shader: bump some snprintf limits to 512

This avois them overflowing when we have long swizzled gl_
which happens more with compute shaders and images

Reviewed-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Reviewed-by: Gert Wollny <gert.wollny@collabora.com>

src/vrend_shader.c

@@ -3118,7 +3118,7 @@ iter_instruction(struct tgsi_iterate_context *iter,
       EMIT_BUF_WITH_RET(ctx, buf);
       break;
    case TGSI_OPCODE_UADD:
-      snprintf(buf, 255, "%s = %s(%s(ivec4((uvec4(%s) + uvec4(%s))))%s);\n", dsts[0], get_string(dinfo.dstconv), get_string(dinfo.dtypeprefix), srcs[0], srcs[1], writemask);
+      snprintf(buf, 512, "%s = %s(%s(ivec4((uvec4(%s) + uvec4(%s))))%s);\n", dsts[0], get_string(dinfo.dstconv), get_string(dinfo.dtypeprefix), srcs[0], srcs[1], writemask);
       EMIT_BUF_WITH_RET(ctx, buf);
       break;
    case TGSI_OPCODE_SUB:
@@ -3136,7 +3136,7 @@ iter_instruction(struct tgsi_iterate_context *iter,
       EMIT_BUF_WITH_RET(ctx, buf);
       break;
    case TGSI_OPCODE_UMUL:
-      snprintf(buf, 255, "%s = %s(%s((uvec4(%s) * uvec4(%s)))%s);\n", dsts[0], get_string(dinfo.dstconv), get_string(dinfo.dtypeprefix), srcs[0], srcs[1], writemask);
+      snprintf(buf, 512, "%s = %s(%s((uvec4(%s) * uvec4(%s)))%s);\n", dsts[0], get_string(dinfo.dstconv), get_string(dinfo.dtypeprefix), srcs[0], srcs[1], writemask);
       EMIT_BUF_WITH_RET(ctx, buf);
       break;
    case TGSI_OPCODE_UMOD:
@@ -3166,7 +3166,7 @@ iter_instruction(struct tgsi_iterate_context *iter,
       break;
    case TGSI_OPCODE_UMAD:
    case TGSI_OPCODE_DMAD:
-      snprintf(buf, 255, "%s = %s(%s((%s * %s + %s)%s));\n", dsts[0], get_string(dinfo.dstconv), get_string(dinfo.dtypeprefix), srcs[0], srcs[1], srcs[2], writemask);
+      snprintf(buf, 512, "%s = %s(%s((%s * %s + %s)%s));\n", dsts[0], get_string(dinfo.dstconv), get_string(dinfo.dtypeprefix), srcs[0], srcs[1], srcs[2], writemask);
       EMIT_BUF_WITH_RET(ctx, buf);
       break;
    case TGSI_OPCODE_OR: