/*
 * 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
 */


#include <errno.h>
#include <stdbool.h>
#include <c99_alloca.h>

#include "main/glheader.h"
#include "main/context.h"
#include "main/enums.h"
#include "main/glspirv.h"
#include "main/hash.h"
#include "main/mtypes.h"
#include "main/pipelineobj.h"
#include "main/program_binary.h"
#include "main/shaderapi.h"
#include "main/shaderobj.h"
#include "main/state.h"
#include "main/transformfeedback.h"
#include "main/uniforms.h"
#include "compiler/glsl/builtin_functions.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"
#include "util/crc32.h"
#include "util/os_file.h"
#include "util/simple_list.h"
#include "util/u_string.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, "cache_fb"))
         flags |= GLSL_CACHE_FALLBACK;
      if (strstr(env, "cache_info"))
         flags |= GLSL_CACHE_INFO;
      if (strstr(env, "nopvert"))
         flags |= GLSL_NOP_VERT;
      if (strstr(env, "nopfrag"))
         flags |= GLSL_NOP_FRAG;
      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;
}

/**
 * Memoized version of getenv("MESA_SHADER_CAPTURE_PATH").
 */
const char *
_mesa_get_shader_capture_path(void)
{
   static bool read_env_var = false;
   static const char *path = NULL;

   if (!read_env_var) {
      path = getenv("MESA_SHADER_CAPTURE_PATH");
      read_env_var = true;
   }

   return path;
}

/**
 * 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;
   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)
{
   for (int i = 0; i < MESA_SHADER_STAGES; i++) {
      _mesa_reference_program(ctx, &ctx->Shader.CurrentProgram[i], NULL);
      _mesa_reference_shader_program(ctx,
                                     &ctx->Shader.ReferencedPrograms[i],
                                     NULL);
      free(ctx->SubroutineIndex[i].IndexPtr);
      ctx->SubroutineIndex[i].IndexPtr = 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);
}


/**
 * 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, struct gl_shader_program *shProg,
              struct gl_shader *sh)
{
   GLuint n = shProg->NumShaders;

   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 void
attach_shader_err(struct gl_context *ctx, GLuint program, GLuint shader,
                  const char *caller)
{
   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, caller);
   if (!shProg)
      return;

   sh = _mesa_lookup_shader_err(ctx, shader, caller);
   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, "%s", caller);
         return;
      } else if (same_type_disallowed &&
                 shProg->Shaders[i]->Stage == sh->Stage) {
        /* 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, "%s", caller);
         return;
      }
   }

   attach_shader(ctx, shProg, sh);
}

static void
attach_shader_no_error(struct gl_context *ctx, GLuint program, GLuint shader)
{
   struct gl_shader_program *shProg;
   struct gl_shader *sh;

   shProg = _mesa_lookup_shader_program(ctx, program);
   sh = _mesa_lookup_shader(ctx, shader);

   attach_shader(ctx, shProg, sh);
}

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

   _mesa_HashLockMutex(ctx->Shared->ShaderObjects);
   name = _mesa_HashFindFreeKeyBlock(ctx->Shared->ShaderObjects, 1);
   sh = _mesa_new_shader(name, _mesa_shader_enum_to_shader_stage(type));
   sh->Type = type;
   _mesa_HashInsertLocked(ctx->Shared->ShaderObjects, name, sh, true);
   _mesa_HashUnlockMutex(ctx->Shared->ShaderObjects);

   return name;
}


static GLuint
create_shader_err(struct gl_context *ctx, GLenum type, const char *caller)
{
   if (!_mesa_validate_shader_target(ctx, type)) {
      _mesa_error(ctx, GL_INVALID_ENUM, "%s(%s)",
                  caller, _mesa_enum_to_string(type));
      return 0;
   }

   return create_shader(ctx, type);
}


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, true);

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

   if (!no_error) {
      shProg = _mesa_lookup_shader_program_err(ctx, program, "glDetachShader");
      if (!shProg)
         return;
   } else {
      shProg = _mesa_lookup_shader_program(ctx, program);
   }

   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;

#ifndef NDEBUG
         /* sanity check - make sure the new list's entries are sensible */
         for (j = 0; j < shProg->NumShaders; j++) {
            assert(shProg->Shaders[j]->Stage == MESA_SHADER_VERTEX ||
                   shProg->Shaders[j]->Stage == MESA_SHADER_TESS_CTRL ||
                   shProg->Shaders[j]->Stage == MESA_SHADER_TESS_EVAL ||
                   shProg->Shaders[j]->Stage == MESA_SHADER_GEOMETRY ||
                   shProg->Shaders[j]->Stage == MESA_SHADER_FRAGMENT);
            assert(shProg->Shaders[j]->RefCount > 0);
         }
#endif

         return;
      }
   }

   /* not found */
   if (!no_error) {
      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;
   }
}


static void
detach_shader_error(struct gl_context *ctx, GLuint program, GLuint shader)
{
   detach_shader(ctx, program, shader, false);
}


static void
detach_shader_no_error(struct gl_context *ctx, GLuint program, GLuint shader)
{
   detach_shader(ctx, program, shader, true);
}


/**
 * Return list of shaders attached to shader program.
 * \param objOut  returns GLuint ids
 * \param handleOut  returns GLhandleARB handles
 */
static void
get_attached_shaders(struct gl_context *ctx, GLuint program, GLsizei maxCount,
                     GLsizei *countOut, GLuint *objOut, GLhandleARB *handleOut)
{
   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++) {
         if (objOut) {
            objOut[i] = shProg->Shaders[i]->Name;
         }

         if (handleOut) {
            handleOut[i] = (GLhandleARB) shProg->Shaders[i]->Name;
         }
      }
      if (countOut) {
         *countOut = 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->data->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->data->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->data->LinkStatus &&
       shProg->_LinkedShaders[MESA_SHADER_TESS_EVAL] != NULL) {
      return true;
   }

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

/**
 * Return the length of a string, or 0 if the pointer passed in is NULL
 */
static size_t strlen_or_zero(const char *s)
{
   return s ? strlen(s) : 0;
}

/**
 * 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_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_COMPLETION_STATUS_ARB:
      if (ctx->Driver.GetShaderProgramCompletionStatus)
         *params = ctx->Driver.GetShaderProgramCompletionStatus(ctx, shProg);
      else
         *params = GL_TRUE;
      return;
   case GL_LINK_STATUS:
      *params = shProg->data->LinkStatus ? GL_TRUE : GL_FALSE;
      return;
   case GL_VALIDATE_STATUS:
      *params = shProg->data->Validated;
      return;
   case GL_INFO_LOG_LENGTH:
      *params = (shProg->data->InfoLog && shProg->data->InfoLog[0] != '\0') ?
         strlen(shProg->data->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->data->NumUniformStorage - shProg->data->NumHiddenUniforms;
      for (*params = 0, i = 0; i < num_uniforms; i++) {
         if (!shProg->data->UniformStorage[i].is_shader_storage)
            (*params)++;
      }
      return;
   }
   case GL_ACTIVE_UNIFORM_MAX_LENGTH: {
      unsigned i;
      GLint max_len = 0;
      const unsigned num_uniforms =
         shProg->data->NumUniformStorage - shProg->data->NumHiddenUniforms;

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

         /* From ARB_gl_spirv spec:
          *
          *   "If pname is ACTIVE_UNIFORM_MAX_LENGTH, the length of the
          *    longest active uniform name, including a null terminator, is
          *    returned. If no active uniforms exist, zero is returned. If no
          *    name reflection information is available, one is returned."
          *
          * We are setting 0 here, as below it will add 1 for the NUL character.
          */
         const GLint base_len =
            strlen_or_zero(shProg->data->UniformStorage[i].name);

	 /* 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 = base_len + 1 +
            ((shProg->data->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;

      /* Check first if there are transform feedback varyings specified in the
       * shader (ARB_enhanced_layouts). If there isn't any, return the number of
       * varyings specified using the API.
       */
      if (shProg->last_vert_prog &&
          shProg->last_vert_prog->sh.LinkedTransformFeedback->NumVarying > 0)
         *params =
            shProg->last_vert_prog->sh.LinkedTransformFeedback->NumVarying;
      else
         *params = shProg->TransformFeedback.NumVarying;
      return;
   case GL_TRANSFORM_FEEDBACK_VARYING_MAX_LENGTH: {
      unsigned i;
      GLint max_len = 0;
      bool in_shader_varyings;
      int num_varying;

      if (!has_xfb)
         break;

      /* Check first if there are transform feedback varyings specified in the
       * shader (ARB_enhanced_layouts). If there isn't any, use the ones
       * specified using the API.
       */
      in_shader_varyings = shProg->last_vert_prog &&
         shProg->last_vert_prog->sh.LinkedTransformFeedback->NumVarying > 0;

      num_varying = in_shader_varyings ?
         shProg->last_vert_prog->sh.LinkedTransformFeedback->NumVarying :
         shProg->TransformFeedback.NumVarying;

      for (i = 0; i < num_varying; i++) {
         const char *name = in_shader_varyings ?
            shProg->last_vert_prog->sh.LinkedTransformFeedback->Varyings[i].Name
            : shProg->TransformFeedback.VaryingNames[i];

         /* Add one for the terminating NUL character. We have to use
          * strlen_or_zero, as for shaders constructed from SPIR-V binaries,
          * it is possible that no name reflection information is available.
          */
         const GLint len = strlen_or_zero(name) + 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_gs)
         break;
      if (check_gs_query(ctx, shProg)) {
         *params = shProg->_LinkedShaders[MESA_SHADER_GEOMETRY]->
            Program->info.gs.vertices_out;
      }
      return;
   case GL_GEOMETRY_SHADER_INVOCATIONS:
      if (!has_gs ||
          (_mesa_is_desktop_gl(ctx) && !ctx->Extensions.ARB_gpu_shader5)) {
         break;
      }
      if (check_gs_query(ctx, shProg)) {
         *params = shProg->_LinkedShaders[MESA_SHADER_GEOMETRY]->
            Program->info.gs.invocations;
      }
      return;
   case GL_GEOMETRY_INPUT_TYPE:
      if (!has_gs)
         break;
      if (check_gs_query(ctx, shProg)) {
         *params = shProg->_LinkedShaders[MESA_SHADER_GEOMETRY]->
            Program->info.gs.input_primitive;
      }
      return;
   case GL_GEOMETRY_OUTPUT_TYPE:
      if (!has_gs)
         break;
      if (check_gs_query(ctx, shProg)) {
         *params = shProg->_LinkedShaders[MESA_SHADER_GEOMETRY]->
            Program->info.gs.output_primitive;
      }
      return;
   case GL_ACTIVE_UNIFORM_BLOCK_MAX_NAME_LENGTH: {
      unsigned i;
      GLint max_len = 0;

      if (!has_ubo)
         break;

      for (i = 0; i < shProg->data->NumUniformBlocks; i++) {
	 /* Add one for the terminating NUL character. Name can be NULL, in
          * that case, from ARB_gl_spirv:
          *   "If pname is ACTIVE_UNIFORM_BLOCK_MAX_NAME_LENGTH, the length of
          *    the longest active uniform block name, including the null
          *    terminator, is returned. If no active uniform blocks exist,
          *    zero is returned. If no name reflection information is
          *    available, one is returned."
	  */
         const GLint len =
            strlen_or_zero(shProg->data->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->data->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->BinaryRetrievableHint;
      return;
   case GL_PROGRAM_BINARY_LENGTH:
      if (ctx->Const.NumProgramBinaryFormats == 0 || !shProg->data->LinkStatus) {
         *params = 0;
      } else {
         _mesa_get_program_binary_length(ctx, shProg, params);
      }
      return;
   case GL_ACTIVE_ATOMIC_COUNTER_BUFFERS:
      if (!ctx->Extensions.ARB_shader_atomic_counters)
         break;

      *params = shProg->data->NumAtomicBuffers;
      return;
   case GL_COMPUTE_WORK_GROUP_SIZE: {
      int i;
      if (!_mesa_has_compute_shaders(ctx))
         break;
      if (!shProg->data->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->_LinkedShaders[MESA_SHADER_COMPUTE]->
            Program->info.cs.local_size[i];
      return;
   }
   case GL_PROGRAM_SEPARABLE:
      /* If the program has not been linked, return initial value 0. */
      *params = (shProg->data->LinkStatus == LINKING_FAILURE) ? 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->_LinkedShaders[MESA_SHADER_TESS_CTRL]->
            Program->info.tess.tcs_vertices_out;
      }
      return;
   case GL_TESS_GEN_MODE:
      if (!has_tess)
         break;
      if (check_tes_query(ctx, shProg)) {
         *params = shProg->_LinkedShaders[MESA_SHADER_TESS_EVAL]->
            Program->info.tess.primitive_mode;
      }
      return;
   case GL_TESS_GEN_SPACING:
      if (!has_tess)
         break;
      if (check_tes_query(ctx, shProg)) {
         const struct gl_linked_shader *tes =
            shProg->_LinkedShaders[MESA_SHADER_TESS_EVAL];
         switch (tes->Program->info.tess.spacing) {
         case TESS_SPACING_EQUAL:
            *params = GL_EQUAL;
            break;
         case TESS_SPACING_FRACTIONAL_ODD:
            *params = GL_FRACTIONAL_ODD;
            break;
         case TESS_SPACING_FRACTIONAL_EVEN:
            *params = GL_FRACTIONAL_EVEN;
            break;
         case TESS_SPACING_UNSPECIFIED:
            *params = 0;
            break;
         }
      }
      return;
   case GL_TESS_GEN_VERTEX_ORDER:
      if (!has_tess)
         break;
      if (check_tes_query(ctx, shProg)) {
         *params = shProg->_LinkedShaders[MESA_SHADER_TESS_EVAL]->
            Program->info.tess.ccw ? GL_CCW : GL_CW;
         }
      return;
   case GL_TESS_GEN_POINT_MODE:
      if (!has_tess)
         break;
      if (check_tes_query(ctx, shProg)) {
         *params = shProg->_LinkedShaders[MESA_SHADER_TESS_EVAL]->
            Program->info.tess.point_mode ? GL_TRUE : GL_FALSE;
      }
      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_COMPLETION_STATUS_ARB:
      /* _mesa_glsl_compile_shader is not offloaded to other threads. */
      *params = GL_TRUE;
      return;
   case GL_COMPILE_STATUS:
      *params = shader->CompileStatus ? GL_TRUE : GL_FALSE;
      break;
   case GL_INFO_LOG_LENGTH:
      *params = (shader->InfoLog && shader->InfoLog[0] != '\0') ?
         strlen(shader->InfoLog) + 1 : 0;
      break;
   case GL_SHADER_SOURCE_LENGTH:
      *params = shader->Source ? strlen((char *) shader->Source) + 1 : 0;
      break;
   case GL_SPIR_V_BINARY_ARB:
      *params = (shader->spirv_data != NULL);
      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->data->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
set_shader_source(struct gl_shader *sh, const GLchar *source)
{
   assert(sh);

   /* The GL_ARB_gl_spirv spec adds the following to the end of the description
    * of ShaderSource:
    *
    *   "If <shader> was previously associated with a SPIR-V module (via the
    *    ShaderBinary command), that association is broken. Upon successful
    *    completion of this command the SPIR_V_BINARY_ARB state of <shader>
    *    is set to FALSE."
    */
   _mesa_shader_spirv_data_reference(&sh->spirv_data, NULL);

   if (sh->CompileStatus == COMPILE_SKIPPED && !sh->FallbackSource) {
      /* If shader was previously compiled back-up the source in case of cache
       * fallback.
       */
      sh->FallbackSource = sh->Source;
      sh->Source = source;
   } else {
      /* free old shader source string and install new one */
      free((void *)sh->Source);
      sh->Source = source;
   }

#ifdef DEBUG
   sh->SourceChecksum = util_hash_crc32(sh->Source, strlen(sh->Source));
#endif
}

static void
ensure_builtin_types(struct gl_context *ctx)
{
   if (!ctx->shader_builtin_ref) {
      _mesa_glsl_builtin_functions_init_or_ref();
      ctx->shader_builtin_ref = true;
   }
}

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

   /* The GL_ARB_gl_spirv spec says:
    *
    *    "Add a new error for the CompileShader command:
    *
    *      An INVALID_OPERATION error is generated if the SPIR_V_BINARY_ARB
    *      state of <shader> is TRUE."
    */
   if (sh->spirv_data) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "glCompileShader(SPIR-V)");
      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 = COMPILE_FAILURE;
   } 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);
      }

      ensure_builtin_types(ctx);

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

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

      if (ctx->_Shader->Flags & GLSL_DUMP) {
         if (sh->CompileStatus) {
            if (sh->ir) {
               _mesa_log("GLSL IR for shader %d:\n", sh->Name);
               _mesa_print_ir(_mesa_get_log_file(), sh->ir, NULL);
            } else {
               _mesa_log("No GLSL IR for shader %d (shader may be from "
                         "cache)\n", sh->Name);
            }
            _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);
      }
   }
}


struct update_programs_in_pipeline_params
{
   struct gl_context *ctx;
   struct gl_shader_program *shProg;
};

static void
update_programs_in_pipeline(void *data, void *userData)
{
   struct update_programs_in_pipeline_params *params =
      (struct update_programs_in_pipeline_params *) userData;
   struct gl_pipeline_object *obj = (struct gl_pipeline_object *) data;

   for (unsigned stage = 0; stage < MESA_SHADER_STAGES; stage++) {
      if (obj->CurrentProgram[stage] &&
          obj->CurrentProgram[stage]->Id == params->shProg->Name) {
         struct gl_program *prog = params->shProg->_LinkedShaders[stage]->Program;
         _mesa_use_program(params->ctx, stage, params->shProg, prog, obj);
      }
   }
}


/**
 * Link a program's shaders.
 */
static ALWAYS_INLINE void
link_program(struct gl_context *ctx, struct gl_shader_program *shProg,
             bool no_error)
{
   if (!shProg)
      return;

   if (!no_error) {
      /* 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;
      }
   }

   unsigned programs_in_use = 0;
   if (ctx->_Shader)
      for (unsigned stage = 0; stage < MESA_SHADER_STAGES; stage++) {
         if (ctx->_Shader->CurrentProgram[stage] &&
             ctx->_Shader->CurrentProgram[stage]->Id == shProg->Name) {
            programs_in_use |= 1 << stage;
         }
      }

   ensure_builtin_types(ctx);

   FLUSH_VERTICES(ctx, 0);
   _mesa_glsl_link_shader(ctx, shProg);

   /* From section 7.3 (Program Objects) of the OpenGL 4.5 spec:
    *
    *    "If LinkProgram or ProgramBinary successfully re-links a program
    *     object that is active for any shader stage, then the newly generated
    *     executable code will be installed as part of the current rendering
    *     state for all shader stages where the program is active.
    *     Additionally, the newly generated executable code is made part of
    *     the state of any program pipeline for all stages where the program
    *     is attached."
    */
   if (shProg->data->LinkStatus) {
      while (programs_in_use) {
         const int stage = u_bit_scan(&programs_in_use);

         struct gl_program *prog = NULL;
         if (shProg->_LinkedShaders[stage])
            prog = shProg->_LinkedShaders[stage]->Program;

         _mesa_use_program(ctx, stage, shProg, prog, ctx->_Shader);
      }

      if (ctx->Pipeline.Objects) {
         struct update_programs_in_pipeline_params params = {
            .ctx = ctx,
            .shProg = shProg
         };
         _mesa_HashWalk(ctx->Pipeline.Objects, update_programs_in_pipeline,
                        &params);
      }
   }

   /* Capture .shader_test files. */
   const char *capture_path = _mesa_get_shader_capture_path();
   if (shProg->Name != 0 && shProg->Name != ~0 && capture_path != NULL) {
      /* Find an unused filename. */
      FILE *file = NULL;
      char *filename = NULL;
      for (unsigned i = 0;; i++) {
         if (i) {
            filename = ralloc_asprintf(NULL, "%s/%u-%u.shader_test",
                                       capture_path, shProg->Name, i);
         } else {
            filename = ralloc_asprintf(NULL, "%s/%u.shader_test",
                                       capture_path, shProg->Name);
         }
         file = os_file_create_unique(filename, 0644);
         if (file)
            break;
         /* If we are failing for another reason than "this filename already
          * exists", we are likely to fail again with another filename, so
          * let's just give up */
         if (errno != EEXIST)
            break;
         ralloc_free(filename);
      }
      if (file) {
         fprintf(file, "[require]\nGLSL%s >= %u.%02u\n",
                 shProg->IsES ? " ES" : "",
                 shProg->data->Version / 100, shProg->data->Version % 100);
         if (shProg->SeparateShader)
            fprintf(file, "GL_ARB_separate_shader_objects\nSSO ENABLED\n");
         fprintf(file, "\n");

         for (unsigned i = 0; i < shProg->NumShaders; i++) {
            fprintf(file, "[%s shader]\n%s\n",
                    _mesa_shader_stage_to_string(shProg->Shaders[i]->Stage),
                    shProg->Shaders[i]->Source);
         }
         fclose(file);
      } else {
         _mesa_warning(ctx, "Failed to open %s", filename);
      }

      ralloc_free(filename);
   }

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

   _mesa_update_vertex_processing_mode(ctx);

   shProg->BinaryRetrievableHint = shProg->BinaryRetrievableHintPending;

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

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

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


static void
link_program_error(struct gl_context *ctx, struct gl_shader_program *shProg)
{
   link_program(ctx, shProg, false);
}


static void
link_program_no_error(struct gl_context *ctx, struct gl_shader_program *shProg)
{
   link_program(ctx, shProg, true);
}


void
_mesa_link_program(struct gl_context *ctx, struct gl_shader_program *shProg)
{
   link_program_error(ctx, shProg);
}


/**
 * 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++) {
#ifdef DEBUG
      printf("  %s shader %u, checksum %u\n",
             _mesa_shader_stage_to_string(shProg->Shaders[i]->Stage),
	     shProg->Shaders[i]->Name,
	     shProg->Shaders[i]->SourceChecksum);
#else
      printf("  %s shader %u\n",
             _mesa_shader_stage_to_string(shProg->Shaders[i]->Stage),
             shProg->Shaders[i]->Name);
#endif
   }
   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->data->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);
   }
}


/**
 * Use the named shader program for subsequent rendering.
 */
void
_mesa_use_shader_program(struct gl_context *ctx,
                         struct gl_shader_program *shProg)
{
   for (int i = 0; i < MESA_SHADER_STAGES; i++) {
      struct gl_program *new_prog = NULL;
      if (shProg && shProg->_LinkedShaders[i])
         new_prog = shProg->_LinkedShaders[i]->Program;
      _mesa_use_program(ctx, i, shProg, new_prog, &ctx->Shader);
   }
   _mesa_active_program(ctx, shProg, "glUseProgram");
}


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


void GLAPIENTRY
_mesa_AttachObjectARB_no_error(GLhandleARB program, GLhandleARB shader)
{
   GET_CURRENT_CONTEXT(ctx);
   attach_shader_no_error(ctx, program, shader);
}


void GLAPIENTRY
_mesa_AttachObjectARB(GLhandleARB program, GLhandleARB shader)
{
   GET_CURRENT_CONTEXT(ctx);
   attach_shader_err(ctx, program, shader, "glAttachObjectARB");
}


void GLAPIENTRY
_mesa_AttachShader_no_error(GLuint program, GLuint shader)
{
   GET_CURRENT_CONTEXT(ctx);
   attach_shader_no_error(ctx, program, shader);
}


void GLAPIENTRY
_mesa_AttachShader(GLuint program, GLuint shader)
{
   GET_CURRENT_CONTEXT(ctx);
   attach_shader_err(ctx, program, shader, "glAttachShader");
}


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_no_error(GLenum type)
{
   GET_CURRENT_CONTEXT(ctx);
   return create_shader(ctx, type);
}


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_err(ctx, type, "glCreateShader");
}


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


GLhandleARB GLAPIENTRY
_mesa_CreateShaderObjectARB(GLenum type)
{
   GET_CURRENT_CONTEXT(ctx);
   return create_shader_err(ctx, type, "glCreateShaderObjectARB");
}


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_no_error(GLhandleARB program, GLhandleARB shader)
{
   GET_CURRENT_CONTEXT(ctx);
   detach_shader_no_error(ctx, program, shader);
}


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


void GLAPIENTRY
_mesa_DetachShader_no_error(GLuint program, GLuint shader)
{
   GET_CURRENT_CONTEXT(ctx);
   detach_shader_no_error(ctx, program, shader);
}


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


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


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_no_error(GLuint programObj)
{
   GET_CURRENT_CONTEXT(ctx);

   struct gl_shader_program *shProg =
      _mesa_lookup_shader_program(ctx, programObj);
   link_program_no_error(ctx, shProg);
}


void GLAPIENTRY
_mesa_LinkProgram(GLuint programObj)
{
   GET_CURRENT_CONTEXT(ctx);

   if (MESA_VERBOSE & VERBOSE_API)
      _mesa_debug(ctx, "glLinkProgram %u\n", programObj);

   struct gl_shader_program *shProg =
      _mesa_lookup_shader_program_err(ctx, programObj, "glLinkProgram");
   link_program_error(ctx, shProg);
}

#ifdef ENABLE_SHADER_CACHE
/**
 * 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
 * <path>/<stage prefix>_<CHECKSUM>.arb
 */
static char *
construct_name(const gl_shader_stage stage, const char *source,
               const char *path)
{
   char sha[64];
   static const char *types[] = {
      "VS", "TC", "TE", "GS", "FS", "CS",
   };

   const char *format = strncmp(source, "!!ARB", 5) ? "glsl" : "arb";

   generate_sha1(source, sha);
   return ralloc_asprintf(NULL, "%s/%s_%s.%s", path, types[stage], sha, format);
}

/**
 * Write given shader source to a file in MESA_SHADER_DUMP_PATH.
 */
void
_mesa_dump_shader_source(const gl_shader_stage stage, const char *source)
{
   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;
   }

   char *name = construct_name(stage, source, dump_path);

   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));
   }
   ralloc_free(name);
}

/**
 * Read shader source code from a file.
 * Useful for debugging to override an app's shader.
 */
GLcharARB *
_mesa_read_shader_source(const gl_shader_stage stage, const char *source)
{
   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;
   }

   char *name = construct_name(stage, source, read_path);
   f = fopen(name, "r");
   ralloc_free(name);
   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 /* ENABLE_SHADER_CACHE */

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

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

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

   /*
    * 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 (!no_error && 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';

#ifdef ENABLE_SHADER_CACHE
   GLcharARB *replacement;

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

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

   set_shader_source(sh, source);

   free(offsets);
}


void GLAPIENTRY
_mesa_ShaderSource_no_error(GLuint shaderObj, GLsizei count,
                            const GLchar *const *string, const GLint *length)
{
   GET_CURRENT_CONTEXT(ctx);
   shader_source(ctx, shaderObj, count, string, length, true);
}


void GLAPIENTRY
_mesa_ShaderSource(GLuint shaderObj, GLsizei count,
                   const GLchar *const *string, const GLint *length)
{
   GET_CURRENT_CONTEXT(ctx);
   shader_source(ctx, shaderObj, count, string, length, false);
}


static ALWAYS_INLINE void
use_program(GLuint program, bool no_error)
{
   GET_CURRENT_CONTEXT(ctx);
   struct gl_shader_program *shProg = NULL;

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

   if (no_error) {
      if (program) {
         shProg = _mesa_lookup_shader_program(ctx, program);
      }
   } else {
      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->data->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);
         }
      }
   }

   /* 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 (shProg) {
      /* Attach shader state to the binding point */
      _mesa_reference_pipeline_object(ctx, &ctx->_Shader, &ctx->Shader);
      /* Update the program */
      _mesa_use_shader_program(ctx, shProg);
   } else {
      /* Must be done first: detach the progam */
      _mesa_use_shader_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) {
         if (no_error)
            _mesa_BindProgramPipeline_no_error(ctx->Pipeline.Current->Name);
         else
            _mesa_BindProgramPipeline(ctx->Pipeline.Current->Name);
      }
   }

   _mesa_update_vertex_processing_mode(ctx);
}


void GLAPIENTRY
_mesa_UseProgram_no_error(GLuint program)
{
   use_program(program, true);
}


void GLAPIENTRY
_mesa_UseProgram(GLuint program)
{
   use_program(program, false);
}


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)
{
   GET_CURRENT_CONTEXT(ctx);

   if (ctx->shader_builtin_ref) {
      _mesa_glsl_builtin_functions_decref();
      ctx->shader_builtin_ref = false;
   }
}


/**
 * 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);
   struct gl_shader **sh;

   /* 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;
   }

   /* Get all shader objects at once so we can make the operation
    * all-or-nothing.
    */
   if (n > SIZE_MAX / sizeof(*sh)) {
      _mesa_error(ctx, GL_OUT_OF_MEMORY, "glShaderBinary(count)");
      return;
   }

   sh = alloca(sizeof(*sh) * (size_t)n);
   if (!sh) {
      _mesa_error(ctx, GL_OUT_OF_MEMORY, "glShaderBinary");
      return;
   }

   for (int i = 0; i < n; ++i) {
      sh[i] = _mesa_lookup_shader_err(ctx, shaders[i], "glShaderBinary");
      if (!sh[i])
         return;
   }

   if (binaryformat == GL_SHADER_BINARY_FORMAT_SPIR_V_ARB) {
      if (!ctx->Extensions.ARB_gl_spirv) {
         _mesa_error(ctx, GL_INVALID_OPERATION, "glShaderBinary(SPIR-V)");
      } else if (n > 0) {
         _mesa_spirv_shader_binary(ctx, (unsigned) n, sh, binary,
                                   (size_t) length);
      }

      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->data->LinkStatus) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "glGetProgramBinary(program %u not linked)",
                  shProg->Name);
      *length = 0;
      return;
   }

   if (ctx->Const.NumProgramBinaryFormats == 0) {
      *length = 0;
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "glGetProgramBinary(driver supports zero binary formats)");
   } else {
      _mesa_get_program_binary(ctx, shProg, bufSize, length, binaryFormat,
                               binary);
      assert(*length == 0 || *binaryFormat == GL_PROGRAM_BINARY_FORMAT_MESA);
   }
}

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;

   _mesa_clear_shader_program_data(ctx, shProg);
   shProg->data = _mesa_create_shader_program_data();

   /* 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;
   }

   if (ctx->Const.NumProgramBinaryFormats == 0 ||
       binaryFormat != GL_PROGRAM_BINARY_FORMAT_MESA) {
      /* 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->data->LinkStatus = LINKING_FAILURE;
      _mesa_error(ctx, GL_INVALID_ENUM, "glProgramBinary");
   } else {
      _mesa_program_binary(ctx, shProg, binaryFormat, binary, length);
   }
}


static ALWAYS_INLINE void
program_parameteri(struct gl_context *ctx, struct gl_shader_program *shProg,
                   GLuint pname, GLint value, bool no_error)
{
   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 (!no_error && 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 resolution 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->BinaryRetrievableHintPending = 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 (!no_error && value != GL_TRUE && value != GL_FALSE) {
         goto invalid_value;
      }
      shProg->SeparateShader = value;
      return;

   default:
      if (!no_error) {
         _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 GLAPIENTRY
_mesa_ProgramParameteri_no_error(GLuint program, GLenum pname, GLint value)
{
   GET_CURRENT_CONTEXT(ctx);

   struct gl_shader_program *shProg = _mesa_lookup_shader_program(ctx, program);
   program_parameteri(ctx, shProg, pname, value, true);
}


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;

   program_parameteri(ctx, shProg, pname, value, false);
}


void
_mesa_use_program(struct gl_context *ctx, gl_shader_stage stage,
                  struct gl_shader_program *shProg, struct gl_program *prog,
                  struct gl_pipeline_object *shTarget)
{
   struct gl_program **target;

   target = &shTarget->CurrentProgram[stage];
   if (prog) {
      _mesa_program_init_subroutine_defaults(ctx, prog);
   }

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

      _mesa_reference_shader_program(ctx,
                                     &shTarget->ReferencedPrograms[stage],
                                     shProg);
      _mesa_reference_program(ctx, target, prog);
      _mesa_update_allow_draw_out_of_order(ctx);
      if (stage == MESA_SHADER_VERTEX)
         _mesa_update_vertex_processing_mode(ctx);
      return;
   }

}


/**
 * Copy program-specific data generated by linking from the gl_shader_program
 * object to the gl_program object referred to by the gl_linked_shader.
 *
 * This function expects _mesa_reference_program() to have been previously
 * called setting the gl_linked_shaders program reference.
 */
void
_mesa_copy_linked_program_data(const struct gl_shader_program *src,
                               struct gl_linked_shader *dst_sh)
{
   assert(dst_sh->Program);

   struct gl_program *dst = dst_sh->Program;

   dst->info.separate_shader = src->SeparateShader;

   switch (dst_sh->Stage) {
   case MESA_SHADER_GEOMETRY: {
      dst->info.gs.vertices_in = src->Geom.VerticesIn;
      dst->info.gs.uses_end_primitive = src->Geom.UsesEndPrimitive;
      dst->info.gs.active_stream_mask = src->Geom.ActiveStreamMask;
      break;
   }
   case MESA_SHADER_FRAGMENT: {
      dst->info.fs.depth_layout = src->FragDepthLayout;
      break;
   }
   case MESA_SHADER_COMPUTE: {
      dst->info.cs.shared_size = 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_err(ctx, type, "glCreateShaderProgramv");
   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_err(ctx, program, shader, "glCreateShaderProgramv");
	    _mesa_link_program(ctx, shProg);
	    detach_shader_error(ctx, program, shader);

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

      delete_shader(ctx, shader);
   }

   return program;
}


/**
 * For GL_ARB_tessellation_shader
 */
void GLAPIENTRY
_mesa_PatchParameteri_no_error(GLenum pname, GLint value)
{
   GET_CURRENT_CONTEXT(ctx);
   FLUSH_VERTICES(ctx, 0);
   ctx->TessCtrlProgram.patch_vertices = value;
}


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;
   }

   FLUSH_VERTICES(ctx, 0);
   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_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_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_linked_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_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;
   }

   struct gl_program *p = shProg->_LinkedShaders[stage]->Program;
   if (index >= p->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 < p->sh.NumSubroutineFunctions; i++) {
            struct gl_subroutine_function *fn = &p->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_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_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";
   gl_shader_stage stage;
   int i;

   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);
   struct gl_program *p = ctx->_Shader->CurrentProgram[stage];
   if (!p) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }

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

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

      if (!flushed) {
         _mesa_flush_vertices_for_uniforms(ctx, uni);
         flushed = true;
      }

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

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

         for (f = 0; f < p->sh.NumSubroutineFunctions; f++) {
            if (p->sh.SubroutineFunctions[f].index == indices[j])
               subfn = &p->sh.SubroutineFunctions[f];
         }

         if (!subfn) {
            continue;
         }

         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;
         }

         ctx->SubroutineIndex[p->info.stage].IndexPtr[j] = indices[j];
      }
      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";
   gl_shader_stage stage;

   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);
   struct gl_program *p = ctx->_Shader->CurrentProgram[stage];
   if (!p) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      return;
   }

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

   *params = ctx->SubroutineIndex[p->info.stage].IndexPtr[location];
}


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_linked_shader *sh;
   gl_shader_stage stage;

   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];

   /* ARB_shader_subroutine doesn't ask the program to be linked, or list any
    * INVALID_OPERATION in the case of not be linked.
    *
    * And for some pnames, like GL_ACTIVE_SUBROUTINE_UNIFORMS, you can ask the
    * same info using other specs (ARB_program_interface_query), without the
    * need of the program to be linked, being the value for that case 0.
    *
    * But at the same time, some other methods require the program to be
    * linked for pname related to locations, so it would be inconsistent to
    * not do the same here. So we are:
    *   * Return GL_INVALID_OPERATION if not linked only for locations.
    *   * Setting a default value of 0, to be returned if not linked.
    */
   if (!sh) {
      values[0] = 0;
      if (pname == GL_ACTIVE_SUBROUTINE_UNIFORM_LOCATIONS) {
         _mesa_error(ctx, GL_INVALID_OPERATION, "%s", api_name);
      }
      return;
   }

   struct gl_program *p = sh->Program;
   switch (pname) {
   case GL_ACTIVE_SUBROUTINES:
      values[0] = p->sh.NumSubroutineFunctions;
      break;
   case GL_ACTIVE_SUBROUTINE_UNIFORM_LOCATIONS:
      values[0] = p->sh.NumSubroutineUniformRemapTable;
      break;
   case GL_ACTIVE_SUBROUTINE_UNIFORMS:
      values[0] = p->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 < p->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 < p->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;
   }
}

/* This is simple list entry that will be used to hold a list of string
 * tokens of a parsed shader include path.
 */
struct sh_incl_path_entry
{
   struct sh_incl_path_entry *next;
   struct sh_incl_path_entry *prev;

   char *path;
};

/* Nodes of the shader include tree */
struct sh_incl_path_ht_entry
{
   struct hash_table *path;
   char *shader_source;
};

struct shader_includes {
   /* Array to hold include paths given to glCompileShaderIncludeARB() */
   struct sh_incl_path_entry **include_paths;
   size_t num_include_paths;
   size_t relative_path_cursor;

   /* Root hash table holding the shader include tree */
   struct hash_table *shader_include_tree;
};

void
_mesa_init_shader_includes(struct gl_shared_state *shared)
{
   shared->ShaderIncludes = calloc(1, sizeof(struct shader_includes));
   shared->ShaderIncludes->shader_include_tree =
      _mesa_hash_table_create(NULL, _mesa_hash_string,
                              _mesa_key_string_equal);
}

size_t
_mesa_get_shader_include_cursor(struct gl_shared_state *shared)
{
   return shared->ShaderIncludes->relative_path_cursor;
}

void
_mesa_set_shader_include_cursor(struct gl_shared_state *shared, size_t cursor)
{
   shared->ShaderIncludes->relative_path_cursor = cursor;
}

static void
destroy_shader_include(struct hash_entry *entry)
{
   struct sh_incl_path_ht_entry *sh_incl_ht_entry =
      (struct sh_incl_path_ht_entry *) entry->data;

   _mesa_hash_table_destroy(sh_incl_ht_entry->path, destroy_shader_include);
   free(sh_incl_ht_entry->shader_source);
   free(sh_incl_ht_entry);
}

void
_mesa_destroy_shader_includes(struct gl_shared_state *shared)
{
   _mesa_hash_table_destroy(shared->ShaderIncludes->shader_include_tree,
                            destroy_shader_include);
   free(shared->ShaderIncludes);
}

static bool
valid_path_format(const char *str, bool relative_path)
{
   int i = 0;

   if (!str[i] || (!relative_path && str[i] != '/'))
      return false;

   i++;

   while (str[i]) {
      const char c = str[i++];
      if (('A' <= c && c <= 'Z') ||
          ('a' <= c && c <= 'z') ||
          ('0' <= c && c <= '9'))
         continue;

      if (c == '/') {
         if (str[i - 2] == '/')
            return false;

         continue;
      }

      if (strchr("^. _+*%[](){}|&~=!:;,?-", c) == NULL)
         return false;
  }

  if (str[i - 1] == '/')
     return false;

  return true;
}


static bool
validate_and_tokenise_sh_incl(struct gl_context *ctx,
                              void *mem_ctx,
                              struct sh_incl_path_entry **path_list,
                              char *full_path, bool error_check)
{
   bool relative_path = ctx->Shared->ShaderIncludes->num_include_paths;

   if (!valid_path_format(full_path, relative_path)) {
      if (error_check) {
         _mesa_error(ctx, GL_INVALID_VALUE,
                     "glNamedStringARB(invalid name %s)", full_path);
      }
      return false;
   }

   char *save_ptr = NULL;
   char *path_str = strtok_r(full_path, "/", &save_ptr);

   *path_list = rzalloc(mem_ctx, struct sh_incl_path_entry);

   make_empty_list(*path_list);

   while (path_str != NULL) {
      if (strlen(path_str) == 0) {
         if (error_check) {
            _mesa_error(ctx, GL_INVALID_VALUE,
                        "glNamedStringARB(invalid name %s)", full_path);
         }

         return false;
      }

      if (strcmp(path_str, ".") == 0) {
         /* Do nothing */
      } else if (strcmp(path_str, "..") == 0) {
         struct sh_incl_path_entry *last = last_elem(*path_list);
         remove_from_list(last);
      } else {
         struct sh_incl_path_entry *path =
            rzalloc(mem_ctx, struct sh_incl_path_entry);

         path->path = strdup(path_str);
         insert_at_tail(*path_list, path);
      }

      path_str = strtok_r(NULL, "/", &save_ptr);
   }

   return true;
}

static struct sh_incl_path_ht_entry *
lookup_shader_include(struct gl_context *ctx, char *path,
                      bool error_check)
{
   void *mem_ctx = ralloc_context(NULL);
   struct sh_incl_path_entry *path_list;

   if (!validate_and_tokenise_sh_incl(ctx, mem_ctx, &path_list, path,
                                      error_check)) {
      ralloc_free(mem_ctx);
      return NULL;
   }

   struct sh_incl_path_ht_entry *sh_incl_ht_entry = NULL;
   struct hash_table *path_ht =
      ctx->Shared->ShaderIncludes->shader_include_tree;

   size_t count = ctx->Shared->ShaderIncludes->num_include_paths;
   bool relative_path = path[0] != '/';

   size_t i = ctx->Shared->ShaderIncludes->relative_path_cursor;
   bool use_cursor = ctx->Shared->ShaderIncludes->relative_path_cursor;

   do {
      struct sh_incl_path_entry *entry;

      if (relative_path) {
next_relative_path:
         {
            struct sh_incl_path_entry *rel_path_list =
               ctx->Shared->ShaderIncludes->include_paths[i];
            foreach(entry, rel_path_list) {
               struct hash_entry *ht_entry =
                  _mesa_hash_table_search(path_ht, entry->path);

               if (!ht_entry) {
                  /* Reset search path and skip to the next include path */
                  path_ht = ctx->Shared->ShaderIncludes->shader_include_tree;
                  sh_incl_ht_entry = NULL;
                  if (use_cursor) {
                     i = 0;
                     use_cursor = false;

                     goto next_relative_path;
                  }
                  i++;
                  if (i < count)
                     goto next_relative_path;
                  else
                     break;
               } else {
                  sh_incl_ht_entry =
                    (struct sh_incl_path_ht_entry *) ht_entry->data;
               }

               path_ht = sh_incl_ht_entry->path;
            }
         }
      }

      foreach(entry, path_list) {
         struct hash_entry *ht_entry =
            _mesa_hash_table_search(path_ht, entry->path);

         if (!ht_entry) {
            /* Reset search path and skip to the next include path */
            path_ht = ctx->Shared->ShaderIncludes->shader_include_tree;
            sh_incl_ht_entry = NULL;
            if (use_cursor) {
               i = 0;
               use_cursor = false;

               break;
            }
            i++;
            break;
         } else {

            sh_incl_ht_entry =
               (struct sh_incl_path_ht_entry *) ht_entry->data;
         }

         path_ht = sh_incl_ht_entry->path;
      }

      if (i < count &&
          (sh_incl_ht_entry == NULL || !sh_incl_ht_entry->shader_source))
         continue;

      /* If we get here then we have found a matching path or exahusted our
       * relative search paths.
       */
      ctx->Shared->ShaderIncludes->relative_path_cursor = i;
      break;
   } while (i < count);

   ralloc_free(mem_ctx);

   return sh_incl_ht_entry;
}

const char *
_mesa_lookup_shader_include(struct gl_context *ctx, char *path,
                            bool error_check)
{
   struct sh_incl_path_ht_entry *shader_include =
      lookup_shader_include(ctx, path, error_check);

   return shader_include ? shader_include->shader_source : NULL;
}

static char *
copy_string(struct gl_context *ctx, const char *str, int str_len,
            const char *caller)
{
   if (!str) {
      _mesa_error(ctx, GL_INVALID_VALUE, "%s(NULL string)", caller);
      return NULL;
   }

   char *cp;
   if (str_len == -1)
      cp = strdup(str);
   else {
      cp = calloc(sizeof(char), str_len + 1);
      memcpy(cp, str, str_len);
   }

   return cp;
}

GLvoid GLAPIENTRY
_mesa_NamedStringARB(GLenum type, GLint namelen, const GLchar *name,
                     GLint stringlen, const GLchar *string)
{
   GET_CURRENT_CONTEXT(ctx);
   const char *caller = "glNamedStringARB";

   if (type != GL_SHADER_INCLUDE_ARB) {
      _mesa_error(ctx, GL_INVALID_VALUE, "%s(invalid type)", caller);
      return;
   }

   char *name_cp = copy_string(ctx, name, namelen, caller);
   char *string_cp = copy_string(ctx, string, stringlen, caller);
   if (!name_cp || !string_cp) {
      free(string_cp);
      free(name_cp);
      return;
   }

   void *mem_ctx = ralloc_context(NULL);
   struct sh_incl_path_entry *path_list;

   if (!validate_and_tokenise_sh_incl(ctx, mem_ctx, &path_list, name_cp,
                                      true)) {
      free(string_cp);
      free(name_cp);
      ralloc_free(mem_ctx);
      return;
   }

   mtx_lock(&ctx->Shared->ShaderIncludeMutex);

   struct hash_table *path_ht =
      ctx->Shared->ShaderIncludes->shader_include_tree;

   struct sh_incl_path_entry *entry;
   foreach(entry, path_list) {
      struct hash_entry *ht_entry =
         _mesa_hash_table_search(path_ht, entry->path);

      struct sh_incl_path_ht_entry *sh_incl_ht_entry;
      if (!ht_entry) {
         sh_incl_ht_entry = calloc(1, sizeof(struct sh_incl_path_ht_entry));
         sh_incl_ht_entry->path =
            _mesa_hash_table_create(NULL, _mesa_hash_string,
                                    _mesa_key_string_equal);
         _mesa_hash_table_insert(path_ht, entry->path, sh_incl_ht_entry);
      } else {
         sh_incl_ht_entry = (struct sh_incl_path_ht_entry *) ht_entry->data;
      }

      path_ht = sh_incl_ht_entry->path;

      if (last_elem(path_list) == entry) {
         free(sh_incl_ht_entry->shader_source);
         sh_incl_ht_entry->shader_source = string_cp;
      }
   }

   mtx_unlock(&ctx->Shared->ShaderIncludeMutex);

   free(name_cp);
   ralloc_free(mem_ctx);
}

GLvoid GLAPIENTRY
_mesa_DeleteNamedStringARB(GLint namelen, const GLchar *name)
{
   GET_CURRENT_CONTEXT(ctx);
   const char *caller = "glDeleteNamedStringARB";

   char *name_cp = copy_string(ctx, name, namelen, caller);
   if (!name_cp)
      return;

   struct sh_incl_path_ht_entry *shader_include =
      lookup_shader_include(ctx, name_cp, true);

   if (!shader_include) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "%s(no string associated with path %s)", caller, name_cp);
      free(name_cp);
      return;
   }

   mtx_lock(&ctx->Shared->ShaderIncludeMutex);

   free(shader_include->shader_source);
   shader_include->shader_source = NULL;

   mtx_unlock(&ctx->Shared->ShaderIncludeMutex);

   free(name_cp);
}

GLvoid GLAPIENTRY
_mesa_CompileShaderIncludeARB(GLuint shader, GLsizei count,
                              const GLchar* const *path, const GLint *length)
{
   GET_CURRENT_CONTEXT(ctx);
   const char *caller = "glCompileShaderIncludeARB";

   if (count > 0 && path == NULL) {
      _mesa_error(ctx, GL_INVALID_VALUE, "%s(count > 0 && path == NULL)",
                  caller);
      return;
   }

   void *mem_ctx = ralloc_context(NULL);

   mtx_lock(&ctx->Shared->ShaderIncludeMutex);

   ctx->Shared->ShaderIncludes->include_paths =
      ralloc_array_size(mem_ctx, sizeof(struct sh_incl_path_entry *), count);

   for (size_t i = 0; i < count; i++) {
      char *path_cp = copy_string(ctx, path[i], length ? length[i] : -1,
                                  caller);
      if (!path_cp) {
         goto exit;
      }

      struct sh_incl_path_entry *path_list;

      if (!validate_and_tokenise_sh_incl(ctx, mem_ctx, &path_list, path_cp,
                                         true)) {
         free(path_cp);
         goto exit;
      }

      ctx->Shared->ShaderIncludes->include_paths[i] = path_list;

      free(path_cp);
   }

   /* We must set this *after* all calls to validate_and_tokenise_sh_incl()
    * are done as we use this to decide if we need to check the start of the
    * path for a '/'
    */
   ctx->Shared->ShaderIncludes->num_include_paths = count;

   struct gl_shader *sh = _mesa_lookup_shader(ctx, shader);
   if (!sh) {
      _mesa_error(ctx, GL_INVALID_OPERATION, "%s(shader)", caller);
      goto exit;
   }

   _mesa_compile_shader(ctx, sh);

exit:
   ctx->Shared->ShaderIncludes->num_include_paths = 0;
   ctx->Shared->ShaderIncludes->relative_path_cursor = 0;
   ctx->Shared->ShaderIncludes->include_paths = NULL;

   mtx_unlock(&ctx->Shared->ShaderIncludeMutex);

   ralloc_free(mem_ctx);
}

GLboolean GLAPIENTRY
_mesa_IsNamedStringARB(GLint namelen, const GLchar *name)
{
   GET_CURRENT_CONTEXT(ctx);

   if (!name)
      return false;

   char *name_cp = copy_string(ctx, name, namelen, "");

   const char *source = _mesa_lookup_shader_include(ctx, name_cp, false);
   free(name_cp);

   if (!source)
      return false;

   return true;
}

GLvoid GLAPIENTRY
_mesa_GetNamedStringARB(GLint namelen, const GLchar *name, GLsizei bufSize,
                        GLint *stringlen, GLchar *string)
{
   GET_CURRENT_CONTEXT(ctx);
   const char *caller = "glGetNamedStringARB";

   char *name_cp = copy_string(ctx, name, namelen, caller);
   if (!name_cp)
      return;

   const char *source = _mesa_lookup_shader_include(ctx, name_cp, true);
   if (!source) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "%s(no string associated with path %s)", caller, name_cp);
      free(name_cp);
      return;
   }

   size_t size = MIN2(strlen(source), bufSize - 1);
   memcpy(string, source, size);
   string[size] = '\0';

   *stringlen = size;

   free(name_cp);
}

GLvoid GLAPIENTRY
_mesa_GetNamedStringivARB(GLint namelen, const GLchar *name,
                          GLenum pname, GLint *params)
{
   GET_CURRENT_CONTEXT(ctx);
   const char *caller = "glGetNamedStringivARB";

   char *name_cp = copy_string(ctx, name, namelen, caller);
   if (!name_cp)
      return;

   const char *source = _mesa_lookup_shader_include(ctx, name_cp, true);
   if (!source) {
      _mesa_error(ctx, GL_INVALID_OPERATION,
                  "%s(no string associated with path %s)", caller, name_cp);
      free(name_cp);
      return;
   }

   switch (pname) {
   case GL_NAMED_STRING_LENGTH_ARB:
      *params = strlen(source) + 1;
      break;
   case GL_NAMED_STRING_TYPE_ARB:
      *params = GL_SHADER_INCLUDE_ARB;
      break;
   default:
      _mesa_error(ctx, GL_INVALID_ENUM, "%s(pname)", caller);
      break;
   }

   free(name_cp);
}

static int
find_compat_subroutine(struct gl_program *p, const struct glsl_type *type)
{
   int i, j;

   for (i = 0; i < p->sh.NumSubroutineFunctions; i++) {
      struct gl_subroutine_function *fn = &p->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_write_subroutine_index(struct gl_context *ctx,
                                    struct gl_program *p)
{
   int i, j;

   if (p->sh.NumSubroutineUniformRemapTable == 0)
      return;

   i = 0;
   do {
      struct gl_uniform_storage *uni = p->sh.SubroutineUniformRemapTable[i];
      int uni_count;
      int val;

      if (!uni) {
         i++;
         continue;
      }

      uni_count = uni->array_elements ? uni->array_elements : 1;
      for (j = 0; j < uni_count; j++) {
         val = ctx->SubroutineIndex[p->info.stage].IndexPtr[i + j];
         memcpy(&uni->storage[j], &val, sizeof(int));
      }

      _mesa_propagate_uniforms_to_driver_storage(uni, 0, uni_count);
      i += uni_count;
   } while(i < p->sh.NumSubroutineUniformRemapTable);
}

void
_mesa_shader_write_subroutine_indices(struct gl_context *ctx,
                                      gl_shader_stage stage)
{
   if (ctx->_Shader->CurrentProgram[stage])
      _mesa_shader_write_subroutine_index(ctx,
                                          ctx->_Shader->CurrentProgram[stage]);
}

void
_mesa_program_init_subroutine_defaults(struct gl_context *ctx,
                                       struct gl_program *p)
{
   assert(p);

   struct gl_subroutine_index_binding *binding = &ctx->SubroutineIndex[p->info.stage];
   if (binding->NumIndex != p->sh.NumSubroutineUniformRemapTable) {
      binding->IndexPtr = realloc(binding->IndexPtr,
                                  p->sh.NumSubroutineUniformRemapTable * (sizeof(GLuint)));
      binding->NumIndex = p->sh.NumSubroutineUniformRemapTable;
   }

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

      if (!uni)
         continue;

      binding->IndexPtr[i] = find_compat_subroutine(p, uni->type);
   }
}