rustc_codegen_ssa: append blocks to functions w/o creating a builder.

compiler/rustc_codegen_llvm/src/builder.rs

@@ -118,24 +118,16 @@ macro_rules! builder_methods_for_value_instructions {
 }
 
 impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
-    fn new_block<'b>(cx: &'a CodegenCx<'ll, 'tcx>, llfn: &'ll Value, name: &'b str) -> Self {
-        let mut bx = Builder::with_cx(cx);
-        let llbb = unsafe {
-            let name = SmallCStr::new(name);
-            llvm::LLVMAppendBasicBlockInContext(cx.llcx, llfn, name.as_ptr())
-        };
-        bx.position_at_end(llbb);
+    fn build(cx: &'a CodegenCx<'ll, 'tcx>, llbb: &'ll BasicBlock) -> Self {
+        let bx = Builder::with_cx(cx);
+        unsafe {
+            llvm::LLVMPositionBuilderAtEnd(bx.llbuilder, llbb);
+        }
         bx
     }
 
-    fn with_cx(cx: &'a CodegenCx<'ll, 'tcx>) -> Self {
-        // Create a fresh builder from the crate context.
-        let llbuilder = unsafe { llvm::LLVMCreateBuilderInContext(cx.llcx) };
-        Builder { llbuilder, cx }
-    }
-
-    fn build_sibling_block(&self, name: &str) -> Self {
-        Builder::new_block(self.cx, self.llfn(), name)
+    fn cx(&self) -> &CodegenCx<'ll, 'tcx> {
+        self.cx
     }
 
     fn llbb(&self) -> &'ll BasicBlock {
@@ -144,12 +136,22 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
 
     fn set_span(&mut self, _span: Span) {}
 
-    fn position_at_end(&mut self, llbb: &'ll BasicBlock) {
+    fn append_block(cx: &'a CodegenCx<'ll, 'tcx>, llfn: &'ll Value, name: &str) -> &'ll BasicBlock {
         unsafe {
-            llvm::LLVMPositionBuilderAtEnd(self.llbuilder, llbb);
+            let name = SmallCStr::new(name);
+            llvm::LLVMAppendBasicBlockInContext(cx.llcx, llfn, name.as_ptr())
         }
     }
 
+    fn append_sibling_block(&mut self, name: &str) -> &'ll BasicBlock {
+        Self::append_block(self.cx, self.llfn(), name)
+    }
+
+    fn build_sibling_block(&mut self, name: &str) -> Self {
+        let llbb = self.append_sibling_block(name);
+        Self::build(self.cx, llbb)
+    }
+
     fn ret_void(&mut self) {
         unsafe {
             llvm::LLVMBuildRetVoid(self.llbuilder);
@@ -1144,10 +1146,6 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
         unsafe { llvm::LLVMBuildZExt(self.llbuilder, val, dest_ty, UNNAMED) }
     }
 
-    fn cx(&self) -> &CodegenCx<'ll, 'tcx> {
-        self.cx
-    }
-
     fn do_not_inline(&mut self, llret: &'ll Value) {
         llvm::Attribute::NoInline.apply_callsite(llvm::AttributePlace::Function, llret);
     }
@@ -1161,6 +1159,12 @@ impl StaticBuilderMethods for Builder<'a, 'll, 'tcx> {
 }
 
 impl Builder<'a, 'll, 'tcx> {
+    fn with_cx(cx: &'a CodegenCx<'ll, 'tcx>) -> Self {
+        // Create a fresh builder from the crate context.
+        let llbuilder = unsafe { llvm::LLVMCreateBuilderInContext(cx.llcx) };
+        Builder { llbuilder, cx }
+    }
+
     pub fn llfn(&self) -> &'ll Value {
         unsafe { llvm::LLVMGetBasicBlockParent(self.llbb()) }
     }

compiler/rustc_codegen_llvm/src/coverageinfo/mod.rs

@@ -223,7 +223,8 @@ fn declare_unused_fn(cx: &CodegenCx<'ll, 'tcx>, def_id: &DefId) -> Instance<'tcx
 
 fn codegen_unused_fn_and_counter(cx: &CodegenCx<'ll, 'tcx>, instance: Instance<'tcx>) {
     let llfn = cx.get_fn(instance);
-    let mut bx = Builder::new_block(cx, llfn, "unused_function");
+    let llbb = Builder::append_block(cx, llfn, "unused_function");
+    let mut bx = Builder::build(cx, llbb);
     let fn_name = bx.get_pgo_func_name_var(instance);
     let hash = bx.const_u64(0);
     let num_counters = bx.const_u32(1);

compiler/rustc_codegen_llvm/src/intrinsic.rs

@@ -678,7 +678,8 @@ fn gen_fn<'ll, 'tcx>(
     cx.apply_target_cpu_attr(llfn);
     // FIXME(eddyb) find a nicer way to do this.
     unsafe { llvm::LLVMRustSetLinkage(llfn, llvm::Linkage::InternalLinkage) };
-    let bx = Builder::new_block(cx, llfn, "entry-block");
+    let llbb = Builder::append_block(cx, llfn, "entry-block");
+    let bx = Builder::build(cx, llbb);
     codegen(bx);
     llfn
 }