mesa: bump MAX_VARYING to 32

We're starting to get apps utilizing more than 16 varyings and
most current hardware supports 32 anyway.

Tested with r600g.
swrast, softpipe and llvmpipe still advertise 16 varyings.

This fixes a WebGL crash after launching this demo:
https://developer.mozilla.org/en-US/demos/detail/falling-cubes

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=54402

NOTE: This is a candidate for the stable branches.

Acked-by: Kenneth Graunke <kenneth@whitecape.org>

src/gallium/auxiliary/tgsi/tgsi_ureg.c

@@ -73,7 +73,7 @@ struct ureg_tokens {
 
 #define UREG_MAX_INPUT PIPE_MAX_ATTRIBS
 #define UREG_MAX_SYSTEM_VALUE PIPE_MAX_ATTRIBS
-#define UREG_MAX_OUTPUT PIPE_MAX_ATTRIBS
+#define UREG_MAX_OUTPUT PIPE_MAX_SHADER_OUTPUTS
 #define UREG_MAX_CONSTANT_RANGE 32
 #define UREG_MAX_IMMEDIATE 256
 #define UREG_MAX_ADDR 2

src/gallium/include/pipe/p_state.h

@@ -59,7 +59,7 @@ extern "C" {
 #define PIPE_MAX_CONSTANT_BUFFERS 32
 #define PIPE_MAX_SAMPLERS         16
 #define PIPE_MAX_SHADER_INPUTS    32
-#define PIPE_MAX_SHADER_OUTPUTS   32
+#define PIPE_MAX_SHADER_OUTPUTS   48 /* 32 GENERICs + POS, PSIZE, FOG, etc. */
 #define PIPE_MAX_SHADER_SAMPLER_VIEWS 32
 #define PIPE_MAX_SHADER_RESOURCES 32
 #define PIPE_MAX_TEXTURE_LEVELS   16
@@ -145,7 +145,7 @@ struct pipe_rasterizer_state
    unsigned line_stipple_factor:8;  /**< [1..256] actually */
    unsigned line_stipple_pattern:16;
 
-   unsigned sprite_coord_enable:PIPE_MAX_SHADER_OUTPUTS;
+   unsigned sprite_coord_enable; /* bitfield referring to 32 GENERIC inputs */
 
    float line_width;
    float point_size;           /**< used when no per-vertex size */

src/mesa/main/config.h

@@ -187,7 +187,7 @@
 #define MAX_PROGRAM_CALL_DEPTH         8
 #define MAX_PROGRAM_TEMPS              256
 #define MAX_PROGRAM_ADDRESS_REGS       2
-#define MAX_VARYING                    16    /**< number of float[4] vectors */
+#define MAX_VARYING                    32    /**< number of float[4] vectors */
 #define MAX_SAMPLERS                   MAX_TEXTURE_IMAGE_UNITS
 #define MAX_PROGRAM_INPUTS             32
 #define MAX_PROGRAM_OUTPUTS            64

src/mesa/main/context.c

@@ -614,7 +614,7 @@ _mesa_init_constants(struct gl_context *ctx)
 
    ctx->Const.MaxVertexTextureImageUnits = MAX_VERTEX_TEXTURE_IMAGE_UNITS;
    ctx->Const.MaxCombinedTextureImageUnits = MAX_COMBINED_TEXTURE_IMAGE_UNITS;
-   ctx->Const.MaxVarying = MAX_VARYING;
+   ctx->Const.MaxVarying = 16; /* old limit not to break tnl and swrast */
    ctx->Const.MaxGeometryTextureImageUnits = MAX_GEOMETRY_TEXTURE_IMAGE_UNITS;
    ctx->Const.MaxVertexVaryingComponents = MAX_VERTEX_VARYING_COMPONENTS;
    ctx->Const.MaxGeometryVaryingComponents = MAX_GEOMETRY_VARYING_COMPONENTS;

src/mesa/program/prog_print.c

@@ -158,7 +158,23 @@ arb_input_attrib_string(GLint index, GLenum progType)
       "fragment.varying[12]",
       "fragment.varying[13]",
       "fragment.varying[14]",
-      "fragment.varying[15]" /* MAX_VARYING = 16 */
+      "fragment.varying[15]",
+      "fragment.varying[16]",
+      "fragment.varying[17]",
+      "fragment.varying[18]",
+      "fragment.varying[19]",
+      "fragment.varying[20]",
+      "fragment.varying[21]",
+      "fragment.varying[22]",
+      "fragment.varying[23]",
+      "fragment.varying[24]",
+      "fragment.varying[25]",
+      "fragment.varying[26]",
+      "fragment.varying[27]",
+      "fragment.varying[28]",
+      "fragment.varying[29]",
+      "fragment.varying[30]",
+      "fragment.varying[31]", /* MAX_VARYING = 32 */
    };
 
    /* sanity checks */
@@ -262,7 +278,23 @@ arb_output_attrib_string(GLint index, GLenum progType)
       "result.varying[12]",
       "result.varying[13]",
       "result.varying[14]",
-      "result.varying[15]" /* MAX_VARYING = 16 */
+      "result.varying[15]",
+      "result.varying[16]",
+      "result.varying[17]",
+      "result.varying[18]",
+      "result.varying[19]",
+      "result.varying[20]",
+      "result.varying[21]",
+      "result.varying[22]",
+      "result.varying[23]",
+      "result.varying[24]",
+      "result.varying[25]",
+      "result.varying[26]",
+      "result.varying[27]",
+      "result.varying[28]",
+      "result.varying[29]",
+      "result.varying[30]",
+      "result.varying[31]", /* MAX_VARYING = 32 */
    };
    static const char *const fragResults[] = {
       "result.depth", /* FRAG_RESULT_DEPTH */