Add new MachInst backend and ARM64 support.

cranelift/codegen/Cargo.toml

@@ -24,6 +24,7 @@ gimli = { version = "0.20.0", default-features = false, features = ["write"], op
 smallvec = { version = "1.0.0" }
 thiserror = "1.0.4"
 byteorder = { version = "1.3.2", default-features = false }
+regalloc = "0.0.17"
 # It is a goal of the cranelift-codegen crate to have minimal external dependencies.
 # Please don't add any unless they are essential to the task of creating binary
 # machine code. Integration tests that need external dependencies can be

cranelift/codegen/meta/src/isa/arm64/mod.rs

@@ -54,7 +54,9 @@ pub(crate) fn define(shared_defs: &mut SharedDefinitions) -> TargetIsa {
     let mut a64 = CpuMode::new("A64");
 
     // TODO refine these.
+    let expand_flags = shared_defs.transform_groups.by_name("expand_flags");
     let narrow_flags = shared_defs.transform_groups.by_name("narrow_flags");
+    a64.legalize_monomorphic(expand_flags);
     a64.legalize_default(narrow_flags);
 
     let cpu_modes = vec![a64];

cranelift/codegen/src/binemit/mod.rs

@@ -54,7 +54,9 @@ pub enum Reloc {
     X86GOTPCRel4,
     /// Arm32 call target
     Arm32Call,
-    /// Arm64 call target
+    /// Arm64 call target. Encoded as bottom 26 bits of instruction. This
+    /// value is sign-extended, multiplied by 4, and added to the PC of
+    /// the call instruction to form the destination address.
     Arm64Call,
     /// RISC-V call target
     RiscvCall,

cranelift/codegen/src/context.rs

@@ -19,8 +19,10 @@ use crate::flowgraph::ControlFlowGraph;
 use crate::ir::Function;
 use crate::isa::TargetIsa;
 use crate::legalize_function;
+use crate::legalizer::simple_legalize;
 use crate::licm::do_licm;
 use crate::loop_analysis::LoopAnalysis;
+use crate::machinst::MachCompileResult;
 use crate::nan_canonicalization::do_nan_canonicalization;
 use crate::postopt::do_postopt;
 use crate::redundant_reload_remover::RedundantReloadRemover;
@@ -55,6 +57,12 @@ pub struct Context {
 
     /// Redundant-reload remover context.
     pub redundant_reload_remover: RedundantReloadRemover,
+
+    /// Result of MachBackend compilation, if computed.
+    pub mach_compile_result: Option<MachCompileResult>,
+
+    /// Flag: do we want a disassembly with the MachCompileResult?
+    pub want_disasm: bool,
 }
 
 impl Context {
@@ -78,6 +86,8 @@ impl Context {
             regalloc: regalloc::Context::new(),
             loop_analysis: LoopAnalysis::new(),
             redundant_reload_remover: RedundantReloadRemover::new(),
+            mach_compile_result: None,
+            want_disasm: false,
         }
     }
 
@@ -89,6 +99,14 @@ impl Context {
         self.regalloc.clear();
         self.loop_analysis.clear();
         self.redundant_reload_remover.clear();
+        self.mach_compile_result = None;
+        self.want_disasm = false;
+    }
+
+    /// Set the flag to request a disassembly when compiling with a
+    /// `MachBackend` backend.
+    pub fn set_disasm(&mut self, val: bool) {
+        self.want_disasm = val;
     }
 
     /// Compile the function, and emit machine code into a `Vec<u8>`.
@@ -130,9 +148,13 @@ impl Context {
     pub fn compile(&mut self, isa: &dyn TargetIsa) -> CodegenResult<CodeInfo> {
         let _tt = timing::compile();
         self.verify_if(isa)?;
-        debug!("Compiling:\n{}", self.func.display(isa));
 
         let opt_level = isa.flags().opt_level();
+        debug!(
+            "Compiling (opt level {:?}):\n{}",
+            opt_level,
+            self.func.display(isa)
+        );
 
         self.compute_cfg();
         if opt_level != OptLevel::None {
@@ -141,6 +163,7 @@ impl Context {
         if isa.flags().enable_nan_canonicalization() {
             self.canonicalize_nans(isa)?;
         }
+
         self.legalize(isa)?;
         if opt_level != OptLevel::None {
             self.postopt(isa)?;
@@ -149,23 +172,32 @@ impl Context {
             self.licm(isa)?;
             self.simple_gvn(isa)?;
         }
+
         self.compute_domtree();
         self.eliminate_unreachable_code(isa)?;
         if opt_level != OptLevel::None {
             self.dce(isa)?;
         }
-        self.regalloc(isa)?;
-        self.prologue_epilogue(isa)?;
-        if opt_level == OptLevel::Speed || opt_level == OptLevel::SpeedAndSize {
-            self.redundant_reload_remover(isa)?;
-        }
-        if opt_level == OptLevel::SpeedAndSize {
-            self.shrink_instructions(isa)?;
-        }
-        let result = self.relax_branches(isa);
 
-        debug!("Compiled:\n{}", self.func.display(isa));
-        result
+        if let Some(backend) = isa.get_mach_backend() {
+            let result = backend.compile_function(&mut self.func, self.want_disasm)?;
+            let info = result.code_info();
+            self.mach_compile_result = Some(result);
+            Ok(info)
+        } else {
+            self.regalloc(isa)?;
+            self.prologue_epilogue(isa)?;
+            if opt_level == OptLevel::Speed || opt_level == OptLevel::SpeedAndSize {
+                self.redundant_reload_remover(isa)?;
+            }
+            if opt_level == OptLevel::SpeedAndSize {
+                self.shrink_instructions(isa)?;
+            }
+            let result = self.relax_branches(isa);
+
+            debug!("Compiled:\n{}", self.func.display(isa));
+            result
+        }
     }
 
     /// Emit machine code directly into raw memory.
@@ -191,7 +223,11 @@ impl Context {
     ) -> CodeInfo {
         let _tt = timing::binemit();
         let mut sink = MemoryCodeSink::new(mem, relocs, traps, stackmaps);
-        isa.emit_function_to_memory(&self.func, &mut sink);
+        if let Some(ref result) = &self.mach_compile_result {
+            result.sections.emit(&mut sink);
+        } else {
+            isa.emit_function_to_memory(&self.func, &mut sink);
+        }
         sink.info
     }
 
@@ -279,9 +315,15 @@ impl Context {
         // TODO: Avoid doing this when legalization doesn't actually mutate the CFG.
         self.domtree.clear();
         self.loop_analysis.clear();
-        legalize_function(&mut self.func, &mut self.cfg, isa);
-        debug!("Legalized:\n{}", self.func.display(isa));
-        self.verify_if(isa)
+        if isa.get_mach_backend().is_some() {
+            // Run some specific legalizations only.
+            simple_legalize(&mut self.func, &mut self.cfg, isa);
+            self.verify_if(isa)
+        } else {
+            legalize_function(&mut self.func, &mut self.cfg, isa);
+            debug!("Legalized:\n{}", self.func.display(isa));
+            self.verify_if(isa)
+        }
     }
 
     /// Perform post-legalization rewrites on the function.

cranelift/codegen/src/dce.rs

@@ -6,40 +6,10 @@
 use crate::cursor::{Cursor, FuncCursor};
 use crate::dominator_tree::DominatorTree;
 use crate::entity::EntityRef;
-use crate::ir::instructions::InstructionData;
-use crate::ir::{DataFlowGraph, Function, Inst, Opcode};
+use crate::inst_predicates::{any_inst_results_used, has_side_effect};
+use crate::ir::Function;
 use crate::timing;
 
-/// Test whether the given opcode is unsafe to even consider for DCE.
-fn trivially_unsafe_for_dce(opcode: Opcode) -> bool {
-    opcode.is_call()
-        || opcode.is_branch()
-        || opcode.is_terminator()
-        || opcode.is_return()
-        || opcode.can_trap()
-        || opcode.other_side_effects()
-        || opcode.can_store()
-}
-
-/// Preserve instructions with used result values.
-fn any_inst_results_used(inst: Inst, live: &[bool], dfg: &DataFlowGraph) -> bool {
-    dfg.inst_results(inst).iter().any(|v| live[v.index()])
-}
-
-/// Load instructions without the `notrap` flag are defined to trap when
-/// operating on inaccessible memory, so we can't DCE them even if the
-/// loaded value is unused.
-fn is_load_with_defined_trapping(opcode: Opcode, data: &InstructionData) -> bool {
-    if !opcode.can_load() {
-        return false;
-    }
-    match *data {
-        InstructionData::StackLoad { .. } => false,
-        InstructionData::Load { flags, .. } => !flags.notrap(),
-        _ => true,
-    }
-}
-
 /// Perform DCE on `func`.
 pub fn do_dce(func: &mut Function, domtree: &mut DominatorTree) {
     let _tt = timing::dce();
@@ -50,10 +20,7 @@ pub fn do_dce(func: &mut Function, domtree: &mut DominatorTree) {
         let mut pos = FuncCursor::new(func).at_bottom(block);
         while let Some(inst) = pos.prev_inst() {
             {
-                let data = &pos.func.dfg[inst];
-                let opcode = data.opcode();
-                if trivially_unsafe_for_dce(opcode)
-                    || is_load_with_defined_trapping(opcode, &data)
+                if has_side_effect(pos.func, inst)
                     || any_inst_results_used(inst, &live, &pos.func.dfg)
                 {
                     for arg in pos.func.dfg.inst_args(inst) {

cranelift/codegen/src/inst_predicates.rs

@@ -0,0 +1,42 @@
+//! Instruction predicates/properties, shared by various analyses.
+
+use crate::ir::{DataFlowGraph, Function, Inst, InstructionData, Opcode};
+use cranelift_entity::EntityRef;
+
+/// Preserve instructions with used result values.
+pub fn any_inst_results_used(inst: Inst, live: &[bool], dfg: &DataFlowGraph) -> bool {
+    dfg.inst_results(inst).iter().any(|v| live[v.index()])
+}
+
+/// Test whether the given opcode is unsafe to even consider as side-effect-free.
+fn trivially_has_side_effects(opcode: Opcode) -> bool {
+    opcode.is_call()
+        || opcode.is_branch()
+        || opcode.is_terminator()
+        || opcode.is_return()
+        || opcode.can_trap()
+        || opcode.other_side_effects()
+        || opcode.can_store()
+}
+
+/// Load instructions without the `notrap` flag are defined to trap when
+/// operating on inaccessible memory, so we can't treat them as side-effect-free even if the loaded
+/// value is unused.
+fn is_load_with_defined_trapping(opcode: Opcode, data: &InstructionData) -> bool {
+    if !opcode.can_load() {
+        return false;
+    }
+    match *data {
+        InstructionData::StackLoad { .. } => false,
+        InstructionData::Load { flags, .. } => !flags.notrap(),
+        _ => true,
+    }
+}
+
+/// Does the given instruction have any side-effect that would preclude it from being removed when
+/// its value is unused?
+pub fn has_side_effect(func: &Function, inst: Inst) -> bool {
+    let data = &func.dfg[inst];
+    let opcode = data.opcode();
+    trivially_has_side_effects(opcode) || is_load_with_defined_trapping(opcode, data)
+}

cranelift/codegen/src/ir/function.rs

@@ -238,13 +238,21 @@ impl Function {
 
     /// Wrapper around `encode` which assigns `inst` the resulting encoding.
     pub fn update_encoding(&mut self, inst: ir::Inst, isa: &dyn TargetIsa) -> Result<(), Legalize> {
-        self.encode(inst, isa).map(|e| self.encodings[inst] = e)
+        if isa.get_mach_backend().is_some() {
+            Ok(())
+        } else {
+            self.encode(inst, isa).map(|e| self.encodings[inst] = e)
+        }
     }
 
     /// Wrapper around `TargetIsa::encode` for encoding an existing instruction
     /// in the `Function`.
     pub fn encode(&self, inst: ir::Inst, isa: &dyn TargetIsa) -> Result<Encoding, Legalize> {
-        isa.encode(&self, &self.dfg[inst], self.dfg.ctrl_typevar(inst))
+        if isa.get_mach_backend().is_some() {
+            Ok(Encoding::new(0, 0))
+        } else {
+            isa.encode(&self, &self.dfg[inst], self.dfg.ctrl_typevar(inst))
+        }
     }
 
     /// Starts collection of debug information.

cranelift/codegen/src/ir/immediates.rs

@@ -57,6 +57,11 @@ impl Imm64 {
     pub fn wrapping_neg(self) -> Self {
         Self(self.0.wrapping_neg())
     }
+
+    /// Return bits of this immediate.
+    pub fn bits(&self) -> i64 {
+        self.0
+    }
 }
 
 impl Into<i64> for Imm64 {