Add a wasmtime settings command to print Cranelift settings.
This commit adds the `wasmtime settings` command to print out available Cranelift settings for a target (defaults to the host). The compile command has been updated to remove the Cranelift ISA options in favor of encouraging users to use `wasmtime settings` to discover what settings are available. This will reduce the maintenance cost for syncing the compile command with Cranelift ISA flags.
This commit is contained in:
Peter Huene
@@ -5,29 +5,29 @@ pub(crate) fn define() -> SettingGroup {
|
||||
|
||||
settings.add_enum(
|
||||
"regalloc",
|
||||
r#"Register allocator to use with the MachInst backend.
|
||||
"Register allocator to use with the MachInst backend.",
|
||||
r#"
|
||||
This selects the register allocator as an option among those offered by the `regalloc.rs`
|
||||
crate. Please report register allocation bugs to the maintainers of this crate whenever
|
||||
possible.
|
||||
|
||||
This selects the register allocator as an option among those offered by the `regalloc.rs`
|
||||
crate. Please report register allocation bugs to the maintainers of this crate whenever
|
||||
possible.
|
||||
Note: this only applies to target that use the MachInst backend. As of 2020-04-17, this
|
||||
means the x86_64 backend doesn't use this yet.
|
||||
|
||||
Note: this only applies to target that use the MachInst backend. As of 2020-04-17, this
|
||||
means the x86_64 backend doesn't use this yet.
|
||||
Possible values:
|
||||
|
||||
Possible values:
|
||||
|
||||
- `backtracking` is a greedy, backtracking register allocator as implemented in
|
||||
Spidermonkey's optimizing tier IonMonkey. It may take more time to allocate registers, but
|
||||
it should generate better code in general, resulting in better throughput of generated
|
||||
code.
|
||||
- `backtracking_checked` is the backtracking allocator with additional self checks that may
|
||||
take some time to run, and thus these checks are disabled by default.
|
||||
- `experimental_linear_scan` is an experimental linear scan allocator. It may take less
|
||||
time to allocate registers, but generated code's quality may be inferior. As of
|
||||
2020-04-17, it is still experimental and it should not be used in production settings.
|
||||
- `experimental_linear_scan_checked` is the linear scan allocator with additional self
|
||||
checks that may take some time to run, and thus these checks are disabled by default.
|
||||
"#,
|
||||
- `backtracking` is a greedy, backtracking register allocator as implemented in
|
||||
Spidermonkey's optimizing tier IonMonkey. It may take more time to allocate registers, but
|
||||
it should generate better code in general, resulting in better throughput of generated
|
||||
code.
|
||||
- `backtracking_checked` is the backtracking allocator with additional self checks that may
|
||||
take some time to run, and thus these checks are disabled by default.
|
||||
- `experimental_linear_scan` is an experimental linear scan allocator. It may take less
|
||||
time to allocate registers, but generated code's quality may be inferior. As of
|
||||
2020-04-17, it is still experimental and it should not be used in production settings.
|
||||
- `experimental_linear_scan_checked` is the linear scan allocator with additional self
|
||||
checks that may take some time to run, and thus these checks are disabled by default.
|
||||
"#,
|
||||
vec![
|
||||
"backtracking",
|
||||
"backtracking_checked",
|
||||
@@ -38,24 +38,23 @@ pub(crate) fn define() -> SettingGroup {
|
||||
|
||||
settings.add_enum(
|
||||
"opt_level",
|
||||
"Optimization level for generated code.",
|
||||
r#"
|
||||
Optimization level:
|
||||
Supported levels:
|
||||
|
||||
- none: Minimise compile time by disabling most optimizations.
|
||||
- speed: Generate the fastest possible code
|
||||
- speed_and_size: like "speed", but also perform transformations
|
||||
aimed at reducing code size.
|
||||
- `none`: Minimise compile time by disabling most optimizations.
|
||||
- `speed`: Generate the fastest possible code
|
||||
- `speed_and_size`: like "speed", but also perform transformations aimed at reducing code size.
|
||||
"#,
|
||||
vec!["none", "speed", "speed_and_size"],
|
||||
);
|
||||
|
||||
settings.add_bool(
|
||||
"enable_verifier",
|
||||
"Run the Cranelift IR verifier at strategic times during compilation.",
|
||||
r#"
|
||||
Run the Cranelift IR verifier at strategic times during compilation.
|
||||
|
||||
This makes compilation slower but catches many bugs. The verifier is always enabled by
|
||||
default, which is useful during development.
|
||||
This makes compilation slower but catches many bugs. The verifier is always enabled by
|
||||
default, which is useful during development.
|
||||
"#,
|
||||
true,
|
||||
);
|
||||
@@ -65,110 +64,110 @@ pub(crate) fn define() -> SettingGroup {
|
||||
// `colocated` flag on external functions and global values.
|
||||
settings.add_bool(
|
||||
"is_pic",
|
||||
"Enable Position-Independent Code generation",
|
||||
"Enable Position-Independent Code generation.",
|
||||
"",
|
||||
false,
|
||||
);
|
||||
|
||||
settings.add_bool(
|
||||
"use_colocated_libcalls",
|
||||
"Use colocated libcalls.",
|
||||
r#"
|
||||
Use colocated libcalls.
|
||||
|
||||
Generate code that assumes that libcalls can be declared "colocated",
|
||||
meaning they will be defined along with the current function, such that
|
||||
they can use more efficient addressing.
|
||||
"#,
|
||||
"#,
|
||||
false,
|
||||
);
|
||||
|
||||
settings.add_bool(
|
||||
"avoid_div_traps",
|
||||
"Generate explicit checks around native division instructions to avoid their trapping.",
|
||||
r#"
|
||||
Generate explicit checks around native division instructions to avoid
|
||||
their trapping.
|
||||
|
||||
This is primarily used by SpiderMonkey which doesn't install a signal
|
||||
handler for SIGFPE, but expects a SIGILL trap for division by zero.
|
||||
|
||||
On ISAs like ARM where the native division instructions don't trap,
|
||||
this setting has no effect - explicit checks are always inserted.
|
||||
"#,
|
||||
"#,
|
||||
false,
|
||||
);
|
||||
|
||||
settings.add_bool(
|
||||
"enable_float",
|
||||
"Enable the use of floating-point instructions.",
|
||||
r#"
|
||||
Enable the use of floating-point instructions
|
||||
|
||||
Disabling use of floating-point instructions is not yet implemented.
|
||||
"#,
|
||||
"#,
|
||||
true,
|
||||
);
|
||||
|
||||
settings.add_bool(
|
||||
"enable_nan_canonicalization",
|
||||
"Enable NaN canonicalization.",
|
||||
r#"
|
||||
Enable NaN canonicalization
|
||||
|
||||
This replaces NaNs with a single canonical value, for users requiring
|
||||
entirely deterministic WebAssembly computation. This is not required
|
||||
by the WebAssembly spec, so it is not enabled by default.
|
||||
"#,
|
||||
"#,
|
||||
false,
|
||||
);
|
||||
|
||||
settings.add_bool(
|
||||
"enable_pinned_reg",
|
||||
r#"Enable the use of the pinned register.
|
||||
|
||||
This register is excluded from register allocation, and is completely under the control of
|
||||
the end-user. It is possible to read it via the get_pinned_reg instruction, and to set it
|
||||
with the set_pinned_reg instruction.
|
||||
"Enable the use of the pinned register.",
|
||||
r#"
|
||||
This register is excluded from register allocation, and is completely under the control of
|
||||
the end-user. It is possible to read it via the get_pinned_reg instruction, and to set it
|
||||
with the set_pinned_reg instruction.
|
||||
"#,
|
||||
false,
|
||||
);
|
||||
|
||||
settings.add_bool(
|
||||
"use_pinned_reg_as_heap_base",
|
||||
r#"Use the pinned register as the heap base.
|
||||
"Use the pinned register as the heap base.",
|
||||
r#"
|
||||
Enabling this requires the enable_pinned_reg setting to be set to true. It enables a custom
|
||||
legalization of the `heap_addr` instruction so it will use the pinned register as the heap
|
||||
base, instead of fetching it from a global value.
|
||||
|
||||
Enabling this requires the enable_pinned_reg setting to be set to true. It enables a custom
|
||||
legalization of the `heap_addr` instruction so it will use the pinned register as the heap
|
||||
base, instead of fetching it from a global value.
|
||||
|
||||
Warning! Enabling this means that the pinned register *must* be maintained to contain the
|
||||
heap base address at all times, during the lifetime of a function. Using the pinned
|
||||
register for other purposes when this is set is very likely to cause crashes.
|
||||
Warning! Enabling this means that the pinned register *must* be maintained to contain the
|
||||
heap base address at all times, during the lifetime of a function. Using the pinned
|
||||
register for other purposes when this is set is very likely to cause crashes.
|
||||
"#,
|
||||
false,
|
||||
);
|
||||
|
||||
settings.add_bool("enable_simd", "Enable the use of SIMD instructions.", false);
|
||||
settings.add_bool(
|
||||
"enable_simd",
|
||||
"Enable the use of SIMD instructions.",
|
||||
"",
|
||||
false,
|
||||
);
|
||||
|
||||
settings.add_bool(
|
||||
"enable_atomics",
|
||||
"Enable the use of atomic instructions",
|
||||
"",
|
||||
true,
|
||||
);
|
||||
|
||||
settings.add_bool(
|
||||
"enable_safepoints",
|
||||
"Enable safepoint instruction insertions.",
|
||||
r#"
|
||||
Enable safepoint instruction insertions.
|
||||
|
||||
This will allow the emit_stack_maps() function to insert the safepoint
|
||||
instruction on top of calls and interrupt traps in order to display the
|
||||
live reference values at that point in the program.
|
||||
"#,
|
||||
"#,
|
||||
false,
|
||||
);
|
||||
|
||||
settings.add_enum(
|
||||
"tls_model",
|
||||
r#"
|
||||
Defines the model used to perform TLS accesses.
|
||||
"#,
|
||||
"Defines the model used to perform TLS accesses.",
|
||||
"",
|
||||
vec!["none", "elf_gd", "macho", "coff"],
|
||||
);
|
||||
|
||||
@@ -176,9 +175,9 @@ pub(crate) fn define() -> SettingGroup {
|
||||
|
||||
settings.add_enum(
|
||||
"libcall_call_conv",
|
||||
"Defines the calling convention to use for LibCalls call expansion.",
|
||||
r#"
|
||||
Defines the calling convention to use for LibCalls call expansion,
|
||||
since it may be different from the ISA default calling convention.
|
||||
This may be different from the ISA default calling convention.
|
||||
|
||||
The default value is to use the same calling convention as the ISA
|
||||
default calling convention.
|
||||
@@ -202,9 +201,8 @@ pub(crate) fn define() -> SettingGroup {
|
||||
|
||||
settings.add_num(
|
||||
"baldrdash_prologue_words",
|
||||
"Number of pointer-sized words pushed by the baldrdash prologue.",
|
||||
r#"
|
||||
Number of pointer-sized words pushed by the baldrdash prologue.
|
||||
|
||||
Functions with the `baldrdash` calling convention don't generate their
|
||||
own prologue and epilogue. They depend on externally generated code
|
||||
that pushes a fixed number of words in the prologue and restores them
|
||||
@@ -213,15 +211,14 @@ pub(crate) fn define() -> SettingGroup {
|
||||
This setting configures the number of pointer-sized words pushed on the
|
||||
stack when the Cranelift-generated code is entered. This includes the
|
||||
pushed return address on x86.
|
||||
"#,
|
||||
"#,
|
||||
0,
|
||||
);
|
||||
|
||||
settings.add_bool(
|
||||
"enable_llvm_abi_extensions",
|
||||
"Enable various ABI extensions defined by LLVM's behavior.",
|
||||
r#"
|
||||
Enable various ABI extensions defined by LLVM's behavior.
|
||||
|
||||
In some cases, LLVM's implementation of an ABI (calling convention)
|
||||
goes beyond a standard and supports additional argument types or
|
||||
behavior. This option instructs Cranelift codegen to follow LLVM's
|
||||
@@ -232,18 +229,18 @@ pub(crate) fn define() -> SettingGroup {
|
||||
registers. The Fastcall implementation otherwise does not support
|
||||
`i128` arguments, and will panic if they are present and this
|
||||
option is not set.
|
||||
"#,
|
||||
"#,
|
||||
false,
|
||||
);
|
||||
|
||||
settings.add_bool(
|
||||
"unwind_info",
|
||||
"Generate unwind information.",
|
||||
r#"
|
||||
Generate unwind info. This increases metadata size and compile time,
|
||||
but allows for the debugger to trace frames, is needed for GC tracing
|
||||
that relies on libunwind (such as in Wasmtime), and is
|
||||
unconditionally needed on certain platforms (such as Windows) that
|
||||
must always be able to unwind.
|
||||
This increases metadata size and compile time, but allows for the
|
||||
debugger to trace frames, is needed for GC tracing that relies on
|
||||
libunwind (such as in Wasmtime), and is unconditionally needed on
|
||||
certain platforms (such as Windows) that must always be able to unwind.
|
||||
"#,
|
||||
true,
|
||||
);
|
||||
@@ -253,6 +250,7 @@ pub(crate) fn define() -> SettingGroup {
|
||||
settings.add_bool(
|
||||
"emit_all_ones_funcaddrs",
|
||||
"Emit not-yet-relocated function addresses as all-ones bit patterns.",
|
||||
"",
|
||||
false,
|
||||
);
|
||||
|
||||
@@ -260,32 +258,27 @@ pub(crate) fn define() -> SettingGroup {
|
||||
|
||||
settings.add_bool(
|
||||
"enable_probestack",
|
||||
r#"
|
||||
Enable the use of stack probes, for calling conventions which support this
|
||||
functionality.
|
||||
"#,
|
||||
"Enable the use of stack probes for supported calling conventions.",
|
||||
"",
|
||||
true,
|
||||
);
|
||||
|
||||
settings.add_bool(
|
||||
"probestack_func_adjusts_sp",
|
||||
r#"
|
||||
Set this to true of the stack probe function modifies the stack pointer
|
||||
itself.
|
||||
"#,
|
||||
"Enable if the stack probe adjusts the stack pointer.",
|
||||
"",
|
||||
false,
|
||||
);
|
||||
|
||||
settings.add_num(
|
||||
"probestack_size_log2",
|
||||
"The log2 of the size of the stack guard region.",
|
||||
r#"
|
||||
The log2 of the size of the stack guard region.
|
||||
|
||||
Stack frames larger than this size will have stack overflow checked
|
||||
by calling the probestack function.
|
||||
|
||||
The default is 12, which translates to a size of 4096.
|
||||
"#,
|
||||
"#,
|
||||
12,
|
||||
);
|
||||
|
||||
@@ -294,6 +287,7 @@ pub(crate) fn define() -> SettingGroup {
|
||||
settings.add_bool(
|
||||
"enable_jump_tables",
|
||||
"Enable the use of jump tables in generated machine code.",
|
||||
"",
|
||||
true,
|
||||
);
|
||||
|
||||
@@ -301,16 +295,15 @@ pub(crate) fn define() -> SettingGroup {
|
||||
|
||||
settings.add_bool(
|
||||
"enable_heap_access_spectre_mitigation",
|
||||
"Enable Spectre mitigation on heap bounds checks.",
|
||||
r#"
|
||||
Enable Spectre mitigation on heap bounds checks.
|
||||
This is a no-op for any heap that needs no bounds checks; e.g.,
|
||||
if the limit is static and the guard region is large enough that
|
||||
the index cannot reach past it.
|
||||
|
||||
This is a no-op for any heap that needs no bounds checks; e.g.,
|
||||
if the limit is static and the guard region is large enough that
|
||||
the index cannot reach past it.
|
||||
|
||||
This option is enabled by default because it is highly
|
||||
recommended for secure sandboxing. The embedder should consider
|
||||
the security implications carefully before disabling this option.
|
||||
This option is enabled by default because it is highly
|
||||
recommended for secure sandboxing. The embedder should consider
|
||||
the security implications carefully before disabling this option.
|
||||
"#,
|
||||
true,
|
||||
);
|
||||
|
||||
Reference in New Issue
Block a user