Mesa (master): mesa/macros: add power-of-two assertions for alignment macros

[Nanley Chery]

Module: Mesa
Branch: master
Commit: 97f4efd573aed7ffc0ea9395f4e69ccdeb5041f6
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=97f4efd573aed7ffc0ea9395f4e69ccdeb5041f6

Author: Nanley Chery <nanley.g.chery at intel.com>
Date:   Wed May 27 13:25:30 2015 -0700

mesa/macros: add power-of-two assertions for alignment macros

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 (Brian).
v3: fix indendation (Brian).
v4: add greater than zero requirement (Anuj).

Reviewed-by: Anuj Phogat <anuj.phogat at gmail.com>
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                   |   14 ++++++++++++--
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
index a62dbb8..430efb3 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
@@ -131,7 +131,7 @@ fs_visitor::nir_setup_outputs(nir_shader *shader)
 
       switch (stage) {
       case MESA_SHADER_VERTEX:
-         for (int i = 0; i < ALIGN(type_size_scalar(var->type), 4) / 4; i++) {
+         for (unsigned int i = 0; i < ALIGN(type_size_scalar(var->type), 4) / 4; i++) {
             int output = var->data.location + i;
             this->outputs[output] = offset(reg, bld, 4 * i);
             this->output_components[output] = vector_elements;
diff --git a/src/mesa/main/macros.h b/src/mesa/main/macros.h
index 54df50c..c3ef42a 100644
--- a/src/mesa/main/macros.h
+++ b/src/mesa/main/macros.h
@@ -690,7 +690,12 @@ minify(unsigned value, unsigned levels)
  *
  * \sa ROUND_DOWN_TO()
  */
-#define ALIGN(value, alignment)  (((value) + (alignment) - 1) & ~((alignment) - 1))
+static inline uintptr_t
+ALIGN(uintptr_t value, int32_t alignment)
+{
+   assert((alignment > 0) && _mesa_is_pow_two(alignment));
+   return (((value) + (alignment) - 1) & ~((alignment) - 1));
+}
 
 /**
  * Align a value down to an alignment value
@@ -703,7 +708,12 @@ minify(unsigned value, unsigned levels)
  *
  * \sa ALIGN()
  */
-#define ROUND_DOWN_TO(value, alignment) ((value) & ~(alignment - 1))
+static inline uintptr_t
+ROUND_DOWN_TO(uintptr_t value, int32_t alignment)
+{
+   assert((alignment > 0) && _mesa_is_pow_two(alignment));
+   return ((value) & ~(alignment - 1));
+}
 
 
 /** Cross product of two 3-element vectors */