add more cfg(unwind)

cranelift/codegen/src/isa/aarch64/inst/unwind.rs

@@ -11,6 +11,7 @@ impl UnwindInfoGenerator<Inst> for AArch64UnwindInfo {
         _kind: UnwindInfoKind,
         _insts: &[Inst],
         _insts_layout: &[CodeOffset],
+        _len: CodeOffset,
         _prologue_epilogue: &(u32, u32, Box<[(u32, u32)]>),
     ) -> CodegenResult<Option<UnwindInfo>> {
         // TODO

cranelift/codegen/src/isa/aarch64/mod.rs

@@ -77,6 +77,7 @@ impl MachBackend for AArch64Backend {
             buffer,
             frame_size,
             disasm,
+            #[cfg(feature = "unwind")]
             unwind_info: None,
         })
     }

cranelift/codegen/src/isa/arm32/inst/unwind.rs

@@ -11,6 +11,7 @@ impl UnwindInfoGenerator<Inst> for Arm32UnwindInfo {
         _kind: UnwindInfoKind,
         _insts: &[Inst],
         _insts_layout: &[CodeOffset],
+        _len: CodeOffset,
         _prologue_epilogue: &(u32, u32, Box<[(u32, u32)]>),
     ) -> CodegenResult<Option<UnwindInfo>> {
         // TODO

cranelift/codegen/src/isa/arm32/mod.rs

@@ -73,6 +73,7 @@ impl MachBackend for Arm32Backend {
             buffer,
             frame_size,
             disasm,
+            #[cfg(feature = "unwind")]
             unwind_info: None,
         })
     }

cranelift/codegen/src/isa/x64/inst/mod.rs

@@ -2708,6 +2708,7 @@ impl MachInstEmitInfo for EmitInfo {
 impl MachInstEmit for Inst {
     type State = EmitState;
     type Info = EmitInfo;
+    #[cfg(feature = "unwind")]
     type UnwindInfo = unwind::X64UnwindInfo;
 
     fn emit(&self, sink: &mut MachBuffer<Inst>, info: &Self::Info, state: &mut Self::State) {

cranelift/codegen/src/isa/x64/inst/unwind.rs

@@ -16,6 +16,7 @@ impl UnwindInfoGenerator<Inst> for X64UnwindInfo {
         kind: UnwindInfoKind,
         insts: &[Inst],
         insts_layout: &[CodeOffset],
+        len: CodeOffset,
         prologue_epilogue: &(u32, u32, Box<[(u32, u32)]>),
     ) -> CodegenResult<Option<UnwindInfo>> {
         // Assumption: RBP is being used as the frame pointer for both calling conventions
@@ -24,6 +25,7 @@ impl UnwindInfoGenerator<Inst> for X64UnwindInfo {
             UnwindInfoKind::SystemV => systemv::create_unwind_info(
                 insts,
                 insts_layout,
+                len,
                 prologue_epilogue,
                 Some(regs::rbp()),
             )?

cranelift/codegen/src/isa/x64/inst/unwind/systemv.rs

@@ -183,12 +183,10 @@ impl InstructionBuilder {
 pub(crate) fn create_unwind_info(
     insts: &[Inst],
     insts_layout: &[u32],
+    len: u32,
     prologue_epilogue: &(u32, u32, Box<[(u32, u32)]>),
     frame_register: Option<Reg>,
 ) -> CodegenResult<Option<UnwindInfo>> {
-    let len = *insts_layout.last().unwrap();
-    assert!(len > 0);
-
     let mut builder = InstructionBuilder::new(frame_register);
 
     let prologue_start = prologue_epilogue.0 as usize;

cranelift/codegen/src/isa/x64/mod.rs

@@ -59,6 +59,7 @@ impl MachBackend for X64Backend {
         let buffer = vcode.emit();
         let buffer = buffer.finish();
         let frame_size = vcode.frame_size();
+        #[cfg(feature = "unwind")]
         let unwind_info = vcode.unwind_info()?;
 
         let disasm = if want_disasm {
@@ -71,6 +72,7 @@ impl MachBackend for X64Backend {
             buffer,
             frame_size,
             disasm,
+            #[cfg(feature = "unwind")]
             unwind_info,
         })
     }

cranelift/codegen/src/machinst/mod.rs

@@ -99,6 +99,7 @@
 use crate::binemit::{CodeInfo, CodeOffset, StackMap};
 use crate::ir::condcodes::IntCC;
 use crate::ir::{Function, Type};
+#[cfg(feature = "unwind")]
 use crate::isa::unwind;
 use crate::result::CodegenResult;
 use crate::settings::Flags;
@@ -391,6 +392,7 @@ pub trait UnwindInfoGenerator<I: MachInstEmit> {
         kind: UnwindInfoKind,
         insts: &[I],
         insts_layout: &[CodeOffset],
+        len: CodeOffset,
         prologue_epilogue: &(u32, u32, Box<[(u32, u32)]>),
     ) -> CodegenResult<Option<unwind::UnwindInfo>>;
 }

cranelift/codegen/src/machinst/vcode.rs

@@ -18,10 +18,7 @@
 //! backend pipeline.
 
 use crate::ir::{self, types, SourceLoc};
-#[cfg(feature = "unwind")]
-use crate::isa::unwind;
 use crate::machinst::*;
-use crate::result::CodegenResult;
 use crate::settings;
 use crate::timing;
 
@@ -110,7 +107,7 @@ pub struct VCode<I: VCodeInst> {
     prologue_epilogue_ranges: Option<(InsnIndex, InsnIndex, Box<[(InsnIndex, InsnIndex)]>)>,
 
     /// Instruction end offsets
-    insts_layout: RefCell<Vec<u32>>,
+    insts_layout: RefCell<(Vec<u32>, u32)>,
 }
 
 /// A builder for a VCode function body. This builder is designed for the
@@ -303,7 +300,7 @@ impl<I: VCodeInst> VCode<I> {
             safepoint_insns: vec![],
             safepoint_slots: vec![],
             prologue_epilogue_ranges: None,
-            insts_layout: RefCell::new(vec![]),
+            insts_layout: RefCell::new((vec![], 0)),
         }
     }
 
@@ -535,20 +532,22 @@ impl<I: VCodeInst> VCode<I> {
             }
         }
 
-        self.insts_layout
-            .borrow_mut()
-            .extend(insts_layout.into_iter());
+        *self.insts_layout.borrow_mut() = (insts_layout, buffer.cur_offset());
 
         buffer
     }
 
     /// Generates unwind info.
     #[cfg(feature = "unwind")]
-    pub fn unwind_info(&self) -> CodegenResult<Option<unwind::UnwindInfo>> {
+    pub fn unwind_info(
+        &self,
+    ) -> crate::result::CodegenResult<Option<crate::isa::unwind::UnwindInfo>> {
+        let layout = &self.insts_layout.borrow();
         I::UnwindInfo::create_unwind_info(
             self.abi.unwind_info_kind(),
             &self.insts,
-            &self.insts_layout.borrow(),
+            &layout.0,
+            layout.1,
             self.prologue_epilogue_ranges.as_ref().unwrap(),
         )
     }