[Mesa-dev] [PATCH 1/3] nir: Add asserts to the casting functions

[Jason Ekstrand]

This makes calling nir_foo_as_bar a bit safer because we're no longer 100%
trusting in the caller to ensure that it's safe.  The caller still needs to
do the right thing but this ensures that we catch invalid casts with an
assert rather than by reading garbage data.  The one downside is that we do
use the casts a bit in nir_validate and it's not a validate_assert.

Signed-off-by: Jason Ekstrand <jason at jlekstrand.net>
---
 src/compiler/nir/nir.h        | 60 ++++++++++++++++++++++++++++---------------
 src/compiler/nir/nir_search.h |  9 ++++---
 2 files changed, 45 insertions(+), 24 deletions(-)

diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index 8d1afb9..a122f12 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -59,11 +59,13 @@ struct gl_shader_program;
  * Note that you have to be a bit careful as the generated cast function
  * destroys constness.
  */
-#define NIR_DEFINE_CAST(name, in_type, out_type, field)  \
-static inline out_type *                                 \
-name(const in_type *parent)                              \
-{                                                        \
-   return exec_node_data(out_type, parent, field);       \
+#define NIR_DEFINE_CAST(name, in_type, out_type, field, \
+                        type_field, type_value)         \
+static inline out_type *                                \
+name(const in_type *parent)                             \
+{                                                       \
+   assert(parent && parent->type_field == type_value);  \
+   return exec_node_data(out_type, parent, field);      \
 }
 
 struct nir_function;
@@ -841,9 +843,12 @@ typedef struct {
    unsigned index;
 } nir_deref_struct;
 
-NIR_DEFINE_CAST(nir_deref_as_var, nir_deref, nir_deref_var, deref)
-NIR_DEFINE_CAST(nir_deref_as_array, nir_deref, nir_deref_array, deref)
-NIR_DEFINE_CAST(nir_deref_as_struct, nir_deref, nir_deref_struct, deref)
+NIR_DEFINE_CAST(nir_deref_as_var, nir_deref, nir_deref_var, deref,
+                deref_type, nir_deref_type_var)
+NIR_DEFINE_CAST(nir_deref_as_array, nir_deref, nir_deref_array, deref,
+                deref_type, nir_deref_type_array)
+NIR_DEFINE_CAST(nir_deref_as_struct, nir_deref, nir_deref_struct, deref,
+                deref_type, nir_deref_type_struct)
 
 /* Returns the last deref in the chain. */
 static inline nir_deref *
@@ -1409,16 +1414,25 @@ typedef struct {
    struct exec_list entries;
 } nir_parallel_copy_instr;
 
-NIR_DEFINE_CAST(nir_instr_as_alu, nir_instr, nir_alu_instr, instr)
-NIR_DEFINE_CAST(nir_instr_as_call, nir_instr, nir_call_instr, instr)
-NIR_DEFINE_CAST(nir_instr_as_jump, nir_instr, nir_jump_instr, instr)
-NIR_DEFINE_CAST(nir_instr_as_tex, nir_instr, nir_tex_instr, instr)
-NIR_DEFINE_CAST(nir_instr_as_intrinsic, nir_instr, nir_intrinsic_instr, instr)
-NIR_DEFINE_CAST(nir_instr_as_load_const, nir_instr, nir_load_const_instr, instr)
-NIR_DEFINE_CAST(nir_instr_as_ssa_undef, nir_instr, nir_ssa_undef_instr, instr)
-NIR_DEFINE_CAST(nir_instr_as_phi, nir_instr, nir_phi_instr, instr)
+NIR_DEFINE_CAST(nir_instr_as_alu, nir_instr, nir_alu_instr, instr,
+                type, nir_instr_type_alu)
+NIR_DEFINE_CAST(nir_instr_as_call, nir_instr, nir_call_instr, instr,
+                type, nir_instr_type_call)
+NIR_DEFINE_CAST(nir_instr_as_jump, nir_instr, nir_jump_instr, instr,
+                type, nir_instr_type_jump)
+NIR_DEFINE_CAST(nir_instr_as_tex, nir_instr, nir_tex_instr, instr,
+                type, nir_instr_type_tex)
+NIR_DEFINE_CAST(nir_instr_as_intrinsic, nir_instr, nir_intrinsic_instr, instr,
+                type, nir_instr_type_intrinsic)
+NIR_DEFINE_CAST(nir_instr_as_load_const, nir_instr, nir_load_const_instr, instr,
+                type, nir_instr_type_load_const)
+NIR_DEFINE_CAST(nir_instr_as_ssa_undef, nir_instr, nir_ssa_undef_instr, instr,
+                type, nir_instr_type_ssa_undef)
+NIR_DEFINE_CAST(nir_instr_as_phi, nir_instr, nir_phi_instr, instr,
+                type, nir_instr_type_phi)
 NIR_DEFINE_CAST(nir_instr_as_parallel_copy, nir_instr,
-                nir_parallel_copy_instr, instr)
+                nir_parallel_copy_instr, instr,
+                type, nir_instr_type_parallel_copy)
 
 /*
  * Control flow
@@ -1660,10 +1674,14 @@ nir_cf_node_is_last(const nir_cf_node *node)
    return exec_node_is_tail_sentinel(node->node.next);
 }
 
-NIR_DEFINE_CAST(nir_cf_node_as_block, nir_cf_node, nir_block, cf_node)
-NIR_DEFINE_CAST(nir_cf_node_as_if, nir_cf_node, nir_if, cf_node)
-NIR_DEFINE_CAST(nir_cf_node_as_loop, nir_cf_node, nir_loop, cf_node)
-NIR_DEFINE_CAST(nir_cf_node_as_function, nir_cf_node, nir_function_impl, cf_node)
+NIR_DEFINE_CAST(nir_cf_node_as_block, nir_cf_node, nir_block, cf_node,
+                type, nir_cf_node_block)
+NIR_DEFINE_CAST(nir_cf_node_as_if, nir_cf_node, nir_if, cf_node,
+                type, nir_cf_node_if)
+NIR_DEFINE_CAST(nir_cf_node_as_loop, nir_cf_node, nir_loop, cf_node,
+                type, nir_cf_node_loop)
+NIR_DEFINE_CAST(nir_cf_node_as_function, nir_cf_node,
+                nir_function_impl, cf_node, type, nir_cf_node_function)
 
 typedef enum {
    nir_parameter_in,
diff --git a/src/compiler/nir/nir_search.h b/src/compiler/nir/nir_search.h
index f55d797..dec19d5 100644
--- a/src/compiler/nir/nir_search.h
+++ b/src/compiler/nir/nir_search.h
@@ -106,11 +106,14 @@ typedef struct {
 } nir_search_expression;
 
 NIR_DEFINE_CAST(nir_search_value_as_variable, nir_search_value,
-                nir_search_variable, value)
+                nir_search_variable, value,
+                type, nir_search_value_variable)
 NIR_DEFINE_CAST(nir_search_value_as_constant, nir_search_value,
-                nir_search_constant, value)
+                nir_search_constant, value,
+                type, nir_search_value_constant)
 NIR_DEFINE_CAST(nir_search_value_as_expression, nir_search_value,
-                nir_search_expression, value)
+                nir_search_expression, value,
+                type, nir_search_value_expression)
 
 nir_alu_instr *
 nir_replace_instr(nir_alu_instr *instr, const nir_search_expression *search,
-- 
2.5.0.400.gff86faf