This caused sporadic LoadFaults with LLD 14 and above, as they
happened to lay out the (not otherwise mentioned) GOT/PLT such
that they would overlap with the stack guard page.
LLD does support the --orphan-handling=error option, which
would be useful to avoid similar problems in the future, but
then we'd need to mention all the other misc sections
(symbol table, comments) in the linker script as well.
GitHub: Fixes#1975.
In particular, i64/double are actually supposed to be aligned
to their size on RISC-V (at least according to the ELF psABI),
though it is unclear to me whether this actually caused any
issues.
`llvm-addr2line` is not included as part of the llvm binary package for Windows. This causes ARTIQ python compilations issues when conda is not used (so the `llvm-tools` conda package is not installed, which provides `llvm-addr2line` currently).
The representation of TList(T) is changed from `{T*, u32}` to
`{T*, u32}*`. The old representation forbids changing the length of a
list when the list is passed as a parameter into functions, as the
length is passed by value. The representation now matches with nac3.
We don't need to know whether there's a outer finally block
that's already implicit in the current break and continue
target.
Signed-off-by: Michael Birtwell <michael.birtwell@oxionics.com>
When we have a trys inside a loop then we want to make sure any
finallys are executed by break and continue inside this try. But
this shouldn't pull finallys defined outside the loop in to the
loop. This change resets the `outer_final` attribute when
visiting for and while loops so that this doesn't happen.
Signed-off-by: Michael Birtwell <michael.birtwell@oxionics.com>
Otherwise, the exception message might be allocated on a stack, and will
become a dangling pointer when the exception is raised.
This will break some code that constructs exceptions with a function by
passing the message as a parameter because we cannot know if the parameter
is a constant. A way to mitigate this would be to defer this check to
LLVM IR codegen stage, and do inlining first for those exception
allocation functions, but I am not sure if we will guarantee inlining
for certain functions, and whether this is really needed.
Note that because we changed exception representation from using string
names as exception identifier into using integer IDs, we need to
initialize the embedding map in order to allocate the integer IDs. Also,
we can no longer print the exception names and messages from the kernel,
we will need the host to map exception IDs to names, and may need the
host to map string IDs to actual strings (messages can be static strings
in the firmware, or strings stored in the host only).
We now check for exception IDs for lit tests, which are fixed because we
preallocated all builtin exceptions.
Instead of removing basic blocks with no predecessor, we will now mark
and remove all blocks that are unreachable from the entry block. This
can handle loops that are dead code. This is needed as we will now
generate more complicated code for exception handling which the old dead
code eliminator failed to handle.
Exceptions are now allocated in the runtime when we raise the exception,
and destroyed when we exit the catch block. Nested exception and try
block is now supported, and should behave the same as in CPython.
Exceptions raised in except blocks will now unwind through finally
blocks, matching the behavior in CPython. Reraise will now preserve
backtrace.
Phi block LLVM IR generation is modified to handle landingpads, which
one ARTIQ IR will map to multiple LLVM IR.
Exception name is replaced by exception ID, which requires no
allocation. Other strings in the exception can now be 'host-only'
strings, which is represented by a CSlice with len = usize::MAX and
ptr = key, to avoid the need for allocation when raising exceptions
through RPC.
LLVM 6 seemed not to mind the mismatch, but more recent
versions produce miscompilations without this.
Needs llvmlite support (GitHub: numba/llvmlite#702).
In the origin implementation, the `nowrite` flag literally means not writing memory at all.
Due to the usage of flags on certain functions, it results in the same issues found in artiq-zynq after optimization passes. (M-Labs/artiq-zynq#119)
A fix wrote by @dnadlinger can resolve this issue. (c1e46cc7c8)
ld.lld has a habit of not putting the headers under any load sections.
However, the headers are needed by libunwind to handle exception raised by the kernel.
Creating PT_LOAD section with FILEHDR and PHDRS solves this issue. Other PHDRS are also specified as linkers (not limited to ld.lld) will not create additional unspecified headers even when necessary.
Previously we kept GNU Binutils because they are less of a pain to support
on Windoze - the source of so many problems - but with RISC-V we need to
update LLVM anyway.
We need to check if our inference reached a fixed point. This is checked
using hash of the types in the AST, which is very slow. This patch
avoids computing the hash if we can make sure that the AST is definitely
changed, which is when we parse a new function.
For some simple programs with many functions, this can significantly
reduce the compile time by up to ~30%.
