Previously, overflow and underflow both caused this to return `nil`, which causes several problems:
* It does not distinguish between a large but valid input and a malformed input. `Float("3.402824e+38")` is perfectly well-formed but returns nil
* It differs from how the compiler handles literals. As a result, `Float(3.402824e+38)` is very different from `Float("3.402824e+38")`
* It's inconsistent with Foundation Scanner()
* It's inconsistent with other programming languages
This is exactly the same as #25313
Fixes rdar://problem/36990878
Most SwiftShims were put in the swift namespace in C++ mode which broke certain things when importing them in a swift file in C++ mode. This was OK when they were only imported as part of the swift runtime but, now they are used in C++ mode both in the swift runtime and when C++ interop is enabled.
This broke when C++ interop was enabled because the `Swift` module contains references to symbols in the SwiftShims headers which are built without C++ interop enabled (no "swift" namespace). But, when C++ interop is enabled, the SwiftShims headers would put everything in the swift namespace meaning the symbols couldn't be found in the global namespace. Then, the compiler would error when trying to deserialize the Swift module.
Currently, _swift_stdlib_strtoX_clocale_impl is present here twice: one
general definition for most platforms that wraps the standard strto*
functions, and another general definition with a slightly different
implementation for Cygwin, Haiku, and Windows, using stringstreams to
achieve a similar result. Furthermore, for Windows, the stringstream
implementation isn't even used but specialized away.
Firstly: the stringstream implementation is slightly broken, since it
causes some of the unit tests to fail; secondly, there is an awful lot
of repetition here that is ripe for simplification.
Instead of duplicating twice and using template specialization to induce
platform-specific behavior, we massage the stringstream implementation
for Cygwin and Haiku into something that looks like a standard strto*
function.
Now we have one definition (for each type) of swift_strto*_l. By
default, the _swift_stdlib_strto*_clocale stubs will refer to strto*_l,
and platforms withing to make use of the swift_strto*_l stubs can make
the necessary preprocessor definitions to utilize them.
Instead of putting the stubs alongside the redefinitions in each platform
preprocessor section, split these out, in anticipation for consolidation
in the next commit.
Here the template specializations can be adapted to a strto* wrapper, for
use with the general function-pointer implementation of
_swift_stdlib_strtoX_clocale_impl.
The template defined for Cygwin and friends does not handle failure cases
properly so the NumericParsing unit test fails. To get the correct test
behavior, we need to use an implementation such as like in the Windows
specializations or the non-Cygwin implementation that takes a function
pointer.
However, adding additional specializations would be too wordy, and
OpenBSD doesn't have locale-dependent definitions of the relevant strto*
functions. We could add a specialization for a two-argument function
pointer, but that becomes too repetitive.
Instead, implement a few stubs and use the preprocessor, a la the
implementation for Android.
This reduces the dependency on `LLVMSupport`. This is the first step
towards helping move towards a local fork of the LLVM ADT to ensure that
static linking of the Swift runtime and core library does not result in
ODR violations.
Extend SwiftDtoa to provide optimal formatting for Float16 and use that for `Float16.description` and `Float16.debugDescription`.
Notes on signaling NaNs: LLVM's Float16 support passes Float16s on x86
by legalizing to Float32. This works well for most purposes but incidentally
loses the signaling marker from any NaN (because it's a conversion as far
as the hardware is concerned), with a side effect that the print code never
actually sees a true sNaN. This is similar to what happens with Float and
Double on i386 backends. The earlier code here tried to detect sNaN in a
different way, but that approach isn't guaranteed to work so we decided to
make this code use the correct detection logic -- sNaN printing will just be
broken until we can get a better argument passing convention.
Resolves rdar://61414101
These should hopefully all be uncontroversial, minimal changes to deal
with progressing the build to completion on OpenBSD or addressing minor
portability issues. This is not the full set of changes to get a
successful build; other portability issues will be addressed in future
commits.
Most of this is just adding the relevant clauses to the ifdefs, but of
note in this commit:
* StdlibUnittest.swift: the default conditional in _getOSVersion assumes
an Apple platform, therefore the explicit conditional and the relevant
enums need filling out. The default conditional should be #error, but
we'll fix this in a different commit.
* tgmath.swift.gyb: inexplicably, OpenBSD is missing just lgammal_r.
Tests are updated correspondingly.
* ThreadLocalStorage.h: we use the pthread implementation, so it
seems we should typedef __swift_thread_key_t as pthread_key_t.
However, that's also a tweak for another commit.
These are supposed to be processed in the C locale always, irrespective
of the current locale. We were not doing this and so we would parse the
value incorrectly.
The conversion routines in MSVCPRT return "0" for the conversion of
"-inf" et al. Provde template specializations for `float`, `double`,
and `long double` to use `strtof`, `strtod`, and `strtold` respectively.
This fixes the lossless conversion of floating point constants.
When building on Linux, the definition of `swift_snprintf_l` would cause
an unused function warning. Expand the scope of the preprocessor guard
to encompass the function for the single use. This avoids the unused
function warning.
Some of the previously used stubs are no longer needed in newer releases
of the Android API. Android L and Android O provide the functions in
their associated versions of bionic. This is needed to build against a
newer version of the SDK.
The returned type `std::streamoff` on Windows x64 is a `long long`
rather than `int`. This results in a 64-to-32 bit shortening of the
value. Use the appropriate type to avoid the truncation.
`strlen` returns a unsigned value, but `std::streamoff` is an signed
value. Explicitly cast the value to avoid the warning about the
implicit signed conversion.
Move the duplicated compiler-rt support routines into its own source
file. This will need to be expanded for Windows. As on Linux, there
are certain builtin routines which are not available from the standard
runtime and need to be augmented for now.
* SR-106: New floating-point `description` implementation
This replaces the current implementation of `description` and
`debugDescription` for the standard floating-point types with a new
formatting routine based on a variation of Florian Loitsch' Grisu2
algorithm with changes suggested by Andrysco, Jhala, and Lerner's 2016
paper describing Errol3.
Unlike the earlier code based on `sprintf` with a fixed number of
digits, this version always chooses the optimal number of digits. As
such, we can now use the exact same output for both `description` and
`debugDescription` (except of course that `debugDescription` provides
full detail for NaNs).
The implementation has been extensively commented; people familiar with
Grisu-style algorithms should find the code easy to understand.
This implementation is:
* Fast. It uses only fixed-width integer arithmetic and has constant
memory and time requirements.
* Simple. It is only a little more complex than Loitsch' original
implementation of Grisu2. The digit decomposition logic for double is
less than 300 lines of standard C (half of which is common arithmetic
support routines).
* Always Accurate. Converting the decimal form back to binary (using an
accurate algorithm such as Clinger's) will always yield exactly the
original binary value. For the IEEE 754 formats, the round-trip will
produce exactly the same bit pattern in memory. This is an essential
requirement for JSON serialization, debugging, and logging.
* Always Short. This always selects an accurate result with the minimum
number of decimal digits. (So that `1.0 / 10.0` will always print
`0.1`.)
* Always Close. Among all accurate, short results, this always chooses
the result that is closest to the exact floating-point value. (In case
of an exact tie, it rounds the last digit even.)
This resolves SR-106 and related issues that have complained
about the floating-point `description` properties being inexact.
* Remove duplicate infinity handling
* Use defined(__SIZEOF_INT128__) to detect uint128_t support
* Separate `extracting` the integer part from `clearing` the integer part
The previous code was unnecessarily obfuscated by the attempt to combine
these two operations.
* Use `UINT32_MAX` to mask off 32 bits of a larger integer
* Correct the expected NaN results for 32-bit i386
* Make the C++ exceptions here consistent
Adding a C source file somehow exposed an issue in an unrelated C++ file.
Thanks to Joe Groff for the fix.
* Rename SwiftDtoa to ".cpp"
Having a C file in stdlib/public/runtime causes strange
build failures on Linux in unrelated C++ files.
As a workaround, rename SwiftDtoa.c to .cpp to see
if that avoids the problems.
* Revert "Make the C++ exceptions here consistent"
This reverts commit 6cd5c20566.
On `istringstream`, `tellg()` returns -1 if the stream is at the end of the file. This indicates success in this circumstance, so we should update `pos` to reflect that the whole string has been read.
NFC on platforms other than Windows, Cygwin, and Haiku.
Use the KeyPath implementation's new support for instantiating and dealing with captures to lower the generic context required to dispatch computed accessors with dependent generics.
Changes:
* Terminate all namespaces with the correct closing comment.
* Make sure argument names in comments match the corresponding parameter name.
* Remove redundant get() calls on smart pointers.
* Prefer using "override" or "final" instead of "virtual". Remove "virtual" where appropriate.
Update for SE-0107: UnsafeRawPointer
This adds a "mutating" initialize to UnsafePointer to make
Immutable -> Mutable conversions explicit.
These are quick fixes to stdlib, overlays, and test cases that are necessary
in order to remove arbitrary UnsafePointer conversions.
Many cases can be expressed better up by reworking the surrounding
code, but we first need a working starting point.
