i965/fs: Make get_timestamp() pass back the MOV rather than emitting it.

This makes another part of the INTEL_DEBUG=shader_time code emittable
at arbitrary locations, rather than just at the end of the instruction
stream.

v2: Don't lose smear!  Caught by Topi Pohjolainen.
v3: Don't set smear on the destination of the MOV.  Thanks Topi!

Signed-off-by: Kenneth Graunke <[email protected]>
Reviewed-by: Matt Turner <[email protected]>
Cc: [email protected]
(cherry picked from commit e43af8d09f919d02b5ac0810c1c0f1783cbef6ef)

2 files changed, 16 insertions, 5 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 347bdb9852e..a2bfaf225bb 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -678,8 +678,14 @@ fs_visitor::type_size(const struct glsl_type *type)
    return 0;
 }
 
+/**
+ * Create a MOV to read the timestamp register.
+ *
+ * The caller is responsible for emitting the MOV.  The return value is
+ * the destination of the MOV, with extra parameters set.
+ */
 fs_reg
-fs_visitor::get_timestamp()
+fs_visitor::get_timestamp(fs_inst **out_mov)
 {
    assert(brw->gen >= 7);
 
@@ -690,7 +696,7 @@ fs_visitor::get_timestamp()
 
    fs_reg dst = fs_reg(GRF, virtual_grf_alloc(1), BRW_REGISTER_TYPE_UD, 4);
 
-   fs_inst *mov = emit(MOV(dst, ts));
+   fs_inst *mov = MOV(dst, ts);
    /* We want to read the 3 fields we care about even if it's not enabled in
     * the dispatch.
     */
@@ -708,6 +714,7 @@ fs_visitor::get_timestamp()
     */
    dst.set_smear(0);
 
+   *out_mov = mov;
    return dst;
 }
 
@@ -715,7 +722,9 @@ void
 fs_visitor::emit_shader_time_begin()
 {
    current_annotation = "shader time start";
-   shader_start_time = get_timestamp();
+   fs_inst *mov;
+   shader_start_time = get_timestamp(&mov);
+   emit(mov);
 }
 
 void
@@ -751,7 +760,9 @@ fs_visitor::emit_shader_time_end()
       unreachable("fs_visitor::emit_shader_time_end missing code");
    }
 
-   fs_reg shader_end_time = get_timestamp();
+   fs_inst *tm_read;
+   fs_reg shader_end_time = get_timestamp(&tm_read);
+   emit(tm_read);
 
    /* Check that there weren't any timestamp reset events (assuming these
     * were the only two timestamp reads that happened).
diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h
index fcc8a5aca2a..bf8bb0b7343 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.h
+++ b/src/mesa/drivers/dri/i965/brw_fs.h
@@ -622,7 +622,7 @@ public:
    void resolve_ud_negate(fs_reg *reg);
    void resolve_bool_comparison(ir_rvalue *rvalue, fs_reg *reg);
 
-   fs_reg get_timestamp();
+   fs_reg get_timestamp(fs_inst **out_mov);
 
    struct brw_reg interp_reg(int location, int channel);
    void setup_uniform_values(ir_variable *ir);