nir: Stop whacking gl_FrontFacing to a system value

We have a cap bit for gallium and a GLSL compiler flag to control this.
Just trust what GLSL gives us and stop forcing it.  In order for this to
be safe, we have to advertise another cap in some of the gallium
drivers.

Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: Eric Anholt <eric@anholt.net>

diff --git a/src/compiler/glsl/glsl_to_nir.cpp b/src/compiler/glsl/glsl_to_nir.cpp
index 7b454ca..3238c65 100644 (file)
--- a/src/compiler/glsl/glsl_to_nir.cpp
+++ b/src/compiler/glsl/glsl_to_nir.cpp
@@ -460,13 +460,8 @@ nir_visitor::visit(ir_variable *ir)
       break;
 
    case ir_var_shader_in:
-      if (shader->info.stage == MESA_SHADER_FRAGMENT &&
-          ir->data.location == VARYING_SLOT_FACE) {
-         /* For whatever reason, GLSL IR makes gl_FrontFacing an input */
-         var->data.location = SYSTEM_VALUE_FRONT_FACE;
-         var->data.mode = nir_var_system_value;
-      } else if (shader->info.stage == MESA_SHADER_GEOMETRY &&
-                 ir->data.location == VARYING_SLOT_PRIMITIVE_ID) {
+      if (shader->info.stage == MESA_SHADER_GEOMETRY &&
+          ir->data.location == VARYING_SLOT_PRIMITIVE_ID) {
          /* For whatever reason, GLSL IR makes gl_PrimitiveIDIn an input */
          var->data.location = SYSTEM_VALUE_PRIMITIVE_ID;
          var->data.mode = nir_var_system_value;

diff --git a/src/gallium/drivers/freedreno/freedreno_screen.c b/src/gallium/drivers/freedreno/freedreno_screen.c
index 4fbe6dd..2de02e3 100644 (file)
--- a/src/gallium/drivers/freedreno/freedreno_screen.c
+++ b/src/gallium/drivers/freedreno/freedreno_screen.c
@@ -365,6 +365,8 @@ fd_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
                if (is_ir3(screen))
                        return 1;
                return 0;
+       case PIPE_CAP_TGSI_FS_FACE_IS_INTEGER_SYSVAL:
+               return 1;
        case PIPE_CAP_MAX_STREAM_OUTPUT_SEPARATE_COMPONENTS:
        case PIPE_CAP_MAX_STREAM_OUTPUT_INTERLEAVED_COMPONENTS:
                if (is_ir3(screen))

diff --git a/src/gallium/drivers/v3d/v3d_screen.c b/src/gallium/drivers/v3d/v3d_screen.c
index 7fb63a4..083d2e9 100644 (file)
--- a/src/gallium/drivers/v3d/v3d_screen.c
+++ b/src/gallium/drivers/v3d/v3d_screen.c
@@ -136,6 +136,7 @@ v3d_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
         case PIPE_CAP_TGSI_PACK_HALF_FLOAT:
         case PIPE_CAP_TEXTURE_HALF_FLOAT_LINEAR:
         case PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT:
+        case PIPE_CAP_TGSI_FS_FACE_IS_INTEGER_SYSVAL:
                 return 1;
 
         case PIPE_CAP_PACKED_UNIFORMS:

diff --git a/src/gallium/drivers/vc4/vc4_screen.c b/src/gallium/drivers/vc4/vc4_screen.c
index d7325b8..4aeacc8 100644 (file)
--- a/src/gallium/drivers/vc4/vc4_screen.c
+++ b/src/gallium/drivers/vc4/vc4_screen.c
@@ -164,6 +164,7 @@ vc4_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
 
         case PIPE_CAP_TGSI_FS_COORD_ORIGIN_UPPER_LEFT:
         case PIPE_CAP_TGSI_FS_COORD_PIXEL_CENTER_HALF_INTEGER:
+        case PIPE_CAP_TGSI_FS_FACE_IS_INTEGER_SYSVAL:
                 return 1;
 
         case PIPE_CAP_MIXED_FRAMEBUFFER_SIZES:

diff --git a/src/mesa/drivers/dri/i965/brw_context.c b/src/mesa/drivers/dri/i965/brw_context.c
index 9105384..957be40 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_context.c
+++ b/src/mesa/drivers/dri/i965/brw_context.c
@@ -622,6 +622,7 @@ brw_initialize_context_constants(struct brw_context *brw)
       ctx->Const.MaxClipPlanes = 8;
 
    ctx->Const.GLSLFragCoordIsSysVal = true;
+   ctx->Const.GLSLFrontFacingIsSysVal = true;
    ctx->Const.GLSLTessLevelsAsInputs = true;
    ctx->Const.PrimitiveRestartForPatches = true;