* cranelift: Add stack support to the interpreter
We also change the approach for heap loads and stores.
Previously we would use the offset as the address to the heap. However,
this approach does not allow using the load/store instructions to
read/write from both the heap and the stack.
This commit changes the addressing mechanism of the interpreter. We now
return the real addresses from the addressing instructions
(stack_addr/heap_addr), and instead check if the address passed into
the load/store instructions points to an area in the heap or the stack.
* cranelift: Add virtual addresses to cranelift interpreter
Adds a Virtual Addressing scheme that was discussed as a better
alternative to returning the real addresses.
The virtual addresses are split into 4 regions (stack, heap, tables and
global values), and the address itself is composed of an `entry` field
and an `offset` field. In general the `entry` field corresponds to the
instance of the resource (e.g. table5 is entry 5) and the `offset` field
is a byte offset inside that entry.
There is one exception to this which is the stack, where due to only
having one stack, the whole address is an offset field.
The number of bits in entry vs offset fields is variable with respect to
the `region` and the address size (32bits vs 64bits). This is done
because with 32 bit addresses we would have to compromise on heap size,
or have a small number of global values / tables. With 64 bit addresses
we do not have to compromise on this, but we need to support 32 bit
addresses.
* cranelift: Remove interpreter trap codes
* cranelift: Calculate frame_offset when entering or exiting a frame
* cranelift: Add safe read/write interface to DataValue
* cranelift: DataValue write full 128bit slot for booleans
* cranelift: Use DataValue accessors for trampoline.
* cranelift: Initial fuzzer implementation
* cranelift: Generate multiple test cases in fuzzer
* cranelift: Separate function generator in fuzzer
* cranelift: Insert random instructions in fuzzer
* cranelift: Rename gen_testcase
* cranelift: Implement div for unsigned values in interpreter
* cranelift: Run all test cases in fuzzer
* cranelift: Comment options in function_runner
* cranelift: Improve fuzzgen README.md
* cranelift: Fuzzgen remove unused variable
* cranelift: Fuzzer code style fixes
Thanks! @bjorn3
* cranelift: Fix nits in CLIF fuzzer
Thanks @cfallin!
* cranelift: Implement Arbitrary for TestCase
* cranelift: Remove gen_testcase
* cranelift: Move fuzzers to wasmtime fuzz directory
* cranelift: CLIF-Fuzzer ignore tests that produce traps
* cranelift: CLIF-Fuzzer create new fuzz target to validate generated testcases
* cranelift: Store clif-fuzzer config in a separate struct
* cranelift: Generate variables upfront per function
* cranelift: Prevent publishing of fuzzgen crate
Enabling runtests for the s390x backend exposed a pre-existing endian bug with handling bool test case return values.
These are written as integers of the same width by the trampoline, but are always read out as the Rust "bool" type. This happens to work on little-endian systems, but fails for any boolean type larger than 1 byte on big-endian systems.
See: https://github.com/bytecodealliance/wasmtime/pull/2964#issuecomment-855879866
This PR switches the default backend on x86, for both the
`cranelift-codegen` crate and for Wasmtime, to the new
(`MachInst`-style, `VCode`-based) backend that has been under
development and testing for some time now.
The old backend is still available by default in builds with the
`old-x86-backend` feature, or by requesting `BackendVariant::Legacy`
from the appropriate APIs.
As part of that switch, it adds some more runtime-configurable plumbing
to the testing infrastructure so that tests can be run using the
appropriate backend. `clif-util test` is now capable of parsing a
backend selector option from filetests and instantiating the correct
backend.
CI has been updated so that the old x86 backend continues to run its
tests, just as we used to run the new x64 backend separately.
At some point, we will remove the old x86 backend entirely, once we are
satisfied that the new backend has not caused any unforeseen issues and
we do not need to revert.
* Rewrite interpreter generically
This change re-implements the Cranelift interpreter to use generic values; this makes it possible to do abstract interpretation of Cranelift instructions. In doing so, the interpretation state is extracted from the `Interpreter` structure and is accessed via a `State` trait; this makes it possible to not only more clearly observe the interpreter's state but also to interpret using a dummy state (e.g. `ImmutableRegisterState`). This addition made it possible to implement more of the Cranelift instructions (~70%, ignoring the x86-specific instructions).
* Replace macros with closures
As discussed in #2251, in order to be very confident that NaN signaling bits are correctly handled by the compiler, this switches `DataValue` to use Cranelift's `Ieee32` and `Ieee64` structures. This makes it a bit more inconvenient to interpreter Cranelift FP operations but this should change to something like `rustc_apfloat` in the future.
* Switch CI back to nightly channel
I think all upstream issues are now fixed so we should be good to switch
back to nightly from our previously pinned version.
* Fix doc warnings
Also add configuration to CI to fail doc generation if any links are
broken. Unfortunately we can't blanket deny all warnings in rustdoc
since some are unconditional warnings, but for now this is hopefully
good enough.
Closes#1947
* Improve output display of RunCommand
The previous use of Debug for displaying `print` and `run` results was less than clear.
* Avoid checking the types of vectors during trampoline construction
Because DataValue only understands `V128` vectors, we avoid type-checking vector values when constructing the trampoline arguments.
* Improve the documentation of the filetest `run` command
Adds an up-to-date example of how to use the `run` and `print` directives and includes an actual use of the new directives in a SIMD arithmetic filetest.
This resolves the work started in https://github.com/bytecodealliance/cranelift/pull/1231 and https://github.com/bytecodealliance/wasmtime/pull/1436. Cranelift filetests currently have the ability to run CLIF functions with a signature like `() -> b*` and check that the result is true under the `test run` directive. This PR adds the ability to call functions with arbitrary arguments and non-boolean returns and either print the result or check against a list of expected results:
- `run` commands look like `; run: %add(2, 2) == 4` or `; run: %add(2, 2) != 5` and verify that the executed CLIF function returns the expected value
- `print` commands look like `; print: %add(2, 2)` and print the result of the function to stdout
To make this work, this PR compiles a single Cranelift `Function` into a `CompiledFunction` using a `SingleFunctionCompiler`. Because we will not know the signature of the function until runtime, we use a `Trampoline` to place the values in the appropriate location for the calling convention; this should look a lot like what @alexcrichton is doing with `VMTrampoline` in wasmtime (see 3b7cb6ee64/crates/api/src/func.rs (L510-L526), 3b7cb6ee64/crates/jit/src/compiler.rs (L260)). To avoid re-compiling `Trampoline`s for the same function signatures, `Trampoline`s are cached in the `SingleFunctionCompiler`.
* Manually rename BasicBlock to BlockPredecessor
BasicBlock is a pair of (Ebb, Inst) that is used to represent the
basic block subcomponent of an Ebb that is a predecessor to an Ebb.
Eventually we will be able to remove this struct, but for now it
makes sense to give it a non-conflicting name so that we can start
to transition Ebb to represent a basic block.
I have not updated any comments that refer to BasicBlock, as
eventually we will remove BlockPredecessor and replace with Block,
which is a basic block, so the comments will become correct.
* Manually rename SSABuilder block types to avoid conflict
SSABuilder has its own Block and BlockData types. These along with
associated identifier will cause conflicts in a later commit, so
they are renamed to be more verbose here.
* Automatically rename 'Ebb' to 'Block' in *.rs
* Automatically rename 'EBB' to 'block' in *.rs
* Automatically rename 'ebb' to 'block' in *.rs
* Automatically rename 'extended basic block' to 'basic block' in *.rs
* Automatically rename 'an basic block' to 'a basic block' in *.rs
* Manually update comment for `Block`
`Block`'s wikipedia article required an update.
* Automatically rename 'an `Block`' to 'a `Block`' in *.rs
* Automatically rename 'extended_basic_block' to 'basic_block' in *.rs
* Automatically rename 'ebb' to 'block' in *.clif
* Manually rename clif constant that contains 'ebb' as substring to avoid conflict
* Automatically rename filecheck uses of 'EBB' to 'BB'
'regex: EBB' -> 'regex: BB'
'$EBB' -> '$BB'
* Automatically rename 'EBB' 'Ebb' to 'block' in *.clif
* Automatically rename 'an block' to 'a block' in *.clif
* Fix broken testcase when function name length increases
Test function names are limited to 16 characters. This causes
the new longer name to be truncated and fail a filecheck test. An
outdated comment was also fixed.
* Add options for parsing test files
This change allows adding parsing parameters more easily; e.g. a parameter is needed for setting the default calling convention for functions parsed as a part of the `run` test feature.
* Set default calling convention that of the host for `test run` file tests
Previously `test run` used the parser's hard-coded CallConv::Fast as the default calling convention but with this change any test being `run` will use the default calling convention of the machine running the test. `test run` will now throw an error if the calling convention of the function does not match the host's.
* Add ability to run CLIF IR using `clif-util run [-v] {file}` and add `test run` to cranelift-filetests to allow executing CLIF
This re-factors the compile/execute parts to a FunctionRunner that is shared between cranelift-filetests and clif-util. CLIF can be now be run using `clif-util run` as well as during `clif-util test` for files with a `test run` header. As before, only functions suffixed with a `run` comment are executed. The `run: fn(...) == ...` expression syntax is left for a subsequent change.
