Refactor FunctionCx::codgen_terminator

- Move closures defined in codegen_terminator into a separate helper
   structure and implementation.
 - Create helper functions for each of the complex match arms on the
   terminators kind in codegen_terminator.

src/librustc_codegen_ssa/mir/block.rs

@@ -13,6 +13,8 @@ use crate::meth;
 
 use crate::traits::*;
 
+use std::borrow::Cow;
+
 use syntax::symbol::Symbol;
 use syntax_pos::Pos;
 
@@ -21,128 +23,117 @@ use super::place::PlaceRef;
 use super::operand::{OperandValue, OperandRef};
 use super::operand::OperandValue::{Pair, Ref, Immediate};
 
-impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
+/// Used by `FunctionCx::codegen_terminator` for emitting common patterns
-    pub fn codegen_block(
+/// e.g., creating a basic block, calling a function, etc.
-        &mut self,
+struct TerminatorCodegenHelper<'a, 'tcx> {
-        bb: mir::BasicBlock,
+    bb: &'a mir::BasicBlock,
-    ) {
+    terminator: &'a mir::Terminator<'tcx>,
-        let mut bx = self.build_block(bb);
+    funclet_bb: Option<mir::BasicBlock>,
-        let data = &self.mir[bb];
-
-        debug!("codegen_block({:?}={:?})", bb, data);
-
-        for statement in &data.statements {
-            bx = self.codegen_statement(bx, statement);
 }
 
-        self.codegen_terminator(bx, bb, data.terminator());
+impl<'a, 'tcx> TerminatorCodegenHelper<'a, 'tcx> {
-    }
+    /// Returns the associated funclet from `FunctionCx::funclets` for the
-
+    /// `funclet_bb` member if it is not `None`.
-    fn codegen_terminator(
+    fn funclet<'c, 'b, Bx: BuilderMethods<'b, 'tcx>>(
-        &mut self,
+        &self,
-        mut bx: Bx,
+        fx: &'c mut FunctionCx<'b, 'tcx, Bx>,
-        bb: mir::BasicBlock,
+    ) -> Option<&'c Bx::Funclet> {
-        terminator: &mir::Terminator<'tcx>
+        match self.funclet_bb {
-    ) {
+            Some(funcl) => fx.funclets[funcl].as_ref(),
-        debug!("codegen_terminator: {:?}", terminator);
-
-        // Create the cleanup bundle, if needed.
-        let tcx = self.cx.tcx();
-        let span = terminator.source_info.span;
-        let funclet_bb = self.cleanup_kinds[bb].funclet_bb(bb);
-
-        // HACK(eddyb) force the right lifetimes, NLL can't figure them out.
-        fn funclet_closure_factory<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>>(
-            funclet_bb: Option<mir::BasicBlock>
-        ) -> impl for<'b> Fn(
-            &'b FunctionCx<'a, 'tcx, Bx>,
-        ) -> Option<&'b Bx::Funclet> {
-            move |this| {
-                match funclet_bb {
-                    Some(funclet_bb) => this.funclets[funclet_bb].as_ref(),
             None => None,
         }
     }
-        }
-        let funclet = funclet_closure_factory(funclet_bb);
 
-        let lltarget = |this: &mut Self, target: mir::BasicBlock| {
+    fn lltarget<'b, 'c, Bx: BuilderMethods<'b, 'tcx>>(
-            let lltarget = this.blocks[target];
+        &self,
-            let target_funclet = this.cleanup_kinds[target].funclet_bb(target);
+        fx: &'c mut FunctionCx<'b, 'tcx, Bx>,
-            match (funclet_bb, target_funclet) {
+        target: mir::BasicBlock,
+    ) -> (Bx::BasicBlock, bool) {
+        let span = self.terminator.source_info.span;
+        let lltarget = fx.blocks[target];
+        let target_funclet = fx.cleanup_kinds[target].funclet_bb(target);
+        match (self.funclet_bb, target_funclet) {
             (None, None) => (lltarget, false),
-                (Some(f), Some(t_f))
+            (Some(f), Some(t_f)) if f == t_f || !base::wants_msvc_seh(fx.cx.tcx().sess) =>
-                    if f == t_f || !base::wants_msvc_seh(tcx.sess)
+                (lltarget, false),
-                    => (lltarget, false),
-                (None, Some(_)) => {
             // jump *into* cleanup - need a landing pad if GNU
-                    (this.landing_pad_to(target), false)
+            (None, Some(_)) => (fx.landing_pad_to(target), false),
-                }
+            (Some(_), None) => span_bug!(span, "{:?} - jump out of cleanup?", self.terminator),
-                (Some(_), None) => span_bug!(span, "{:?} - jump out of cleanup?", terminator),
+            (Some(_), Some(_)) => (fx.landing_pad_to(target), true),
-                (Some(_), Some(_)) => {
-                    (this.landing_pad_to(target), true)
         }
     }
-        };
 
-        let llblock = |this: &mut Self, target: mir::BasicBlock| {
+    /// Create a basic block.
-            let (lltarget, is_cleanupret) = lltarget(this, target);
+    fn llblock<'c, 'b, Bx: BuilderMethods<'b, 'tcx>>(
+        &self,
+        fx: &'c mut FunctionCx<'b, 'tcx, Bx>,
+        target: mir::BasicBlock,
+    ) -> Bx::BasicBlock {
+        let (lltarget, is_cleanupret) = self.lltarget(fx, target);
         if is_cleanupret {
             // MSVC cross-funclet jump - need a trampoline
 
             debug!("llblock: creating cleanup trampoline for {:?}", target);
-                let name = &format!("{:?}_cleanup_trampoline_{:?}", bb, target);
+            let name = &format!("{:?}_cleanup_trampoline_{:?}", self.bb, target);
-                let mut trampoline = this.new_block(name);
+            let mut trampoline = fx.new_block(name);
-                trampoline.cleanup_ret(funclet(this).unwrap(), Some(lltarget));
+            trampoline.cleanup_ret(self.funclet(fx).unwrap(),
+                                   Some(lltarget));
             trampoline.llbb()
         } else {
             lltarget
         }
-        };
+    }
 
-        let funclet_br =
+    fn funclet_br<'c, 'b, Bx: BuilderMethods<'b, 'tcx>>(
-            |this: &mut Self, bx: &mut Bx, target: mir::BasicBlock| {
+        &self,
-                let (lltarget, is_cleanupret) = lltarget(this, target);
+        fx: &'c mut FunctionCx<'b, 'tcx, Bx>,
+        bx: &mut Bx,
+        target: mir::BasicBlock,
+    ) {
+        let (lltarget, is_cleanupret) = self.lltarget(fx, target);
         if is_cleanupret {
             // micro-optimization: generate a `ret` rather than a jump
             // to a trampoline.
-                    bx.cleanup_ret(funclet(this).unwrap(), Some(lltarget));
+            bx.cleanup_ret(self.funclet(fx).unwrap(), Some(lltarget));
         } else {
             bx.br(lltarget);
         }
-            };
+    }
 
-        let do_call = |
+    /// Call `fn_ptr` of `fn_ty` with the arguments `llargs`, the optional
-            this: &mut Self,
+    /// return destination `destination` and the cleanup function `cleanup`.
+    fn do_call<'c, 'b, Bx: BuilderMethods<'b, 'tcx>>(
+        &self,
+        fx: &'c mut FunctionCx<'b, 'tcx, Bx>,
         bx: &mut Bx,
         fn_ty: FnType<'tcx, Ty<'tcx>>,
         fn_ptr: Bx::Value,
         llargs: &[Bx::Value],
         destination: Option<(ReturnDest<'tcx, Bx::Value>, mir::BasicBlock)>,
-            cleanup: Option<mir::BasicBlock>
+        cleanup: Option<mir::BasicBlock>,
-        | {
+    ) {
         if let Some(cleanup) = cleanup {
             let ret_bx = if let Some((_, target)) = destination {
-                    this.blocks[target]
+                fx.blocks[target]
             } else {
-                    this.unreachable_block()
+                fx.unreachable_block()
             };
             let invokeret = bx.invoke(fn_ptr,
                                       &llargs,
                                       ret_bx,
-                                          llblock(this, cleanup),
+                                      self.llblock(fx, cleanup),
-                                          funclet(this));
+                                      self.funclet(fx));
             bx.apply_attrs_callsite(&fn_ty, invokeret);
 
             if let Some((ret_dest, target)) = destination {
-                    let mut ret_bx = this.build_block(target);
+                let mut ret_bx = fx.build_block(target);
-                    this.set_debug_loc(&mut ret_bx, terminator.source_info);
+                fx.set_debug_loc(&mut ret_bx, self.terminator.source_info);
-                    this.store_return(&mut ret_bx, ret_dest, &fn_ty.ret, invokeret);
+                fx.store_return(&mut ret_bx, ret_dest, &fn_ty.ret, invokeret);
             }
         } else {
-                let llret = bx.call(fn_ptr, &llargs, funclet(this));
+            let llret = bx.call(fn_ptr, &llargs, self.funclet(fx));
             bx.apply_attrs_callsite(&fn_ty, llret);
-                if this.mir[bb].is_cleanup {
+            if fx.mir[*self.bb].is_cleanup {
                 // Cleanup is always the cold path. Don't inline
                 // drop glue. Also, when there is a deeply-nested
                 // struct, there are "symmetry" issues that cause
@@ -151,18 +142,24 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             }
 
             if let Some((ret_dest, target)) = destination {
-                    this.store_return(bx, ret_dest, &fn_ty.ret, llret);
+                fx.store_return(bx, ret_dest, &fn_ty.ret, llret);
-                    funclet_br(this, bx, target);
+                self.funclet_br(fx, bx, target);
             } else {
                 bx.unreachable();
             }
         }
-        };
+    }
+}
 
-        self.set_debug_loc(&mut bx, terminator.source_info);
+/// Codegen implementations for some terminator variants.
-        match terminator.kind {
+impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
-            mir::TerminatorKind::Resume => {
+    /// Generates code for a `Resume` terminator.
-                if let Some(funclet) = funclet(self) {
+    fn codegen_resume_terminator<'b>(
+        &mut self,
+        helper: TerminatorCodegenHelper<'b, 'tcx>,
+        mut bx: Bx,
+    ) {
+        if let Some(funclet) = helper.funclet(self) {
             bx.cleanup_ret(funclet, None);
         } else {
             let slot = self.get_personality_slot(&mut bx);
@@ -178,27 +175,27 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 lp = bx.insert_value(lp, lp1, 1);
                 bx.resume(lp);
             } else {
-                        bx.call(bx.eh_unwind_resume(), &[lp0], funclet(self));
+                bx.call(bx.eh_unwind_resume(), &[lp0],
+                        helper.funclet(self));
                 bx.unreachable();
             }
         }
     }
 
-            mir::TerminatorKind::Abort => {
+    fn codegen_switchint_terminator<'b>(
-                bx.abort();
+        &mut self,
-                bx.unreachable();
+        helper: TerminatorCodegenHelper<'b, 'tcx>,
-            }
+        mut bx: Bx,
-
+        discr: &mir::Operand<'tcx>,
-            mir::TerminatorKind::Goto { target } => {
+        switch_ty: Ty<'tcx>,
-                funclet_br(self, &mut bx, target);
+        values: &Cow<'tcx, [u128]>,
-            }
+        targets: &Vec<mir::BasicBlock>,
-
+    ) {
-            mir::TerminatorKind::SwitchInt { ref discr, switch_ty, ref values, ref targets } => {
+        let discr = self.codegen_operand(&mut bx, &discr);
-                let discr = self.codegen_operand(&mut bx, discr);
         if targets.len() == 2 {
             // If there are two targets, emit br instead of switch
-                    let lltrue = llblock(self, targets[0]);
+            let lltrue = helper.llblock(self, targets[0]);
-                    let llfalse = llblock(self, targets[1]);
+            let llfalse = helper.llblock(self, targets[1]);
             if switch_ty == bx.tcx().types.bool {
                 // Don't generate trivial icmps when switching on bool
                 if let [0] = values[..] {
@@ -218,20 +215,23 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         } else {
             let (otherwise, targets) = targets.split_last().unwrap();
             let switch = bx.switch(discr.immediate(),
-                                           llblock(self, *otherwise),
+                                   helper.llblock(self, *otherwise),
                                    values.len());
             let switch_llty = bx.immediate_backend_type(
                 bx.layout_of(switch_ty)
             );
             for (&value, target) in values.iter().zip(targets) {
                 let llval = bx.const_uint_big(switch_llty, value);
-                        let llbb = llblock(self, *target);
+                let llbb = helper.llblock(self, *target);
                 bx.add_case(switch, llval, llbb)
             }
         }
     }
 
-            mir::TerminatorKind::Return => {
+    fn codegen_return_terminator<'b>(
+        &mut self,
+        mut bx: Bx,
+    ) {
         if self.fn_ty.variadic {
             if let Some(va_list) = self.va_list_ref {
                 bx.va_end(va_list.llval);
@@ -244,7 +244,7 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             }
 
             PassMode::Ignore(IgnoreMode::CVarArgs) => {
-                        bug!("C variadic arguments should never be the return type");
+                bug!("C-variadic arguments should never be the return type");
             }
 
             PassMode::Direct(_) | PassMode::Pair(..) => {
@@ -291,18 +291,22 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         bx.ret(llval);
     }
 
-            mir::TerminatorKind::Unreachable => {
-                bx.unreachable();
-            }
 
-            mir::TerminatorKind::Drop { ref location, target, unwind } => {
+    fn codegen_drop_terminator<'b>(
+        &mut self,
+        helper: TerminatorCodegenHelper<'b, 'tcx>,
+        mut bx: Bx,
+        location: &mir::Place<'tcx>,
+        target: mir::BasicBlock,
+        unwind: Option<mir::BasicBlock>,
+    ) {
         let ty = location.ty(self.mir, bx.tcx()).to_ty(bx.tcx());
         let ty = self.monomorphize(&ty);
         let drop_fn = monomorphize::resolve_drop_in_place(bx.tcx(), ty);
 
         if let ty::InstanceDef::DropGlue(_, None) = drop_fn.def {
             // we don't actually need to drop anything.
-                    funclet_br(self, &mut bx, target);
+            helper.funclet_br(self, &mut bx, target);
             return
         }
 
@@ -317,8 +321,8 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         };
         let (drop_fn, fn_ty) = match ty.sty {
             ty::Dynamic(..) => {
-                        let sig = drop_fn.fn_sig(tcx);
+                let sig = drop_fn.fn_sig(self.cx.tcx());
-                        let sig = tcx.normalize_erasing_late_bound_regions(
+                let sig = self.cx.tcx().normalize_erasing_late_bound_regions(
                     ty::ParamEnv::reveal_all(),
                     &sig,
                 );
@@ -332,12 +336,23 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                  bx.fn_type_of_instance(&drop_fn))
             }
         };
-                do_call(self, &mut bx, fn_ty, drop_fn, args,
+        helper.do_call(self, &mut bx, fn_ty, drop_fn, args,
                        Some((ReturnDest::Nothing, target)),
                        unwind);
     }
 
-            mir::TerminatorKind::Assert { ref cond, expected, ref msg, target, cleanup } => {
+    fn codegen_assert_terminator<'b>(
+        &mut self,
+        helper: TerminatorCodegenHelper<'b, 'tcx>,
+        mut bx: Bx,
+        terminator: &mir::Terminator<'tcx>,
+        cond: &mir::Operand<'tcx>,
+        expected: bool,
+        msg: &mir::AssertMessage<'tcx>,
+        target: mir::BasicBlock,
+        cleanup: Option<mir::BasicBlock>,
+    ) {
+        let span = terminator.source_info.span;
         let cond = self.codegen_operand(&mut bx, cond).immediate();
         let mut const_cond = bx.const_to_opt_u128(cond, false).map(|c| c == 1);
 
@@ -356,7 +371,7 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
 
         // Don't codegen the panic block if success if known.
         if const_cond == Some(expected) {
-                    funclet_br(self, &mut bx, target);
+            helper.funclet_br(self, &mut bx, target);
             return;
         }
 
@@ -364,7 +379,7 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         let cond = bx.expect(cond, expected);
 
         // Create the failure block and the conditional branch to it.
-                let lltarget = llblock(self, target);
+        let lltarget = helper.llblock(self, target);
         let panic_block = self.new_block("panic");
         if expected {
             bx.cond_br(cond, lltarget, panic_block.llbb());
@@ -382,9 +397,9 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         let filename = bx.const_str_slice(filename);
         let line = bx.const_u32(loc.line as u32);
         let col = bx.const_u32(loc.col.to_usize() as u32 + 1);
-                let align = tcx.data_layout.aggregate_align.abi
+        let align = self.cx.tcx().data_layout.aggregate_align.abi
-                    .max(tcx.data_layout.i32_align.abi)
+            .max(self.cx.tcx().data_layout.i32_align.abi)
-                    .max(tcx.data_layout.pointer_align.abi);
+            .max(self.cx.tcx().data_layout.pointer_align.abi);
 
         // Put together the arguments to the panic entry point.
         let (lang_item, args) = match *msg {
@@ -426,20 +441,20 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         let llfn = bx.get_fn(instance);
 
         // Codegen the actual panic invoke/call.
-                do_call(self, &mut bx, fn_ty, llfn, &args, None, cleanup);
+        helper.do_call(self, &mut bx, fn_ty, llfn, &args, None, cleanup);
     }
 
-            mir::TerminatorKind::DropAndReplace { .. } => {
+    fn codegen_call_terminator<'b>(
-                bug!("undesugared DropAndReplace in codegen: {:?}", terminator);
+        &mut self,
-            }
+        helper: TerminatorCodegenHelper<'b, 'tcx>,
-
+        mut bx: Bx,
-            mir::TerminatorKind::Call {
+        terminator: &mir::Terminator<'tcx>,
-                ref func,
+        func: &mir::Operand<'tcx>,
-                ref args,
+        args: &Vec<mir::Operand<'tcx>>,
-                ref destination,
+        destination: &Option<(mir::Place<'tcx>, mir::BasicBlock)>,
-                cleanup,
+        cleanup: Option<mir::BasicBlock>,
-                from_hir_call: _
+    ) {
-            } => {
+        let span = terminator.source_info.span;
         // Create the callee. This is a fn ptr or zero-sized and hence a kind of scalar.
         let callee = self.codegen_operand(&mut bx, func);
 
@@ -454,7 +469,7 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             ty::FnPtr(_) => {
                 (None, Some(callee.immediate()))
             }
-                    _ => bug!("{} is not callable", callee.layout.ty)
+            _ => bug!("{} is not callable", callee.layout.ty),
         };
         let def = instance.map(|i| i.def);
         let sig = callee.layout.ty.fn_sig(bx.tcx());
@@ -466,8 +481,8 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
 
         // Handle intrinsics old codegen wants Expr's for, ourselves.
         let intrinsic = match def {
-                    Some(ty::InstanceDef::Intrinsic(def_id))
+            Some(ty::InstanceDef::Intrinsic(def_id)) =>
-                        => Some(bx.tcx().item_name(def_id).as_str()),
+                Some(bx.tcx().item_name(def_id).as_str()),
             _ => None
         };
         let intrinsic = intrinsic.as_ref().map(|s| &s[..]);
@@ -476,7 +491,7 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             if let Some(destination_ref) = destination.as_ref() {
                 let &(ref dest, target) = destination_ref;
                 self.codegen_transmute(&mut bx, &args[0], dest);
-                        funclet_br(self, &mut bx, target);
+                helper.funclet_br(self, &mut bx, target);
             } else {
                 // If we are trying to transmute to an uninhabited type,
                 // it is likely there is no allotted destination. In fact,
@@ -504,15 +519,15 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 bx.new_vtable(sig, &extra_args)
             }
             Some(ty::InstanceDef::DropGlue(_, None)) => {
-                        // empty drop glue - a nop.
+                // Empty drop glue; a no-op.
                 let &(_, target) = destination.as_ref().unwrap();
-                        funclet_br(self, &mut bx, target);
+                helper.funclet_br(self, &mut bx, target);
                 return;
             }
             _ => bx.new_fn_type(sig, &extra_args)
         };
 
-                // emit a panic or a NOP for `panic_if_uninhabited`
+        // Emit a panic or a no-op for `panic_if_uninhabited`.
         if intrinsic == Some("panic_if_uninhabited") {
             let ty = instance.unwrap().substs.type_at(0);
             let layout = bx.layout_of(ty);
@@ -522,9 +537,9 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 let filename = bx.const_str_slice(filename);
                 let line = bx.const_u32(loc.line as u32);
                 let col = bx.const_u32(loc.col.to_usize() as u32 + 1);
-                        let align = tcx.data_layout.aggregate_align.abi
+                let align = self.cx.tcx().data_layout.aggregate_align.abi
-                            .max(tcx.data_layout.i32_align.abi)
+                    .max(self.cx.tcx().data_layout.i32_align.abi)
-                            .max(tcx.data_layout.pointer_align.abi);
+                    .max(self.cx.tcx().data_layout.pointer_align.abi);
 
                 let str = format!(
                     "Attempted to instantiate uninhabited type {}",
@@ -550,7 +565,7 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 let llfn = bx.get_fn(instance);
 
                 // Codegen the actual panic invoke/call.
-                        do_call(
+                helper.do_call(
                     self,
                     &mut bx,
                     fn_ty,
@@ -561,7 +576,7 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 );
             } else {
                 // a NOP
-                        funclet_br(self, &mut bx, destination.as_ref().unwrap().1);
+                helper.funclet_br(self, &mut bx, destination.as_ref().unwrap().1)
             }
             return;
         }
@@ -582,13 +597,12 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         if intrinsic.is_some() && intrinsic != Some("drop_in_place") {
             let dest = match ret_dest {
                 _ if fn_ty.ret.is_indirect() => llargs[0],
-                        ReturnDest::Nothing => {
+                ReturnDest::Nothing =>
-                            bx.const_undef(bx.type_ptr_to(bx.memory_ty(&fn_ty.ret)))
+                    bx.const_undef(bx.type_ptr_to(bx.memory_ty(&fn_ty.ret))),
-                        }
+                ReturnDest::IndirectOperand(dst, _) | ReturnDest::Store(dst) =>
-                        ReturnDest::IndirectOperand(dst, _) |
+                    dst.llval,
-                        ReturnDest::Store(dst) => dst.llval,
                 ReturnDest::DirectOperand(_) =>
-                            bug!("Cannot use direct operand with an intrinsic call")
+                    bug!("Cannot use direct operand with an intrinsic call"),
             };
 
             let args: Vec<_> = args.iter().enumerate().map(|(i, arg)| {
@@ -620,7 +634,7 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                                 layout: bx.layout_of(ty),
                             };
 
-                                },
+                        }
                         mir::Operand::Copy(_) |
                         mir::Operand::Move(_) => {
                             span_bug!(span, "shuffle indices must be constant");
@@ -654,7 +668,7 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             }
 
             if let Some((_, target)) = *destination {
-                        funclet_br(self, &mut bx, target);
+                helper.funclet_br(self, &mut bx, target);
             } else {
                 bx.unreachable();
             }
@@ -682,14 +696,14 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             // populate it with a dummy operand so that the users real arguments
             // are not overwritten.
             let i = if sig.variadic && last_arg_idx.map(|x| x == i).unwrap_or(false) {
-                        let layout = match tcx.lang_items().va_list() {
+                let layout = match self.cx.tcx().lang_items().va_list() {
                     Some(did) => bx.cx().layout_of(bx.tcx().type_of(did)),
-                            None => bug!("va_list language item required for C variadics"),
+                    None => bug!("`va_list` language item required for C-variadics"),
                 };
                 let op = OperandRef {
                     val: OperandValue::Immediate(
-                                bx.cx().const_undef(bx.cx().immediate_backend_type(layout))
+                        bx.cx().const_undef(bx.cx().immediate_backend_type(layout)
-                            ),
+                    )),
                     layout: layout,
                 };
                 self.codegen_argument(&mut bx, op, &mut llargs, &fn_ty.args[i]);
@@ -738,7 +752,7 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                             llargs.push(data_ptr);
                             continue 'make_args
                         }
-                                other => bug!("expected a Pair, got {:?}", other)
+                        other => bug!("expected a Pair, got {:?}", other),
                     }
                 } else if let Ref(data_ptr, Some(meta), _) = op.val {
                     // by-value dynamic dispatch
@@ -776,10 +790,96 @@ impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             _ => span_bug!(span, "no llfn for call"),
         };
 
-                do_call(self, &mut bx, fn_ty, fn_ptr, &llargs,
+        helper.do_call(self, &mut bx, fn_ty, fn_ptr, &llargs,
                        destination.as_ref().map(|&(_, target)| (ret_dest, target)),
                        cleanup);
     }
+}
+
+impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
+    pub fn codegen_block(
+        &mut self,
+        bb: mir::BasicBlock,
+    ) {
+        let mut bx = self.build_block(bb);
+        let data = &self.mir[bb];
+
+        debug!("codegen_block({:?}={:?})", bb, data);
+
+        for statement in &data.statements {
+            bx = self.codegen_statement(bx, statement);
+        }
+
+        self.codegen_terminator(bx, bb, data.terminator());
+    }
+
+    fn codegen_terminator(
+        &mut self,
+        mut bx: Bx,
+        bb: mir::BasicBlock,
+        terminator: &mir::Terminator<'tcx>
+    ) {
+        debug!("codegen_terminator: {:?}", terminator);
+
+        // Create the cleanup bundle, if needed.
+        let funclet_bb = self.cleanup_kinds[bb].funclet_bb(bb);
+        let helper = TerminatorCodegenHelper {
+            bb: &bb, terminator, funclet_bb
+        };
+
+        self.set_debug_loc(&mut bx, terminator.source_info);
+        match terminator.kind {
+            mir::TerminatorKind::Resume => {
+                self.codegen_resume_terminator(helper, bx)
+            }
+
+            mir::TerminatorKind::Abort => {
+                bx.abort();
+                bx.unreachable();
+            }
+
+            mir::TerminatorKind::Goto { target } => {
+                helper.funclet_br(self, &mut bx, target);
+            }
+
+            mir::TerminatorKind::SwitchInt {
+                ref discr, switch_ty, ref values, ref targets
+            } => {
+                self.codegen_switchint_terminator(helper, bx, discr, switch_ty,
+                                                  values, targets);
+            }
+
+            mir::TerminatorKind::Return => {
+                self.codegen_return_terminator(bx);
+            }
+
+            mir::TerminatorKind::Unreachable => {
+                bx.unreachable();
+            }
+
+            mir::TerminatorKind::Drop { ref location, target, unwind } => {
+                self.codegen_drop_terminator(helper, bx, location, target, unwind);
+            }
+
+            mir::TerminatorKind::Assert { ref cond, expected, ref msg, target, cleanup } => {
+                self.codegen_assert_terminator(helper, bx, terminator, cond,
+                                               expected, msg, target, cleanup);
+            }
+
+            mir::TerminatorKind::DropAndReplace { .. } => {
+                bug!("undesugared DropAndReplace in codegen: {:?}", terminator);
+            }
+
+            mir::TerminatorKind::Call {
+                ref func,
+                ref args,
+                ref destination,
+                cleanup,
+                from_hir_call: _
+            } => {
+                self.codegen_call_terminator(helper, bx, terminator, func,
+                                             args, destination, cleanup);
+            }
             mir::TerminatorKind::GeneratorDrop |
             mir::TerminatorKind::Yield { .. } => bug!("generator ops in codegen"),
             mir::TerminatorKind::FalseEdges { .. } |