[WIP] Add a Trap sink to code generation (#279)

* First draft of TrapSink implementation.

* Add trap sink calls to 'trapif' and 'trapff' recipes.

* Add SourceLoc to trap sink calls, and add trap sink calls to all loads and stores.

* Add IntegerDivisionByZero trap to div recipe.

* Only emit load/store traps if 'notrap' flag is not set on the instruction.

* Update filetest machinery to add new trap sink functionality.

* Update filetests to include traps in output.

* Add a few more trap outputs to filetests.

* Add trap output to CLI tool.

lib/filetests/src/test_binemit.rs

@@ -102,6 +102,10 @@ impl binemit::CodeSink for TextSink {
     fn reloc_jt(&mut self, reloc: binemit::Reloc, jt: ir::JumpTable) {
         write!(self.text, "{}({}) ", reloc, jt).unwrap();
     }
+
+    fn trap(&mut self, code: ir::TrapCode, _srcloc: ir::SourceLoc) {
+        write!(self.text, "{} ", code).unwrap();
+    }
 }
 
 impl SubTest for TestBinEmit {

lib/filetests/src/test_compile.rs

@@ -111,4 +111,5 @@ impl binemit::CodeSink for SizeSink {
     ) {
     }
     fn reloc_jt(&mut self, _reloc: binemit::Reloc, _jt: ir::JumpTable) {}
+    fn trap(&mut self, _code: ir::TrapCode, _srcloc: ir::SourceLoc) {}
 }