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Allow only one return

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This commit is contained in:
Eugen Wissner
2025-03-01 00:00:36 +01:00
parent f091344cce
commit 18602d00a1
10 changed files with 39 additions and 198 deletions
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62
boot/ast.cc
View File

@@ -86,24 +86,6 @@ namespace boot
}
}
void empty_visitor::visit(return_statement *statement)
{
expression *return_expression = statement->return_expression();
if (return_expression != nullptr)
{
return_expression->accept(this);
}
}
void empty_visitor::visit(defer_statement *defer)
{
for (statement *const body_statement : defer->statements)
{
body_statement->accept(this);
}
}
void empty_visitor::visit(block *block)
{
for (constant_definition *const constant : block->constants)
@@ -448,8 +430,9 @@ namespace boot
}
procedure_definition::procedure_definition(const struct position position, const std::string& identifier,
const bool exported, std::shared_ptr<procedure_type> heading, block *body)
: definition(position, identifier, exported), m_heading(heading), body(body)
const bool exported, std::shared_ptr<procedure_type> heading,
block *const body, expression *const returning)
: definition(position, identifier, exported), m_heading(heading), body(body), returning(returning)
{
}
@@ -466,6 +449,7 @@ namespace boot
procedure_definition::~procedure_definition()
{
delete body;
delete returning;
}
type_definition::type_definition(const struct position position, const std::string& identifier,
@@ -536,24 +520,6 @@ namespace boot
{
}
defer_statement::defer_statement(const struct position position)
: node(position)
{
}
void defer_statement::accept(parser_visitor *visitor)
{
visitor->visit(this);
}
defer_statement::~defer_statement()
{
for (statement *body_statement : statements)
{
delete body_statement;
}
}
designator_expression::designator_expression()
{
}
@@ -805,26 +771,6 @@ namespace boot
}
}
return_statement::return_statement(const struct position position, expression *return_expression)
: node(position), m_return_expression(return_expression)
{
}
void return_statement::accept(parser_visitor *visitor)
{
visitor->visit(this);
}
expression *return_statement::return_expression()
{
return m_return_expression;
}
return_statement::~return_statement()
{
delete m_return_expression;
}
void assign_statement::accept(parser_visitor *visitor)
{
visitor->visit(this);

3
boot/lexer.ll
View File

@@ -125,9 +125,6 @@ return {
cast {
return yy::parser::make_CAST(this->location);
}
defer {
return yy::parser::make_DEFER(this->location);
}
[A-Za-z_][A-Za-z0-9_]* {
return yy::parser::make_IDENTIFIER(yytext, this->location);
}

55
boot/parser.yy
View File

@@ -106,7 +106,6 @@ along with GCC; see the file COPYING3. If not see
RETURN "return"
BEGIN_BLOCK "begin"
END_BLOCK "end"
DEFER "defer"
%token OR "or" AND "and" XOR "xor"
EQUALS "=" NOT_EQUAL "<>" LESS_THAN "<" GREATER_THAN ">" LESS_EQUAL "<=" GREATER_EQUAL ">="
SHIFT_LEFT "<<" SHIFT_RIGHT ">>"
@@ -134,12 +133,12 @@ along with GCC; see the file COPYING3. If not see
%type <elna::boot::procedure_call*> call_expression;
%type <elna::boot::while_statement *> while_statement;
%type <elna::boot::if_statement *> if_statement;
%type <elna::boot::return_statement *> return_statement;
%type <elna::boot::expression *> return_statement;
%type <elna::boot::statement *> statement;
%type <std::vector<elna::boot::statement *>> statements optional_statements;
%type <std::vector<elna::boot::statement *>> statements statement_part;
%type <elna::boot::procedure_definition *> procedure_definition;
%type <std::shared_ptr<elna::boot::procedure_type>> procedure_heading;
%type <std::vector<elna::boot::procedure_definition *>> procedure_definitions procedure_part;
%type <std::vector<elna::boot::procedure_definition *>> procedure_definitions;
%type <elna::boot::type_definition *> type_definition;
%type <std::vector<elna::boot::type_definition *>> type_definitions type_part;
%type <elna::boot::block *> block;
@@ -147,12 +146,11 @@ along with GCC; see the file COPYING3. If not see
%type <std::vector<std::pair<std::string, std::shared_ptr<elna::boot::top_type>>>> optional_fields fields;
%type <std::vector<elna::boot::conditional_statements *>> elsif_then_statements elsif_do_statements;
%type <elna::boot::cast_expression *> cast_expression;
%type <elna::boot::defer_statement *> defer_statement;
%type <std::pair<std::string, bool>> identifier_definition;
%type <std::vector<std::pair<std::string, bool>>> identifier_definitions;
%%
program:
constant_part type_part variable_part procedure_part "begin" optional_statements "end" "."
constant_part type_part variable_part procedure_definitions "begin" statements "end" "."
{
auto tree = new elna::boot::program(elna::boot::make_position(@5));
@@ -164,13 +162,13 @@ program:
driver.tree.reset(tree);
}
block: constant_part variable_part "begin" optional_statements "end"
block: constant_part variable_part statement_part
{
$$ = new elna::boot::block(elna::boot::make_position(@3));
$$ = new elna::boot::block(elna::boot::make_position(@1));
std::swap($$->constants, $1);
std::swap($$->variables, $2);
std::swap($$->body, $4);
std::swap($$->body, $3);
}
identifier_definition:
IDENTIFIER "*"
@@ -205,9 +203,10 @@ procedure_heading:
std::swap($1, $$->parameters);
}
procedure_definition:
"proc" identifier_definition procedure_heading ";" block
"proc" identifier_definition procedure_heading ";" block return_statement "end"
{
$$ = new elna::boot::procedure_definition(elna::boot::make_position(@1), $2.first, $2.second, $3, $5);
$$ = new elna::boot::procedure_definition(elna::boot::make_position(@1), $2.first, $2.second,
$3, $5, $6);
}
| "proc" identifier_definition procedure_heading ";" "extern"
{
@@ -219,10 +218,7 @@ procedure_definitions:
std::swap($$, $2);
$$.emplace($$.cbegin(), std::move($1));
}
| procedure_definition { $$.emplace_back(std::move($1)); }
procedure_part:
/* no procedure definitions */ {}
| procedure_definitions { std::swap($$, $1); }
| /* no procedure definitions */ {}
assign_statement: designator_expression ":=" expression
{
$$ = new elna::boot::assign_statement(elna::boot::make_position(@1), $1, $3);
@@ -237,7 +233,7 @@ cast_expression: "cast" "(" expression ":" type_expression ")"
$$ = new elna::boot::cast_expression(elna::boot::make_position(@1), $5, $3);
}
elsif_do_statements:
"elsif" expression "do" optional_statements elsif_do_statements
"elsif" expression "do" statements elsif_do_statements
{
elna::boot::conditional_statements *branch = new elna::boot::conditional_statements($2);
std::swap(branch->statements, $4);
@@ -245,7 +241,7 @@ elsif_do_statements:
$$.emplace($$.begin(), branch);
}
| {}
while_statement: "while" expression "do" optional_statements elsif_do_statements "end"
while_statement: "while" expression "do" statements elsif_do_statements "end"
{
auto body = new elna::boot::conditional_statements($2);
std::swap($4, body->statements);
@@ -253,7 +249,7 @@ while_statement: "while" expression "do" optional_statements elsif_do_statements
std::swap($5, $$->branches);
}
elsif_then_statements:
"elsif" expression "then" optional_statements elsif_then_statements
"elsif" expression "then" statements elsif_then_statements
{
elna::boot::conditional_statements *branch = new elna::boot::conditional_statements($2);
std::swap(branch->statements, $4);
@@ -262,14 +258,14 @@ elsif_then_statements:
}
| {}
if_statement:
"if" expression "then" optional_statements elsif_then_statements "end"
"if" expression "then" statements elsif_then_statements "end"
{
auto then = new elna::boot::conditional_statements($2);
std::swap($4, then->statements);
$$ = new elna::boot::if_statement(elna::boot::make_position(@1), then);
std::swap($5, $$->branches);
}
| "if" expression "then" optional_statements elsif_then_statements "else" optional_statements "end"
| "if" expression "then" statements elsif_then_statements "else" statements "end"
{
auto then = new elna::boot::conditional_statements($2);
std::swap($4, then->statements);
@@ -277,15 +273,12 @@ if_statement:
$$ = new elna::boot::if_statement(elna::boot::make_position(@1), then, _else);
std::swap($5, $$->branches);
}
return_statement: "return" expression
return_statement:
"return" expression
{
$$ = new elna::boot::return_statement(elna::boot::make_position(@1), $2);
}
defer_statement: DEFER optional_statements "end"
{
$$ = new elna::boot::defer_statement(elna::boot::make_position(@1));
std::swap($2, $$->statements);
$$ = $2;
}
| /* no return statement */ { $$ = nullptr; }
literal:
INTEGER
{
@@ -454,19 +447,17 @@ statement:
assign_statement { $$ = $1; }
| while_statement { $$ = $1; }
| if_statement { $$ = $1; }
| return_statement { $$ = $1; }
| call_expression { $$ = $1; }
| defer_statement { $$ = $1; }
statements:
statement statements
{
std::swap($$, $2);
$$.emplace($$.cbegin(), $1);
}
| statement { $$.push_back($1); }
optional_statements:
statements { std::swap($$, $1); }
| /* no statements */ {}
statement_part:
"begin" statements { std::swap($$, $2); }
| {}
field_declaration:
IDENTIFIER ":" type_expression { $$ = std::make_pair($1, $3); }
fields:

14
gcc/elna-generic.cc
View File

@@ -294,6 +294,7 @@ namespace gcc
if (definition->body != nullptr)
{
definition->body->accept(this);
visit_return(definition->returning);
tree mapping = leave_scope();
BLOCK_SUPERCONTEXT(BIND_EXPR_BLOCK(mapping)) = fndecl;
@@ -334,7 +335,7 @@ namespace gcc
{
BLOCK_SUPERCONTEXT(it) = new_block;
}
tree bind_expr = build3(BIND_EXPR, void_type_node, variables, chain_defer(), new_block);
tree bind_expr = build3(BIND_EXPR, void_type_node, variables, f_binding_level->statement_list, new_block);
this->symbol_map = this->symbol_map->scope();
f_binding_level = f_binding_level->level_chain;
@@ -1174,10 +1175,8 @@ namespace gcc
}
}
void generic_visitor::visit(boot::return_statement *statement)
void generic_visitor::visit_return(boot::expression *const return_expression)
{
boot::expression *return_expression = statement->return_expression();
if (return_expression == nullptr)
{
return;
@@ -1191,12 +1190,5 @@ namespace gcc
this->current_expression = NULL_TREE;
}
void generic_visitor::visit(boot::defer_statement *statement)
{
enter_scope();
visit_statements(statement->statements);
defer(leave_scope());
}
}
}

35
gcc/elna-tree.cc
View File

@@ -91,40 +91,7 @@ namespace gcc
void append_statement(tree statement_tree)
{
if (!vec_safe_is_empty(f_binding_level->defers))
{
append_to_statement_list(statement_tree, &f_binding_level->defers->begin()->try_statements);
}
else
{
append_to_statement_list(statement_tree, &f_binding_level->statement_list);
}
}
void defer(tree statement_tree)
{
defer_scope new_defer{ statement_tree, alloc_stmt_list() };
vec_safe_insert(f_binding_level->defers, 0, new_defer);
}
tree chain_defer()
{
if (vec_safe_is_empty(f_binding_level->defers))
{
return f_binding_level->statement_list;
}
defer_scope *defer_iterator = f_binding_level->defers->begin();
tree defer_tree = build2(TRY_FINALLY_EXPR, void_type_node,
defer_iterator->try_statements, defer_iterator->defer_block);
int i;
FOR_EACH_VEC_ELT_FROM(*f_binding_level->defers, i, defer_iterator, 1)
{
append_to_statement_list(defer_tree, &defer_iterator->try_statements);
defer_tree = build2(TRY_FINALLY_EXPR, void_type_node,
defer_iterator->try_statements, defer_iterator->defer_block);
}
return build2(COMPOUND_EXPR, TREE_TYPE(defer_tree), f_binding_level->statement_list, defer_tree);
append_to_statement_list(statement_tree, &f_binding_level->statement_list);
}
tree build_field(location_t location, tree record_type, const std::string name, tree type)

34
include/elna/boot/ast.h
View File

@@ -63,7 +63,6 @@ namespace boot
class assign_statement;
class if_statement;
class while_statement;
class return_statement;
class traits_expression;
class block;
class program;
@@ -81,7 +80,6 @@ namespace boot
class dereference_expression;
template<typename T>
class number_literal;
class defer_statement;
/**
* Interface for AST visitors.
@@ -98,8 +96,6 @@ namespace boot
virtual void visit(assign_statement *) = 0;
virtual void visit(if_statement *) = 0;
virtual void visit(while_statement *) = 0;
virtual void visit(return_statement *) = 0;
virtual void visit(defer_statement *) = 0;
virtual void visit(block *) = 0;
virtual void visit(program *) = 0;
virtual void visit(binary_expression *) = 0;
@@ -138,8 +134,6 @@ namespace boot
virtual void visit(assign_statement *statement) override;
virtual void visit(if_statement *) override;
virtual void visit(while_statement *) override;
virtual void visit(return_statement *) override;
virtual void visit(defer_statement *defer) override;
virtual void visit(block *block) override;
virtual void visit(program *program) override;
virtual void visit(binary_expression *expression) override;
@@ -383,9 +377,11 @@ namespace boot
public:
block *const body;
expression *const returning;
procedure_definition(const struct position position, const std::string& identifier,
const bool exported, std::shared_ptr<procedure_type> heading, block *body = nullptr);
const bool exported, std::shared_ptr<procedure_type> heading,
block *const body = nullptr, expression *const returning = nullptr);
virtual void accept(parser_visitor *visitor) override;
procedure_type& heading();
@@ -456,19 +452,6 @@ namespace boot
virtual ~conditional_statements();
};
class return_statement : public statement
{
expression *m_return_expression{ nullptr };
public:
return_statement(const struct position position, expression *return_expression);
virtual void accept(parser_visitor *visitor) override;
expression *return_expression();
virtual ~return_statement() override;
};
class designator_expression : public expression
{
public:
@@ -661,17 +644,6 @@ namespace boot
}
};
class defer_statement : public statement
{
public:
std::vector<statement *> statements;
defer_statement(const struct position position);
virtual void accept(parser_visitor *visitor) override;
virtual ~defer_statement() override;
};
class binary_expression : public expression
{
expression *m_lhs;

3
include/elna/gcc/elna-generic.h
View File

@@ -61,6 +61,7 @@ namespace gcc
void build_record_call(location_t call_location,
tree symbol, const std::vector<boot::expression *>& arguments);
void visit_statements(const std::vector<boot::statement *>& statements);
void visit_return(boot::expression *const return_expression);
public:
generic_visitor(std::shared_ptr<symbol_table> symbol_table);
@@ -90,8 +91,6 @@ namespace gcc
void visit(boot::assign_statement *statement) override;
void visit(boot::if_statement *statement) override;
void visit(boot::while_statement *statement) override;
void visit(boot::return_statement *statement) override;
void visit(boot::defer_statement *statement) override;
};
}
}

2
include/elna/gcc/elna-tree.h
View File

@@ -72,8 +72,6 @@ namespace gcc
bool is_assignable_from(tree assignee, tree assignment);
void append_statement(tree statement_tree);
void defer(tree statement_tree);
tree chain_defer();
tree do_pointer_arithmetic(boot::binary_operator binary_operator, tree left, tree right);
tree build_binary_operation(bool condition, boot::binary_expression *expression,

9
include/elna/gcc/elna1.h
View File

@@ -58,12 +58,6 @@ struct GTY (()) lang_decl
{
};
struct GTY (()) defer_scope
{
tree defer_block;
tree try_statements;
};
struct GTY ((chain_next ("%h.level_chain"))) binding_level
{
// A block chain is needed to call defer statements beloning to each block.
@@ -74,9 +68,6 @@ struct GTY ((chain_next ("%h.level_chain"))) binding_level
// Statements before the first defer has been seen.
tree statement_list;
// Defer statement coupled with statements following it.
vec<defer_scope, va_gc> *defers;
};
struct GTY (()) language_function

20
source.elna
View File

@@ -140,7 +140,6 @@ proc exit(code: Int) -> !; extern
Standard procedures.
*)
proc reallocarray(ptr: ^Byte, n: Word, size: Word) -> ^Byte;
begin
return realloc(ptr, n * size)
end
@@ -198,32 +197,26 @@ begin
end
proc is_digit(c: Char) -> Bool;
begin
return cast(c: Int) >= cast('0': Int) and cast(c: Int) <= cast('9': Int)
end
proc is_alpha(c: Char) -> Bool;
begin
return cast(c: Int) >= cast('A': Int) and cast(c: Int) <= cast('z': Int)
end
proc is_alnum(c: Char) -> Bool;
begin
return is_digit(c) or is_alpha(c)
end
proc is_space(c: Char) -> Bool;
begin
return c = ' ' or c = '\n' or c = '\t'
end
proc substring(string: String, start: Word, count: Word) -> String;
begin
return String(string.ptr + start, count)
end
proc open_substring(string: String, start: Word) -> String;
begin
return substring(string, start, string.length - start)
end
@@ -277,7 +270,6 @@ end
*)
proc make_position() -> Position;
begin
return Position(1u, 1u)
end
@@ -376,12 +368,10 @@ begin
end
proc source_code_empty(source_code: ^SourceCode) -> Bool;
begin
return source_code^.empty(source_code^.input)
end
proc source_code_head(source_code: SourceCode) -> Char;
begin
return source_code.head(source_code.input)
end
@@ -398,7 +388,6 @@ begin
end
proc source_code_expect(source_code: ^SourceCode, expected: Char) -> Bool;
begin
return not source_code_empty(source_code) and source_code_head(source_code^) = expected
end
@@ -413,7 +402,6 @@ begin
end
proc is_ident(char: Char) -> Bool;
begin
return is_alnum(char) or char = '_'
end
@@ -916,7 +904,7 @@ begin
result^.syntax_tree := false
result^.input := nil
while i < argc do
while i < argc and result <> nil do
parameter := argv + i
if strcmp(parameter^, "--tokenize\0".ptr) = 0 then
@@ -932,14 +920,14 @@ begin
write_z(parameter^)
write_s(".\n")
return nil
result := nil
end
i := i + 1
end
if result^.input = nil then
if result <> nil and result^.input = nil then
write_s("Fatal error: no input files.\n")
return nil
result := nil
end
return result