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takikawatakikawa
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Allow plain try with no catch, etc.
Matches recent changes in the exception handling spec that allowed this case to reduce special cases in the syntax: WebAssembly/exception-handling#157
1 parent 9500425 commit 1ae0170

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10 files changed

+83
-74
lines changed

10 files changed

+83
-74
lines changed

‎src/binary-reader-ir.cc

+3-3
Original file line numberDiff line numberDiff line change
@@ -1012,7 +1012,7 @@ Result BinaryReaderIR::AppendCatch(Catch&& catch_) {
10121012
return Result::Error;
10131013
}
10141014

1015-
if (try_->kind == TryKind::Invalid) {
1015+
if (try_->kind == TryKind::Plain) {
10161016
try_->kind = TryKind::Catch;
10171017
} else if (try_->kind != TryKind::Catch) {
10181018
PrintError("catch not allowed in try-unwind or try-delegate");
@@ -1043,7 +1043,7 @@ Result BinaryReaderIR::OnUnwindExpr() {
10431043

10441044
auto* try_ = cast<TryExpr>(label->context);
10451045

1046-
if (try_->kind == TryKind::Invalid) {
1046+
if (try_->kind == TryKind::Plain) {
10471047
try_->kind = TryKind::Unwind;
10481048
} else if (try_->kind != TryKind::Unwind) {
10491049
PrintError("unwind not allowed in try-catch or try-delegate");
@@ -1065,7 +1065,7 @@ Result BinaryReaderIR::OnDelegateExpr(Index depth) {
10651065

10661066
auto* try_ = cast<TryExpr>(label->context);
10671067

1068-
if (try_->kind == TryKind::Invalid) {
1068+
if (try_->kind == TryKind::Plain) {
10691069
try_->kind = TryKind::Delegate;
10701070
} else if (try_->kind != TryKind::Delegate) {
10711071
PrintError("delegate not allowed in try-catch or try-unwind");

‎src/binary-writer.cc

+2-2
Original file line numberDiff line numberDiff line change
@@ -1017,8 +1017,8 @@ void BinaryWriter::WriteExpr(const Func* func, const Expr* expr) {
10171017
GetLabelVarDepth(&try_expr->delegate_target),
10181018
"delegate depth");
10191019
break;
1020-
case TryKind::Invalid:
1021-
// Should not occur.
1020+
case TryKind::Plain:
1021+
WriteOpcode(stream_, Opcode::End);
10221022
break;
10231023
}
10241024
break;

‎src/expr-visitor.cc

+2-2
Original file line numberDiff line numberDiff line change
@@ -114,8 +114,8 @@ Result ExprVisitor::VisitExpr(Expr* root_expr) {
114114
case TryKind::Delegate:
115115
CHECK_RESULT(delegate_->OnDelegateExpr(try_expr));
116116
break;
117-
case TryKind::Invalid:
118-
// Should not happen.
117+
case TryKind::Plain:
118+
CHECK_RESULT(delegate_->EndTryExpr(try_expr));
119119
break;
120120
}
121121
}

‎src/ir.h

+2-2
Original file line numberDiff line numberDiff line change
@@ -378,7 +378,7 @@ struct Catch {
378378
typedef std::vector<Catch> CatchVector;
379379

380380
enum class TryKind {
381-
Invalid,
381+
Plain,
382382
Catch,
383383
Unwind,
384384
Delegate
@@ -604,7 +604,7 @@ class IfExpr : public ExprMixin<ExprType::If> {
604604
class TryExpr : public ExprMixin<ExprType::Try> {
605605
public:
606606
explicit TryExpr(const Location& loc = Location())
607-
: ExprMixin<ExprType::Try>(loc), kind(TryKind::Invalid) {}
607+
: ExprMixin<ExprType::Try>(loc), kind(TryKind::Plain) {}
608608

609609
TryKind kind;
610610
Block block;

‎src/wast-parser.cc

+26-27
Original file line numberDiff line numberDiff line change
@@ -2601,8 +2601,6 @@ Result WastParser::ParseBlockInstr(std::unique_ptr<Expr>* out_expr) {
26012601
CHECK_RESULT(ParseVar(&var));
26022602
expr->delegate_target = var;
26032603
expr->kind = TryKind::Delegate;
2604-
} else {
2605-
return ErrorExpected({"catch", "catch_all", "unwind", "delegate"});
26062604
}
26072605
CHECK_RESULT(ErrorIfLpar({"a valid try clause"}));
26082606
expr->block.end_loc = GetLocation();
@@ -2771,32 +2769,33 @@ Result WastParser::ParseExpr(ExprList* exprs) {
27712769
EXPECT(Do);
27722770
CHECK_RESULT(ParseInstrList(&expr->block.exprs));
27732771
EXPECT(Rpar);
2774-
EXPECT(Lpar);
2775-
TokenType type = Peek();
2776-
switch (type) {
2777-
case TokenType::Catch:
2778-
case TokenType::CatchAll:
2779-
CHECK_RESULT(ParseCatchExprList(&expr->catches));
2780-
expr->kind = TryKind::Catch;
2781-
break;
2782-
case TokenType::Unwind:
2783-
Consume();
2784-
CHECK_RESULT(ParseTerminatingInstrList(&expr->unwind));
2785-
expr->kind = TryKind::Unwind;
2786-
EXPECT(Rpar);
2787-
break;
2788-
case TokenType::Delegate: {
2789-
Consume();
2790-
Var var;
2791-
CHECK_RESULT(ParseVar(&var));
2792-
expr->delegate_target = var;
2793-
expr->kind = TryKind::Delegate;
2794-
EXPECT(Rpar);
2795-
break;
2772+
if (PeekMatch(TokenType::Lpar)) {
2773+
Consume();
2774+
TokenType type = Peek();
2775+
switch (type) {
2776+
case TokenType::Catch:
2777+
case TokenType::CatchAll:
2778+
CHECK_RESULT(ParseCatchExprList(&expr->catches));
2779+
expr->kind = TryKind::Catch;
2780+
break;
2781+
case TokenType::Unwind:
2782+
Consume();
2783+
CHECK_RESULT(ParseTerminatingInstrList(&expr->unwind));
2784+
expr->kind = TryKind::Unwind;
2785+
EXPECT(Rpar);
2786+
break;
2787+
case TokenType::Delegate: {
2788+
Consume();
2789+
Var var;
2790+
CHECK_RESULT(ParseVar(&var));
2791+
expr->delegate_target = var;
2792+
expr->kind = TryKind::Delegate;
2793+
EXPECT(Rpar);
2794+
break;
2795+
}
2796+
default:
2797+
break;
27962798
}
2797-
default:
2798-
ErrorExpected({"catch", "catch_all", "unwind", "delegate"});
2799-
break;
28002799
}
28012800
CHECK_RESULT(ErrorIfLpar({"a valid try clause"}));
28022801
expr->block.end_loc = GetLocation();

‎src/wat-writer.cc

+2-2
Original file line numberDiff line numberDiff line change
@@ -1187,8 +1187,8 @@ void WatWriter::FlushExprTree(const ExprTree& expr_tree) {
11871187
WriteVar(try_expr->delegate_target, NextChar::None);
11881188
WritePuts(")", NextChar::Newline);
11891189
break;
1190-
case TryKind::Invalid:
1191-
// Should not occur.
1190+
case TryKind::Plain:
1191+
// Nothing to do.
11921192
break;
11931193
}
11941194
WriteCloseNewline();

‎test/dump/try.txt

+32-22
Original file line numberDiff line numberDiff line change
@@ -3,6 +3,9 @@
33
(module
44
(tag $e (param i32))
55
(func
6+
try
7+
nop
8+
end
69
try $try1 (result i32)
710
nop
811
i32.const 7
@@ -55,22 +58,26 @@
5558
0000021: 00 ; func body size (guess)
5659
0000022: 00 ; local decl count
5760
0000023: 06 ; try
58-
0000024: 7f ; i32
61+
0000024: 40 ; void
5962
0000025: 01 ; nop
60-
0000026: 41 ; i32.const
61-
0000027: 07 ; i32 literal
62-
0000028: 07 ; catch
63-
0000029: 00 ; catch tag
64-
000002a: 1a ; drop
65-
000002b: 41 ; i32.const
66-
000002c: 08 ; i32 literal
67-
000002d: 0b ; end
63+
0000026: 0b ; end
64+
0000027: 06 ; try
65+
0000028: 7f ; i32
66+
0000029: 01 ; nop
67+
000002a: 41 ; i32.const
68+
000002b: 07 ; i32 literal
69+
000002c: 07 ; catch
70+
000002d: 00 ; catch tag
6871
000002e: 1a ; drop
69-
000002f: 0b ; end
70-
0000021: 0e ; FIXUP func body size
71-
000001f: 10 ; FIXUP section size
72-
; move data: [1e, 30) -> [1b, 2d)
73-
; truncate to 45 (0x2d)
72+
000002f: 41 ; i32.const
73+
0000030: 08 ; i32 literal
74+
0000031: 0b ; end
75+
0000032: 1a ; drop
76+
0000033: 0b ; end
77+
0000021: 12 ; FIXUP func body size
78+
000001f: 14 ; FIXUP section size
79+
; move data: [1e, 34) -> [1b, 31)
80+
; truncate to 49 (0x31)
7481
;;; STDERR ;;)
7582
(;; STDOUT ;;;
7683

@@ -79,13 +86,16 @@ try.wasm: file format wasm 0x1
7986
Code Disassembly:
8087

8188
00001f func[0]:
82-
000020: 06 7f | try i32
89+
000020: 06 40 | try
8390
000022: 01 | nop
84-
000023: 41 07 | i32.const 7
85-
000025: 07 00 | catch 0
86-
000027: 1a | drop
87-
000028: 41 08 | i32.const 8
88-
00002a: 0b | end
89-
00002b: 1a | drop
90-
00002c: 0b | end
91+
000023: 0b | end
92+
000024: 06 7f | try i32
93+
000026: 01 | nop
94+
000027: 41 07 | i32.const 7
95+
000029: 07 00 | catch 0
96+
00002b: 1a | drop
97+
00002c: 41 08 | i32.const 8
98+
00002e: 0b | end
99+
00002f: 1a | drop
100+
000030: 0b | end
91101
;;; STDOUT ;;)

‎test/parse/expr/bad-try-no-catch.txt

-14
This file was deleted.

‎test/parse/expr/try.txt

+6
Original file line numberDiff line numberDiff line change
@@ -3,6 +3,12 @@
33
(module
44
(tag (param i32))
55

6+
;; no catch
7+
(func
8+
try
9+
nop
10+
end)
11+
612
;; bare
713
(func
814
try

‎test/roundtrip/fold-try.txt

+8
Original file line numberDiff line numberDiff line change
@@ -2,6 +2,10 @@
22
;;; ARGS: --stdout --fold-exprs --enable-exceptions --debug-names
33
(module
44
(func (result i32)
5+
try (result i32)
6+
i32.const 6
7+
end
8+
drop
59
try (result i32)
610
nop
711
i32.const 7
@@ -14,6 +18,10 @@
1418
(module
1519
(type (;0;) (func (result i32)))
1620
(func (;0;) (type 0) (result i32)
21+
(drop
22+
(try (result i32) ;; label = @1
23+
(do
24+
(i32.const 6))))
1725
(try (result i32) ;; label = @1
1826
(do
1927
(nop)

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