llvmpipe: add shader clock support

Add support for calling out to the os time functions from the llvm side.

Reviewed-by: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/17868>

docs/features.txt

@@ -307,7 +307,7 @@ Khronos, ARB, and OES extensions that are not part of any OpenGL or OpenGL ES ve
   GL_ARB_sample_locations                               DONE (nvc0, zink)
   GL_ARB_seamless_cubemap_per_texture                   DONE (etnaviv/SEAMLESS_CUBE_MAP, freedreno, i965, nvc0, r600, radeonsi, softpipe, virgl, zink)
   GL_ARB_shader_ballot                                  DONE (i965/gen8+, nvc0, radeonsi, zink)
-  GL_ARB_shader_clock                                   DONE (i965/gen7+, nv50, nvc0, r600, radeonsi, virgl, zink)
+  GL_ARB_shader_clock                                   DONE (i965/gen7+, nv50, nvc0, r600, radeonsi, llvmpipe, virgl, zink)
   GL_ARB_shader_stencil_export                          DONE (i965/gen9+, r600, radeonsi, softpipe, llvmpipe, virgl, panfrost, zink)
   GL_ARB_shader_viewport_layer_array                    DONE (i965/gen6+, nvc0, radeonsi, zink)
   GL_ARB_shading_language_include                       DONE

docs/relnotes/new_features.txt

@@ -0,0 +1 @@
+GL_ARB_shader_clock on llvmpipe

src/gallium/auxiliary/gallivm/lp_bld_init.c

@@ -569,6 +569,14 @@ gallivm_verify_function(struct gallivm_state *gallivm,
    }
 }
 
+void lp_init_clock_hook(struct gallivm_state *gallivm)
+{
+   if (gallivm->get_time_hook)
+      return;
+
+   LLVMTypeRef get_time_type = LLVMFunctionType(LLVMInt64TypeInContext(gallivm->context), NULL, 0, 1);
+   gallivm->get_time_hook = LLVMAddFunction(gallivm->module, "get_time_hook", get_time_type);
+}
 
 /**
  * Compile a module.
@@ -693,6 +701,8 @@ gallivm_compile_module(struct gallivm_state *gallivm)
    lp_init_printf_hook(gallivm);
    LLVMAddGlobalMapping(gallivm->engine, gallivm->debug_printf_hook, debug_printf);
 
+   lp_init_clock_hook(gallivm);
+   LLVMAddGlobalMapping(gallivm->engine, gallivm->get_time_hook, os_time_get_nano);
 
    if (gallivm_debug & GALLIVM_DEBUG_ASM) {
       LLVMValueRef llvm_func = LLVMGetFirstFunction(gallivm->module);

src/gallium/auxiliary/gallivm/lp_bld_init.h

@@ -64,6 +64,8 @@ struct gallivm_state
 
    LLVMTypeRef coro_malloc_hook_type;
    LLVMTypeRef coro_free_hook_type;
+
+   LLVMValueRef get_time_hook;
 };
 
 
@@ -94,6 +96,7 @@ gallivm_jit_function(struct gallivm_state *gallivm,
 
 unsigned gallivm_get_perf_flags(void);
 
+void lp_init_clock_hook(struct gallivm_state *gallivm);
 #ifdef __cplusplus
 }
 #endif

src/gallium/auxiliary/gallivm/lp_bld_nir.c

@@ -2203,6 +2203,9 @@ visit_intrinsic(struct lp_build_nir_context *bld_base,
    case nir_intrinsic_store_scratch:
       visit_store_scratch(bld_base, instr);
       break;
+   case nir_intrinsic_shader_clock:
+      bld_base->clock(bld_base, result);
+      break;
    default:
       fprintf(stderr, "Unsupported intrinsic: ");
       nir_print_instr(&instr->instr, stderr);

src/gallium/auxiliary/gallivm/lp_bld_nir.h

@@ -222,6 +222,7 @@ struct lp_build_nir_context
                            LLVMValueRef dst[4]);
    void (*helper_invocation)(struct lp_build_nir_context *bld_base, LLVMValueRef *dst);
 
+   void (*clock)(struct lp_build_nir_context *bld_Base, LLVMValueRef dst[4]);
    void (*interp_at)(struct lp_build_nir_context *bld_base,
                      unsigned num_components,
                      nir_variable *var,

src/gallium/auxiliary/gallivm/lp_bld_nir_soa.c

@@ -2642,6 +2642,25 @@ emit_store_scratch(struct lp_build_nir_context *bld_base,
    }
 }
 
+static void
+emit_clock(struct lp_build_nir_context *bld_base,
+           LLVMValueRef dst[4])
+{
+   struct gallivm_state *gallivm = bld_base->base.gallivm;
+   LLVMBuilderRef builder = gallivm->builder;
+   struct lp_build_context *uint_bld = get_int_bld(bld_base, true, 32);
+
+   lp_init_clock_hook(gallivm);
+
+   LLVMValueRef result = LLVMBuildCall(builder, gallivm->get_time_hook, NULL, 0, "");
+
+   LLVMValueRef hi = LLVMBuildShl(builder, result, lp_build_const_int64(gallivm, 32), "");
+   hi = LLVMBuildTrunc(builder, hi, uint_bld->elem_type, "");
+   LLVMValueRef lo = LLVMBuildTrunc(builder, result, uint_bld->elem_type, "");
+   dst[0] = lp_build_broadcast_scalar(uint_bld, lo);
+   dst[1] = lp_build_broadcast_scalar(uint_bld, hi);
+}
+
 void lp_build_nir_soa(struct gallivm_state *gallivm,
                       struct nir_shader *shader,
                       const struct lp_build_tgsi_params *params,
@@ -2755,6 +2774,7 @@ void lp_build_nir_soa(struct gallivm_state *gallivm,
    bld.bld_base.load_scratch = emit_load_scratch;
    bld.bld_base.store_scratch = emit_store_scratch;
    bld.bld_base.load_const = emit_load_const;
+   bld.bld_base.clock = emit_clock;
 
    bld.mask = params->mask;
    bld.inputs = params->inputs;

src/gallium/drivers/llvmpipe/lp_screen.c

@@ -361,6 +361,7 @@ llvmpipe_get_param(struct pipe_screen *screen, enum pipe_cap param)
    case PIPE_CAP_SAMPLE_SHADING:
    case PIPE_CAP_GL_SPIRV:
    case PIPE_CAP_POST_DEPTH_COVERAGE:
+   case PIPE_CAP_SHADER_CLOCK:
    case PIPE_CAP_PACKED_UNIFORMS: {
       struct llvmpipe_screen *lscreen = llvmpipe_screen(screen);
       return !lscreen->use_tgsi;