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sv: support declaration in procedural for initialization

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In line with other tools, this adds an extra wrapping block around such
for loops to appropriately scope the variable.
This commit is contained in:
Zachary Snow 2021-08-30 11:35:36 -06:00 • committed by Zachary Snow
parent 1dbf91a8ef
commit f0a52e3dd2
5 changed files with 104 additions and 1 deletions
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49
frontends/verilog/verilog_parser.y
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@ -2607,6 +2607,53 @@ asgn_binop:
TOK_SSHL_ASSIGN { $$ = AST_SHIFT_SLEFT; } |
TOK_SSHR_ASSIGN { $$ = AST_SHIFT_SRIGHT; } ;
for_initialization:
TOK_ID '=' expr {
AstNode *ident = new AstNode(AST_IDENTIFIER);
ident->str = *$1;
AstNode *node = new AstNode(AST_ASSIGN_EQ, ident, $3);
ast_stack.back()->children.push_back(node);
SET_AST_NODE_LOC(node, @1, @3);
} |
non_io_wire_type range TOK_ID {
frontend_verilog_yyerror("For loop variable declaration is missing initialization!");
} |
non_io_wire_type range TOK_ID '=' expr {
if (!sv_mode)
frontend_verilog_yyerror("For loop inline variable declaration is only supported in SystemVerilog mode!");
// loop variable declaration
AstNode *wire = $1;
AstNode *range = checkRange(wire, $2);
if (range != nullptr)
wire->children.push_back(range);
SET_AST_NODE_LOC(wire, @1, @3);
SET_AST_NODE_LOC(range, @2, @2);
AstNode *ident = new AstNode(AST_IDENTIFIER);
ident->str = *$3;
wire->str = *$3;
delete $3;
AstNode *loop = ast_stack.back();
AstNode *parent = ast_stack.at(ast_stack.size() - 2);
log_assert(parent->children.back() == loop);
// loop variable initialization
AstNode *asgn = new AstNode(AST_ASSIGN_EQ, ident, $5);
loop->children.push_back(asgn);
SET_AST_NODE_LOC(asgn, @3, @5);
SET_AST_NODE_LOC(ident, @3, @3);
// inject a wrapping block to declare the loop variable and
// contain the current loop
AstNode *wrapper = new AstNode(AST_BLOCK);
wrapper->str = "$fordecl_block$" + std::to_string(autoidx++);
wrapper->children.push_back(wire);
wrapper->children.push_back(loop);
parent->children.back() = wrapper; // replaces `loop`
};
// this production creates the obligatory if-else shift/reduce conflict
behavioral_stmt:
defattr | assert | wire_decl | param_decl | localparam_decl | typedef_decl |
@ -2667,7 +2714,7 @@ behavioral_stmt:
ast_stack.back()->children.push_back(node);
ast_stack.push_back(node);
append_attr(node, $1);
} simple_behavioral_stmt ';' expr {
} for_initialization ';' expr {
ast_stack.back()->children.push_back($7);
} ';' simple_behavioral_stmt ')' {
AstNode *block = new AstNode(AST_BLOCK);