mesa: updates some comments in buffers.c
[mesa.git] / src / mesa / main / shader_query.cpp
index d2ca49b43a700bb4fa63a9bcc7b668dc25700e70..4967e4b1df1a2d10d76e63f2d557266de2b16c04 100644 (file)
  * \author Ian Romanick <ian.d.romanick@intel.com>
  */
 
+#include "main/context.h"
 #include "main/core.h"
-#include "glsl_symbol_table.h"
-#include "ir.h"
-#include "shaderobj.h"
-#include "program/hash_table.h"
-#include "../glsl/program.h"
-#include "uniforms.h"
 #include "main/enums.h"
+#include "main/shaderapi.h"
+#include "main/shaderobj.h"
+#include "main/uniforms.h"
+#include "compiler/glsl/glsl_symbol_table.h"
+#include "compiler/glsl/ir.h"
+#include "compiler/glsl/program.h"
+#include "program/hash_table.h"
+#include "util/strndup.h"
 
-extern "C" {
-#include "shaderapi.h"
-}
 
 static GLint
 program_resource_location(struct gl_shader_program *shProg,
-                          struct gl_program_resource *res, const char *name);
+                          struct gl_program_resource *res, const char *name,
+                          unsigned array_index);
 
 /**
  * Declare convenience functions to return resource data in a given type.
@@ -55,15 +56,16 @@ const type * RESOURCE_ ## name (gl_program_resource *res) { \
    return (type *) res->Data; \
 }
 
-DECL_RESOURCE_FUNC(VAR, ir_variable);
+DECL_RESOURCE_FUNC(VAR, gl_shader_variable);
 DECL_RESOURCE_FUNC(UBO, gl_uniform_block);
 DECL_RESOURCE_FUNC(UNI, gl_uniform_storage);
 DECL_RESOURCE_FUNC(ATC, gl_active_atomic_buffer);
 DECL_RESOURCE_FUNC(XFB, gl_transform_feedback_varying_info);
+DECL_RESOURCE_FUNC(SUB, gl_subroutine_function);
 
 void GLAPIENTRY
-_mesa_BindAttribLocation(GLhandleARB program, GLuint index,
-                            const GLcharARB *name)
+_mesa_BindAttribLocation(GLuint program, GLuint index,
+                         const GLchar *name)
 {
    GET_CURRENT_CONTEXT(ctx);
 
@@ -99,14 +101,14 @@ _mesa_BindAttribLocation(GLhandleARB program, GLuint index,
 }
 
 static bool
-is_active_attrib(const ir_variable *var)
+is_active_attrib(const gl_shader_variable *var)
 {
    if (!var)
       return false;
 
-   switch (var->data.mode) {
+   switch (var->mode) {
    case ir_var_shader_in:
-      return var->data.location != -1;
+      return var->location != -1;
 
    case ir_var_system_value:
       /* From GL 4.3 core spec, section 11.1.1 (Vertex Attributes):
@@ -114,9 +116,9 @@ is_active_attrib(const ir_variable *var)
        * are enumerated, including the special built-in inputs gl_VertexID
        * and gl_InstanceID."
        */
-      return var->data.location == SYSTEM_VALUE_VERTEX_ID ||
-             var->data.location == SYSTEM_VALUE_VERTEX_ID_ZERO_BASE ||
-             var->data.location == SYSTEM_VALUE_INSTANCE_ID;
+      return var->location == SYSTEM_VALUE_VERTEX_ID ||
+             var->location == SYSTEM_VALUE_VERTEX_ID_ZERO_BASE ||
+             var->location == SYSTEM_VALUE_INSTANCE_ID;
 
    default:
       return false;
@@ -124,9 +126,9 @@ is_active_attrib(const ir_variable *var)
 }
 
 void GLAPIENTRY
-_mesa_GetActiveAttrib(GLhandleARB program, GLuint desired_index,
-                         GLsizei maxLength, GLsizei * length, GLint * size,
-                         GLenum * type, GLcharARB * name)
+_mesa_GetActiveAttrib(GLuint program, GLuint desired_index,
+                      GLsizei maxLength, GLsizei * length, GLint * size,
+                      GLenum * type, GLchar * name)
 {
    GET_CURRENT_CONTEXT(ctx);
    struct gl_shader_program *shProg;
@@ -161,7 +163,7 @@ _mesa_GetActiveAttrib(GLhandleARB program, GLuint desired_index,
       return;
    }
 
-   const ir_variable *const var = RESOURCE_VAR(res);
+   const gl_shader_variable *const var = RESOURCE_VAR(res);
 
    if (!is_active_attrib(var))
       return;
@@ -172,8 +174,8 @@ _mesa_GetActiveAttrib(GLhandleARB program, GLuint desired_index,
     * consider gl_VertexIDMESA as gl_VertexID for purposes of checking
     * active attributes.
     */
-   if (var->data.mode == ir_var_system_value &&
-       var->data.location == SYSTEM_VALUE_VERTEX_ID_ZERO_BASE) {
+   if (var->mode == ir_var_system_value &&
+       var->location == SYSTEM_VALUE_VERTEX_ID_ZERO_BASE) {
       var_name = "gl_VertexID";
    }
 
@@ -188,65 +190,8 @@ _mesa_GetActiveAttrib(GLhandleARB program, GLuint desired_index,
                                   (GLint *) type, "glGetActiveAttrib");
 }
 
-/* Locations associated with shader variables (array or non-array) can be
- * queried using its base name or using the base name appended with the
- * valid array index. For example, in case of below vertex shader, valid
- * queries can be made to know the location of "xyz", "array", "array[0]",
- * "array[1]", "array[2]" and "array[3]". In this example index reurned
- * will be 0, 0, 0, 1, 2, 3 respectively.
- *
- * [Vertex Shader]
- * layout(location=0) in vec4 xyz;
- * layout(location=1) in vec4[4] array;
- * void main()
- * { }
- *
- * This requirement came up with the addition of ARB_program_interface_query
- * to OpenGL 4.3 specification. See page 101 (page 122 of the PDF) for details.
- *
- * This utility function is used by:
- * _mesa_GetAttribLocation
- * _mesa_GetFragDataLocation
- * _mesa_GetFragDataIndex
- *
- * Returns 0:
- *    if the 'name' string matches var->name.
- * Returns 'matched index':
- *    if the 'name' string matches var->name appended with valid array index.
- */
-int static inline
-get_matching_index(const ir_variable *const var, const char *name) {
-   unsigned idx = 0;
-   const char *const paren = strchr(name, '[');
-   const unsigned len = (paren != NULL) ? paren - name : strlen(name);
-
-   if (paren != NULL) {
-      if (!var->type->is_array())
-         return -1;
-
-      char *endptr;
-      idx = (unsigned) strtol(paren + 1, &endptr, 10);
-      const unsigned idx_len = endptr != (paren + 1) ? endptr - paren - 1 : 0;
-
-      /* Validate the sub string representing index in 'name' string */
-      if ((idx > 0 && paren[1] == '0') /* leading zeroes */
-          || (idx == 0 && idx_len > 1) /* all zeroes */
-          || paren[1] == ' ' /* whitespace */
-          || endptr[0] != ']' /* closing brace */
-          || endptr[1] != '\0' /* null char */
-          || idx_len == 0 /* missing index */
-          || idx >= var->type->length) /* exceeding array bound */
-         return -1;
-   }
-
-   if (strncmp(var->name, name, len) == 0 && var->name[len] == '\0')
-      return idx;
-
-   return -1;
-}
-
 GLint GLAPIENTRY
-_mesa_GetAttribLocation(GLhandleARB program, const GLcharARB * name)
+_mesa_GetAttribLocation(GLuint program, const GLchar * name)
 {
    GET_CURRENT_CONTEXT(ctx);
    struct gl_shader_program *const shProg =
@@ -270,13 +215,15 @@ _mesa_GetAttribLocation(GLhandleARB program, const GLcharARB * name)
    if (shProg->_LinkedShaders[MESA_SHADER_VERTEX] == NULL)
       return -1;
 
+   unsigned array_index = 0;
    struct gl_program_resource *res =
-      _mesa_program_resource_find_name(shProg, GL_PROGRAM_INPUT, name);
+      _mesa_program_resource_find_name(shProg, GL_PROGRAM_INPUT, name,
+                                       &array_index);
 
    if (!res)
       return -1;
 
-   GLint loc = program_resource_location(shProg, res, name);
+   GLint loc = program_resource_location(shProg, res, name, array_index);
 
    /* The extra check against against 0 is made because of builtin-attribute
     * locations that have offset applied. Function program_resource_location
@@ -454,13 +401,15 @@ _mesa_GetFragDataLocation(GLuint program, const GLchar *name)
    if (shProg->_LinkedShaders[MESA_SHADER_FRAGMENT] == NULL)
       return -1;
 
+   unsigned array_index = 0;
    struct gl_program_resource *res =
-      _mesa_program_resource_find_name(shProg, GL_PROGRAM_OUTPUT, name);
+      _mesa_program_resource_find_name(shProg, GL_PROGRAM_OUTPUT, name,
+                                       &array_index);
 
    if (!res)
       return -1;
 
-   GLint loc = program_resource_location(shProg, res, name);
+   GLint loc = program_resource_location(shProg, res, name, array_index);
 
    /* The extra check against against 0 is made because of builtin-attribute
     * locations that have offset applied. Function program_resource_location
@@ -478,16 +427,40 @@ _mesa_GetFragDataLocation(GLuint program, const GLchar *name)
 const char*
 _mesa_program_resource_name(struct gl_program_resource *res)
 {
+   const gl_shader_variable *var;
    switch (res->Type) {
    case GL_UNIFORM_BLOCK:
+   case GL_SHADER_STORAGE_BLOCK:
       return RESOURCE_UBO(res)->Name;
    case GL_TRANSFORM_FEEDBACK_VARYING:
       return RESOURCE_XFB(res)->Name;
    case GL_PROGRAM_INPUT:
+      var = RESOURCE_VAR(res);
+      /* Special case gl_VertexIDMESA -> gl_VertexID. */
+      if (var->mode == ir_var_system_value &&
+          var->location == SYSTEM_VALUE_VERTEX_ID_ZERO_BASE) {
+         return "gl_VertexID";
+      }
+   /* fallthrough */
    case GL_PROGRAM_OUTPUT:
       return RESOURCE_VAR(res)->name;
    case GL_UNIFORM:
+   case GL_BUFFER_VARIABLE:
       return RESOURCE_UNI(res)->name;
+   case GL_VERTEX_SUBROUTINE_UNIFORM:
+   case GL_GEOMETRY_SUBROUTINE_UNIFORM:
+   case GL_FRAGMENT_SUBROUTINE_UNIFORM:
+   case GL_COMPUTE_SUBROUTINE_UNIFORM:
+   case GL_TESS_CONTROL_SUBROUTINE_UNIFORM:
+   case GL_TESS_EVALUATION_SUBROUTINE_UNIFORM:
+      return RESOURCE_UNI(res)->name + MESA_SUBROUTINE_PREFIX_LEN;
+   case GL_VERTEX_SUBROUTINE:
+   case GL_GEOMETRY_SUBROUTINE:
+   case GL_FRAGMENT_SUBROUTINE:
+   case GL_COMPUTE_SUBROUTINE:
+   case GL_TESS_CONTROL_SUBROUTINE:
+   case GL_TESS_EVALUATION_SUBROUTINE:
+      return RESOURCE_SUB(res)->name;
    default:
       assert(!"support for resource type not implemented");
    }
@@ -504,11 +477,31 @@ _mesa_program_resource_array_size(struct gl_program_resource *res)
              RESOURCE_XFB(res)->Size : 0;
    case GL_PROGRAM_INPUT:
    case GL_PROGRAM_OUTPUT:
-      return RESOURCE_VAR(res)->data.max_array_access;
+      return RESOURCE_VAR(res)->type->length;
    case GL_UNIFORM:
+   case GL_VERTEX_SUBROUTINE_UNIFORM:
+   case GL_GEOMETRY_SUBROUTINE_UNIFORM:
+   case GL_FRAGMENT_SUBROUTINE_UNIFORM:
+   case GL_COMPUTE_SUBROUTINE_UNIFORM:
+   case GL_TESS_CONTROL_SUBROUTINE_UNIFORM:
+   case GL_TESS_EVALUATION_SUBROUTINE_UNIFORM:
       return RESOURCE_UNI(res)->array_elements;
+   case GL_BUFFER_VARIABLE:
+      /* Unsized arrays */
+      if (RESOURCE_UNI(res)->array_stride > 0 &&
+          RESOURCE_UNI(res)->array_elements == 0)
+         return 1;
+      else
+         return RESOURCE_UNI(res)->array_elements;
+   case GL_VERTEX_SUBROUTINE:
+   case GL_GEOMETRY_SUBROUTINE:
+   case GL_FRAGMENT_SUBROUTINE:
+   case GL_COMPUTE_SUBROUTINE:
+   case GL_TESS_CONTROL_SUBROUTINE:
+   case GL_TESS_EVALUATION_SUBROUTINE:
    case GL_ATOMIC_COUNTER_BUFFER:
    case GL_UNIFORM_BLOCK:
+   case GL_SHADER_STORAGE_BLOCK:
       return 0;
    default:
       assert(!"support for resource type not implemented");
@@ -516,27 +509,31 @@ _mesa_program_resource_array_size(struct gl_program_resource *res)
    return 0;
 }
 
-static int
-array_index_of_resource(struct gl_program_resource *res,
-                        const char *name)
+/**
+ * Checks if array subscript is valid and if so sets array_index.
+ */
+static bool
+valid_array_index(const GLchar *name, unsigned *array_index)
 {
-   assert(res->Data);
+   long idx = 0;
+   const GLchar *out_base_name_end;
 
-   switch (res->Type) {
-   case GL_PROGRAM_INPUT:
-   case GL_PROGRAM_OUTPUT:
-      return get_matching_index(RESOURCE_VAR(res), name);
-   default:
-      assert(!"support for resource type not implemented");
-      return -1;
-   }
+   idx = parse_program_resource_name(name, &out_base_name_end);
+   if (idx < 0)
+      return false;
+
+   if (array_index)
+      *array_index = idx;
+
+   return true;
 }
 
 /* Find a program resource with specific name in given interface.
  */
 struct gl_program_resource *
 _mesa_program_resource_find_name(struct gl_shader_program *shProg,
-                                 GLenum programInterface, const char *name)
+                                 GLenum programInterface, const char *name,
+                                 unsigned *array_index)
 {
    struct gl_program_resource *res = shProg->ProgramResourceList;
    for (unsigned i = 0; i < shProg->NumProgramResourceList; i++, res++) {
@@ -546,27 +543,91 @@ _mesa_program_resource_find_name(struct gl_shader_program *shProg,
       /* Resource basename. */
       const char *rname = _mesa_program_resource_name(res);
       unsigned baselen = strlen(rname);
+      unsigned baselen_without_array_index = baselen;
+      const char *rname_last_square_bracket = strrchr(rname, '[');
+      bool found = false;
+      bool rname_has_array_index_zero = false;
+      /* From ARB_program_interface_query spec:
+       *
+       * "uint GetProgramResourceIndex(uint program, enum programInterface,
+       *                               const char *name);
+       *  [...]
+       *  If <name> exactly matches the name string of one of the active
+       *  resources for <programInterface>, the index of the matched resource is
+       *  returned. Additionally, if <name> would exactly match the name string
+       *  of an active resource if "[0]" were appended to <name>, the index of
+       *  the matched resource is returned. [...]"
+       *
+       * "A string provided to GetProgramResourceLocation or
+       * GetProgramResourceLocationIndex is considered to match an active variable
+       * if:
+       *
+       *  * the string exactly matches the name of the active variable;
+       *
+       *  * if the string identifies the base name of an active array, where the
+       *    string would exactly match the name of the variable if the suffix
+       *    "[0]" were appended to the string; [...]"
+       */
+      /* Remove array's index from interface block name comparison only if
+       * array's index is zero and the resulting string length is the same
+       * than the provided name's length.
+       */
+      if (rname_last_square_bracket) {
+         baselen_without_array_index -= strlen(rname_last_square_bracket);
+         rname_has_array_index_zero =
+            (strncmp(rname_last_square_bracket, "[0]\0", 4) == 0) &&
+            (baselen_without_array_index == strlen(name));
+      }
 
-      switch (programInterface) {
-      case GL_TRANSFORM_FEEDBACK_VARYING:
-      case GL_UNIFORM_BLOCK:
-      case GL_UNIFORM:
-         if (strncmp(rname, name, baselen) == 0) {
+      if (strncmp(rname, name, baselen) == 0)
+         found = true;
+      else if (rname_has_array_index_zero &&
+               strncmp(rname, name, baselen_without_array_index) == 0)
+         found = true;
+
+      if (found) {
+         switch (programInterface) {
+         case GL_UNIFORM_BLOCK:
+         case GL_SHADER_STORAGE_BLOCK:
             /* Basename match, check if array or struct. */
-            if (name[baselen] == '\0' ||
+            if (rname_has_array_index_zero ||
+                name[baselen] == '\0' ||
                 name[baselen] == '[' ||
                 name[baselen] == '.') {
                return res;
             }
+            break;
+         case GL_TRANSFORM_FEEDBACK_VARYING:
+         case GL_BUFFER_VARIABLE:
+         case GL_UNIFORM:
+         case GL_VERTEX_SUBROUTINE_UNIFORM:
+         case GL_GEOMETRY_SUBROUTINE_UNIFORM:
+         case GL_FRAGMENT_SUBROUTINE_UNIFORM:
+         case GL_COMPUTE_SUBROUTINE_UNIFORM:
+         case GL_TESS_CONTROL_SUBROUTINE_UNIFORM:
+         case GL_TESS_EVALUATION_SUBROUTINE_UNIFORM:
+         case GL_VERTEX_SUBROUTINE:
+         case GL_GEOMETRY_SUBROUTINE:
+         case GL_FRAGMENT_SUBROUTINE:
+         case GL_COMPUTE_SUBROUTINE:
+         case GL_TESS_CONTROL_SUBROUTINE:
+         case GL_TESS_EVALUATION_SUBROUTINE:
+            if (name[baselen] == '.') {
+               return res;
+            }
+            /* fall-through */
+         case GL_PROGRAM_INPUT:
+         case GL_PROGRAM_OUTPUT:
+            if (name[baselen] == '\0') {
+               return res;
+            } else if (name[baselen] == '[' &&
+                valid_array_index(name, array_index)) {
+               return res;
+            }
+            break;
+         default:
+            assert(!"not implemented for given interface");
          }
-         break;
-      case GL_PROGRAM_INPUT:
-      case GL_PROGRAM_OUTPUT:
-         if (array_index_of_resource(res, name) >= 0)
-            return res;
-         break;
-      default:
-         assert(!"not implemented for given interface");
       }
    }
    return NULL;
@@ -598,16 +659,37 @@ _mesa_program_resource_index(struct gl_shader_program *shProg,
       return GL_INVALID_INDEX;
 
    switch (res->Type) {
-   case GL_UNIFORM_BLOCK:
-      return RESOURCE_UBO(res)- shProg->UniformBlocks;
    case GL_ATOMIC_COUNTER_BUFFER:
       return RESOURCE_ATC(res) - shProg->AtomicBuffers;
+   case GL_VERTEX_SUBROUTINE:
+   case GL_GEOMETRY_SUBROUTINE:
+   case GL_FRAGMENT_SUBROUTINE:
+   case GL_COMPUTE_SUBROUTINE:
+   case GL_TESS_CONTROL_SUBROUTINE:
+   case GL_TESS_EVALUATION_SUBROUTINE:
+      return RESOURCE_SUB(res)->index;
+   case GL_UNIFORM_BLOCK:
+   case GL_SHADER_STORAGE_BLOCK:
    case GL_TRANSFORM_FEEDBACK_VARYING:
    default:
       return calc_resource_index(shProg, res);
    }
 }
 
+/**
+ * Find a program resource that points to given data.
+ */
+static struct gl_program_resource*
+program_resource_find_data(struct gl_shader_program *shProg, void *data)
+{
+   struct gl_program_resource *res = shProg->ProgramResourceList;
+   for (unsigned i = 0; i < shProg->NumProgramResourceList; i++, res++) {
+      if (res->Data == data)
+         return res;
+   }
+   return NULL;
+}
+
 /* Find a program resource with specific index in given interface.
  */
 struct gl_program_resource *
@@ -624,6 +706,7 @@ _mesa_program_resource_find_index(struct gl_shader_program *shProg,
       switch (res->Type) {
       case GL_UNIFORM_BLOCK:
       case GL_ATOMIC_COUNTER_BUFFER:
+      case GL_SHADER_STORAGE_BLOCK:
          if (_mesa_program_resource_index(shProg, res) == index)
             return res;
          break;
@@ -631,6 +714,19 @@ _mesa_program_resource_find_index(struct gl_shader_program *shProg,
       case GL_PROGRAM_INPUT:
       case GL_PROGRAM_OUTPUT:
       case GL_UNIFORM:
+      case GL_VERTEX_SUBROUTINE_UNIFORM:
+      case GL_GEOMETRY_SUBROUTINE_UNIFORM:
+      case GL_FRAGMENT_SUBROUTINE_UNIFORM:
+      case GL_COMPUTE_SUBROUTINE_UNIFORM:
+      case GL_TESS_CONTROL_SUBROUTINE_UNIFORM:
+      case GL_TESS_EVALUATION_SUBROUTINE_UNIFORM:
+      case GL_VERTEX_SUBROUTINE:
+      case GL_GEOMETRY_SUBROUTINE:
+      case GL_FRAGMENT_SUBROUTINE:
+      case GL_COMPUTE_SUBROUTINE:
+      case GL_TESS_CONTROL_SUBROUTINE:
+      case GL_TESS_EVALUATION_SUBROUTINE:
+      case GL_BUFFER_VARIABLE:
          if (++idx == (int) index)
             return res;
          break;
@@ -641,6 +737,61 @@ _mesa_program_resource_find_index(struct gl_shader_program *shProg,
    return NULL;
 }
 
+/* Function returns if resource name is expected to have index
+ * appended into it.
+ *
+ *
+ * Page 61 (page 73 of the PDF) in section 2.11 of the OpenGL ES 3.0
+ * spec says:
+ *
+ *     "If the active uniform is an array, the uniform name returned in
+ *     name will always be the name of the uniform array appended with
+ *     "[0]"."
+ *
+ * The same text also appears in the OpenGL 4.2 spec.  It does not,
+ * however, appear in any previous spec.  Previous specifications are
+ * ambiguous in this regard.  However, either name can later be passed
+ * to glGetUniformLocation (and related APIs), so there shouldn't be any
+ * harm in always appending "[0]" to uniform array names.
+ *
+ * Geometry shader stage has different naming convention where the 'normal'
+ * condition is an array, therefore for variables referenced in geometry
+ * stage we do not add '[0]'.
+ *
+ * Note, that TCS outputs and TES inputs should not have index appended
+ * either.
+ */
+static bool
+add_index_to_name(struct gl_program_resource *res)
+{
+   bool add_index = !((res->Type == GL_PROGRAM_INPUT &&
+                       res->StageReferences & (1 << MESA_SHADER_GEOMETRY |
+                                               1 << MESA_SHADER_TESS_CTRL |
+                                               1 << MESA_SHADER_TESS_EVAL)) ||
+                      (res->Type == GL_PROGRAM_OUTPUT &&
+                       res->StageReferences & 1 << MESA_SHADER_TESS_CTRL));
+
+   /* Transform feedback varyings have array index already appended
+    * in their names.
+    */
+   if (res->Type == GL_TRANSFORM_FEEDBACK_VARYING)
+      add_index = false;
+
+   return add_index;
+}
+
+/* Get name length of a program resource. This consists of
+ * base name + 3 for '[0]' if resource is an array.
+ */
+extern unsigned
+_mesa_program_resource_name_len(struct gl_program_resource *res)
+{
+   unsigned length = strlen(_mesa_program_resource_name(res));
+   if (_mesa_program_resource_array_size(res) && add_index_to_name(res))
+      length += 3;
+   return length;
+}
+
 /* Get full name of a program resource.
  */
 bool
@@ -676,30 +827,7 @@ _mesa_get_program_resource_name(struct gl_shader_program *shProg,
 
    _mesa_copy_string(name, bufSize, length, _mesa_program_resource_name(res));
 
-   /* Page 61 (page 73 of the PDF) in section 2.11 of the OpenGL ES 3.0
-    * spec says:
-    *
-    *     "If the active uniform is an array, the uniform name returned in
-    *     name will always be the name of the uniform array appended with
-    *     "[0]"."
-    *
-    * The same text also appears in the OpenGL 4.2 spec.  It does not,
-    * however, appear in any previous spec.  Previous specifications are
-    * ambiguous in this regard.  However, either name can later be passed
-    * to glGetUniformLocation (and related APIs), so there shouldn't be any
-    * harm in always appending "[0]" to uniform array names.
-    *
-    * Geometry shader stage has different naming convention where the 'normal'
-    * condition is an array, therefore for variables referenced in geometry
-    * stage we do not add '[0]'.
-    *
-    * Note, that TCS outputs and TES inputs should not have index appended
-    * either.
-    */
-   bool add_index = !(((programInterface == GL_PROGRAM_INPUT) &&
-                       res->StageReferences & (1 << MESA_SHADER_GEOMETRY)));
-
-   if (add_index && _mesa_program_resource_array_size(res)) {
+   if (_mesa_program_resource_array_size(res) && add_index_to_name(res)) {
       int i;
 
       /* The comparison is strange because *length does *NOT* include the
@@ -716,30 +844,48 @@ _mesa_get_program_resource_name(struct gl_shader_program *shProg,
 
 static GLint
 program_resource_location(struct gl_shader_program *shProg,
-                          struct gl_program_resource *res, const char *name)
+                          struct gl_program_resource *res, const char *name,
+                          unsigned array_index)
 {
-   unsigned index, offset;
-   int array_index = -1;
-
-   if (res->Type == GL_PROGRAM_INPUT || res->Type == GL_PROGRAM_OUTPUT) {
-      array_index = array_index_of_resource(res, name);
-      if (array_index < 0)
-         return -1;
-   }
+   /* Built-in locations should report GL_INVALID_INDEX. */
+   if (is_gl_identifier(name))
+      return GL_INVALID_INDEX;
 
    /* VERT_ATTRIB_GENERIC0 and FRAG_RESULT_DATA0 are decremented as these
     * offsets are used internally to differentiate between built-in attributes
     * and user-defined attributes.
     */
    switch (res->Type) {
-   case GL_PROGRAM_INPUT:
-      return RESOURCE_VAR(res)->data.location + array_index - VERT_ATTRIB_GENERIC0;
+   case GL_PROGRAM_INPUT: {
+      const gl_shader_variable *var = RESOURCE_VAR(res);
+
+      /* If the input is an array, fail if the index is out of bounds. */
+      if (array_index > 0
+          && array_index >= var->type->length) {
+         return -1;
+      }
+      return (var->location +
+             (array_index * var->type->without_array()->matrix_columns) -
+             VERT_ATTRIB_GENERIC0);
+   }
    case GL_PROGRAM_OUTPUT:
-      return RESOURCE_VAR(res)->data.location + array_index - FRAG_RESULT_DATA0;
+      /* If the output is an array, fail if the index is out of bounds. */
+      if (array_index > 0
+          && array_index >= RESOURCE_VAR(res)->type->length) {
+         return -1;
+      }
+      return RESOURCE_VAR(res)->location + array_index - FRAG_RESULT_DATA0;
    case GL_UNIFORM:
-      index = _mesa_get_uniform_location(shProg, name, &offset);
+      /* If the uniform is built-in, fail. */
+      if (RESOURCE_UNI(res)->builtin)
+         return -1;
 
-      if (index == GL_INVALID_INDEX)
+     /* From page 79 of the OpenGL 4.2 spec:
+      *
+      *     "A valid name cannot be a structure, an array of structures, or any
+      *     portion of a single vector or a matrix."
+      */
+      if (RESOURCE_UNI(res)->type->without_array()->is_record())
          return -1;
 
       /* From the GL_ARB_uniform_buffer_object spec:
@@ -753,9 +899,21 @@ program_resource_location(struct gl_shader_program *shProg,
           RESOURCE_UNI(res)->atomic_buffer_index != -1)
          return -1;
 
-      /* location in remap table + array element offset */
-      return RESOURCE_UNI(res)->remap_location + offset;
+      /* fallthrough */
+   case GL_VERTEX_SUBROUTINE_UNIFORM:
+   case GL_GEOMETRY_SUBROUTINE_UNIFORM:
+   case GL_FRAGMENT_SUBROUTINE_UNIFORM:
+   case GL_COMPUTE_SUBROUTINE_UNIFORM:
+   case GL_TESS_CONTROL_SUBROUTINE_UNIFORM:
+   case GL_TESS_EVALUATION_SUBROUTINE_UNIFORM:
+      /* If the uniform is an array, fail if the index is out of bounds. */
+      if (array_index > 0
+          && array_index >= RESOURCE_UNI(res)->array_elements) {
+         return -1;
+      }
 
+      /* location in remap table + array element offset */
+      return RESOURCE_UNI(res)->remap_location + array_index;
    default:
       return -1;
    }
@@ -763,22 +921,22 @@ program_resource_location(struct gl_shader_program *shProg,
 
 /**
  * Function implements following location queries:
- *    glGetAttribLocation
- *    glGetFragDataLocation
  *    glGetUniformLocation
  */
 GLint
 _mesa_program_resource_location(struct gl_shader_program *shProg,
                                 GLenum programInterface, const char *name)
 {
+   unsigned array_index = 0;
    struct gl_program_resource *res =
-      _mesa_program_resource_find_name(shProg, programInterface, name);
+      _mesa_program_resource_find_name(shProg, programInterface, name,
+                                       &array_index);
 
    /* Resource not found. */
    if (!res)
       return -1;
 
-   return program_resource_location(shProg, res, name);
+   return program_resource_location(shProg, res, name, array_index);
 }
 
 /**
@@ -790,13 +948,13 @@ _mesa_program_resource_location_index(struct gl_shader_program *shProg,
                                       GLenum programInterface, const char *name)
 {
    struct gl_program_resource *res =
-      _mesa_program_resource_find_name(shProg, programInterface, name);
+      _mesa_program_resource_find_name(shProg, programInterface, name, NULL);
 
    /* Non-existent variable or resource is not referenced by fragment stage. */
    if (!res || !(res->StageReferences & (1 << MESA_SHADER_FRAGMENT)))
       return -1;
 
-   return RESOURCE_VAR(res)->data.index;
+   return RESOURCE_VAR(res)->index;
 }
 
 static uint8_t
@@ -805,10 +963,16 @@ stage_from_enum(GLenum ref)
    switch (ref) {
    case GL_REFERENCED_BY_VERTEX_SHADER:
       return MESA_SHADER_VERTEX;
+   case GL_REFERENCED_BY_TESS_CONTROL_SHADER:
+      return MESA_SHADER_TESS_CTRL;
+   case GL_REFERENCED_BY_TESS_EVALUATION_SHADER:
+      return MESA_SHADER_TESS_EVAL;
    case GL_REFERENCED_BY_GEOMETRY_SHADER:
       return MESA_SHADER_GEOMETRY;
    case GL_REFERENCED_BY_FRAGMENT_SHADER:
       return MESA_SHADER_FRAGMENT;
+   case GL_REFERENCED_BY_COMPUTE_SHADER:
+      return MESA_SHADER_COMPUTE;
    default:
       assert(!"shader stage not supported");
       return MESA_SHADER_STAGES;
@@ -824,11 +988,15 @@ is_resource_referenced(struct gl_shader_program *shProg,
                        struct gl_program_resource *res,
                        GLuint index, uint8_t stage)
 {
+   /* First, check if we even have such a stage active. */
+   if (!shProg->_LinkedShaders[stage])
+      return false;
+
    if (res->Type == GL_ATOMIC_COUNTER_BUFFER)
       return RESOURCE_ATC(res)->StageReferences[stage];
 
-   if (res->Type == GL_UNIFORM_BLOCK)
-      return shProg->UniformBlockStageIndex[stage][index] != -1;
+   if (res->Type == GL_UNIFORM_BLOCK || res->Type == GL_SHADER_STORAGE_BLOCK)
+      return shProg->InterfaceBlockStageIndex[stage][index] != -1;
 
    return res->StageReferences & (1 << stage);
 }
@@ -840,7 +1008,8 @@ get_buffer_property(struct gl_shader_program *shProg,
 {
    GET_CURRENT_CONTEXT(ctx);
    if (res->Type != GL_UNIFORM_BLOCK &&
-       res->Type != GL_ATOMIC_COUNTER_BUFFER)
+       res->Type != GL_ATOMIC_COUNTER_BUFFER &&
+       res->Type != GL_SHADER_STORAGE_BLOCK)
       goto invalid_operation;
 
    if (res->Type == GL_UNIFORM_BLOCK) {
@@ -856,23 +1025,64 @@ get_buffer_property(struct gl_shader_program *shProg,
          for (unsigned i = 0; i < RESOURCE_UBO(res)->NumUniforms; i++) {
             const char *iname = RESOURCE_UBO(res)->Uniforms[i].IndexName;
             struct gl_program_resource *uni =
-               _mesa_program_resource_find_name(shProg, GL_UNIFORM, iname);
+               _mesa_program_resource_find_name(shProg, GL_UNIFORM, iname,
+                                                NULL);
             if (!uni)
                continue;
             (*val)++;
          }
          return 1;
-      case GL_ACTIVE_VARIABLES:
+      case GL_ACTIVE_VARIABLES: {
+         unsigned num_values = 0;
+         for (unsigned i = 0; i < RESOURCE_UBO(res)->NumUniforms; i++) {
+            const char *iname = RESOURCE_UBO(res)->Uniforms[i].IndexName;
+            struct gl_program_resource *uni =
+               _mesa_program_resource_find_name(shProg, GL_UNIFORM, iname,
+                                                NULL);
+            if (!uni)
+               continue;
+            *val++ =
+               _mesa_program_resource_index(shProg, uni);
+            num_values++;
+         }
+         return num_values;
+      }
+      }
+   } else if (res->Type == GL_SHADER_STORAGE_BLOCK) {
+      switch (prop) {
+      case GL_BUFFER_BINDING:
+         *val = RESOURCE_UBO(res)->Binding;
+         return 1;
+      case GL_BUFFER_DATA_SIZE:
+         *val = RESOURCE_UBO(res)->UniformBufferSize;
+         return 1;
+      case GL_NUM_ACTIVE_VARIABLES:
+         *val = 0;
+         for (unsigned i = 0; i < RESOURCE_UBO(res)->NumUniforms; i++) {
+            const char *iname = RESOURCE_UBO(res)->Uniforms[i].IndexName;
+            struct gl_program_resource *uni =
+               _mesa_program_resource_find_name(shProg, GL_BUFFER_VARIABLE,
+                                                iname, NULL);
+            if (!uni)
+               continue;
+            (*val)++;
+         }
+         return 1;
+      case GL_ACTIVE_VARIABLES: {
+         unsigned num_values = 0;
          for (unsigned i = 0; i < RESOURCE_UBO(res)->NumUniforms; i++) {
             const char *iname = RESOURCE_UBO(res)->Uniforms[i].IndexName;
             struct gl_program_resource *uni =
-               _mesa_program_resource_find_name(shProg, GL_UNIFORM, iname);
+               _mesa_program_resource_find_name(shProg, GL_BUFFER_VARIABLE,
+                                                iname, NULL);
             if (!uni)
                continue;
             *val++ =
                _mesa_program_resource_index(shProg, uni);
+            num_values++;
          }
-         return RESOURCE_UBO(res)->NumUniforms;
+         return num_values;
+      }
       }
    } else if (res->Type == GL_ATOMIC_COUNTER_BUFFER) {
       switch (prop) {
@@ -886,8 +1096,18 @@ get_buffer_property(struct gl_shader_program *shProg,
          *val = RESOURCE_ATC(res)->NumUniforms;
          return 1;
       case GL_ACTIVE_VARIABLES:
-         for (unsigned i = 0; i < RESOURCE_ATC(res)->NumUniforms; i++)
-            *val++ = RESOURCE_ATC(res)->Uniforms[i];
+         for (unsigned i = 0; i < RESOURCE_ATC(res)->NumUniforms; i++) {
+            /* Active atomic buffer contains index to UniformStorage. Find
+             * out gl_program_resource via data pointer and then calculate
+             * index of that uniform.
+             */
+            unsigned idx = RESOURCE_ATC(res)->Uniforms[i];
+            struct gl_program_resource *uni =
+               program_resource_find_data(shProg,
+                                          &shProg->UniformStorage[idx]);
+            assert(uni);
+            *val++ = _mesa_program_resource_index(shProg, uni);
+         }
          return RESOURCE_ATC(res)->NumUniforms;
       }
    }
@@ -895,8 +1115,8 @@ get_buffer_property(struct gl_shader_program *shProg,
 
 invalid_operation:
    _mesa_error(ctx, GL_INVALID_OPERATION, "%s(%s prop %s)", caller,
-               _mesa_lookup_enum_by_nr(res->Type),
-               _mesa_lookup_enum_by_nr(prop));
+               _mesa_enum_to_string(res->Type),
+               _mesa_enum_to_string(prop));
 
    return 0;
 }
@@ -912,17 +1132,24 @@ _mesa_program_resource_prop(struct gl_shader_program *shProg,
    if (res->Type != type)\
       goto invalid_operation;
 
+#define VALIDATE_TYPE_2(type1, type2)\
+   if (res->Type != type1 && res->Type != type2)\
+      goto invalid_operation;
+
    switch(prop) {
    case GL_NAME_LENGTH:
-      if (res->Type == GL_ATOMIC_COUNTER_BUFFER)
+      switch (res->Type) {
+      case GL_ATOMIC_COUNTER_BUFFER:
          goto invalid_operation;
-      /* Base name +3 if array '[0]' + terminator. */
-      *val = strlen(_mesa_program_resource_name(res)) +
-         (_mesa_program_resource_array_size(res) > 0 ? 3 : 0) + 1;
+      default:
+         /* Resource name length + terminator. */
+         *val = _mesa_program_resource_name_len(res) + 1;
+      }
       return 1;
    case GL_TYPE:
       switch (res->Type) {
       case GL_UNIFORM:
+      case GL_BUFFER_VARIABLE:
          *val = RESOURCE_UNI(res)->type->gl_type;
          return 1;
       case GL_PROGRAM_INPUT:
@@ -938,11 +1165,19 @@ _mesa_program_resource_prop(struct gl_shader_program *shProg,
    case GL_ARRAY_SIZE:
       switch (res->Type) {
       case GL_UNIFORM:
+      case GL_BUFFER_VARIABLE:
+         /* Test if a buffer variable is an array or an unsized array.
+          * Unsized arrays return zero as array size.
+          */
+         if (RESOURCE_UNI(res)->is_shader_storage &&
+             RESOURCE_UNI(res)->array_stride > 0)
+            *val = RESOURCE_UNI(res)->array_elements;
+         else
             *val = MAX2(RESOURCE_UNI(res)->array_elements, 1);
-            return 1;
+         return 1;
       case GL_PROGRAM_INPUT:
       case GL_PROGRAM_OUTPUT:
-         *val = MAX2(RESOURCE_VAR(res)->type->length, 1);
+         *val = MAX2(_mesa_program_resource_array_size(res), 1);
          return 1;
       case GL_TRANSFORM_FEEDBACK_VARYING:
          *val = MAX2(RESOURCE_XFB(res)->Size, 1);
@@ -951,23 +1186,23 @@ _mesa_program_resource_prop(struct gl_shader_program *shProg,
          goto invalid_operation;
       }
    case GL_OFFSET:
-      VALIDATE_TYPE(GL_UNIFORM);
+      VALIDATE_TYPE_2(GL_UNIFORM, GL_BUFFER_VARIABLE);
       *val = RESOURCE_UNI(res)->offset;
       return 1;
    case GL_BLOCK_INDEX:
-      VALIDATE_TYPE(GL_UNIFORM);
+      VALIDATE_TYPE_2(GL_UNIFORM, GL_BUFFER_VARIABLE);
       *val = RESOURCE_UNI(res)->block_index;
       return 1;
    case GL_ARRAY_STRIDE:
-      VALIDATE_TYPE(GL_UNIFORM);
+      VALIDATE_TYPE_2(GL_UNIFORM, GL_BUFFER_VARIABLE);
       *val = RESOURCE_UNI(res)->array_stride;
       return 1;
    case GL_MATRIX_STRIDE:
-      VALIDATE_TYPE(GL_UNIFORM);
+      VALIDATE_TYPE_2(GL_UNIFORM, GL_BUFFER_VARIABLE);
       *val = RESOURCE_UNI(res)->matrix_stride;
       return 1;
    case GL_IS_ROW_MAJOR:
-      VALIDATE_TYPE(GL_UNIFORM);
+      VALIDATE_TYPE_2(GL_UNIFORM, GL_BUFFER_VARIABLE);
       *val = RESOURCE_UNI(res)->row_major;
       return 1;
    case GL_ATOMIC_COUNTER_BUFFER_INDEX:
@@ -979,7 +1214,13 @@ _mesa_program_resource_prop(struct gl_shader_program *shProg,
    case GL_NUM_ACTIVE_VARIABLES:
    case GL_ACTIVE_VARIABLES:
       return get_buffer_property(shProg, res, prop, val, caller);
+   case GL_REFERENCED_BY_COMPUTE_SHADER:
+      if (!_mesa_has_compute_shaders(ctx))
+         goto invalid_enum;
+      /* fallthrough */
    case GL_REFERENCED_BY_VERTEX_SHADER:
+   case GL_REFERENCED_BY_TESS_CONTROL_SHADER:
+   case GL_REFERENCED_BY_TESS_EVALUATION_SHADER:
    case GL_REFERENCED_BY_GEOMETRY_SHADER:
    case GL_REFERENCED_BY_FRAGMENT_SHADER:
       switch (res->Type) {
@@ -987,6 +1228,8 @@ _mesa_program_resource_prop(struct gl_shader_program *shProg,
       case GL_PROGRAM_INPUT:
       case GL_PROGRAM_OUTPUT:
       case GL_UNIFORM_BLOCK:
+      case GL_BUFFER_VARIABLE:
+      case GL_SHADER_STORAGE_BLOCK:
       case GL_ATOMIC_COUNTER_BUFFER:
          *val = is_resource_referenced(shProg, res, index,
                                        stage_from_enum(prop));
@@ -1000,7 +1243,8 @@ _mesa_program_resource_prop(struct gl_shader_program *shProg,
       case GL_PROGRAM_INPUT:
       case GL_PROGRAM_OUTPUT:
          *val = program_resource_location(shProg, res,
-                                          _mesa_program_resource_name(res));
+                                          _mesa_program_resource_name(res),
+                                          0);
          return 1;
       default:
          goto invalid_operation;
@@ -1008,28 +1252,85 @@ _mesa_program_resource_prop(struct gl_shader_program *shProg,
    case GL_LOCATION_INDEX:
       if (res->Type != GL_PROGRAM_OUTPUT)
          goto invalid_operation;
-      *val = RESOURCE_VAR(res)->data.index;
+      *val = RESOURCE_VAR(res)->index;
+      return 1;
+
+   case GL_NUM_COMPATIBLE_SUBROUTINES:
+      if (res->Type != GL_VERTEX_SUBROUTINE_UNIFORM &&
+          res->Type != GL_FRAGMENT_SUBROUTINE_UNIFORM &&
+          res->Type != GL_GEOMETRY_SUBROUTINE_UNIFORM &&
+          res->Type != GL_COMPUTE_SUBROUTINE_UNIFORM &&
+          res->Type != GL_TESS_CONTROL_SUBROUTINE_UNIFORM &&
+          res->Type != GL_TESS_EVALUATION_SUBROUTINE_UNIFORM)
+         goto invalid_operation;
+      *val = RESOURCE_UNI(res)->num_compatible_subroutines;
+      return 1;
+   case GL_COMPATIBLE_SUBROUTINES: {
+      const struct gl_uniform_storage *uni;
+      struct gl_shader *sh;
+      unsigned count, i;
+      int j;
+
+      if (res->Type != GL_VERTEX_SUBROUTINE_UNIFORM &&
+          res->Type != GL_FRAGMENT_SUBROUTINE_UNIFORM &&
+          res->Type != GL_GEOMETRY_SUBROUTINE_UNIFORM &&
+          res->Type != GL_COMPUTE_SUBROUTINE_UNIFORM &&
+          res->Type != GL_TESS_CONTROL_SUBROUTINE_UNIFORM &&
+          res->Type != GL_TESS_EVALUATION_SUBROUTINE_UNIFORM)
+         goto invalid_operation;
+      uni = RESOURCE_UNI(res);
+
+      sh = shProg->_LinkedShaders[_mesa_shader_stage_from_subroutine_uniform(res->Type)];
+      count = 0;
+      for (i = 0; i < sh->NumSubroutineFunctions; i++) {
+         struct gl_subroutine_function *fn = &sh->SubroutineFunctions[i];
+         for (j = 0; j < fn->num_compat_types; j++) {
+            if (fn->types[j] == uni->type) {
+               val[count++] = i;
+               break;
+            }
+         }
+      }
+      return count;
+   }
+
+   case GL_TOP_LEVEL_ARRAY_SIZE:
+      VALIDATE_TYPE(GL_BUFFER_VARIABLE);
+      *val = RESOURCE_UNI(res)->top_level_array_size;
+      return 1;
+
+   case GL_TOP_LEVEL_ARRAY_STRIDE:
+      VALIDATE_TYPE(GL_BUFFER_VARIABLE);
+      *val = RESOURCE_UNI(res)->top_level_array_stride;
       return 1;
 
    /* GL_ARB_tessellation_shader */
    case GL_IS_PER_PATCH:
-   case GL_REFERENCED_BY_TESS_CONTROL_SHADER:
-   case GL_REFERENCED_BY_TESS_EVALUATION_SHADER:
-   /* GL_ARB_compute_shader */
-   case GL_REFERENCED_BY_COMPUTE_SHADER:
+      switch (res->Type) {
+      case GL_PROGRAM_INPUT:
+      case GL_PROGRAM_OUTPUT:
+         *val = RESOURCE_VAR(res)->patch;
+         return 1;
+      default:
+         goto invalid_operation;
+      }
    default:
-      _mesa_error(ctx, GL_INVALID_ENUM, "%s(%s prop %s)", caller,
-                  _mesa_lookup_enum_by_nr(res->Type),
-                  _mesa_lookup_enum_by_nr(prop));
-      return 0;
+      goto invalid_enum;
    }
 
 #undef VALIDATE_TYPE
+#undef VALIDATE_TYPE_2
+
+invalid_enum:
+   _mesa_error(ctx, GL_INVALID_ENUM, "%s(%s prop %s)", caller,
+               _mesa_enum_to_string(res->Type),
+               _mesa_enum_to_string(prop));
+   return 0;
 
 invalid_operation:
    _mesa_error(ctx, GL_INVALID_OPERATION, "%s(%s prop %s)", caller,
-               _mesa_lookup_enum_by_nr(res->Type),
-               _mesa_lookup_enum_by_nr(prop));
+               _mesa_enum_to_string(res->Type),
+               _mesa_enum_to_string(prop));
    return 0;
 }
 
@@ -1051,7 +1352,7 @@ _mesa_get_program_resourceiv(struct gl_shader_program *shProg,
    if (!res || bufSize < 0) {
       _mesa_error(ctx, GL_INVALID_VALUE,
                   "glGetProgramResourceiv(%s index %d bufSize %d)",
-                  _mesa_lookup_enum_by_nr(programInterface), index, bufSize);
+                  _mesa_enum_to_string(programInterface), index, bufSize);
       return;
    }
 
@@ -1074,3 +1375,144 @@ _mesa_get_program_resourceiv(struct gl_shader_program *shProg,
    if (length)
       *length = amount;
 }
+
+static bool
+validate_io(const struct gl_shader *producer,
+            const struct gl_shader *consumer, bool isES)
+{
+   assert(producer && consumer);
+   unsigned inputs = 0, outputs = 0;
+
+   /* From OpenGL ES 3.1 spec (Interface matching):
+    *
+    *    "An output variable is considered to match an input variable in the
+    *    subsequent shader if:
+    *
+    *    - the two variables match in name, type, and qualification; or
+    *    - the two variables are declared with the same location qualifier and
+    *      match in type and qualification.
+    *
+    *    ...
+    *
+    *    At an interface between program objects, the set of inputs and outputs
+    *    are considered to match exactly if and only if:
+    *
+    *    - Every declared input variable has a matching output, as described
+    *    above.
+    *
+    *    - There are no user-defined output variables declared without a
+    *    matching input variable declaration.
+    *
+    *    - All matched input and output variables have identical precision
+    *    qualification.
+    *
+    *    When the set of inputs and outputs on an interface between programs
+    *    matches exactly, all inputs are well-defined except when the
+    *    corresponding outputs were not written in the previous shader. However,
+    *    any mismatch between inputs and outputs will result in a validation
+    *    failure."
+    *
+    * OpenGL Core 4.5 spec includes same paragraph as above but without check
+    * for precision and the last 'validation failure' clause. Therefore
+    * behaviour is more relaxed, input and output amount is not required by the
+    * spec to be validated.
+    *
+    * FIXME: Update once Khronos spec bug #15331 is resolved.
+    * FIXME: Add validation by type, currently information loss during varying
+    * packing makes this challenging.
+    */
+
+   /* Currently no matching done for desktop. */
+   if (!isES)
+      return true;
+
+   /* For each output in a, find input in b and do any required checks. */
+   foreach_in_list(ir_instruction, out, producer->ir) {
+      ir_variable *out_var = out->as_variable();
+      if (!out_var || out_var->data.mode != ir_var_shader_out ||
+          is_gl_identifier(out_var->name))
+         continue;
+
+      outputs++;
+
+      inputs = 0;
+      foreach_in_list(ir_instruction, in, consumer->ir) {
+         ir_variable *in_var = in->as_variable();
+         if (!in_var || in_var->data.mode != ir_var_shader_in ||
+             is_gl_identifier(in_var->name))
+            continue;
+
+         inputs++;
+
+         /* Match by location qualifier and precision.
+          *
+          * FIXME: Add explicit location matching validation here. Be careful
+          * not to match varyings with explicit locations to varyings without
+          * explicit locations.
+          */
+         if ((in_var->data.explicit_location &&
+             out_var->data.explicit_location) &&
+             in_var->data.location == out_var->data.location &&
+             in_var->data.precision == out_var->data.precision)
+            continue;
+
+         unsigned len = strlen(in_var->name);
+
+         /* Handle input swizzle in variable name. */
+         const char *dot = strchr(in_var->name, '.');
+         if (dot)
+            len = dot - in_var->name;
+
+         /* Match by name and precision. */
+         if (strncmp(in_var->name, out_var->name, len) == 0) {
+            /* From OpenGL ES 3.1 spec:
+             *     "When both shaders are in separate programs, mismatched
+             *     precision qualifiers will result in a program interface
+             *     mismatch that will result in program pipeline validation
+             *     failures, as described in section 7.4.1 (“Shader Interface
+             *     Matching”) of the OpenGL ES 3.1 Specification."
+             */
+            if (in_var->data.precision != out_var->data.precision)
+               return false;
+         }
+      }
+   }
+   return inputs == outputs;
+}
+
+/**
+ * Validate inputs against outputs in a program pipeline.
+ */
+extern "C" bool
+_mesa_validate_pipeline_io(struct gl_pipeline_object *pipeline)
+{
+   struct gl_shader_program **shProg =
+      (struct gl_shader_program **) pipeline->CurrentProgram;
+
+   /* Find first active stage in pipeline. */
+   unsigned idx, prev = 0;
+   for (idx = 0; idx < ARRAY_SIZE(pipeline->CurrentProgram); idx++) {
+      if (shProg[idx]) {
+         prev = idx;
+         break;
+      }
+   }
+
+   for (idx = prev + 1; idx < ARRAY_SIZE(pipeline->CurrentProgram); idx++) {
+      if (shProg[idx]) {
+         /* Pipeline might include both non-compute and a compute program, do
+          * not attempt to validate varyings between non-compute and compute
+          * stage.
+          */
+         if (shProg[idx]->_LinkedShaders[idx]->Stage == MESA_SHADER_COMPUTE)
+            break;
+
+         if (!validate_io(shProg[prev]->_LinkedShaders[prev],
+                          shProg[idx]->_LinkedShaders[idx],
+                          shProg[prev]->IsES || shProg[idx]->IsES))
+            return false;
+         prev = idx;
+      }
+   }
+   return true;
+}