nir: add a validation pass

This is similar to ir_validate.cpp.

v2: Jason Ekstrand <[email protected]>:
   whitespace fixes

3 files changed, 793 insertions, 0 deletions

diff --git a/src/glsl/Makefile.sources b/src/glsl/Makefile.sources
index fa03b2a7e4a..1b7e1594c69 100644
--- a/src/glsl/Makefile.sources
+++ b/src/glsl/Makefile.sources
@@ -21,6 +21,7 @@ NIR_FILES = \
 	$(GLSL_SRCDIR)/nir/nir_opcodes.c \
 	$(GLSL_SRCDIR)/nir/nir_opcodes.h \
 	$(GLSL_SRCDIR)/nir/nir_print.c \
+	$(GLSL_SRCDIR)/nir/nir_validate.c \
 	$(GLSL_SRCDIR)/nir/nir_types.cpp
 
 # libglsl
diff --git a/src/glsl/nir/nir.h b/src/glsl/nir/nir.h
index 4b1f162964f..00f5f489cb7 100644
--- a/src/glsl/nir/nir.h
+++ b/src/glsl/nir/nir.h
@@ -1240,6 +1240,8 @@ void nir_index_blocks(nir_function_impl *impl);
 
 void nir_print_shader(nir_shader *shader, FILE *fp);
 
+void nir_validate_shader(nir_shader *shader);
+
 #ifdef __cplusplus
 } /* extern "C" */
 #endif
diff --git a/src/glsl/nir/nir_validate.c b/src/glsl/nir/nir_validate.c
new file mode 100644
index 00000000000..1d8452d6920
--- /dev/null
+++ b/src/glsl/nir/nir_validate.c
@@ -0,0 +1,790 @@
+/*
+ * Copyright © 2014 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.
+ *
+ * Authors:
+ *    Connor Abbott ([email protected])
+ *
+ */
+
+#include "nir.h"
+#include <assert.h>
+
+/*
+ * This file checks for invalid IR indicating a bug somewhere in the compiler.
+ */
+
+/*
+ * Per-register validation state.
+ */
+
+typedef struct {
+   /*
+    * equivalent to the uses and defs in nir_register, but built up by the
+    * validator. At the end, we verify that the sets have the same entries.
+    */
+   struct set *uses, *defs;
+   nir_function_impl *where_defined; /* NULL for global registers */
+} reg_validate_state;
+
+typedef struct {
+   /* map of register -> validation state (struct above) */
+   struct hash_table *regs;
+
+   /* the current instruction being validated */
+   nir_instr *instr;
+
+   /* the current basic block being validated */
+   nir_block *block;
+
+   /* the current if statement being validated */
+   nir_if *if_stmt;
+
+   /* the parent of the current cf node being visited */
+   nir_cf_node *parent_node;
+
+   /* the current function implementation being validated */
+   nir_function_impl *impl;
+
+   /* map of SSA value -> function implementation where it is defined */
+   struct hash_table *ssa_defs;
+
+   /* map of local variable -> function implementation where it is defined */
+   struct hash_table *var_defs;
+} validate_state;
+
+static void validate_src(nir_src *src, validate_state *state);
+
+static void
+validate_reg_src(nir_reg_src *src, validate_state *state)
+{
+   assert(src->reg != NULL);
+
+   struct set_entry *entry =
+      _mesa_set_search(src->reg->uses, _mesa_hash_pointer(state->instr),
+                       state->instr);
+   assert(entry && "use not in nir_register.uses");
+
+   struct hash_entry *entry2;
+   entry2 = _mesa_hash_table_search(state->regs, src->reg);
+
+   assert(entry2);
+
+   reg_validate_state *reg_state = (reg_validate_state *) entry2->data;
+   _mesa_set_add(reg_state->uses, _mesa_hash_pointer(state->instr),
+                 state->instr);
+
+   if (!src->reg->is_global) {
+      assert(reg_state->where_defined == state->impl &&
+             "using a register declared in a different function");
+   }
+
+   assert((src->reg->num_array_elems == 0 ||
+          src->base_offset < src->reg->num_array_elems) &&
+          "definitely out-of-bounds array access");
+
+   if (src->indirect) {
+      assert(src->reg->num_array_elems != 0);
+      assert((src->indirect->is_ssa || src->indirect->reg.indirect == NULL) &&
+             "only one level of indirection allowed");
+      validate_src(src->indirect, state);
+   }
+}
+
+static void
+validate_ssa_src(nir_ssa_def *def, validate_state *state)
+{
+   assert(def != NULL);
+
+   struct hash_entry *entry = _mesa_hash_table_search(state->ssa_defs, def);
+
+   assert(entry);
+
+   assert((nir_function_impl *) entry->data == state->impl &&
+          "using an SSA value defined in a different function");
+
+   struct set_entry *entry2;
+
+   entry2 = _mesa_set_search(def->uses, _mesa_hash_pointer(state->instr),
+                              state->instr);
+
+   assert(entry2 && "SSA use missing");
+
+   /* TODO validate that the use is dominated by the definition */
+}
+
+static void
+validate_src(nir_src *src, validate_state *state)
+{
+   if (src->is_ssa)
+      validate_ssa_src(src->ssa, state);
+   else
+      validate_reg_src(&src->reg, state);
+}
+
+static void
+validate_alu_src(nir_alu_instr *instr, unsigned index, validate_state *state)
+{
+   nir_alu_src *src = &instr->src[index];
+
+   unsigned num_components;
+   if (src->src.is_ssa)
+      num_components = src->src.ssa->num_components;
+   else {
+      if (src->src.reg.reg->is_packed)
+         num_components = 4; /* can't check anything */
+      else
+         num_components = src->src.reg.reg->num_components;
+   }
+   for (unsigned i = 0; i < 4; i++) {
+      assert(src->swizzle[i] < 4);
+
+      if (nir_alu_instr_channel_used(instr, index, i))
+         assert(src->swizzle[i] < num_components);
+   }
+
+   validate_src(&src->src, state);
+}
+
+static void
+validate_reg_dest(nir_reg_dest *dest, validate_state *state)
+{
+   assert(dest->reg != NULL);
+
+   struct set_entry *entry =
+      _mesa_set_search(dest->reg->defs, _mesa_hash_pointer(state->instr),
+                       state->instr);
+   assert(entry && "definition not in nir_register.defs");
+
+   struct hash_entry *entry2;
+   entry2 = _mesa_hash_table_search(state->regs, dest->reg);
+
+   assert(entry2);
+
+   reg_validate_state *reg_state = (reg_validate_state *) entry2->data;
+   _mesa_set_add(reg_state->defs, _mesa_hash_pointer(state->instr),
+                 state->instr);
+
+   if (!dest->reg->is_global) {
+      assert(reg_state->where_defined == state->impl &&
+             "writing to a register declared in a different function");
+   }
+
+   assert((dest->reg->num_array_elems == 0 ||
+          dest->base_offset < dest->reg->num_array_elems) &&
+          "definitely out-of-bounds array access");
+
+   if (dest->indirect) {
+      assert(dest->reg->num_array_elems != 0);
+      assert((dest->indirect->is_ssa || dest->indirect->reg.indirect == NULL) &&
+             "only one level of indirection allowed");
+      validate_src(dest->indirect, state);
+   }
+}
+
+static void
+validate_ssa_def(nir_ssa_def *def, validate_state *state)
+{
+   assert(def->num_components <= 4);
+   _mesa_hash_table_insert(state->ssa_defs, def, state->impl);
+}
+
+static void
+validate_dest(nir_dest *dest, validate_state *state)
+{
+   if (dest->is_ssa)
+      validate_ssa_def(&dest->ssa, state);
+   else
+      validate_reg_dest(&dest->reg, state);
+}
+
+static void
+validate_alu_dest(nir_alu_dest *dest, validate_state *state)
+{
+   unsigned dest_size =
+      dest->dest.is_ssa ? dest->dest.ssa.num_components
+                        : dest->dest.reg.reg->num_components;
+   bool is_packed = !dest->dest.is_ssa && dest->dest.reg.reg->is_packed;
+   /*
+    * validate that the instruction doesn't write to components not in the
+    * register/SSA value
+    */
+   assert(is_packed || !(dest->write_mask & ~((1 << dest_size) - 1)));
+   validate_dest(&dest->dest, state);
+}
+
+static void
+validate_alu_instr(nir_alu_instr *instr, validate_state *state)
+{
+   assert(instr->op < nir_num_opcodes);
+
+   validate_alu_dest(&instr->dest, state);
+
+   for (unsigned i = 0; i < nir_op_infos[instr->op].num_inputs; i++) {
+      validate_alu_src(instr, i, state);
+   }
+
+   if (instr->has_predicate)
+      validate_src(&instr->predicate, state);
+}
+
+static void
+validate_deref_chain(nir_deref *deref, validate_state *state)
+{
+   nir_deref *parent = NULL;
+   while (deref != NULL) {
+      switch (deref->deref_type) {
+      case nir_deref_type_array:
+         assert(deref->type == glsl_get_array_element(parent->type));
+         if (nir_deref_as_array(deref)->has_indirect)
+            validate_src(&nir_deref_as_array(deref)->indirect, state);
+         break;
+
+      case nir_deref_type_struct:
+         assert(deref->type ==
+                glsl_get_struct_field(parent->type,
+                                      nir_deref_as_struct(deref)->elem));
+         break;
+
+      case nir_deref_type_var:
+         break;
+
+      default:
+         assert(!"Invalid deref type");
+         break;
+      }
+
+      parent = deref;
+      deref = deref->child;
+   }
+}
+
+static void
+validate_var_use(nir_variable *var, validate_state *state)
+{
+   if (var->data.mode == nir_var_local) {
+      struct hash_entry *entry = _mesa_hash_table_search(state->var_defs, var);
+
+      assert(entry);
+      assert((nir_function_impl *) entry->data == state->impl);
+   }
+}
+
+static void
+validate_deref_var(nir_deref_var *deref, validate_state *state)
+{
+   assert(deref != NULL);
+   assert(deref->deref.type == deref->var->type);
+
+   validate_var_use(deref->var, state);
+
+   validate_deref_chain(&deref->deref, state);
+}
+
+static void
+validate_intrinsic_instr(nir_intrinsic_instr *instr, validate_state *state)
+{
+   unsigned num_srcs = nir_intrinsic_infos[instr->intrinsic].num_srcs;
+   for (unsigned i = 0; i < num_srcs; i++) {
+      validate_src(&instr->src[i], state);
+   }
+
+   if (nir_intrinsic_infos[instr->intrinsic].has_dest) {
+      validate_dest(&instr->dest, state);
+   }
+
+   unsigned num_vars = nir_intrinsic_infos[instr->intrinsic].num_variables;
+   for (unsigned i = 0; i < num_vars; i++) {
+      validate_deref_var(instr->variables[i], state);
+   }
+
+   if (instr->has_predicate)
+      validate_src(&instr->predicate, state);
+}
+
+static void
+validate_tex_instr(nir_tex_instr *instr, validate_state *state)
+{
+   validate_dest(&instr->dest, state);
+
+   bool src_type_seen[nir_num_texinput_types];
+   for (unsigned i = 0; i < nir_num_texinput_types; i++)
+      src_type_seen[i] = false;
+
+   for (unsigned i = 0; i < instr->num_srcs; i++) {
+      assert(!src_type_seen[instr->src_type[i]]);
+      src_type_seen[instr->src_type[i]] = true;
+      validate_src(&instr->src[i], state);
+   }
+
+   if (instr->sampler != NULL)
+      validate_deref_var(instr->sampler, state);
+}
+
+static void
+validate_call_instr(nir_call_instr *instr, validate_state *state)
+{
+   if (instr->return_deref == NULL)
+      assert(glsl_type_is_void(instr->callee->return_type));
+   else
+      assert(instr->return_deref->deref.type == instr->callee->return_type);
+
+   assert(instr->num_params == instr->callee->num_params);
+
+   for (unsigned i = 0; i < instr->num_params; i++) {
+      assert(instr->callee->params[i].type == instr->params[i]->deref.type);
+      validate_deref_var(instr->params[i], state);
+   }
+
+   validate_deref_var(instr->return_deref, state);
+
+   if (instr->has_predicate)
+      validate_src(&instr->predicate, state);
+}
+
+static void
+validate_load_const_instr(nir_load_const_instr *instr, validate_state *state)
+{
+   validate_dest(&instr->dest, state);
+
+   if (instr->array_elems != 0) {
+      assert(!instr->dest.is_ssa);
+      assert(instr->dest.reg.base_offset + instr->array_elems <=
+             instr->dest.reg.reg->num_array_elems);
+   }
+
+   if (instr->has_predicate)
+      validate_src(&instr->predicate, state);
+}
+
+static void
+validate_ssa_undef_instr(nir_ssa_undef_instr *instr, validate_state *state)
+{
+   validate_ssa_def(&instr->def, state);
+}
+
+static void
+validate_phi_instr(nir_phi_instr *instr, validate_state *state)
+{
+   /*
+    * don't validate the sources until we get to them from their predecessor
+    * basic blocks, to avoid validating an SSA use before its definition.
+    */
+
+   validate_dest(&instr->dest, state);
+
+   assert(exec_list_length(&instr->srcs) ==
+          state->block->predecessors->entries);
+}
+
+static void
+validate_instr(nir_instr *instr, validate_state *state)
+{
+   assert(instr->block == state->block);
+
+   state->instr = instr;
+
+   switch (instr->type) {
+   case nir_instr_type_alu:
+      validate_alu_instr(nir_instr_as_alu(instr), state);
+      break;
+
+   case nir_instr_type_call:
+      validate_call_instr(nir_instr_as_call(instr), state);
+      break;
+
+   case nir_instr_type_intrinsic:
+      validate_intrinsic_instr(nir_instr_as_intrinsic(instr), state);
+      break;
+
+   case nir_instr_type_texture:
+      validate_tex_instr(nir_instr_as_texture(instr), state);
+      break;
+
+   case nir_instr_type_load_const:
+      validate_load_const_instr(nir_instr_as_load_const(instr), state);
+      break;
+
+   case nir_instr_type_phi:
+      validate_phi_instr(nir_instr_as_phi(instr), state);
+      break;
+
+   case nir_instr_type_ssa_undef:
+      validate_ssa_undef_instr(nir_instr_as_ssa_undef(instr), state);
+      break;
+
+   case nir_instr_type_jump:
+      break;
+
+   default:
+      assert(!"Invalid ALU instruction type");
+      break;
+   }
+}
+
+static void
+validate_phi_src(nir_phi_instr *instr, nir_block *pred, validate_state *state)
+{
+   state->instr = &instr->instr;
+
+   foreach_list_typed(nir_phi_src, src, node, &instr->srcs) {
+      if (src->pred == pred) {
+         validate_src(&src->src, state);
+         return;
+      }
+   }
+
+   abort();
+}
+
+static void
+validate_phi_srcs(nir_block *block, nir_block *succ, validate_state *state)
+{
+   nir_foreach_instr(succ, instr) {
+      if (instr->type != nir_instr_type_phi)
+         break;
+
+      validate_phi_src(nir_instr_as_phi(instr), block, state);
+   }
+}
+
+static void validate_cf_node(nir_cf_node *node, validate_state *state);
+
+static void
+validate_block(nir_block *block, validate_state *state)
+{
+   assert(block->cf_node.parent == state->parent_node);
+
+   state->block = block;
+
+   nir_foreach_instr(block, instr) {
+      if (instr->type == nir_instr_type_phi) {
+         assert(instr == nir_block_first_instr(block) ||
+                nir_instr_prev(instr)->type == nir_instr_type_phi);
+      }
+
+      if (instr->type == nir_instr_type_jump) {
+         assert(instr == nir_block_last_instr(block));
+      }
+
+      validate_instr(instr, state);
+   }
+
+   assert(block->successors[0] != NULL);
+
+   for (unsigned i = 0; i < 2; i++) {
+      if (block->successors[i] != NULL) {
+         struct set_entry *entry =
+            _mesa_set_search(block->successors[i]->predecessors,
+                             _mesa_hash_pointer(block), block);
+         assert(entry);
+
+         validate_phi_srcs(block, block->successors[i], state);
+      }
+   }
+
+   if (!exec_list_is_empty(&block->instr_list) &&
+       nir_block_last_instr(block)->type == nir_instr_type_jump)
+      assert(block->successors[1] == NULL);
+}
+
+static void
+validate_if(nir_if *if_stmt, validate_state *state)
+{
+   assert(!exec_node_is_head_sentinel(if_stmt->cf_node.node.prev));
+   nir_cf_node *prev_node = nir_cf_node_prev(&if_stmt->cf_node);
+   assert(prev_node->type == nir_cf_node_block);
+
+   nir_block *prev_block = nir_cf_node_as_block(prev_node);
+   assert(&prev_block->successors[0]->cf_node ==
+          nir_if_first_then_node(if_stmt));
+   assert(&prev_block->successors[1]->cf_node ==
+          nir_if_first_else_node(if_stmt));
+
+   assert(!exec_node_is_tail_sentinel(if_stmt->cf_node.node.next));
+   nir_cf_node *next_node = nir_cf_node_next(&if_stmt->cf_node);
+   assert(next_node->type == nir_cf_node_block);
+
+   if (!if_stmt->condition.is_ssa) {
+      nir_register *reg = if_stmt->condition.reg.reg;
+      struct set_entry *entry =
+         _mesa_set_search(reg->if_uses, _mesa_hash_pointer(if_stmt), if_stmt);
+      assert(entry);
+   } else {
+      nir_ssa_def *def = if_stmt->condition.ssa;
+      struct set_entry *entry =
+         _mesa_set_search(def->if_uses, _mesa_hash_pointer(if_stmt), if_stmt);
+      assert(entry);
+   }
+
+   assert(!exec_list_is_empty(&if_stmt->then_list));
+   assert(!exec_list_is_empty(&if_stmt->else_list));
+
+   nir_cf_node *old_parent = state->parent_node;
+   state->parent_node = &if_stmt->cf_node;
+
+   foreach_list_typed(nir_cf_node, cf_node, node, &if_stmt->then_list) {
+      validate_cf_node(cf_node, state);
+   }
+
+   foreach_list_typed(nir_cf_node, cf_node, node, &if_stmt->else_list) {
+      validate_cf_node(cf_node, state);
+   }
+
+   state->parent_node = old_parent;
+}
+
+static void
+validate_loop(nir_loop *loop, validate_state *state)
+{
+   assert(!exec_node_is_head_sentinel(loop->cf_node.node.prev));
+   nir_cf_node *prev_node = nir_cf_node_prev(&loop->cf_node);
+   assert(prev_node->type == nir_cf_node_block);
+
+   nir_block *prev_block = nir_cf_node_as_block(prev_node);
+   assert(&prev_block->successors[0]->cf_node == nir_loop_first_cf_node(loop));
+   assert(prev_block->successors[1] == NULL);
+
+   assert(!exec_node_is_tail_sentinel(loop->cf_node.node.next));
+   nir_cf_node *next_node = nir_cf_node_next(&loop->cf_node);
+   assert(next_node->type == nir_cf_node_block);
+
+   assert(!exec_list_is_empty(&loop->body));
+
+   nir_cf_node *old_parent = state->parent_node;
+   state->parent_node = &loop->cf_node;
+
+   foreach_list_typed(nir_cf_node, cf_node, node, &loop->body) {
+      validate_cf_node(cf_node, state);
+   }
+
+   state->parent_node = old_parent;
+}
+
+static void
+validate_cf_node(nir_cf_node *node, validate_state *state)
+{
+   assert(node->parent == state->parent_node);
+
+   switch (node->type) {
+   case nir_cf_node_block:
+      validate_block(nir_cf_node_as_block(node), state);
+      break;
+
+   case nir_cf_node_if:
+      validate_if(nir_cf_node_as_if(node), state);
+      break;
+
+   case nir_cf_node_loop:
+      validate_loop(nir_cf_node_as_loop(node), state);
+      break;
+
+   default:
+      assert(!"Invalid ALU instruction type");
+      break;
+   }
+}
+
+static void
+prevalidate_reg_decl(nir_register *reg, bool is_global, validate_state *state)
+{
+   assert(reg->is_global == is_global);
+
+   reg_validate_state *reg_state = ralloc(state->regs, reg_validate_state);
+   reg_state->uses = _mesa_set_create(reg_state, _mesa_key_pointer_equal);
+   reg_state->defs = _mesa_set_create(reg_state, _mesa_key_pointer_equal);
+
+   reg_state->where_defined = is_global ? NULL : state->impl;
+
+   _mesa_hash_table_insert(state->regs, reg, reg_state);
+}
+
+static void
+postvalidate_reg_decl(nir_register *reg, validate_state *state)
+{
+   struct hash_entry *entry = _mesa_hash_table_search(state->regs, reg);
+
+   reg_validate_state *reg_state = (reg_validate_state *) entry->data;
+
+   if (reg_state->uses->entries != reg->uses->entries) {
+      printf("extra entries in register uses:\n");
+      struct set_entry *entry;
+      set_foreach(reg->uses, entry) {
+         struct set_entry *entry2 =
+            _mesa_set_search(reg_state->uses, _mesa_hash_pointer(entry->key),
+                             entry->key);
+
+         if (entry2 == NULL) {
+            printf("%p\n", entry->key);
+         }
+      }
+
+      abort();
+   }
+
+   if (reg_state->defs->entries != reg->defs->entries) {
+      printf("extra entries in register defs:\n");
+      struct set_entry *entry;
+      set_foreach(reg->defs, entry) {
+         struct set_entry *entry2 =
+            _mesa_set_search(reg_state->defs, _mesa_hash_pointer(entry->key),
+                             entry->key);
+
+         if (entry2 == NULL) {
+            printf("%p\n", entry->key);
+         }
+      }
+
+      abort();
+   }
+}
+
+static void
+validate_var_decl(nir_variable *var, bool is_global, validate_state *state)
+{
+   assert(is_global != (var->data.mode == nir_var_local));
+
+   /*
+    * TODO validate some things ir_validate.cpp does (requires more GLSL type
+    * support)
+    */
+
+   if (!is_global) {
+      _mesa_hash_table_insert(state->var_defs, var, state->impl);
+   }
+}
+
+static void
+validate_function_impl(nir_function_impl *impl, validate_state *state)
+{
+   assert(impl->overload->impl == impl);
+   assert(impl->cf_node.parent == NULL);
+
+   assert(impl->num_params == impl->overload->num_params);
+   for (unsigned i = 0; i < impl->num_params; i++)
+      assert(impl->params[i]->type == impl->overload->params[i].type);
+
+   if (glsl_type_is_void(impl->overload->return_type))
+      assert(impl->return_var == NULL);
+   else
+      assert(impl->return_var->type == impl->overload->return_type);
+
+   assert(exec_list_is_empty(&impl->end_block->instr_list));
+   assert(impl->end_block->successors[0] == NULL);
+   assert(impl->end_block->successors[1] == NULL);
+
+   state->impl = impl;
+   state->parent_node = &impl->cf_node;
+
+   foreach_list_typed(nir_variable, var, node, &impl->locals) {
+      validate_var_decl(var, false, state);
+   }
+
+   foreach_list_typed(nir_register, reg, node, &impl->registers) {
+      prevalidate_reg_decl(reg, false, state);
+   }
+
+   foreach_list_typed(nir_cf_node, node, node, &impl->body) {
+      validate_cf_node(node, state);
+   }
+
+   foreach_list_typed(nir_register, reg, node, &impl->registers) {
+      postvalidate_reg_decl(reg, state);
+   }
+}
+
+static void
+validate_function_overload(nir_function_overload *overload,
+                           validate_state *state)
+{
+   if (overload->impl != NULL)
+      validate_function_impl(overload->impl, state);
+}
+
+static void
+validate_function(nir_function *func, validate_state *state)
+{
+   foreach_list_typed(nir_function_overload, overload, node, &func->overload_list) {
+      assert(overload->function == func);
+      validate_function_overload(overload, state);
+   }
+}
+
+static void
+init_validate_state(validate_state *state)
+{
+   state->regs = _mesa_hash_table_create(NULL, _mesa_hash_pointer,
+                                         _mesa_key_pointer_equal);
+   state->ssa_defs = _mesa_hash_table_create(NULL, _mesa_hash_pointer,
+                                             _mesa_key_pointer_equal);
+   state->var_defs = _mesa_hash_table_create(NULL, _mesa_hash_pointer,
+                                             _mesa_key_pointer_equal);
+}
+
+static void
+destroy_validate_state(validate_state *state)
+{
+   _mesa_hash_table_destroy(state->regs, NULL);
+   _mesa_hash_table_destroy(state->ssa_defs, NULL);
+   _mesa_hash_table_destroy(state->var_defs, NULL);
+}
+
+void
+nir_validate_shader(nir_shader *shader)
+{
+   validate_state state;
+   init_validate_state(&state);
+
+   struct hash_entry *entry;
+   hash_table_foreach(shader->uniforms, entry) {
+      validate_var_decl((nir_variable *) entry->data, true, &state);
+   }
+
+   hash_table_foreach(shader->inputs, entry) {
+     validate_var_decl((nir_variable *) entry->data, true, &state);
+   }
+
+   hash_table_foreach(shader->outputs, entry) {
+      validate_var_decl((nir_variable *) entry->data, true, &state);
+   }
+
+   foreach_list_typed(nir_variable, var, node, &shader->globals) {
+     validate_var_decl(var, true, &state);
+   }
+
+   foreach_list_typed(nir_variable, var, node, &shader->system_values) {
+     validate_var_decl(var, true, &state);
+   }
+
+   foreach_list_typed(nir_register, reg, node, &shader->registers) {
+      prevalidate_reg_decl(reg, true, &state);
+   }
+
+   foreach_list_typed(nir_function, func, node, &shader->functions) {
+      validate_function(func, &state);
+   }
+
+   foreach_list_typed(nir_register, reg, node, &shader->registers) {
+      postvalidate_reg_decl(reg, &state);
+   }
+
+   destroy_validate_state(&state);
+}