[Mesa-dev] [PATCH 02/13] i965: Allow passing target_bo=NULL to brw_emit_reloc()

[Chris Wilson]

Sometimes we want to emit a relocation to a NULL surface when the
constructing the batch. If we push the NULL handling into the common
brw_emit_reloc() we can make the batch construction itself more
readable.

On the other hand, we often test for the existence of the bo separately
and so would like to skip that extra test for !bo, so we also add
__brw_emit_reloc that can depend upon bo being valid.

Cc: Kenneth Graunke <kenneth at whitecape.org>
Cc: Matt Turner <mattst88 at gmail.com>
Cc: Jason Ekstrand <jason.ekstrand at intel.com>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 src/mesa/drivers/dri/i965/intel_batchbuffer.c |  6 +++---
 src/mesa/drivers/dri/i965/intel_batchbuffer.h | 30 ++++++++++++++++++++-------
 2 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/intel_batchbuffer.c b/src/mesa/drivers/dri/i965/intel_batchbuffer.c
index 7af7d9b0a3..81cd578b28 100644
--- a/src/mesa/drivers/dri/i965/intel_batchbuffer.c
+++ b/src/mesa/drivers/dri/i965/intel_batchbuffer.c
@@ -752,11 +752,11 @@ brw_batch_references(struct intel_batchbuffer *batch, struct brw_bo *bo)
 /*  This is the only way buffers get added to the validate list.
  */
 uint64_t
-brw_emit_reloc(struct intel_batchbuffer *batch, uint32_t batch_offset,
+__brw_emit_reloc(struct intel_batchbuffer *batch, uint32_t batch_offset,
                struct brw_bo *target, uint32_t target_offset,
                uint32_t read_domains, uint32_t write_domain)
 {
-   uint64_t offset64;
+   assert(target);
 
    if (batch->reloc_count == batch->reloc_array_size) {
       batch->reloc_array_size *= 2;
@@ -778,7 +778,7 @@ brw_emit_reloc(struct intel_batchbuffer *batch, uint32_t batch_offset,
    batch->reloc_count++;
 
    /* ensure gcc doesn't reload */
-   offset64 = *((volatile uint64_t *)&target->offset64);
+   uint64_t offset64 = *((volatile uint64_t *)&target->offset64);
    reloc->offset = batch_offset;
    reloc->delta = target_offset;
    reloc->target_handle = target->gem_handle;
diff --git a/src/mesa/drivers/dri/i965/intel_batchbuffer.h b/src/mesa/drivers/dri/i965/intel_batchbuffer.h
index f1a5c1fd51..684c9f359c 100644
--- a/src/mesa/drivers/dri/i965/intel_batchbuffer.h
+++ b/src/mesa/drivers/dri/i965/intel_batchbuffer.h
@@ -70,9 +70,25 @@ bool brw_batch_has_aperture_space(struct brw_context *brw,
 
 bool brw_batch_references(struct intel_batchbuffer *batch, struct brw_bo *bo);
 
-uint64_t brw_emit_reloc(struct intel_batchbuffer *batch, uint32_t batch_offset,
-                        struct brw_bo *target, uint32_t target_offset,
-                        uint32_t read_domains, uint32_t write_domain);
+uint64_t __brw_emit_reloc(struct intel_batchbuffer *batch,
+                          uint32_t batch_offset,
+                          struct brw_bo *target,
+                          uint32_t target_offset,
+                          uint32_t read_domains,
+                          uint32_t write_domain);
+
+static inline uint64_t
+brw_emit_reloc(struct intel_batchbuffer *batch, uint32_t batch_offset,
+               struct brw_bo *target, uint32_t target_offset,
+               uint32_t read_domains, uint32_t write_domain)
+{
+   if (!target)
+      return target_offset;
+
+   return __brw_emit_reloc(batch, batch_offset,
+                           target, target_offset,
+                           read_domains, write_domain);
+}
 
 #define USED_BATCH(batch) ((uintptr_t)((batch).map_next - (batch).map))
 
@@ -161,8 +177,8 @@ intel_batchbuffer_advance(struct brw_context *brw)
 #define OUT_RELOC(buf, read_domains, write_domain, delta) do {          \
    uint32_t __offset = (__map - brw->batch.map) * 4;                    \
    uint32_t reloc =                                                     \
-      brw_emit_reloc(&brw->batch, __offset, (buf), (delta),             \
-                     (read_domains), (write_domain));                   \
+      __brw_emit_reloc(&brw->batch, __offset, (buf), (delta),           \
+                       (read_domains), (write_domain));                 \
    OUT_BATCH(reloc);                                                    \
 } while (0)
 
@@ -170,8 +186,8 @@ intel_batchbuffer_advance(struct brw_context *brw)
 #define OUT_RELOC64(buf, read_domains, write_domain, delta) do {        \
    uint32_t __offset = (__map - brw->batch.map) * 4;                    \
    uint64_t reloc64 =                                                   \
-      brw_emit_reloc(&brw->batch, __offset, (buf), (delta),             \
-                     (read_domains), (write_domain));                   \
+      __brw_emit_reloc(&brw->batch, __offset, (buf), (delta),           \
+                       (read_domains), (write_domain));                 \
    OUT_BATCH(reloc64);                                                  \
    OUT_BATCH(reloc64 >> 32);                                            \
 } while (0)
-- 
2.13.3