1 files changed, 174 insertions, 0 deletions
diff --git a/src/compiler/nir/nir_sweep.c b/src/compiler/nir/nir_sweep.c
new file mode 100644
index 00000000000..5c62154ec7f
--- /dev/null
+++ b/src/compiler/nir/nir_sweep.c
@@ -0,0 +1,174 @@
+/*
+ * Copyright © 2015 Intel Corporation
+ *
+ * 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.
+ */
+
+#include "nir.h"
+
+/**
+ * \file nir_sweep.c
+ *
+ * The nir_sweep() pass performs a mark and sweep pass over a nir_shader's associated
+ * memory - anything still connected to the program will be kept, and any dead memory
+ * we dropped on the floor will be freed.
+ *
+ * The expectation is that drivers should call this when finished compiling the shader
+ * (after any optimization, lowering, and so on).  However, it's also fine to call it
+ * earlier, and even many times, trading CPU cycles for memory savings.
+ */
+
+#define steal_list(mem_ctx, type, list) \
+   foreach_list_typed(type, obj, node, list) { ralloc_steal(mem_ctx, obj); }
+
+static void sweep_cf_node(nir_shader *nir, nir_cf_node *cf_node);
+
+static bool
+sweep_src_indirect(nir_src *src, void *nir)
+{
+   if (!src->is_ssa && src->reg.indirect)
+      ralloc_steal(nir, src->reg.indirect);
+
+   return true;
+}
+
+static bool
+sweep_dest_indirect(nir_dest *dest, void *nir)
+{
+   if (!dest->is_ssa && dest->reg.indirect)
+      ralloc_steal(nir, dest->reg.indirect);
+
+   return true;
+}
+
+static void
+sweep_block(nir_shader *nir, nir_block *block)
+{
+   ralloc_steal(nir, block);
+
+   nir_foreach_instr(block, instr) {
+      ralloc_steal(nir, instr);
+
+      nir_foreach_src(instr, sweep_src_indirect, nir);
+      nir_foreach_dest(instr, sweep_dest_indirect, nir);
+   }
+}
+
+static void
+sweep_if(nir_shader *nir, nir_if *iff)
+{
+   ralloc_steal(nir, iff);
+
+   foreach_list_typed(nir_cf_node, cf_node, node, &iff->then_list) {
+      sweep_cf_node(nir, cf_node);
+   }
+
+   foreach_list_typed(nir_cf_node, cf_node, node, &iff->else_list) {
+      sweep_cf_node(nir, cf_node);
+   }
+}
+
+static void
+sweep_loop(nir_shader *nir, nir_loop *loop)
+{
+   ralloc_steal(nir, loop);
+
+   foreach_list_typed(nir_cf_node, cf_node, node, &loop->body) {
+      sweep_cf_node(nir, cf_node);
+   }
+}
+
+static void
+sweep_cf_node(nir_shader *nir, nir_cf_node *cf_node)
+{
+   switch (cf_node->type) {
+   case nir_cf_node_block:
+      sweep_block(nir, nir_cf_node_as_block(cf_node));
+      break;
+   case nir_cf_node_if:
+      sweep_if(nir, nir_cf_node_as_if(cf_node));
+      break;
+   case nir_cf_node_loop:
+      sweep_loop(nir, nir_cf_node_as_loop(cf_node));
+      break;
+   default:
+      unreachable("Invalid CF node type");
+   }
+}
+
+static void
+sweep_impl(nir_shader *nir, nir_function_impl *impl)
+{
+   ralloc_steal(nir, impl);
+
+   ralloc_steal(nir, impl->params);
+   ralloc_steal(nir, impl->return_var);
+   steal_list(nir, nir_variable, &impl->locals);
+   steal_list(nir, nir_register, &impl->registers);
+
+   foreach_list_typed(nir_cf_node, cf_node, node, &impl->body) {
+      sweep_cf_node(nir, cf_node);
+   }
+
+   sweep_block(nir, impl->end_block);
+
+   /* Wipe out all the metadata, if any. */
+   nir_metadata_preserve(impl, nir_metadata_none);
+}
+
+static void
+sweep_function(nir_shader *nir, nir_function *f)
+{
+   ralloc_steal(nir, f);
+   ralloc_steal(nir, f->params);
+
+   if (f->impl)
+      sweep_impl(nir, f->impl);
+}
+
+void
+nir_sweep(nir_shader *nir)
+{
+   void *rubbish = ralloc_context(NULL);
+
+   /* First, move ownership of all the memory to a temporary context; assume dead. */
+   ralloc_adopt(rubbish, nir);
+
+   ralloc_steal(nir, (char *)nir->info.name);
+   if (nir->info.label)
+      ralloc_steal(nir, (char *)nir->info.label);
+
+   /* Variables and registers are not dead.  Steal them back. */
+   steal_list(nir, nir_variable, &nir->uniforms);
+   steal_list(nir, nir_variable, &nir->inputs);
+   steal_list(nir, nir_variable, &nir->outputs);
+   steal_list(nir, nir_variable, &nir->shared);
+   steal_list(nir, nir_variable, &nir->globals);
+   steal_list(nir, nir_variable, &nir->system_values);
+   steal_list(nir, nir_register, &nir->registers);
+
+   /* Recurse into functions, stealing their contents back. */
+   foreach_list_typed(nir_function, func, node, &nir->functions) {
+      sweep_function(nir, func);
+   }
+
+   /* Free everything we didn't steal back. */
+   ralloc_free(rubbish);
+}