Add ability to relocate constants using RelocSink

cranelift/filetests/src/test_binemit.rs

@@ -90,6 +90,10 @@ impl binemit::CodeSink for TextSink {
         write!(self.text, ") ").unwrap();
     }
 
+    fn reloc_constant(&mut self, reloc: binemit::Reloc, constant: ir::ConstantOffset) {
+        write!(self.text, "{}({}) ", reloc, constant).unwrap();
+    }
+
     fn reloc_jt(&mut self, reloc: binemit::Reloc, jt: ir::JumpTable) {
         write!(self.text, "{}({}) ", reloc, jt).unwrap();
     }
@@ -313,7 +317,13 @@ impl SubTest for TestBinEmit {
         }
 
         sink.begin_rodata();
-        // TODO: Read-only (constant pool) data.
+
+        // output constants
+        for (_, constant_data) in func.dfg.constants.iter() {
+            for byte in constant_data.iter() {
+                sink.put1(*byte)
+            }
+        }
 
         sink.end_codegen();
 

cranelift/filetests/src/test_compile.rs

@@ -106,6 +106,7 @@ impl binemit::CodeSink for SizeSink {
         _addend: binemit::Addend,
     ) {
     }
+    fn reloc_constant(&mut self, _: binemit::Reloc, _: ir::ConstantOffset) {}
     fn reloc_jt(&mut self, _reloc: binemit::Reloc, _jt: ir::JumpTable) {}
     fn trap(&mut self, _code: ir::TrapCode, _srcloc: ir::SourceLoc) {}
     fn begin_jumptables(&mut self) {}