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fixed some issues regarding goto handling

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This commit is contained in:
hyunghwan.chung 2019-08-06 10:01:54 +00:00
parent c299101781
commit 11b2629680
5 changed files with 184 additions and 151 deletions
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20
moo/README.md
View File

@ -117,20 +117,30 @@ ex resume.
ex resume: value.
ex return: value.
### return from context(method/block)
explicit return operators
```
^ return_stacktop
^^ local_return
```
implicit return when the end of the context is reached
* a method context returns the receiver.
* a block context returns the last evaluated value. if nothing has been evaluated, nil is returned.
### goto
```
goto jump_label.
jump_label:
a + b;
a + b.
```
useful to make a block return
can i deprecate the ^^ operator?
goto inside a block context.
```
[ 1 + 2. goto r. 3 + 4. r:]
[ 1 + 2. goto r. 3 + 4. r: 99 ]
```
goto must not cross the boundary of the block context.

45
moo/kernel/test-003.moo
View File

@ -52,6 +52,24 @@ class MyObject(Object)
].
}
method(#class) local_return_001
{
| a b c d|
a := 10.
c := 2.
d := 3.
b := ([
[
a := a + 3.
if (a > 10) { ^^77 } // ^^ must return to the calling method despite 2 blocks nested.
] value.
d := 99. // this is skipped because of ^^77 above.
] ensure: [ c := 88 ]). // however, the ensured block must be executed.
^a == 13 and b == 77 and c == 88 and d == 3.
}
method(#class) q
{
| v |
@ -90,11 +108,23 @@ start:
[([] isKindOf: MethodContext) == false],
[([] isKindOf: Context) == true],
// 15-20
// 15-19
[("string" isKindOf: String) == true],
[(#symbol isKindOf: String) == true],
[("string" isKindOf: Symbol) == false],
[(#symbol isKindOf: Symbol) == true]
[(#symbol isKindOf: Symbol) == true],
[ [] value == nil ],
// 20-24
[ self local_return_001 ],
[ (if (1 > 2) { } else { }) == nil. ],
[ (if (1 < 2) { } else { }) == nil. ],
[ (if (1 > 2) { } else { goto A01. A01: }) == nil ],
[ (if (1 > 2) { } else { 9876. goto A02. A02: }) == 9876 ],
// 25-29
[ [ | a3 | a3:= 20. if (a3 == 21) { a3 := 4321. goto L03 } else { a3 := 1234. goto L03 }. a3 := 8888. L03: a3 ] value == 1234 ],
[ [ | a4 | a4:= 21. if (a4 == 21) { a4 := 4321. goto L04 } else { a4 := 1234. goto L04 }. a4 := 8888. L04: a4 ] value == 4321 ]
).
limit := tc size.
@ -104,11 +134,16 @@ start:
tb := tc at: idx.
System log(System.Log.INFO, idx asString, (if (tb value) { " PASS" } else { " FAIL" }), "\n").
].
(if (true) { a: 10. b: 1p1000. c: 20000 }) dump.
[goto B02. A01: 10. B02: 1000. ] value class dump.
// (if (true) { a: 10. b: 1p1000. c: 20000 }) dump.
// [goto B02. A01: 10. B02: 1000. ] value class dump.
self q.
[ | a | a := 21. if (a = 21) { goto X02 }. X02: ] value dump. // this causes a stack depletion problem... TODO:
//[ | a | a := 21. if (a = 21) { goto X02 }. X02: ] value dump. // this causes a stack depletion problem... TODO:
//[ a := 4. while (1) { X44: goto X33 }. X33: 1233 dump. if (a < 10) { a := a + 1. 'X44' dump. goto X44 } else { 'ELSE' dump. a := a * 10}. ] value dump.
/*
this is horrible... the stack won't be cleared when goto is made...

262
moo/lib/comp.c
View File

@ -4911,132 +4911,6 @@ static int compile_block_expression (moo_t* moo)
if (emit_single_param_instruction(moo, BCODE_JUMP_FORWARD, MAX_CODE_JUMP, &block_loc) <= -1) return -1;
/* compile statements inside a block */
#if 0
if (TOKEN_TYPE(moo) == MOO_IOTOK_RBRACK)
{
/* the block is empty */
if (emit_byte_instruction(moo, BCODE_PUSH_NIL, TOKEN_LOC(moo)) <= -1) return -1;
}
else
{
int empty = 1, n;
while (TOKEN_TYPE(moo) != MOO_IOTOK_EOF)
{
n = compile_block_statement(moo);
if (n <= -1) return -1;
if (n == 8888)
{
/* compile_block_statement() processed non-statement item like a jump label. */
if (TOKEN_TYPE(moo) == MOO_IOTOK_RBRACK)
{
if (empty && emit_byte_instruction(moo, BCODE_PUSH_NIL, TOKEN_LOC(moo)) <= -1) return -1;
break;
}
}
else
{
/* a proper statement has been processed in compile_block_statemnt */
empty = 0;
if (TOKEN_TYPE(moo) == MOO_IOTOK_RBRACK) break;
else if (TOKEN_TYPE(moo) == MOO_IOTOK_PERIOD)
{
moo_ioloc_t period_loc = *TOKEN_LOC(moo);
GET_TOKEN (moo);
if (TOKEN_TYPE(moo) == MOO_IOTOK_RBRACK) break;
if (emit_byte_instruction(moo, BCODE_POP_STACKTOP, &period_loc) <= -1) return -1;
}
else
{
moo_setsynerr (moo, MOO_SYNERR_RBRACK, TOKEN_LOC(moo), TOKEN_NAME(moo));
return -1;
}
}
}
}
#elif 0
code_start = cc->mth.code.len;
if (TOKEN_TYPE(moo) != MOO_IOTOK_RBRACK)
{
moo_oow_t pop_stacktop_pos = 0;
do
{
int n;
if (TOKEN_TYPE(moo) == MOO_IOTOK_EOF)
{
moo_setsynerr (moo, MOO_SYNERR_RBRACK, TOKEN_LOC(moo), TOKEN_NAME(moo));
return -1;
}
n = compile_block_statement(moo);
if (n <= -1) return -1;
if (n == 8888)
{
/* compile_block_statement() processed non-statement item like a jump label. */
if (TOKEN_TYPE(moo) == MOO_IOTOK_RBRACK)
{
/* eliminate BCODE_POP_STACKTOP produced in the else block below
* becuase the non-steatemnt item is the last item before the closing bracket */
if (pop_stacktop_pos > 0) eliminate_instructions (moo, pop_stacktop_pos, cc->mth.code.len - 1);
break;
}
}
else if (n == 7777)
{
/* goto statement -
* the goto statement looks like a normal statement, but it never pushes a value.
* so no pop_stacktop instruction needs to get injected */
if (TOKEN_TYPE(moo) == MOO_IOTOK_RBRACK)
{
/* eliminate BCODE_POP_STACKTOP produced in the else block below
* because the non-steatemnt item is the last item before the closing bracket */
if (pop_stacktop_pos > 0) eliminate_instructions (moo, pop_stacktop_pos, cc->mth.code.len - 1);
break;
}
else if (TOKEN_TYPE(moo) == MOO_IOTOK_PERIOD)
{
GET_TOKEN (moo);
if (TOKEN_TYPE(moo) == MOO_IOTOK_RBRACK) break;
}
else
{
moo_setsynerr (moo, MOO_SYNERR_RBRACK, TOKEN_LOC(moo), TOKEN_NAME(moo));
return -1;
}
}
else
{
/* a proper statement has been processed in compile_block_statemnt */
if (TOKEN_TYPE(moo) == MOO_IOTOK_RBRACK) break;
else if (TOKEN_TYPE(moo) == MOO_IOTOK_PERIOD)
{
moo_ioloc_t period_loc = *TOKEN_LOC(moo);
GET_TOKEN (moo);
if (TOKEN_TYPE(moo) == MOO_IOTOK_RBRACK) break;
pop_stacktop_pos = cc->mth.code.len;
if (emit_byte_instruction(moo, BCODE_POP_STACKTOP, &period_loc) <= -1) return -1;
}
else
{
moo_setsynerr (moo, MOO_SYNERR_RBRACK, TOKEN_LOC(moo), TOKEN_NAME(moo));
return -1;
}
}
}
while (1);
}
if (cc->mth.code.len == code_start)
{
/* the block is empty */
if (emit_byte_instruction(moo, BCODE_PUSH_NIL, TOKEN_LOC(moo)) <= -1) return -1;
}
#else
code_start = cc->mth.code.len;
if (emit_byte_instruction(moo, BCODE_PUSH_NIL, TOKEN_LOC(moo)) <= -1) return -1;
@ -5130,19 +5004,16 @@ static int compile_block_expression (moo_t* moo)
}
}
while (1);
}
/*
if (cc->mth.code.len > 2 && cc->mth.code.len - 2 == code_start)
{
if (cc->mth.code.ptr[code_start] == BCODE_PUSH_NIL &&
cc->mth.code.ptr[code_start + 1] == BCODE_POP_STACKTOP &&
no goto found... <--- it's a bit tricy since goto can be inside other expressions like 'if' expression.
MOO_ASSERT (moo, cc->mth.code.len > code_start);
if (cc->mth.code.len - code_start >= 2 &&
cc->mth.code.ptr[code_start] == BCODE_PUSH_NIL &&
cc->mth.code.ptr[code_start + 1] == BCODE_POP_STACKTOP)
{
eliminate_instructions(moo, code_start, code_start + 2);
/* elminnate the block prologue */
eliminate_instructions(moo, code_start, code_start + 1);
}
}*/
#endif
}
if (emit_byte_instruction(moo, BCODE_RETURN_FROM_BLOCK, TOKEN_LOC(moo)) <= -1) return -1;
@ -6177,6 +6048,7 @@ static int compile_braced_block (moo_t* moo)
GET_TOKEN (moo);
#if 0
code_start = cc->mth.code.len;
if (TOKEN_TYPE(moo) != MOO_IOTOK_RBRACE)
{
@ -6244,6 +6116,122 @@ static int compile_braced_block (moo_t* moo)
/* the block doesn't contain an instruction at all */
if (emit_byte_instruction(moo, BCODE_PUSH_NIL, TOKEN_LOC(moo)) <= -1) return -1;
}
#else
code_start = cc->mth.code.len;
if (emit_byte_instruction(moo, BCODE_PUSH_NIL, TOKEN_LOC(moo)) <= -1) return -1;
if (TOKEN_TYPE(moo) != MOO_IOTOK_RBRACE)
{
moo_oow_t pop_stacktop_pos;
pop_stacktop_pos = cc->mth.code.len;
if (emit_byte_instruction(moo, BCODE_POP_STACKTOP, TOKEN_LOC(moo)) <= -1) return -1;
do
{
int n;
if (TOKEN_TYPE(moo) == MOO_IOTOK_EOF)
{
moo_setsynerr (moo, MOO_SYNERR_RBRACE, TOKEN_LOC(moo), TOKEN_NAME(moo));
return -1;
}
n = compile_block_statement(moo);
if (n <= -1) return -1;
if (n == 8888)
{
/* compile_block_statement() processed non-statement item like a jump label. */
MOO_ASSERT (moo, cc->mth._label != MOO_NULL);
if (TOKEN_TYPE(moo) == MOO_IOTOK_RBRACE)
{
#if 0
/* the last label inside {} must be followed by a valid statement */
moo_oocs_t labname;
labname.ptr = (moo_ooch_t*)(cc->mth._label + 1);
labname.len = moo_count_oocstr(labname.ptr);
moo_setsynerrbfmt (moo, MOO_SYNERR_LABELATEND, &cc->mth._label->loc, &labname, "label at end of braced block");
return -1;
#else
/* unlike in [], a label can be placed at the back of the block.
* to keep the last evaluated value, eliminate the pop_stacktop instruction */
if (pop_stacktop_pos > 0) eliminate_instructions (moo, pop_stacktop_pos, pop_stacktop_pos);
break;
#endif
}
}
else if (n == 7777)
{
/* goto statement */
if (TOKEN_TYPE(moo) == MOO_IOTOK_RBRACE)
{
/* jumping somewhere inside {} is different from inside [].
* [] needs to leave a return value when leaving the block.
* {} doesn't need to because {} can only be used as part of 'if', 'while', 'until', 'do'.
* that means, the last evaluated value inside {} before exit is used
* as a lvalue but the jump target can't be break into an assignment statement.
*
* a : 3.
* a := if (1) { goto L30 }. // if jump to L30 is made inside {}, assignment to 'a' is skipped.
* // so the evaluation result of the 'if' statement goes unused.
* L30: b := a + 1. // therefore, 'a' holds 3.
*
* it is not allowed to place label inside "b := a + 1".
* so the pop_stacktop produced must not be eliminated.
*/
break;
}
else if (TOKEN_TYPE(moo) == MOO_IOTOK_PERIOD)
{
GET_TOKEN (moo);
if (TOKEN_TYPE(moo) == MOO_IOTOK_RBRACE) break;
}
else
{
moo_setsynerr (moo, MOO_SYNERR_RBRACE, TOKEN_LOC(moo), TOKEN_NAME(moo));
return -1;
}
}
else
{
pop_stacktop_pos = cc->mth.code.len; /* remember the position of the last POP_STACKTOP for elimination */
if (emit_byte_instruction(moo, BCODE_POP_STACKTOP, TOKEN_LOC(moo)) <= -1) return -1;
if (TOKEN_TYPE(moo) == MOO_IOTOK_RBRACE)
{
eliminate_instructions (moo, pop_stacktop_pos, pop_stacktop_pos);
pop_stacktop_pos = INVALID_IP;
break;
}
else if (TOKEN_TYPE(moo) == MOO_IOTOK_PERIOD)
{
GET_TOKEN (moo);
if (TOKEN_TYPE(moo) == MOO_IOTOK_RBRACE)
{
eliminate_instructions(moo, pop_stacktop_pos, pop_stacktop_pos);
pop_stacktop_pos = INVALID_IP;
break;
}
}
else
{
moo_setsynerr (moo, MOO_SYNERR_RBRACE, TOKEN_LOC(moo), TOKEN_NAME(moo));
return -1;
}
}
}
while (1);
MOO_ASSERT (moo, cc->mth.code.len > code_start);
if (cc->mth.code.len - code_start >= 2 &&
cc->mth.code.ptr[code_start] == BCODE_PUSH_NIL &&
cc->mth.code.ptr[code_start + 1] == BCODE_POP_STACKTOP)
{
/* elminnate the block prologue */
eliminate_instructions(moo, code_start, code_start + 1);
}
}
#endif
if (TOKEN_TYPE(moo) != MOO_IOTOK_RBRACE)
{
@ -7123,7 +7111,7 @@ static int compile_method_statements (moo_t* moo)
}
else
{
/* a proper statement has been processed */
/* a proper statement or a goto statement(if n == 7777) has been processed */
if (TOKEN_TYPE(moo) == MOO_IOTOK_PERIOD)
{
/* period after a statement */

5
moo/lib/exec.c
View File

@ -5102,8 +5102,6 @@ static MOO_INLINE int do_return (moo_t* moo, moo_oob_t bcode, moo_oop_t return_v
static MOO_INLINE void do_return_from_block (moo_t* moo)
{
LOG_INST0 (moo, "return_from_block");
MOO_ASSERT (moo, MOO_CLASSOF(moo, moo->active_context) == moo->_block_context);
if (moo->active_context == moo->processor->active->initial_context)
@ -5974,7 +5972,7 @@ static int __execute (moo_t* moo)
handle_return:
{
int n;
if ((n = do_return (moo, bcode, return_value)) <= -1) return -1;
if ((n = do_return(moo, bcode, return_value)) <= -1) return -1;
if (n == 0) EXIT_DISPATCH_LOOP();
}
NEXT_INST();
@ -5986,6 +5984,7 @@ static int __execute (moo_t* moo)
goto handle_return;
ON_INST(BCODE_RETURN_FROM_BLOCK)
LOG_INST0 (moo, "return_from_block");
do_return_from_block (moo);
NEXT_INST();

3
moo/lib/moo-cmn.h
View File

@ -1046,5 +1046,6 @@ typedef struct moo_t moo_t;
# define MOO_STATIC_ASSERT(expr) typedef char MOO_STATIC_JOIN(MOO_STATIC_ASSERT_T_, __LINE__)[(expr)? 1: -1] MOO_UNUSED
#endif
#define MOO_STATIC_ASSERT_EXPR(expr) ((void)MOO_SIZEOF(char[(expr)? 1: -1]))
#define MOO_STATIC_ASSERT_EXPR(expr) ((void)MOO_SIZEOF(char[(expr)? 1: -1]))
#endif