freedreno/a3xx: fix const confusion

Gallium can leave const buffers bound above what is used by the current
shader.  Which can have a couple bad effects:

1) write beyond const space assigned, which can trigger HLSQ lockup
2) double emit of immed consts, first with bound const buffer vals
followed by with actual immed vals.  This seems to be a sort of
undefined condition.

Signed-off-by: Rob Clark <robclark@freedesktop.org>

src/gallium/drivers/freedreno/a3xx/fd3_compiler.c

@@ -157,7 +157,7 @@ compile_init(struct fd3_compile_context *ctx, struct fd3_shader_stateobj *so,
 			info->file_max[TGSI_FILE_OUTPUT] + 1;
 
 	so->first_immediate = ctx->base_reg[TGSI_FILE_IMMEDIATE];
-	ctx->immediate_idx = 4 * (info->file_max[TGSI_FILE_IMMEDIATE] + 1);
+	ctx->immediate_idx = 4 * (ctx->info.file_max[TGSI_FILE_IMMEDIATE] + 1);
 
 	ret = tgsi_parse_init(&ctx->parser, tokens);
 	if (ret != TGSI_PARSE_OK)

src/gallium/drivers/freedreno/a3xx/fd3_emit.c

@@ -115,12 +115,10 @@ emit_constants(struct fd_ringbuffer *ring,
 		// I expect that size should be a multiple of vec4's:
 		assert(size == align(size, 4));
 
-		/* gallium could have const-buffer still bound, even though the
-		 * shader is not using it.  Writing consts above constlen (or
-		 * rather, HLSQ_{VS,FS}_CONTROL_REG.CONSTLENGTH) will cause a
-		 * hang.
+		/* gallium could leave const buffers bound above what the
+		 * current shader uses.. don't let that confuse us.
 		 */
-		if ((base / 4) >= shader->constlen)
+		if (base >= (4 * shader->first_immediate))
 			break;
 
 		if (constbuf->dirty_mask & (1 << index)) {
@@ -137,9 +135,11 @@ emit_constants(struct fd_ringbuffer *ring,
 	/* emit shader immediates: */
 	if (shader) {
 		for (i = 0; i < shader->immediates_count; i++) {
-			fd3_emit_constant(ring, sb,
-					4 * (shader->first_immediate + i),
-					0, 4, shader->immediates[i].val, NULL);
+			base = 4 * (shader->first_immediate + i);
+			if (base >= (4 * shader->constlen))
+				break;
+			fd3_emit_constant(ring, sb, base,
+				0, 4, shader->immediates[i].val, NULL);
 		}
 	}
 }