Files
wasmtime/cranelift/codegen/src/isa/x64/mod.rs
2022-02-04 23:15:16 -08:00

336 lines
12 KiB
Rust

//! X86_64-bit Instruction Set Architecture.
use self::inst::EmitInfo;
use super::TargetIsa;
use crate::ir::{condcodes::IntCC, Function};
#[cfg(feature = "unwind")]
use crate::isa::unwind::systemv;
use crate::isa::x64::{inst::regs::create_reg_universe_systemv, settings as x64_settings};
use crate::isa::Builder as IsaBuilder;
use crate::machinst::{
compile, MachCompileResult, MachTextSectionBuilder, TextSectionBuilder, VCode,
};
use crate::result::CodegenResult;
use crate::settings::{self as shared_settings, Flags};
use alloc::{boxed::Box, vec::Vec};
use core::fmt;
use regalloc::{PrettyPrint, RealRegUniverse, Reg};
use target_lexicon::Triple;
mod abi;
pub mod encoding;
mod inst;
mod lower;
mod settings;
/// An X64 backend.
pub(crate) struct X64Backend {
triple: Triple,
flags: Flags,
x64_flags: x64_settings::Flags,
reg_universe: RealRegUniverse,
}
impl X64Backend {
/// Create a new X64 backend with the given (shared) flags.
fn new_with_flags(triple: Triple, flags: Flags, x64_flags: x64_settings::Flags) -> Self {
let reg_universe = create_reg_universe_systemv(&flags);
Self {
triple,
flags,
x64_flags,
reg_universe,
}
}
fn compile_vcode(&self, func: &Function, flags: Flags) -> CodegenResult<VCode<inst::Inst>> {
// This performs lowering to VCode, register-allocates the code, computes
// block layout and finalizes branches. The result is ready for binary emission.
let emit_info = EmitInfo::new(flags.clone(), self.x64_flags.clone());
let abi = Box::new(abi::X64ABICallee::new(&func, flags, self.isa_flags())?);
compile::compile::<Self>(&func, self, abi, &self.reg_universe, emit_info)
}
}
impl TargetIsa for X64Backend {
fn compile_function(
&self,
func: &Function,
want_disasm: bool,
) -> CodegenResult<MachCompileResult> {
let flags = self.flags();
let vcode = self.compile_vcode(func, flags.clone())?;
let (buffer, bb_starts, bb_edges) = vcode.emit();
let buffer = buffer.finish();
let frame_size = vcode.frame_size();
let value_labels_ranges = vcode.value_labels_ranges();
let stackslot_offsets = vcode.stackslot_offsets().clone();
let disasm = if want_disasm {
Some(vcode.show_rru(Some(&create_reg_universe_systemv(flags))))
} else {
None
};
Ok(MachCompileResult {
buffer,
frame_size,
disasm,
value_labels_ranges,
stackslot_offsets,
bb_starts,
bb_edges,
})
}
fn flags(&self) -> &Flags {
&self.flags
}
fn isa_flags(&self) -> Vec<shared_settings::Value> {
self.x64_flags.iter().collect()
}
fn name(&self) -> &'static str {
"x64"
}
fn triple(&self) -> &Triple {
&self.triple
}
fn unsigned_add_overflow_condition(&self) -> IntCC {
// Unsigned `<`; this corresponds to the carry flag set on x86, which
// indicates an add has overflowed.
IntCC::UnsignedLessThan
}
#[cfg(feature = "unwind")]
fn emit_unwind_info(
&self,
result: &MachCompileResult,
kind: crate::machinst::UnwindInfoKind,
) -> CodegenResult<Option<crate::isa::unwind::UnwindInfo>> {
use crate::isa::unwind::UnwindInfo;
use crate::machinst::UnwindInfoKind;
Ok(match kind {
UnwindInfoKind::SystemV => {
let mapper = self::inst::unwind::systemv::RegisterMapper;
Some(UnwindInfo::SystemV(
crate::isa::unwind::systemv::create_unwind_info_from_insts(
&result.buffer.unwind_info[..],
result.buffer.data().len(),
&mapper,
)?,
))
}
UnwindInfoKind::Windows => Some(UnwindInfo::WindowsX64(
crate::isa::unwind::winx64::create_unwind_info_from_insts::<
self::inst::unwind::winx64::RegisterMapper,
>(&result.buffer.unwind_info[..])?,
)),
_ => None,
})
}
#[cfg(feature = "unwind")]
fn create_systemv_cie(&self) -> Option<gimli::write::CommonInformationEntry> {
Some(inst::unwind::systemv::create_cie())
}
#[cfg(feature = "unwind")]
fn map_regalloc_reg_to_dwarf(&self, reg: Reg) -> Result<u16, systemv::RegisterMappingError> {
inst::unwind::systemv::map_reg(reg).map(|reg| reg.0)
}
fn text_section_builder(&self, num_funcs: u32) -> Box<dyn TextSectionBuilder> {
Box::new(MachTextSectionBuilder::<inst::Inst>::new(num_funcs))
}
}
impl fmt::Display for X64Backend {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.debug_struct("MachBackend")
.field("name", &self.name())
.field("triple", &self.triple())
.field("flags", &format!("{}", self.flags()))
.finish()
}
}
/// Create a new `isa::Builder`.
pub(crate) fn isa_builder(triple: Triple) -> IsaBuilder {
IsaBuilder {
triple,
setup: x64_settings::builder(),
constructor: isa_constructor,
}
}
fn isa_constructor(
triple: Triple,
shared_flags: Flags,
builder: shared_settings::Builder,
) -> Box<dyn TargetIsa> {
let isa_flags = x64_settings::Flags::new(&shared_flags, builder);
let backend = X64Backend::new_with_flags(triple, shared_flags, isa_flags);
Box::new(backend)
}
#[cfg(test)]
mod test {
use super::*;
use crate::cursor::{Cursor, FuncCursor};
use crate::ir::{types::*, SourceLoc, ValueLabel, ValueLabelStart};
use crate::ir::{AbiParam, ExternalName, Function, InstBuilder, Signature};
use crate::isa::CallConv;
use crate::settings;
use crate::settings::Configurable;
use core::str::FromStr;
use cranelift_entity::EntityRef;
use target_lexicon::Triple;
/// We have to test cold blocks by observing final machine code,
/// rather than VCode, because the VCode orders blocks in lowering
/// order, not emission order. (The exact difference between the
/// two is that cold blocks are sunk in the latter.) We might as
/// well do the test here, where we have a backend to use.
#[test]
fn test_cold_blocks() {
let name = ExternalName::testcase("test0");
let mut sig = Signature::new(CallConv::SystemV);
sig.params.push(AbiParam::new(I32));
sig.returns.push(AbiParam::new(I32));
let mut func = Function::with_name_signature(name, sig);
// Add debug info: this tests the debug machinery wrt cold
// blocks as well.
func.dfg.collect_debug_info();
let bb0 = func.dfg.make_block();
let arg0 = func.dfg.append_block_param(bb0, I32);
let bb1 = func.dfg.make_block();
let bb2 = func.dfg.make_block();
let bb3 = func.dfg.make_block();
let bb1_param = func.dfg.append_block_param(bb1, I32);
let bb3_param = func.dfg.append_block_param(bb3, I32);
let mut pos = FuncCursor::new(&mut func);
pos.insert_block(bb0);
pos.set_srcloc(SourceLoc::new(1));
let v0 = pos.ins().iconst(I32, 0x1234);
pos.set_srcloc(SourceLoc::new(2));
let v1 = pos.ins().iadd(arg0, v0);
pos.ins().brnz(v1, bb1, &[v1]);
pos.ins().jump(bb2, &[]);
pos.insert_block(bb1);
pos.set_srcloc(SourceLoc::new(3));
let v2 = pos.ins().isub(v1, v0);
pos.set_srcloc(SourceLoc::new(4));
let v3 = pos.ins().iadd(v2, bb1_param);
pos.ins().brnz(v1, bb2, &[]);
pos.ins().jump(bb3, &[v3]);
pos.func.layout.set_cold(bb2);
pos.insert_block(bb2);
pos.set_srcloc(SourceLoc::new(5));
let v4 = pos.ins().iadd(v1, v0);
pos.ins().brnz(v4, bb2, &[]);
pos.ins().jump(bb1, &[v4]);
pos.insert_block(bb3);
pos.set_srcloc(SourceLoc::new(6));
pos.ins().return_(&[bb3_param]);
// Create some debug info. Make one label that follows all the
// values around. Note that this is usually done via an API on
// the FunctionBuilder, but that's in cranelift_frontend
// (i.e., a higher level of the crate DAG) so we have to build
// it manually here.
pos.func.dfg.values_labels.as_mut().unwrap().insert(
v0,
crate::ir::ValueLabelAssignments::Starts(vec![ValueLabelStart {
from: SourceLoc::new(1),
label: ValueLabel::new(1),
}]),
);
pos.func.dfg.values_labels.as_mut().unwrap().insert(
v1,
crate::ir::ValueLabelAssignments::Starts(vec![ValueLabelStart {
from: SourceLoc::new(2),
label: ValueLabel::new(1),
}]),
);
pos.func.dfg.values_labels.as_mut().unwrap().insert(
v2,
crate::ir::ValueLabelAssignments::Starts(vec![ValueLabelStart {
from: SourceLoc::new(3),
label: ValueLabel::new(1),
}]),
);
pos.func.dfg.values_labels.as_mut().unwrap().insert(
v3,
crate::ir::ValueLabelAssignments::Starts(vec![ValueLabelStart {
from: SourceLoc::new(4),
label: ValueLabel::new(1),
}]),
);
pos.func.dfg.values_labels.as_mut().unwrap().insert(
v4,
crate::ir::ValueLabelAssignments::Starts(vec![ValueLabelStart {
from: SourceLoc::new(5),
label: ValueLabel::new(1),
}]),
);
let mut shared_flags_builder = settings::builder();
shared_flags_builder.set("opt_level", "none").unwrap();
shared_flags_builder.set("enable_verifier", "true").unwrap();
let shared_flags = settings::Flags::new(shared_flags_builder);
let isa_flags = x64_settings::Flags::new(&shared_flags, x64_settings::builder());
let backend = X64Backend::new_with_flags(
Triple::from_str("x86_64").unwrap(),
shared_flags,
isa_flags,
);
let result = backend
.compile_function(&mut func, /* want_disasm = */ false)
.unwrap();
let code = result.buffer.data();
// 00000000 55 push rbp
// 00000001 4889E5 mov rbp,rsp
// 00000004 4889FE mov rsi,rdi
// 00000007 81C634120000 add esi,0x1234
// 0000000D 85F6 test esi,esi
// 0000000F 0F841B000000 jz near 0x30
// 00000015 4889F7 mov rdi,rsi
// 00000018 4889F0 mov rax,rsi
// 0000001B 81E834120000 sub eax,0x1234
// 00000021 01F8 add eax,edi
// 00000023 85F6 test esi,esi
// 00000025 0F8505000000 jnz near 0x30
// 0000002B 4889EC mov rsp,rbp
// 0000002E 5D pop rbp
// 0000002F C3 ret
// 00000030 4889F7 mov rdi,rsi <--- cold block
// 00000033 81C734120000 add edi,0x1234
// 00000039 85FF test edi,edi
// 0000003B 0F85EFFFFFFF jnz near 0x30
// 00000041 E9D2FFFFFF jmp 0x18
let golden = vec![
85, 72, 137, 229, 72, 137, 254, 129, 198, 52, 18, 0, 0, 133, 246, 15, 132, 27, 0, 0, 0,
72, 137, 247, 72, 137, 240, 129, 232, 52, 18, 0, 0, 1, 248, 133, 246, 15, 133, 5, 0, 0,
0, 72, 137, 236, 93, 195, 72, 137, 247, 129, 199, 52, 18, 0, 0, 133, 255, 15, 133, 239,
255, 255, 255, 233, 210, 255, 255, 255,
];
assert_eq!(code, &golden[..]);
}
}