rustc_codegen_ssa: use more consistent naming.

Ensure:
- builders always have a `bx` suffix;
- backend basic blocks always have an `llbb` suffix,
- paired builders and basic blocks have consistent prefixes.

Author: nnethercote

compiler/rustc_codegen_ssa/src/mir/block.rs

@@ -95,10 +95,10 @@ impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> {
 
             debug!("llblock: creating cleanup trampoline for {:?}", target);
             let name = &format!("{:?}_cleanup_trampoline_{:?}", self.bb, target);
-            let trampoline = Bx::append_block(fx.cx, fx.llfn, name);
-            let mut trampoline_bx = Bx::build(fx.cx, trampoline);
+            let trampoline_llbb = Bx::append_block(fx.cx, fx.llfn, name);
+            let mut trampoline_bx = Bx::build(fx.cx, trampoline_llbb);
             trampoline_bx.cleanup_ret(self.funclet(fx).unwrap(), Some(lltarget));
-            trampoline
+            trampoline_llbb
         } else {
             lltarget
         }
@@ -1459,20 +1459,20 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 //          bar();
                 //      }
                 Some(&mir::TerminatorKind::Abort) => {
-                    let cs_bb =
+                    let cs_llbb =
                         Bx::append_block(self.cx, self.llfn, &format!("cs_funclet{:?}", bb));
-                    let cp_bb =
+                    let cp_llbb =
                         Bx::append_block(self.cx, self.llfn, &format!("cp_funclet{:?}", bb));
-                    ret_llbb = cs_bb;
+                    ret_llbb = cs_llbb;
 
-                    let mut cs_bx = Bx::build(self.cx, cs_bb);
-                    let cs = cs_bx.catch_switch(None, None, &[cp_bb]);
+                    let mut cs_bx = Bx::build(self.cx, cs_llbb);
+                    let cs = cs_bx.catch_switch(None, None, &[cp_llbb]);
 
                     // The "null" here is actually a RTTI type descriptor for the
                     // C++ personality function, but `catch (...)` has no type so
                     // it's null. The 64 here is actually a bitfield which
                     // represents that this is a catch-all block.
-                    let mut cp_bx = Bx::build(self.cx, cp_bb);
+                    let mut cp_bx = Bx::build(self.cx, cp_llbb);
                     let null = cp_bx.const_null(
                         cp_bx.type_i8p_ext(cp_bx.cx().data_layout().instruction_address_space),
                     );
@@ -1481,30 +1481,31 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     cp_bx.br(llbb);
                 }
                 _ => {
-                    let cleanup_bb =
+                    let cleanup_llbb =
                         Bx::append_block(self.cx, self.llfn, &format!("funclet_{:?}", bb));
-                    ret_llbb = cleanup_bb;
-                    let mut cleanup_bx = Bx::build(self.cx, cleanup_bb);
+                    ret_llbb = cleanup_llbb;
+                    let mut cleanup_bx = Bx::build(self.cx, cleanup_llbb);
                     funclet = cleanup_bx.cleanup_pad(None, &[]);
                     cleanup_bx.br(llbb);
                 }
             }
             self.funclets[bb] = Some(funclet);
             ret_llbb
         } else {
-            let bb = Bx::append_block(self.cx, self.llfn, "cleanup");
-            let mut bx = Bx::build(self.cx, bb);
+            let cleanup_llbb = Bx::append_block(self.cx, self.llfn, "cleanup");
+            let mut cleanup_bx = Bx::build(self.cx, cleanup_llbb);
 
             let llpersonality = self.cx.eh_personality();
             let llretty = self.landing_pad_type();
-            let lp = bx.cleanup_landing_pad(llretty, llpersonality);
+            let lp = cleanup_bx.cleanup_landing_pad(llretty, llpersonality);
 
-            let slot = self.get_personality_slot(&mut bx);
-            slot.storage_live(&mut bx);
-            Pair(bx.extract_value(lp, 0), bx.extract_value(lp, 1)).store(&mut bx, slot);
+            let slot = self.get_personality_slot(&mut cleanup_bx);
+            slot.storage_live(&mut cleanup_bx);
+            Pair(cleanup_bx.extract_value(lp, 0), cleanup_bx.extract_value(lp, 1))
+                .store(&mut cleanup_bx, slot);
 
-            bx.br(llbb);
-            bx.llbb()
+            cleanup_bx.br(llbb);
+            cleanup_llbb
         }
     }
 

compiler/rustc_codegen_ssa/src/mir/mod.rs

@@ -148,10 +148,10 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
     let debug_context = cx.create_function_debug_context(instance, &fn_abi, llfn, &mir);
 
     let start_llbb = Bx::append_block(cx, llfn, "start");
-    let mut bx = Bx::build(cx, start_llbb);
+    let mut start_bx = Bx::build(cx, start_llbb);
 
     if mir.basic_blocks.iter().any(|bb| bb.is_cleanup) {
-        bx.set_personality_fn(cx.eh_personality());
+        start_bx.set_personality_fn(cx.eh_personality());
     }
 
     let cleanup_kinds = analyze::cleanup_kinds(&mir);
@@ -180,7 +180,7 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
         caller_location: None,
     };
 
-    fx.per_local_var_debug_info = fx.compute_per_local_var_debug_info(&mut bx);
+    fx.per_local_var_debug_info = fx.compute_per_local_var_debug_info(&mut start_bx);
 
     // Evaluate all required consts; codegen later assumes that CTFE will never fail.
     let mut all_consts_ok = true;
@@ -206,29 +206,29 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
 
     // Allocate variable and temp allocas
     fx.locals = {
-        let args = arg_local_refs(&mut bx, &mut fx, &memory_locals);
+        let args = arg_local_refs(&mut start_bx, &mut fx, &memory_locals);
 
         let mut allocate_local = |local| {
             let decl = &mir.local_decls[local];
-            let layout = bx.layout_of(fx.monomorphize(decl.ty));
+            let layout = start_bx.layout_of(fx.monomorphize(decl.ty));
             assert!(!layout.ty.has_erasable_regions());
 
             if local == mir::RETURN_PLACE && fx.fn_abi.ret.is_indirect() {
                 debug!("alloc: {:?} (return place) -> place", local);
-                let llretptr = bx.get_param(0);
+                let llretptr = start_bx.get_param(0);
                 return LocalRef::Place(PlaceRef::new_sized(llretptr, layout));
             }
 
             if memory_locals.contains(local) {
                 debug!("alloc: {:?} -> place", local);
                 if layout.is_unsized() {
-                    LocalRef::UnsizedPlace(PlaceRef::alloca_unsized_indirect(&mut bx, layout))
+                    LocalRef::UnsizedPlace(PlaceRef::alloca_unsized_indirect(&mut start_bx, layout))
                 } else {
-                    LocalRef::Place(PlaceRef::alloca(&mut bx, layout))
+                    LocalRef::Place(PlaceRef::alloca(&mut start_bx, layout))
                 }
             } else {
                 debug!("alloc: {:?} -> operand", local);
-                LocalRef::new_operand(&mut bx, layout)
+                LocalRef::new_operand(&mut start_bx, layout)
             }
         };
 
@@ -240,7 +240,7 @@ pub fn codegen_mir<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
     };
 
     // Apply debuginfo to the newly allocated locals.
-    fx.debug_introduce_locals(&mut bx);
+    fx.debug_introduce_locals(&mut start_bx);
 
     // Codegen the body of each block using reverse postorder
     for (bb, _) in traversal::reverse_postorder(&mir) {