nak: gather instr count explicitly

This isn't as simple as dividing so we want a real shader info property for nvk
to consume. Plumb one through.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: M Henning <drawoc@darkrefraction.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30136>

src/nouveau/compiler/nak.h

@@ -103,6 +103,9 @@ struct nak_shader_info {
 
    uint8_t _pad0;
 
+   /** Number of instructions used */
+   uint32_t num_instrs;
+
    /** Size of shader local (scratch) memory */
    uint32_t slm_size;
 

src/nouveau/compiler/nak/api.rs

@@ -330,7 +330,7 @@ pub extern "C" fn nak_compile_shader(
         eprintln!("NAK IR:\n{}", &s);
     }
 
-    s.gather_global_mem_usage();
+    s.gather_info();
 
     let info = nak_shader_info {
         stage: nir.info.stage(),
@@ -342,6 +342,7 @@ pub extern "C" fn nak_compile_shader(
         },
         num_barriers: s.info.num_barriers,
         _pad0: Default::default(),
+        num_instrs: s.info.num_instrs,
         slm_size: s.info.slm_size,
         __bindgen_anon_1: match &s.info.stage {
             ShaderStageInfo::Compute(cs_info) => {
@@ -457,16 +458,9 @@ pub extern "C" fn nak_compile_shader(
             let c_name = _mesa_shader_stage_to_string(info.stage as u32);
             CStr::from_ptr(c_name).to_str().expect("Invalid UTF-8")
         };
-        let instruction_count = if nak.sm >= 70 {
-            code.len() / 4
-        } else if nak.sm >= 50 {
-            (code.len() / 8) * 3
-        } else {
-            unreachable!()
-        };
 
         eprintln!("Stage: {}", stage_name);
-        eprintln!("Instruction count: {}", instruction_count);
+        eprintln!("Instruction count: {}", info.num_instrs);
         eprintln!("Num GPRs: {}", info.num_gprs);
         eprintln!("SLM size: {}", info.slm_size);
 

src/nouveau/compiler/nak/from_nir.rs

@@ -21,6 +21,7 @@ use std::ops::Index;
 fn init_info_from_nir(nir: &nir_shader) -> ShaderInfo {
     ShaderInfo {
         num_gprs: 0,
+        num_instrs: 0,
         num_barriers: 0,
         slm_size: nir.scratch_size,
         uses_global_mem: false,

src/nouveau/compiler/nak/ir.rs

@@ -6239,6 +6239,7 @@ pub enum ShaderIoInfo {
 pub struct ShaderInfo {
     pub num_gprs: u8,
     pub num_barriers: u8,
+    pub num_instrs: u32,
     pub slm_size: u32,
     pub uses_global_mem: bool,
     pub writes_global_mem: bool,
@@ -6294,15 +6295,14 @@ impl Shader<'_> {
         })
     }
 
-    pub fn gather_global_mem_usage(&mut self) {
-        if let ShaderStageInfo::Compute(_) = self.info.stage {
-            return;
-        }
-
+    pub fn gather_info(&mut self) {
+        let mut num_instrs = 0;
         let mut uses_global_mem = false;
         let mut writes_global_mem = false;
 
         self.for_each_instr(&mut |instr| {
+            num_instrs += 1;
+
             if !uses_global_mem {
                 uses_global_mem = instr.uses_global_mem();
             }
@@ -6312,6 +6312,7 @@ impl Shader<'_> {
             }
         });
 
+        self.info.num_instrs = num_instrs;
         self.info.uses_global_mem = uses_global_mem;
         self.info.writes_global_mem = writes_global_mem;
     }