);
      return;
   }
}


/**
 * Use the named shader program for subsequent rendering.
 */
void
_mesa_use_program(struct gl_context *ctx, struct gl_shader_program *shProg)
{
   int i;
   for (i = 0; i < MESA_SHADER_STAGES; i++)
      use_shader_program(ctx, i, shProg, &ctx->Shader);
   _mesa_active_program(ctx, shProg, "glUseProgram");

   _mesa_shader_program_init_subroutine_defaults(shProg);
   if (ctx->Driver.UseProgram)
      ctx->Driver.UseProgram(ctx, shProg);
}


/**
 * Do validation of the given shader program.
 * \param errMsg  returns error message if validation fails.
 * \return GL_TRUE if valid, GL_FALSE if invalid (and set errMsg)
 */
static GLboolean
validate_shader_program(const struct gl_shader_program *shProg,
                        char *errMsg)
{
   if (!shProg->LinkStatus) {
      return GL_FALSE;
   }

   /* From the GL spec, a program is invalid if any of these are true:

     any two active samplers in the current program object are of
     different types, but refer to the same texture image unit,

     any active sampler in the current program object refers to a texture
     image unit where fixed-function fragment processing accesses a
     texture target that does not match the sampler type, or

     the sum of the number of active samplers in the program and the
     number of texture image units enabled for fixed-function fragment
     processing exceeds the combined limit on the total number of texture
     image units allowed.
   */

   /*
    * Check: any two active samplers in the current program object are of
    * different types, but refer to the same texture image unit,
    */
   if (!_mesa_sampler_uniforms_are_valid(shProg, errMsg, 100))
      return GL_FALSE;

   return GL_TRUE;
}


/**
 * Called via glValidateProgram()
 */
static void
validate_program(struct gl_context *ctx, GLuint program)
{
   struct gl_shader_program *shProg;
   char errMsg[100] = "";

   shProg = _mesa_lookup_shader_program_err(ctx, program, "glValidateProgram");
   if (!shProg) {
      return;
   }

   shProg->Validated = validate_shader_program(shProg, errMsg);
   if (!shProg->Validated) {
      /* update info log */
      if (shProg->InfoLog) {
         ralloc_free(shProg->InfoLog);
      }
      shProg->InfoLog = ralloc_strdup(shProg, errMsg);
   }
}



void GLAPIENTRY
_mesa_AttachObjectARB(GLhandleARB program, GLhandleARB shader)
{
   GET_CURRENT_CONTEXT(ctx);
   attach_shader(ctx, program, shader);
}


void GLAPIENTRY
_mesa_AttachShader(GLuint program, GLuint shader)
{
   GET_CURRENT_CONTEXT(ctx);
   attach_shader(ctx, program, shader);
}


void GLAPIENTRY
_mesa_CompileShader(GLuint shaderObj)
{
   GET_CURRENT_CONTEXT(ctx);
   if (MESA_VERBOSE & VERBOSE_API)
      _mesa_debug(ctx, "glCompileShader %u\n", shaderObj);
   _mesa_compile_shader(ctx, _mesa_lookup_shader_err(ctx, shaderObj,
                                                     "glCompileShader"));
}


GLuint GLAPIENTRY
_mesa_CreateShader(GLenum type)
{
   GET_CURRENT_CONTEXT(ctx);
   if (MESA_VERBOSE & VERBOSE_API)
      _mesa_debug(ctx, "glCreateShader %s\n", _mesa_enum_to_string(type));
   return create_shader(ctx, type);
}


GLhandleARB GLAPIENTRY
_mesa_CreateShaderObjectARB(GLenum type)
{
   GET_CURRENT_CONTEXT(ctx);
   return create_shader(ctx, type);
}


GLuint GLAPIENTRY
_mesa_CreateProgram(void)
{
   GET_CURRENT_CONTEXT(ctx);
   if (MESA_VERBOSE & VERBOSE_API)
      _mesa_debug(ctx, "glCreateProgram\n");
   return create_shader_program(ctx);
}


GLhandleARB GLAPIENTRY
_mesa_CreateProgramObjectARB(void)
{
   GET_CURRENT_CONTEXT(ctx);
   return create_shader_program(ctx);
}


void GLAPIENTRY
_mesa_DeleteObjectARB(GLhandleARB obj)
{
   if (MESA_VERBOSE & VERBOSE_API) {
      GET_CURRENT_CONTEXT(ctx);
      _mesa_debug(ctx, "glDeleteObjectARB(%lu)\n", (unsigned long)obj);
   }

   if (obj) {
      GET_CURRENT_CONTEXT(ctx);
      FLUSH_VERTICES(ctx, 0);
      if (is_program(ctx, obj)) {
         delete_shader_program(ctx, obj);
      }
      else if (is_shader(ctx, obj)) {
         delete_shader(ctx, obj);
      }
      else {
         /* error? */
      }
   }
}


void GLAPIENTRY
_mesa_DeleteProgram(GLuint name)
{
   if (name) {
      GET_CURRENT_CONTEXT(ctx);
      FLUSH_VERTICES(ctx, 0);
      delete_shader_program(ctx, name);
   }
}


void GLAPIENTRY
_mesa_DeleteShader(GLuint name)
{
   if (name) {
      GET_CURRENT_CONTEXT(ctx);
      FLUSH_VERTICES(ctx, 0);
      delete_shader(ctx, name);
   }
}


void GLAPIENTRY
_mesa_DetachObjectARB(GLhandleARB program, GLhandleARB shader)
{
   GET_CURRENT_CONTEXT(ctx);
   detach_shader(ctx, program, shader);
}


void GLAPIENTRY
_mesa_DetachShader(GLuint program, GLuint shader)
{
   GET_CURRENT_CONTEXT(ctx);
   detach_shader(ctx, program, shader);
}


void GLAPIENTRY
_mesa_GetAttachedObjectsARB(GLhandleARB container, GLsizei maxCount,
                            GLsizei * count, GLhandleARB * obj)
{
   GET_CURRENT_CONTEXT(ctx);
   get_attached_shaders(ctx, container, maxCount, count, obj);
}


void GLAPIENTRY
_mesa_GetAttachedShaders(GLuint program, GLsizei maxCount,
                         GLsizei *count, GLuint *obj)
{
   GET_CURRENT_CONTEXT(ctx);
   get_attached_shaders(ctx, program, maxCount, count, obj);
}


void GLAPIENTRY
_mesa_GetInfoLogARB(GLhandleARB object, GLsizei maxLength, GLsizei * length,
                    GLcharARB * infoLog)
{
   GET_CURRENT_CONTEXT(ctx);
   if (is_program(ctx, object)) {
      get_program_info_log(ctx, object, maxLength, length, infoLog);
   }
   else if (is_shader(ctx, object)) {
      get_shader_info_log(ctx, object, maxLength, length, infoLog);
   }
   else {
      _mesa_error(ctx, GL_INVALID_OPERATION, "glGetInfoLogARB");
   }
}


void GLAPIENTRY
_mesa_GetObjectParameterivARB(GLhandleARB object, GLenum pname, GLint *params)
{
   GET_CURRENT_CONTEXT(ctx);
   /* Implement in terms of GetProgramiv, GetShaderiv */
   if (is_program(ctx, object)) {
      if (pname == GL_OBJECT_TYPE_ARB) {
	 *params = GL_PROGRAM_OBJECT_ARB;
      }
      else {
	 get_programiv(ctx, object, pname, params);
      }
   }
   else if (is_shader(ctx, object)) {
      if (pname == GL_OBJECT_TYPE_ARB) {
	 *params = GL_SHADER_OBJECT_ARB;
      }
      else {
	 get_shaderiv(ctx, object, pname, params);
      }
   }
   else {
      _mesa_error(ctx, GL_INVALID_VALUE, "glGetObjectParameterivARB");
   }
}


void GLAPIENTRY
_mesa_GetObjectParameterfvARB(GLhandleARB object, GLenum pname,
                              GLfloat *params)
{
   GLint iparams[1] = {0};  /* XXX is one element enough? */
   _mesa_GetObjectParameterivARB(object, pname, iparams);
   params[0] = (GLfloat) iparams[0];
}


void GLAPIENTRY
_mesa_GetProgramiv(GLuint program, GLenum pname, GLint *params)
{
   GET_CURRENT_CONTEXT(ctx);
   get_programiv(ctx, program, pname, params);
}


void GLAPIENTRY
_mesa_GetShaderiv(GLuint shader, GLenum pname, GLint *params)
{
   GET_CURRENT_CONTEXT(ctx);
   get_shaderiv(ctx, shader, pname, params);
}


void GLAPIENTRY
_mesa_GetProgramInfoLog(GLuint program, GLsizei bufSize,
                        GLsizei *length, GLchar *infoLog)
{
   GET_CURRENT_CONTEXT(ctx);
   get_program_info_log(ctx, program, bufSize, length, infoLog);
}


void GLAPIENTRY
_mesa_GetShaderInfoLog(GLuint shader, GLsizei bufSize,
                       GLsizei *length, GLchar *infoLog)
{
   GET_CURRENT_CONTEXT(ctx);
   get_shader_info_log(ctx, shader, bufSize, length, infoLog);
}


void GLAPIENTRY
_mesa_GetShaderSource(GLuint shader, GLsizei maxLength,
                      GLsizei *length, GLchar *sourceOut)
{
   GET_CURRENT_CONTEXT(ctx);
   get_shader_source(ctx, shader, maxLength, length, sourceOut);
}


GLhandleARB GLAPIENTRY
_mesa_GetHandleARB(GLenum pname)
{
   GET_CURRENT_CONTEXT(ctx);
   return get_handle(ctx, pname);
}


GLboolean GLAPIENTRY
_mesa_IsProgram(GLuint name)
{
   GET_CURRENT_CONTEXT(ctx);
   return is_program(ctx, name);
}


GLboolean GLAPIENTRY
_mesa_IsShader(GLuint name)
{
   GET_CURRENT_CONTEXT(ctx);
   return is_shader(ctx, name);
}


void GLAPIENTRY
_mesa_LinkProgram(GLuint programObj)
{
   GET_CURRENT_CONTEXT(ctx);
   if (MESA_VERBOSE & VERBOSE_API)
      _mesa_debug(ctx, "glLinkProgram %u\n", programObj);
   _mesa_link_program(ctx, _mesa_lookup_shader_program_err(ctx, programObj,
                                                           "glLinkProgram"));
}

#if defined(HAVE_SHA1)
/**
 * Generate a SHA-1 hash value string for given source string.
 */
static void
generate_sha1(const char *source, char sha_str[64])
{
   unsigned char sha[20];
   _mesa_sha1_compute(source, strlen(source), sha);
   _mesa_sha1_format(sha_str, sha);
}

/**
 * Construct a full path for shader replacement functionality using
 * following format:
 *
 * <path>/<stage prefix>_<CHECKSUM>.glsl
 */
static void
construct_name(const gl_shader_stage stage, const char *source,
               const char *path, char *name, unsigned length)
{
   char sha[64];
   static const char *types[] = {
      "VS", "TC", "TE", "GS", "FS", "CS",
   };

   generate_sha1(source, sha);
   _mesa_snprintf(name, length, "%s/%s_%s.glsl", path, types[stage],
                  sha);
}

/**
 * Write given shader source to a file in MESA_SHADER_DUMP_PATH.
 */
static void
dump_shader(const gl_shader_stage stage, const char *source)
{
   char name[PATH_MAX];
   static bool path_exists = true;
   char *dump_path;
   FILE *f;

   if (!path_exists)
      return;

   dump_path = getenv("MESA_SHADER_DUMP_PATH");
   if (!dump_path) {
      path_exists = false;
      return;
   }

   construct_name(stage, source, dump_path, name, PATH_MAX);

   f = fopen(name, "w");
   if (f) {
      fputs(source, f);
      fclose(f);
   } else {
      GET_CURRENT_CONTEXT(ctx);
      _mesa_warning(ctx, "could not open %s for dumping shader (%s)", name,
                    strerror(errno));
   }
}

/**
 * Read shader source code from a file.
 * Useful for debugging to override an app's shader.
 */
static GLcharARB *
read_shader(const gl_shader_stage stage, const char *source)
{
   char name[PATH_MAX];
   char *read_path;
   static bool path_exists = true;
   int len, shader_size = 0;
   GLcharARB *buffer;
   FILE *f;

   if (!path_exists)
      return NULL;

   read_path = getenv("MESA_SHADER_READ_PATH");
   if (!read_path) {
      path_exists = false;
      return NULL;
   }

   construct_name(stage, source, read_path, name, PATH_MAX);

   f = fopen(name, "r");
   if (!f)
      return NULL;

   /* allocate enough room for the entire shader */
   fseek(f, 0, SEEK_END);
   shader_size = ftell(f);
   rewind(f);
   assert(shader_size);

   /* add one for terminating zero */
   shader_size++;

   buffer = malloc(shader_size);
   assert(buffer);

   len = fread(buffer, 1, shader_size, f);
   buffer[len] = 0;

   fclose(f);

   return buffer;
}
#endif /* HAVE_SHA1 */

/**
 * Called via glShaderSource() and glShaderSourceARB() API functions.
 * Basically, concatenate the source code strings into one long string
 * and pass it to _mesa_shader_source().
 */
void GLAPIENTRY
_mesa_ShaderSource(GLuint shaderObj, GLsizei count,
                   const GLchar * const * string, const GLint * length)
{
   GET_CURRENT_CONTEXT(ctx);
   GLint *offsets;
   GLsizei i, totalLength;
   GLcharARB *source;
   struct gl_shader *sh;

#if defined(HAVE_SHA1)
   GLcharARB *replacement;
#endif /* HAVE_SHA1 */

   sh = _mesa_lookup_shader_err(ctx, shaderObj, "glShaderSourceARB");
   if (!sh)
      return;

   if (string == NULL) {
      _mesa_error(ctx, GL_INVALID_VALUE, "glShaderSourceARB");
      return;
   }

   /*
    * This array holds offsets of where the appropriate string ends, thus the
    * last element will be set to the total length of the source code.
    */
   offsets = malloc(count * sizeof(GLint));
   if (offsets == NULL) {
      _mesa_error(ctx, GL_OUT_OF_MEMORY, "glShaderSourceARB");
      return;
   }

   for (i = 0; i < count; i++) {
      if (string[i] == NULL) {
         free((GLvoid *) offsets);
         _mesa_error(ctx, GL_INVALID_OPERATION,
                     "glShaderSourceARB(null string)");
         return;
      }
      if (length == NULL || length[i] < 0)
         offsets[i] = strlen(string[i]);
      else
         offsets[i] = length[i];
      /* accumulate string lengths */
      if (i > 0)
         offsets[i] += offsets[i - 1];
   }

   /* Total length of source string is sum off all strings plus two.
    * One extra byte for terminating zero, another extra byte to silence
    * valgrind warnings in the parser/grammer code.
    */
   totalLength = offsets[count - 1] + 2;
   source = malloc(totalLength * sizeof(GLcharARB));
   if (source == NULL) {
      free((GLvoid *) offsets);
      _mesa_error(ctx, GL_OUT_OF_MEMORY, "glShaderSourceARB");
      return;
   }

   for (i = 0; i < count; i++) {
      GLint start = (i > 0) ? offsets[i - 1] : 0;
      memcpy(source + start, string[i],
             (offsets[i] - start) * sizeof(GLcharARB));
   }
   source[totalLength - 1] = '\0';
   source[totalLength - 2] = '\0';

#if defined(HAVE_SHA1)
   /* Dump original shader source to MESA_SHADER_DUMP_PATH and replace
    * if corresponding entry found from MESA_SHADER_READ_PATH.
    */
   dump_shader(sh->Stage, source);

   replacement = read_shader(sh->Stage, source);
   if (replacement) {
      free(source);
      source = replacement;
   }
#endif /* HAVE_SHA1 */

   shader_source(sh, source);

   free(offsets);
}


void GLAPIENTRY
_mesa_UseProgram(GLuint program)
{
   GET_CURRENT_CONTEXT(ctx);
   struct gl_shader_program *shProg;

   if (MESA_VERBOSE & VERBOSE_API)
      _mesa_debug(ctx, "glUseProgram %u\n", program);

   if (_mesa_is_xfb_active_and_unpaused(ctx)) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "glUseProgram(transform feedback active)");
      return;
   }

   if (program) {
      shProg = _mesa_lookup_shader_program_err(ctx, program, "glUseProgram");
      if (!shProg) {
         return;
      }
      if (!shProg->LinkStatus) {
         _mesa_error(ctx, GL_INVALID_OPERATION,
                     "glUseProgram(program %u not linked)", program);
         return;
      }

      /* debug code */
      if (ctx->_Shader->Flags & GLSL_USE_PROG) {
         print_shader_info(shProg);
      }
   }
   else {
      shProg = NULL;
   }

   /* The ARB_separate_shader_object spec says:
    *
    *     "The executable code for an individual shader stage is taken from
    *     the current program for that stage.  If there is a current program
    *     object established by UseProgram, that program is considered current
    *     for all stages.  Otherwise, if there is a bound program pipeline
    *     object (section 2.14.PPO), the program bound to the appropriate
    *     stage of the pipeline object is considered current."
    */
   if (program) {
      /* Attach shader state to the binding point */
      _mesa_reference_pipeline_object(ctx, &ctx->_Shader, &ctx->Shader);
      /* Update the program */
      _mesa_use_program(ctx, shProg);
   } else {
      /* Must be done first: detach the progam */
      _mesa_use_program(ctx, shProg);
      /* Unattach shader_state binding point */
      _mesa_reference_pipeline_object(ctx, &ctx->_Shader, ctx->Pipeline.Default);
      /* If a pipeline was bound, rebind it */
      if (ctx->Pipeline.Current) {
         _mesa_BindProgramPipeline(ctx->Pipeline.Current->Name);
      }
   }
}


void GLAPIENTRY
_mesa_ValidateProgram(GLuint program)
{
   GET_CURRENT_CONTEXT(ctx);
   validate_program(ctx, program);
}


/**
 * For OpenGL ES 2.0, GL_ARB_ES2_compatibility
 */
void GLAPIENTRY
_mesa_GetShaderPrecisionFormat(GLenum shadertype, GLenum precisiontype,
                               GLint* range, GLint* precision)
{
   const struct gl_program_constants *limits;
   const struct gl_precision *p;
   GET_CURRENT_CONTEXT(ctx);

   switch (shadertype) {
   case GL_VERTEX_SHADER:
      limits = &ctx->Const.Program[MESA_SHADER_VERTEX];
      break;
   case GL_FRAGMENT_SHADER:
      limits = &ctx->Const.Program[MESA_SHADER_FRAGMENT];
      break;
   default:
      _mesa_error(ctx, GL_INVALID_ENUM,
                  "glGetShaderPrecisionFormat(shadertype)");
      return;
   }

   switch (precisiontype) {
   case GL_LOW_FLOAT:
      p = &limits->LowFloat;
      break;
   case GL_MEDIUM_FLOAT:
      p = &limits->MediumFloat;
      break;
   case GL_HIGH_FLOAT:
      p = &limits->HighFloat;
      break;
   case GL_LOW_INT:
      p = &limits->LowInt;
      break;
   case GL_MEDIUM_INT:
      p = &limits->MediumInt;
      break;
   case GL_HIGH_INT:
      p = &limits->HighInt;
      break;
   default:
      _mesa_error(ctx, GL_INVALID_ENUM,
                  "glGetShaderPrecisionFormat(precisiontype)");
      return;
   }

   range[0] = p->RangeMin;
   range[1] = p->RangeMax;
   precision[0] = p->Precision;
}


/**
 * For OpenGL ES 2.0, GL_ARB_ES2_compatibility
 */
void GLAPIENTRY
_mesa_ReleaseShaderCompiler(void)
{
   _mesa_destroy_shader_compiler_caches();
}


/**
 * For OpenGL ES 2.0, GL_ARB_ES2_compatibility
 */
void GLAPIENTRY
_mesa_ShaderBinary(GLint n, const GLuint* shaders, GLenum binaryformat,
                   const void* binary, GLint length)
{
   GET_CURRENT_CONTEXT(ctx);
   (void) shaders;
   (void) binaryformat;
   (void) binary;

   /* Page 68, section 7.2 'Shader Binaries" of the of the OpenGL ES 3.1, and
    * page 88 of the OpenGL 4.5 specs state:
    *
    *     "An INVALID_VALUE error is generated if count or length is negative.
    *      An INVALID_ENUM error is generated if binaryformat is not a supported
    *      format returned in SHADER_BINARY_FORMATS."
    */
   if (n < 0 || length < 0) {
      _mesa_error(ctx, GL_INVALID_VALUE, "glShaderBinary(count or length < 0)");
      return;
   }

   _mesa_error(ctx, GL_INVALID_ENUM, "glShaderBinary(format)");
}


void GLAPIENTRY
_mesa_GetProgramBinary(GLuint program, GLsizei bufSize, GLsizei *length,
                       GLenum *binaryFormat, GLvoid *binary)
{
   struct gl_shader_program *shProg;
   GLsizei length_dummy;
   GET_CURRENT_CONTEXT(ctx);

   if (bufSize < 0){
      _mesa_error(ctx, GL_INVALID_VALUE, "glGetProgramBinary(bufSize < 0)");
      return;
   }

   shProg = _mesa_lookup_shader_program_err(ctx, program, "glGetProgramBinary");
   if (!shProg)
      return;

   /* The ARB_get_program_binary spec says:
    *
    *     "If <length> is NULL, then no length is returned."
    *
    * Ensure that length always points to valid storage to avoid multiple NULL
    * pointer checks below.
    */
   if (length == NULL)
      length = &length_dummy;


   /* The ARB_get_program_binary spec says:
    *
    *     "When a program object's LINK_STATUS is FALSE, its program binary
    *     length is zero, and a call to GetProgramBinary will generate an
    *     INVALID_OPERATION error.
    */
   if (!shProg->LinkStatus) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "glGetProgramBinary(program %u not linked)",
                  shProg->Name);
      *length = 0;
      return;
   }

   *length = 0;
   _mesa_error(ctx, GL_INVALID_OPERATION,
               "glGetProgramBinary(driver supports zero binary formats)");

   (void) binaryFormat;
   (void) binary;
}

void GLAPIENTRY
_mesa_ProgramBinary(GLuint program, GLenum binaryFormat,
                    const GLvoid *binary, GLsizei length)
{
   struct gl_shader_program *shProg;
   GET_CURRENT_CONTEXT(ctx);

   shProg = _mesa_lookup_shader_program_err(ctx, program, "glProgramBinary");
   if (!shProg)
      return;

   (void) binaryFormat;
   (void) binary;

   /* Section 2.3.1 (Errors) of the OpenGL 4.5 spec says:
    *
    *     "If a negative number is provided where an argument of type sizei or
    *     sizeiptr is specified, an INVALID_VALUE error is generated."
    */
   if (length < 0) {
      _mesa_error(ctx, GL_INVALID_VALUE, "glProgramBinary(length < 0)");
      return;
   }

   /* The ARB_get_program_binary spec says:
    *
    *     "<binaryFormat> and <binary> must be those returned by a previous
    *     call to GetProgramBinary, and <length> must be the length of the
    *     program binary as returned by GetProgramBinary or GetProgramiv with
    *     <pname> PROGRAM_BINARY_LENGTH. Loading the program binary will fail,
    *     setting the LINK_STATUS of <program> to FALSE, if these conditions
    *     are not met."
    *
    * Since any value of binaryFormat passed "is not one of those specified as
    * allowable for [this] command, an INVALID_ENUM error is generated."
    */
   shProg->LinkStatus = GL_FALSE;
   _mesa_error(ctx, GL_INVALID_ENUM, "glProgramBinary");
}


void GLAPIENTRY
_mesa_ProgramParameteri(GLuint program, GLenum pname, GLint value)
{
   struct gl_shader_program *shProg;
   GET_CURRENT_CONTEXT(ctx);

   shProg = _mesa_lookup_shader_program_err(ctx, program,
                                            "glProgramParameteri");
   if (!shProg)
      return;

   switch (pname) {
   case GL_PROGRAM_BINARY_RETRIEVABLE_HINT:
      /* This enum isn't part of the OES extension for OpenGL ES 2.0, but it
       * is part of OpenGL ES 3.0.  For the ES2 case, this function shouldn't
       * even be in the dispatch table, so we shouldn't need to expclicitly
       * check here.
       *
       * On desktop, we ignore the 3.0+ requirement because it is silly.
       */

      /* The ARB_get_program_binary extension spec says:
       *
       *     "An INVALID_VALUE error is generated if the <value> argument to
       *     ProgramParameteri is not TRUE or FALSE."
       */
      if (value != GL_TRUE && value != GL_FALSE) {
         goto invalid_value;
      }

      /* No need to notify the driver.  Any changes will actually take effect
       * the next time the shader is linked.
       *
       * The ARB_get_program_binary extension spec says:
       *
       *     "To indicate that a program binary is likely to be retrieved,
       *     ProgramParameteri should be called with <pname>
       *     PROGRAM_BINARY_RETRIEVABLE_HINT and <value> TRUE. This setting
       *     will not be in effect until the next time LinkProgram or
       *     ProgramBinary has been called successfully."
       *
       * The resloution of issue 9 in the extension spec also says:
       *
       *     "The application may use the PROGRAM_BINARY_RETRIEVABLE_HINT hint
       *     to indicate to the GL implementation that this program will
       *     likely be saved with GetProgramBinary at some point. This will
       *     give the GL implementation the opportunity to track any state
       *     changes made to the program before being saved such that when it
       *     is loaded again a recompile can be avoided."
       */
      shProg->BinaryRetreivableHint = value;
      return;

   case GL_PROGRAM_SEPARABLE:
      /* Spec imply that the behavior is the same as ARB_get_program_binary
       * Chapter 7.3 Program Objects
       */
      if (value != GL_TRUE && value != GL_FALSE) {
         goto invalid_value;
      }
      shProg->SeparateShader = value;
      return;

   default:
      _mesa_error(ctx, GL_INVALID_ENUM, "glProgramParameteri(pname=%s)",
                  _mesa_enum_to_string(pname));
      return;
   }

invalid_value:
   _mesa_error(ctx, GL_INVALID_VALUE,
               "glProgramParameteri(pname=%s, value=%d): "
               "value must be 0 or 1.",
               _mesa_enum_to_string(pname),
               value);
}


void
_mesa_use_shader_program(struct gl_context *ctx, GLenum type,
                         struct gl_shader_program *shProg,
                         struct gl_pipeline_object *shTarget)
{
   gl_shader_stage stage = _mesa_shader_enum_to_shader_stage(type);
   use_shader_program(ctx, stage, shProg, shTarget);

   if (ctx->Driver.UseProgram)
      ctx->Driver.UseProgram(ctx, shProg);
}


/**
 * Copy program-specific data generated by linking from the gl_shader_program
 * object to a specific gl_program object.
 */
void
_mesa_copy_linked_program_data(gl_shader_stage type,
                               const struct gl_shader_program *src,
                               struct gl_program *dst)
{
   switch (type) {
   case MESA_SHADER_VERTEX:
      dst->ClipDistanceArraySize = src->Vert.ClipDistanceArraySize;
      dst->CullDistanceArraySize = src->Vert.CullDistanceArraySize;
      break;
   case MESA_SHADER_TESS_CTRL: {
      struct gl_tess_ctrl_program *dst_tcp =
         (struct gl_tess_ctrl_program *) dst;
      dst_tcp->VerticesOut = src->TessCtrl.VerticesOut;
      break;
   }
   case MESA_SHADER_TESS_EVAL: {
      struct gl_tess_eval_program *dst_tep =
         (struct gl_tess_eval_program *) dst;
      dst_tep->PrimitiveMode = src->TessEval.PrimitiveMode;
      dst_tep->Spacing = src->TessEval.Spacing;
      dst_tep->VertexOrder = src->TessEval.VertexOrder;
      dst_tep->PointMode = src->TessEval.PointMode;
      dst->ClipDistanceArraySize = src->TessEval.ClipDistanceArraySize;
      dst->CullDistanceArraySize = src->TessEval.CullDistanceArraySize;
      break;
   }
   case MESA_SHADER_GEOMETRY: {
      struct gl_geometry_program *dst_gp = (struct gl_geometry_program *) dst;
      dst_gp->VerticesIn = src->Geom.VerticesIn;
      dst_gp->VerticesOut = src->Geom.VerticesOut;
      dst_gp->Invocations = src->Geom.Invocations;
      dst_gp->InputType = src->Geom.InputType;
      dst_gp->OutputType = src->Geom.OutputType;
      dst->ClipDistanceArraySize = src->Geom.ClipDistanceArraySize;
      dst->CullDistanceArraySize = src->Geom.CullDistanceArraySize;
      dst_gp->UsesEndPrimitive = src->Geom.UsesEndPrimitive;
      dst_gp->UsesStreams = src->Geom.UsesStreams;
      break;
   }
   case MESA_SHADER_FRAGMENT: {
      struct gl_fragment_program *dst_fp = (struct gl_fragment_program *) dst;
      dst_fp->FragDepthLayout = src->FragDepthLayout;
      break;
   }
   case MESA_SHADER_COMPUTE: {
      struct gl_compute_program *dst_cp = (struct gl_compute_program *) dst;
      int i;
      for (i = 0; i < 3; i++)
         dst_cp->LocalSize[i] = src->Comp.LocalSize[i];
      dst_cp->SharedSize = src->Comp.SharedSize;
      break;
   }
   default:
      break;
   }
}

/**
 * ARB_separate_shader_objects: Compile & Link Program
 */
GLuint GLAPIENTRY
_mesa_CreateShaderProgramv(GLenum type, GLsizei count,
                           const GLchar* const *strings)
{
   GET_CURRENT_CONTEXT(ctx);

   const GLuint shader = create_shader(ctx, type);
   GLuint program = 0;

   /*
    * According to OpenGL 4.5 and OpenGL ES 3.1 standards, section 7.3:
    * GL_INVALID_VALUE should be generated if count < 0
    */
   if (count < 0) {
      _mesa_error(ctx, GL_INVALID_VALUE, "glCreateShaderProgram (count < 0)");
      return program;
   }

   if (shader) {
      struct gl_shader *sh = _mesa_lookup_shader(ctx, shader);

      _mesa_ShaderSource(shader, count, strings, NULL);
      _mesa_compile_shader(ctx, sh);

      program = create_shader_program(ctx);
      if (program) {
	 struct gl_shader_program *shProg;
	 GLint compiled = GL_FALSE;

	 shProg = _mesa_lookup_shader_program(ctx, program);

	 shProg->SeparateShader = GL_TRUE;

	 get_shaderiv(ctx, shader, GL_COMPILE_STATUS, &compiled);
	 if (compiled) {
	    attach_shader(ctx, program, shader);
	    _mesa_link_program(ctx, shProg);
	    detach_shader(ctx, program, shader);

#if 0
	    /* Possibly... */
	    if (active-user-defined-varyings-in-linked-program) {
	       append-error-to-info-log;
	       shProg->LinkStatus = GL_FALSE;
	    }
#endif
	 }
         if (sh->InfoLog)
            ralloc_strcat(&shProg->InfoLog, sh->InfoLog);
      }

      delete_shader(ctx, shader);
   }

   return program;
}


/**
 * For GL_ARB_tessellation_shader
 */
extern void GLAPIENTRY
_mesa_PatchParameteri(GLenum pname, GLint value)
{
   GET_CURRENT_CONTEXT(ctx);

   if (!_mesa_has_tessellation(ctx)) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "glPatchParameteri");
      return;
   }

   if (pname != GL_PATCH_VERTICES) {
      _mesa_error(ctx, GL_INVALID_ENUM, "glPatchParameteri");
      return;
   }

   if (value <= 0 || value > ctx->Const.MaxPatchVertices) {
      _mesa_error(ctx, GL_INVALID_VALUE, "glPatchParameteri");
      return;
   }

   ctx->TessCtrlProgram.patch_vertices = value;
}


extern void GLAPIENTRY
_mesa_PatchParameterfv(GLenum pname, const GLfloat *values)
{
   GET_CURRENT_CONTEXT(ctx);

   if (!_mesa_has_tessellation(ctx)) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "glPatchParameterfv");
      return;
   }

   switch(pname) {
   case GL_PATCH_DEFAULT_OUTER_LEVEL:
      FLUSH_VERTICES(ctx, 0);
      memcpy(ctx->TessCtrlProgram.patch_default_outer_level, values,
             4 * sizeof(GLfloat));
      ctx->NewDriverState |= ctx->DriverFlags.NewDefaultTessLevels;
      return;
   case GL_PATCH_DEFAULT_INNER_LEVEL:
      FLUSH_VERTICES(ctx, 0);
      memcpy(ctx->TessCtrlProgram.patch_default_inner_level, values,
             2 * sizeof(GLfloat));
      ctx->NewDriverState |= ctx->DriverFlags.NewDefaultTessLevels;
      return;
   default:
      _mesa_error(ctx, GL_INVALID_ENUM, "glPatchParameterfv");
      return;
   }
}

/**
 * ARB_shader_subroutine
 */
GLint GLAPIENTRY
_mesa_GetSubroutineUniformLocation(GLuint program, GLenum shadertype,
                                   const GLchar *name)
{
   GET_CURRENT_CONTEXT(ctx);
   const char *api_name = "glGetSubroutineUniformLocation";
   struct gl_shader_program *shProg;
   GLenum resource_type;
   gl_shader_stage stage;

   if (!_mesa_has_shader_subroutine(ctx)) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return -1;
   }

   if (!_mesa_validate_shader_target(ctx, shadertype)) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return -1;
   }

   shProg = _mesa_lookup_shader_program_err(ctx, program, api_name);
   if (!shProg)
      return -1;

   stage = _mesa_shader_enum_to_shader_stage(shadertype);
   if (!shProg->_LinkedShaders[stage]) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return -1;
   }

   resource_type = _mesa_shader_stage_to_subroutine_uniform(stage);
   return _mesa_program_resource_location(shProg, resource_type, name);
}

GLuint GLAPIENTRY
_mesa_GetSubroutineIndex(GLuint program, GLenum shadertype,
                         const GLchar *name)
{
   GET_CURRENT_CONTEXT(ctx);
   const char *api_name = "glGetSubroutineIndex";
   struct gl_shader_program *shProg;
   struct gl_program_resource *res;
   GLenum resource_type;
   gl_shader_stage stage;

   if (!_mesa_has_shader_subroutine(ctx)) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return -1;
   }

   if (!_mesa_validate_shader_target(ctx, shadertype)) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return -1;
   }

   shProg = _mesa_lookup_shader_program_err(ctx, program, api_name);
   if (!shProg)
      return -1;

   stage = _mesa_shader_enum_to_shader_stage(shadertype);
   if (!shProg->_LinkedShaders[stage]) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return -1;
   }

   resource_type = _mesa_shader_stage_to_subroutine(stage);
   res = _mesa_program_resource_find_name(shProg, resource_type, name, NULL);
   if (!res) {
     return -1;
   }

   return _mesa_program_resource_index(shProg, res);
}


GLvoid GLAPIENTRY
_mesa_GetActiveSubroutineUniformiv(GLuint program, GLenum shadertype,
                                   GLuint index, GLenum pname, GLint *values)
{
   GET_CURRENT_CONTEXT(ctx);
   const char *api_name = "glGetActiveSubroutineUniformiv";
   struct gl_shader_program *shProg;
   struct gl_shader *sh;
   gl_shader_stage stage;
   struct gl_program_resource *res;
   const struct gl_uniform_storage *uni;
   GLenum resource_type;
   int count, i, j;

   if (!_mesa_has_shader_subroutine(ctx)) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }

   if (!_mesa_validate_shader_target(ctx, shadertype)) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }

   shProg = _mesa_lookup_shader_program_err(ctx, program, api_name);
   if (!shProg)
      return;

   stage = _mesa_shader_enum_to_shader_stage(shadertype);
   resource_type = _mesa_shader_stage_to_subroutine_uniform(stage);

   sh = shProg->_LinkedShaders[stage];
   if (!sh) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }

   if (index >= sh->NumSubroutineUniforms) {
      _mesa_error(ctx, GL_INVALID_VALUE, "%s: invalid index greater than GL_ACTIVE_SUBROUTINE_UNIFORMS", api_name);
      return;
   }

   switch (pname) {
   case GL_NUM_COMPATIBLE_SUBROUTINES: {
      res = _mesa_program_resource_find_index(shProg, resource_type, index);
      if (res) {
         uni = res->Data;
         values[0] = uni->num_compatible_subroutines;
      }
      break;
   }
   case GL_COMPATIBLE_SUBROUTINES: {
      res = _mesa_program_resource_find_index(shProg, resource_type, index);
      if (res) {
         uni = res->Data;
         count = 0;
         for (i = 0; i < sh->NumSubroutineFunctions; i++) {
            struct gl_subroutine_function *fn = &sh->SubroutineFunctions[i];
            for (j = 0; j < fn->num_compat_types; j++) {
               if (fn->types[j] == uni->type) {
                  values[count++] = i;
                  break;
               }
            }
         }
      }
      break;
   }
   case GL_UNIFORM_SIZE:
      res = _mesa_program_resource_find_index(shProg, resource_type, index);
      if (res) {
         uni = res->Data;
         values[0] = uni->array_elements ? uni->array_elements : 1;
      }
      break;
   case GL_UNIFORM_NAME_LENGTH:
      res = _mesa_program_resource_find_index(shProg, resource_type, index);
      if (res) {
         values[0] = strlen(_mesa_program_resource_name(res)) + 1
            + ((_mesa_program_resource_array_size(res) != 0) ? 3 : 0);
      }
      break;
   default:
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }
}


GLvoid GLAPIENTRY
_mesa_GetActiveSubroutineUniformName(GLuint program, GLenum shadertype,
                                     GLuint index, GLsizei bufsize,
                                     GLsizei *length, GLchar *name)
{
   GET_CURRENT_CONTEXT(ctx);
   const char *api_name = "glGetActiveSubroutineUniformName";
   struct gl_shader_program *shProg;
   GLenum resource_type;
   gl_shader_stage stage;

   if (!_mesa_has_shader_subroutine(ctx)) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }

   if (!_mesa_validate_shader_target(ctx, shadertype)) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }

   shProg = _mesa_lookup_shader_program_err(ctx, program, api_name);
   if (!shProg)
      return;

   stage = _mesa_shader_enum_to_shader_stage(shadertype);
   if (!shProg->_LinkedShaders[stage]) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }

   resource_type = _mesa_shader_stage_to_subroutine_uniform(stage);
   /* get program resource name */
   _mesa_get_program_resource_name(shProg, resource_type,
                                   index, bufsize,
                                   length, name, api_name);
}


GLvoid GLAPIENTRY
_mesa_GetActiveSubroutineName(GLuint program, GLenum shadertype,
                              GLuint index, GLsizei bufsize,
                              GLsizei *length, GLchar *name)
{
   GET_CURRENT_CONTEXT(ctx);
   const char *api_name = "glGetActiveSubroutineName";
   struct gl_shader_program *shProg;
   GLenum resource_type;
   gl_shader_stage stage;

   if (!_mesa_has_shader_subroutine(ctx)) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }

   if (!_mesa_validate_shader_target(ctx, shadertype)) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }

   shProg = _mesa_lookup_shader_program_err(ctx, program, api_name);
   if (!shProg)
      return;

   stage = _mesa_shader_enum_to_shader_stage(shadertype);
   if (!shProg->_LinkedShaders[stage]) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }
   resource_type = _mesa_shader_stage_to_subroutine(stage);
   _mesa_get_program_resource_name(shProg, resource_type,
                                   index, bufsize,
                                   length, name, api_name);
}


GLvoid GLAPIENTRY
_mesa_UniformSubroutinesuiv(GLenum shadertype, GLsizei count,
                            const GLuint *indices)
{
   GET_CURRENT_CONTEXT(ctx);
   const char *api_name = "glUniformSubroutinesuiv";
   struct gl_shader_program *shProg;
   struct gl_shader *sh;
   gl_shader_stage stage;
   int i;

   if (!_mesa_has_shader_subroutine(ctx)) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }

   if (!_mesa_validate_shader_target(ctx, shadertype)) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }

   stage = _mesa_shader_enum_to_shader_stage(shadertype);
   shProg = ctx->_Shader->CurrentProgram[stage];
   if (!shProg) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }

   sh = shProg->_LinkedShaders[stage];
   if (!sh) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }

   if (count != sh->NumSubroutineUniformRemapTable) {
      _mesa_error(ctx, GL_INVALID_VALUE, "%s", api_name);
      return;
   }

   i = 0;
   do {
      struct gl_uniform_storage *uni = sh->SubroutineUniformRemapTable[i];
      if (uni == NULL) {
         i++;
         continue;
      }

      int uni_count = uni->array_elements ? uni->array_elements : 1;
      int j, k;

      for (j = i; j < i + uni_count; j++) {
         struct gl_subroutine_function *subfn;
         if (indices[j] >= sh->NumSubroutineFunctions) {
            _mesa_error(ctx, GL_INVALID_VALUE, "%s", api_name);
            return;
         }

         subfn = &sh->SubroutineFunctions[indices[j]];
         for (k = 0; k < subfn->num_compat_types; k++) {
            if (subfn->types[k] == uni->type)
               break;
         }
         if (k == subfn->num_compat_types) {
            _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
            return;
         }
      }
      i += uni_count;
   } while(i < count);

   FLUSH_VERTICES(ctx, _NEW_PROGRAM_CONSTANTS);
   i = 0;
   do {
      struct gl_uniform_storage *uni = sh->SubroutineUniformRemapTable[i];
      if (uni == NULL) {
         i++;
         continue;
      }

      int uni_count = uni->array_elements ? uni->array_elements : 1;

      memcpy(&uni->storage[0], &indices[i],
             sizeof(GLuint) * uni_count);

      _mesa_propagate_uniforms_to_driver_storage(uni, 0, uni_count);
      i += uni_count;
   } while(i < count);
}


GLvoid GLAPIENTRY
_mesa_GetUniformSubroutineuiv(GLenum shadertype, GLint location,
                              GLuint *params)
{
   GET_CURRENT_CONTEXT(ctx);
   const char *api_name = "glGetUniformSubroutineuiv";
   struct gl_shader_program *shProg;
   struct gl_shader *sh;
   gl_shader_stage stage;

   if (!_mesa_has_shader_subroutine(ctx)) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }

   if (!_mesa_validate_shader_target(ctx, shadertype)) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }

   stage = _mesa_shader_enum_to_shader_stage(shadertype);
   shProg = ctx->_Shader->CurrentProgram[stage];
   if (!shProg) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }

   sh = shProg->_LinkedShaders[stage];
   if (!sh) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }

   if (location >= sh->NumSubroutineUniformRemapTable) {
      _mesa_error(ctx, GL_INVALID_VALUE, "%s", api_name);
      return;
   }

   {
      struct gl_uniform_storage *uni = sh->SubroutineUniformRemapTable[location];
      int offset = location - uni->opaque[stage].index;
      memcpy(params, &uni->storage[offset],
	     sizeof(GLuint));
   }
}


GLvoid GLAPIENTRY
_mesa_GetProgramStageiv(GLuint program, GLenum shadertype,
                        GLenum pname, GLint *values)
{
   GET_CURRENT_CONTEXT(ctx);
   const char *api_name = "glGetProgramStageiv";
   struct gl_shader_program *shProg;
   struct gl_shader *sh;
   gl_shader_stage stage;

   if (!_mesa_has_shader_subroutine(ctx)) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }

   if (!_mesa_validate_shader_target(ctx, shadertype)) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }

   shProg = _mesa_lookup_shader_program_err(ctx, program, api_name);
   if (!shProg)
      return;

   stage = _mesa_shader_enum_to_shader_stage(shadertype);
   sh = shProg->_LinkedShaders[stage];
   if (!sh) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }

   switch (pname) {
   case GL_ACTIVE_SUBROUTINES:
      values[0] = sh->NumSubroutineFunctions;
      break;
   case GL_ACTIVE_SUBROUTINE_UNIFORM_LOCATIONS:
      values[0] = sh->NumSubroutineUniformRemapTable;
      break;
   case GL_ACTIVE_SUBROUTINE_UNIFORMS:
      values[0] = sh->NumSubroutineUniforms;
      break;
   case GL_ACTIVE_SUBROUTINE_MAX_LENGTH:
   {
      unsigned i;
      GLint max_len = 0;
      GLenum resource_type;
      struct gl_program_resource *res;

      resource_type = _mesa_shader_stage_to_subroutine(stage);
      for (i = 0; i < sh->NumSubroutineFunctions; i++) {
         res = _mesa_program_resource_find_index(shProg, resource_type, i);
         if (res) {
            const GLint len = strlen(_mesa_program_resource_name(res)) + 1;
            if (len > max_len)
               max_len = len;
         }
      }
      values[0] = max_len;
      break;
   }
   case GL_ACTIVE_SUBROUTINE_UNIFORM_MAX_LENGTH:
   {
      unsigned i;
      GLint max_len = 0;
      GLenum resource_type;
      struct gl_program_resource *res;

      resource_type = _mesa_shader_stage_to_subroutine_uniform(stage);
      for (i = 0; i < sh->NumSubroutineUniformRemapTable; i++) {
         res = _mesa_program_resource_find_index(shProg, resource_type, i);
         if (res) {
            const GLint len = strlen(_mesa_program_resource_name(res)) + 1
               + ((_mesa_program_resource_array_size(res) != 0) ? 3 : 0);

            if (len > max_len)
               max_len = len;
         }
      }
      values[0] = max_len;
      break;
   }
   default:
      _mesa_error(ctx, GL_INVALID_ENUM, "%s", api_name);
      values[0] = -1;
      break;
   }
}

static int
find_compat_subroutine(struct gl_shader *sh, const struct glsl_type *type)
{
   int i, j;

   for (i = 0; i < sh->NumSubroutineFunctions; i++) {
      struct gl_subroutine_function *fn = &sh->SubroutineFunctions[i];
      for (j = 0; j < fn->num_compat_types; j++) {
         if (fn->types[j] == type)
            return i;
      }
   }
   return 0;
}

static void
_mesa_shader_init_subroutine_defaults(struct gl_shader *sh)
{
   int i, j;

   for (i = 0; i < sh->NumSubroutineUniformRemapTable; i++) {
      struct gl_uniform_storage *uni = sh->SubroutineUniformRemapTable[i];
      int uni_count;
      int val;

      if (!uni)
         continue;
      uni_count = uni->array_elements ? uni->array_elements : 1;
      val = find_compat_subroutine(sh, uni->type);

      for (j = 0; j < uni_count; j++)
         memcpy(&uni->storage[j], &val, sizeof(int));

      _mesa_propagate_uniforms_to_driver_storage(uni, 0, uni_count);
   }
}

void
_mesa_shader_program_init_subroutine_defaults(struct gl_shader_program *shProg)
{
   int i;

   if (!shProg)
      return;

   for (i = 0; i < MESA_SHADER_STAGES; i++) {
      if (!shProg->_LinkedShaders[i])
         continue;

      _mesa_shader_init_subroutine_defaults(shProg->_LinkedShaders[i]);
   }
}