[Mesa-dev] [PATCH v3 11/18] mesa/macros: add power-of-two assertions for alignment macros

[Nanley Chery]

From: Nanley Chery <nanley.g.chery at intel.com>

ALIGN and ROUND_DOWN_TO both require that the alignment value passed
into the macro be a power of two in the comments. Using software assertions
verifies this to be the case.

v2: use static inline functions instead of gcc-specific statement expressions.

Signed-off-by: Nanley Chery <nanley.g.chery at intel.com>
---
 src/mesa/drivers/dri/i965/brw_fs_nir.cpp |  2 +-
 src/mesa/main/macros.h                   | 16 +++++++++++++---
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
index 59081ea..1a57784 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
@@ -134,7 +134,7 @@ fs_visitor::nir_setup_outputs(nir_shader *shader)
                                : var->type->vector_elements;
 
       if (stage == MESA_SHADER_VERTEX) {
-         for (int i = 0; i < ALIGN(type_size(var->type), 4) / 4; i++) {
+         for (unsigned int i = 0; i < ALIGN(type_size(var->type), 4) / 4; i++) {
             int output = var->data.location + i;
             this->outputs[output] = offset(reg, 4 * i);
             this->output_components[output] = vector_elements;
diff --git a/src/mesa/main/macros.h b/src/mesa/main/macros.h
index 0608650..4a640ad 100644
--- a/src/mesa/main/macros.h
+++ b/src/mesa/main/macros.h
@@ -684,7 +684,7 @@ minify(unsigned value, unsigned levels)
  * Note that this considers 0 a power of two.
  */
 static inline bool
-is_power_of_two(unsigned value)
+is_power_of_two(uintptr_t value)
 {
    return (value & (value - 1)) == 0;
 }
@@ -700,7 +700,12 @@ is_power_of_two(unsigned value)
  *
  * \sa ROUND_DOWN_TO()
  */
-#define ALIGN(value, alignment)  (((value) + (alignment) - 1) & ~((alignment) - 1))
+static inline uintptr_t
+ALIGN(uintptr_t value, uintptr_t alignment)
+{
+      assert(is_power_of_two(alignment));
+      return (((value) + (alignment) - 1) & ~((alignment) - 1));
+}
 
 /**
  * Align a value down to an alignment value
@@ -713,7 +718,12 @@ is_power_of_two(unsigned value)
  *
  * \sa ALIGN()
  */
-#define ROUND_DOWN_TO(value, alignment) ((value) & ~(alignment - 1))
+static inline uintptr_t
+ROUND_DOWN_TO(uintptr_t value, uintptr_t alignment)
+{
+      assert(is_power_of_two(alignment));
+      return ((value) & ~(alignment - 1));
+}
 
 
 /** Cross product of two 3-element vectors */
-- 
2.4.2