[Mesa-dev] [PATCH 4/6] ac/nir: rewrite shared variable handling
Bas Nieuwenhuizen
bas at basnieuwenhuizen.nl
Thu Jul 6 21:18:05 UTC 2017
Patches 3-4 look technically correct to me, so for just using it for shared vars
Reviewed-by: Bas Nieuwenhuizen <bas at basnieuwenhuizen>
On Thu, Jul 6, 2017 at 9:48 PM, Connor Abbott <connora at valvesoftware.com> wrote:
> From: Connor Abbott <cwabbott0 at gmail.com>
>
> Similar to before, do the direct NIR->LLVM translation instead of
> lowering to an array then back to a variable. This should fix indirect
> dereferences, make shared variables more tightly packed, and make LLVM's
> alias analysis more precise.
> ---
> src/amd/common/ac_nir_to_llvm.c | 116 ++++++++--------------------------------
> 1 file changed, 23 insertions(+), 93 deletions(-)
>
> diff --git a/src/amd/common/ac_nir_to_llvm.c b/src/amd/common/ac_nir_to_llvm.c
> index f42d214..743cc1d 100644
> --- a/src/amd/common/ac_nir_to_llvm.c
> +++ b/src/amd/common/ac_nir_to_llvm.c
> @@ -155,7 +155,6 @@ struct nir_to_llvm_context {
> LLVMValueRef inputs[RADEON_LLVM_MAX_INPUTS * 4];
> LLVMValueRef outputs[RADEON_LLVM_MAX_OUTPUTS * 4];
>
> - LLVMValueRef shared_memory;
> uint64_t input_mask;
> uint64_t output_mask;
> uint8_t num_output_clips;
> @@ -386,23 +385,6 @@ static LLVMTypeRef const_array(LLVMTypeRef elem_type, int num_elements)
> CONST_ADDR_SPACE);
> }
>
> -static LLVMValueRef get_shared_memory_ptr(struct nir_to_llvm_context *ctx,
> - int idx,
> - LLVMTypeRef type)
> -{
> - LLVMValueRef offset;
> - LLVMValueRef ptr;
> - int addr_space;
> -
> - offset = LLVMConstInt(ctx->i32, idx * 16, false);
> -
> - ptr = ctx->shared_memory;
> - ptr = LLVMBuildGEP(ctx->builder, ptr, &offset, 1, "");
> - addr_space = LLVMGetPointerAddressSpace(LLVMTypeOf(ptr));
> - ptr = LLVMBuildBitCast(ctx->builder, ptr, LLVMPointerType(type, addr_space), "");
> - return ptr;
> -}
> -
> static LLVMTypeRef to_integer_type_scalar(struct ac_llvm_context *ctx, LLVMTypeRef t)
> {
> if (t == ctx->f16 || t == ctx->i16)
> @@ -2986,7 +2968,8 @@ static LLVMValueRef visit_load_var(struct nir_to_llvm_context *ctx,
> values[chan] = ctx->inputs[idx + chan + const_index * 4];
> }
> break;
> - case nir_var_local: {
> + case nir_var_local:
> + case nir_var_shared: {
> LLVMValueRef address = build_gep_for_deref(ctx,
> instr->variables[0]);
> LLVMValueRef val = LLVMBuildLoad(ctx->builder, address, "");
> @@ -3016,23 +2999,6 @@ static LLVMValueRef visit_load_var(struct nir_to_llvm_context *ctx,
> }
> }
> break;
> - case nir_var_shared: {
> - LLVMValueRef ptr = get_shared_memory_ptr(ctx, idx, ctx->i32);
> - LLVMValueRef derived_ptr;
> -
> - if (indir_index)
> - indir_index = LLVMBuildMul(ctx->builder, indir_index, LLVMConstInt(ctx->i32, 4, false), "");
> -
> - for (unsigned chan = 0; chan < ve; chan++) {
> - LLVMValueRef index = LLVMConstInt(ctx->i32, chan, false);
> - if (indir_index)
> - index = LLVMBuildAdd(ctx->builder, index, indir_index, "");
> - derived_ptr = LLVMBuildGEP(ctx->builder, ptr, &index, 1, "");
> -
> - values[chan] = LLVMBuildLoad(ctx->builder, derived_ptr, "");
> - }
> - break;
> - }
> default:
> unreachable("unhandle variable mode");
> }
> @@ -3107,7 +3073,8 @@ visit_store_var(struct nir_to_llvm_context *ctx,
> }
> }
> break;
> - case nir_var_local: {
> + case nir_var_local:
> + case nir_var_shared: {
> int writemask = instr->const_index[0];
> LLVMValueRef address = build_gep_for_deref(ctx,
> instr->variables[0]);
> @@ -3137,28 +3104,6 @@ visit_store_var(struct nir_to_llvm_context *ctx,
> }
> break;
> }
> - case nir_var_shared: {
> - LLVMValueRef ptr = get_shared_memory_ptr(ctx, idx, ctx->i32);
> -
> - if (indir_index)
> - indir_index = LLVMBuildMul(ctx->builder, indir_index, LLVMConstInt(ctx->i32, 4, false), "");
> -
> - for (unsigned chan = 0; chan < 8; chan++) {
> - if (!(writemask & (1 << chan)))
> - continue;
> - LLVMValueRef index = LLVMConstInt(ctx->i32, chan, false);
> - LLVMValueRef derived_ptr;
> -
> - if (indir_index)
> - index = LLVMBuildAdd(ctx->builder, index, indir_index, "");
> -
> - value = llvm_extract_elem(ctx, src, chan);
> - derived_ptr = LLVMBuildGEP(ctx->builder, ptr, &index, 1, "");
> - LLVMBuildStore(ctx->builder,
> - to_integer(&ctx->ac, value), derived_ptr);
> - }
> - break;
> - }
> default:
> break;
> }
> @@ -3637,9 +3582,8 @@ static LLVMValueRef visit_var_atomic(struct nir_to_llvm_context *ctx,
> const nir_intrinsic_instr *instr)
> {
> LLVMValueRef ptr, result;
> - int idx = instr->variables[0]->var->data.driver_location;
> LLVMValueRef src = get_src(ctx, instr->src[0]);
> - ptr = get_shared_memory_ptr(ctx, idx, ctx->i32);
> + ptr = build_gep_for_deref(ctx, instr->variables[0]);
>
> if (instr->intrinsic == nir_intrinsic_var_atomic_comp_swap) {
> LLVMValueRef src1 = get_src(ctx, instr->src[1]);
> @@ -5114,6 +5058,20 @@ setup_locals(struct nir_to_llvm_context *ctx,
> }
> }
>
> +static void
> +setup_shared(struct nir_to_llvm_context *ctx,
> + struct nir_shader *nir)
> +{
> + nir_foreach_variable(variable, &nir->shared) {
> + LLVMValueRef shared =
> + LLVMAddGlobalInAddressSpace(
> + ctx->module, glsl_to_llvm_type(ctx, variable->type),
> + variable->name ? variable->name : "",
> + LOCAL_ADDR_SPACE);
> + _mesa_hash_table_insert(ctx->vars, variable, shared);
> + }
> +}
> +
> static LLVMValueRef
> emit_float_saturate(struct ac_llvm_context *ctx, LLVMValueRef v, float lo, float hi)
> {
> @@ -5907,15 +5865,6 @@ handle_shader_outputs_post(struct nir_to_llvm_context *ctx)
> }
> }
>
> -static void
> -handle_shared_compute_var(struct nir_to_llvm_context *ctx,
> - struct nir_variable *variable, uint32_t *offset, int idx)
> -{
> - unsigned size = glsl_count_attribute_slots(variable->type, false);
> - variable->data.driver_location = *offset;
> - *offset += size;
> -}
> -
> static void ac_llvm_finalize_module(struct nir_to_llvm_context * ctx)
> {
> LLVMPassManagerRef passmgr;
> @@ -6072,29 +6021,7 @@ LLVMModuleRef ac_translate_nir_to_llvm(LLVMTargetMachineRef tm,
>
> create_function(&ctx);
>
> - if (nir->stage == MESA_SHADER_COMPUTE) {
> - int num_shared = 0;
> - nir_foreach_variable(variable, &nir->shared)
> - num_shared++;
> - if (num_shared) {
> - int idx = 0;
> - uint32_t shared_size = 0;
> - LLVMValueRef var;
> - LLVMTypeRef i8p = LLVMPointerType(ctx.i8, LOCAL_ADDR_SPACE);
> - nir_foreach_variable(variable, &nir->shared) {
> - handle_shared_compute_var(&ctx, variable, &shared_size, idx);
> - idx++;
> - }
> -
> - shared_size *= 16;
> - var = LLVMAddGlobalInAddressSpace(ctx.module,
> - LLVMArrayType(ctx.i8, shared_size),
> - "compute_lds",
> - LOCAL_ADDR_SPACE);
> - LLVMSetAlignment(var, 4);
> - ctx.shared_memory = LLVMBuildBitCast(ctx.builder, var, i8p, "");
> - }
> - } else if (nir->stage == MESA_SHADER_GEOMETRY) {
> + if (nir->stage == MESA_SHADER_GEOMETRY) {
> ctx.gs_next_vertex = ac_build_alloca(&ctx, ctx.i32, "gs_next_vertex");
>
> ctx.gs_max_out_vertices = nir->info.gs.vertices_out;
> @@ -6127,6 +6054,9 @@ LLVMModuleRef ac_translate_nir_to_llvm(LLVMTargetMachineRef tm,
>
> setup_locals(&ctx, func);
>
> + if (nir->stage == MESA_SHADER_COMPUTE)
> + setup_shared(&ctx, nir);
> +
> visit_cf_list(&ctx, &func->impl->body);
> phi_post_pass(&ctx);
>
> --
> 2.9.4
>
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