Remove current_block field of CodegenCx

This field often had the wrong value when using multiple builders at the
same time.

Author: bjorn3

src/builder.rs

@@ -379,9 +379,7 @@ impl<'gcc, 'tcx> BackendTypes for Builder<'_, 'gcc, 'tcx> {
 
 impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
     fn build(cx: &'a CodegenCx<'gcc, 'tcx>, block: Block<'gcc>) -> Self {
-        let bx = Builder::with_cx(cx, block);
-        *cx.current_block.borrow_mut() = Some(block);
-        bx
+        Builder::with_cx(cx, block)
     }
 
     fn llbb(&self) -> Block<'gcc> {
@@ -399,7 +397,6 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
     }
 
     fn switch_to_block(&mut self, block: Self::BasicBlock) {
-        *self.cx.current_block.borrow_mut() = Some(block);
         self.block = block;
     }
 

src/context.rs

@@ -31,8 +31,7 @@ pub struct CodegenCx<'gcc, 'tcx> {
     pub codegen_unit: &'tcx CodegenUnit<'tcx>,
     pub context: &'gcc Context<'gcc>,
 
-    // TODO(antoyo): First set it to a dummy block to avoid using Option?
-    pub current_block: RefCell<Option<Block<'gcc>>>,
+    // TODO(bjorn3): First set it to a dummy function to avoid using Option?
     pub current_func: RefCell<Option<Function<'gcc>>>,
     pub normal_function_addresses: RefCell<FxHashSet<RValue<'gcc>>>,
 
@@ -177,7 +176,6 @@ impl<'gcc, 'tcx> CodegenCx<'gcc, 'tcx> {
             check_overflow,
             codegen_unit,
             context,
-            current_block: RefCell::new(None),
             current_func: RefCell::new(None),
             normal_function_addresses: Default::default(),
             functions: RefCell::new(functions),