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Fix invalid codegen on small to long int cast #1921

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Merged
merged 3 commits into from
Jun 24, 2021
Merged

Fix invalid codegen on small to long int cast #1921

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9151338
Fix invalid codegen on small to long int cast
dcodeIO Jun 23, 2021
c5376a0
fix
dcodeIO Jun 23, 2021
c134a2b
fix
dcodeIO Jun 23, 2021
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4 changes: 2 additions & 2 deletions src/compiler.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -3521,10 +3521,10 @@ export class Compiler extends DiagnosticEmitter {
if (currentType != contextualType.nonNullableType) { // allow assigning non-nullable to nullable
if (constraints & Constraints.CONV_EXPLICIT) {
expr = this.convertExpression(expr, currentType, contextualType, true, expression);
this.currentType = contextualType;
this.currentType = currentType = contextualType;
} else if (constraints & Constraints.CONV_IMPLICIT) {
expr = this.convertExpression(expr, currentType, contextualType, false, expression);
this.currentType = contextualType;
this.currentType = currentType = contextualType;
}
}
if (wrap) expr = this.ensureSmallIntegerWrap(expr, currentType);
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7 changes: 7 additions & 0 deletions src/flow.ts
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Expand Up @@ -1351,6 +1351,13 @@ export class Flow {
case UnaryOp.ClzI32:
case UnaryOp.CtzI32:
case UnaryOp.PopcntI32: return type.size < 7;

// sign extensions overflow if result can have high garbage bits in the target type
case UnaryOp.Extend8I32: return type.size < (type.isUnsignedIntegerValue ? 32 : 8);
case UnaryOp.Extend8I64: return type.size < (type.isUnsignedIntegerValue ? 64 : 8);
case UnaryOp.Extend16I32: return type.size < (type.isUnsignedIntegerValue ? 32 : 16);
case UnaryOp.Extend16I64: return type.size < (type.isUnsignedIntegerValue ? 64 : 16);
case UnaryOp.Extend32I64: return type.size < (type.isUnsignedIntegerValue ? 64 : 32);
Comment on lines +1355 to +1360
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@dcodeIO dcodeIO Jun 23, 2021 •
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Perhaps a comment here for review, by example of i32.extend16_s:

If the target type is unsigned, an i32.extend16_s can yield high garbage bits if the target type is smaller than u32. u32 naturally does not care about garbage bits, but any smaller unsigned integer could have garbage high 1s after the instruction.

If the target type is signed, an i32.extend16_s can yield high garbage 0s after leading 1s if the target type is smaller than i16. If the target type is i16 or larger, the instruction would set all high bits to either 0 or 1, which makes the value valid regardless.

}
break;
}
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2 changes: 0 additions & 2 deletions tests/compiler/abi.untouched.wat
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Expand Up @@ -88,7 +88,6 @@
local.set $0
end
local.get $0
i32.extend8_s
i32.eqz
i32.eqz
if
Expand Down Expand Up @@ -176,7 +175,6 @@
)
(func $abi/exportedExported (result i32)
call $abi/exported
i32.extend8_s
)
(func $abi/exportedInternal (result i32)
call $abi/internal
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4 changes: 4 additions & 0 deletions tests/compiler/cast.json
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@@ -0,0 +1,4 @@
{
"asc_flags": [
]
}
4 changes: 4 additions & 0 deletions tests/compiler/cast.optimized.wat
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@@ -0,0 +1,4 @@
(module
(memory $0 0)
(export "memory" (memory $0))
)
96 changes: 96 additions & 0 deletions tests/compiler/cast.ts
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@@ -0,0 +1,96 @@
function test<T,U>(x: T): U {
// @ts-ignore
var y = x as U;
// @ts-ignore
return y;
}

test<i8,i8>(0);
test<i8,u8>(0);
test<i8,i16>(0);
test<i8,u16>(0);
test<i8,i32>(0);
test<i8,u32>(0);
test<i8,i64>(0);
test<i8,u64>(0);
test<i8,bool>(0);

test<u8,i8>(0);
test<u8,u8>(0);
test<u8,i16>(0);
test<u8,u16>(0);
test<u8,i32>(0);
test<u8,u32>(0);
test<u8,i64>(0);
test<u8,u64>(0);
test<u8,bool>(0);

test<i16,i8>(0);
test<i16,u8>(0);
test<i16,i16>(0);
test<i16,u16>(0);
test<i16,i32>(0);
test<i16,u32>(0);
test<i16,i64>(0);
test<i16,u64>(0);
test<i16,bool>(0);

test<u16,i8>(0);
test<u16,u8>(0);
test<u16,i16>(0);
test<u16,u16>(0);
test<u16,i32>(0);
test<u16,u32>(0);
test<u16,i64>(0);
test<u16,u64>(0);
test<u16,bool>(0);

test<i32,i8>(0);
test<i32,u8>(0);
test<i32,i16>(0);
test<i32,u16>(0);
test<i32,i32>(0);
test<i32,u32>(0);
test<i32,i64>(0);
test<i32,u64>(0);
test<i32,bool>(0);

test<u32,i8>(0);
test<u32,u8>(0);
test<u32,i16>(0);
test<u32,u16>(0);
test<u32,i32>(0);
test<u32,u32>(0);
test<u32,i64>(0);
test<u32,u64>(0);
test<u32,bool>(0);

test<i64,i8>(0);
test<i64,u8>(0);
test<i64,i16>(0);
test<i64,u16>(0);
test<i64,i32>(0);
test<i64,u32>(0);
test<i64,i64>(0);
test<i64,u64>(0);
test<i64,bool>(0);

test<u64,i8>(0);
test<u64,u8>(0);
test<u64,i16>(0);
test<u64,u16>(0);
test<u64,i32>(0);
test<u64,u32>(0);
test<u64,i64>(0);
test<u64,u64>(0);
test<u64,bool>(0);

test<bool,i8>(0);
test<bool,u8>(0);
test<bool,i16>(0);
test<bool,u16>(0);
test<bool,i32>(0);
test<bool,u32>(0);
test<bool,i64>(0);
test<bool,u64>(0);
test<bool,bool>(0);
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