use crate::cdsl::settings::{SettingGroup, SettingGroupBuilder};
pub(crate) fn define() -> SettingGroup {
let mut settings = SettingGroupBuilder::new("shared");
settings.add_enum(
"regalloc",
r#"Register allocator to use with the MachInst backend.
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.
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.
"#,
vec![
"backtracking",
"backtracking_checked",
"experimental_linear_scan",
"experimental_linear_scan_checked",
],
);
settings.add_enum(
"opt_level",
r#"
Optimization level:
- 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",
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.
"#,
true,
);
settings.add_bool(
"is_pic",
"Enable Position-Independent Code generation",
false,
);
settings.add_bool(
"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",
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",
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",
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.
"#,
false,
);
settings.add_bool(
"use_pinned_reg_as_heap_base",
r#"Use the pinned register as the heap base.
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.
"#,
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",
r#"
Enable safepoint instruction insertions.
This will allow the emit_stackmaps() 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.
"#,
vec!["none", "elf_gd", "macho", "coff"],
);
settings.add_enum(
"libcall_call_conv",
r#"
Defines the calling convention to use for LibCalls call expansion,
since it 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.
This list should be kept in sync with the list of calling
conventions available in isa/call_conv.rs.
"#,
vec![
"isa_default",
"fast",
"cold",
"system_v",
"windows_fastcall",
"baldrdash_system_v",
"baldrdash_windows",
"probestack",
],
);
settings.add_num(
"baldrdash_prologue_words",
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
in the epilogue.
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(
"emit_all_ones_funcaddrs",
"Emit not-yet-relocated function addresses as all-ones bit patterns.",
false,
);
settings.add_bool(
"enable_probestack",
r#"
Enable the use of stack probes, for calling conventions which support this
functionality.
"#,
true,
);
settings.add_bool(
"probestack_func_adjusts_sp",
r#"
Set this to true of the stack probe function modifies the stack pointer
itself.
"#,
false,
);
settings.add_num(
"probestack_size_log2",
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,
);
settings.add_bool(
"enable_jump_tables",
"Enable the use of jump tables in generated machine code.",
true,
);
settings.build()
}