From 7e6dac11866d264c21a108b9623114943d6e88ec Mon Sep 17 00:00:00 2001
From: =?utf8?q?Tapani=20P=C3=A4lli?= <tapani.palli@intel.com>
Date: Thu, 5 Nov 2015 12:52:26 +0200
Subject: [PATCH] mesa: validate precision of varyings during
 ValidateProgramPipeline
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Fixes following failing ES3.1 CTS tests:

   ES31-CTS.sepshaderobjs.InterfacePrecisionMatchingFloat
   ES31-CTS.sepshaderobjs.InterfacePrecisionMatchingInt
   ES31-CTS.sepshaderobjs.InterfacePrecisionMatchingUInt

Signed-off-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
---
 src/mesa/main/pipelineobj.c    | 15 ++++++++
 src/mesa/main/shader_query.cpp | 62 ++++++++++++++++++++++++++++++++++
 src/mesa/main/shaderobj.h      |  3 ++
 3 files changed, 80 insertions(+)

diff --git a/src/mesa/main/pipelineobj.c b/src/mesa/main/pipelineobj.c
index 699a2ae47eb..90dff13485b 100644
--- a/src/mesa/main/pipelineobj.c
+++ b/src/mesa/main/pipelineobj.c
@@ -907,6 +907,21 @@ _mesa_ValidateProgramPipeline(GLuint pipeline)
 
    _mesa_validate_program_pipeline(ctx, pipe,
                                    (ctx->_Shader->Name == pipe->Name));
+
+   /* Validate inputs against outputs, this cannot be done during linking
+    * since programs have been linked separately from each other.
+    *
+    * From OpenGL 4.5 Core spec:
+    *     "Separable program objects may have validation failures that cannot be
+    *     detected without the complete program pipeline. Mismatched interfaces,
+    *     improper usage of program objects together, and the same
+    *     state-dependent failures can result in validation errors for such
+    *     program objects."
+    *
+    * OpenGL ES 3.1 specification has the same text.
+    */
+   if (!_mesa_validate_pipeline_io(pipe))
+      pipe->Validated = GL_FALSE;
 }
 
 void GLAPIENTRY
diff --git a/src/mesa/main/shader_query.cpp b/src/mesa/main/shader_query.cpp
index 5cb877b0104..58ba04153e6 100644
--- a/src/mesa/main/shader_query.cpp
+++ b/src/mesa/main/shader_query.cpp
@@ -1359,3 +1359,65 @@ _mesa_get_program_resourceiv(struct gl_shader_program *shProg,
    if (length)
       *length = amount;
 }
+
+static bool
+validate_io(const struct gl_shader *input_stage,
+            const struct gl_shader *output_stage)
+{
+   assert(input_stage && output_stage);
+
+   /* For each output in a, find input in b and do any required checks. */
+   foreach_in_list(ir_instruction, out, input_stage->ir) {
+      ir_variable *out_var = out->as_variable();
+      if (!out_var || out_var->data.mode != ir_var_shader_out)
+         continue;
+
+      foreach_in_list(ir_instruction, in, output_stage->ir) {
+         ir_variable *in_var = in->as_variable();
+         if (!in_var || in_var->data.mode != ir_var_shader_in)
+            continue;
+
+         if (strcmp(in_var->name, out_var->name) == 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 true;
+}
+
+/**
+ * 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]) {
+         if (!validate_io(shProg[prev]->_LinkedShaders[prev],
+                          shProg[idx]->_LinkedShaders[idx]))
+            return false;
+         prev = idx;
+      }
+   }
+   return true;
+}
diff --git a/src/mesa/main/shaderobj.h b/src/mesa/main/shaderobj.h
index 796de470735..be80752d7f2 100644
--- a/src/mesa/main/shaderobj.h
+++ b/src/mesa/main/shaderobj.h
@@ -234,6 +234,9 @@ _mesa_shader_stage_to_subroutine_uniform(gl_shader_stage stage)
    }
 }
 
+extern bool
+_mesa_validate_pipeline_io(struct gl_pipeline_object *);
+
 #ifdef __cplusplus
 }
 #endif
-- 
2.30.2