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Fix lifetime confusion in shadow stack pass #2596

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Merged
merged 2 commits into from
Dec 22, 2022
Merged

Fix lifetime confusion in shadow stack pass #2596

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71d1b2c
Fix lifetime confusion in shadow stack pass
dcodeIO Dec 22, 2022
3e1f079
update fixtures
dcodeIO Dec 22, 2022
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6 changes: 3 additions & 3 deletions src/passes/shadowstack.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -174,9 +174,9 @@ function needsSlot(module: Module, value: ExpressionRef): bool {
switch (_BinaryenExpressionGetId(value)) {
// no need to stack null pointers
case ExpressionId.Const: return !isConstZero(value);
// already kept in another slot
case ExpressionId.LocalGet:
case ExpressionId.LocalSet: return false; // tee
// note: can't omit a slot when assigning from another local since the other
// local might have shorter lifetime and become reassigned, say in a loop,
// then no longer holding on to the previous value in its stack slot.
}
return true;
}
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149 changes: 134 additions & 15 deletions tests/compiler/NonNullable.debug.wat
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Original file line number Diff line number Diff line change
Expand Up @@ -142,13 +142,44 @@
i32.const 0
return
)
(func $~start (type $none_=>_none)
call $start:NonNullable
)
(func $~stack_check (type $none_=>_none)
global.get $~lib/memory/__stack_pointer
global.get $~lib/memory/__data_end
i32.lt_s
if
i32.const 33152
i32.const 33200
i32.const 1
i32.const 1
call $~lib/builtins/abort
unreachable
end
)
(func $~lib/string/String.__eq (type $i32_i32_=>_i32) (param $left i32) (param $right i32) (result i32)
(local $leftLength i32)
(local $3 i32)
global.get $~lib/memory/__stack_pointer
i32.const 8
i32.sub
global.set $~lib/memory/__stack_pointer
call $~stack_check
global.get $~lib/memory/__stack_pointer
i64.const 0
i64.store $0
local.get $left
local.get $right
i32.eq
if
i32.const 1
local.set $3
global.get $~lib/memory/__stack_pointer
i32.const 8
i32.add
global.set $~lib/memory/__stack_pointer
local.get $3
return
end
local.get $left
Expand All @@ -163,40 +194,117 @@
end
if
i32.const 0
local.set $3
global.get $~lib/memory/__stack_pointer
i32.const 8
i32.add
global.set $~lib/memory/__stack_pointer
local.get $3
return
end
local.get $left
local.set $3
global.get $~lib/memory/__stack_pointer
local.get $3
i32.store $0
local.get $3
call $~lib/string/String#get:length
local.set $leftLength
local.get $leftLength
local.get $right
local.set $3
global.get $~lib/memory/__stack_pointer
local.get $3
i32.store $0
local.get $3
call $~lib/string/String#get:length
i32.ne
if
i32.const 0
local.set $3
global.get $~lib/memory/__stack_pointer
i32.const 8
i32.add
global.set $~lib/memory/__stack_pointer
local.get $3
return
end
local.get $left
local.set $3
global.get $~lib/memory/__stack_pointer
local.get $3
i32.store $0
local.get $3
i32.const 0
local.get $right
local.set $3
global.get $~lib/memory/__stack_pointer
local.get $3
i32.store $0 offset=4
local.get $3
i32.const 0
local.get $leftLength
call $~lib/util/string/compareImpl
i32.eqz
local.set $3
global.get $~lib/memory/__stack_pointer
i32.const 8
i32.add
global.set $~lib/memory/__stack_pointer
local.get $3
return
)
(func $~lib/string/String.__ne (type $i32_i32_=>_i32) (param $left i32) (param $right i32) (result i32)
(local $2 i32)
global.get $~lib/memory/__stack_pointer
i32.const 8
i32.sub
global.set $~lib/memory/__stack_pointer
call $~stack_check
global.get $~lib/memory/__stack_pointer
i64.const 0
i64.store $0
local.get $left
local.set $2
global.get $~lib/memory/__stack_pointer
local.get $2
i32.store $0
local.get $2
local.get $right
local.set $2
global.get $~lib/memory/__stack_pointer
local.get $2
i32.store $0 offset=4
local.get $2
call $~lib/string/String.__eq
i32.eqz
local.set $2
global.get $~lib/memory/__stack_pointer
i32.const 8
i32.add
global.set $~lib/memory/__stack_pointer
local.get $2
return
)
(func $NonNullable/assertNonNull<~lib/string/String> (type $i32_=>_none) (param $t i32)
(local $1 i32)
global.get $~lib/memory/__stack_pointer
i32.const 4
i32.sub
global.set $~lib/memory/__stack_pointer
call $~stack_check
global.get $~lib/memory/__stack_pointer
i32.const 0
i32.store $0
i32.const 0
i32.eqz
drop
local.get $t
local.set $1
global.get $~lib/memory/__stack_pointer
local.get $1
i32.store $0
local.get $1
i32.const 0
call $~lib/string/String.__ne
i32.eqz
Expand All @@ -208,31 +316,42 @@
call $~lib/builtins/abort
unreachable
end
global.get $~lib/memory/__stack_pointer
i32.const 4
i32.add
global.set $~lib/memory/__stack_pointer
)
(func $NonNullable/safetyCheck<~lib/string/String|null> (type $i32_=>_none) (param $t i32)
(local $1 i32)
global.get $~lib/memory/__stack_pointer
i32.const 4
i32.sub
global.set $~lib/memory/__stack_pointer
call $~stack_check
global.get $~lib/memory/__stack_pointer
i32.const 0
i32.store $0
local.get $t
local.set $1
global.get $~lib/memory/__stack_pointer
local.get $1
i32.store $0
local.get $1
i32.const 0
call $~lib/string/String.__ne
if
local.get $t
local.set $1
global.get $~lib/memory/__stack_pointer
local.get $1
i32.store $0
local.get $1
call $NonNullable/assertNonNull<~lib/string/String>
end
)
(func $~start (type $none_=>_none)
call $start:NonNullable
)
(func $~stack_check (type $none_=>_none)
global.get $~lib/memory/__stack_pointer
global.get $~lib/memory/__data_end
i32.lt_s
if
i32.const 33152
i32.const 33200
i32.const 1
i32.const 1
call $~lib/builtins/abort
unreachable
end
i32.const 4
i32.add
global.set $~lib/memory/__stack_pointer
)
(func $start:NonNullable (type $none_=>_none)
(local $0 i32)
Expand Down
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