Implement unwind support for ARM64 Windows

bytecodealliance · Sep 19, 2024 · 43926a3 · 43926a3
1 parent d0cdac7
commit 43926a3
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Showing 7 changed files with 472 additions and 53 deletions.
diff --git a/cranelift/codegen/src/isa/aarch64/abi.rs b/cranelift/codegen/src/isa/aarch64/abi.rs
@@ -725,6 +725,13 @@ impl ABIMachineSpec for AArch64MachineDeps {
         if incoming_args_diff > 0 {
             // Decrement SP to account for the additional space required by a tail call.
             insts.extend(Self::gen_sp_reg_adjust(-(incoming_args_diff as i32)));
+            if flags.unwind_info() {
+                insts.push(Inst::Unwind {
+                    inst: UnwindInst::StackAlloc {
+                        size: incoming_args_diff,
+                    },
+                });
+            }
 
             // Move fp and lr down.
             if setup_frame {
@@ -921,6 +928,11 @@ impl ABIMachineSpec for AArch64MachineDeps {
         let stack_size = frame_layout.fixed_frame_storage_size + frame_layout.outgoing_args_size;
         if stack_size > 0 {
             insts.extend(Self::gen_sp_reg_adjust(-(stack_size as i32)));
+            if flags.unwind_info() {
+                insts.push(Inst::Unwind {
+                    inst: UnwindInst::StackAlloc { size: stack_size },
+                });
+            }
         }
 
         insts

diff --git a/cranelift/codegen/src/isa/aarch64/mod.rs b/cranelift/codegen/src/isa/aarch64/mod.rs
@@ -138,10 +138,11 @@ impl TargetIsa for AArch64Backend {
                     )?,
                 ))
             }
-            UnwindInfoKind::Windows => {
-                // TODO: support Windows unwind info on AArch64
-                None
-            }
+            UnwindInfoKind::Windows => Some(UnwindInfo::WindowsArm64(
+                crate::isa::unwind::winarm64::create_unwind_info_from_insts(
+                    &result.buffer.unwind_info[..],
+                )?,
+            )),
             _ => None,
         })
     }

diff --git a/cranelift/codegen/src/isa/unwind.rs b/cranelift/codegen/src/isa/unwind.rs
@@ -11,6 +11,9 @@ pub mod systemv;
 #[cfg(feature = "unwind")]
 pub mod winx64;
 
+#[cfg(feature = "unwind")]
+pub mod winarm64;
+
 /// CFA-based unwind information used on SystemV.
 pub type CfaUnwindInfo = systemv::UnwindInfo;
 
@@ -39,6 +42,9 @@ pub enum UnwindInfo {
     /// System V ABI unwind information.
     #[cfg(feature = "unwind")]
     SystemV(CfaUnwindInfo),
+    /// Windows Arm64 ABI unwind information.
+    #[cfg(feature = "unwind")]
+    WindowsArm64(winarm64::UnwindInfo),
 }
 
 /// Unwind pseudoinstruction used in VCode backends: represents that
@@ -197,3 +203,39 @@ pub enum UnwindInst {
         return_addresses: bool,
     },
 }
+
+struct Writer<'a> {
+    buf: &'a mut [u8],
+    offset: usize,
+}
+
+impl<'a> Writer<'a> {
+    pub fn new(buf: &'a mut [u8]) -> Self {
+        Self { buf, offset: 0 }
+    }
+
+    fn write_u8(&mut self, v: u8) {
+        self.buf[self.offset] = v;
+        self.offset += 1;
+    }
+
+    fn write_u16_le(&mut self, v: u16) {
+        self.buf[self.offset..(self.offset + 2)].copy_from_slice(&v.to_le_bytes());
+        self.offset += 2;
+    }
+
+    fn write_u16_be(&mut self, v: u16) {
+        self.buf[self.offset..(self.offset + 2)].copy_from_slice(&v.to_be_bytes());
+        self.offset += 2;
+    }
+
+    fn write_u32_le(&mut self, v: u32) {
+        self.buf[self.offset..(self.offset + 4)].copy_from_slice(&v.to_le_bytes());
+        self.offset += 4;
+    }
+
+    fn write_u32_be(&mut self, v: u32) {
+        self.buf[self.offset..(self.offset + 4)].copy_from_slice(&v.to_be_bytes());
+        self.offset += 4;
+    }
+}