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Verilog: indexed part select expressions with non-constant index
This implements support for indexed part select expressions where the index is not an elaboration-time constant.
1 parent fbfde77 commit 8b19daf

15 files changed

+217
-70
lines changed

‎regression/verilog/part-select/index-of-real.desc

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CORE
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index-of-real.sv
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^file .* line 5: bit-select of real is not allowed$
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^EXIT=2$
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^SIGNAL=0$
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--
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^warning: ignoring

‎regression/verilog/part-select/index-of-real.sv

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module main;
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// 1800-2017 6.12.1
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real some_real;
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wire x = some_real[0];
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endmodule

‎regression/verilog/indexed-part-select1/test.desc renamed to ‎regression/verilog/part-select/indexed-part-select1.desc

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@@ -1,6 +1,6 @@
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CORE broken-smt-backend
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main.sv
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--bound 1
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indexed-part-select1.sv
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--bound 0
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^EXIT=0$
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^SIGNAL=0$
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--

‎regression/verilog/indexed-part-select1/main.sv renamed to ‎regression/verilog/part-select/indexed-part-select1.sv

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@@ -9,7 +9,6 @@ module main(in);
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out[16 +: 16]=0;
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end
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always assert property1:
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{ in, { 8 { 1'b0 }} } == out;
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p1: assert property ({ in, { 8 { 1'b0 }} } == out);
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endmodule

‎regression/verilog/part-select/indexed-part-select2.desc

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CORE
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indexed-part-select2.sv
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^file .* line 4: expected constant expression, but got `main\.width'$
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^EXIT=2$
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^SIGNAL=0$
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--
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^warning: ignoring

‎regression/verilog/part-select/indexed-part-select2.sv

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module main(input [7:0] in, input [2:0] width);
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// The width of an indexed part-select must be a constant
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wire [7:0] out = in[0 +: width];
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endmodule

‎regression/verilog/part-select/indexed-part-select3.desc

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CORE
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indexed-part-select3.sv
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--bound 0
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^EXIT=0$
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^SIGNAL=0$
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--
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^warning: ignoring
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--

‎regression/verilog/part-select/indexed-part-select3.sv

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module main(input [7:0] in, input [2:0] where);
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// The base index of an indexed part-select
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// does not need to be constant.
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wire out = in[where +: 1];
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p0: assert property (out == in[where]);
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endmodule

‎regression/verilog/part-select/part-select-of-real.desc

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CORE
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part-select-of-real.sv
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^file .* line 5: real not allowed in part select$
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^EXIT=2$
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^SIGNAL=0$
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--
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^warning: ignoring

‎regression/verilog/part-select/part-select-of-real.sv

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module main;
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// 1800-2017 6.12.1
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real some_real;
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wire [7:0] x = some_real[7:0];
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endmodule

‎regression/verilog/part-select/real-index.desc

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CORE
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real-index.sv
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^file .* line 5: real number index is not allowed$
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^EXIT=2$
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^SIGNAL=0$
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--
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^warning: ignoring

‎regression/verilog/part-select/real-index.sv

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module main;
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// 1800-2017 6.12.1
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reg [7:0] vector;
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wire x = vector[real'(1.5)];
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endmodule

‎src/hw_cbmc_irep_ids.h

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@@ -32,9 +32,9 @@ IREP_ID_TWO(C_little_endian, #little_endian)
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IREP_ID_ONE(ports)
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IREP_ID_ONE(inst)
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IREP_ID_ONE(Verilog)
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IREP_ID_ONE(part_select)
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IREP_ID_ONE(indexed_part_select_plus)
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IREP_ID_ONE(indexed_part_select_minus)
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IREP_ID_ONE(verilog_non_indexed_part_select)
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IREP_ID_ONE(verilog_indexed_part_select_plus)
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IREP_ID_ONE(verilog_indexed_part_select_minus)
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IREP_ID_ONE(chandle)
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IREP_ID_ONE(event)
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IREP_ID_ONE(reg)

‎src/verilog/parser.y

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Original file line numberDiff line numberDiff line change
@@ -148,47 +148,6 @@ static void extractbit(YYSTYPE &expr, YYSTYPE &identifier, YYSTYPE &part)
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/*******************************************************************\
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Function: extractbits
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Inputs:
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Outputs:
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Purpose:
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\*******************************************************************/
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static void extractbits(YYSTYPE &expr, YYSTYPE &identifier, YYSTYPE &range)
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{
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init(expr, ID_extractbits);
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mto(expr, identifier);
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if(stack_expr(range).id()==ID_part_select)
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{
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auto &part_select = to_binary_expr(stack_expr(range));
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stack_expr(expr).add_to_operands(std::move(part_select.op0()));
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stack_expr(expr).add_to_operands(std::move(part_select.op1()));
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}
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else if(stack_expr(range).id()==ID_indexed_part_select_plus)
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{
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auto &part_select = to_binary_expr(stack_expr(range));
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exprt offset=minus_exprt(part_select.op1(), from_integer(1, integer_typet{}));
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stack_expr(expr).add_to_operands(part_select.op0());
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stack_expr(expr).add_to_operands(plus_exprt(part_select.op0(), offset));
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}
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else if(stack_expr(range).id()==ID_indexed_part_select_minus)
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{
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auto &part_select = to_binary_expr(stack_expr(range));
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exprt offset=minus_exprt(from_integer(1, integer_typet{}), part_select.op1());
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stack_expr(expr).add_to_operands(part_select.op0());
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stack_expr(expr).add_to_operands(plus_exprt(part_select.op0(), offset));
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}
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else
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PRECONDITION(false);
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}
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/*******************************************************************\
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Function: add_as_subtype
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Inputs:
@@ -1145,7 +1104,7 @@ bit_select:
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part_select:
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'[' const_expression TOK_COLON const_expression ']'
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{ init($$, ID_part_select); mto($$, $2); mto($$, $4); }
1107+
{ init($$, ID_verilog_non_indexed_part_select); mto($$, $2); mto($$, $4); }
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;
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// System Verilog standard 1800-2017
@@ -3122,14 +3081,14 @@ inc_or_dec_expression:
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constant_range:
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const_expression TOK_COLON const_expression
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{ init($$, ID_part_select); mto($$, $1); mto($$, $3); }
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{ init($$, ID_verilog_non_indexed_part_select); mto($$, $1); mto($$, $3); }
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;
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indexed_range:
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expression TOK_PLUSCOLON constant_expression
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{ init($$, ID_indexed_part_select_plus); mto($$, $1); mto($$, $3); }
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{ init($$, ID_verilog_indexed_part_select_plus); mto($$, $1); mto($$, $3); }
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| expression TOK_MINUSCOLON constant_expression
3132-
{ init($$, ID_indexed_part_select_minus); mto($$, $1); mto($$, $3); }
3091+
{ init($$, ID_verilog_indexed_part_select_minus); mto($$, $1); mto($$, $3); }
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;
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31353094
part_select_range:
@@ -3161,7 +3120,13 @@ primary_literal:
31613120
hierarchical_identifier_select:
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hierarchical_identifier_bit_select_brace
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| hierarchical_identifier_bit_select_brace '[' part_select_range ']'
3164-
{ extractbits($$, $1, $3); }
3123+
{ // part_select_range has two operands.
3124+
// We form a new expression with three operands from it.
3125+
auto &part_select = to_binary_expr(stack_expr($3));
3126+
stack_expr($3).operands() =
3127+
{ stack_expr($1), part_select.op0(), part_select.op1() };
3128+
$$ = $3;
3129+
}
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;
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hierarchical_identifier_bit_select_brace:

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