vc4: Add support for reordering the uniform stream after optimization.

This allows for introducing dead code eliminating of uniforms, copy
propagation of uniforms, and instruction rescheduling between instructions
that both read uniforms.

4 files changed, 87 insertions, 0 deletions

diff --git a/src/gallium/drivers/vc4/Makefile.sources b/src/gallium/drivers/vc4/Makefile.sources
index bcb4209d0d0..71a28a5da20 100644
--- a/src/gallium/drivers/vc4/Makefile.sources
+++ b/src/gallium/drivers/vc4/Makefile.sources
@@ -24,6 +24,7 @@ C_SOURCES := \
 	vc4_qpu.h \
 	vc4_qpu_validate.c \
 	vc4_register_allocate.c \
+	vc4_reorder_uniforms.c \
 	vc4_resource.c \
 	vc4_resource.h \
 	vc4_screen.c \
diff --git a/src/gallium/drivers/vc4/vc4_program.c b/src/gallium/drivers/vc4/vc4_program.c
index 539fede50a1..c6603767b5e 100644
--- a/src/gallium/drivers/vc4/vc4_program.c
+++ b/src/gallium/drivers/vc4/vc4_program.c
@@ -1440,6 +1440,7 @@ vc4_shader_tgsi_to_qir(struct vc4_compiled_shader *shader, enum qstage stage,
                 fprintf(stderr, "QIR:\n");
                 qir_dump(c);
         }
+        qir_reorder_uniforms(c);
         vc4_generate_code(c);
 
         if (vc4_debug & VC4_DEBUG_SHADERDB) {
diff --git a/src/gallium/drivers/vc4/vc4_qir.h b/src/gallium/drivers/vc4/vc4_qir.h
index f3dad5ed67c..2ab30496aad 100644
--- a/src/gallium/drivers/vc4/vc4_qir.h
+++ b/src/gallium/drivers/vc4/vc4_qir.h
@@ -253,6 +253,7 @@ struct qinst *qir_inst4(enum qop op, struct qreg dst,
                         struct qreg c,
                         struct qreg d);
 void qir_remove_instruction(struct qinst *qinst);
+void qir_reorder_uniforms(struct vc4_compile *c);
 void qir_emit(struct vc4_compile *c, struct qinst *inst);
 struct qreg qir_get_temp(struct vc4_compile *c);
 int qir_get_op_nsrc(enum qop qop);
diff --git a/src/gallium/drivers/vc4/vc4_reorder_uniforms.c b/src/gallium/drivers/vc4/vc4_reorder_uniforms.c
new file mode 100644
index 00000000000..109724369d5
--- /dev/null
+++ b/src/gallium/drivers/vc4/vc4_reorder_uniforms.c
@@ -0,0 +1,84 @@
+/*
+ * Copyright © 2014 Broadcom
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+/**
+ * @file vc4_reorder_uniforms.c
+ *
+ * After optimization has occurred, rewrites the shader to have uniform reads
+ * reading from the c->uniform_contents[] in order, exactly once each.
+ *
+ * This allows optimization and instruction scheduling to move things around
+ * without worrying about how the hardware has the "each uniform read bumps
+ * the uniform read address" property.
+ */
+
+#include "util/ralloc.h"
+#include "util/u_math.h"
+#include "vc4_qir.h"
+
+void
+qir_reorder_uniforms(struct vc4_compile *c)
+{
+        uint32_t *uniform_index = NULL;
+        uint32_t uniform_index_size = 0;
+        uint32_t next_uniform = 0;
+        struct simple_node *node;
+        foreach(node, &c->instructions) {
+                struct qinst *inst = (struct qinst *)node;
+
+                for (int i = 0; i < qir_get_op_nsrc(inst->op); i++) {
+                        if (inst->src[i].file != QFILE_UNIF)
+                                continue;
+
+                        uint32_t new = next_uniform++;
+                        if (uniform_index_size <= new) {
+                                uniform_index_size =
+                                        MAX2(uniform_index_size * 2, 16);
+                                uniform_index =
+                                        realloc(uniform_index,
+                                                uniform_index_size *
+                                                sizeof(uint32_t));
+                        }
+
+                        uniform_index[new] = inst->src[i].index;
+                        inst->src[i].index = new;
+                }
+        }
+
+        uint32_t *uniform_data = ralloc_array(c, uint32_t, next_uniform);
+        enum quniform_contents *uniform_contents =
+                ralloc_array(c, enum quniform_contents, next_uniform);
+
+        for (uint32_t i = 0; i < next_uniform; i++) {
+                uniform_data[i] = c->uniform_data[uniform_index[i]];
+                uniform_contents[i] = c->uniform_contents[uniform_index[i]];
+        }
+
+        ralloc_free(c->uniform_data);
+        c->uniform_data = uniform_data;
+        ralloc_free(c->uniform_contents);
+        c->uniform_contents = uniform_contents;
+        c->num_uniforms = next_uniform;
+
+        free(uniform_index);
+}