Don't force veneers on island emission

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

@@ -3579,7 +3579,7 @@ impl MachInstEmit for Inst {
                         dest: BranchTarget::Label(jump_around_label),
                     };
                     jmp.emit(&[], sink, emit_info, state);
-                    sink.emit_island(&mut state.ctrl_plane);
+                    sink.emit_island(needed_space + 4, &mut state.ctrl_plane);
                     sink.bind_label(jump_around_label, &mut state.ctrl_plane);
                 }
             }
@@ -3776,7 +3776,7 @@ fn emit_return_call_common_sequence(
             dest: BranchTarget::Label(jump_around_label),
         };
         jmp.emit(&[], sink, emit_info, state);
-        sink.emit_island(&mut state.ctrl_plane);
+        sink.emit_island(space_needed + 4, &mut state.ctrl_plane);
         sink.bind_label(jump_around_label, &mut state.ctrl_plane);
     }
 

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

@@ -2984,6 +2984,10 @@ impl MachInstLabelUse for LabelUse {
         }
     }
 
+    fn worst_case_veneer_size() -> CodeOffset {
+        20
+    }
+
     /// Generate a veneer into the buffer, given that this veneer is at `veneer_offset`, and return
     /// an offset and label-use for the veneer's use of the original label.
     fn generate_veneer(

cranelift/codegen/src/isa/riscv64/inst/emit.rs

@@ -1189,7 +1189,7 @@ impl MachInstEmit for Inst {
                 // we need to emit a jump table here to support that jump.
                 let distance = (targets.len() * 2 * Inst::INSTRUCTION_SIZE as usize) as u32;
                 if sink.island_needed(distance) {
-                    sink.emit_island(&mut state.ctrl_plane);
+                    sink.emit_island(distance, &mut state.ctrl_plane);
                 }
 
                 // Emit the jumps back to back
@@ -3104,7 +3104,7 @@ fn emit_return_call_common_sequence(
             dest: BranchTarget::Label(jump_around_label),
         }
         .emit(&[], sink, emit_info, state);
-        sink.emit_island(&mut state.ctrl_plane);
+        sink.emit_island(space_needed + 4, &mut state.ctrl_plane);
         sink.bind_label(jump_around_label, &mut state.ctrl_plane);
     }
 

cranelift/codegen/src/isa/riscv64/inst/mod.rs

@@ -2014,6 +2014,10 @@ impl MachInstLabelUse for LabelUse {
         }
     }
 
+    fn worst_case_veneer_size() -> CodeOffset {
+        8
+    }
+
     /// Generate a veneer into the buffer, given that this veneer is at `veneer_offset`, and return
     /// an offset and label-use for the veneer's use of the original label.
     fn generate_veneer(

cranelift/codegen/src/isa/s390x/inst/mod.rs

@@ -3406,6 +3406,10 @@ impl MachInstLabelUse for LabelUse {
         0
     }
 
+    fn worst_case_veneer_size() -> CodeOffset {
+        0
+    }
+
     /// Generate a veneer into the buffer, given that this veneer is at `veneer_offset`, and return
     /// an offset and label-use for the veneer's use of the original label.
     fn generate_veneer(

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

@@ -2742,6 +2742,10 @@ impl MachInstLabelUse for LabelUse {
         }
     }
 
+    fn worst_case_veneer_size() -> CodeOffset {
+        0
+    }
+
     fn generate_veneer(self, _: &mut [u8], _: CodeOffset) -> (CodeOffset, LabelUse) {
         match self {
             LabelUse::JmpRel32 | LabelUse::PCRel32 => {