* quit value gets saturated to ranges
* add documentation
* minimal changes
* refactor
* small fix
* add documentation
* fixes
* Update lib/system.nim
Co-authored-by: Juan Carlos <juancarlospaco@gmail.com>
Co-authored-by: Juan Carlos <juancarlospaco@gmail.com>
* Remove the use of usrToCell in gcMark [backport:1.2]
Recently, we've discovered a GC crash resulting from inlining of
the memory allocation procs that allowed the compiler to avoid
maintaining any references to the "user pointer" on the stack.
Instead, a "cell pointer" appeared there and all field accesses
were performed with adjusted offsets. This interfered with the
ability of the GC to mark the correct cell in the conservative
stack scans which lead to premature collection of objects.
More details here:
af69b3ceae
This commit closes another theoretical loophole that may lead to
the same problem. If a short proc is accessing both the object and
its reference count in a short sequence of instructions, the compiler
may be enticed to reduce the number of registers being used by storing
only a single pointer to the object and using offsets when reading
and writing fields. A perfectly good strategy would be to store only
the cell pointer, so the reference count updates can be performed
without applying offsets. Accessing the fields of the object requires
offsets anyway, but these can be adjusted at compile-time without any
loss. Following this strategy will lead to the same problem of marking
a wrong cell during the conservative stack scan, leading to premature
collection.
The problem is avoided by not using `usrToCell` in `gcMark`. Since
the cell discovery logic can already handle interior pointers, the
user pointers don't need to be adjusted for the GC to function correctly.
This is taken from:
af69b3ceae
Full original comment:
This is to avoid heavy inlining happening when two allocation calls
would occur shortly after each other.
This inlining would sometimes be accompanied with an optimisation
as the compiler is able to see that cellToUsr ending the first
allocation call is shortly followed by an usrToCell call. The
pointer arithmetic is redundant and the compiler can eliminate it,
leaving only the cell address in a register (and later the stack)
instead of the actual pointer to the user data, as one would expect.
This combined with a GC collect cycle will cause the stack scan to
only notice the cell address, which is of no good due to a usrToCell
in the gcMark call which shifts that address to an adjacent cell.
This means that the actual cell of importance will not get marked
and thus cause a premature collection of that cell. BOOM.
* Error -> Defect for defects
The distinction between Error and Defect is subjective,
context-dependent and somewhat arbitrary, so when looking at an
exception, it's hard to guess what it is - this happens often when
looking at a `raises` list _without_ opening the corresponding
definition and digging through layers of inheritance.
With the help of a little consistency in naming, it's at least possible
to start disentangling the two error types and the standard lib can set
a good example here.
* allow defects to be caught even for --exceptions:goto (WIP)
* implemented the new --panics:on|off switch; refs https://github.com/nim-lang/RFCs/issues/180
* new implementation for integer overflow checking
* produce a warning if a user-defined exception type inherits from Exception directly
* applied Timothee's suggestions; improved the documentation and replace the term 'checked runtime check' by 'panic'
* fixes#13627
* don't inherit from Exception directly
* system/gc: don't export markStackAndRegisters
* compiler/cgen: unexport internal symbols
As these functions are Nim-specific walkaround against C's optimization
schemes, they don't serve any purpose being exported.
* compiler/cgen: don't export global var unless marked
* compiler/ccgthreadvars: don't export threadvar unless marked
* tests/dll/visibility: also check for exports
This ensure that these changes don't break manual exports.
* compiler/cgen: hide all variables created for constants
* compiler/ccgtypes: don't export RTTI variables
* compiler/ccgexprs: make all complex const static
* nimbase.h: fix export for windows
* compiler/cgen, ccgthreadvars: export variables correctly
For C/C++ variables, `extern` means that the variable is defined in an
another unit. Added a new N_LIB_EXPORT_VAR to correctly export
variables.
* right shift is now by default sign preserving
* fix hashString and semfold
* enable arithmetic shift right globally for CI
* fix typo
* remove xxx
* use oldShiftRight as flag
* apply feedback
* add changelog entry
* move IO subsystem into its own module; refs #10385
* make standalone test compile again
* make C++ examples compile again
* make more tests green
* make sysAssert and gcAssert work again
* ucontext backend (default on unix)
* setjmp backend
* fibers backend (default and required on windows)
* Fixed coroutine loop timing issues
* Fixed saving of xmm registers on x64 windows
* Fixed alignment issues
* Updated coroutine sample with cooperative fibonacci calculation.
* Disable glibc security features only when platform jump functions are used
* Removed dependency on fasm.
* Using fiber api on windows.
* Other platforms and compilers will use built in assembler and .S files or API provided by platform libc.
* Replaced stack switching procs with `coroExecWithStack()` which never returns. This makes compiler always generate proper code.
