Also, say "guard-offset pages" rather than just "guard pages" to describe the
region of a heap which is never accessible and which exists to support
optimizations for heap accesses with offsets.
And, introduce a `Uimm64` immediate type, and make all heap fields use
`Uimm64` instead of `Imm64` since they really are unsigned.
* Clarify Cranelift's design with respect to mid-level optimization.
Cranelift doesn't currently do much mid-level optimization, however it
is something we're thinking about, so remove text describing it as out of
scope, and add more text explaining the vision for how it would fit into
the overall system.
* Fix verifier printing to print instruction encodings consistently.
Use `FuncWriter::write_instruction` for all instructions so that
encodings are printed consistently.
* Make use-before-def errors mention the relevant value.
* When there are verifier errors, print a message at the end.
* Make verifier errors prettier.
Fix the length of the "^~~~~" to match the printed entity, and print the
error messsage on its own line.
* Clean up "test verifier" failure messages.
* Tidy the uses-value-from-itself error.
The use instruction is the same as the def instruction, so don't print
both. Also, the use instruction is already being printed at the
beginning, so don't print it again at the end.
This is a followup to af2a952aabd82cf401cc664d0262b139ff92d86b. It
teaches the spilling pass to use the is_ghost() property to test whether
to visit instructions. This fixes a bug handling multiple return values
with fallthrough_return.
Add an explicit "is_ghost" property to selected instructions, and use
that to determine whether reload and coloring should visit instructions.
This allows them to visit fallthrough_return instructions and insert
fills and register moves as needed.
When one value is used multiple times for separate return values, we
need to copy it to produce a new value, so that each value can be
allocated a different register.
* Introduce a `TargetFrontendConfig` type.
`TargetFrontendConfig` is information specific to the target which is
provided to frontends to allow them to produce Cranelift IR for the
target. Currently this includes the pointer size and the default calling
convention.
The default calling convention is now inferred from the target, rather
than being a setting. cranelift-native is now just a provider of target
information, rather than also being a provider of settings, which gives
it a clearer role.
And instead of having cranelift-frontend routines require the whole
`TargetIsa`, just require the `TargetFrontendConfig`, and add a way to
get the `TargetFrontendConfig` from a `Module`.
Fixes#529.
Fixes#555.
We no longer need the Ubuntu LTS restriction, so now the only only
constraint I'm aware of is Firefox's policy. Fortunately, that tracks
the latest stable delayed by only two weeks. So this puts is at
Rust 1.29 now.
* Rename size to base_size and introduce a compute_size function;
* Add infra to inspect in/outs registers when computing the size of an instruction;
* Remove the GPR_SAFE_DEREF and GPR_ZERO_DEREF_SAFE register classes on x86 (fixes#335);
* Move `return_at_end` out of Settings and into the wasm FuncEnvironment.
The `return_at_end` flag supports users that want to append a custom
epilogue to Cranelift-produced functions. It arranges for functions to
always return via a single return statement at the end, and users are
expected to remove this return to append their code.
This patch makes two changes:
- First, introduce a `fallthrough_return` instruction and use that
instead of adding a `return` at the end. That's simpler than having
users remove the `return` themselves.
- Second, move this setting out of the Settings and into the wasm
FuncEnvironment. This flag isn't something the code generator uses,
it's something that the wasm translator uses. The code generator
needs to preserve the property, however we can give the
`fallthrough_return` instruction properties to ensure this as needed,
such as marking it non-cloneable.
