OS X 10.9's linker has a bug that results in it failing to preserve
DWARF unwind information when passed the -no_compact_unwind flag.
This flag is passed on OS X because the unwind information for
__morestack cannot be represented by the compact unwind format.
We can work around this problem by using a more targeted approach
to disabling compact unwind information. The OS X linker looks for
a particular pattern in the DWARF unwind information and will not
attempt to convert the unwind information to the compact format.
The pattern in question is the return address register being saved
twice to the same location.
Fixes#6849.
I'll flip this on after doing a snapshot. This syntax may or may not
stay around, and managed boxes are currently not very useful. They have
the same overall performance characteristics as `std::rc::Rc`, but are
significantly slower, allocate larger boxes and hold onto the memory
beyond when it is needed due to lacking move semantics.
There are currently two useful aspects of the type:
* the dereference sugar, which we should implement for `Rc`
* the annihilator freeing cycles at the end of the task
I'll flip this on after doing a snapshot. This syntax may or may not
stay around, and managed boxes are currently not very useful. They have
the same overall performance characteristics as `std::rc::Rc`, but are
significantly slower, allocate larger boxes and hold onto the memory
beyond when it is needed due to lacking move semantics.
There are currently two useful aspects of the type:
* the dereference sugar, which we should implement for `Rc`
* the annihilator freeing cycles at the end of the task
OS X 10.9's linker has a bug that results in it failing to preserve
DWARF unwind information when passed the -no_compact_unwind flag.
This flag is passed on OS X because the unwind information for
__morestack cannot be represented by the compact unwind format.
We can work around this problem by using a more targeted approach
to disabling compact unwind information. The OS X linker looks for
a particular pattern in the DWARF unwind information and will not
attempt to convert the unwind information to the compact format.
The pattern in question is the return address register being saved
twice to the same location.
Fixes#6849.
When re-exporting a trait/structure/enum, then we need to propagate the
reachability of the type through the methods that are defined on it.
Closes#9906Closes#9968
Fixes#9882
Note that the actual checking code is inside a if false in order to compile libstd properly.
libstd uses asm! in rt. If we put ```#[feature(asm)]``` in libstd, it fails to build at stage0 beacause the
asm feature is not known yet by the snapshot compiler.
We must wait that this PR arrives into the snapshot in order to actually activate the checking code.
This commit re-introduces the functionality of __morestack in a way that it was
not originally anticipated. Rust does not currently have segmented stacks,
rather just large stack segments. We do not detect when these stack segments are
overrun currently, but this commit leverages __morestack in order to check this.
This commit purges a lot of the old __morestack and stack limit C++
functionality, migrating the necessary chunks to rust. The stack limit is now
entirely maintained in rust, and the "main logic bits" of __morestack are now
also implemented in rust as well.
I put my best effort into validating that this currently builds and runs successfully on osx and linux 32/64 bit, but I was unable to get this working on windows. We never did have unwinding through __morestack frames, and although I tried poking at it for a bit, I was unable to understand why we don't get unwinding right now.
A focus of this commit is to implement as much of the logic in rust as possible. This involved some liberal usage of `no_split_stack` in various locations, along with some use of the `asm!` macro (scary). I modified a bit of C++ to stop calling `record_sp_limit` because this is no longer defined in C++, rather in rust.
Another consequence of this commit is that `thread_local_storage::{get, set}` must both be flagged with `#[rust_stack]`. I've briefly looked at the implementations on osx/linux/windows to ensure that they're pretty small stacks, and I'm pretty sure that they're definitely less than 20K stacks, so we probably don't have a lot to worry about.
Other things worthy of note:
* The default stack size is now 4MB instead of 2MB. This is so that when we request 2MB to call a C function you don't immediately overflow because you have consumed any stack at all.
* `asm!` is actually pretty cool, maybe we could actually define context switching with it?
* I wanted to add links to the internet about all this jazz of storing information in TLS, but I was only able to find a link for the windows implementation. Otherwise my suggestion is just "disassemble on that arch and see what happens"
* I put my best effort forward on arm/mips to tweak __morestack correctly, we have no ability to test this so an extra set of eyes would be useful on these spots.
* This is all really tricky stuff, so I tried to put as many comments as I thought were necessary, but if anything is still unclear (or I completely forgot to take something into account), I'm willing to write more!
This commit resumes management of the stack boundaries and limits when switching
between tasks. This additionally leverages the __morestack function to run code
on "stack overflow". The current behavior is to abort the process, but this is
probably not the best behavior in the long term (for deails, see the comment I
wrote up in the stack exhaustion routine).
r? @alexcrichton On most platforms, the time granularity is 1 sec or more, so comparing
dates in tests that check whether rebuilding did or didn't happen leads
to spurious failures. Instead, test the same thing by making an output
file read-only and trapping attempts to write to it.
This stops labeling everything as "is private" when in fact the destination may
be public. Instead, the clause "is inaccessible" is used and the private part of
the flag is called out with a "is private" message.
Closes#9793
Previously an ExprLit was created *per byte* causing a huge increase in memory
bloat. This adds a new `lit_binary` to contain a literal of binary data, which
is currently only used by the include_bin! syntax extension. This massively
speeds up compilation times of the shootout-k-nucleotide-pipes test
before:
time: 469s
memory: 6GB
assertion failure in LLVM (section too large)
after:
time: 2.50s
memory: 124MB
Closes#2598
Previously an ExprLit was created *per byte* causing a huge increase in memory
bloat. This adds a new `lit_binary` to contain a literal of binary data, which
is currently only used by the include_bin! syntax extension. This massively
speeds up compilation times of the shootout-k-nucleotide-pipes test
before:
time: 469s
memory: 6GB
assertion failure in LLVM (section too large)
after:
time: 2.50s
memory: 124MB
Closes#2598
The code generation previously assumed a reference could not alter the
value in a way the destructor would notice. This is an incorrect
assumption for `&mut`, and is also incorrect for an `&` pointer to a
non-`Freeze` type.
Closes#7972
The code generation previously assumed a reference could not alter the
value in a way the destructor would notice. This is an incorrect
assumption for `&mut`, and is also incorrect for an `&` pointer to a
non-`Freeze` type.
Closes#7972
The goal here is to avoid requiring a division or multiplication to compare against the length. The bounds check previously used an incorrect micro-optimization to replace the division by a multiplication, but now neither is necessary *for slices*. Unique/managed vectors will have to do a division to get the length until they are reworked/replaced.
Delete the following API functions:
- set_dirname()
- with_dirname()
- set_filestem()
- with_filestem()
- add_extension()
- file_path()
Also change pop() to return a boolean instead of an owned copy of the
old filename.
