[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/cretonne/src/binemit/memorysink.rs

@@ -14,7 +14,7 @@
 //! relocations to a `RelocSink` trait object. Relocations are less frequent than the
 //! `CodeSink::put*` methods, so the performance impact of the virtual callbacks is less severe.
 
-use ir::{ExternalName, JumpTable};
+use ir::{ExternalName, JumpTable, TrapCode, SourceLoc};
 use super::{CodeSink, CodeOffset, Reloc, Addend};
 use std::ptr::write_unaligned;
 
@@ -33,15 +33,21 @@ pub struct MemoryCodeSink<'a> {
     data: *mut u8,
     offset: isize,
     relocs: &'a mut RelocSink,
+    traps: &'a mut TrapSink,
 }
 
 impl<'a> MemoryCodeSink<'a> {
     /// Create a new memory code sink that writes a function to the memory pointed to by `data`.
-    pub fn new(data: *mut u8, relocs: &mut RelocSink) -> MemoryCodeSink {
+    pub fn new<'sink>(
+        data: *mut u8,
+        relocs: &'sink mut RelocSink,
+        traps: &'sink mut TrapSink,
+    ) -> MemoryCodeSink<'sink> {
         MemoryCodeSink {
             data,
             offset: 0,
             relocs,
+            traps,
         }
     }
 }
@@ -58,6 +64,12 @@ pub trait RelocSink {
     fn reloc_jt(&mut self, CodeOffset, Reloc, JumpTable);
 }
 
+/// A trait for receiving trap codes and offsets.
+pub trait TrapSink {
+    /// Add trap information for a specific offset.
+    fn trap(&mut self, CodeOffset, SourceLoc, TrapCode);
+}
+
 impl<'a> CodeSink for MemoryCodeSink<'a> {
     fn offset(&self) -> CodeOffset {
         self.offset as CodeOffset
@@ -105,4 +117,9 @@ impl<'a> CodeSink for MemoryCodeSink<'a> {
         let ofs = self.offset();
         self.relocs.reloc_jt(ofs, rel, jt);
     }
+
+    fn trap(&mut self, code: TrapCode, srcloc: SourceLoc) {
+        let ofs = self.offset();
+        self.traps.trap(ofs, srcloc, code);
+    }
 }

lib/cretonne/src/binemit/mod.rs

@@ -8,9 +8,9 @@ mod memorysink;
 
 pub use regalloc::RegDiversions;
 pub use self::relaxation::relax_branches;
-pub use self::memorysink::{MemoryCodeSink, RelocSink};
+pub use self::memorysink::{MemoryCodeSink, RelocSink, TrapSink};
 
-use ir::{ExternalName, JumpTable, Function, Inst};
+use ir::{ExternalName, JumpTable, Function, Inst, TrapCode, SourceLoc};
 use std::fmt;
 
 /// Offset in bytes from the beginning of the function.
@@ -86,6 +86,9 @@ pub trait CodeSink {
 
     /// Add a relocation referencing a jump table.
     fn reloc_jt(&mut self, Reloc, JumpTable);
+
+    /// Add trap information for the current offset.
+    fn trap(&mut self, TrapCode, SourceLoc);
 }
 
 /// Report a bad encoding error.