From e0d3977e19342118a6e71f52c6731adad7e64cb9 Mon Sep 17 00:00:00 2001
From: Dag Lem <dag@nimrod.no>
Date: Thu, 28 Dec 2023 00:23:59 +0100
Subject: [PATCH] Add support for $dimensions and $unpacked_dimensions

---
 frontends/ast/simplify.cc        | 19 ++++++++++++++++---
 tests/sat/sizebits.sv            | 18 ++++++++++++++++++
 tests/svtypes/struct_sizebits.sv | 12 ++++++++++++
 3 files changed, 46 insertions(+), 3 deletions(-)

diff --git a/frontends/ast/simplify.cc b/frontends/ast/simplify.cc
index 7486f676e..04d9af4d1 100644
--- a/frontends/ast/simplify.cc
+++ b/frontends/ast/simplify.cc
@@ -3487,10 +3487,11 @@ skip_dynamic_range_lvalue_expansion:;
 				goto apply_newNode;
 			}
 
-			if (str == "\\$increment" || str == "\\$size" || str == "\\$bits" || str == "\\$high" || str == "\\$low" || str == "\\$left" || str == "\\$right")
+			if (str == "\\$dimensions" || str == "\\$unpacked_dimensions" ||
+			    str == "\\$increment" || str == "\\$size" || str == "\\$bits" || str == "\\$high" || str == "\\$low" || str == "\\$left" || str == "\\$right")
 			{
 				int dim = 1;
-				if (str == "\\$bits") {
+				if (str == "\\$dimensions" || str == "\\$unpacked_dimensions" || str == "\\$bits") {
 					if (children.size() != 1)
 						input_error("System function %s got %d arguments, expected 1.\n",
 								RTLIL::unescape_id(str).c_str(), int(children.size()));
@@ -3509,6 +3510,7 @@ skip_dynamic_range_lvalue_expansion:;
 				AstNode *buf = children[0]->clone();
 				int mem_depth = 1;
 				int result, high = 0, low = 0, left = 0, right = 0, width = 1; // defaults for a simple wire
+				int expr_dimensions = 0, expr_unpacked_dimensions = 0;
 				AstNode *id_ast = NULL;
 
 				buf->detectSignWidth(width_hint, sign_hint);
@@ -3534,6 +3536,10 @@ skip_dynamic_range_lvalue_expansion:;
 						// or if the second argument is out of range, then 'x shall be returned."
 						if (dim < 1 || dim > dims)
 							input_error("Dimension %d out of range in `%s', as it only has %d dimensions!\n", dim, id_ast->str.c_str(), dims);
+
+						expr_dimensions = dims - dim + 1;
+						expr_unpacked_dimensions = std::max(id_ast->unpacked_dimensions - dim + 1, 0);
+
 						right = low  = id_ast->dimensions[dim - 1].range_right;
 						left  = high = low + id_ast->dimensions[dim - 1].range_width - 1;
 						if (id_ast->dimensions[dim - 1].range_swapped) {
@@ -3546,9 +3552,16 @@ skip_dynamic_range_lvalue_expansion:;
 					width = high - low + 1;
 				} else {
 					width = width_hint;
+					right = low  = 0;
+					left  = high = width - 1;
+					expr_dimensions = 1;
 				}
 				delete buf;
-				if (str == "\\$high")
+				if (str == "\\$dimensions")
+					result = expr_dimensions;
+				else if (str == "\\$unpacked_dimensions")
+					result = expr_unpacked_dimensions;
+				else if (str == "\\$high")
 					result = high;
 				else if (str == "\\$low")
 					result = low;
diff --git a/tests/sat/sizebits.sv b/tests/sat/sizebits.sv
index a31cae78c..a28f7ebb2 100644
--- a/tests/sat/sizebits.sv
+++ b/tests/sat/sizebits.sv
@@ -10,6 +10,24 @@ wire [3:0]z[7:2][2:9];
 //wire [$size(y)-1:0]y_size;
 //wire [$size(z)-1:0]z_size;
 
+assert property ($dimensions(t) == 1);
+assert property ($dimensions(x) == 1);
+assert property ($dimensions({3{x}}) == 1);
+assert property ($dimensions(y) == 2);
+assert property ($dimensions(y[2]) == 1);
+assert property ($dimensions(z) == 3);
+assert property ($dimensions(z[3]) == 2);
+assert property ($dimensions(z[3][3]) == 1);
+
+assert property ($unpacked_dimensions(t) == 0);
+assert property ($unpacked_dimensions(x) == 0);
+assert property ($unpacked_dimensions({3{x}}) == 0);
+assert property ($unpacked_dimensions(y) == 1);
+assert property ($unpacked_dimensions(y[2]) == 0);
+assert property ($unpacked_dimensions(z) == 2);
+assert property ($unpacked_dimensions(z[3]) == 1);
+assert property ($unpacked_dimensions(z[3][3]) == 0);
+
 assert property ($size(t) == 1);
 assert property ($size(x) == 4);
 assert property ($size({3{x}}) == 3*4);
diff --git a/tests/svtypes/struct_sizebits.sv b/tests/svtypes/struct_sizebits.sv
index 7f33fe72c..0a94d57a5 100644
--- a/tests/svtypes/struct_sizebits.sv
+++ b/tests/svtypes/struct_sizebits.sv
@@ -25,6 +25,18 @@ struct packed {
 //wire [$bits({s.x, s.x})-1:0]xx_bits;
 
 always_comb begin
+	assert ($dimensions(s) == 1);
+	assert ($dimensions(s.t) == 1);
+	assert ($dimensions(s.x) == 1);
+`ifndef VERIFIC
+	assert ($dimensions({3{s.x}}) == 1);
+`endif
+	assert ($dimensions(s.sy.y) == 2);
+	assert ($dimensions(s.sy.y[2]) == 1);
+	assert ($dimensions(s.sz.z) == 3);
+	assert ($dimensions(s.sz.z[3]) == 2);
+	assert ($dimensions(s.sz.z[3][3]) == 1);
+
 	assert ($size(s) == $size(s.t) + $size(s.x) + $size(s.sy) + $size(s.sz));
 	assert ($size(s) == 1 + 4 + 6*4 + 6*8*4);