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[stdlib] Avoid storing NULL into a Builtin.RawPointer. (#2236)

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Found by Dmitri.
This commit is contained in:
Jordan Rose
2016-04-18 16:27:10 -07:00
parent fab076e2d4
commit 6b8cd5cba7
1 changed files with 10 additions and 16 deletions
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26
stdlib/public/core/StaticString.swift
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@@ -39,12 +39,9 @@ public struct StaticString
CustomDebugStringConvertible, CustomDebugStringConvertible,
CustomReflectable { CustomReflectable {
// FIXME(ABI): RawPointer is non-nullable, but we can store a null Unicode /// Either a pointer to the start of UTF-8 data, represented as an integer,
// scalar in it. Change it to an integer. /// or an integer representation of a single Unicode scalar.
// internal var _startPtrOrData: Builtin.Word
/// Either a pointer to the start of UTF-8 data, or an integer representation
/// of a single Unicode scalar.
internal var _startPtrOrData: Builtin.RawPointer
/// If `_startPtrOrData` is a pointer, contains the length of the UTF-8 data /// If `_startPtrOrData` is a pointer, contains the length of the UTF-8 data
/// in bytes. /// in bytes.
@@ -68,7 +65,7 @@ public struct StaticString
_precondition( _precondition(
hasPointerRepresentation, hasPointerRepresentation,
"StaticString should have pointer representation") "StaticString should have pointer representation")
return UnsafePointer(_startPtrOrData) return UnsafePointer(bitPattern: UInt(_startPtrOrData))!
} }
/// The stored Unicode scalar value. /// The stored Unicode scalar value.
@@ -79,9 +76,7 @@ public struct StaticString
_precondition( _precondition(
!hasPointerRepresentation, !hasPointerRepresentation,
"StaticString should have Unicode scalar representation") "StaticString should have Unicode scalar representation")
return UnicodeScalar( return UnicodeScalar(UInt32(UInt(_startPtrOrData)))
UInt32(UInt(bitPattern: UnsafePointer<Builtin.RawPointer>(_startPtrOrData)))
)
} }
/// If `self` stores a pointer to ASCII or UTF-8 code units, the /// If `self` stores a pointer to ASCII or UTF-8 code units, the
@@ -148,7 +143,10 @@ public struct StaticString
utf8CodeUnitCount: Builtin.Word, utf8CodeUnitCount: Builtin.Word,
isASCII: Builtin.Int1 isASCII: Builtin.Int1
) { ) {
self._startPtrOrData = _start // We don't go through UnsafePointer here to make things simpler for alias
// analysis. A higher-level algorithm may be trying to make sure an
// unrelated buffer is not accessed or freed.
self._startPtrOrData = Builtin.ptrtoint_Word(_start)
self._utf8CodeUnitCount = utf8CodeUnitCount self._utf8CodeUnitCount = utf8CodeUnitCount
self._flags = Bool(isASCII) ? (0x2 as UInt8)._value : (0x0 as UInt8)._value self._flags = Bool(isASCII) ? (0x2 as UInt8)._value : (0x0 as UInt8)._value
} }
@@ -158,11 +156,7 @@ public struct StaticString
internal init( internal init(
unicodeScalar: Builtin.Int32 unicodeScalar: Builtin.Int32
) { ) {
self._startPtrOrData = self._startPtrOrData = UInt(UInt32(unicodeScalar))._builtinWordValue
unsafeBitCast(
UInt(UInt32(unicodeScalar)),
to: OpaquePointer.self
)._rawValue
self._utf8CodeUnitCount = 0._builtinWordValue self._utf8CodeUnitCount = 0._builtinWordValue
self._flags = UnicodeScalar(_builtinUnicodeScalarLiteral: unicodeScalar).isASCII self._flags = UnicodeScalar(_builtinUnicodeScalarLiteral: unicodeScalar).isASCII
? (0x3 as UInt8)._value ? (0x3 as UInt8)._value